Crisis management during anaesthesia: the development of an anaesthetic crisis management manual.

BACKGROUND: All anaesthetists have to handle life threatening crises with little or no warning. However, some cognitive strategies and work practices that are appropriate for speed and efficiency under normal circumstances may become maladaptive in a crisis. It was judged in a previous study that the use of a structured "core" algorithm (based on the mnemonic COVER ABCD-A SWIFT CHECK) would diagnose and correct the problem in 60% of cases and provide a functional diagnosis in virtually all of the remaining 40%. It was recommended that specific sub-algorithms be developed for managing the problems underlying the remaining 40% of crises and assembled in an easy-to-use manual. Sub-algorithms were therefore developed for these problems so that they could be checked for applicability and validity against the first 4000 anaesthesia incidents reported to the Australian Incident Monitoring Study (AIMS). METHODS: The need for 24 specific sub-algorithms was identified. Teams of practising anaesthetists were assembled and sets of incidents relevant to each sub-algorithm were identified from the first 4000 reported to AIMS. Based largely on successful strategies identified in these reports, a set of 24 specific sub-algorithms was developed for trial against the 4000 AIMS reports and assembled into an easy-to-use manual. A process was developed for applying each component of the core algorithm COVER at one of four levels (scan-check-alert/ready-emergency) according to the degree of perceived urgency, and incorporated into the manual. The manual was disseminated at a World Congress and feedback was obtained. RESULTS: Each of the 24 specific crisis management sub-algorithms was tested against the relevant incidents among the first 4000 reported to AIMS and compared with the actual management by the anaesthetist at the time. It was judged that, if the core algorithm had been correctly applied, the appropriate sub-algorithm would have been resolved better and/or faster in one in eight of all incidents, and would have been unlikely to have caused harm to any patient. The descriptions of the validation of each of the 24 sub-algorithms constitute the remaining 24 papers in this set. Feedback from five meetings each attended by 60-100 anaesthetists was then collated and is included. CONCLUSION: The 24 sub-algorithms developed form the basis for developing a rational evidence-based approach to crisis management during anaesthesia. The COVER component has been found to be satisfactory in real life resuscitation situations and the sub-algorithms have been used successfully for several years. It would now be desirable for carefully designed simulator based studies, using naive trainees at the start of their training, to systematically examine the merits and demerits of various aspects of the sub-algorithms. It would seem prudent that these sub-algorithms be regarded, for the moment, as decision aids to support and back up clinicians' natural responses to a crisis when all is not progressing as expected.

Crisis management during anaesthesia: hypotension.

BACKGROUND: Hypotension is commonly encountered in association with anaesthesia and surgery. Uncorrected and sustained it puts the brain, heart, kidneys, and the fetus in pregnancy at risk of permanent or even fatal damage. Its recognition and correction is time critical, especially in patients with pre-existing disease that compromises organ perfusion. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for hypotension, in the management of hypotension when it occurs in association with anaesthesia. METHODS: Reports of hypotension during anaesthesia were extracted and studied from the first 4000 incidents reported to the Australian Incident Monitoring Study (AIMS). The potential performance of the COVER ABCD algorithm and the sub-algorithm for hypotension was compared with the actual management as reported by the anaesthetist involved. RESULTS: There were 438 reports that mentioned hypotension, cardiovascular collapse, or cardiac arrest. In 17% of reports more than one cause was attributed and 550 causative events were identified overall. The most common causes identified were drugs (26%), regional anaesthesia (14%), and hypovolaemia (9%). Concomitant changes were reported in heart rate or rhythm in 39% and oxygen saturation or ventilation in 21% of reports. Cardiac arrest was documented in 25% of reports. As hypotension was frequently associated with abnormalities of other vital signs, it could not always be adequately addressed by a single algorithm. The sub-algorithm for hypotension is adequate when hypotension occurs in association with sinus tachycardia. However, when it occurs in association with bradycardia, non-sinus tachycardia, desaturation or signs of anaphylaxis or other problems, the sub-algorithm for hypotension recommends cross referencing to other relevant sub-algorithms. It was considered that, correctly applied, the core algorithm COVER ABCD would have diagnosed 18% of cases and led to resolution in two thirds of these. It was further estimated that completion of this followed by the specific sub-algorithm for hypotension would have led to earlier recognition of the problem and/or better management in 6% of cases compared with actual management reported. CONCLUSION: Pattern recognition in most cases enables anaesthetists to determine the cause and manage hypotension. However, an algorithm based approach is likely to improve the management of a small proportion of atypical but potentially life threatening cases. While an algorithm based approach will facilitate crisis management, the frequency of co-existing abnormalities in other vital signs means that all cases of hypotension cannot be dealt with using a single algorithm. Diagnosis, in particular, may potentially be assisted by cross referencing to the specific sub-algorithms for these.

