International Journal of Clinical Monitoring and Computing 13:191-206, 1996. 191

Abstracts of the Seventeeth Annual Conference on Computers in Anesthesia, New Orleans, Louisiana, October 23-26, 1996

Sponsored by the Society for Computers in Anesthesiology (SCIA)

Symposium Director and President of SCIA: Bradley E. Smith, M.D. Abstracts Editor: Darel G. Hess, Ph.D.

1. Anesthesia workload in present Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Ken Asayama

2. Collaborative hypermedia development: an emerging paradigm for academic collaboration . . . . . . . 194 Michael T. Bailin & Bryan P. Bergeron

3. An anesthesia method for patient arousal and mapping of motor and speech areas during craniotomy for excision of left fronto-parietal and temporal tumors using a computer-guided pointer showing a three-dimensional view of tumor from magnetic resonance images . . . . . . . . . . . . . . . . . . . . 194 J.A. Barwise, L. Berman, K. Clarkson, O.K. Chung & R.J. Macunias.

4. Guarding your intellectual property rights in the era of electronic publishing . . . . . . . . . . . . . . . . . . . . . . 195 Bryan P. Bergeron & Michael T. Bailin

5. Implementation issues for automated anaesthesia record systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 Philip Cumpston

6. Nonlinear regression analysis of human body surface area data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 John D. Current

7. Feedback mechanisms of the cardiovascular system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Michael Danielsen

8. Use of the Internet for patient medical record transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 Gordon L. Gibby & Sam Campbell

9. Availability of medical records to the outpatient preanesthetic clinic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 Gordon L. Gibby, Wilhelm K. Schwab & Richard Goede

10. Validation of the BreathSim breathing circuit simulator using a neural network-based capnogram analysis algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Julian M. Goldman & Denham R. Ward

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11. Demographics of anesthesiologists who use the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 John Oyston & John Ascah

12. Placement o fa Surgi-Server generated OR schedule on a Web page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 Robert W. Phelps & John Lockrem

13. The computerized anesthesia record: quality assurance and medicolegal perspectives . . . . . . . . . . . . . 202 David L. Reich

14. Intraoperative hemodynamics and mortality following coronary artery bypass surgery . . . . . . . . . . . 203 David L. Reich, Carol Bodian, Aleksandar Timcenko, Kaya Sarier & Steven Lansman

15. Thirty-five years with a computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 N. Ty Smith

16. An interactive hypermedia program to review pulmonary physiology and the effects of general anesthesia on normal pulmonary physiology and the patient with pulmonary co-existing disease .. 205 Jonathan P. Yim, George J. Sheplock & Simon C. Hillier

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1. Anesthesia workload in present Japan

Ken Asayama A former member of the Committee, The Japan Society of Anesthesiology, ASA Anesthesia Office, 703-7, 39-1, Tosimaku, Tokyo, 170 Japan

Introduction. We are experiencing a shortage of anesthetists. Under advice of the Industrial Medical Labor Institute of the Labor Ministry, a committee of the Japan Society of Anesthesiology surveyed the shortage using a formula incorporating OR activities.

Method. We requested anesthesia OR reports from 59 major hospitals in Japan, of which 33 hospitals provided us with their human resources data based on daily department records in September 1995. We analyzed the data with MS-Excel.

Results. Results of the survey are summarized in table 1. Thirty- three hospitals provided data on their anesthesia practice which included dates o f service, onset and end of anesthesia times, names of the anesthetists, and names of the surgeries. Using the Excel analysis tools, we summarized the personal OR attending dates (attending or not), anesthesia performing times, and average total time of each individual anesthesia in a given day. We calculated their daily anesthesia occupation hours, with mean anesthesia time from their first anesthesia to their last emergence.

There are 328 anesthetists in our survey, and 138 persons who provide anesthesia and worked at least five weekdays in their hospitals. The anesthetists worked an average of 96 hours in a month both performing anesthesia and occupation times. Maximum times are 275 hours in performing anesthesia and 199 hours in occupation.

Other types of attending anesthetists who worked from one to four days weekly, worked from 0.38 to 73 hours performing anesthesia and from 0.38 to 82 in occupation. Five-day and four-day anesthetists are similar in daily work load. The other three types of anesthetists show less effectiveness in daily work load.

Lastly, we report on anesthetists who are present only occasionally. There are 61 such physicians in the report. An acute shortage of anesthetists in the hospitals necessitates surgeon's aids to meet the needs of the patients on the anesthesia practice.

Conclusion. A monthly average of 96 hours performing anesthesia means five hours of anesthesia practice daily. At least three hours are needed for anesthesia induction, emergence care and pre-operative patient visit.

