The value of routine preoperative investigations.

In a prospective study of 400 patients admitted for elective surgery, the value of preoperative investigations in identifying the group at high risk of complications was assessed. In order to evaluate methods of reducing the number of investigations a preoperative questionnaire was used and patients were also grouped with regard to age and extent of surgery. Sixteen per cent of the results of the preoperative investigations showed some abnormality but only 0.013% caused a change in management. Abnormal results were significantly associated with complications (P less than 0.05). A positive (abnormal) questionnaire and increased age together defined a group more likely to have abnormal results (P less than 0.05) but age was a more specific indicator. The extent of surgery was not associated with abnormal results other than biochemistry results but was associated with complications (P less than 0.01) and with the need to repeat investigations postoperatively. It was concluded that a preoperative questionnaire might be useful in the assessment of day case patients, where a larger fraction would be expected to fall into the low risk group. A policy for routine preoperative investigation was drawn up. Full blood count should be performed in all patients over 40 years, ECG in all patients over 50 years and CXR and urea and electrolytes in patients over 60 years undergoing major surgery. Asymptomatic patients out with these categories do not require routine investigations.