Crisis management during anaesthesia: myocardial ischaemia and infarction.

BACKGROUND: Myocardial ischaemia and infarction are significant perioperative complications which are associated with poor patient outcome. Anaesthetic practice should therefore focus, particularly in the at risk patient, on their prevention, their accurate detection, on the identification of precipitating factors, and on rapid effective management. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK" supplemented by a specific sub-algorithm for myocardial ischaemia and infarction in the management of myocardial ischaemia and/or infarction occurring in association with anaesthesia. METHODS: The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. RESULTS: Of the 125 incidents retrieved from the 4000 reports, 40 (1%) were considered to demonstrate myocardial infarction or ischaemia. The use of the structured approach described in this paper would have led to appropriate management in 90% of cases, with the remaining 10% requiring other sub-algorithms. It was considered that the application of this structured approach would have led to earlier recognition and/or better management of the problem in 45% of cases. CONCLUSION: Close and continuous monitoring of patients at risk of myocardial ischaemia during anaesthesia is necessary, using optimal ECG lead configurations, but sensitivity of this monitoring is not 100%. Coronary vasodilatation with glyceryl trinitrate (GTN) should not be withheld when indicated and the early use of beta blocking drugs should be considered even with normal blood pressures and heart rates.

Crisis management during anaesthesia: pneumothorax.

BACKGROUND: Pneumothorax is a potentially dangerous condition which may arise unexpectedly during anaesthesia. The diagnosis is one of exclusion, as initial changes in vital signs (cardiorespiratory decompensation and difficulty with ventilation) are non-specific, and other causes of such changes are more common, whereas local signs may be difficult to elicit, especially without full access to the chest. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for pneumothorax, in the management of pneumothorax occurring in association with anaesthesia. METHODS: Reports of pneumothorax were extracted and studied from the first 4000 incidents reported to the Australian Incident Monitoring Study (AIMS). The potential performance of the structured approach, using the combination of algorithims described above for each of the relevant incidents, was compared with the actual management as reported by the anaesthetists involved. RESULTS: Pneumothorax was noted as a possible diagnosis in 65 reports; 24 cases had a confirmed pneumothorax, of which 17 were in association with general anaesthesia. It was considered that, correctly applied, the application of the algorithms would have led to earlier recognition of the problem and/or better management in 12% of cases. CONCLUSION: Any pneumothorax may become a dangerous tension pneumothorax with the application of positive pressure ventilation. Limited access to the chest during anaesthesia may compromise the diagnosis. Recognition of any preoperative predisposition to a pneumothorax (for example, iatrogenic or traumatic penetrating procedures around the base of the neck) and close communication with the surgeon are important. Aspiration diagnosis in suspected cases and correct insertion of a chest drain are essential for the safe conduct of anaesthesia and surgery.

Crisis management during anaesthesia: obstruction of the natural airway.

BACKGROUND: Obstruction of the natural airway, while usually easily recognised and managed, may present simply as desaturation, have an unexpected cause, be very difficult to manage, and have serious consequences for the patient. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for obstruction of the natural airway, in the management of acute airway obstruction occurring in association with anaesthesia. METHODS: The potential performance for this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. RESULTS: There were 62 relevant incidents among the first 4000 reports to the AIMS. It was considered that the correct use of the structured approach would have led to earlier recognition of the problem and/or better management in 11% of cases. CONCLUSION: Airway management is a fundamental anaesthetic responsibility and skill. Airway obstruction demands a rapid and organised approach to its diagnosis and management and undue delay usually results in desaturation and a potential threat to life. An uncomplicated pre-learned sequence of airway rescue instructions is an essential part of every anaesthetist's clinical practice requirements.