Table I. Survey Summary

Personal Weekly Attending Day(s)

1 2 3 4 5 Occasional Total Anesthetists Number

Monthly Anesthesia Performance Hours No. Of Anesthetics 43 Average Anesthesia Hours 0.38 Minimum Performance Anes~esia Hours 23 Maximum Performance Anesthesia Hours 8 STDEVP 6

Monthly Anesthesia Occupation Hours No. Of Anesthetics 43 Average Anesthesia Hours 0.38 Minimum Performance Anesthesia Hours 26 Maximum Performance Anesthesia Hours 8.0 STDEVP 5.9

20 19 47 138 61 3 40 73 96 34

36 12 25 8 0.8 20 132 149 275 169 10 36 30 48 45

20 19 47 138 61 3 39 82 96 40

41 12 31 8 0.75 22 113 257 199 231 11 30 47 40 51

328

328

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2. Collaborative hypermedia development: an emerging paradigm for academic collaboration

Michael T. Bailin & Bryan E Bergeron Harvard Medical School & Massachusetts General Hospital, Dept. of Anesthesia, Fruit Street, Boston, MA 02114, USA

Amid the maelstrom of massive medical re-engineering pressures, a downward spiral in applications for anesthe- siology residencies, and the increasing demands on personal time outside of the OR, academic anesthesiologists must contend with the need to educate their residents and students and to keep abreast of changes in the field. Fortunately, the exponential growth in information technologies, especially those related to the World Wide Web and CD-ROMs, has made it tenable for most academic anesthesiologists to address these seemingly orthogonal goals. As information resources, electronic modalities of information dissemination, when properly executed, can provide anesthesiologists with extremely timely information in an efficient, effective, and intuitive manner. As pub- lishing media, CD-ROMs and the Web provide opportunities for embellishing otherwise dry textual descriptions with engaging and informative simulations, sounds, video sequences, and high-resolution graphics. Publishing for digital media, however, requires a significant paradigm shift in the way that authors, editors, academic departments, and publishers work and interact.

In the planning and development of the Harvard Anesthesia Electronic Compendium CD-ROM, we discovered a number of significant issues related to electronic publishing versus paper publishing that should be of interest to any academician entertaining a similar project, including: 1) The management of an electronic publication effort is much more resource intensive, in part because of the larger number of specialists that must be involved, e.g., not only must editors deal with textual submissions, but audio, video, simulations, and a variety of graphic elements must be cataloged, evaluated, and edited; 2) Copyright assignment and ownership is much more complicated, e.g., with the option for self-publishing on the Web, many authors are no longer willing to simply assign copyright to a publisher. As such, licensing arrangements are increasingly popular, with copyright remaining with the department or author; 3) Negotiations with publishers are much more involved. Given the ease with which content can be repurposed, there is a tension between the publisher's desire to secure all rights to content versus the authors desire to use their content in other publications; 4) Authoring and editing a hypermedia work requires a new skill set. Not only must authors and editors contend with the review of text, image, sound, and video Submissions, but this content must be linked in a manner that supports the pedagogical goals of the work. Hypermedia linking is a skill that takes time and commitment to learn and use effectively, even for seasoned authors and editors.

Although electronic publishing has made the task of information acquisition easier and more efficient, the current status of development tools, together with an overall lack of experience with the medium, places a con- siderable burden on the academic author. Given the new generation of authoring tools and technologies on the horizon, together with an increased understanding of the merits and uses of the technology, electronic publishing will become an increasingly important modality for academic collaboration.

3. An anesthesia method for patient arousal and mapping of motor and speech areas during craniotomy for excision of left fronto-parietal and temporal tumors using a computer-guided pointer showing a three- dimensional view of tumor from magnetic resonance images

J.A. Barwise, L. IJerman, K. Clarkson, O.K. Chung & R.J. Macunias. Depts. of Anesthesiology (Barwise, Berman, Clarkson, & Chung) and Neurosurgery (Macunias), Vanderbilt Uni- versity Medical Center, Nashville, TN 37232-2125, USA

Background. Resection of malignant cerebral tumors as close to the margins as possible result in prolonged life span by reducing bulk and pressure effects. The left brain tumor margins are close to vital structures and pathways that would detract from quality of life. Speech and motor function mapped prior to excision by a precision computer

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guidance system allows for greater bulk resection and better morbidity outcomes. The technique requires the head frame application to be rigidly fixed to the operating table. The patient is required to be fully alert and conversing for the mapping and tumor resection. This results in a multitude of anesthetic difficulties.

Method. Pain relief is provided by local anesthesia and supplemented on the table during the awake testing phase with 25-50 microgram boluses of alfentanil. All surgical sites including the frame pins and the urinary catheter are instilled with local anesthesia. The total local anesthetic dose is calculated and utilized. Patient comfort is provided for by two eggshell foam rubber mattresses and a whole-body air-blanket warmer. Airway management is different in three distinct periods. At first the patient requires head frame application positioning and then craniotomy with the dura reflected. The airway is provided by an LMA (laryngeal mask airway) and anesthesia by total intravenous anesthesia with Diprivan | This period lasts until the opening of the dura whence the patient is aroused in a graded fashion with diprivan decreased to levels of 30 to 5 micrograms per kilogram per minute. The LMA that is placed under sphenopalatine, superior laryngeal and glossopharyngeal nerve blocks and analgesia tested by awake insertion in the holding room. The second phase is when the patient is ready for awakening and motor and speech testing. The airway is provided by a nasal trumpet airway inserted during the first phase. The second phase may last until the tumor is resected. This allows for testing to see if the deeper resection leaves the brain structures intact. The final phase is the wound closure when the patient is anesthetized with diprivan and the LMA is reinserted and ventilation instituted. All airway procedures are constantly monitored with video fiber optic laryngoscopy to ensure any aspiration is detected early and treated.

Results. Eleven awake, left-sided craniotomies have been performed so far with good functional outcomes. Two patients had aspirations for which they were intubated and electively ventilated post operatively for 24 hours without problems. Four patients have neurological deficits lasting more than seven days and are improving with physical rehabilitation.

