Indian Journal of Anaesthesia

: 2009  |  Volume : 53  |  Issue : 4  |  Page : 425--433

Critical Incident Reporting in Anaesthesia: A Prospective Internal Audit

Sunanda Gupta1, Udita Naithani2, Saroj Kumar Brajesh3, Vikrant Singh Pathania4, Apoorva Gupta5,  
1 Professor, Department of Anaesthesia and Critical Care, RNT Medical College, Udaipur 313001, Rajasthan, India
2 Assistant Professor, Department of Anaesthesia and Critical Care, RNT Medical College, Udaipur 313001,Rajasthan, India
3 Medical Officer, Department of Anaesthesia and Critical Care, RNT Medical College, Udaipur 313001, Rajasthan, India
4 PG Student, Department of Anaesthesia and Critical Care, RNT Medical College, Udaipur 313001, Rajasthan, India
5 Sr.Resident, GBH American Hospital, Udaipur 313001, Rajasthan, India

Correspondence Address:
Sunanda Gupta
26, Navratna Complex, Near Bedla Road, Udaipur, Rajasthan


Critical incident monitoring is useful in detecting new problems, identifying `near misses«SQ» and analyzing factors or events leading to mishaps, which can be instructive for trainees. This study was aimed at investigating potential risk factors and analyze events leading to pen-operative critical incidents in order to develop a critical incident reporting system. W conducted a one year prospective analysis of voluntarily reported 24- hour-perioperative critical inci­dents, occurring in patients subjected to anaesthesia. During a one year period from December 2006 to December 2007, 14,134 anaesthetics were administered and 112(0.79%) critical incidents were reported with complete recov­ery in 71.42%(n=80) and mortality in 28.57% (n=32) cases. Incidents occurred maximally in 0-10 years age (23.21%), ASA 1(61.61%), in general surgery patients (43.75%), undergoing emergency surgery (52.46%) and during day time (75.89%). Incidence was more in the operating theatre (77.68%), during maintenance (32.04%) and post-operative phase (25.89%) and in patients who received general anaesthesia (75.89%). Critical incidents occurred clue to fac­tors related to anaesthesia (42.85%), patient (37.50%) and surgery (16.96°lo). Among anaesthesia related critical incidents (42.85% n=48/112), respiratory events were maximum (66.66%) mainly at induction (37.5%) and emer­gence (43.75%), and factors responsible were human error (85.41%), pharmacological factors (10.41%) and equip­ment error (4.17%). Incidence of mortality was 22.6 per10, 000 anaesthetics (32/14,314), mostly attributable to risk factors in patient (59.38%) as compared to anaesthesia (25%) and surgery (9.38%). There were 8 anaesthesia related deaths (5.6 per 10, 000 anaesthetics) where human error (75%) attributed to lack of judgment (67.50%) was an important causative factor. We conclude that critical incident reporting system may be a valuable part of quality assurance to develop policies to prevent recurrence and enhance patient safety measures.

How to cite this article:
Gupta S, Naithani U, Brajesh SK, Pathania VS, Gupta A. Critical Incident Reporting in Anaesthesia: A Prospective Internal Audit.Indian J Anaesth 2009;53:425-433

How to cite this URL:
Gupta S, Naithani U, Brajesh SK, Pathania VS, Gupta A. Critical Incident Reporting in Anaesthesia: A Prospective Internal Audit. Indian J Anaesth [serial online] 2009 [cited 2020 Dec 5 ];53:425-433
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In recent years anaesthesia, in spite of low mor­tality, is still associated with significant morbidity. There appears to be considerable conformity that anaesthe­sia risk is an important public health concern and that it is reducible [1] . Further, there is reason to believe that a substantive portion of that risk is related to human er­ror resulting from errors in management or deviation from accepted practice [2] . If the frequency of error has to be decreased, a clearer understanding of that pro­cess is needed, the circumstances that encourage error should b e identified and the relative frequencies of dif­ferent classes of errors should be established.

Since its early adoption in the field of aviation [3] and later in the field of anaesthesia [4],[5] ; the collection o' dataon critical incidents is gaining acceptance in ana esthesia. Howeverthere are still sporadic studies [6],[7],[8] fron the developing countries which have tried to analyze and evaluate the frequency of critical incidents "related' to anaesthetic procedures.

