This three-month institutional-based study was carried out at the Debre Tabor Comprehensive Specialized Hospital from May 1 to July 30, 2023. The study included all patients older than 16 years who were not pregnant and were hospitalized for elective surgery under general or regional anesthesia in the orthopedic, gynecological, and general units during the study period. The study excluded patients scheduled for emergency surgeries, day-case surgery, cardiothoracic procedures, neurosurgery, and elective procedures under local anesthesia.

We used NICE recommendations as a standard for comparison since they are internationally accepted, clear, and easily applicable guidance, even in developing nations. By recommending which investigations to offer before minor, intermediate, and major surgery while taking particular comorbidities into account, this guideline addresses standard preoperative tests to reduce unnecessary testing. Likewise, the audit focused on the tests indicated in the recommendation, including resting echocardiogram, FBC, hemoglobin A1C (HbA1c) testing, hemostasis tests, and organ function tests.

A self-administered questionnaire that was constructed in compliance with the guidelines was used to collect the data. The nights before surgery, patients were asked about possible pregnancies and any undiscovered illnesses. On the day of surgery, at the end of the procedure, data pertaining to surgical invasiveness (major, intermediate, or minor) and PI (FBC, CXR, ECG, BUN, creatinine, electrolyte, coagulation profile, kidney and liver function test) was also gathered from the patient’s medical record and compared to the guideline for appropriateness. Aside from the preoperative investigations, the patient’s sociodemographic characteristics, such as age, gender, American Society of Anesthesiologists (ASA) status, and the presence and severity of comorbid illness, were recorded. It is preferred to collect data at the end of procedures to avoid missing tests that might be performed in the morning of surgery.

In addition, the results of each investigation were recorded after being assessed as normal or abnormal, depending on the laboratory report’s normal range. The data were securely collected by two masters of sciences degree (MSc) anesthetists who were not engaged in the clinical practice of preoperative investigation requests. The information gathered was inspected for completeness and accuracy. Moreover, the data was analyzed and graphically presented using Microsoft Excel 2013.

Minor surgery: surgical procedures including Excision of skin lesion, Myringotomy tubes, Hysteroscopy and Endoscopy/Colonoscopy [21].

Intermediate surgery: surgical procedures including hernia repair, laparoscopic, cholecystectomy, arthroscopy and tonsillectomy [21].

Major surgery: surgical procedures including total abdominal hysterectomy, endoscopic resection of the prostate, lumbar discectomy, thyroidectomy, total joint replacement, lung operations, colonic resection, and radical neck dissection [21].

Recommended (appropriate) investigation: the test that is recommended to be performed or considered after consideration of the particular comorbidities, sociodemographic profile, and types of surgery [21]:

Normal value ranges were defined using the institution’s laboratory ranges.

Preoperative laboratory testing: Preoperative investigation was defined for the purposes of this audit as any component of a laboratory or imaging test performed before surgery and considered by the guidelines.