4. Guarding your intellectual property rights in the era of electronic publishing

Bryan P. Bergeron & Michael T. Bailin Harvard Medical School & Massachusetts General Hospital, Dept. of Anesthesia, Fruit Street, Boston, MA 02114, USA

The immediacy, potential cost effectiveness, and increasing market acceptance of electronic publishing are attracting an increasing number of anesthesiologists to this mode of communications. However, while authors may approach, for example, a CD-ROM publication just as they would traditional journal and book contributions, publishers, and copyright attorneys view digital works in an entirely different light. In negotiating copyright agreements, unsavvy authors may not only loose personal intellectual property rights, but those of their current and future colleagues as well. As authors, we have an obligation to become just as fluent with the intellectual property issues associated with electronic publishing as we are with that of print media.

Electronic contributions differ from print publications in a number of significant aspects. Firstly, digital images and text are much more easily repurposed for unauthorized use than are printed materials. With the appropriate utilities, content in a CD-ROM, for example, can be quickly and effortlessly extracted to become part of a printed document or a documenf on the World Wide Web. Secondly, unlike print authors, authors of digital works generally contribute more than static text, graphs, photographs, and a few keywords. When developing a medical hypermedia publication, an author may spend considerable intellectual energy in determining how to best provide hyperlinks between clinically related terms, images, and video sequences, in determining which pedagogical perspectives to support, and how to provide for ancillary content.

In our experience working with medical publishers over the past decade, it seems that, after a considerable latency period, even the most conservative publishers are pouring enormous energy into mastering digital media-- and into acquiring all conceivable rights to digital information, including how content is linked, the method of

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access, and other details that have escaped their attention in the past. In addition, because self-publishing is now commonplace, the potential for competition from a self-published author that has also published through a publisher is more tenable. Publishers are, in general, attempting to limit an author's ability to disseminate his or her own information in any form that may interfere with sales of their offerings of the same author's works. This attempt to limit competition commonly extends to the departmental and institution level. Publishers have even gone so far as to attempt to acquire all intellectual property rights to publications on a topic from within a department for years.

Without careful, coordinated negotiation with your department and potential publisher, it is possible to forfeit the publishing rights of not only your current colleagues, but your future colleagues as well. We suggest that every author invest the time to read about and understand the intellectual property issues related to CD-ROMs, the World Wide Web, and all other forms of electronic publishing.

5. Implementation issues for automated anaesthesia record systems

Philip Cumpston Division of Anaesthesiology and Intensive Care, The University of Queensland/RoyaI Brisbane Hospital, Brisbane, Australia

In 1992, N. Ty Smith stated that 'The anaesthetic information system, including the automated anaesthetic record (AAR), appears to be an idea whose time has come' (N. Ty Smith, Computing and Monitoring in Anaesthesia and Intensive Care - Recent Technology Advances, Springer Verlag 1996, p 265). Since then, automated anaesthesia record keeping systems have been implemented in a variety of ways, with varied success. The Arkive| system, which led the way for many years is no longer supported by the manufacturer.

In the process of tendering for the purchase of new anaesthesia machines and monitors, an additional tender specification document relating to anaesthesia information systems was drawn up and circulated widely. This document laid out the key components of an anaesthesia clinical information system. It was felt that the primary goal of this system would be to provide a clear, concise and comprehensive record of clinical events during anaesthesia, displayed in an easily understandable format and enabling the anaesthetist to focus on the patient, as well as reducing the incidence of transcription errors. Other aspects of the system, such as the automation of clerical tasks and improved productivity of clinical, administrative and research staff were touched on.

Copies of this document are available from the author on request. When we upgraded our anaesthesia monitoring systems and our anaesthesia machines in 1995, the successful

company entered into a partnership agreement to further develop their existing anaesthesia information management system on site in our hospital to incorporate our specifications and ideas. To this end, a senior systems engineer was appointed to work in our department for the duration of the project.

The process of installing this system required the following: �9 Development of a management/implementation plan

�9 Development of a research plan, to highlight the information required �9 Design of reports, the AAR �9 Infrastructure development and acquisition

�9 data entry systems

�9 the anaesthetic monitor and keyboard input

�9 development of lookup tables and menus to speed data entry

�9 dedicated software development computer with laser printer and network card �9 computer workstations for reporting and to control data transfer to and from the anaesthesia information

center �9 installation of a dedicated local area network (LAN) and server ( the Anaesthesia Information Center - AIC)

�9 interface to the hospital LAN �9 office facilities for the development engineer

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�9 Evaluation of the system as it was developed by the staff that would be using it, education, training, and acceptance testing.

�9 Quality assurance �9 data integrity testing �9 development of data backup systems

We are still in the process of installing this system, and plan to have it fully operational by the end of 1996. During the process of installing hardware and software, many inefficiencies were encountered and some mistakes were made. These will be highlighted during the formal presentation, and a progress report will be given.

6. Nonlinear regression analysis of human body surface area data

John D. Current Dept. of Anesthesiology, University of Mississippi Medical Center, Jackson, MS 39216, USA

Introduction: Determination of human body surface area from height and weight is useful in surgical metabolic- related calculations such as oxygen consumption, fluid requirements, or drug doses. The availability of modem digital computers with appropriate software make possible the fitting of a nonlinear function for human body surface area data.

