U.S. Depar tmentof Transpor tation

Federal AviationAdministration

Charles A. DeJohnStephen J.H. VéronneauAlex M. WolbrinkJulie G. LarcherFederal Aviation AdministrationCivil Aeromedical InstituteOklahoma City, Oklahoma 73125

David W. SmithUniversity of OklahomaNorman, Oklahoma 73019

Joan GarrettMedAire, Inc.Phoenix, Arizona 85006

May 2000

Final Report

This document is available to the publicthrough the National Technical InformationService, Springfield, Virginia 22161.

Office of Aviation MedicineWashington, D.C. 20591

The Evaluation of In-FlightMedical Care Aboard SelectedU.S. Air Carriers: 1996 to 1997

DOT/FAA/AM-00/13

N O T I C E

This document is disseminated under the sponsorship ofthe U.S. Department of Transportation in the interest of

information exchange. The United States Governmentassumes no liability for the contents thereof.

iii

Technical Report Documentation Page

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

DOT/FAA/AM-00/134. Title and Subtitle 5. Report Date

The Evaluation of In-Flight Medical Care Aboard Selected U.S. AirCarriers: 1996 to 1997

May 2000

6. Performing Organization Code

7. Author(s) 8. Performing Organization Report No.

DeJohn, C.A., Véronneau, S.J.H., Wolbrink, A.M., Larcher, J.G.1;Smith, D.W.2; and Garrett, J.3

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)

11. Contract or Grant No.

1FAA Civil Aeromedical Institute , P.O. Box 25082, Oklahoma City, OK 731252University of Oklahoma, Norman, OK 730193MedAire, Inc., Phoenix, AZ 85006

DTFA 02-97P53665

12. Sponsoring Agency name and Address 13. Type of Report and PeriodCovered

Office of Aviation MedicineFederal Aviation Administration 14. Sponsoring Agency Code

800 Independence Ave., S.W.Washington, DC 2059115. Supplemental Notes

This work was performed under task AMB-97-TOX-20316. Abstract

Medical care in-flight and the FAA-mandated medical kit have been studied for many years. This studyincludes a detailed correlation between in-flight medical care, patient response in-flight, and post-flightfollow-up, in an effort to evaluate in-flight medical care delivery on US airlines and re-evaluate the FAA-mandated in-flight medical kit. A survey of five US domestic air carriers from October 1, 1996, toSeptember 30, 1997, showed 1132 in-flight medical incidents. These airlines accounted forapproximately 22% of scheduled US domestic enplanements during the period. There was good overallagreement between in-flight and post-flight diagnoses (70% of cases), and passenger conditionimproved in a majority of cases (60%), suggesting that in-flight diagnoses were generally accurate andtreatment was appropriate. Results indicated that bronchodilator inhalers, oral antihistamines, and non-narcotic analgesics, all of which were obtained from other passengers, were used frequently enough tosupport a suggestion to include them in the medical kit.

17. Key Words 18. Distribution Statement

In-Flight Medical Emergencies, In-Flight Fatalities, In-Flight Medical Care, Medical Flight Diversions, In-Flight Medical Kit

Document is available to the public throughthe National Technical Information Service,Springfield, Virginia 22161

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price

Unclassified Unclassified 26Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

v

TABLE OF CONTENTS

INTRODUCTION-------------------------------------------------------------------------------------------------1

METHODS ----------------------------------------------------------------------------------------------------------1

Sources of Data ------------------------------------------------------------------------------------------------1

Nature of the Data --------------------------------------------------------------------------------------------2

Potential Additions to In-flight Medical Kit -------------------------------------------------------------2

Evaluation of In-flight Medical Care ----------------------------------------------------------------------3

RESULTS -------------------------------------------------------------------------------------------------------------3

Categories of In-flight Medical Events --------------------------------------------------------------------3

Diversions of Flights With In-flight Medical Events ---------------------------------------------------3

Frequency of In-flight Medical Kit Use -------------------------------------------------------------------4

Overall Patient Response In-flight -------------------------------------------------------------------------4

Patient Response Associated With In-flight Medical Kit Use ----------------------------------------5

Medical Personnel Onboard During In-flight Medical Events ---------------------------------------5

Medical Kit Users During In-flight Medical Events ----------------------------------------------------5

Diversions and Medical Kit Users During In-flight Medical Events --------------------------------6

Patient Disposition Following In-flight Medical Events-----------------------------------------------6

Fatalities Associated With In-flight Medical Events ----------------------------------------------------7

Potential Additions to the In-flight Medical Kit --------------------------------------------------------7

Comparison of In-flight and Hospital Discharge Diagnostic Categories ------------------------ 11

DISCUSSION ----------------------------------------------------------------------------------------------------- 12

Limitations of the Study ----------------------------------------------------------------------------------- 12

Frequency of In-flight Medical Events ------------------------------------------------------------------ 13

Categories of In-flight Medical Events ------------------------------------------------------------------ 13

Diversions of Flights With In-flight Medical Events ------------------------------------------------- 13

Diversion Categories for In-flight Medical Events---------------------------------------------------- 14

Diversions and Medical Kit Use -------------------------------------------------------------------------- 14

Overall Patient Response In-flight ----------------------------------------------------------------------- 14

Patient Response Associated With In-flight Medical Kit Use -------------------------------------- 14

Medical Personnel Onboard and Medical Kit User --------------------------------------------------- 14

Diversions and Medical Kit User ------------------------------------------------------------------------- 15

Patient Disposition Following In-flight Medical Events--------------------------------------------- 15

Fatalities Associated With In-flight Medical Events -------------------------------------------------- 15

Potential Additions to the Medical Kit ----------------------------------------------------------------- 16

Comparison of In-flight and Hospital Discharge Diagnostic Categories ------------------------ 16

Severity of In-flight Medical Incidents ------------------------------------------------------------------ 16

CONCLUSIONS ------------------------------------------------------------------------------------------------- 16

RECOMMENDATIONS --------------------------------------------------------------------------------------- 17

REFERENCES----------------------------------------------------------------------------------------------------- 17

APPENDIX A

Table A-1. Frequency of Use of Medical Kit Items -------------------------------------------------A1

Table A-2. Frequency of Use of Items Not Included in the Medical Kit -----------------------A1

List A-1. Information Provided by MedAire -------------------------------------------------------A2

List A-2. Data Coded by CAMI ----------------------------------------------------------------------A2

List A-3. CAMI Diagnostic Code Categories ------------------------------------------------------A2

List A-4. Treatment Code Categories ----------------------------------------------------------------A3

List A-5. Discharge Diagnostic Code Categories --------------------------------------------------A3

List A-6. Outcome Code Categories -----------------------------------------------------------------A3

vi

1

THE EVALUATION OF IN-FLIGHT MEDICAL CARE ABOARD

SELECTED U.S. AIR CARRIERS: 1996 TO 1997

INTRODUCTION

On March 3, 1981, the Public Citizen HealthResearch Group of the Aviation Consumer ActionProject (ACAP) petitioned to amend the FederalAviation Regulations (FARs) to require the carriageof emergency medical equipment on commercialflights in addition to the FAA required first aid kit.The petition urged that US air carriers be required tohave onboard emergency equipment and medicationthat would enable crew-members and/or medicallyqualified passengers to respond to any in-flight emer-gency. On March 14, 1985, the Federal AviationAdministration (FAA) published Notice of ProposedRulemaking (NPRM) Number 85-9 on emergencymedical equipment and on January 6, 1986, pub-lished a final rule requiring medical kits on commer-cial aircraft, although airlines have never beenspecifically mandated to provide medical attention topassengers (Federal Aviation Administration, 1986).

