Development and practical use of a computerized anaesthesia protocol

6 Development and practical use of a computerized anaesthesia protocol P. M. O S S W A L D

Few technologies have achieved such a great influence in all parts of our life, within so short a time, as computerization has in the last 15 years. In science and administration, tasks can be performed in a fraction of the time they would take without computer technology. While in many parts of natural science computers quickly became indispensable, the use of computers in medicine developed comparatively slowly and with little initial success. After the first hesitant use of computer technology in medicine, especially in intensive care, the advance in development of integrated circuits led to an acceleration of their application. The rapid development of the computer market led to dramatic cost reductions; the capacity that could be purchased for one dollar increased in five years by a factor of 50 000. However, no changes occurred in the capacity to develop comparable software. Applications in anaesthesia and in intensive care concern monitoring as well as calculation and presentation of data on the screen (Olsson, 1980). However, in practice, the complexity of application and problems in patient care often cause difficulties, and the computer is put away or is insufficiently used. The aim of introducing computers is not to replace nurses by automating the supervision and therapy of patients, but to improve the surveillance of patients and to relieve physicians and nurses of difficult and time-consuming tasks. Computers in medicine have four main areas of use: processing administrative data, monitoring, training and decision-making.

Processing administrative data The use of computers for managing administrative data and calculating medical costs has become established in many areas of medicine. Annual anaesthesia statistics are particularly interesting for the administration of a large department of anaesthesiology. The use of a computer enables data to be compiled in a few minutes, which would formerly have taken several employees days or even weeks to produce. Processing of all anaesthetic administrative data is not only carried out more precisely by computer, but also more clearly. Experience has shown that this kind of annual documentation of the tasks of a department of anaesthesiology is beneficial for both the physicians and the administration (Pettersson et al, 1975). Bailli~re's Clinical Anaesthesiology--

Vol. 4, No. 1, June 1990 ISBN0-7020-1343-9

67 Copyright9 1990,byBailli~reTindall All rightsofreproductionin anyformreserved

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Computer-controlled monitoring Nowadays, it is almost second nature to see computers monitoring vital parameters and other medical equipment during anaesthesia and intensive care. In the past few years, various companies have brought out a new generation of monitoring equipment which incorporates the enormous recent developments in the hardware sector. Today there are numerous microprocessor-controlled monitoring systems and analytical devices available (Comerchero et al, 1979; Apple, 1980; Keininger, 1980; Klain and Firestone, 1980; Paulsen et al, 1980; Fournell et al, 1981; Lustig et al, 1981; Rader et al, 1981; Turney, 1981; Bender et al, 1983, Prakash et al, 1982). Even today, the use of computer technology in anaesthesiology and intensive care is limited essentially to statistical revision of simple data and balancing of fluid and nutritional requirements of patients undergoing intensive care. At this level, the computer technology employed encompasses database programs and spreadsheets or programs specifically written for the needs of the user. Ease of use and flexibility of these programs is not particularly great. The first areas of computer application dealt with recording vital parameters in intensive care wards. Norlander (1973) reported on a patient data system for surgery and intensive care. Conrad and George (1979) presented an off-line system supporting the management of patients under resuscitation. Kalinski reported on an interactive computer system making use of microprocessor technology for continuously recording haemodynamic parameters of patients. Peters et al (1979) developed special algorithms for improving cardiopulmonary management during weaning. Computers were then implemented for compiling reports and managing hospital records. First experiences were also gathered on closed-loop control of fluid and drug therapy. This was reported in two independent papers by Janic et al (1978). The development of computer technology has enabled us to define sensible areas of use and tasks for the clinical employment of such equipment, which include ECG displays, arrhythmia computers, automatic blood pressure monitors, respirators and anaesthetic inhalation agent analysers.