Ouraim was to identifythe incidence, outcome anc potential riskfactors leadingto critical incidents durinf anaesthesia in a generaltertiaty care teaching hospital catering to mostly tribal patients and to promote volun tart' reporting of critical incidents in our department.


After obtaining approval from the hospital ethics committee, a one year prospective analysis of perioperative critical incidents was conducted in ater­tiary care teaching hospital situated matribalbelt from December 2006 to December 2007. Since it was an observational study without any intervention, consent from patient was not required.

In afaculty meeting of the department, it was de­cidedto implement 'critical incident reporting' asa quality assurance measure and anaesthesiologists were asked to report 24-hour-perioperative critical incidents, oc­curring in patients subjected to anaesthesia. A critical eventwas defined as "An event underanaesthesia care which had the potential to lead to substantial negative outcome (ranging from increased length ofhospital stay to death or permanent disability or cancelled operative procedure) if leftto progress"[4],[9]

Indigenous "Critical Incident Reporting Form" was developed and were made available in all the opera­tion theatres, post operative wards and Intensive Care Units orHigh Dependency Units. Anaesthesiologists were regularly motivated and reminded to report criti­cal incidents on an anonymous and voluntary basis and care was takento maintain complete confidentiality. In these forms, detailed contextual information duringre­cording of an event which would enhance the subse­quent review of the incident was also included.

The critical incident reporting form had two parts:

1. Description part: It was filled by anaesthesiologists who were conducting the case. Patient's age, sex, ASAgrading, previous systemic in­volvement, emergency elective surgery, surgical spe­cialty, factors related to anaesthesiologist conducting the case, time, type of anaesthesia, place and phase of occurrence of critical incident, time and means of de­tection, type and details of systemic event and sub­stantial negative outcome were recorded.

2. Analysis part: All completed forms of critical incidents includingmortality were reviewed and analyzed by senior consultant anaesthesiologist of the department. These critical incidents were later assigned to factors at­tributableto either patient or anaesthesia or surgery. When only one of these factors was responsible it was defined as "totally attributable" and ifpatient factor was associ­ated with either anaesthesiaor surgery factor itwas de­fined as "partially attributable" to anaesthesia and sur­gery respectively. Anaesthesia related critical incidents and mortality were further analyzed for factors respon­sible like equipment error, pharmacological factor and human error including lackof judgment, or skill, or ex­perience and failure to check

Data were expressed as number and proportion to calculate incidence.


During the one year study period 14,134 anaesthetics were administered and 112(0.79%) criti­cal incidents were reported with complete recovery in 80(71.42%) and mortality in 32(28.57%) cases.

Distribution of critical incidents was almost same in males and females (49.11% and 50.89% respec­tively) with a maximum incidence in 0-10 year age group (23.21%). Majority of critical incidents occurred in ASA grade I patients (n=69, 61.61%) as compared to ASAII (n=27, 24.11%) III (n=15, 13.39%) and IV (n=1, 0. 89%) patients. Incidence was maximum in pa­tients with no pre-existing systemic involvement (n=69, 61.61%) followed by cardiovascular (n=19, 16.96%) and respiratory (n=8, 7.14%) involvements. Incidents were observed more between 6am to 6pm (75.89%), in emergency patients (54.46%), and in patients ad­mitted for general surgery (43.75%), [Table 1].

Incidents occurred more frequently inpatients who received general anaesthesia (75.89%) with most of the incidents occurring in the op crating room (77.68%) or in post-operative ward (13.39%). Critical incidents occurred most commonly during the intraoperative / maintenance phase (32.04%) and frequently in the post operative period(25.89%), [Figure 1].

Majority of these incidents (98.12%) were de­tected by alert anaesthesiologists either clinically (38.39%) orby monitoring equipments (23.21%) or simultaneously by both (38.39%).

In our institution, resident doctors who are under training for postgraduation conduct cases under the su­pervision of senior consultants. Critical incidents occuied in 36 cases (32.14%) which were being conducted in­dependently by resident doctors with less than 3 years experience. In rest of the cases resident doctors were supervised by consultants with experience of 3-5 years (n=45, 40.17%) ormore than 5 years (n=41, 27.67%). There was no indication of stress among the anaesthesiologists conducting the cases. All the incidents had occuned when the workload of the anaesthesiologist was less than 12 hours, without any report of contrabut­ing factors like haste, distraction or in adequate help. Most of the critical incidents were due to events involving ei­therresp iratory system (39.29%), or cardiovascular sys­tem (32.14%) or both (9.82%), [Table 2].

