|Year : 2007 | Volume
| Issue : 4 | Page : 267
Perioperative risk assessment and decision making
Editor, IJA, India
|Date of Web Publication||20-Mar-2010|
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Bajaj P. Perioperative risk assessment and decision making. Indian J Anaesth 2007;51:267
The administration of anesthesia is an extremely safe procedure today. Data published by the American Society of Anesthesiology tell us that the risk of anesthesia-related death has decreased 25-fold since 1970, from 1 in 10,000 to 1 in 250,000. In the USA, this risk reduction has closely followed a second trend, namely, a doubling of the number of working anaesthesiologists. All this has occurred during a time when the youngest of premature infants in neonatal units survives intricate, lifesaving procedures and 100-year-old patients undergo and recover from major surgeries that were once thought to be impossible. Today, safety in anaesthesia is comparable to safety in aviation, i.e. the risk of an aviation accident per departure is 0.96 in 1,000,000 for scheduled passenger operations(about 145 million departures during the last 10 years) and 2.64 in 1,000,000 for other operations (charter, cargo, demonstration, etc-about 25 million departures during the last ten years)  . Considering the greater number of deaths involved in a passenger aircraft crash, undergoing anaesthesia is actually safer than flying !
How can safety in anaesthesia be kept as high as it is, or even improved? Apart from the above mentioned greater expertise of personnel performing anaesthesia, the development of useful monitoring techniques, and proper risk assessment, particularly before more difficult procedures in elderly patients and in patients suffering from diverse concomitant disease, may help to maintain a high safety standard even in high risk surgery.
The overall anaesthesia and surgery-related mortality rate within the 30 days following an operation is 1.2%, compared to approximately 6% inpatients over 80 years , . Clearly, age>70-75 years is an independent factor predicting the incidence of death or myocardial infarction  . The risk of respiratory failure has been found to be 1.5 times higher in patients>60 years, and 1.9 times higher in patients>70 years  . One of the factors that make anaesthesia more risky in elderly patients is age-related co-morbidity, particularly with respect to the central nervous system, heart, ventilatory system and kidneys. The majority of patients over the age of 70 years have some degree of cerebral atrophy  .
The question arises whether the anaesthesiologists can actively reduce perioperative risk in the elderly patient cohort by a specific anaesthesia management. Perhaps the primary decision that has to be made is whether general or regional anaesthesia should be applied.
Other measures have proved to be more successful in reducing the risk of postoperative cognitive dysfunction in elderly patients. Early surgery, oxygen administration, prevention of blood pressure drops, and immediate treatment of postoperative complications were able to reduce the rate of acute confusional states from 61.3% to 47.6%, and the hospital stay from 17.4 to 11.6 days  .
The assessment of cardiac risk in anaesthesia was the subject of several early studies in the field of anaesthesiology.
Several more studies were performed to improve the accuracy with which cardiac risk can be predicted , . It was found that onlyfive to six factors correlate well with cardiac complications rates or mortalityin the perioperative period. In one study, these included age>70 years, diabetes mellitus, anamnesis of myocardial infarction, angina pectoris and congestive heart failure. In another study, they included, anamnesis of coronary heart disease, high-risk surgery, serum creatinine>2mg.dL -1 , diabetes mellitus, anamnesis of TIA or stroke and congestive heart failure , . The presence of more than three risk factors was associated with a complication rate of 18% and 11%, respectively, in these two studies , . Regardless of the fact that clinical markers are what allow us to estimate cardiac risk quite accurately, the question arises whether further cardiac diagnosis should be performed before elective surgery. A study in 878 patients revealed an algorithm to determine the status of the coronary arteries from anamnesis and clinical and laboratory findings  .
Other tests for determining cardiac risk, such as stress echocardiography, bicycle ergometry or thallium scintigraphy, have been shown to have a relatively high sensitivity (80-90%), but a rather low specifity (around 70%) ,, .An exact diagnosis of coronary artery disease still requires coronary artery angiography. The main question that arises from all prognostic markers of cardiac risk is whether any measures can be taken to reduce this risk before the patient is scheduled for an elective surgical procedure. Today, standard treatment regimens for coronary artery disease are â-blockade, coronary angioplasty or stent implantation and coronary artery bypass graft. In several studies, â-blockade has proved to be useful in preventing perioperative ischaemic events and in reducing mortality, even in cases where relative contraindications to this therapy existed (chronic obstructive pulmonary disease, diabetes mellitus and peripheral artery occlusive disease) ,,, .
For coronary artery bypass grafting, the risk reduction has only been proved for subsequent major surgery, not for other types of surgery  . Preoperative coronary angioplasty did not seem to be an efficient measure for reducing perioperative cardiac risk in noncardiac surgery  .