The FAA-mandated medical kit has been the topicof study for many years (Hordinsky & George, 1991a;Hordinsky & George, 1991b; Thibeault, 1998;DeJohn, Véronneau, and Hordinsky, 1997). A pri-mary question of interest is whether additional itemsshould be included by regulation in the FAA requiredmedical kit. The current medical kit, as mandatedunder Title 14 of the Code of Federal Regulations(CFR) Part 67, §67.121.309(d) and shown in TableA-1, has a limited number of items. Additional drugs,or drugs with different routes of administration,might be useful in specific incidents. Attitudes to-ward the medical kit have varied widely and severalrecent studies have asserted that the FAA mandatedin-flight medical kit is inadequate. Speizer, Rennie &Breton (1989) found that none of the 260 passengersarriving at the Los Angeles International airportduring a one year period from 1985 to 1986, whodeveloped medical complaints in-flight, benefitedfrom the equipment or drugs available, no deathswere prevented, and the absence of qualified person-nel onboard may have rendered any in-flight medicalkit useless. In contrast, Cottrell et al. (1989) reportedthat 26% of 157 health care providers who used thekit in-flight thought that it was very useful, 55% felt

that it was somewhat useful, and 18% felt that it wasnot of any benefit, and Cummins and Schubach(1989) suggested that though the medical kit con-tained useful items, it was inadequate to deal withseveral problems that may occur in-flight and sug-gested several medications be added to the kit toimprove it. In addition, Rosenberg and Pak (1997)listed what they broadly classified as mechanical andlogistical limitations that made kits inadequate fordealing with emergencies. In their review, they madethe observation that in-flight medical problems oftenrequire the administration of medications not foundin the kit, which frequently may be obtained fromother passengers. Also, Prew (1997) went as far as tostate that some medical experts believe that withoutspecial care, including drugs and a defibrillator, thereis not much chance of long-term survival for an in-flight cardiac patient. These studies and significanttechnical shifts in the last few years suggest that thecontents of the medical kit might be re-evaluated andchanges considered.

While there have been several studies that haveevaluated in-flight medical care aboard commercialairlines (Rodenberg, 1987; Cummins et al., 1988;Speizer, Rennie, & Breton, 1989; Cummins &Schubach, 1989; Cottrell et al., 1989; Hordinsky &George, 1991a; Hordinsky & George, 1991b;Rosenberg & Pak, 1997; DeJohn, Véronneau, &Hordinsky, 1997), they generally did not include adetailed correlation between medical care and patientresponse in-flight, and post-flight follow-up. Thepresent study attempts to compare patient responseto in-flight medical treatment with follow-up infor-mation in an effort to evaluate in-flight medicaltreatment on domestic US air carriers, and the appro-priateness of flight diversions for medical reasons.

METHODS

Sources of Data. A survey was undertaken of in-flight medical care aboard domestic US air carriersthat contract with MedAire, Inc. for in-flight medi-cal support. MedAire is a private medical service

2

company that provides in-flight assistance to airlinesduring medical incidents. Normally this assistancetakes the form of a radio patch between the aircraftand a ground-based emergency-room physician whoadvises the in-flight medical provider on medicaltreatment decisions, and the aircrew on diversiondecisions. Only those incidents that involved an air-to-ground radio patch with MedAire were includedin the survey. The survey included five US airlinesthat contracted with MedAire, and showed therewere 1132 in-flight medical incidents from October1, 1996 to September 30, 1997. These air carriersaccounted for approximately 22% of the total num-ber of enplanements for US domestic scheduled aircarriers during this period (Austin, 1997).

Nature of the Data. Internal data collection formswere used by MedAire to collect the data at the timeof each in-flight event. After the event, a record wascompleted by the MedAire staff, based on their ownexperience and the advice of any medical personnelonboard at the time of the incident. The MedAirestaff then entered the information from each recordinto a Microsoft Access® database designed by theFAA Civil Aeromedical Institute (CAMI).

Information provided by MedAire included pa-tient demographics, flight information, flight diver-sion status, details of the in-flight medical event,outcome, and post-flight discharge diagnosis (List A-1). Most of the information supplied by MedAire wasclosed-formatted, allowing a specific list of responses;however, some information was open-ended, permit-ting a wide variation of the entered data. Six areas ofprimary interest included: patient presentation, in-flight diagnosis, treatment, medical kit items used,outcome, and post-flight discharge diagnosis. Allopen-ended items were later coded by the CAMImedical staff into fixed categories more suitable todata analysis including patient demographics, flightinformation, diversion status, in-flight treatmentcategory, CAMI diagnostic category, outcome cat-egory, and post-flight discharge diagnostic category(List A-5). Patient demographics included age, gen-der, and medical history. Flight information in-cluded the origin, destination, and type of aircraft.Treatment data, provided in text format, were codedinto several categories, including specific medica-tions, patient monitoring, and supportive therapy(List A-4). Similarly, outcome data were coded toreflect what type of post-flight medical treatmentfacility the patient was transferred to, or whether

follow-up treatment was refused or canceled (List A-6). Also, discharge diagnostic category was codedusing the post-flight discharge diagnosis data (List A-5). In addition, the patient’s demographics, present-ing symptoms, in-flight diagnosis, in-flight treatment,response to in-flight treatment, medical kit itemsused, diversion status of the flight, outcome, andpost-flight discharge diagnosis when available, wereall considered in coding the CAMI diagnostic cat-egory (List A-3).

Data collection was unique in that it involvedradio communication between an aircraft in-flightwith a physician on the ground. This environmentoften limits the ability of the ground-based physicianto accurately assess and diagnose the airborne emer-gency situation. The patient can be interviewed andobserved with the most rudimentary medical equip-ment, essentially a stethoscope and sphygmomanom-eter. Additionally, only a limited choice of treatmentsare normally available in-flight. Although items usedfrom the medical kit may be supplemented by medi-cations obtained from other passengers, signs andsymptoms are likely to be the only reliable informa-tion available. As a result, onboard medical conclu-sions are frequently tentative, and often an accuratediagnosis will not be possible. Consequently, boththe in-flight diagnosis and treatment must be viewedwith caution and accepted as the best possible con-clusions and actions that could be made during an in-flight medical incident. However, the additionalquality assurance provided by CAMI physician re-view allowed for accurate post-flight categorizationof cases, which reflected detailed post-flight verifica-tion data, including patient outcome, and post-flightdischarge diagnosis.

Potential Additions to In-flight Medical Kit(IMK). Frequency tables of usage rates for specificitems or categories of items were used to determinepotential additions to the medical kit. Items thatwere frequently obtained from other passengers andused, but not available in the currently mandatedmedical kit (Table A-2) were primary candidates foradditions. The criteria for selection of potential addi-tions to the IMK resulted from a review of the data,which suggested that additional items should beconsidered for inclusion in the medical kit if: (1) theitem was used in more than 2% of all cases, or (2) theitem was used in more than 1% of all cases where 1/3 or more of those cases occurred in a single category.For example, diphenhydramine is available in injectable

3

form in the medical kit but may also be commonlyobtained as Benadryl, an oral preparation, from an-other passenger. Oral Benadryl use was thereforecompared to injectable diphenhydramine use to evalu-ate whether the oral form of the drug should beincluded in the medical kit. Although an attempt wasmade to collect data on in-flight medical providerpreferences, there were not enough responses fromin-flight medical care providers to that item on thequestionnaire to properly evaluate the question.

Unfortunately, this approach does not addressitems that are not included in the medical kit and notroutinely carried by passengers, but could have beenuseful if they had been available to the health careprovider in-flight. Such items could not be defined inthis study because of insufficient responses to theappropriate question on the questionnaire.

Evaluation of In-flight Medical Care. Other spe-cific analyses included examining the quality of in-flight medical care delivery; patient response toin-flight medical care, including final outcome; anda comparison between in-flight diagnosis and treat-ment and hospital diagnosis and treatment.

RESULTS

We studied 1132 in-flight medical events whichoccurred on five US domestic Part 121 air carriersfrom October 1, 1996 to September 30, 1997. Of the1125 cases that reported gender, 596 were femalesand 529 were males. The mean age of the 1057individuals for whom age was known was 49 years,and the range was seven weeks to 106 years.

Categories of In-flight Medical Events. Each casewas assigned a category (List A-3) based on thepatient’s presenting symptoms, in-flight diagnosis,in-flight treatment, response to in-flight treatment,medical kit items used, the diversion status of theflight, outcome, post-flight discharge diagnosis, andmedical history (Table 1). Although vasovagal casesoccurred with the greatest frequency, the most com-mon serious categories of in-flight medical eventswere cardiac (20%), neurological (12%), and respira-tory (8%).

Diversions of Flights With In-flight MedicalEvents. A diversion was defined as a flight that landedat an airport other than the scheduled destination dueto an in-flight medical event involving a passenger.Of the 1132 in-flight medical incidents (IMIs), 145

Category Frequency PercentVasovagal 254 22.4Cardiac 221 19.5Neurological 134 11.8Respiratory 92 8.1Gastrointestinal 90 7.7Trauma 60 5.3Endocrine 53 4.7Miscellaneous 52 4.6Psychological 38 3.4Vascular 35 3.1OB/GYN 33 2.9Allergic Reaction 27 2.4ENT 20 1.8Urological 18 1.6Not Reported 3 0.3Unknown 2 0.2Total 1132 100

Table 1. Categories of In-flight Medical Incidents.

