Perioperative mortality

Perioperative mortality is death in relation to surgery, most frequently defined for research purposes as death within 24 hours, or alternatively within up to 30 days of a surgical procedure. An important consideration in the decision to perform any surgical procedure is to weigh the benefits against the risks. Anesthesiologists and surgeons employ various methods in assessing whether a patient is in optimal condition from a medical standpoint prior to undertaking surgery, and various statistical tools are available. ASA score is the most well known of these.

Intraoperative causes

Immediate complications during the surgical procedure, e.g. bleeding or perforation of organs may have lethal sequelae.

Complications following surgery

Infection

Local infection of the operative field is prevented by using sterile technique, and prophylactic antibiotics are often given in abdominal surgery or patients known to have a heart defect or mechanical heart valves that are at risk of developing endocarditis.

Methods to decrease surgical site infections in spine surgery include skin preparation, use of surgical drains, prophylactic antibiotics, and vancomycin.^[1] Preventative antibiotics may also be effective.^[2]

Whether any specific dressing has an effect on the risk of surgical site infection of a wound that has been sutured closed is unclear.^[3]

Blood clots

Examples are deep vein thrombosis and pulmonary embolism, the risk of which can be mitigated by certain interventions, such as the administration of anticoagulants (e.g., warfarin or low molecular weight heparins), antiplatelet drugs (e.g., aspirin), compression stockings, and cyclical pneumatic calf compression in high risk patients.

Lungs

Many factors can influence the risk of postoperative pulmonary complications (PPC). (A major PPC can be defined as a postoperative pneumonia, respiratory failure, or the need for reintubation after extubation at the end of an anesthetic. Minor post-operative pulmonary complications include events such as atelectasis, bronchospasm, laryngospasm, and unanticipated need for supplemental oxygen therapy after the initial postoperative period.) ^[4] Of all patient-related risk factors, good evidence supports patients with advanced age, ASA class II or greater, functional dependence, chronic obstructive pulmonary disease, and congestive heart failure, as those with increased risk for PPC.^[5] Of operative risk factors, surgical site is the most important predictor of risk for PPCs (aortic, thoracic, and upper abdominal surgeries being the highest-risk procedures, even in healthy patients.^[6] The value of preoperative testing, such as spirometry, to estimate pulmonary risk is of controversial value and is debated in medical literature. Among laboratory tests, a serum albumin level less than 35 g/L is the most powerful predictor and predicts PPC risk to a similar degree as the most important patient-related risk factors.^[5]

Respiratory therapy has a place in preventing pneumonia related to atelectasis, which occurs especially in patients recovering from thoracic and abdominal surgery..

Neurologic

Strokes occur at a higher rate during the postoperative period.

Livers and kidneys

In people with cirrhosis, the perioperative mortality is predicted by the Child-Pugh score.

Postoperative fever

Postoperative fevers are a common complication after surgery and can be a hallmark of a serious underlying sepsis, such as pneumonia, urinary tract infection, deep vein thrombosis, wound infection, etc. However, in the early post-operative period a low-level fever may also result from anaesthetic-related atelectasis, which will usually resolve normally.

Epidemiology

Most perioperative mortality is attributable to complications from the operation (such as bleeding, sepsis, and failure of vital organs) or pre-existing medical conditions.. In high-resource health care systems, statistics are often kept by mandatory reporting of perioperative mortality. These may then be used in league tables that compare the quality of hospitals. Critics of this system point out that perioperative mortality may not reflect poor performance but could be caused by other factors, e.g. a high proportion of acute/unplanned surgery, or other patient-related factors. Most hospitals have regular meetings to discuss surgical complications and perioperative mortality. Specific cases may be investigated more closely if a preventable cause has been identified.

Globally, there are few studies comparing perioperative mortality across different health systems. One major prospective study of 10,745 adult patients undergoing emergency abdominal surgery from 357 centres in 58 high-, middle-, and low-income countries found that mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors.^[7] In this study the overall global mortality rate was 1·6 per cent at 24 hours (high 1·1 per cent, middle 1·9 per cent, low 3·4 per cent; P < 0·001), increasing to 5·4 per cent by 30 days (high 4·5 per cent, middle 6·0 per cent, low 8·6 per cent; P < 0·001). Of the 578 patients who died, 404 (69·9 per cent) did so between 24 h and 30 days following surgery (high 74·2 per cent, middle 68·8 per cent, low 60·5 per cent). Patient safety factors were suggested to play an important role, with use of the WHO Surgical Safety Checklist associated with reduced mortality at 30 days.

