The effect of N-acetylcysteine on oxygen transport and uptake in patients with fulminant hepatic failure

✍ Scribed by Timothy S. Walsh; Patrick Hopton; Barbara J. Philips; Simon J. Mackenzie; Dr. Alistair Lee

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 167 KB
• Volume: 27
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.510270520

✦ Synopsis

We have investigated the effect of N-acetylcysteine on hemodynamic variables, oxygen delivery (DO 2 ), oxygen consumption (VO 2 ), and oxygen extraction in patients with fulminant hepatic failure using independent methods of determining DO 2 and VO 2 , thereby eliminating the effect of mathematical coupling, which may have biased previous studies. In 11 patients with severe fulminant hepatic failure, we documented the hemodynamic effects of N-acetylcysteine during the first 5 hours of a standard infusion regime and simultaneously measured VO 2 using a method based on respiratory gas analysis. We related physiological changes to plasma N-acetylcysteine concentrations, and compared this group with 7 patients who received placebo infusions. A variable hemodynamic response to N-acetylcysteine was observed that did not differ significantly in comparison with the placebo group, and did not correlate with plasma drug concentrations. The most significant relationship observed between DO 2 and VO 2 in any patient predicted a 13-mL • min ؊1 • m ؊2 increase in VO 2 when DO 2 increased by 100 mL • min ؊1 • m ؊2 ; in 8 patients, VO 2 was independent of DO 2 over the range observed. In the group that received N-acetylcysteine, a small (mean 6 [SD 6] mL • min ؊1 • m ؊2 ) increase in VO 2 occurred in comparison with baseline after 1 hour of infusion (P F .01), but changes were not significantly different from the placebo group and were not sustained. N-Acetylcysteine infusion did not increase oxygen extraction or result in an improvement in whole-blood lactate levels or base excess during the study period. We conclude that N-acetylcysteine infusion does not result in clinically relevant improvements in global VO 2 , or in clinical markers of tissue hypoxia in patients with severe fulminant hepatic failure. (HEPATOLOGY 1998;27:1332-1340.) Abbreviations: OER, oxygen extraction ratio; VO 2 , oxygen consumption; DO 2 , oxygen delivery; FIO 2 , fraction of inspired oxygen; RQ, respiratory quotient; SVR, systemic vascular resistance; AUC, area under the curve; ARDS, acute respiratory distress syndrome.

From the Department of Anaesthetics and the Intensive Care Unit, and the Scottish Liver Transplant Unit,