Patterns of avoidable morbidity and mortality during anaesthesia

Mortality associated with anaesthesia, particularly in the developing world, is primarily related to two causes: airway problems and anaesthesia in the presence of hypovolaemia. A substantial proportion of anaesthesia-related deaths in the developed world occur in obstetric patients (15–17). Reports from Nigeria (18) and Malawi (19) demonstrate that these patients account for 50% of the anaesthesia-related deaths in developing countries. These studies also indicate that poor technique and lack of training, supervision and monitoring contribute to the high mortality. The potential for professionals to learn lessons about avoidable deaths is limited in many hospitals, as few such events are recorded or formally discussed.

These unacceptably high figures are indicative of a deteriorating situation. Information from Uganda in 2006 illustrates the constraints anaesthesia providers face, including shortages of the most basic facilities, equipment and medications and few physician anaesthetists (13 for 27 million people, compared with 12,000 for 64 million in the United Kingdom) (20); most anaesthesia is thus performed by non-physicians. This situation is similar to that in other parts of Africa (21–23). Although the situation varies widely throughout the world, anaesthesia services in many countries are extremely poor, particularly in rural areas (24,25). For the most part, deficiencies go unrecorded, as there are few systematic reviews of anaesthetic conditions and practice.

Perioperative mortality is usually due to a combination of factors related to patients (and their underlying medical condition), surgery, anaesthesia and management. In order to improve the safety of patients undergoing surgery, anaesthesia services must be made safer, especially in developing countries. This will require investment in the form of improved training of anaesthetists, safer facilities, functioning equipment, adequate drug supplies and mandatory pulse oximetry. International standards play an important role in guiding the development of anaesthesia services and should be adopted by ministries of health and local professional societies.

In order that no patient be harmed by anaesthesia, several goals must be met:

• Anaesthesia services should be made safer.
• Training and facilities for anaesthesia should be improved in many parts of the world.
• Safety in obstetric anaesthesia should be a priority, as obstetric patients are at particularly high risk from anaesthesia.
• Standardized global definitions of anaesthesia mortality should be developed.
• Every avoidable death is a tragedy, and lessons should be learnt from each instance of death during anaesthesia in order to reduce the risk of recurrence.

Approaches to improving the safety of anaesthesia

Anaesthesiology has played a pioneering role in the patient safety movement and in the establishment of standards for safe practice. Anaesthesiologists first codified the concept of ‘patient safety’ in 1984 at the inaugural meeting in Boston (United States) of the International Committee on Preventable Anesthesia Mortality and Morbidity. The first organization devoted to the concept of patient safety was the Anesthesia Patient Safety Foundation, created in the United States in 1985. This independent organization was the result of considerable effort on the part of the medical professionals involved, with the support of related industries and government regulators. The original ‘Harvard monitoring standards’ for intraoperative anaesthesia care were the first formally published, detailed medical standards of practice (26). They stimulated the American Society of Anesthesiologists to adopt their ‘Standards for Basic Intraoperative Monitoring’ in 1986. This initiative encouraged a cascade of standards, guidelines and protocols by professional anaesthesiology groups and societies around the world.

In 1989, the International Task Force on Anaesthesia Safety was established, comprising leaders in anaesthesia patient safety in nine countries (27). After two years of extensive work, the Task Force published the first International standards for a safe practice of anaesthesia (28). The document consisted of four printed pages and contained an outline of both general standards for the profession and practice of anaesthesiology and specific standards for peri-anaesthetic care and monitoring. Because of the variation in resources available in different locations around the world, the standards for equipment required for peri-anaesthetic care and monitoring were classified into three levels: basic, intermediate and optimal, to correlate realistically with available local resources. The essential care and monitoring concepts were universal and applicable everywhere, from the most isolated, resource-challenged locations in the developing world to the most economically and technologically advanced capitals. Ability to implement the concepts differed greatly, however. One focus was to help provide more anaesthetists in disadvantaged areas and to secure resources for improving anaesthesia quality and safety. The World Federation of Societies of Anesthesiologists formally adopted these international standards at its congress in The Hague in June 1992 and recommended them to all its member societies. The International standards for a safe practice of anaesthesia and 10 supporting documents were published as Supplement 7 to the European Journal of Anaesthesiology in January 1993 (28).