From a total of 112 reported critical incidents, cardiac arrest occurred in 41 cases (36.6%, 29 per 10,000 anaesthetics) out of which 9 cases (8.03%) recovered completely and 32(28.57%) had a fatal outcome (22.6per 10,000 anaesthetics). The occur­rence of critical incidents led to postponement of sur­geiy in only 2 cases: one occurred during induction of anaesthesia (7-year-male child posted for herniotomy under general anaesthesia had hypoxia and bradycar­dia during induction leading to cardiac arrest but was resuscitated with full recovery) and the other occurred duringpronepositioning of the patient (57yearold male posted for lumbar laminectomy had paroxysmal su­praventricular tachycardia with hypotension that re­sponded to esmolol).

Critical incidents and mortality were corre­lated with factors attributable to either patient or anaesthesia or surgery. [Table 3] shows that out of 112 critical incidents maximum incidents (42.86%, n=48) were related to anaesthesia factor [Totally attributable in 40.18% (n=45) and partially attributable in 2.68% (n=3)], followed closely by patient factor (37.5%, n=42). On the contrary, out of 32 mortalities 59.38%, (n=19) were due to patient's pre-existing condition. Anaesthesia factorwas responsible for 25% (n=8) mortalities [Totally attributable 18.75% (n=6); partially attributable 6.25% (n=2)]. Respiratory events were responsible for most of the anaesthesia related critical incidents (n=32/48, 66.66%) and mortality (n=4/8,50%), [Table 4]. Human error was the most com­mon responsible factor for anaesthesia related critical incidents (n=41/48,85.41%) and mortality (n=6/ 8,75%), while equipment error and pharmacologic fac­tor were less common factors responsible, [Table 5] and [Table 6].


Internal audits based on recording ofcritical inci­dents in institutions are imperative forthe speciality of anaesthesia, firstly, to study the changes in patient out­come which underline the improvement in standards of anaesthesia care and secondly, for sharing and discuss­ingthese critical incidents to evolve new policies to pre­vent recurrences [10],[11] [12],[13]

Many variables (patient status, surgical procedure, and surgical expertise) make the delineation of anaes­thesia related factors obscure. The relative rarity of adverse outcome makes it imperative to study large number of patients overtime. The methods used to collect information about safety of anaesthesia and to establish the risk factors have included peer reviews, hospital audit, reports to medical defense societies [14] , retrospective [4] and prospective studies [15] . A prospec­tive reporting system avoids the problems of inaccu­rate recall and allows warnings and advice to be issued 'necessary, soon afterthe occurrence [15] . In ourinstitu­tion we conducted a prospective survey of 24-hour perioperative critical incidents over a one year period and found 112 critical incidents with over all incidence of 0.79% of which 0.33% (n=48) were attributable to anaesthesia. The frequency of incidents reported from different institutions have varied from 0.28% to 2.8% [16],[17] while higher incidence of 12.1% [18] and 10.6% [19] have also been reported. The vast difference in these figures lies in the fact that interpretation of critically ill in anaesthesia varies according to individual perception of an incident and to an ambiguity in how these are applied in practice. There is reluctance to report seem­ingly minor events while some major events go unre­ported for fear of retribution, lack of motivation and lack of acceptance of the fact that it could be beneficial as an educational tool [20] .

Recent studies define mortality associated with anaesthesia as death under, as a result of, orwithin 24 hour of an anaesthetic [21],[22] . In literature, crude anaes­thetic mortality(i.e. combined anaesthetic and surgical mortality) associated with anaesthesia ranges between 10-30 per 10,000 anaesthetics[23],[24],[25].It has been sug­gested that anaesthesia related mortality has decreased in the last three decades and currently ranges from 0.05 to 10 per 10,000[21],[26],[27]and in most developed coun­tries lies between 0.12-1.4 per 10,000 anaesthetics[28].

