AMERICAN JOURNAL OF EMERGENCY MEDICINE n Volume 2, Number 6

CPR, we could expect many more long-term survi- vors.

It is argued that open-chest CPR is too expensive to be used ab’part of a routine resuscitation protocol, but the costs ‘are higher only in those patients for whom the open-chest approach is successful. The price of a Bard-Parker blade is minimal compared with the overall cost of the resuscitation team response. Each physician team member should be familiar with the simple left fourth- or fifth-intercostal space incision and direct heart massage. It is interesting to note that before Kouwenhoven and co-workers’ report,s when open-chest massage was the standard approach, the complication rate was no greater than that of today’s closed-chest technique experience.7 Empyema sec- ondary to thoracotomy in the unprepared chest oc- curred in only 10% of the survivors.8

The indications for immediate thoracotomy in car- diac arrest associated with trauma are now well ac- cepted, and most trauma centers and inner-city emer- gency departments have established effective proto- cols and training programs. A lethal complacency, however, exists on the wards and in the intensive care setting, as expressed by the view that if external mas- sage doesn’t work, nothing else will. Even when sinus rhythm is restored after prolonged external massage, ultimate survival is rare because of brain damage re- sulting from extremely low cerebral blood flows. The Beth Israel group reported patient survived the hos- pitalization when external resuscitation lasted more than 30 minutes.3 Open, direct massage in these cases

Open-chest CPR: Not Yet

The status of thoracotomy and direct cardiac mas- sage has radically changed over the past 30 years. Prior to 1960, direct cardiac massage was the standard method of resuscitating patients in cardiac arrest. The development of closed-chest techniques, however, has relegated the use of direct cardiac massage to obscu- rity. Over the past few years, articles have emerged indicating a resurgence of interest in direct cardiac massage.

There probably is a place for thoracotomy and open- chest massage in the resuscitation of patients in car- diac arrest; however, in our opinion that role has not as yet been clarified. While most animal studies show improved hemodynamics with open-chest massage, *-3 others do not.4 Redding and Cozine4 showed that ca- rotid flows and aortic pressures changed only mini- mally when open-chest cardiac massage was com- pared with closed-chest compression. The key differ-

not only doubles blood flow but also enhances aortic compression with the direction of perfusion to the brain and coronary arteries. It is time for a critical reappraisal of current hospital resuscitation practice, recalling that the 1974 CPR standards stressed the as- sessment of “sufficiently effective artificial circula- tion” as a condition for not opening the chest.‘j

L0ursR.M. DELGUERICO, MD Westchester County Medical Center Valhalla. New York

REFERENCES

1. Del Guercio LRM, Feins NR, Cohn JD, et al. A comparison of blood flow during external and internal cardiac mas-

sage in man. Circulation 1965;32 (Suppl 1):171-180.

2. Cohn JD, Del Guercio LRM. Cardiorespiratory analysis of

cardiac arrest and resuscitation. Surg Gynecol Obstet

1966;123:1066-1070.

3. Bedell SE, Delbanco TL, Cook EF, et al. Survival after car-

diopulmonary resuscitation in the hospital. N Engl J Med

1983;309:501-508. 4. Stephenson HE, Jr, Reid LC, et al: Some common denom-

inators in 1,200 cases of cardiac arrest. Ann Surg

1953;137:731-744.

5. Kouwenhoven WB, Jude JR, Knickerbocker GG. Closed- chest cardiac massage. JAMA 1060;173:1064-1067.

6. Standards of cardiopulmonary resuscitation (CPR) and

emergency cardiac care (ECC). JAMA 1974;227 (Suppl): 833-868.

7. Powner DJ, Holcombe PA, Mello LA. Cardiopulmonary re- suscitation-related injuries. Crit Care Med 1984;12:54-55.

8. Stephenson HE. Cardiac Arrest and Resuscitation. St.

Louis: CV Mosby Company, 1969.

ence between this study and others was that Redding and Cozine used small (6-12 kg) dogs. With small dogs, true cardiac or vascular compression probably occurs with closed-chest compression, and dramatic differences in the cardiac output and aortic pressures are not demonstrated with open-chest massage. Many studies, including the one from our laboratory,) used large dogs in which true cardiac compression cannot be obtained with external chest compression. In this model, improved flows and pressures are easily dem- onstrated using open-chest massage. Are humans more analogous to large dogs or small dogs? At present, there is not enough published data to answer this question. There may even be a dimorphic popu- lation in which external chest compression causes car- diac or vascular compression in some patients (as in small dogs), and produces forward blood only by in- creasing intrathoracic pressure in others (analogous to

OPEN-CHEST CPR

large dogs). If this is true, only some patients may benefit through the use of direct cardiac massage.

Very few experiments have been performed with hu- mans. Del Guercio ef afs showed that open-chest CPR significantly increased cardiac index when applied after closed-chest compression had failed with 11 pa- tients. However, the mean systemic arterial pressures did not significantly increase with the use of open- chest massage. It is important to remember that not all improved hemodynamic parameters have corre- lated with successful resuscitation. While enhanced aortic and coronary perfusion pressures (aortic minus right atria1 diastolic pressure) have been correlated with successful resuscitation, improved cardiac index has not.6-9 Thus, the significance of an improved car- diac index in one study of open-chest CPR performed in humans may be less important than the lack of im- provement in the mean arterial pressures.

