Relevance of routine preoperative testing in ASA grade 1 and 2 patients undergoing minor to moderate elective surgeries at Kenyatta national hospital

Abstract

BACKGROUND Several studies and guidelines have recommended avoiding routine preoperative testing in American Society of Anaesthesiologists (ASA) grade 1 and 2 patients undergoing minor to moderate elective surgeries. However, most of these studies were conducted in developed countries. At Kenyatta National Hospital, routine preoperative tests are done on all patients undergoing elective surgery at the main theatre regardless of grade of surgery or ASA grade. This study was done to find out if routine testing does actually reveal any additional information other than findings on history and physical examination in our setup. This data was used to determine if we can develop local guidelines similar to those in the developed countries. OBJECTIVE To evaluate the usefulness of routine preoperative testing in ASA grade 1 and 2 patients undergoing minor to moderate elective surgeries at the main theatre at Kenyatta National Hospital. METHODOLOGY A cross sectional study of 166 consenting ASA grade 1 and 2 patients undergoing minor to moderate surgeries at the Kenyatta National Hospital main theatre was conducted after approval from the University of Nairobi (UON) / Kenyatta National Hospital (KNH) Ethics and Research Committee. The study was conducted over three and a half months. Data was gathered using pre tested questionnaires on abnormal results, consequences of abnormal results on immediate perioperative management and number of times preoperative tests are conducted. Discrete variables were analyzed using percentages and frequencies while continuous variables were analyzed using measures of central tendency. Results were then compared to previous studies from developed countries using chi square, and p values obtained. 10 RESULTS The study reviewed preoperative tests of 166 patients. The mean age of the sample was 40 years (SD 13), of which 55.4 % were male. 58.4 % were classified as ASA grade 1 while 93.4 % underwent a grade 2 surgery. Anaemia was prevalent in 6.6 % (p value 0.363) of the patients, 6.6 % (p value 0.00001) had a leukocytosis, 3 % (p value 0.0092) had thrombocytopenia, 4.8 % (p value 0.056) had an abnormal urea, 6.6 % (p value 0.00066) had an abnormal creatinine and around 4 % (p value 0.0032) had an abnormal electrolyte level. 25 patients had a repeat test done, although all their tests were within normal range. Out of the 55 % patients who had an abnormality on their preoperative test only 4.2 % (p value 0.2615) had their surgery postponed while 3 % had additional investigations. CONCLUSION The incidence of abnormal routine preoperative tests in our population is higher than that in developed countries, however, the rate at which it impacts perioperative management is not different. This study alludes to the possibility of developing local guidelines similar to those from developed countries.