The work of the International Task Force underpins much of the current work in anaesthesia safety. At the most recent meeting of the World Federation of Societies of Anaesthesiologists, the 1992 standards were revised and updated and subsequently endorsed by the General Assembly during the 14th World Congress of Anaesthesiologists in Cape Town, South Africa, on 7 March, 2008 (29). The older standards had not, however, been actively promoted or endorsed globally. If the safety of anaesthetic services is to be improved, wide adoption of the standards is imperative. The main addition to the previous international standards is the requirement for pulse oximetry as an essential component of patient monitoring. Pulse oximetry is used almost universally in industrialized countries during the administration of anaesthesia. While strong, unequivocal evidence from a randomized clinical trial is lacking, few anaesthesia providers would willingly do without this device. As this represents a departure from the previous standards and imposes a potentially substantial cost on facilities, a full review of the evidence for this recommendation is warranted.

Evidence on monitoring with pulse oximetry and capnography

There is no evidence from randomized controlled trials that pulse oximetry or capnography has had an important effect on the outcome of anaesthesia (30). Evaluation of any safety intervention, however, requires consideration not only of the frequency of the adverse events that might be prevented but also of their potential severity. The prevention of an event may warrant considerable investment if it is serious, even if it is infrequent. Furthermore, prevention is more readily justified if the risks associated with the preventive measures are low. The death of, or brain damage to, an otherwise healthy person due to an entirely preventable anaesthetic mishap, such as ventilator disconnection or oesophageal intubation, is catastrophic; the risks associated with pulse oximetry and capnography are exceedingly low.

expert opinion: The anaesthesia community has led health care in the pursuit of patient safety (8). A prime example of systems improvement is the adoption of pulse oximetry and capnography as standard care in anaesthesia. In many countries today, there is a generation of anaesthetists who have never practised without pulse oximetry or capnography, and routine use of these techniques is mandated in the standards or guidelines of professional anaesthesia organizations in a number of countries (e.g. the Australian and New Zealand College of Anaesthetists, the Hong Kong College of Anaesthetists, the Malaysian Society of Anaesthesiologists, the Nigerian Society of Anaesthetists, the Association of Anaesthetists of Great Britain and Ireland, the American Society of Anesthesiologists in the United States and the Uruguay Society of Anaesthesiologists). It is likely that pulse oximetry and capnography are used in over 99% of general and regional anaesthetics in the United States and Canada, much of Europe, Australia, New Zealand and many other countries. This level of adoption reflects an almost universal conviction on the part of anaesthesia providers that these techniques contribute substantially to the safe provision of anaesthesia. The fact that the standards in many different countries are almost identical amounts to an extended ‘Delphi process’ for establishing consensus among experts. The weight of international expert opinion overwhelmingly supports use of these techniques for the safety of anaesthesia.

Compliance with best-practice guidelines for health care in general is sporadic and inconsistent, even in highly developed systems of health delivery (31); however, compliance with standards, guidelines and recommendations for the use of pulse oximetry and capnography in the developed world is virtually 100%. They have not only been mandated by authorities in the anaesthetic profession, they have also been embraced whole-heartedly and unequivocally by virtually every practising anaesthetist who has access to them (32). Informal surveys indicate that anaesthetists in many parts of the world cancel elective cases rather than proceed in the absence of either of these monitors. Widespread use of pulse oximetry is the primary goal of the Global Oximetry project, a collaboration among several professional societies of anaesthesiology and industry to promote widespread adoption of pulse oximetry, with particular emphasis in developing countries. The project includes evaluation of current oximeter design and cost, the educational requirements for effective use of pulse oximeters and barriers to their widespread adoption in appropriate settings (33). The adoption of pulse oximetry by anaesthetists has been an unusual, strikingly successful example of standardization of practice in health care.

controlled trials: A recent Cochrane review addressed the value of pulse oximetry in anaesthesia (30). The authors identified six studies of oximetry, two of which were deemed ineligible for inclusion because they lacked a control group or information on relevant postoperative outcomes. They concluded:

“The studies confirmed that pulse oximetry can detect hypoxaemia and related events. However, we have found no evidence that pulse oximetry affects the outcome of anaesthesia. The conflicting subjective and objective results of the studies, despite an intense, methodical collection of data from a relatively large population, indicate that the value of perioperative monitoring with pulse oximetry is questionable in relation to improved reliable outcomes, effectiveness and efficiency.”