Furthermore, new techniques are being tested in many laboratories that show improved aortic diastolic and coronary perfusion pressures without the use of thoracotomy and direct cardiac massage. These in- clude some forms of simultaneous compression and ventilation,iO high-frequency, high-momentum com- pression,” CPR vest (Niemann JT. unpublished data), and intermittent abdominal compression.i2 It would make more sense to investigate these promising and less invasive techniques before thoracotomy and di- rect cardiac massage is recommended for general use.

We agree that open-chest massage is indicated when the chest is already open or when there has been pen- etrating thoracic trauma. For patients with massive pulmonary embolus or deep hypothermia, the data are so scant that firm conclusions cannot be reached. Our major concern relates to the indications for open-chest massage in the majority of cardiac arrests. The only hemodynamic parameters that have been shown in an- imals to correlate with survival are the aortic diastolic and coronary perfusion pressures. Palpable impulses over the carotid or femoral area have not been cor- related with adequate aortic diastolic or coronary per- fusion pressure, Palpable impulses are manifestations of the pulse (systolic minus diastolic) pressure, the significance of which is speculative. We do not have good, noninvasive clinical parameters reflecting cor- onary perfusion and resuscitability. Suspicion of a long arrest-time is another questionable indication for open-chest CPR. We have recently completed a series of experiments on the use of open-chest CPR in the animal model. We demonstrated that when thora- cotomy and open-chest CPR is performed after 15 min- utes of cardiac arrest with inadequate CPR, improved resuscitation rates can be obtained. Yet, when open- chest CPR is initiated at 25 minutes of arrest with in- adequate CPR, resuscitation rates are not improved through the use of thoracotomy and direct cardiac massage. This lack of success occurs despite similar

increases in aortic and coronary perfusion pressures with open-chest CPR at 15 and 25 minutes.

We are concerned that if practicing emergency phy- sicians begin performing thoracotomies on patients with little or no chance of cardiac or cerebral resus- citation, open-chest massage will again be condemned without an adequate trial. More human and animal research should be done to sort out those patients with a good chance of responding to open-chest CPR. To recommend the general use of open-chest CPR at the present state of CPR knowledge is, in our opinion, premature. Research trials shouid be performed under the scrutiny of institutional review boards to protect the patients. Furthermore, studies with both animal models and humans should be undertaken to evaluate methods of determining the adequacy of CPR. Finally, these research projects must take into account the other less invasive techniques currently being evalu- ated that may improve essential hemodynamic param- eters and obviate the need for thoracotomy.

ARTHUR B. SANDERS, MD GORDON A. EWY, MD University of Arizona Tucson, Arizona

REFERENCES

1. Bircher N, Safar P, Stewart R. A comparison of standard,

MAST augmented and open chest CPR in dogs. Crit Care

Med 1980;8:147-152.

2. Bircher N, Safar P. Comparison of standard and “new”

closed chest CPR and open chest CPR in dogs. Crit Care

Med 1981;9:384-385.

3. Sanders AB, Kern KB, Ewy GA, et al. Improved resuscitation

from cardiac arrest with open chest massage. Ann Emerg

Med 1984;13:672-675.

4. Redding JS, Cozine RA. A comparison of open chest and closed chest cardiac massage in dogs. Anesthesiology

1961;22:280-285. 5. Del Guercio LR, Feins NR, Cohn JD, et al. Comparison of

blood flow during external and internal cardiac massage

in man. Circulation Supplement 1965,1,31-2:1171-180. 6. Ditchey RV, Winkler JV, Rhodes CA. Relative lack of coro-

nary blood flow during closed-chest resuscitation in

dogs. Circulation 1982;66:297-302.

7. Halperin HR, Tsitlik JE, Guerci A, et al. Optimization of myo-

cardial and cerebral flow during cardiopulmonary resus-

citation (abstract). J Am Coll Cardiol 1984;3:595.

8. Ralston SH, Voorhees WD, Babbs CF: Intra-pulmonary epi- nephrine during prolonged cardiopulmonary resuscita-

tion: Improved regional flow and resuscitation in dogs.

Ann Emerg Med 1984;13:79-86. 9. Sanders AB, Ewy GA, Taft TV. The prognostic and thera-

peutic importance of the aortic diastolic pressure in re- suscitation from cardiac arrest. Crit Care Med 1984 (in

press).

10. Rudikoff MT, Maughan WL, Effron M, et al. Mechanisms of blood flow during cardiopulmonary circulation. Cricula-

tion 1980;61:345-352. 11. Newton JR, Glower DD, Wolfe JA, et al. Quantitative com-

parison of several methods of external cardiac massage

(abstract). J Am Coll Cardiol 1984;3:596. 12. Ralston SH, Babbs CF, Niebmer MJ. Cardiopulmonary re-

suscitation with interposed abdominal compression in dogs. Anesth Analg 1982;61:645-651.