(13%) resulted in an emergency diversion. This rep-resents a diversion rate of about one passenger per onemillion enplanements.

Of the 449 cases where physicians were onboard,70 (16%) flights were diverted for medical reasons.In contrast, of the 683 cases where there was nophysician onboard, 75 (11%) flights were diverted. Achi-square test performed on the data, which is sum-marized in Table 2, shows that the presence of aphysician was associated with an increase in thepercentage of diversions (χ2 = 4.75, p < 0.03).

DiversionYes No Total

Yes 70 379 449No 75 608 683

PhysicianOnboard

Total 145 987 1132

Table 2. Flight Diversions and Physician Presence.

4

Table 3 summarizes flight diversions by category.There were no diversions reported for the “ENT,”“Urological,” “Not Reported,” and “Unknown” cat-egories. Cardiac incidents had the greatest percentageof diversions (30%) followed by obstetrical-gyneco-logical incidents (21.2%), and neurological inci-dents (19.4%).

Frequency of In-flight Medical Kit (IMK) Use.The IMK was used in 533 out of 1132 in-flight medicalincidents (47%), it was not used 543 times (48%), and itsuse status was not reported in 56 cases (5%).

Table 4 shows the relationship between the num-ber of times the IMK was used and whether or not theflight was diverted. Unreported cases are not in-cluded in the table; therefore, the total of diversionsand non-diversions is not equal to 1132. The kit wasused in 82 out of 127 cases (65%) when the flightdiverted, and in 451 out of 949 flights (48%) that didnot divert. The data, therefore, indicate that there isa greater likelihood that the IMK was used whenthere was a diversion (χ2 = 12.34, n = 1, p < .001).

Overall Patient Response In-flight. The medicalcondition of passengers improved in 60% of cases,remained the same in 12% of cases, worsened in 2%of cases, and was not reported by MedAire in 26% ofcases as indicated in Table 5.

Category CategoryTotal

CategoryPercent

Diversionsin Category

CategoryDiversion Rate

(%)

Percent ofAll

Diversions(%)

Cardiac 221 19.5 66 30.0 45.5OB/GYN 33 2.9 7 21.2 4.8Neurological 134 11.8 26 19.4 18.0Vascular 35 3.1 5 14.3 3.4Endocrine 53 4.7 6 11.3 4.1Respiratory 92 8.1 9 9.8 6.2Miscellaneous 52 4.6 5 9.6 3.4Gastrointestinal 90 8.0 7 7.8 4.8Psychological 38 3.4 2 5.3 1.4Vasovagal 254 22.4 10 3.9 6.9Allergic Reaction 27 2.4 1 3.7 0.7Trauma 60 5.3 1 1.7 0.7Total* 1089* 96.2* 145* N/A* 100*

*Total does not equal 100% because “Not Reported” and “Unknown” categories are not included.

Table 3. Flight Diversion Frequency by Category.

IMK UsedDiversion Yes No Total

Yes 82 45 127No 451 498 949

Total 533 543 1076

Table 4. Flight Diversions by In-flight MedicalKit Use.

Response Frequency PercentImproved 675 60Unchanged 136 12Worsened 27 2Not Reported 294 26Total 1132 100

Table 5. Overall Patient Response In-flight.

Patient ImprovedYes No Total

Yes 291 57 348No 385 106 491

PhysicianOnboard

Total 676 163 839

Table 6. Patient Improvement Associated WithPhysician Presence.

5

Of the 348 cases (Table 6) where physicians wereonboard and overall patient response was reported,patient condition improved 291 times (84%). Bycomparison, of the 491 cases where there was nophysician onboard and patient response was reported,patient condition improved 385 times, (78%). A chi-square test performed on the data, which is summa-rized in Table 6, showed that the presence or absenceof a physician onboard was unrelated to the numberof patients who improved in-flight.

Patient Response Associated With In-flight Medi-cal Kit Use. Table 7 shows that, in general, use of themedical kit was associated with patient response (χ2

= 8.74, p = 0.013). While there was no significantdifference in the number of patients who improvedin-flight as a result of medical kit use, more patients’conditions worsened with kit use compared to thosewithout kit use (Z = – 0.096, p = 0.011). Thisassociation may have been confounded by differencesin the severity of the cases and, although statisticallysignificant, may not be of clinical importance.

Medical Personnel Onboard During In-flightMedical Events. Data provided by MedAire (List A-1) indicates physicians were available approximately40% of the time, nurses 25% of the time, and EMTs4% of the time as shown in Table 8. “Other” includesphysician’s assistant, nurse practitioner, dentist, andother individuals who may not have been health careprofessionals. “None” implies that the medical kitwas not used.

Medical Kit Users During In-flight MedicalEvents. Table 9 shows how frequently each type ofmedical care provider used the IMK. Cases where themedical kit user was not reported are not shown in thetable. It is interesting to note that physicians did notappear to use the kit proportionately more often thanother groups of health care professionals.

IMK UsedPatient

ResponseYes No Total

Improved 349 314 663Unchanged 73 60 133Worsened 22 5 27Total 444 379 823

Table 7 . Patient Response AssociatedWith In-flight Medical Kit Use.

Medical Personnel Frequency PercentPhysician 449 40Nurse 278 25None 249 22EMT 48 4Other 47 4Not Reported 34 3Paramedic 27 2Total 1132 100

Table 8. Medical Personnel Onboard.

Medical Kit User Onboard Used Kit

Percentof Time

UsedPhysician 449 275 61Nurse 278 190 68Emergency Medical Technician (EMT) 48 28 58Other 41 25 61Paramedic 27 11 41Physician's Assistant 4 2 50Nurse Practitioner 1 1 100Dentist 1 1 100

Table 9. Medical Kit Users.

6

Diversions and Medical Kit Users During In-flight Medical Events. Physicians used the IMKmost often during flights that were diverted (30%),followed by nurses, and EMTs (Table 10). For thisanalysis, two paramedics were re-categorized andincluded in the “Other” category resulting in a totalof eight flight diversions for that category.

Patient Disposition Following In-flight MedicalEvents. Many patients who experienced an in-flightmedical event refused medical advice (RMA), asshown in Table 11. RMA implies that treatment wasindicated but the patient refused further medicaltreatment following the flight. Of those patients whoreceived medical treatment, most were treated at theairport, either in an airport clinic or by EMTs orparamedics. The next largest group of patients wereseen in the emergency room (ER).

Nine out of the 15 fatalities were not transportedto a treatment facility and are tabulated separately inTable 11 as “Un-transported Fatalities.” The remaining

six fatalities were transported to treatment facilitiesbut eventually expired, and they are categorized ac-cording to the type of treatment facility involved.

In those cases where further medical assistance ata ground facility was canceled, it was not possible todetermine if cancellations were made because thesituation changed and the patient no longer requiredmedical attention, or the patient refused furthermedical support. Of the 102 cancellations for furthermedical assistance shown in Table 11, 60% weremade by the MedAire physician, 33% by the aircrew(usually the captain), 3% by the patient, and 4% ofthe time it was not known who canceled the response.

Of the 179 patients transported to the hospital,173 were admitted with an average stay of 2.8 days,although the type of floor or service was known inonly ten cases. Of those ten cases, three were admittedto the medical floor, two to the neurological service,two to the obstetrical/gynecological floor, and one toorthopedics.

IMK User Frequencyof

Diversions

Percentof

DiversionsPhysician 43 30Nurse 28 19EMT 3 2Other 8 6None 45 31Not Reported 18 12Total 145 100

Table 10 . Flight Diversions and Medical Kit Users.

PatientDisposition RMA Airport ER Hospital Canceled

NotReported

Un-transportedFatalities Total

Number ofPatients

340 289 196 179 102 17 9 1132

Percent ofPatients

30 26 17 15 9 2 1 100

Table 11 . Patient Post-flight Disposition.

7

As shown in Table 12, of the 173 patients admit-ted to the hospital, 40 were admitted to an intensive/critical care unit (ICU/CCU) with an average lengthof stay of 3.1 days, while 30 patients were admittedto a telemetry unit for an average of 2.7 days, and 5patients were sent to an intermediate care unit stayingan average of 2.2 days.