The authors, however, went on to explain that, “Due to the variety of outcome variables used in the four studies, there are no two groups which could be compared directly by formal meta-analysis.”

Thus, the conclusions of this review were not based on a synthesis of a substantial body of comparable data but rather on the only large randomized controlled trial in which pulse oximetry has been evaluated, with some reference to three much smaller studies. This trial, conducted by Moller et al. (34), involved 20,802 patients and is impressive in concept, the detail of the data collected and the care with which the findings were presented. The study, however, lacked power to show differences in mortality associated with anaesthesia between groups. Given the observed rate of one death partially associated with anaesthesia per 335 patients, 1.9 million patients would have been needed to show a significant difference in outcome. Even for myocardial infarction, 500,000 patients would have been needed to show a difference in events, on the basis of the observed rate of 1 in 650 patients. Thus, the negative findings of the Moller study—revealing no change in overall rates of respiratory, cardiovascular or neurological complications—were related to outcomes that would have required much larger numbers of participants to be detected. It did, however, demonstrate a 19-fold increase in the detection of hypoxaemia in the group monitored by oximetry (p = 0.00001) as well as a significant increase in the detection of endobronchial intubation and hypoventilation. In addition, myocardial ischaemia occurred in half as many patients when oximetry was used.

The theoretical value of pulse oximetry lies in its ability to provide earlier, clearer warning of hypoxaemia than that provided by clinical signs alone. This may well reduce mortality rates and catastrophic hypoxic events, but these proved too infrequent to be evaluated in a study of only 20,000 patients. While anaesthesiologists still disagree about the implications of the Moller et al. study, it confirmed unequivocally that pulse oximetry facilitates early detection of hypoxaemia. Analysis of the data strongly suggested that oximetry improves outcomes as well. In addition, all the other identified studies demonstrated at least some benefit of the use of oximetry (Table II.2.1).

Table II.2.1

Other studies of pulse oximetry and its demonstrated benefits.

The results of trials of capnography are less clear, partly because its value is too obvious to require a randomized trial. Oesophageal intubation and hypoventilation are potentially disastrous if not identified early, and they can be detected reliably and promptly by the use of capnography (9,42). This is not the case with clinical signs alone. Capnography can also facilitate the detection of endobronchial intubation and airway circuit disconnections (43). No reasonable ethics board is likely to permit a randomized trial of capnography.

Incident reporting: In the seminal work of Cooper and his group, reporting of incidents identified failure to deliver oxygen to patients as the leading cause of mortality during anaesthesia (44). Over a decade ago, qualitative analysis of 2000 incidents showed a reduction in cardiac arrest when pulse oximetry was used, 9% of which were first detected by pulse oximetery (45). A theoretical analysis of the subset of 1256 incidents involving general anaesthesia showed that pulse oximetry on its own would have detected 82% of them. Of these, 60% would have been detected before any potential for organ damage occurred. Capnography alone would have detected 55% of these 1256 incidents. If both oximetry and capnography had been used in combination, 88% of the adverse events would have been detected, 65% before potential permanent damage (46). A recent review of 4000 incidents and over 1200 medico-legal notifications reported by anaesthetists in Australia and New Zealand revealed no cases of hypoxic brain damage or death due to inadequate ventilation or misplaced tubes since the introduction of oximetry and capnography (10).