Crisis management during anaesthesia: laryngospasm.

BACKGROUND: Laryngospasm is usually easily detected and managed, but may present atypically and/or be precipitated by factors which are not immediately recognised. If poorly managed, it has the potential to cause morbidity and mortality such as severe hypoxaemia, pulmonary aspiration, and post-obstructive pulmonary oedema. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD-A SWIFT CHECK", supplemented by a specific sub-algorithm for laryngospasm, in the management of laryngospasm occurring in association with anaesthesia. METHODS: The potential performance of this structured approach for the relevant incidents amongst the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. RESULTS: There were 189 reports of laryngospasm among the first 4000 incidents reported to AIMS. These were extracted and analysed. In 77% of cases laryngospasm was clinically obvious, but 14% presented as airway obstruction, 5% as regurgitation or vomiting, and 4% as desaturation. Most were precipitated by direct airway stimulation (airway manipulation, regurgitation, vomiting, or blood or secretions in the pharynx), but patient movement, surgical stimulus, irritant volatile agents, and failure to deliver the anaesthetic were also precipitating factors. Desaturation occurred in over 60% of cases, bradycardia in 6% (23% in patients aged <1 year), pulmonary oedema in 4%, and pulmonary aspiration in 3%. It was considered that, correctly applied, the combined core algorithm and sub-algorithm recommended for the diagnosis and management of laryngospasm would have led to earlier recognition of the problem and/or better management in 16% of cases. CONCLUSION: Laryngospasm may present atypically and, if not promptly managed effectively, may lead to morbidity and mortality. Although usually promptly recognised and appropriately managed, the use of a structured approach is recommended. If such an approach had been used in the 189 reported incidents, earlier recognition and/or better management may have occurred in 16% of cases.

Crisis management during anaesthesia: desaturation.

BACKGROUND: Desaturation occurs for many reasons under anaesthesia, some rare and obscure, and many potentially life threatening. The rapidity with which the cause is determined and appropriate management is instituted varies considerably between anaesthetists. OBJECTIVES: To examine the role of a previously described "core" algorithm COVER ABCD-A SWIFT CHECK, supplemented by a specific sub-algorithm for desaturation, in the management of incidents of desaturation occurring in association with anaesthesia. METHODS: The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. RESULTS: Amongst the first 4000 incidents reported to AIMS there were 584 episodes of desaturation in association with general anaesthesia; 41% were dealt with by COVER, 48% by ABCD, and 11% required a specific desaturation sub-algorithm. Nearly a fifth of all desaturations were caused by endobronchial intubation. Within the specific desaturation subgroup, half were due to pulmonary problems in the form of underlying lung disease, excessive secretions or obesity and a third could not be diagnosed. CONCLUSION: Desaturation may have many causes, some of which are obscure, and failure to respond promptly may place the patient at risk. In the face of persistent desaturation, management should consist of hand ventilation with 100% oxygen, completion of COVER ABCD-A SWIFT CHECK, and a return to a supine posture. Blood gases, chest radiography, and bronchoscopy may be required where desaturation is persistent and/or no apparent causes can be found.

A comparison of iatrogenic injury studies in Australia and the USA. I: Context, methods, casemix, population, patient and hospital characteristics.