Of the 40 patients admitted to an ICU/CCU, 38were admitted to a medical unit with an averagelength of stay of three days; one patient was admittedto a cardiac unit for a day, and another was admittedto a surgical unit for a day. Although only one patientwas sent to a cardiac intensive care unit, this does notimply that there was only one cardiac intensive carecase. Many hospitals do not have separate cardiac orsurgical intensive care units; therefore, all seriouscases go to a general medical CCU or ICU. When thecategories of the 38 patients who were admitted togeneral ICUs/CCUs were checked, it was discoveredthat 27 of the patients were diagnosed as cardiac cases inflight. In addition, the one case admitted to the surgicalintensive care unit was also diagnosed as a cardiacpatient. Consequently, 27 of the 40 patients who wereadmitted to critical care units were cardiac cases.

Five of the 173 patients admitted to the hospitalwere sent to intermediate care units with an averagelength of stay of 2.2 days. Two patients were sent toa general medical intermediate care unit, one patientwas sent to a cardiac unit, another to a surgical unit,and one patient was sent to an intermediate care unitwhere the type of unit was not specified. The averagelength of stay for the two medical patients was 2.5days, while the length of stay for the cardiac, surgical,and unknown patients was four days, one day, andone day respectively. While this implies that only onecardiac patient was sent to an intermediate care unit,many hospitals do not have separate cardiac interme-diate care units and patients are simply sent to a

medical intermediate care unit. When the categoriesof the two patients admitted to general intermediatecare units were checked, it was discovered that one ofthem was a cardiac case while one was a neurologicalcase; consequently, two of the five patients who wereadmitted to intermediate care units were actuallycardiac cases.

Fatalities Associated With In-flight MedicalEvents. A fatality was defined as a passenger deaththat occurred at any time in-flight, during transportto a treatment facility, or at a treatment facility.Fifteen of 1132 cases were fatalities for a case fatalityrate of 13.3 per 1000 patients. A summary of thepost-flight diagnostic categories for fatalities (CAMIdiagnostic categories) is shown in Table 13.

In this, study two fatalities that were initially mis-classified as “Respiratory” cases (as shown in paren-theses) were later determined to be “Cardiac” deathswhen additional information became available fromthe hospital. In other cases, the status of the patientwas unknown at the end of the flight; however,details were subsequently available from the admit-ting hospital or emergency room.

Potential Additions to the In-flight Medical Kit.A review and analysis of the data suggested criteria forinclusion of additional items in the medical kit: (1) ifthe item was used in more than 2% of all cases, or (2)if the item was used in more than 1% of all caseswhere 1/3 or more of those cases occurred in a singlecategory. Table 14 summarizes the items that meteither of these criteria.

Oxygen, supportive care (i.e., orange juice, re-cline, cover with blanket, etc.), close patient moni-toring, and analgesics met the first criterion (> 2% ofall cases) by wide margins. Nitroglycerin, other thanfrom the medical kit, met both criteria (> 2% of allcases and more than 1/3 of cases in a single category).

Specialty CareUnit

Number ofPatients

Average Length ofStay (Days)

ICU/CCU 40 3.1Telemetry 30 2.7Intermediate 5 2.2Total 75 2.7

Table 12 . Distribution of Patients in Specialty Care Units.

8

Age Sex Presentation Category Kit User Diversion Outcome61 F Short of breath and

vomiting.Cardiac

(Respiratory)Nurse No Pronounced dead

at hospital.79 F Passenger expired

according to the nurse onboard. Pulseless, apneic,pupils fixed and dilated.*

Cardiac Nurse No Pronounced deadat gate.

75 M Problems breathing, andunconscious.

Cardiac Physician No Pronounced deadat gate.

27 F Not breathing. CPR wasinitiated. In cardiac arrest.

Cardiac Not Reported Yes Expired athospital.

65 M Pale, not breathing, notmoving, cold to the touch.*

Cardiac Not Reported No Pronounced deadat gate.

67 F Unconscious, unresponsive,unable to find pulse.

Cardiac None Yes Expired athospital.

71 M Short of breath. Cardiac(Respiratory)

None No Admitted tohospital; ICU for 3days & telemetryfor 6 days beforeexpiring.

71 M Difficulty breathing. Cardiac None No Pronounced deadat gate.

68 M Difficulty breathing.Respiratory arrest.

Cardiac Nurse No Pronounced deadat gate.

70 F Respiratory arrest. Cardiac None No Pronounced deadat gate.

80 M Syncopal episode inlavatory; vomited andunconscious.

Cardiac None No Expired atunreported time.

32 F Abdominal pain. OB/GYN Other No Admitted tohospital wherepatient laterexpired.

36 F Unconscious and notbreathing.

Drug Overdose Paramedic Yes Patient expired athospital.

48 M Cardiac arrest.* Cardiac Physician No Patient was laterpronounced dead.

40 M Non-responsive. Cancer None Yes Transported tohospital where helater expired.

* Indicates cases where information suggests patient may have died on the airplane.

Table 13 . Summary of Fatalities

9

A bronchodilator inhaler and an oral antihistaminemet the second criterion (> 1% of all cases and morethan 1/3 of cases in a single category).

After identifying items that might be consideredfor inclusion in the medical kit, the impact of theseitems on patient response to in-flight medical carewas investigated. In Table 15, frequencies are shownabove, while percentages associated with changes inpatient condition are shown below in parentheses.On average, a passenger’s condition improved ap-proximately 84% of the time when these measureswere employed. Interestingly, close patient monitor-ing was associated with improvement about 90% ofthe time. Of those items that could be added to the kit,a bronchodilator inhaler and an oral antihistamine

appeared to have the greatest effect on positive pa-tient response to treatment; however, analgesic therapyalso showed good results.

Table 16 summarizes cases where bronchodilatortherapy was used in-flight, while reflecting whetheroxygen was used, and the passenger’s response to thetreatment.

Item

Percentof TotalCases Category

CategoryFrequency

TotalFrequency

Oxygen 58.2 N/A N/A N/ASupportive care 40.8 N/A N/A N/AMonitor patient 36.1 N/A N/A N/AAnalgesic 4.1 N/A N/A N/ANitroglycerin (not from kit) 3.4 Cardiac 35 38Bronchodilator inhaler 1.6 Respiratory 14 18Oral antihistamine 1.0 Allergic

reaction8 11

Table 14. Summary of Response Frequencies for Potential Additions to the Medical Kit.

Item Worse Unchanged ImprovedMonitor patient 9

(3.0%)21

(7.0%)271

(90.0%)Nitroglycerin(not from kit)

1(3.1%)

3(9.4%)

28(87.5%)

BronchodilatorInhaler

1(6.3%)

1(6.3%)

14(87.5%)

OralAntihistamine

0(0.0%)

1(12.5%)

7(87.5%)

Supportive Care 13(3.6%)

51(14.2%)

296(82.2%)

Oxygen 25(4.6%)

79(14.5%)

442(81.0%)

Analgesic 0(0.0%)

8(29.6%)

19(70.4%)

Mean 2.9 13.4 83.7

Table 15. Effect on Patient Response of Treatments/Potential Additionsto the Medical Kit.

Bronchodilator Therapy CasesOxygen

Used Worsened Unchanged ImprovedYes 1 1 12No - - 2

Table 16. Oxygen Use in Bronchodilator Therapy.