In our audit, crude anaesthetic mortality was 22.6 per 10,000 and anaesthesia related mortality was 5.6 per 10,000 anaesthetics. The reasons forhigher mortal­ity rate in our audit as compared to developed countries may be due to the fact that we do not have an effective primary and secondary health care system in our coun­try, resulting in tertiary care hospitals like ours dealing with more poorly optimized, sicker patients. Anaesthe­sia related mortality figures may well be different in the developing countries where only limited trained work force, monitoring and training facilities are available[25],[29].

Independent predictors of operative mortality cited in literature include advanced and pediatric (less than 1 year) age group as well as male gender[30],[31]. We found no correlation between sex and occurrence of critical incidents ormortalities. There was no association of mortality with age however maximum critical incidents occurred in 0-10 year age group, which shows that the paediatric population are always at risk of anaesthesia because of anatomical and physiological reasons[18],[28],[32] .

In our audit, incidence of critical incidents and mortalities was maximum in ASAl and II patients, as maximum surgical patients belonged to this physical sta­tus. In higher AS A physical status senior consultant at­tendance, stringent monitoring and extravigilance could be areason for less incidence6[6],[7],.Though some authors have found a clearrelationship between increasing ASA grade and the risk of critic al incidents particularly physi­ological incidents [18] and mortality[8],[28].

There has been a slightly higher incidence of criti­cal incidents [18] and mortalities[8],[28],[33] in emergency sur­gery as compared to elective surgery. Poor optimiza­tion of patient's pre-op erative status, non-availability of equipments, emergency drugs, investigation facilitiesand poor operating conditions are all contributory fac­tors in emergency situation in the developing countries.

Critical incidents mostly occurred during the day­ time [7] coinciding with peak working hours in our institu­tion. However it could be argued that compliance with reporting is low at late hours. General surgery patients were found more vulnerable to occurrence ofcritical in­cidents which may be due to more number ofpatients operated under general surgery, more chance of fluid and electrolyte imbalance and sepsis in these patients [6],[9]

We found in common with others that the frequency of critical incidents and mortality was higher with general than neuraxial anaesthesia[6],[28],[31] [33]. However this may be because many high risk surgeries are performed under general anaesthesia nncludungcardiac, thoracic and neu­msurgicalprocedures. Likewise there may be abias to­wards general anaesthesia in emergency settings or in patients with co-existing medical conditions. The most comprehensive recent survey of cardiac arrest incidence during neuraxial anaesthesia reported as 2.7 per 10,000 anaesthetics [33] is nearly similarto our study (3.4 per 10, 000).Impmved knowledge of neuraxial block physiol­ogy and the use of new local anaesthetics with fewer side effects, associated with more routinely used oxygen monitoring through pulse oximetty has substantially de­creasedthe possibility of major complications during neuraxial anaesthesia.

We found no correlation between occurrence of critical incidents and mortalities and experience level of anaesthesiologist [7],[32] . It has been shownthatfatigue ad­versely affects the professional performance of anaesthetists [34] . Since our resident doctors have approxi­mately an 8 hourly work schedule with an average work force of 1-2 anaesthesiologist per case, there were no reports of stress , haste, inattention, fatigue or inadequate help as reported by other workers [32],[35] .

Operating room was observed as a vulnerable site for occurrence of critical incidents [7],[9] . Induction and maintenance phase have been considered as "incident rich phase" [6],[8] but we found a higher incidence in the maintenance and post-operative phase, probably the latter could be attributable to the inadequate postop­erative monitoringand care available in our institution. However anaesthesia related incidents occurred maxi­mally during emergence and induction which are simi­larly other studies [6],[7],[9] .

Critical incidents related to airway management have been found in 17-34% of incidents [36],[37] and airway management has been shownto contribute to approxi­mately one quarter of anaesthesia related deaths [21],[22],[27] . In our auditrespiratory causes were more frequently re­sponsible for anaesthesia related critical incidents and mortality was mainly due to laryngospasm, hypoxia, esophageal intubation, bronchospasm and aspiration.

All anaesthesiologists aspire to an anaesthesia "system" that is completely safe. However, any system operated by human beings is subjectto human failure; this is both normal and inevitable [38] . Because patterns ofhuman errorin anaesthesiaas elsewhere, are identi­fiable predictable and repetitive, they lend themselves to classification and analysis [39] . From such analysis we gain a clearer understanding of how anaesthetists be­have, which is an important step in the logical evalua­tion of strategies to make such failures less common.