Assessment of pulmonary risk factors prior to surgical procedures may be performed with spirometric lung function data in combination with physical performance, blood gas analysis and pulmonary anamnesis ,, . Apart from other factors, a pneumonia and respiratory risk reduction by 39%, and 59%, respectively, have been found in a meta-analysis that included 141 trials in 9559 patients  . To avoid perioperative risk, the use of combined general and regional anaesthesia has proven very effective  .
| References|| |
|1.||Boeing 2003 Statistical Summary, May 2004. |
|2.||Pedersen T, Eliasen K, Henriksen E.Aprospective study of mortality associated with anaesthesia and surgery: risk indicators of mortality in hospital. Acta Anaesthesiol Scand 1990;34:176-182. |
|3.||Djokovic JL, Hedley-Whyte J. Prediction of outcome of surgery and anesthesia in patients over 80. JAMA 1979; 242:2301-2306. |
|4.||L'Italien GJ, Paul SD, Hendel RC, et al. Development and validation of a Bayesian model for perioperative cardiac risk assessment in a cohort of 1081 vascular surgical candidates. JAm Coll Cardiol 1996;27:779-786. |
|5.||Arozullah AM, Daley J, Henderson WG, Khuri SF. Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. The National Veterans Administration Surgical Quality Improvement Program. Ann Surg 2000;232:242-253. |
|6.||LeMay M. Radiologic changes of the aging brain and skull.Am J Roentgenol 1984;143:383-389. |
|7.||Gustafson Y, Brannstrom B, Berggren D, et al. A geriatric-anesthesiologic program to reduce acute confusional states in elderly patients treated for femoral neck fractures. J Am Geriatr Soc 1991;39:655-662. |
|8.||Paul SD, Eagle KA, Kuntz KM, et al. Concordance of preoperative clinical risk with angiographic severity of coronary artery disease in patients undergoing vascular surgery. Circulation 1996;94;1561-1566. |
|9.||Lee TH, Marcantonio ER, Mangione CM, et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation 1999;100:1043-1049. |
|10.||Boersma E, Poldermans D, Bax JJ, et al. DECREASE Study Group (Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography). Predictors of cardiac events after major vascular surgery:role of clinical characteristics, dobutamine echocardiography, and beta-blocker therapy. JAMA 2001;285:1865-1873. |
|11.||Gauss A, Rohm HJ, Schauffelen A, et al. Electrocardiographic exercise stress testing for cardiac risk assessment in patients undergoing noncardiac surgery. Anesthesiology 2001;94:38-46. |
|12.||Chassot PG, Delabays A, Spahn DR. Preoperative evaluation of patients with, or at risk of, coronary artery disease undergoing noncardiac surgery. Br J Anaesth 2002;89:747-759. |
|13.||Wallac A, Layug B, Tateo I, et al. Prophylactic atenolol reduces postoperative myocardial ischemia. McSPI Research Group. Anesthesiology 1998;88:7-17. |
|14.||Mangano DT, Layug EL, Wallace A, Tateo I, et al. Effect of atenolol on mortality and cardiovascular morbidity after noncardiac surgery. Multicenter Study of Perioperative Ischemia Research Group. N Engl J Med 1996;335:1713-1720. |
|15.||Poldermans D, Boersma E, Bax JJ, et al. The effect of bisoprolol on perioperative mortality and myocardial infarction in high-risk patients undergoing vascular surgery. Dutch Echocardiographic Cardiac Risk EvaluationApplying Stress Echocardiography Study Group. N Engl J Med 1999;341:1789-1794. |
|16.||Eagle KA, Rihal CS, Mickel MC, et al. Cardiac riskofnoncardiac surgery: influence of coronarydisease and type ofsurgeryin 3368 operations. CASS Investigators and University of Michigan Heart Care Program. CoronaryArtery Surgery Study. Circulation 1997;96:1882-1887. |
|17.||Godet G, Riou B, Bertrand M, et al. Does preoperative coronary angioplasty improve perioperative cardiac outcome ? Anesthesiology 2005;102:739-746. |
|18.||Gruber EM, Tschernko EM.Anaesthesia and postoperative analgesia in older patients with chronic obstructive pulmonary disease. Drugs Aging 2003;20:347-360. |
|19.||Tschernko E, Kritzinger M, Gruber E, et al. Lung volume reduction surgery: preoperative functional predictors for postoperative outcome.Anesth Analg 1999;88:28-33. |
|20.||Linden PA, Bueno R, Colson YL, et al. Lung resection in patients with preoperative FEV1<35% predicted. Chest 2005;127:1984-1990. |
|21.||RodgersA, Walker N, Schug S, et al. Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomized trials. BMJ 2000;321:1493. |