Method: Published human body surface area and associated height and weight (HBSAD) data were subjected to non-linear regression analysis on an MS-DOS-based computer using an adaptive non-linear least squares algorithm.

Results: The data were found to fit a biexponential model: Area -- 0.01281 x Weight .4471 x Height .5942 Area is in meters squared; weight is in kilograms; and height is in centimeters. The correlation coefficient (R) is .9944. The probability that any of parameters is actually zero is less than .001 (T test) and the probability that the relationship is actually random is less than .001 (F test).

Conclusion: The expression: Area = 0.01281 x weight .4471 x height .5942 closely approximates published HBSAD. Because of the ease of programming computers and hand-held calculators, this expression should be easily adapt- able for clinical utility.

7. Feedback mechanisms of the cardiovascular system

Michael Danielsen Dept. of Mathematics and Physics, Roskilde University, Postbox 260, DK--4000, Roskilde, Denmark

The Department of Mathematics and Physics at Roskilde University, Denmark is participating in the develop- ment of an anesthesia simulator. The existing simulator is applied to the training and education of anesthetists and anesthetic nurses. This presentation gives an introduction to the simulator and its perspectives. The simulator devel- opment involves modeling of the cardiovascular system, baroreceptor regulation, the respiration system, kinetics and the dynamics of O2/CO2 and anesthesia. The main focus of the presentation is on the modeling of the cardio- vascular system and the control actions from the baroreceptor mechanism. The cardiovascular system is controlled by sympathetic and parasympathetic nervous signals which are strongly influnced by baroreceptor reflexes from the aortic arch and the carotid sinus. One mathematical approach in the description of the baroreceptor mechanism distinguishes between the sympathetic and parasympathetic nervous signals. This makes it possible to simulate and alter the influence of the sympathetic and parasympathetic signals on the cardiovascular system. The mathematical model accounts for the efferent influence on the heart rate, peripheral resistance, venous capacity, and myocardial contractility. Simulated infarcts and hemorrhages are used to test the mathematical model. Several attempts have

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been made in order to set up mathematical models of the cardiovascular system and the control action from the baroreceptor mechanism. These models have different degrees of complexity and serve different purposes. This leads to the discussion of the model principles and introduction of pulsatile or non-pulsatile models.

8. Use of the Internet for patient medical record transmission

Gordon L. Gibby & Sam Campbell Dept. of Anesthesiology, University of Florida, School of Medicine, Gainesville, FL 32610-0254, USA

Introduction: As Americans become increasingly mobile and advanced in age, the incidence of patients presenting for surgery away from the institution(s) maintaining one or more pertinent past records will increase. The Internet provides a possible medium for transmission of such records through specialized communications systems. We examined the legal implications of electronic medical records transmissions over the Internet and searched for means to standardize such transactions.

Method: We examined state and federal legislation and case law regarding the use of public networks such as the Internet for communication of medical records. We then developed a proposed 'contract' that would standardize such transactions to meet Joint Commission on Accreditation of Healthcare Organizations, state and federal requirements.

Results: Existing laws regarding property can be applied to Internet computers, but questions of jurisdiction still remain for issues of crimes and practice. Signatures providing nonrepudiation are a key requirement for patient release of information. Patient rights of privacy, having basis in both specific legislation and common law, place restrictions on physicians and health care institutions, effectively requiring documented patient permission and reasonable standards for protection of privacy. Application of existing cryptographic protocols may be helpful but can be difficult due to the problems of user authentication which remain. Multiple laws criminalizing the unauthorized interception of confidential information provide some deterrence, but developers still have significant responsibilities. Proposed federal legislation will improve the patchwork quilt of state laws, but imposes additional problems of notification. A contractual agreement provides a method of defining a 'reasonable standard.' An encrypted patient release using cryptographic digital signature of the health care personnel and witnessed signature of the patient may be sufficient for patient medical record release. A double level of encryption (provider, institution) in both directions allows for the necessary audit trails and protection of patient information.

Conclusions: The economic and patient-care advantages of easy access to medical data will drive the system to utilize widely available communications systems. The Internet can be more secure than many methods of transmis- sion already in use today. The development of private consortium or governmental superstructure using contractual or legislated requirements for data transmission would speed the adoption of such systems.

9. Availability of medical records to the outpatient preanesthetic clinic

Gordon L. Gibby, Wilhelm K. Schwab & Richard Goede Depts. of Anesthesiology (Gibby & Schwab) and Surgery (Goede), University of Florida, School of Medicine, Gainesville, FL 32610-0254, USA

Introduction: The rise of outpatient surgery has created the outpatient preanesthetic clinic, adding new scheduling and time constraints to the preanesthetic evaluation. There are no published data on the availability of old records

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to such clinics, nor of the impact of delays in obtaining such records. We performed a pilot measurement of the availability of records and devised a measurement tool to determine the initial impact of missing records.

Methods: Clerical staff in the outpatient preanesthetic clinic were requested to fill out a simple questionnaire on each patient, answering four questions:

1. Were you able to get a hospital chart on this patient?

2. Does the patient have an old hospital chart at all?

3. Was this patient's care delayed while you were obtaining a chart?

4. Did you attempt to contact another hospital or other medical office for verbal or faxed information regarding this patient?

After analysis of the collected data, a scan form was developed, using the Teleforms TM scanning system, to gather more complete data.