Inferences from data on anaesthesia mortality: An analysis of the effects of oximetry and capnography over time in the Closed Claim Project² of the American Society of Anesthesiologists showed that although the number of damaging events due to respiratory failure decreased, the number of cardiovascular damaging effects increased (47). A separate analysis based on changes in the patterns of incident reporting indicated, however, that catastrophic hypoxic events are much less common today than they were before the introduction of these monitors (10). Anaesthesia is safer today than it was before these techniques were introduced, particularly in the developed world, where oximetry and capnography are used with nearly 100% compliance.

Other considerations on oximetry and capnography: A key element of pulse oximetry and capnography is their safety. While either type of monitor could provide misleading information because of technical problems, this is uncommon. In the study by Moller et al., for example, it occurred in 2% of cases. Experience and training allow most problems of this type to be identified and corrected.

Use of these devices requires an understanding of the relevant physiology and pathological processes leading to the changes they indicate. Their limitations and the possibility of incorrect or artefactual readings must also be appreciated. For example, in the United Kingdom, many doctors and nurses are inadequately prepared to interpret oximetry readings accurately (48). Users must also know how to respond effectively if oxygen saturation falls, by, for example, administering supplemental oxygen. Any clinician trained to give anaesthetics safely, including those not medically licensed, should, however, be able to incorporate either or both techniques into their practice within a short time.

While the cost of pulse oximetry has fallen dramatically over the past 20 years, concern about capital outlay and resource constraints is germane. Oximeters are relatively inexpensive (e.g. less than US$1000) and may be much cheaper in many places, such as China, where they are available at a fraction of this price. When calculated over the life of the machine and the number of patients on whom it can be used, this simple monitoring device becomes exceedingly cost–effective. In addition, harm due to anaesthetic mishaps is not cost-free, and a single error averted with pulse oximetry justifies its initial cost. The devices themselves have excellent visual and auditory outputs, are reliable and robust and do not require much maintenance. The probes are, however, readily damaged and their replacement represents a relatively high proportion of the overall cost of oximetry. It is not easy to calculate the cost per patient of use of pulse oximetry, but the cost of probes over time is likely to equal or exceed that of the actual device. Reliable, resistant probes are needed. The cost of capnography is somewhat higher, and maintenance is a little more challenging than for oximetry.

Conclusion: Mandated use of pulse oximetry and capnography in the developed world has stood the test of time. In settings with limited resources, the issue is somewhat less clear because of arguments about priorities for health-care funds. The overwhelming weight of evidence is that these techniques together improve safety, but it seems likely that much of the gain can be obtained from oximetry alone. Oximetry appears to provide early warning in a greater variety of situations than capnography (46). It will alert clinicians to problems in every situation that would be detected by capnography, perhaps later but certainly in time for action to be taken. Conversely, there are many situations in which oximetry is potentially life-saving and in which capnography alone might not be as helpful. Finally, oximetry is less expensive and less difficult to maintain than capnography.

Preparation for and delivery of anaesthesia

The provision of safe anaesthesia depends on careful preparation, which is facilitated by a systematic approach to reviewing the patient, machine, equipment and medications. This is ideally based on a formal check of the anaesthesia system. In addition to the personnel involved in delivering anaesthetic, the anaesthesia system includes:

• any machine or apparatus that supplies gases, vapours, local anaesthesia or intravenous anaesthetic agents to induce and maintain anaesthesia;
• any equipment necessary for securing the airway;
• any monitoring devices necessary for maintaining continuous evaluation of the patient; and
• the patient himself or herself, correctly identified, consensual and evaluated preoperatively.

In preparing for anaesthesia, the anaesthesia system should be checked before each anaesthetic, before the start of each operating day and after any repairs or maintenance to equipment or the introduction of new equipment. Figure 2.1 shows a universally applicable list of the checks to be made before anaesthetizing any patient. If the items on this list are available and functioning correctly before every anaesthetic, many mishaps can be prevented and lives will be saved. Additional checks to be undertaken before the first case of the day will depend on the level of resources available and should be decided locally.

Figure 2.1

Proposed list of anaesthesia safety checks before any anaesthetic.