Training and decision support systems Computers have been used for several years now in medicine as a training tool. Well-structured programs support a high degree of training material that could not be offered in a comprehensible fashion by other methods. They are useful for responding to topical problems and in the preparation of seminars for students and colleagues during medical training. The use of small lap-top computers will be a decisive factor in the broader application of such systems (Gessner, 1979). The use of computers for immediate therapeutic decision-making during anaesthesia or intensive care is only implemented to a minimal extent at present and is indeed the most difficult problem to overcome. The problem

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is not just the non-availability of suitable computers or sufficiently wellthought-out, structured programs, but is rather more to do with the selection or availability of suitable monitoring devices. This has led to only cautious implementation of studies in this direction in the somewhat restricted areas of anaesthesiology and intensive care. In the area of intensive care medicine, the continuous monitoring and documentation of parameters has become routine practice, brought about partly by the industry and partly by the microprocessor systems developed by working groups. Predominantly, cardiovascular values are recorded on-line. For respiration, there is usually only the possibility of recording the frequency continually. Individual centres have developed programs for the on-line recording of other pulmonary parameters. It is important to consider the information coming from ICU, e.g. charting, planning and communications. On the whole, computer systems only are helpful in charting. In the area of anaesthesia, no suitable microprocessor system is offered commercially which meets the special requirements of this field for the measurement of cardiovascular and pulmonary variables. The making of an anaesthesia record is seen as an absolute requirement, and there is a large amount of data to be recorded. Information on the preoperative condition and the case history is essential for decisions on the intraoperative and postoperative course of the anaesthesia, and contributes decisively to the assessment of risk. Personal data of the patient must be included, especially details of serious previous and current illnesses, prescribed premedication, anaesthetic procedures, the operation to be performed and the names of the anaesthetists and surgeons. The intraoperative data recording must take into account a variety of off-line and on-line parameters, medication administered during anaesthesia and all vital parameters of respiration and circulation; complications and any other special features must be recorded and documented as they occur. Furthermore, fluid and volume balances must be made over the period of the anaesthesia. The available data have to be relevant, exact and clear. The data output must be helpful for medical decisions and must be easy to get. The presentation of data must be informative. In critical situations the reliability of the computer system is essential (Lake, 1990). Individual anaesthetic departments have tried to find an adequate solution, with the aim of replacing the handwritten anaesthesia record as far as possible. Systems have been conceived in Sweden and the USA which guarantee on-line monitoring of important anaesthetic values. The emphasis of these systems, however, is on recording and documenting data; a suitably transparent data recording, which would make the records irrelevant, is not offered. A further development can be seen in the USA in Atlanta, Georgia, unique so far in producing complete computer recording (Norlander, 1973; Salat, 1974; Bartels et al, 1979; Ehlers, 1979; Apple, 1980; Lutz and Kunze, 1980; Bender, 1981; Zeelenberg and Hoare, 1981). In recent years, numerous computer-controlled systems have been developed with the aim of improving the recording of haemodynamic and pulmonary data during anaesthesia (Whitesell et al, 1979; Luff and White, 1981), and at the same time partially automating the writing of anaesthetic

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reports (Nunn, 1969; Whitesell et al, 1979; Ribbe et al, 1980; Cushman and Bushman, 1983; Hartung et al, 1983; Naqvi, 1983; Prentice and Kenny, 1984). The Institute of Anaesthesiology and Intensive Care Medicine at the Mannheim Hospital had such a system in operation on a trial basis in 1980. The rapid development in the field of microcomputer technology towards less expensive systems with ever-increasing capacity, prompted a renewed look at this project to see if it could be further developed, taking into account all the experience gained up to date. Experience to date