Results: A total of 553 forms were returned by the clerical staff from July 9 through August 11, 1993. Staff completed question one on 97% of forms, responding that a chart could not be obtained for 147/553 patients. Of the 147 patients whose charts were not available, staff indicated that for 136, a chart was known to exist, for 9 it was known not to exist. Response rates on questions on delays of care (#3) and attempts to contact other institutions (#4) were poor, 31% and 20% respectively. In part, based on these data, a new data gathering instrument for continual observation of availability of records to the clinic was developed. The improved form, using scan technology, allows clerical staff to note the existence of charts, but defers to physicians to indicate: availability of surgical history and physical information; efforts to locate records from other institutions; and delays required to find existing data, obtain new studies, or treat existing problems. As a secondary source of information, clerical staff will be asked to judge existence and cause of delays in evaluation, but physicians will be asked to enter start and stop times of evaluation.

Discussion: The pilot data indicate that for 24.6% of patients, an existing old chart cannot be obtained for the preanesthetic evaluation. Development of computerized medical record systems would be expected to improve this situation. The impact on costs of evaluation in terms of additional physician time required, or on the costs of the institution, or risks to the patient from lack of access to existing information, may be considerable but were not measured. The newly developed scan form system will provide a process monitoring tool that may be utilized by outpatient anesthesia clinics to track the problems more accurately.

10. Validation of the BreathSim breathing circuit simulator using a neural network-based capnogram analysis algorithm

Julian M. Goldman & Denham R. Ward Dept. of Anesthesiology (Goldman), Univ. of Colorado School of Medicine, 4200 E Ninth Avenue, Denver, CO 80262, & AI Technology Group (Ward), 3200 Valmont Rd. #8D, Boulder, CO 80301, USA

Introduction: Computer simulation of physiologic and mechanical systems is widely used for education and research because it can reduce the need for expensive or dangerous in vivo testing and permit the simulation of uncommon scenarios. However, the potential utility of a simulation depends on its accuracy and performance.

We have developed an interactive computer simulation (BreathSim) of the respiratory mechanics in a circle breathing circuit, and propose to assess the efficacy of BreathSim to generate morphologically accurate capnograms. BreathSim utilizes a model of the circle breathing circuit, ventilator, tracheal tube, and lungs to generate gas flow, pressure, and capnograms as changes are made to ventilator settings, unidirectional valve function, circuit integrity, and pulmonary characteristics. We can test the capnograms generated by BreathSim for accuracy by examining the capnograms with a previously developed neural network-based capnogram classification algorithm (CapWave).

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CapWave's neural networks were developed using a mechanical lung and a modified anesthesia machine, a technique which is widely used to generate clinically representative capnograms (J Clin Monit 1987; 3:194-200). Since CapWave's capnogram recognition performance is 98-100% on in vitro (mechanical lung) and limited in vivo data sets (Program of the 44th NYSSA PGA, 1990; 305), we proposed using CapWave to assess the accuracy of BreathSim's capnograms.

Methods: Circuit element parameters were adjusted in BreathSim to simulate the resistance, capacitance, and flow relationships in a standard disposable adult circle circuit, 8.0 mm ID tracheal tube, normal adult human lungs, and constant inspiratory flow ventilator. CO2 production was set to 220 ml/min, fresh gas flow to 2 L/min, I:E to 1:2, VT to 800 ml and respiratory rate to 8. The following conditions were simulated: normal, incompetent inspiratory valve, incompetent expiratory valve, increased airway resistance, and partially exhausted (25% effective) COs absorbent. For each normal and abnormal condition 30 breaths were generated. Capnograms were 'sampled' from the y-piece of the simulated circuit and saved to computer disk files. CapWave read the capnogram files and assigned each capnogram to one of 5 morphologic classifications that are characteristic of the simulated conditions. Morphologic accuracy of capnograms generated by BreathSim was determined by counting the number of capnograms correctly assigned to each classification.

Results: A total of 150 capnograms were generated by BreathSim and analyzed by CapWave. Classification accuracy was 100%.

Conclusion: CapWave's high classification accuracy verifies that capnograms generated by BreathSim were mor- phologically comparable to those generated by the mechanical lung and modified anesthesia machine which were used to develop the neural network algorithms. With further testing and validation, BreathSim may prove useful for generating capnograms (as well as other respiratory waveforms) for developing and evaluating commercial respiratory diagnostic systems.

11. Demographics of anesthesiologists who use the Internet

John Oyston & John Ascah Dept. of Anaesthesia, Orillia Soldiers" Memorial Hospital, 170 Colborne Street West, Orillia, Ontario, Canada L3V 2Z3

Introduction: Although many anesthesiologists are active Internet users, no previous study has determined which anesthesiologists use the Internet: e.g. academics or isolated rural anesthesiologists?

Method: A survey form was set up on the World Wide Web part of the Internet, and publicized by e-mail to many anaesthesia organizations, webmasters of major sites, and by repeated e-mail messages to the main anesthesiology Internet mailing lists. An e-mail version was available for those who did not have Web access.

Results: The first 119 of 205 replies are tabulated in table 1. Ninety-two percent of respondents were male, and 66% worked at university or teaching hospitals. Only four replies were received from CRNAs and none from general practice anesthetists. Replies came from 22 countries, including Brazil, Chile, India, Israel and the UAE.

Discussion: The survey group consists of those anesthesiologists who had the time and inclination to complete the survey form, and so may not be representative of all anesthesiologists who use the Internet.