Anaesthesia is usually administered in the operating room but may be required in intensive care units, emergency departments or other locations, such as radiology suites. There are clear requirements for the provision of safe anaesthesia services and recommended approaches for purchasing equipment. Even if there are financial constraints, it is the responsibility of the hospital management to maintain operating rooms and equipment and to provide an appropriate supply of medications and other consumables.

Facilities: The operating room should be of an appropriate size, well lit, conform to relevant electrical safety codes and meet design requirements that minimize hazards from fire, explosion and electrocution. Electricity and fresh water should always be supplied, and a back-up electrical generator should be immediately available.

A maintenance programme must be established in each hospital. All anaesthetic and ancillary equipment should be inspected regularly by qualified personnel and a maintenance record kept. Ideally, routine maintenance should not interrupt clinical services.

Secure storage is required for medications, particularly opioid drugs, and anaesthetic equipment. A refrigerator is required for storing drugs such as suxamethonium. Infection control measures are required to ensure that potentially infectious materials or agents are not transferred between patients or personnel. These should include respiratory equipment (e.g. disposable filters to protect patients and circuits), syringes, infusion pump administration sets and multi-dose drug vials. Sterile practice must be followed for clinical procedures such as spinal anaesthesia or insertion of central venous lines.

Wherever obstetric anaesthesia is performed, a separate area for assessment and resuscitation of newborns, including designated oxygen, suction apparatus, electrical outlets, a source of radiant heat and equipment for neonatal airway management and resuscitation, should be provided.

Policies about the running of operating rooms should be agreed. These should include details on the composition and organization of operating schedules. A recordkeeping system (paper or electronic) for anaesthesia and surgery is essential.

Anaesthesia equipment: An anaesthesia delivery system or machine is a vital part of the system but cannot function safely on its own. A professionally trained anaesthesia provider and patient monitoring devices are also mandatory for the delivery of safe care. Anaesthesia equipment should be suitable for the full range of patients treated at the facility. In addition, it should function effectively in the local environment.

Anaesthesia can be given intravenously, using agents such as ketamine, or as inhaled mixtures of volatile gases, such as halothane or isoflurane. Anaesthesia gases can be delivered through continuous flow equipment (e.g. a Boyles machine), which depends on supplies of compressed gases, or by drawover equipment (e.g. an Epstein Macintosh Oxford [EMO] system), which uses ambient air with added oxygen. In both systems, a vaporizer is needed to deliver an accurate concentration of the volatile agent.

In hospitals with unreliable compressed gas supplies, continuous-flow anaesthesia machines cannot function safely; in this situation, drawover equipment or machines based on oxygen concentrators have considerable advantages. When anaesthesia machines are purchased, the local environment must be taken into account to ensure that the machine will function correctly and can be maintained or repaired.

Gas Supplies in anaesthesia: Oxygen is essential for almost all anaesthesia and must be readily available during induction, maintenance and recovery. Many patients require additional oxygen postoperatively as well. Oxygen may be supplied to operating rooms in cylinders or via pipelines from a central oxygen distribution point. Hospital oxygen systems may be based on liquid oxygen plants, large cylinders in central banks or oxygen concentrators. Whichever system is used, there must be a method for confirming that the oxygen supplies are adequate before starting anaesthesia. There should always be a back-up source of oxygen, such as a reserve cylinder.

Medical gas pipeline systems, connectors, pressure regulators and terminal units should meet national standards for identification, construction and installation. All safety regulations for the preparation, storage, identification and use of medical gases, anaesthetic drugs and related materials must be met. Wherever anaesthetic gases are used, scavenging systems within the airway circuit should be in place to reduce the risk for long-term exposure.

When oxygen concentrators are installed, users must be aware that the fraction of inspired oxygen (FiO2) delivered can vary between 0.93 and 0.99. Concentrators differ in size: some are capable of supplying an entire hospital, while others are designed to be used as the oxygen source for a single machine.

Air is commonly used during anaesthesia. Medical air is normally supplied by pipeline from a central compressed supply and is often used for a number of other purposes in operating rooms (e.g. for power tools and tourniquets) in addition to anaesthesia. Ambient air is used in draw-over anaesthesia.