In our audit human error has been implicated as the major cause of anaesthesia related critical incidents [3],[4],[15],[32],[35],[40] and mortality [8],[33] . Lack ofjudgment or experi­ence, skilland failureto checkwere the most frequently reported factors for human errors. Thus there are ele­ments of human error in majority of anaesthesia related critical incidents and mortalities, although the majority of such failures were recognized and intercepted before they led to an adverse outcome. It is known that the basis for all accidents or nearaccidents in any situation is unsafe practice orworking condition [2] .

There may have been some methodological weak­ness associated with our study. Firstly, under-reporting since itwas based on adverse events being voluntarily re­ported by faculty and residents and it seems that the anaesthesiologists report major adverse events more ac­curately andfrequently ratherthan minor events. Secondly critical incidents reported in this study over a one year period represent only a proportion of all mishaps that oc­curin association with anaesthesia resulting in avert' small sample size to calculate statistical significance of risk fac­tors.

To conclude, anaesthesia continues to be associ­ated with mortality and morbidity despite improvements nl drugs and equipments. Human error is the most im­portant factor in the majority of these incidents. We emphasize that strategies and protocols should be de­veloped for increasing and updatingknowledge base to avoid errors of judgment. There is evidence that the use of checklists, protocols and unproved awareness of the relevance of critical incidents can improve safety [16] . Thus critical incidentreporting should be in­troduced in all anaesthesia departments as partof qual­ity assurance programs to ensure improved patient care.