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Conclusion: The survey demonstrates the international use of the Internet by anesthesiologists. Most of the users are specialist or academic anesthesiologists from large cities in North America and Europe.

Table 1. Survey Summary

Variable Number Percentage

Age Group (n=80) Under 40 39 49 40-49 28 35 50+ 13 16

Position Specialist 60 55 Academic 33 28 Training 17 14

City Size Over 1 million 47 41 20OK- 1 million 34 30

Area North America 61 52 Europe 31 26

12. Placement of a Surgi-Server generated OR schedule on a Web page

Robert W. Phelps & John Lockrem University of Colorado, Health Sciences Center, 4200 E. 9th Ave., Denver, CO 80262, USA

Surgi-Server, our OR scheduling and database program, is used to generate a daily, printed OR schedule each afternoon for the following day. This schedule, however, is not available to anesthesiologists and surgeons who are not physically located in the hospital. In order to make the following day's schedule readily available to all personnel, we decided to make it accessible from the anesthesiology department's World Wide Web (WWW) home page. Two problems confronted our attempt to accomplish this task. The first was security, i.e. we had to ensure that patient confidentiality was not violated. The second problem involved the logistics of actually transferring the information. Having solved these two problems, there is unanimous agreement among computer users that easy accessibility of this information using any computer with Internet access and a WWW browser is advantageous.

Protecting the confidential nature of patient information is essential, especially when remote access to infor- mation is available. We accomplished this in two ways. We use a Web server (Netscape Commerce Server) which (via .nsconfig files) provides access control to every file in every directory. Users are not allowed access to the information unless they know both a user name and password. Both Netscape and Microsoft Internet Explorer support passwords. Browsers without the appropriate password modules are denied access to the schedule by the server. Second, a Perl script strips off the patient names and numbers so that even if an inappropriate individual gets access to the password, no identifiable patient information can be obtained. Thus the schedule which is available via the browser contains only the OR room number, patient's age, planned procedure, times, and anesthesiologist and surgeon names. For anesthesiology purposes, these fields are sufficient until the anesthesiologist is in-house. Some surgeons have asked that patient names also be included and we are discussing ways of accomplishing this and the associated security implications. These two controls have made the technique acceptable to our hospital attorneys and all applicable hospital committees.

Obtaining and reformatting information from Surgi-Server proved to be nearly as formidable as security issues. First, we found no easy way to get information out of Surgi-Server. Indeed, the only apparent method involves printing reports. Fortunately it is possible for Surgi- Server to print a report to a file, which produces an ASCII

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text file. We trained our scheduling personnel to print the schedule to a file at the same time as they print a hard copy. Next, the schedule file is copied to the server using a semi-automated F'I'P (file transfer protocol) program. Both these tasks take little time and we found it easy to train the scheduling clerks to perform them. Access to the schedule on the server is only possible via a CGI (Common Gateway Interface) script written in Perl which reformats the schedule into an HTML table and returns it to the requestor. Changes in the schedule format require only that we change the Perl script and does not require retraining of the scheduling clerks.

13. The computerized anesthesia record: quality assurance and medicolegal perspectives

David L. Reich Associate Professor of Anesthesiology, Dept. Of Anesthesiology, Mr. Sinai Medical Center, New York, NY 10029, USA

Quality Assurance: There is little doubt that large computer- generated anesthesia record databases provide excel- lent material for quality assurance purposes. It is unfortunate, however, that software for analysis of computerized anesthesia records is not yet well developed. Quality assurance reports of cardiac arrest over 17 years in a university hospital and clinical competency in a private practice setting have been reported (Acta Anaesthesiol Scand 1988; 32:653-64, QRB Qual Rev Bull 1991; 17:182-93).

The following is an example of a quality assurance study based on computer records (Anesth Analg 1995; 80:SCA87). Pulse oximeters have been reported to fail in 1.12-2.50% of cases using handwritten anesthesia records. Case files of 21,214 computerized anesthesia records from two hospitals and 1,119 handwritten records were reviewed. The mean pulse oximetry failure rate (> 10 min duration) in computerized anesthesia records was 8.20% compared with 2.0% in handwritten records. The most significant predictors of pulse oximetry failure were age (2-12 yrs, >70 yrs), ASA physical status 3, 4, or 5, increasing duration of anesthesia, and type of surgery (e.g., orthopedic, vascular, and cardiac). Hypothermia, hypotension, and hypertension were also found to be associated with pulse oximetry failure. Thus, the objective nature of the computerized data collection provides both a realistic assessment of the limitations of the technology as well as a powerful research tool for assessing the causes of pulse oximetry failures.

MedicolegalIssues: It is debatable whether computerized records are advantageous in malpractice claims. On the basis of several studies, advocates of computerized record keeping assert that manual records are neither accurate nor contemporaneous records of vital signs (J Surg Res 1977; 22:419-24). Cook, et. al. compared 46 handwritten and electromechanically generated blood pressure records and found substantial differences (Anesthesiology 1989; 71:385-90). The highest and lowest blood pressures that were recorded automatically exceeded the highest and lowest pressures found in corresponding handwritten records, respectively. More than one-third of records had at least three automatic blood pressure determinations with values substantially in excess of the most extreme values recorded by hand, and no handwritten record contained a diastolic pressure above 110 mmHg. They concluded that these discrepancies between handwritten and automatic records may arise because of automated readings unobserved by the anesthesiologist, faulty reconstruction of handwritten records from memory, and bias in favor of less controversial values. Other studies make similar points.(Acta Anaesthesiol Scand 1988; 32:653-64, J Clin Anesth 1992; 45:386-9).