Nitrous oxide is an analgesic gas often used in anaesthesia. It is supplied as a liquid in high-pressure cylinders and vaporizes to form the gas breathed during anaesthesia. Nitrous oxide is always used with oxygen. Anaesthesia machines should be designed so that it is impossible to administer a hypoxic mixture of nitrous oxide. In many countries, nitrous oxide is expensive. It is not often used in modern anaesthesia and is not classified as an essential gas. In situations of limited resources, it is safer to dispose with nitrous oxide altogether.

Monitoring: Equipment for monitoring may be integrated within the anaesthesia machine or be provided as separate modules. One monitor can display a number of parameters or have a single function. Monitors are complex, with delicate electronic components that are sensitive to heat, dust, vibration, sudden movement and rough handling.

The most important component of monitoring is the continuous presence of a trained anaesthetist, whose expertise is augmented by the physiological information displayed on the monitoring devices. In addition to monitoring, careful continuous clinical observation is required, because the equipment may not detect clinical deterioration as rapidly as a skilled professional.

Supplemental oxygen is also essential for all patients undergoing general anaesthesia, and the anaesthetist should verify the integrity of that supply. Ideally, the inspired oxygen concentration is monitored throughout anaesthesia with an instrument fitted with an alarm set off by a low oxygen concentration. This ensures that the patient is protected against oxygen supply failure or the delivery of a hypoxic gas mixture. Integrated and fail-safe systems, for example tank yokes and hose connections, should be used to prevent misconnection of gas sources. As an added measure, tissue oxygenation should also be monitored continuously by a quantitative monitor of blood oxygenation (e.g. pulse oximetry). This provides a secondary system to ensure that the patient does not become hypoxic during surgery. A redundant system such as this is essential, as the consequence of hypoxia can be catastrophic. Hypoxia is highly preventable with careful planning and monitoring. Adequate illumination and exposure of the patient can also provide visual clues to hypoxia by allowing observation of the lips or nail beds.

As the adequacy of the airway, breathing and circulation is essential for safe delivery of anaesthesia, continuous monitoring is extremely important. For the first two, this can be accomplished by observation and auscultation at the very least, or by using a precordial, pretracheal or oesophageal stethoscope. When a breathing circuit is used, the reservoir bag can also be observed. The correct placement of an endotracheal tube can be confirmed, as can the adequacy of ventilation, by displaying the expired carbon dioxide waveform and concentration by capnography. When mechanical ventilation is used, disconnect alarms are essential to prevent catastrophic disconnection of the patient from the ventilator. Circulation is easily monitored by palpation, auscultation, a display of the pulse waveform or electrocardiograph trace. Pulse oximetry has the added benefit of continuous monitoring of both tissue perfusion and heart rate. Arterial blood pressure provides a measure of the adequacy of the peripheral circulation. It can be measured simply with a blood pressure cuff at appropriate intervals (usually at least every 5 minutes, and more frequently if indicated by clinical circumstances). Continuous measurement and display of arterial pressure using invasive monitoring may also be necessary in certain circumstances.

Homeostatic mechanisms for maintaining body temperature are frequently undermined during anaesthesia. Hypothermia can increase the risk for infection and cause problems of hypocoagulation. Hyperthermia can be one of the first signs of a medication or anaesthetic reaction. A means of measuring body temperature is an important component of patient monitoring and should be used at frequent intervals where clinically indicated, such as in a prolonged operation or in young children.

Finally, the depth of anaesthesia must be assessed regularly throughout the operation to ensure appropriate levels of pain control and sedation. This includes an assessment of the state of paralysis when neuromuscular blocking agents are used.

Ancillary equipment and medications: In addition to anaesthesia apparatus, ancillary equipment and medications are required to manage emergencies such as trauma, eclampsia, cardiac arrest and malignant hyperthermia. Patient warming devices, intravenous fluid warmers and special padding to support patients during surgery improve the quality of care. A self-inflating breathing bag is necessary in case of gas flow failure. Units for the care of children should have special paediatric equipment, including X-ray and ultrasound facilities.