Taking a similar approach, a unique global study of 1,409 children undergoing emergency abdominal surgery from 253 centres in 43 countries showed that adjusted mortality in children following surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed in these settings. Internationally, the most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries. ^[8]

Mortality directly related to anesthetic management is less common, and may include such causes as pulmonary aspiration of gastric contents,^[9] asphyxiation^[10] and anaphylaxis.^[11] These in turn may result from malfunction of anesthesia-related equipment or more commonly, human error. A 1978 study found that 82% of preventable anesthesia mishaps were the result of human error.^[12]

In a 1954 review of 599,548 surgical procedures at 10 hospitals in the United States between 1948 – 1952, 384 deaths were attributed to anesthesia, for an overall mortality rate of 0.064%.^[13] In 1984, after a television program highlighting anesthesia mishaps aired in the United States, American anesthesiologist Ellison C. Pierce appointed a committee called the Anesthesia Patient Safety and Risk Management Committee of the American Society of Anesthesiologists.^[14] This committee was tasked with determining and reducing the causes of peri-anesthetic morbidity and mortality.^[14] An outgrowth of this committee, the Anesthesia Patient Safety Foundation was created in 1985 as an independent, nonprofit corporation with the vision that "no patient shall be harmed by anesthesia".^[15]

The current mortality attributable to the management of general anesthesia is controversial.^[16] Most current estimates of perioperative mortality range from 1 death in 53 anesthetics to 1 in 5,417 anesthetics.^[17][18] The incidence of perioperative mortality that is directly attributable to anesthesia ranges from 1 in 6,795 to 1 in 200,200 anesthetics.^[17] There are some studies however that report a much lower mortality rate. For example, a 1997 Canadian retrospective review of 2,830,000 oral surgical procedures in Ontario between 1973 – 1995 reported only four deaths in cases in which either an oral and maxillofacial surgeon or a dentist with specialized training in anesthesia administered the general anesthetic or deep sedation. The authors calculated an overall mortality rate of 1.4 per 1,000,000.^[19] It is suggested that these wide ranges may be caused by differences in operational definitions and reporting sources.^[17]

The largest study of postoperative mortality was published in 2010. In this review of 3.7 million surgical procedures at 102 hospitals in the Netherlands during 1991 – 2005, postoperative mortality from all causes was observed in 67,879 patients, for an overall rate of 1.85%.^[20]

Anaesthesiologists are committed to continuously reducing perioperative mortality and morbidity. In 2010, the principal European anaesthesiology organisations launched The Helsinki Declaration for Patient Safety in Anaesthesiology, a practically-based manifesto for improving anaesthesia care in Europe.

See also

• Patient safety
• ASA physical status classification system

References

Further reading

• Deans, GT; Odling-Smee W; McKelvey ST; Parks GT; Roy DA (1987). "Auditing perioperative mortality". Ann R Coll Surg Engl. 69 (4): 185–7. PMC 2498471 . PMID 3631878. 
• Fong, Y; Gonen M; Rubin D; Radzyner M; Brennan MF (2005). "Long-term survival is superior after resection for cancer in high-volume centers". Ann Surg. 242 (4): 540–4. PMC 1402350 . PMID 16192814. 
• Johnson, ML (2002). "Effect of Definition of Mortality on Hospital Profiles". Medical Care. 40: 7–16. JSTOR 3767954. doi:10.1097/00005650-200201000-00003. 
• Mayo, SC; Mayo SC; Shore AD; Nathan H; Edil BH; Hirose K; Anders RA; Wolfgang CL; Schulick RD; Choti MA; Pawlik TM (2011). "Refining the definition of perioperative mortality following hepatectomy using death within 90 days as the standard criterion". HPB (Oxford). 13 (7): 473–82. PMC 3133714 . PMID 21689231. doi:10.1111/j.1477-2574.2011.00326.x. 
• Nixon, SJ (1992). "NCEPOD: Revisiting perioperative mortality" (PDF). BMJ. 304: 1128–1129. doi:10.1136/bmj.304.6835.1128. 
• Ponz de Leon, M; Pezzi A; Benatti P; Manenti A; Rossi G; di Gregorio C; Roncucci L (2009). "Survival, surgical management and perioperative mortality of colorectal cancer in the 21-year experience of a specialised registry". International Journal of Colorectal Disease. 24 (7): 777–88. PMID 19280201. doi:10.1007/s00384-009-0687-1. 
• Shaw, CD (1990). "PERIOPERATIVE AND PERINATAL DEATH AS MEASURES FOR QUALITY ASSURANCE". International Journal for Quality in Health Care. 2 (3–4): 235–41. doi:10.1093/intqhc/2.3-4.235. 
• Simunovic, N; Devereaux P; Bhandari M (2011). "Surgery for hip fractures: Does surgical delay affect outcomes?". Indian J Orthop. 45 (1): 27–32. PMC 3004074 . PMID 21221220. doi:10.4103/0019-5413.73660. 
• Start RD, Cross SS, Start RD, Cross SS; Start RD, Cross SS, Start RD, Cross SS (1999). "Acp. Best practice no 155. Pathological investigation of deaths following surgery, anaesthesia, and medical procedures". J Clin Pathol. 52 (9): 640–52. PMC 501538 . PMID 10655984. doi:10.1136/jcp.52.9.640. 
• Schermerhorn, ML; Giles, KA; Sachs, T; Bensley, RP; O'Malley, AJ; Cotterill, P; Landon, BE (2011). "Defining Perioperative Mortality after Open and Endovascular Aortic Aneurysm Repair in the US Medicare Population". Journal of the American College of Surgeons. 212 (3): 349–55. PMC 3051838 . PMID 21296011. doi:10.1016/j.jamcollsurg.2010.12.003. 

External links

• Perioperative Mortality Review Committee, Department of Health, New Zealand (2009). "Terms of Reference for the Perioperative Mortality Review Committee" (PDF). CS1 maint: Multiple names: authors list (link)
• "National Confidential Enquiry into Patient Outcome and Death".