Increased carbon monoxide production in patients with cirrhosis with and without spontaneous bacterial peritonitis

Abstract Carbon monoxide, a product of the heme-oxygenase (HO) pathway, is an important endogenous vasoactive substance. Production of CO has not been assessed in human cirrhosis. The aim of this study was to assess production of CO in patients with cirrhosis with and without spontaneous bacterial peritonitis (SBP). CO concentration in the exhaled air and blood carboxyhemoglobin (COHb) levels, as estimates of total HO activity, were determined in 16 healthy subjects, 32 noninfected cirrhotic patients (20 with ascites), and 19 patients with SBP, all nonsmokers. Noninfected cirrhotic patients had a CO concentration in the exhaled air and COHb levels significantly higher compared with values of healthy subjects (2.3 ± 0.2 ppm vs. 0.7 ± 0.1 ppm and 1.0% ± 0.1% vs. 0.6% ± 0.1%, respectively; P P r = 0.71, P epathology 2003;38:452-459.)