1Philips OC, Capizzi LS. Anaesthesia mortality. Clin Anaesth 1974;10:220-224.
2Goldstein A Jr, Keats AS. The risk of anaesthesia. Anesthesio 11970;33 : 130-143.
3Flanagan JC The critical incident technique. Psychol Bulletin 1954;51: 397-358.
4Cooper JB, Newbower RS, Long CD, McPeek B. Pre­ventable anaesthesia mishaps. A study of human fac­tors. Anesthesiol 1978;49:339-406.
5Cooper JB, Newbower RS and Kitz RI. An analysis of maj or errors and equipment failures in anaesthesia man­agement: Considerations for prevention and detection. Anesthesio11984;60:34-42.
6Khan PA and Hoda MQ . Aprospective survey of intra­operative critical incidents in a teaching hospital in a developing country. Anaesth200l ; 50: 171-182.
7Manghnani PK, Shinde VS and Chaudhari LS . Critical incidents during anaesthesia `An Audit'. Ind j Anaesth 2004;48:287-294.
8Ajaj H. and Pansalovich E. "How safe is anaesthesia in Libya"? The Internet Journal ofHealth 2005;4:1-4.
9Webb RK, Currie M and Morgan CA The Australian Incident monitoring study : An Analysis of 2000 inci­dent reports. Anaesthlntens Care 1993;21:520-528.
10Van der Schaaf TW Medical applications of industrial safety science. Qua! Saf Health Care 2002;11:205-6.
11Runciman WB, Edmonds MJ, Pradhan M Setting pri­orities for patient safety. Qual Saf Health Care 2002;11:224-9.
12Runciman WB. Lessons from the Australian Patient Safety Foundation: setting up a national patient safety surveillance system-is this the right model?Qual Saf Health Care 2002;1 1:246-51.
13Beckmann U, Bohringer C, Carless R, Gillies DM, Runciman WB, Wu Av, et al. Evaluation of two meth­ods for quality improvement in intensive care: facili­tated incident monitoring and retrospective medical chart review. Crit Care Med 2003 31:1006-11.
14Utting JE, Gray TC, Shelley FC . Human misadventure in anaesthesia. Can Anaesth Soc J 1979 ; 26:472-8.
15Craig J and Wilson ME. A survey of anaesthetic misad­ventures. Anaesth 1981 36:933-936.
16Kumar \ Barcelos WA, Mehta MP, CarterJG An analy­sis of critical incidents in a teaching departm ent for qual­ity assurance. Anaesthesia 1988;43:879-83.
17Galletly DC, Mushet NN. Anaesthesia system errors. Anaesthesia andlntensive Care 1991;19:66-73.
18Maaloe R, Cour M, Hansen A, et al. Scrutinizing inci­dent reporting in anaesthesia : why is an incident per­ceived as critical? Acta Anaesthesiol Scand 2006;50:1005-1013.
19Marsh, Peter G and William DB, et al. Asurveyof 112,000 anaesthetics in one teaching hospital (1975-83). Can Anaesth Soc J 1986:33:22-31.
20Short TG, O'Regan A, Jayasuriya JP, Rowbottom M Buckley TA, Oh TB. Improvements in anaesthetic care resulting from critical incident reporting programme. Anaesthesia 1996;51:615-21.
21Tiret L, Desmonts JIM, Hatton F, Uourc'h G Complica­tions associated with anaesthesia: a prospective sur­veyinfrance. CanAnaesth Soc J 1986;33:336-334.
22Warden JC, Borton CL, Horan BF. Mortality associated with anaesthesia in NSW 1984-1990. Medical Journal of Australia 1994;161:585-593.
23HarrisonGG: Death due to anaesthesia at Groote Schuur Hospital, Cape Town 1956-87. Part 1. Incidence. South African Medical Journal 1990;77:412-415.
24Lunn IN, Devlin HB. Lessons from the confidential en­quiry into perioperative deaths in three NHS regions. Lancet 1987;2:1384-1386.
25HarrisonGG Deathdue to anaesthesia in Groote Schuur hospital, Cape Town 1956-87. Part II. Causes and changes in aetiological pattern of anaesthetic-contribu­torydeath SAfr Med J 1990;77:416-421.
26Eichhorn-JH. Prevention of intraoperative anaesthesia accidents and related severe injury through safety moni­toring. Anesthesiology 1989; 70:572-577.
27Cohen MM, Duncan PG Tweed WA, et al. The Cana­dian four-centre study of anaesthetic outcomes:I. De­scription of methods and populations. Can J Anaesth 199239:420-429.
28Braz LG, Modolo NSP and Mascimento P, et al. Perioperative cardiac arrest: a study of 53,718 anaesthetics over 9 years from a Brazilian teaching hos­pital. Br J Anaesth 2006;95 :569-75.
29Mckenzie AG Mortality associated with anaesthesia at Zimbabwean teaching hospitals. S Mr Med J 1996; 86: 338-342.
30Newland MC, Ellis SJ, Lydiatt CA, et al. Anaesthetic­ related cardiacarrest and its mortality: a report covering 72,959 anaesthetics over 10 years from a US teaching hospital. Anesthesiology 2002 97:108-15.
31Sprung J, WamerME, Contreras MG, et al. Predictors of survival following cardiac arrest in patients undergoing non-cardiac surgery: a study of 518,294 patients at a tertiary referral center. Anesthesiology 2003 ;99:259-69.
32Currie M. A prospective survey of anaesthetic critical events in a teaching hospital. Anaesth Intens Care 1989;17:403.411.
33Arbous MS, Grobbee DE, et al. Mortality associated with anaesthesia: A qualitative analysis to identify risk factors. Anaesth200l; 5:1141-1153.
34Gravenstein JS, Cooper JB, Orkin FK. Work and rest cycles in anaesthesia practice. Anesthesiology 1990;72:737-742.
35Williamson JA, Webb RK, SellenA, et al. Human failure: An analysis of 2000 incidents reports. Anaesth Intens Care 1993;21:678-683.
36Short TG O'regan A, Lew J, OH TB. Critical incident reporting in an anaesthetic department assurance programme. Anaesthesia 1993;48:3-7.
37Russell WI, WebbRK, UanDer Wilt JH, RuncimanWB. The Australian Incident Monitoring Study. Problems with ventilation: an analysis of 2000 incident reports. AnaesthlntensiveCare 1993 ;21:617-620.
38Allnutt MF. Human factors in accidents. Br J Anaesth 198759:856-864.
39Runciman WB, SellenA, Webb RK, et al. Errors, inci­dents and accidents in anaesthetic practice. Anaesth Intens Care 1993;21:506-519.
40Liu EHC and Koh KF. A prospective audit of critical incidents in anaesthesia in a university teaching hospi­tal: AnnAcadMed Singapore 2003;32:814-20.