Hospitals should ensure that adequate supplies of anaesthetic drugs are maintained. Table II.2.2 provides guidance for such materials and equipment, but each national society should have guidelines relevant to their environment. Drugs should be correctly stored, labelled in the local language and used before their expiration date. Safe methods of drug administration should be practised by all staff (see Objective 5).

Table II.2.2

Guide to infrastructure, supplies and anaesthesia standards at three levels of health-care facilities.

Infrastructure, supplies and care standards: WHO has established a list of necessary equipment for resuscitation, acute care and emergency surgery and anaesthesia in countries with limited health budgets. This is updated in Table II.2.2. The three-level model takes into account the fact that the provision of staff and equipment to meet the needs of the population served by the type of hospital considered must be within the constraints of available resources and that not all facilities can provide every service.

In the smallest units, many basic surgical procedures are undertaken with local anaesthesia. Emergency operations (notably caesarean sections and other obstetric procedures) are often performed under ketamine or regional anaesthesia without access to proper facilities or anaesthetic equipment. At times, anaesthesia is provided under the supervision of the surgeon as the most highly qualified health professional available. Despite the fundamental issue of resources, all health units should strive to meet the ‘highly recommended’ WHO standards listed below. They should also work to meet as many of the ‘recommended’ standards as possible.

In considering the formulation of standards and the requirement to balance resources against requirements, health authorities and administrators should align the standards of ‘highly recommended’, ‘recommended’ and ‘suggested’ with the three levels of facilities outlined in Table II.2.2. For each level of facility, it is desirable to exceed the applicable anaesthesia standard. In well-resourced locations with well-functioning facilities, professionals should be able to exceed the ‘recommended’ anaesthesia standard.

Recommendations

Highly Recommended

• The first and most important component of peri-anaesthetic care is the continuous presence of a vigilant, professionally trained anaesthesia provider. If an emergency requires the brief temporary absence of the primary anaesthetist, judgement must be exercised in comparing the threat of an emergency to the risk of the anaesthetized patient's condition and in selecting the clinician left responsible for anaesthesia during the temporary absence.
• Supplemental oxygen should be supplied for all patients undergoing general anaesthesia. Tissue oxygenation and perfusion should be monitored continuously using a pulse oximeter with a variable-pitch pulse tone loud enough to be heard throughout the operating room.
• The adequacy of the airways and of ventilation should be monitored continuously by observation and auscultation. Whenever mechanical ventilation is employed, a disconnect alarm should be used.
• Circulation should be monitored continuously by auscultation or palpation of the heart beat or by a display of the heart rate on a cardiac monitor or pulse oximeter.
• Arterial blood pressure should be determined at least every 5 minutes and more frequently if indicated by clinical circumstances.
• A means of measuring body temperature should be available and used at frequent intervals where clinically indicated (e.g. prolonged or complex anaesthesia, children).
• The depth of anaesthesia (degree of unconsciousness) should be assessed regularly by clinical observation.

Recommended

• Inspired oxygen concentration should be monitored throughout anaesthesia with an instrument fitted with a low-oxygen concentration alarm. In addition, a device to protect against the delivery of a hypoxic gas mixture and an oxygen supply failure alarm should be used.
• Continuous measurement and display of the expired carbon dioxide waveform and concentration (capnography) should be used to confirm the correct placement of an endotracheal tube and also the adequacy of ventilation.
• The concentrations of volatile agents should be measured continuously, as should inspiratory or expired gas volumes.
• An electrocardiograph should be used to monitor heart rate and rhythm.
• A cardiac defibrillator should be available.
• Body temperature should be measured continuously in patients in whom a change is anticipated, intended or suspected. This can be done by continuous electronic temperature measurement, if available.
• A peripheral nerve stimulator should be used to assess the state of paralysis when neuromuscular blocking drugs are given.

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Footnotes

2

The American Society of Anesthesiologists Closed Claims Project is an in-depth investigation of closed anesthesia malpractice claims designed to identify major areas of loss, patterns of injury, and strategies for prevention (http://depts​.washington​.edu/asaccp/ASA/index.shtml accessed 3 June 2008).