The purported medicolegal advantages of computerized record keeping may be summarized as follows: They provide an accurate time sequence of events, especially during critical incidents; The defense attorney will be able to assess the merits of a case; They will prove vigilance more often than negligence (Semin Anesth 1991; 10:41-7); and They are useful in refuting accusations of sloppiness and implied negligence.

A recent article by Zeitlin of the ASA Committee on Professional Liability argued that automated records do not reduce anesthesia liability (ASA Newsletter 1995; 59 (6):21-23). These points may be summarized as follows: It is doubtful that computer records contain better information; The key to medicolegal defense is a thoughtful

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explanation of actions in the OR; The filtering and smoothing of extreme values is of data irrelevant to outcome and appropriate in an era of 'error-blame' mentality; Pulse oximetry and capnometry are applied universally because they are useful whereas computer records have never gained wide acceptance because they are not useful; and The Closed Claims Project data do not support the role of poor anesthesia records in unfavorable malpractice claims.

14. Intraoperative hemodynamics and mortality following coronary artery bypass surgery

David L. Reich, Carol Bodian, Aleksandar Timcenko, Kaya Sarier & Steven Lansman Depts. of Anesthesiology, Biomathematical Sciences & Cardiothoracic Surgery, Mt. Sinai Medical Center, New York, NY 10029. USA

Introduction: The modulation of sympathetic responses and rigorous intraoperative hemodynamic control has never been proven to decrease perioperative cardiac morbidity (Anesthesiology 1990; 72:153- -84). The purpose of the current study is to determine whether intraoperative hemodynamic instability was associated with death in a cohort of patients undergoing coronary artery bypass grafting (CABG).

Methods: The study was institutionally approved. Risk factors and outcomes were queried from a New York State-mandated database. Intraoperative hemodynamic lability was measured (using a validated algorithm) from computerized anesthesia records that recorded data every 15 seconds. In addition, the number of minutes a patient was exposed to moderate and severe extremes of various hemodynamic variables (e.g., mean arterial pressure 130 mm Hg) was tabulated. Univariate tables and multivariate logistic regression were used to identify predictors of perioperative death.

Results: There were 687 patients and 20 perioperative deaths. All o f the deaths occurred in patients undergoing urgent or emergent surgery (n=421), and all had Canadian Cardiovascular Surgery functional status III or IV. The predictors of death are summarized in the table 1. The hemodynamic variables were not independent (multivariate) predictors of death.

Conclusions: The presumption that smooth intraoperative hemodynamics are associated with improved outcome has never been demonstrated. The data in the current cohort of patients do not support the concept that intraoperative hemodynamic instability is an independent predictor of mortality.

Table 1 Univariate and multivariate analysis of risk of mortality

Univariate Multivariate Multivariate Univariate P-value Odds Ratio P-value P-value

Demographics Ventricular Dysfunction Age > 75 years 0.14 2.4 0.10 Eject fraction > 40% 0.07 Black race 0.16 Hemodyn instability 0.00 I Diabetes 0.009 2.9 0.04 Renal failure I Previous MI 0.10 HR very high =50% 0.12 HR high 0.01 Perip Vasc Diasease 0.002 2.8 0.04 MPAP high 0.009 LVH by ECG 0.003 DPAP high 0.013 Calcified Asc Aorta 0.15

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Abbreviations: C O P D - chronic obstruct ive p u l m o n a r y disease; M I - myoca rd i a l infarction; R C A - f ight co rona ry ar tery; P D A - poster ior

descend ing co rona ry artery; E C G - e lec t rocard iographic ; L V H - left vent r icular hyper t rophy ; D P A P - diastolic p u l m o n a r y artery pressure;

CPB - c a r d i o p u l m o n a r y bypass; MPAP - m e a n p u l m o n a r y ar tery pressure; H R - hea r t rate; M A P - m e a n arterial pressure .

15. Thirty-five years with a computer

N. Ty Smith Professor Emeritus, Dept. Of Anesthesiology, University of California at San Diego, Veterans Administration Medical Center, 3350 La Jola Village Drive, San Diego, CA 92161 & Medical Director, Monitoring Division, Marquette Medical Systems, 8200 West Tower Avenue, Milwaukee, W153223, USA

The title should actually be: 'Thirty-five Years with Gifted People,' for I have been blessed with working with the best. This abstract lists some of those people and the innovations they developed. I apologize that it reads like the Vladivostok Telephone Directory, but it needed to fit the abstract limit. Most of the dates represent starting dates, and some may change by lecture time.

