A Comparison of the Effect of Isoflurane and Propofol on Liver Enzymes

Isoflurane and propofol are routinely used for the maintenance of general anaesthesia. However, recently, they have been implicated in hepatotoxicity resulting in acute liver failure.

We compared the effects of isoflurane and propofol on liver enzymes; aspartate transaminases (AST), alanine transaminases (ALT), alkaline phosphatase (ALP) and total bilirubin (Tbil) following general anaesthesia.

This randomized, controlled clinical trial involved 60 ASA I and II patients aged 18-64 years scheduled for elective surgery requiring general anaesthesia. Anaesthesia was induced with intravenous sodium thiopentone 5 mg/kg and atracurium 0.5 mg/kg, and maintained in group I with isoflurane (MAC, 0.8%-1.5%) and in group P with (propofol infusion, 100-200µg/kg/minute). Blood samples were taken pre-induction, immediate- and 24 hours post operatively. The serum levels of AST, ALT, ALP, Tbil were analyzed and compared in both groups. Risk factors for post operative hepatotoxicity were determined.

Propofol caused a significant reduction in ALP (P = 0.005) but increase in Tbil (P = 0.010) 24 hours postoperatively. Though isoflurane had consistently higher values of AST, ALP and Tbil than propofol, only the mean AST values at 24 hours post-operative was significantly higher (P = 0.045). There was a significant increase in the 24 hours post-operative Tbil following massive blood loss; [odd ratio 23.91, 95%, CI (1.685-339.315)], P = 0.019.

Both agents had a varied effect on liver enzymes. Isoflurane resulted in a significantly higher increase in 24 hours post-operative serum AST than propofol. Propofol caused a significant increase in 24 hours post-operative total bilirubin. Caution is therefore recommended in their use in patients with altered liver enzymes.