10

In-flight Diagnostic Category

Car

diac

(70)

Tra

uma

(22)

Vas

ovag

al(3

2)

Res

pira

tory

(20)

Mis

c.(1

5)

GI(

15)

Neu

rolo

gica

l(22

)

Vas

cula

r(1

2)

OB

/GY

N(8

)

End

ocrin

e(8

)

EN

T(5

)

Alle

rgic

Rea

ctio

n(4

)

Psy

chol

ogic

al(3

)

Uro

logi

cal(

3)

Cardiac (62) 57 0 4 0 0 0 0 0 0 1 0 0 0 0

Trauma (22) 0 22 0 0 0 0 0 0 0 0 0 0 0 0

Vasovagal (29) 5 0 22 1 0 0 1 0 0 0 0 0 0 0

Respiratory (20) 0 0 1 18 1 0 0 0 0 0 0 0 0 0

Misc. (22) 2 0 1 1 12 3 3 0 0 0 0 0 0 0

GI (14) 1 0 0 0 0 11 1 0 1 0 0 0 0 0

Neurological (10) 0 0 0 0 0 0 9 1 0 0 0 0 0 0

Vascular (23) 3 0 3 0 1 1 5 9 0 1 0 0 0 0

OB/GYN (8) 0 0 0 0 1 0 0 0 7 0 0 0 0 0

Endocrine (10) 0 0 1 0 0 0 2 1 0 6 0 0 0 0

ENT (5) 0 0 0 0 0 0 0 0 0 0 5 0 0 0

Allergic (4)Reaction

0 0 0 0 0 0 0 0 0 0 0 4 0 0

Psychological (6) 2 0 0 0 0 0 1 0 0 0 0 0 3 0

Pos

t-fli

ghtD

iagn

ostic

Cat

egor

y

Urological (4) 0 0 0 0 0 0 0 1 0 0 0 0 0 3

Table 17 . Comparison of In-flight and Post-flight Diagnostic Categories.

11

The overwhelming majority of patients who re-ceived both bronchodilator and oxygen therapy im-proved; however, there were not enough cases thatdid not receive oxygen therapy in conjunction withbronchodilator therapy to allow a proper compara-tive analysis. In fact, the two cases that did not receiveoxygen with a bronchodilator improved.

Comparison of In-flight and Hospital DischargeDiagnostic Categories. Post-flight diagnostic cat-egories were obtained from patients who were seen inthe emergency room, airport clinic, or hospital. Post-flight diagnostic categories were known in 239 out of1132 cases, or approximately 21% of the time. Thosecases where in-flight diagnostic category and post-flight discharge diagnostic category were known arecompared in Table 17. Cases classified as “Unknown”were not included in the comparison. In-flight diag-nostic categories are shown as columns, while post-flight diagnostic categories are shown as rows. Thefigure in parentheses next to each category indicatesthe number of cases in that category. All cases wherein-flight diagnostic category agrees with post-flightdiagnostic category appear on the diagonal in thetable. In-flight and post-flight diagnostic categoriesagreed in 188 out of 239 cases (79%). Acceptingpost-flight diagnoses as accurate, further compari-sons are possible. For example, while 70 patients wereassigned a cardiac diagnostic category in-flight, only62 were similarly classified on discharge from thehospital, with agreement in 57 cases. There are twoways that the in-flight category can disagree with thepost-flight category: (1) a cardiac category could beassigned in-flight and a non-cardiac category can beassigned post-flight (i.e., over-diagnosis in-flight), or(2) a non-cardiac category could be assigned in-flightwhere a cardiac category is assigned post-flight (i.e.,under-diagnosis in-flight). Examination of the car-

diac column (in-flight diagnostic category) in Table17 reveals that 16 patients were assigned a cardiacdiagnosis in-flight, and were later assigned a non-cardiac diagnosis at hospital discharge, implying thatthese patients might have been over-diagnosed ascardiac patients in-flight. Looking at the cardiac row(post-flight diagnostic category) in Table 17 showsthat five patients who were diagnosed as non-cardiacin-flight, were eventually classified as cardiac casespost-flight, suggesting that these patients might havebeen under-diagnosed as cardiac patients in-flight.

A comparison of in-flight and post-flight diag-noses for cardiac cases is shown in Table 18. A Chi-square analysis of these data shows that there wasgeneral agreement between in-flight diagnostic cat-egories and post-flight discharge diagnostic catego-ries (χ2 = 154.6, n = 1, p < .001).

Next, a post-hoc analysis was performed using aMcNemar test on the data to determine if cardiacpatients were over-diagnosed or under-diagnosed in-flight. The results suggests that cardiac patients wereneither under- nor over-identified in-flight.

Similarly it can be demonstrated that non-neuro-logical cases were over-identified as neurological in-flight (χ2 = 8.6, n = 1, p < .003) while vascularincidents were under-diagnosed in-flight and attrib-uted to other causes (χ2 = 5.9, n = 1, p < .01). Of the14 vascular cases, five were diagnosed in-flight asneurological cases, three as cardiac, three as vasova-gal, one as gastrointestinal, one as endocrine, and oneas miscellaneous. Of the 13 non-neurological casesthat were diagnosed as neurological cases in-flight,two were later determined to be endocrine, one waslater diagnosed as gastrointestinal, one as psychologi-cal, five as vascular, one as vasovagal, and three asmiscellaneous.

Post-flight Discharge CategoryIn-flight Category Cardiac Non-cardiac TotalCardiac 57 13 70Non-cardiac 5 157 162Total 62 170 232

Table 18. Comparison of In-flight and Post-Flight Diagnoses for Cardiac Cases.

12

An agreement rate of 92.2% was calculated forcardiac cases by summing the total cases where in-flight and post-flight diagnoses agreed (57 cardiacplus 157 non-cardiac) and dividing by the totalnumber of cases (232). Agreement rates for the othercategories are summarized in Table 19.

DISCUSSION

Limitations of the Study. The experience of air-lines that contract with MedAire for support duringin-flight medical emergencies may not be representa-tive of the entire airline industry. First, many of themore serious incidents may be reported on contract-ing airlines simply because a consistent approach totheir management is available. Second, the manage-ment of in-flight medical incidents may differ fromthe management of incidents on other airlines. Forexample, because knowledgeable emergency medicalstaff are involved, the number of flight diversions formedical reasons may decrease. Although conclusionsabout the value of specific medical equipment orsupplies can be made about incidents managed underthe auspices of MedAire, the application of thoseconclusions to the airline industry in general may notbe appropriate. Essentially, any conclusions aboutthe larger population of medical incidents are some-what speculative.

Category

AgreementRate(%)

Cardiac 92.2Trauma 100.0Vasovagal 92.9Respiratory 98.3Miscellaneous 94.6GI 97.1Neurological 94.1Vascular 92.9OB/GYN 99.2Endocrine 97.5ENT 100.0Allergic Reaction 100.0Psychological 98.7Urological 99.6

Table 19. Comparison of In-flight andHospital Diagnoses for all Categories.

Frequency of In-flight Medical Events. We ana-lyzed 1132 in-flight medical incidents that occurredaboard five US domestic airlines from October 1,1996 to September 30, 1997. These airlines carriedapproximately 1.4 million passengers during thattime; therefore, our in-flight medical incident ratewas about 8 per million enplanements. This rate islow compared with rates found in earlier studies. Forexample, a 1996 Air Transport Association surveyyielded 17 incidents per million enplanements (AirTransport Association, 1998), while a British Air-ways study found 31 incidents per millionenplanements (Harding & Mills, 1993), and a Qantasstudy reported 48 incidents per million enplanements(Davis & Degotardi, 1982). Differences between thisstudy and similar studies are probably due to thedifferent methodologies employed. Only those inci-dents that involved an air-to-ground radio patch areincluded in the MedAire data. Minor in-flight medi-cal incidents, that would have presumably been in-cluded in the other studies, would not have beenincluded in this study because they would not haverequired an air-to-ground patch.

Categories of In-flight Medical Events. The sixmost common causes of in-flight medical events werevasovagal, cardiac, neurological, respiratory, gas-trointestinal, and trauma. Category frequencies insimilar studies vary widely as shown in Table 20.

Differences in data collection methods and classi-fication schemes employed in the various studiesmake meaningful comparison between studies diffi-cult. For example, some studies were limited to asingle airline and included only cases where the in-flight medical kit was opened and a medical recordform, contained in the kit, was completed (Cottrell etal., 1989). Other studies limited data collection topassengers arriving at a single airport (Cummins &Schubach, 1989; Speizer, Rennie & Breton, 1989).In addition, the categorization of in-flight eventsvaried from one study to another. As an example,some studies clearly defined cases as “vasovagal syn-cope” (Harding & Mills, 1993), while others werenot as clear as to what was included in the classifica-tion of “syncope” (Cummins & Schubach, 1989).

Diversions of Flights With In-flight MedicalEvents. Diversions for medical reasons occurred foronly one in one million passengers. The same rate hasbeen found in earlier studies (Cummins & Schubach,1989; Schoken & Lederer, 1970), indicating thatdespite advances in medicine over the years, the

13

introduction of the in-flight medical kit in 1986, andthe more recent incorporation of in-flight tele-medicine, the diversion rate for medical reasons hasremained small but constant.

