Hepatic function after anaesthesia for major vascular reconstructive surgery

Eltanolone for induction of anaesthesia in the surgical patient. A comparison of dose requirements in young and elderly patients

BACKGROUND

The relative potency of the steroid anaesthetic agent eltanolone has been compared with respect to induction of anaesthesia in ASA I and II young (18-40 years) and elderly (> 65 years) patients.

METHOD

113 temazepam premedicated patients (60 elderly) were evaluated in an open randomised study. They were allocated to receive doses between 0.05 and 0.75 mg/kg given i.v. over 30 s. The first 33 patients formed a pilot phase; the formal study comprised 80 patients. The primary efficacy variable was loss of verbal contact within 120 s and an effect lasting more than 4 min. All patients breathed 100% oxygen throughout the study period. Safety data (heart rate, blood pressure, respiratory apnoea, involuntary movements, hypertonus and other adverse effects) were noted.

RESULTS

Anaesthesia was adequately induced in 12/40 elderly and 7/40 young patients. The lowest effective induction dose was 0.2 mg/kg in elderly and 0.3 mg/kg in young patients. This gave a relative potency of 0.28 (95% CI 0.12-0.52; P = 0.0039). The cardiovascular effects associated with induction were small; other side-effects included involuntary movement and hypertonus, and respiratory upsets (apnoea, hiccups and coughing).

CONCLUSION

The effective induction dose of eltanolone was significantly lower in the elderly patients; but the drug safety profile was similar in both age groups of patients.

[Diprivan and liver]

No evidence of hepatoxicity has been demonstrated with propofol. Propofol can be used for anaesthesia in patients suffering from moderate cirrhosis of the liver. Liver blood flow is preserved. Propofol dosage must be titrated to each patient's needs. Data concerning the use of propofol in patients suffering from severe hepatic failure or cholestasis are lacking. Propofol dosage in chronic alcoholic patients without cirrhosis must be increased.

Rapid halogenated hydrocarbon toxicity in isolated hepatocytes is mediated by direct solvent effects

The toxicity of several halogenated and non-halogenated hydrocarbons (CH2Cl2, CHCl3, CCl4, C6H14, C8H10) in isolated rat hepatocytes were compared. Release of aspartate aminotransferase (AST) activity was rapid and concentration-dependent. Fractional AST release plateaued at 10-60 min following hydrocarbon exposure. Enzyme leakage at 60 min correlated with the oil/water partition coefficient (pi) of the compounds. All compounds, except n-hexane, also caused an immediate inhibition of the rate of cellular respiration. Inhibition of cell respiration also correlated with pi and was reversible. The recovery of cellular oxygen consumption was examined in detail for CCl4 and correlated with evaporation of the compound. These data suggest that acute hydrocarbon-induced injury in isolated hepatocytes is mediated by concentration-dependent direct solvent effects. Since halogenated hydrocarbons are widely used to induce general anesthesia, the clinical implications of possible direct effects by halocarbons on liver function in vivo and the potential relationship to liver injury are discussed.