1962 1962 1963 1963 1963

1966 1970

1970 1971 1972 1973

1973 1973 1975

1976 1977 1978 1978 1980 1981 1982 1983 1984 1985 1985 1985 1985 1985 1986 1986

Stanford University - Worked with IBM 7090. Aldo Corbascio - Taught me about the ballistocardiograph (BCG), my introduction to bioengineering. Jay Weldon Bellville - Bought an analog computer, one of five in the world (Beckman EASE) Hiroshi Hara - Had designed the EASE and then taught us how to use it. Gerry Fleischi - Helped design an analog computer program for noninvasive stroke volume, etc., from the BCG Helmut Schwede - Helped design one of the early anesthetic control systems Jan Beneken, Aart Zwart, and Vince Rideout - Developed the first medical use of multiple transport modeling, on one of the other four Beckman EASE Computers. Fernando Lopes da Silva - Showed that dynamic halothane input and EEG output were linearly related. Ted Eger - Helped do BCG on Gigi, a young California gray whale. Karel Wesseling - Pulse-contour cardiac output. Yas Fukui - Hybrid (analog-digital) computer multiple-model transport modeling, with realistic cardiovascular and respiratory systems. Bob Fleming - DSA and median power frequency. Bob Fleming - Started the Biomedical Computer (BMC), possibly the first microcomputer in medicine. Bob Fleming, Yas Fukui, and John Coles - Nitroprusside controller, a digital and sampled-data controller. Same - Man vs. Machine, as controllers. Michail Demetrescu - Neurometrics EEG analyzer. Ira Rampil - Spectral-edge frequency. Alastair Roxborough - BMC-controlled ventilator. Andy Sarnat and Bob Fleming - Started voice recognition work. Karel Wesseling - Finapres. Mark Mitchell, Ed Meathe, et. al. - Started work on automated record keeping. Jeff Mandet, James Martin - Real-time digital model of CVS. Yas Fukui, Howard Schwid, Mike Quinn, and Charles Wakeland - Converted hybrid model to digital. Same - Developed Sleeper, an early anesthesia simulator. James Martin - Multiple-model adaptive control. Diatek - Lifescan EEG monitor. Mike Quinn - The use of simulation to decrease animal experiments. Warren Smith, Bob Dutton - The use of the EEG to predict movement during anesthesia. James Martin - Supervisory adaptive control. James Martin, Mike Quinn - Control systems used during cardiac surgery.

1987 1989 1992 1992 1994 1994

1994

1996

Diatek - ARKIVE. Tony Sebald, Michael Parti, Charles Gray - Sleeper on a PC. Ken Starko - BODY Simulation, a new concept in anesthesia simulation. Warren Smith, Bob Dutton - Prediction probability (PK). Warren Smith and Bob Dutton - A measure for assessing prediction accuracy. EMIT - ASA Committee on Electronic Media and Information Technology. Many incredible people to help the ASA into the electronic future. Retired - Joined Marquette Medical Systems. Working on electronic records, intelligent alarms, and all sorts of fun things. Working about 80 hours a week on computer-related projects.

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Conclusion: How lucky can a guy get? My main role has been that of a cheerleader.

16. An interactive hypermedia program to review pulmonary physiology and the effects of general anesthesia on normal pulmonary physiology and the patient with pulmonary co-existing disease

Jonathan P. Yim, George J. Sheplock & Simon C. Hillier Dept. of Anesthesia, Indiana University School of Medicine, Indianapolis, IN 46202, USA

This interactive hypermedia computer program is designed to educate anesthesia residents about important respira- tory physiology concepts and their consequences upon the everyday practice of anesthesia. This program reviews pulmonary physiology, mechanical ventilation, respiratory therapy and the anesthetic considerations for the patient with and without pulmonary co-existing disease. The program is divided into four main sections; pulmonary phys- iology, pulmonary pathophysiology, respiratory management, and clinical case studies. The program incorporates the use of interactive animations and graphics, digital video and audio, and hypermedia to review the important basic science and clinical concepts. An interactive case-based approach is used to reinforce the concepts presented in the basic science sections and to present important issues in perioperative respiratory management. There is also a key concept test designed to evaluate comprehension using a written question format.

The physiology section begins with a discussion on the functional residual capacity (FRC). The FRC is explored in depth to emphasize the paramount importance and relevance of the FRC to respiratory mechanics in the perioperative setting. Topics presented include: defining the FRC; factors determining the FRC; surfactant's role in increasing lung compliance; the effects of anesthesia on the FRC; the effects of a reduced FRC upon oxygen reserves during apnea and the speed of induction of inhalation anesthesia; the relation of the FRC to closing volume and its effects on gas exchange; the FRC's relationship to lung compliance and the work of breathing; and methods to restore the FRC towards normal.

Following the initial presentation on the FRC, other topics of respiratory physiology are covered which include: oxygen and carbon dioxide transport; pulmonary vascular resistance and blood flow distribution; the effects of hypoxic pulmonary vasoconstriction; control of ventilation; the importance of humidification; regional ventilation differences; ventilation-perfusion relationships; the effects of general anesthesia on upper airway patency, muscles of respiration, and lower airway resistance; the advantages and disadvantages of mask anesthesia; mechanisms of hypoxemia during anesthesia; mechanisms of hypercapnia and hypocapnia during anesthesia; and the physiologic effects of hypoxia, hyperoxia, hypercapnia, and hypocapnia.

The pathophysiology section presents pulmonary disease states and their effects on the respiratory system under anesthetic conditions. Topics reviewed include: obstructive lung disease; intrinsic and extrinsic restrictive lung disease; and pleural and mediastinal disorders. Respiratory management topics include: respiratory pharmacological agents; respiratory treatments and oxygen delivery systems; and mechanical ventilation.

After completing the core sections on pulmonary physiology, pathophysiology, and respiratory management, clinical case studies are presented to evaluate the user's comprehension of respiratory physiology concepts and the

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ability to apply them in clinical scenarios. The user may also test his understanding by completing a key concept test which utilizes a boards-type question format.