Although most operations that occur on a “once-in-a-million” basis can generally be considered anacceptable risk, there are two reasons that medicaldiversions are important: (1) they are time consum-ing and expensive events, and (2) many of them canbe avoided. Diversions can affect the schedules oflarge numbers of passengers who require accommo-dation and possible financial compensation for theirinconvenience. As an example, diversions cost BritishAirways up to £500,000 ($893,000 US) in 1996(Kahn, 1996). In addition, a series of time-consum-ing steps must be taken for any diversion to takeplace. Not only must arrangements be made to re-ceive and transport the ill passenger on landing, butthe available medical facilities at a potential alternatedestination must be considered. It would be unwiseto divert to another airport and determine too latethat ground transportation is not available for thepatient, or that the local medical facility cannotprovide the care required for the patient’s condition.Also, the pilot, along with flight dispatch, mustdetermine a suitable landing airport, which may ormay not be serviced by the company or be familiar to the

flight crew. Landing weight is also a consideration, andvaluable fuel may have to be jettisoned to attain asuitable landing weight for a premature touch-down.

Consequently, methods of avoiding flight diver-sions are constantly being sought. Three possibilitiesinclude: (1) the presence of an onboard physician, (2)passenger education, and (3) medical kit improve-ments. However, results showed that physicians wereonboard only 40% of the time and were associatedwith the highest diversion rate among in-flight medi-cal care providers. Educating travelers about thenature of the aircraft cabin environment has beensuggested, since many passengers believe that cabinpressure is the same as sea level and know very littleabout hypoxia, dehydration, or the heightened ef-fects of medication or alcohol at altitude (Kahn,1996). Assertions that the kits were inadequate fordealing with in-flight emergencies (Rosenberg &Pak, 1997), passengers did not benefit from theequipment or drugs available (Speizer, Rennie, &Breton, 1989), and no deaths were prevented (Speizer,Rennie, & Breton, 1989), have led researchers tosuggest several improvements (Thibeault, 1998).

Approximately 28 out of the 145 (19%), of theflight diversions in this study were probably unnec-essary in light of subsequent follow-up information.In three of the 28 cases (two cardiac cases and one

Common Causes of In-flight Medical Incidents(Percent of Total Incidents)

CAMI/MedAire

(N=1132)

Donaldson& Pearn(1996)

(N=454)

Cummins &Schubach

(1989)1

(N=1107)

Davies &Degotardi(1982)2

(N=45)

Speizeret al. (1989)

(N=260)3

CottrellEt al.

(1989)

(N=362)

Harding& Mills(1993)5

(N=2139)Vasovagal 22 35 4 10 6 29 20Cardiac 20 16 20 29 20 16 3Neurological 12 4 8 4 4 4 03

Respiratory 8 6 8 2 9 10 5Gastrointestinal 8 13 15 6 12 04 12Trauma 5 4 14 7 6 04 04

1In-flight cases only.2Physician reported incidents only.3Includes only the 123 cases where emergency department diagnosis was given.4Category was not listed among the six most common in this study.5Data from April 1990 to March 1991 British Airways study.

Table 20. Common Causes of In-flight Medical Incidents.

14

respiratory case) the passengers refused further medi-cal advice; therefore, there was no post-flight follow-up. The remaining 25 cases did not appear to beserious enough to have warranted a flight diversionfor medical reasons, according to post-flight treat-ment facility discharge information. Of the 25 cases,nine were eventually diagnosed as vasovagal syncope,five as dehydration, four as gastroenteritis, two asviral infections, two as non-cardiac chest pain, one asanxiety, one as false labor, and one as sickle cellanemia. However, it must be emphasized that thesedeterminations were arrived at after careful consider-ation of post-flight treatment data that were notavailable during the flight. Earlier studies reported aneven higher percentage of unnecessary diversions. Intheir study, Schoken and Lederer (1970) estimatedthat about half of the unscheduled landings couldhave been avoided, while Cummins and Schubach(1989) stated that all seven of the unscheduled land-ings in their study were probably unnecessary.

Diversion Categories for In-flight Medical Events.It is interesting to note that those categories of in-flight medical events that occurred with the highestfrequency did not necessarily account for the greatestnumber of flight diversions. As an example, whilevasovagal incidents represented the greatest numberof cases, the percentage of diversions for that categorywas low compared with other, more serious, catego-ries. Other studies showed similar results. The threecategories that accounted for the most diversions inthis study were cardiac, neurological, and vasovagal,while a 1970 American Airlines study (Schoken &Lederer) listed the three most common reasons assyncope, heart attack, and dyspnea.

Diversions and Medical Kit Use. In this studythere was a proportionately greater likelihood thatthe IMK was used when there was a flight diversion.Although this association is statistically significant, itis probably confounded by differences in severitybetween categories. This may be because the medicalkit is used more frequently in severe incidents, whichare more likely to result in a diversion; whereas,minor incidents, which are less likely to cause the kitto be used, are also less likely to result in a diversion.

Overall Patient Response In-flight . It is encour-aging to note that in over half of the cases in ourstudy, passenger condition improved, whereas pas-senger condition worsened in only a few cases. Al-though patient condition improved most of the timewhen there was a physician onboard, it was not

significantly different from when a physician was notpresent. It is also possible that the 26% of unreportedcases were of a less serious nature, whereas the moreserious cases were followed-up and reported on. Thiswould imply that more patients might have actuallyimproved than are indicated by the data. These datasuggest that even under the difficult conditions en-countered in-flight, diagnoses and treatment of pas-sengers appears to be appropriate most of the time,whether or not a physician is aboard. These data aremore encouraging than the 32% improvement ratereported by Cottrell et al. (1989).

Patient Response Associated With In-flight Medi-cal Kit Use. Our results showed that medical kit useappeared to have an inverse relationship on patientresponse; that is, kit use was associated with worsen-ing patient condition. While these results appear tobe illogical, they are not, because the data are not theresult of a repeated measures experiment. The pa-tients in the three categories (worsened, unchanged,and improved) were different; therefore, the severityof each case was a confounding variable. It is possiblethat those patients whose condition improved hadless severe medical conditions that improved withoutkit use, while patients whose condition worsenedmay have had more severe medical conditions thatwould have become worse with or without kit use. Itis also interesting to note that, while 60% of patientsimproved overall in-flight, as shown in Table 5, only31% of patients improved when the IMK was used asshown in Table 7. This is probably because themedical kit was used for more serious cases and wasnot required for less severe cases. Stated differently,those cases that involved medical kit use also in-volved the more seriously ill passengers who were lesslikely to improve in-flight.

Medical Personnel Onboard and Medical KitUser. While physicians identified themselves in-flightapproximately 40% of the time, they were the medi-cal provider over half the time when the IMK wasused. In other studies, the availability of physiciansduring in-flight medical events has been shown tovary widely, from about 8% to approximately 85%(Mills & Harding, 1983; Speizer, Rennie & Breton,1989; Cummins et al., 1988; Cottrell et al., 1989;and Hordinsky & George, 1991b). It is not clear,however, whether physicians were actually onboardmore often but simply did not identify themselves.For example, one study reported that at least one halfof physicians surveyed stated they were reluctant to

15

respond, usually because the problem would be out-side their field of practice, or because they believedthey would be greatly hampered in conducting treat-ment on an aircraft (Hays, 1977).

Diversions and Medical Kit User. The resultsimply that when the kit is not used (“None” in Table10), flight diversions occur less frequently. Again,this may be because when the medical kit is not used,the incident may not be as serious, and a diversionwill be less likely.

While EMTs experienced the lowest percentage ofdiversions among identifiable medical provider groupsresponsible for diversions (2%), physicians had thehighest (30%). The higher proportion of diversionsfor physicians might have resulted for a number ofreasons. Physicians would normally be expected totake charge during the most serious in-flight eventsthat would ordinarily require a flight diversion. Also,when they did suggested that a flight should divert,their medical opinion may have weighed more heavilywith the flight crew and the MedAire physician thanwhen less highly trained health care professionalsmade the same suggestion under similar circum-stances. Some of the groups were represented by suchlow frequencies, however, that small changes in thenumber of cases could have produced large changesin the percentage of diversions for that group, pre-venting meaningful analysis.

