Hepatic Injury Following Elective Craniotomy Surgery- A Prospective Observational Study

Post-operative liver injury refers to the spectrum of abnormal liver biochemical tests. Their occurrence is attributed to surgical positioning, hypotension, or the drugs.1 The assessment of the biochemical parameters such as AST, ALT, and bilirubin indicates the damage to hepatocytes or biliary flow system. The increase in amount of the these parameters from their baseline values help quantify the severity of liver injury into mild, moderate and severe.1 The guidelines on the management of abnormal liver blood tests commissioned by the Clinical Services and Standards Committee (CSSC) of the British Society of Gastroenterology (BSG) recommends that the patients with abnormal liver blood tests should be considered for investigation with a liver etiology screen irrespective of level and duration of abnormality.2The incidence of post operative hepatitis after craniotomy surgeries are unknown. There are few case reports of post-operative hepatitis which was attributed to surgical positioning, and anesthetic agents.3,4 Positions such as prone can lead to hypotension and hypoperfusion to liver tissues leading to hepatic injury. Neurosurgeries are often of long duration and involve surgical position other than supine (prone, lateral, sitting etc.). These factors may contribute towards hepatic injury. However, the data regarding the occurrence of such complications in neurosurgical cases are not robust. Therefore, we are conducting this study to find out the occurrence of hepatic injury after elective craniotomy. Our primary objective is to find out the occurrence of hepatic injury after elective craniotomy surgery. Our Secondary Objective is to find out various perioperative factors associated with liver injury in elective craniotomy patients.

Prior to surgery written and informed consent for the study will be taken from all patients. Pre-operative baseline blood investigations will be sent, which includes hemogram, PT(INR), urea, creatinine, sodium, potassium, calcium, creatinine kinase, transaminase (AST) and alanine transaminase (ALT) Lactate Dehydrogenase (LDH) alkaline phosphatase and serum bilirubin. On the day of surgery all patients will receive their scheduled medications. Standard monitors of ECG, noninvasive blood pressure, and pulse oximeter will be   attached and patients will be preoxygenated with 100% oxygen for 3 minutes at a fresh gas flow of 6 lits/ min. General anesthesia will be induced with fentanyl and propofol followed by rocuronium to facilitate tracheal intubation.  As per the requirement in the particular case a standard protocol of inhalational/ intravenous anesthesia will be followed in all patients.  In the intraoperative period continuous invasive blood pressure, end tidal carbon dioxide (ETCO2), central venous pressure, nasophayngeal temperature, minimum alveolar concentration of inhalational agents will be monitored. The intraoperative hemodynamic parameters will be maintained within 20% of the baseline values and euthermia and euvolemia will be maintained. Arterial blood gas analysis will be done as and when necessary. The total duration of anesthesia and surgery will be noted. Tracheal extubation will be done as per the discretion of the attending anesthesiologist. Serum electrolytes (sodium, potassium and calcium), urea and creatinine, PT(INR), creatinine kinase, AST, ALT, LDH, alkaline phosphatase and serum bilirubin will be measured in after the patient is shifted to the ICU following the surgery.

In the post operative period, serum electrolytes, urea, creatinine, PT(INR), creatinine kinase, AST, ALT, LDH, alkaline phosphatase and serum bilirubin will be measured daily till 72 hours after surgery. In the post operative period, patients will be managed as per the standard post operative management protocol in the ICU or ward.  The renal injury staging will be done daily from first post operative day till 3 days post operatively using AKIN staging system.  Any degree of liver or kidney injury detected during the study period will be managed as appropriate. The total duration of ICU and hospital stay of the patients will be noted.   Neurological outcome at discharge will be assessed with Glasgow outcome scale (GOS).