The computer-controlled patient monitoring systems that we have been using for some years in our hospital at Mannheim now offer the possibility of collecting measurements from up to 8 on-line monitoring devices. This information is manually supplemented with off-line data. Experience has shown that immediate on-screen graphical representation of data is particularly helpful to the anaesthetist in assessing the course of anaesthesia. However, in this trial phase, weaknesses were demonstrated which would have to be eliminated when further developing such a system. The number of users, for example, remained limited to a small group of 'insiders' due to numerically coded instructions. It is clear that such systems wil| only become widely accepted for routine use if they are easy and simple to use, do not require any special data processing knowledge, and require no more effort than present recording methods. In the systems developed so far, it has always been a problem that they were designed as part of a network in which the data for the anaesthetic report were only stored temporarily in the microprocessor and then transmitted to the central minicomputer. Here, the data were condensed and stored in a compressed form for statistical evaluation at a later date. At the end of anaesthesia, the results of the anaesthetic report were printed on paper. This concept failed partly because of such basic difficulties as the very costly installation of data transmission lines from the sterile operating unit to the location of the central processor, a problem which will certainly have been encountered in many hospitals in a similar form. In addition, such a system makes very high demands upon the reliability of the central computer, because if it should fail for any reason, total system failure would result. Since the anaesthetic report is an important document (Opderbecke, 1981; Osswald et al, 1984) which is absolutely necessary at the end of anaesthesia for further treatment of the patient in the resuscitation room or ward, a possible delay in collection of data or partial loss of data is not acceptable under any circumstances. Having to keep conventional records also for 'safety reasons' means unacceptable extra work. COMPUTER ASSISTED ANAESTHESIA RECORD-SYSTEM (NAPROS) Hardware and software

The system we chose comprised an IBM microprocessor (XT/AT) with disk

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drive for storage of data and programs and an I B M Proprinter for printing out the anaesthetic report. All programs for the system are written in BASIC.

System description The system comprises a microcomputer, with disk drive and matrix printer, linked to a non-invasive arterial pressure monitor ( D i n a m a p 845a) and an inhalation anaesthetic monitor for automatic collection of the measured data (Figure 1). The built-in, four-channel analogue to digital converter automatically records cardiovascular data (systolic and diastolic blood pressure and heart rate) and the concentration of inhaled anaesthetic agent. Measurements are registered automatically (at 3-minute intervals), presented graphically onscreen and recorded. In addition, manually recorded values may be entered using the keyboard. Particular attention has been paid to ensuring that no data are lost in the event of a total system failure when these data and other usual parameters

Figure 1. The microcomputer layout with keyboard, monitor, disk drive and printer as a functional unit mounted on a trolley which also contains a Dinamap non-invasive pressure monitor and an Engstrom EMMA inhalation anaesthetic monitor (not visible here). From Osswald (1985).

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relating to infusions, drugs, administrative data, etc. are being stored. When using NAPROS, the course of anaesthesia up to any given point, and in particular the graphical representation of the cardiovascular data, can be reconstructed in a few moments at the touch of a button. NAPROS then prints out all collected data (measurements, drugs and infusions) in a short period of a few minutes via the matrix printer in the form of a preliminary anaesthetic report. The automatically collected data are printed out graphically at the relevant times. Data concerning the drugs administered and administration times are printed on the anaesthetic report at the time of input into the computer. This may produce a delay on the report if data are entered retrospectively, for example, if a drug administered at 8.00 a.m. was first entered at 9.00 a.m.

Functions of the anaesthetic report The following functions are built into the system: 1.

2. 3. 4.

Creation of the final anaesthetic report: Automatic recording of cardiovascular data and concentration of inhaled agent; entry of drugs; input and output of data from anaesthesia real-time printing of all automatically collected cardiovascular data and all drugs and laboratory values; creation of clear summaries; automatic calculation of balances; output in graphical or numerical form; possibility of recalling dose information for drugs; registration of administrative data. Automatic billing. Automatic costing of services rendered. Automatic calculation of materials used.

Selection of individual functions The user selects the desired functions from a menu: all functions currently available are displayed on-screen and can be selected by pressing the appropriate function key. Figure 2 shows a split-screen view in which cardiovascular data are presented graphically in the upper half of the screen and the basic menu is shown in the lower half.

Input of drugs and infusions The drugs or infusions used are entered by pressing the corresponding function key and adding the drug or infusion number. In addition, the administration time and the amount of drug or fluid administered must also be entered.

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Figure 2. T h e upper half of the screen displays the automatically recorded cardiovascular data and the lower half the m e n u of system functions available. F r o m Osswald (1985).

The computer automatically enters the current time for all drug or infusion entries, so that time needs only be corrected if the administration is entered retrospectively. A check routine follows the input of all data concerning drugs in order to verify whether values entered in the system are correct. If errors are determined, corrections can then be made. Data transfer to floppy disk takes place only after confirmation.