Patient Disposition Following In-flight MedicalEvents. Out of 1,119 passengers who experienced anin-flight medical event with a known outcome, 345(31%) refused medical advice (RMA). This propor-tion is much greater than a 1989 study by Cumminsand Schubach which found that only 1% of passen-gers with in-flight emergencies declined recommendedadvice.

A cancellation implied that either the medicalsituation changed and treatment was no longer indi-cated, or the patient declined further medical treat-ment. Although it appears that few treatmentcancellations were made by the patient, there is noway of determining how many cancellations mayhave originated with the patient and been relayed bythe aircrew. Cancellations made by the aircrew orpatient imply that a physician may not have beeninvolved in the decision. Fortunately, the MedAirephysician was responsible for the majority of cancel-lations, which is the best situation, as it reflects adecision made by a medical professional in posses-sion of the best available information.

One hundred seventy-three patients were admit-ted to the hospital during the study, with an averagelength of stay of 2.8, days compared with the nationalaverage of 5.2 days for the same period (Centers forDisease Control, 1999). The service to which theywere admitted was known in only 10 of the 173 cases;therefore, meaningful conclusions could not be drawn.

Fatalities Associated With In-flight MedicalEvents. There were 15 fatalities during the one-yearperiod of the study for a case fatality rate of 13.3 per1000 patients. The mean age for fatalities was 59.3years and the range was 32 to 80 years.

Officially, none of the 15 fatalities expired on theaircraft. They were either pronounced dead at thegate or at the hospital. However, information onthree of the patients suggests that they may have diedon the aircraft (cases indicated with an asterisk inTable 13). This implies that more passengers may dieonboard airplanes than are reported each year.

The fatality rate was 0.107 fatalities per millionenplanements. This rate is about one-third of thatfound in similar studies. Of the 120 International AirTransport Association (IATA) member airlines, 42airlines reported a total of 577 in-flight deaths be-tween 1977 and 1984 averaging 0.31 fatalities permillion enplanements (Airline Transport Associa-tion, 1998). A 1996 Qantas study reported a fatalityrate of 0.38 per million enplanements (Donaldson &Pern, 1996). The comparatively lower in-flight deathrate in this study might be due to two factors: (1) thedata were limited to US domestic flights that mighthave been able to divert in less time than many of theIATA or Qantas flights, which were mostly interna-tional flights, and (2) all MedAire flights were man-aged by an air-to-ground radio patch with anemergency room physician, which should have re-sulted in an improved outcome.

The Airline Transport Association (ATA) reported42 in-flight deaths in 1996 (Airline Transport Asso-ciation, 1998). Adjusting for the size of the ATAsample, which represented approximately 90% of USdomestic enplanements for that year, yields an indus-try-wide in-flight death rate of approximately 47fatalities per year. Assuming the experience of the fiveMedAire companies in this study could reasonably beconsidered representative of the airline industry atlarge, and adjusting for sample size, an industry-widerate of approximately 75 in-flight fatalities per year isderived. The disparity in the number of deaths be-tween the two studies is probably due to reporting

16

differences. The ATA study only accounted for indi-viduals who were pronounced dead on the aircraft oron the jetway while, in the current study, individualswho were pronounced dead in-flight and post-flightat the gate, in transit, or at the hospital were included.In fact, only three cases would probably have beenreported as fatalities in the current study if datacollection had been limited to individuals who ex-pired aboard the aircraft. The other twelve cases weredetermined from information collected during fol-low-up.

Only four out of the 15 fatal cases were divertedimplying a flight diversion rate for fatalities of 27%.In a similar study Cummins (Cummins et al. 1988)found a diversion rate for in-flight fatalities of only14%, citing the unavailability of diversion locationson international flights as a possible explanation.This unavailability could account for the differencein rates, as all flights in this study were US domesticflights with many suitable diversion locations avail-able. It may not be unusual that 11 out of 15 fatalcases were not diverted. Although each patient wasofficially pronounced dead at the gate or at a latertime, it appears that at least some may have actuallyexpired onboard the aircraft, and a diversion mightnot have been indicated in these cases. In other cases,the destination may have been as close as any suitablediversion location, or the medical facilities at thedestination may have been better than those availableat a diversion city.

The most common cause of death in-flight wascardiac (12 of 15, or 80%), followed by pre-existingmedical conditions (2 of 15, or 13%). Cummins(Cummins et al. 1988) also found cardiac deaths tobe the most common (56%), followed by deaths dueto pre-existing medical conditions (19%), while aQantas Airlines study (Davies & Degotardi, 1982)listed myocardial infarction as the leading cause ofin-flight death (11 of 25, or 44%), followed bycerebral vascular accident (2 of 25, or 8%).

Potential Additions to the Medical Kit. Our studyindicated bronchodilator inhalers, oral antihista-mines, and non-narcotic analgesics were used fre-quently enough to suggest including them in themedical kit to deal with several common in-flightmedical events. While Cotrell et al. (1989) alsoconcluded that a bronchodilator inhaler should beadded to the medical kit, Thibeault (1998) suggestedthe addition of a bronchodilator inhaler, an antihis-tamine, and an analgesic, among other items.

In addition, oxygen, supportive care, and close pa-tient monitoring were associated with an improvementin patient condition. Good medical practice shouldinclude oxygen therapy when a bronchodilator is used,especially given the mildly hypoxic cabin environment.For example, the oxygen saturation of a normal indi-vidual at a cabin altitude of approximately 8000 feet isabout 85%. While the majority of patients who receivedboth bronchodilator and oxygen therapy improved,there were not enough cases that did not receive oxygenwith bronchodilator therapy to analyze.

Comparison of In-flight and Hospital DischargeDiagnostic Categories. There was good overall agree-ment between in-flight and post-flight diagnostic cat-egories. This agreement suggests that in-flight diagnoseswere generally accurate, even under the difficult condi-tions encountered onboard aircraft. However, the datasuggest that non-neurological cases were over-diag-nosed as neurological cases in-flight, and vascular casesappeared to have been under-diagnosed and attributedto other causes in-flight.

Severity of In-flight Medical Events. As was previ-ously discussed, there was no independent means ofdetermining the severity of cases. Unless patients cansuccessfully be grouped by severity, it may not bepossible to completely evaluate in-flight medical caredelivery, or understand the role of medical kit use,patient response, diversions, or other important ques-tions. At this point, it can only be said that in-flightmedical care and medical kit use have a significantrelationship to patient response that appears to beconfounded by the severity of the event.

CONCLUSIONS

Data collection was limited to airlines contractingwith MedAire, Inc. and may not be representative ofmedical incidents occurring on other airlines. Whileconclusions about the airline industry in general arespeculative, this study contains valuable data because itrepresents a systematic attempt to follow patients fromthe air transport system into the healthcare system.

The frequency of in-flight medical incidents was lowwhen compared with similar studies; however, the truerate may actually have been greater because cases notserious enough to warrant an air-to-ground radio patchwere not included. Cardiac events were the most com-mon serious in-flight medical incidents and accountedfor the greatest percentage of aircraft diversions formedical reasons.

17

Although the fatality rate included passengers whoexpired after removal from the aircraft, cases werelimited to domestic flights that were managed by air-to-ground communication with a physician, whichcould explain the lower fatality rate found in thisstudy compared to earlier studies; however, the ratewould have been even lower if only passengers thatdied onboard were included. In addition, the diver-sion rate for fatalities is about double the rate for non-fatal events, probably because fatal cases were generallymore serious and required a flight diversion moreoften than non-fatal cases.

In-flight diagnoses were in close agreement withhospital discharge diagnoses, and patients’ condi-tions generally improved, implying that in-flightmedical care delivery aboard US domestic air carriersis generally well managed. However, there did notappear to be a significant difference between patientimprovement and the presence or absence of a physi-cian onboard.

The data suggest that oxygen, supportive care, andclose patient monitoring were associated with an im-provement in patient condition. The data also supportthe addition of a non-narcotic oral analgesic, a bron-chodilator inhaler, and an oral antihistamine to themedical kit. These items have been recommended inother studies and are currently carried by several inter-national air carriers. Unfortunately, due to the poorresponse to certain questions by onboard care givers,this survey could not address potential medical kit itemsthat are frequently needed for relatively common condi-tions but are rarely available because they are not rou-tinely carried by other passengers.