OBJECTIVE: To better understand the differences between two iatrogenic injury studies of hospitalized patients in 1992 which used ostensibly similar methods and similar sample sizes, but had quite different findings. The Quality in Australian Health Care Study (QAHCS) reported that 16.6% of admissions were associated with adverse events (AE), whereas the Utah, Colorado Study (UTCOS) reported a rate of 2.9%. SETTING: Hospitalized patients in Australia and the USA. DESIGN: Investigators from both studies compared methods and characteristics and identified differences. QAHCS data were then analysed using UTCOS methods. MAIN OUTCOME MEASURES: Differences between the studies and the comparative AE rates when these had been accounted for. RESULTS: Both studies used a two-stage chart review process (screening nurse review followed by confirmatory physician review) to detect AEs; five important methodological differences were found: (i) QAHCS nurse reviewers referred records that documented any link to a previous admission, whereas UTCOS imposed age-related time constraints; (ii) QAHCS used a lower confidence threshold for defining medical causation; (iii) QAHCS used two physician reviewers, whereas UTCOS used one; (iv) QAHCS counted all AEs associated with an index admission whereas UTCOS counted only those determining the annual incidence; and (v) QAHCS included some types of events not included in UTCOS. When the QAHCS data were analysed using UTCOS methods, the comparative rates became 10.6% and 3.2%, respectively. CONCLUSIONS: Five methodological differences accounted for some of the discrepancy between the two studies. Two explanations for the remaining three-fold disparity are that quality of care was worse in Australia and that medical record content and/or reviewer behaviour was different.

A comparison of iatrogenic injury studies in Australia and the USA. II: Reviewer behaviour and quality of care.

OBJECTIVE: To better understand the remaining three-fold disparity between adverse event (AE) rates in the Quality in Australia Health Care Study (QAHCS) and the Utah-Colorado Study (UTCOS) after methodological differences had been accounted for. SETTING: Iatrogenic injury in hospitalized patients in Australia and America. DESIGN: Using a previously developed classification, all AEs were assigned to 98 exclusive descriptive categories and the relative rates compared between studies; they were also compared with respect to severity and death. MAIN OUTCOME MEASURES: The distribution of AEs amongst the descriptive and outcome categories. RESULTS: For 38 categories, representing 67% of UTCOS and 28% of QAHCS AEs, there were no statistically significant differences. For 33, representing 31% and 69% respectively, there was seven times more AEs in QAHCS than in UTCOS. Rates for major disability and death were very similar (1.7% and 0.3% of admissions for both studies) but the minor disability rate was six times greater in QAHCS (8.4% versus 1.3%). CONCLUSIONS: A similar 2% core of serious AEs was found in both studies, but for the remaining categories six to seven times more AEs were reported in QAHCS than in UTCOS. We hypothesize that this disparity is due to different thresholds for admission and discharge and to a greater degree of under-reporting of certain types of problems as AEs by UTCOS than QAHCS reviewers. The biases identified were consistent with, and appropriate for, the quite different aims of each study. No definitive difference in quality of care was identified by these analyses or a literature review.

Accidental bronchial intubation. An analysis of AIMS incident reports from 1988 to 1994 inclusive.

Accidental bronchial intubation was examined in the first 3947 cases reported to the Australian Incident Monitoring Study and was found to have accounted for 154 (3.7%) of the total incidents reported. Most incidents were detected in the operating theatre (93.5%) and during maintenance of anaesthesia (77.9%), by unexplained oxygen desaturation alone (63.6%). Capnography remained normal or unremarkable during 88.5% of the episodes. One-third of cases were associated with head or neck surgery and possible flexion of the patient's head. A RAE tube was used in 20% of incidents, a greater frequency than occurred in the study overall. A third party was implicated in 36 (23.4%) of cases. Ninety per cent of cases were considered preventable. Major morbidity occurred in three cases and unplanned intensive care admission was required in a further five. Almost two-thirds (61.1%) of the incidents might have been avoided by the proposed markings on the tracheal tube. We conclude that when arterial desaturation occurs at any stage during anaesthesia the possibility of bronchial intubation must be considered. Asymmetrical ventilation may be difficult to detect clinically and in most cases there is no change in capnography.

The Australian Incident Monitoring Study in Intensive Care: AIMS-ICU. The development and evaluation of an incident reporting system in intensive care.

Intensive care units are complex, dynamic patient management environments. Incidents and accidents can be caused by human error, by problems inherent in complex systems, or by a combination of these. Study objectives were to develop and evaluate an incident reporting system. A report form was designed eliciting a description of the incident, contextual information and contributing factors. Staff group sessions using open-ended questions, observations in the workplace and a review of earlier narratives were used to develop the report form. Three intensive care units participated in a two-month evaluation study. Feedback questionnaires were used to assess staff attitudes and understanding, project design and organization. These demonstrated a positive attitude and good understanding by more than 90% participants. Errors in communication, technique, problem recognition and charting were the predisposing factors most commonly chosen in the 128 incidents reported. It was concluded that incident monitoring may be a suitable technique for improving patient safety in intensive care.

