• All patients who needed observation, ventilatory support in the postoperative period.

• All patients who needed Anaesthesia Intensive care in view of compromised hemodynamic and metabolic status.

• Patients with postoperative complications arising more than forty eight hours after primary surgery.

Exclusion criteria: Paediatric, cardiac and neurosurgical patients in view of separate intensive care unit

Postoperative review of every patient was carried out to determine the cause for post operative admission in the uninformed group. These patients were further divided into four major categories:

Category 1: Related to central nervous system

• Unexpected depressed level of consciousnes

• New cerebrovascular accident.

Category 2: Related to cardiovascular system

• Pulmonary Edema

• Prolonged hypotension requiring inotropic support

• Arrhythmias

• Cardiac Arrests

Category 3: Related to respiratory system

• Respiratory depression

• Low pO2, high pCO2

• Atelectasis / Pneumonia

• Airway obstruction

Category 4: Related to metabolic system

• Fluid disturbances

• Electrolyte imbalances

Age and sex: The maximum numbers of admissions were for the older age group more than 60 years and males aged more than 60 years accounted for the majority of the cases. This is a well established fact.₂ Males have more co existing diseases in comparison to females. The morbidity and mortality was high in elderly surgical patients. The reason behind this might be the fact that multi organ functional reserve reduces with age and associated medical problems. The common causes of morbidity in elderly are Hypertension, Diabetes Mellitus, Coronary Artery Disease, Chronic renal, hepatic, pulmonary disorders and metabolic derangements in sequence, all of which increase the risk of anaesthesia inspite of medical therapy.₃, ₄

ASA grading: Admissions of patients with poor physical status and poor ASA grading based on the severity of systemic illness increases the chances of intensive care unit admissions as shown in our study.

Surgical procedures: Those procedures associated with general surgery increases the risk of morbidity and mortality. Maximum number of patients were operated for abdominal explorations as compared to other surgical branches like orthopedic, plastic, obstetric, gynaecological procedures. Moreover, the surgical determinants of peri operative morbidity have been shown to be associated with major procedures, especially abdominal surgery.₅

Anaesthesia technique: Leigh and Tytler have said that greater vigilance on the part of the anaesthesiologist can prevent most of the complications arising because of anaesthesia or during anaesthesia.₆ In our study, 97.6% of the total 207 patients admitted to anaesthetic intensive care unit in the post operative period had been administered General anaesthesia, while only 1.9% of patients had been administered regional anaesthesia for surgery. Worldwide, the best anaesthetic technique is controlled balanced anaesthesia with General anaesthesia, though it has controversies.₇ In a study of Cohen et al of 100,000 anaesthesia regimens performed in Canada, the choice of anaesthesia did not provide any additional prognostic information for predicting mortality beyond that of patient disease and the surgical procedure.₄ However, there has been a series of randomized controlled trials that demonstrate improved outcome of regional anaesthetic technique as compared with General anaesthesia.

Nature of surgery: All patients undergoing major or emergency surgery have an increased risk of severe adverse outcomes, including increased mortality.₃ Emergency surgery has an additional risk because the preparation of the patient is not optimum. There is minimal time for correctable majors like correction of electrolyte imbalance, blood parameters, dehydration and acidosis, and the patient is in a compromised health status.₁₁In our study, out of 207 patients, 118 (67%) were emergency cases. Increased vigilance and help for the anaesthesiologist should be taken care of in emergency situations by the administrative authorities. Duration of anaesthesia may reflect the severity of underlying surgical diseases because a major surgery and longer duration of anaesthesia may change the physiology and have an adverse effect on outcome.

Intensive care unit admissions: In our study 198 (95.7%) patients out of the total number of post operative intensive care unit admissions were informed prior and the remaining 9 (4.3%) admissions were uninformed. The reasons for uninformed admissions were multifactorial. We found that respiratory disturbances accounted for 22.2%, cardiovascular disturbances for 33.3% and central nervous system disturbances for 44.5%. Keith Rose and colleagues also found that respiratory events were the main reason for uninformed critical care admissions and ventilatory management.₈ Swann et al have studied the rationale of predictability and preventability of unplanned intensive care unit admissions. ₁₀

Duration of intensive care unit stay: Anaesthesiologists have considered intensive care unit stay on the basis of ASA physical status, medical illness, expected blood loss, duration of anaesthesia, need of ventilatory support, airway problems and other expected complications.₉ Intra operative complications like major blood loss, presence of arrhythmias, and hypotension with inotropic support were found in both informed and uninformed groups, elective and emergency groups. Keith Rose et al have noted that if percent oxygen saturation is less than 90% pre operatively, mechanical ventilation is required and post operative intensive care unit admission rate is 2.2%.₈ David Swann and colleagues also reported post operative admission rate of 1.4 % for mechanical ventilation in both planned and unplanned groups.₁₀

Forrest et al said that the major risk factors were cardio vascular, thoracic and abdominal surgery, history of cardiac failure, myocardial infarction or hypertension, age more than 50 years, ASA physical status III or IV.₅ In our study, the major risk factors were emergency and abdominal surgeries. Pederson et al have done a prospective study of mortality associated with anaesthesia and surgery – risk indicators of mortality in hospital – the risk of death associated with anaesthesia is known to depend on a number of factors which may be determined intra- or pre operatively.₉ Derrington and Smith et al have studied anaesthetic risk, morbidity and mortality.₂

The number of patient at increased risk of anaesthesia is reducing because of improved quality and care in anaesthetic practice. 27 patients in our study were admitted to the anaesthesia intensive care unit for intensive monitoring alone and did not receive any intervention. This is of the same order as the 20-40% incidence of low risk monitoring admissions reported by other intensive care units.₁₀

Intermediate care area means those patients are admitted who need low risk monitoring so the occupancy of anaesthesia intensive care unit beds will be reduced and will be available for the high risk patients.₁₂

1. We are thankful to Dr. Neelima Kshirsagar, Dean, Seth G. S. Medical College and K.E.M Hospital for permitting us to carry out this study and publish this paper.

2. We are thankful to the staff members and resident doctors of Department of Anaesthesiology for their support in conducting this study.

3. We are thankful to Dr. Kadam, Lecturer, Dept. of Preventive and Social Medicine, K.E.M. Hospital, for helping us with performing the statistical calculations.