RECOMMENDATIONS

Using the criteria adopted in this study, the itemsthat should be considered for possible addition to afuture medical kit include a non-narcotic oral analge-sic, a bronchodilator inhaler, and an oral antihista-mine. Since these data were collected from airlinesthat did not have cardiac defibrillators onboard, norecommendations are presented regarding the valueof adding cardiac medications to the kit that could beused to support an onboard defibrillator. The in-flight medical kit should be re-evaluated oncedefibrillators become widely available on US domes-tic air carriers to determine additions to the kit thatwould be appropriate to support the use of automaticexternal defibrillators.

If the impact of in-flight medical care delivery andmedical kit use is to be fully analyzed, it may benecessary to design a voluntary study to include alarger segment of the air transport industry. Onemethod of facilitating data collection might be toinclude an event reporting form in the medical kit, tobe completed at the time of the incident. If this is notpossible, mandatory reporting might be necessary; how-ever, our experience (DeJohn, Véronneau, & Hordinsky,1997), is that voluntary cooperation is superior tomandatory reporting and yields better results.

REFERENCES

Federal Aviation Administration. (1986). Emergencymedical equipment requirement; final rule, Wash-ington, DC, Federal Register 51(6): 1218-23.

Speizer, C., Rennie, C.J., & Breton, H. (1989). Preva-lence of in-flight medical emergencies on com-mercial airlines. Ann of Emerg Med 18, 26-9.

Cottrell, J.J., Callaghan, J.T., Kohn, G.M., Hensler,E.C., & Rogers, R.M. (1989). In-flight medicalemergencies. JAMA. 262(12), 1653-6.

Cummins, R.O., & Shubach, J.A. (1989). Frequencyand types of medical emergencies among com-mercial air travelers. JAMA, 261(9), 1295-9.

Rosenberg, C.A., & Pak, F. (1997). Emergencies in theair: Problems, management, and prevention. JEmerg Med, 15(2), 159-164.

Prew, S.J. (1997). Defibrillators – the pressure is on.Cabin Safety Update, 3, 1-2.

Rodenberg, H. (1987). Medical emergencies aboardcommercial aircraft. Ann of Emerg Med 16(12),1373-7.

Cummins, R.O., Chapman, P.J.C., Chamberlain, D.A.,Shubach, J.A., & Litwin, P.E. (1988). In-flightdeaths during commercial air travel. JAMA.259(13), 1983-8.

Hordinsky, J.R., & George, M.H. (1991a). Utilizationof emergency kits by air carriers. Federal AviationAdministration, Office of Aviation Medicine,Washington, DC, Technical Report No. DOT/FAA/AM-91/2.

18

Hordinsky, J.R., & George, M.H. (1991b). Responsecapability during civil air carrier in-flight medicalemergencies. Federal Aviation Administration,Office of Aviation Medicine, Washington, DC,Technical Report No. DOT/FAA/AM-91/3.

DeJohn, C.A., Véronneau, S.J.H., & Hordinsky, J.R.(1997). In-flight medical care: an update. FederalAviation Administration, Office of Aviation Medi-cine, Washington, D.C., DOT/FAA/AM-97/2.

Austin, S. (1997). [Passenger enplanements for 1996]Unpublished raw data from FAA, AFS-1.

Airline Transport Association (1998). ATA completesin-flight medical study. ATA Press Release No. 4.1-14-98.

Harding, R.M., & Mills, F.J. (1993). Medical emer-gencies in the air. In Aviat Med (pp. 7-24). Lon-don: BMJ Publishing Group.

Davies, G.R., & Degotardi, P.R., (1982). In-flightmedical emergencies. Aviat Space Environ Med53(7), 694-700.

Schoken, V., & Lederer, L.G. (1970). Unscheduledlandings for medical reasons. A five year survey ofthe experience of American Airlines. In: D.E.Busby (Ed.), Recent advances in aerospace medi-cine. Proceedings of the 18th International Congressof Aviation and Space Medicine (pp 126-9).Dordrecht, Netherlands: Reidel Publishing.

Kahn, F. (1996, July 6 & 7). We have an emergency –is there a doctor on the flight? Financial Times.pp. 12.

Mills, F.J., & Harding, R.M. (1983). Medical emer-gencies in the air. Br Med J (286), 1204-6.

Hays, M.B. (1997). Physicians and airline medicalemergencies. Aviat Space Environ Med 48(5), 468-70.

Centers for Disease Control Website (1999). http://www.cdc.gov/nchswww/. US hospital utilization,average length of stay in days. Accessed July 30,1999.

Donaldson, E., & Pearn, J. (1996). First aid in the air.Aust. N.Z. J. Surg. 66, 431-4.

Thibeault, C. (1998). Emergency medical kit for com-mercial airlines. Aviat Space Environ Med 69(11),1112-3.

A1

APPENDIX A

Kit Item Frequency PercentSphygmomanometer 522 46.1Stethoscope 518 45.8Nitroglycerin 45 4.0Syringes and needles 17 1.5Diphenhydramine 9 0.8Epinephrine 8 0.7Dextrose 4 0.4Airways 0 0.0

Table A-1 . Frequency of Use of Medical Kit Items for Five AirCarriers Over a 12 Month Period.

Item Frequency PercentOxygen 659 58.2Supportive therapy 462 40.8Monitor 409 36.1Analgesic 46 4.1Nitroglycerin 38 3.4Bronchodilator inhaler 18 1.6Oral antihistamine 11 1.0Anti-acid 9 0.8Other 7 0.6Anti-coagulant 6 0.5Narcotic analgesic 5 0.4Benzodiazepines 4 0.4Hyperglycemic 3 0.3Hypoglycemic 3 0.3Anti-emetic 2 0.2Diuretic 2 0.2Anti-arrhythmic 1 0.1Topical antihistamine 1 0.1Vasodilator, other 1 0.1

Table A-2 . Frequency of Use for Medical Items not in Kits.

A2

List A-1. Information Provided by MedAire

Radio patch numberDate of eventAircraft typeOriginDestinationCompany station (Whether the diversion airport hadfacilities operated by the airline.)Age of patientGender of patientPresentation (Signs and symptoms.)In-flight diagnosisMedical historyMedication historyIn-flight treatmentMedical personnel on boardIn-flight medical kit use (Whether or not the in-flightmedical kit was used.)In-flight medical kit userIn-flight medical kit items usedRespirationsPulseBlood pressureItems that could have been used but were not availablein the in-flight medical kitRecommendations for medical kit changesOverall patient response in-flightCategory of medical response waiting at gate (i.e.,ACLS, BLS, etc.)Patient response to medical care at gateOutcomeNarrativeDischarge diagnosisDiversion (Whether the flight diverted and diversionairport.)Diversion status (Whether or not the diversion wascoordinated by MedAire.).

List A-2. Data Coded by CAMI

GenderPatient presentationIn-flight diagnosisIn-flight diagnostic categoryTreatmentIn-flight medical kit usageIn-flight medical kit items usedDiversionOutcomeDischarge diagnostic categoryAgreement between in-flight diagnostic category anddischarge diagnostic category

List A-3. CAMI Diagnostic Code Categories

Allergic reactionCardiacEndocrineEar-nose-throat (ENT)GastrointestinalNeurologicalObstetrical/gynecological (Ob-Gyn)PsychologicalRespiratoryTraumaUrologicalVascularVasovagalMiscellaneousUnknown

A3

List A-4. Treatment Code Categories

AnalgesicAnti-acidAntiarrhythmicAnticoagulantAntiemeticBenzodiazepineBronchodilator inhalerDiureticHyperglycemicHypoglycemicMonitorNarcotic analgesicOral antihistamineOxygenSupportive therapyTopical antihistamineVasodilatorOtherNot reported

List A-5. Discharge Diagnostic Code Categories

Allergic reactionCardiacEndocrineENTGastrointestinalMiscellaneousNeurologicalNot applicableNot reportedObstetrical/GynecologicalPsychologicalRespiratoryTraumaUnknownUrologicalVascularVasovagal

List A-6. Outcome Code Categories

Admitted to hospitalDays in hospitalAdmitted to intensive/critical care unitDays in intensive/critical care unitType of intensive care unitDays in intermediate care unitType of intermediate care unitAdmitted to floor/serviceDays on floor/serviceFloor service admitted toAdmitted to telemetry unitDays in telemetry unitTreated and released in airport clinicTreated and released from emergency roomMedical response canceledWho canceled medical responseRefused medical adviceFatalityWhere pronouncedMiscellaneousNot reported

A4