The Australian Incident Monitoring Study. Errors, incidents and accidents in anaesthetic practice.

Human error is a pervasive and normal part of everyday life and is of interest to the anaesthetist because errors may lead to accidents. Definitions of, and the relationships between, errors, incidents and accidents are provided as the basis to this introduction to the psychology of human error in the context of the work of the anaesthetist. Examples are drawn from the Australian Incident Monitoring Study (AIMS). An argument is put forward for the use of contemporaneous incident reporting (eliciting relevant contextual information as well as details of use to cognitive psychologists), rather than the use of accident investigation after the event (with the inherent problems of scant information, altered perception and outcome bias). A classification of errors is provided. "Active" errors may be classified into knowledge-based, rule-based, skill-based and technical errors. Different strategies are required for the prevention of each type and it may now be useful to place more emphasis in anaesthetic practice on categories to which little attention has been directed in the past. "Latent" errors make an enormous contribution to problems in anaesthesia and several categories are discussed (e.g. environment, physiological state, equipment, work practices, personnel training, social and cultural factors). An approach is provided for the prevention and management of errors, incidents and accidents which allows clinical problems to be categorized, the relative importance of various contributing factors to be established, and appropriate preventative strategies to be devised and implemented on the basis of priorities determined from the AIMS data. Accidents cannot be abolished; however, an understanding of the factors underlying them can lead to the rational direction of resources and effort to prevent them and minimise their effects.

The Australian Incident Monitoring Study: an analysis of 2000 incident reports.

The Australian Patient Safety Foundation was formed in 1987; it was decided to set up and co-ordinate the Australian Incident Monitoring Study as a function of this Foundation; 90 hospitals and practices joined the study. Participating anaesthetists were invited to report, on an anonymous and voluntary basis, any unintended incident which reduced, or could have reduced, the safety margin for a patient. Any incident could be reported, not only those which were deemed "preventable" or were thought to involve human error. The Mark I AIMS form was developed which incorporated features and concepts from several other studies. All the incidents in this symposium were reported using this form, which contains general instructions to the reporter, key words and space for a narrative of the incident, structured sections for what happened (with subsections for circuitry incidents, circuitry involved, equipment involved, pharmacological incidents and airway incidents), why it happened (with subsections for factors contributing to the incident, factors minimising the incident and suggested corrective strategies), the type of anaesthesia and procedure, monitors in use, when and where the incident happened, the experience of the personnel involved, patient age and a classification of patient outcome. Enrollment, reporting and data-handling procedures are described. Data on patient outcome are presented; this is correlated with the stages at which the incident occurred and with the ASA status of the patients. The locations at which the incidents occurred and the types of procedures, the sets of incidents analysed in detail and a breakdown of the incidents due to drugs are also presented.(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. Which monitor? An analysis of 2000 incident reports.

The role of monitors in patients undergoing general anaesthesia was studied by analysing the first 2000 incidents reported to the Australian Incident Monitoring Study; 1256 (63%) were considered applicable to this study. In 52% of these a monitor detected the incident first; oximetry (27%) and capnography (24%) detected over half of the monitor detected incidents, the electrocardiograph 19%, blood pressure monitors 12%, a low pressure (circuit) alarm 8%, and the oxygen analyser 4%. Of the other monitors used, 5 first detected 1-2% of incidents, and the remaining 8 less than 0.5% each. The oximeter would have detected over 40% of the monitor detected incidents had its more informative modulated pulse tone always been relied upon instead of the "bleep" of the ECG. A theoretical analysis was then carried out to determine which of an array of 17 monitors would reliably have detected each incident had each monitor been used on its own and had the incident been allowed to evolve. To facilitate "scoring" of monitors, the incidents were categorized empirically into 60 clinical situations; 40% of applicable incidents were accounted for by only 5 clinical situations, 60% by 10 and nearly 80% by 20. 98% were accounted for by the 60 situations. A pulse oximeter, used on its own, would theoretically have detected 82% of applicable incidents (nearly 60% before any potential for organ damage). These figures for capnography are 55% and 43% and for oximetry and capnography combined are 88% and 65%, respectively. With the addition of blood pressure monitoring these become 93% and 65%, and of an oxygen analyser, 95 and 67%. Other monitors, including the ECG, each increase the yield by by less than 0.5%. The international monitoring recommendations and those of the Australian and New Zealand College of Anaesthetists are thoroughly vindicated by the patterns revealed in this study. The priority sequence of monitor acquisition for those with limited resources should be stethoscope, sphygmomanometer, oxygen analyser if nitrous oxide is to be used, pulse oximeter, capnograph, high pressure alarm, and, if patients are to be mechanically ventilated, a low pressure alarm (or spirometer with alarm); an ECG, a defibrillator, a spirometer and a thermometer should be available.