Recall of dose information for drugs NAPROS Offers the possibility of storing drug dose information as well as short summaries of drug information. A short tone is emitted upon input of a drug indicating that the system has stored the information. A selected circle of users can readily alter or update the pharmacological information using service programs.

Calculation of fluid balances An automatic calculation of the volume infused is carried out according to infusion type, for all infusions entered into the system. Similarly, data from the anaesthetist regarding loss of blood, urine excretion or other intraoperative fluid losses are balanced automatically. An intermediate balance can be recalled at any time in numerical or graphical form (Figure 3).

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Figure 3. The fluid balance is shown using a bar diagram. The input column is above the line and the output column below the line. F r o m Osswald (1985).

Providing that the time of preoperative fasting has been entered, the system calculates the theoretical loss of fluid using a basic requirements equation. However, confirmation of this figure is left to the anaesthetist, as the total clinical picture has to be taken into consideration for this calculation.

Overview of the drugs and infusions administered If the anaesthetist wishes to have an overview of the drugs or infusions administered so far, for example during long-term anaesthesia or after replacing a colleague, a list of these drugs or infusions and the amounts administered may be recalled from the system at any time. Either all the drugs administered or a specific drug can be called up as required. In the latter case, the sum of the individual amounts is determined and displayed.

Entering events and comments In addition to the parameters measured and the drugs administered, additional events may be entered using the method described above. Those events which occur most frequently are compiled as a menu so that they may be selected simply by pressing the appropriate key.

Entry of administrative and perioperative data Entry of administrative data such as name, date of birth, time of operation, duration of anaesthesia, etc., is the most time-consuming procedure, being carried out in a dialogue via the keyboard. Perioperative data such as the preoperative condition of the patient, the type of anaesthesia being used and complications may be entered at any suitable time before, during or after

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anaesthesia. Data entry may be interrupted at any time and continued at a later point if the course of anaesthesia requires the undivided attention of the anaesthetist.

Adaptation of the system to specific hospital situations The menu of drugs and infusions contained in the system was compiled paying particular attention to those drugs most frequently used in our hospital. At the same time, however, a procedure was devised that would allow simple adaptation to another hospital's requirements. This means that other drugs can be used or other numbers can be given to particular drugs or infusions without having to change the program. For these changes, an additional service program can be used which does not require specific data-processing knowledge. However, this service program is only available to a selected circle of users who are entitled to supplement or alter the main program. The same programming principle was applied to the potentially variable administrative and perioperative data, so that simple adaptation to local conditions is also possible in this area. DISCUSSION AND RESULTS NAPROS has now been in operation for about three years and 5000 anaesthetics have been documented with this system. In this time we have been able to show that it is possible to record the most important cardiovascular data reliably and in particular, objectively by automated documentation. Regarding system failures, NAPROS has proved to be so reliable after a short period in use that it has been possible to rely solely on the computer-produced anaesthetic report. As an additional conventional report is no longer necessary, the system has found favour with many of our anaesthetists and nurses and is assessed as being beneficial. However, a cost-benefit analysis is still difficult because we cannot be sure that the additional information provided by the system will be successfully used by the anaesthetist. We can only say that we have obtained better conditions and that the reliability has to be proved by a broader application. For that, more experience will be necessary. There have hardly been any problems as far as using the system is concerned, and a short introduction and a training period of a few hours have been sufficient for users to cope with the system. The number of physicians trained to use the system is now 17, and two to three hours are required for training. There were--and still are--negative attitudes, which are for the most part based on scepticism about the use of microcomputers in general. One of the reasons for this is the fact that computer systems, whatever the type, require the user to follow structured procedures and thus, to a certain extent, suppress spontaneous behaviour. In comparison with the usual method of compiling an anaesthetic report, the computer-controlled system undoubtedly produces a more objective report with regard to the parameters measured. Should a marked variation

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occur between manual values and the values that have been determined automatically, the automatic recording can be switched off, or manual values can be entered additionally into the system. Once the user has become accustomed to the different format (Figure 4), the automatically produced report is definitely more easily read than the often almost illegible handwriting found in some conventional reports. Initial time and motion studies have shown that the time necessary for completing the report is about 10% (6-17% for short anaesthesics, less for long-lasting anaesthesics) for both NAPROS and conventional methods. Thus the partial automation does not reduce documentation time. 1 n ~ - t L e i