The Australian Incident Monitoring Study. The pulse oximeter: applications and limitations--an analysis of 2000 incident reports.

The first 2000 incidents reported to the Australian Incident Monitoring Study were analysed with respect to the role of the pulse oximeter. Of these 184 (9%) were first detected by a pulse oximeter and there were a further 177 (9%) in which desaturation was recorded. Of the 1256 incidents which occurred in association with general anaesthesia 48% were "human detected" and 52% "monitor detected". The pulse oximeter was ranked first and detected 27% of these monitor detected incidents; this figure would have been over 40% if an oximeter had always been used and its more informative modulated pulse tone relied upon instead of that of the "bleep" of the ECG. The pulse oximeter is the "front-line" monitor for endobronchial intubation, the fourth most common incident in association with general anaesthesia (it detected 87% of the 76 cases in which it was in use). It also played an invaluable role as a "back-up" monitor in 40 life-threatening situations in which "front-line" monitors (e.g. oxygen analyser, low pressure alarm, capnograph) were either not in use, were being used incorrectly or failed. Other situations detected, in order of frequency of detection, were: circuit disconnection, circuit leak, desaturation (severe shunt), oesophageal intubation, aspiration and/or regurgitation, pulmonary oedema, endotracheal tube obstruction, severe hypotension, failure of oxygen delivery, hypoxic gas mixture, hypoventilation, anaphylaxis, air embolism, bronchospasm, malignant hyperthermia, and tension pneumothorax.(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. The capnograph: applications and limitations--an analysis of 2000 incident reports.

The first 2000 incidents reported to the Australian Incident Monitoring Study were analysed with respect to the role of the capnograph. One hundred and fifty-seven (8%) were first detected by a capnograph and there were a further 18 (1%) in which capnography was contributory. Of the 1256 incidents which occurred in association with general anaesthesia 48% were "human detected" and 52% "monitor detected". The capnograph was ranked second and detected 24% of these monitor detected incidents; this figure would have been nearly 30% if a correctly checked, calibrated capnograph had always been used. The capnograph is a "front-line" monitor for oesophageal intubation, failure of ventilation, anaesthetic circuit faults, gas embolism, sudden circulatory collapse and malignant hyperthermia. It is a valuable "back-up" monitor when other monitors (e.g. low pressure alarm, pulse oximeter) are not in use, are being used incorrectly or fail. Such situations, in order of frequency of detection were: circuit-leak, overpressure of the breathing circuit, bronchospasm, leak of ventilator-driving-gas into the patient circuit, aspiration and/or regurgitation and hypoventilation. There were 20 reports of "failure", over two-thirds of which would not have occurred with appropriate checking and calibration. Seven were due to gas sampling problems and 6 to apnoea alarm failure. Two circuit leaks and 2 faulty unidirectional valves were not detected; on 3 occasions problems occurred due to power failure, calibration problems, or misinterpretation of an alarm.(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. The electrocardiograph: applications and limitations--an analysis of 2000 incident reports.