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H o w e v e r , it should be r e m e m b e r e d that w h e n using N A P R O S , data are available i m m e d i a t e l y for statistical and scientific evaluation and also, for example, for cost calculations because of the system's data storage system. Part of the w o r k which w o u l d otherwise have to be carried out later for data recording is already carried out in the operating theatre. In short, although N A P R O S does not require m o r e time it offers m a n y additional possibilities. I m p r o v e m e n t of quality often is relative. T h e use of newer and faster hardware is of little value w h e n p r o b l e m s are caused by p r o g r a m failure or printer b r e a k d o w n . E v e n t o d a y , m a n y d e v e l o p m e n t s o f p r o g r a m systems are confined to specialized centres; it c a n n o t be expected that such systems can be transferred w i t h o u t p r o b l e m s to o t h e r hospitals with a different infrastructure. H o w e v e r , one can transfer the experiences with the c o m p u t e r s and with software. Applications of c o m p u t e r t e c h n o l o g y in anaesthesia and intensive care are still infrequent and it is very i m p o r t a n t that the experiences are published. H o w e v e r , c o m p u t e r t e c h n o l o g y has developed in the last years to be a useful and, we believe, essential part of patient m a n a g e m e n t in anaesthesia and intensive care. A c o m p u t e r system is only useful if it benefits the patient and poses few p r o b l e m s to the t e a m running it. REFERENCES

Apple HP (1980) Automatic noninvasive blood pressure monitors: what is available? In Gravenstein JS (ed.) EssentialNoninvasive Monitoring in Anesthesia. New York: Grune & Stratton. Bartels H, Adolf J, Bonke ST & Maurer PC (1979) Einsatz eines rechnergesttitzten Uberwachungs- und Dokumentationssystems in der postoperativen Behandlung von Risikopatienten. Intensivbehandlung 4: 99. Bender HJ (1981) Implementierung eines rechnergesti~tzten Patienteniiberwachungssystems. Mannheim: Diss. Bender HJ, Osswald PM, Hartung HJ & Lutz H (1983) Online-Erfassung hiimodynamischer und respiratorischer Gr6Ben in der Anaesthesie. Aniisthesiologica Intensivtherapie Notfallmedizin 18: 37-40. Comerchero H, Vernia M, Tivig G, Kalinsky D & Miller A (1979) Solo: an interactive microcomputer-based bedside monitor. Third Symposium on Computer Applications in Medical Care, Washington, USA. Conrad SA & George RB (1979) Computer assistance in assessment and management of mechanical ventilation. First Annual International Symposium on Computers in Critical Care and Pulmonary Medicine, Norwald, Connecticut, USA, 1979. Cushman J & Bushman JA (1983) The semiautomatic production of anaesthetic records. British Journal of Anaesthesia 55: 240. Ehlers CT (1979) Datenverarbeitung im Klinikum der Georg-August-Universit~it GOttingen. Beschreibung des Gesamtsystems G6ttingen. Fournell A, Schwarzhoff W, Steinhoff H & Falke K (1981) Technik der blutigen arteriellen und ven6sen Druckmessung auf einer Wach- und Intensivstation. In Epple E, Junger H, Blischer Wet al (eds) Rechnergestiitzte Intensivpflege. Stuttgart: Thieme. Gessner U (1979) Fehlerquellen bei der Berechnung von Lungen- und Herzfunktionsst6rungen. Biotechnische Umschau 3: 72. Hartung HJ, Bender HJ, Osswald PM, Lutz H & Olsson SG (1983) Entwicklung und Einsatz eines computergestiitzt erstellten Anaesthesieprotokolls. Anaesthesist 32: 205-213. Janic DS, Swarner DW, Henriksen KM & Wyman ML (1978) A computerized single entry system for recording and reporting data on high risk newborn infants. JournalofPediatrics 93: 519.

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Kieninger E (1980) Mikroprozessorsystem zur Erfassung und Darstellung von Vitalparametem mechanisch beatmeter Patienten. Diplomarbeit des Studiengangs Medizinische Informatik der Universitat Heidelberg, Fachhochschule Heilbronn. Klain MM & Finestone SC (1980) Computerized cardiopulmonary monitoring in the operating rooms. Second International Symposium on Computers in Critical Care and Pulmonary Medicine, Lund, Sweden. Lake CL (1990) Clinical Monitoring, pp 412-443. Philadelphia: WB Saunders. Luff NP & White DC (1981) Evaluation of the EMMA anaesthetic gas monitoring. British Journal of Anaesthesia 53: 1102. Lustig I J, Parrish JN, Augenstein JS, Civetta JM, Rodman GA & Caruthers TE (1981) Clinical experience with a minicomputer-based data management system in surgical intensive care. Third International Symposium on Computers in Critical Care and Pulmonary Medicine, Norwald, USA. Lutz H & Kunze I (1980) Autonome rechnergestiatzte Anaesthesiedokumentation. An~thesiologie Intensivtherapie Notfallmedizin 15: 494. Naqvi NH (1983) Computer-based automatic anaesthetic records. British JournalofAnaesthesia 55: 916. Norlander OP (1973) Patientendatensystem for Operation und Intensivpflege. Chirurg. 44: 446. Nunn JF (1969) Applied Respiratory Physiology with Special Reference to Anaesthesia. London: Butterworth. Olsson SC (1980) Clinical studies of gas exchange during ventilatory support--a method using the Siemens-Elema CO2 Analyser. British Journal of Anaesthesia 2: 491. Opderbeeke HW (1981) Der Verantwortungsbereich des Anaesthesisten. In Opderbecke HW, WeiBauer W (eds) Forensische Probleme in der Anaesthesiologie. Erlangen: Perimed. Osswald PM (1985) Computers in Critical Care and Pulmonary Medicine. Berlin, Heidelberg, New York, Tokyo: Springer-Verlag. Osswald PM, Hartung JH, Winter D, Bender HJ & Lutz H (1984) Das Narkoseprotokoll. Anaesthesist 33: 395-401. Paulsen AW, Frazier WT, Harbot RA & Hartney KJ (1980) Computer aided monitoring for the anesthetist. Second International Symposium on Computers in Critical Care and Pulmonary Medicine, Lund, Sweden. Peters RM, Brimm JE & Janson CM (1979) Clinical basis and use of an automated ICU testing system. First Annual International Symposium on Computers in Critical Care and Pulmonary Medicine, Norwald, Connecticut, USA. Pettersson SO, Seemann T, Wahlberg K, William-Olsson G, Ackerhammer E & (3berg PE (1975) The computer in the hospital service; a clinically oriented information system. Ostra Hospital, Gothenburg. Prakash O, Meij S, Zeelenberg C & van der Borden SG (1982) Computer-based patient monitoring. Critical Care Medicine 10:12. Prentice JW & Kenny GNC (1984) Microcomputer-based anaesthetic record system. British Journal of Anaesthesia 56: 1433. Rader C, Taylor W & Hansen D (1981) A distributed microprocessor respiratory intensive care monitoring system with mass spectrometer, proximal flowmeter and airway pressure transducer. Third International Symposium on Computers in Critical Care and Pulmonary Medicine, Norwald, USA. Ribbe T, HaUen B, Lumarsson D, Nygren G & Norlander O (1980) Data log system for monitoring during anaesthesia. Second International Symposium on Computers in Critical Care and Pulmonary Medicine, Lund, Sweden. Salat H (1974) Elektronische Patienteniiberwachung in der internistischen lntensivpflegestation des Kreiskrankenhauses Herford. ROntgenstrahlen 30: 437-442. Turney SZ (1981) Computerized multibed respiratory monitoring. Third International Symposium on Computers in Critical Care and Pulmonary Medicine, Norwald, USA. Whitesell R, Jablonski J & Burcas L (1979) Microprocessor automation of anesthesia records. Anesthesiology 51: 333. Zeelenberg C & Hoare MR (1981) Herzrhythmusiiberwachung. In Epple E, Junger H, Blischer W e t al (eds) Rechnergestatzte Intensivpflege. Stuttgart: Thieme.