The first 2000 incidents reported to the Australian Incident Monitoring Study (AIMS) were analysed with respect to the role of the electrocardiograph (ECG). Of these, 138 (7%) were first detected by the ECG. Of the 1256 incidents which occurred in association with general anaesthesia (GA incidents) 48% were "human detected" and 52% "monitor detected", the ECG was ranked third and detected 121 (19%) of these monitor detected GA incidents. However over 98% of incidents first detected by the ECG were heart rate changes; they would also have been detected by a pulse meter or pulse oximeter which would have supplied additional information about the adequacy of peripheral perfusion. The ECG is a "first-line" monitor in situations with the potential for myocardial ischaemia, complex dysrhythmias or altered myocardial conduction and should be used in all critically ill patients as well as those at significant risk of these problems. The ECG frequently detects incidents involving minor physiological trespass, such as simple heart rate and rhythm changes associated with anaesthetic agents. These incidents are generally detected relatively early in their evolution. AIMS data has confirmed, however, that the ECG has such poor sensitivity for serious physiological changes such as hypoxia, hypercarbia and hypotension that it cannot even be regarded as a useful "back-up" monitor for these problems. Indeed a "normal" ECG in a dangerous situation may lead to a degree of complacency.(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. Blood pressure monitoring--applications and limitations: an analysis of 2000 incident reports.

Of the first 2000 incidents reported to the Australian Incident Monitoring Study, 1256 occurred in relation to general anaesthesia and 81 of the latter were first detected by blood pressure (BP) monitoring. A further 25 incidents not associated with general anaesthesia were first detected by blood pressure monitoring, giving a total of 106. In the monitor detection of incidents in relation to general anaesthesia, BP monitoring ranked fourth after oximetry, capnography and low pressure alarms. On the other hand, 38 incidents in which the problem was primarily one of significant change in BP were first detected by means other than the BP monitor (20 clinically, 12 by pulse oximetry and 6 by ECG). Early detection rates of hypotension were 60% for invasive methods, 40% for automated non-invasive (NIBP) devices and 30% for manual sphygmomanometry. There were 21 reports of BP monitor "failure"; the 11 of these which occurred with NIBPs involved unexplained false "low" or "high" readings and failure to detect profound hypotension, and led to considerable morbidity and at least one death. The 10 cases of invasive monitoring failure were predominantly due to mains power loss, hardware breakage or operator error. In a theoretical analysis of the 1256 GA incidents, it was considered that on its own, BP monitoring would have detected 919 (73%), but in the vast majority, by the time this detection has occurred, potential organ damage could not be excluded. It is recommended that BP be measured at regular intervals dictated by clinical requirements (usually at least every five minutes).(ABSTRACT TRUNCATED AT 250 WORDS)

The Australian Incident Monitoring Study. The oxygen analyser: applications and limitations--an analysis of 200 incident reports.

The first 2000 incidents reported to the Australian INcident Monitoring Study were analysed with respect to the role of the oxygen analyser; 27 (1%) were first detected by the oxygen analyser. All of these were amongst the 1256 incidents which occurred in association with general anaesthesia, of which 48% were "human detected" and 52% "monitor detected". The oxygen analyser was ranked 7th and detected 4% of these monitor detected incidents. This figure would have been much higher had the oxygen analyser been correctly used on more occasions. The oxygen analyser detected 10 ventilator-driving-gas leaks into the circuit, 6 hypoxic mixtures due to rotameter settings, 3 inappropriate nitrous oxide concentrations, 2 disconnections and 1 leak at the common gas outlet, and 2 partial and 1 total failure of ventilation. In a theoretical analysis of these 1256 incidents it was considered that the oxygen analyser, used on its own, would have detected 114 (9%), had they been allowed to evolve (3% before any potential for organ damage). In 4 incidents an oxygen analyser gave faulty readings, in 3 caused a leak and in one a total circuit obstruction; 5 incidents were not detected because the alarm had been disabled. Despite the advent of piped gas supplies, failure of gas delivery or delivery of a "wrong" gas mixture still occurs surprisingly frequently in current anaesthetic practice; hypoxic mixtures were supplied on 16 occasions, other "wrong" mixtures on 23 and the oxygen supply failed on 7 occasions.(ABSTRACT TRUNCATED AT 250 WORDS)