PERIOPERATIVE CHANGES IN CARBOXYHEMOGLOBIN AND METHEMOGLOBIN

Abstract

Introduction: The inhalation of tobacco smoke can substantially raise the level of carboxyhemoglobin in the blood. The carboxyhemoglobin level can thus identify those people at risk from any of the diseases associated with the inhalation of tobacco smoke even if carbon monoxide is not directly implicated in the pathogenesis of those diseases. Aim: The aim of the study was to investigate the range of carboxyhemoglobin and methemoglobin in the smoking and non-smoking patients and the effect of pre-oxygenation with 100% of oxygen on their level. Furthermore, we evaluated the perioperative changes in carboxyhemoglobin and methemoglobin during surgery. Material and methods: The study included 20 patients scheduled for urological surgery under general endotracheal anesthesia, aged 18–60 years without any history of respiratory disease, divided into two groups. In the study group (n=10) were included patients who were smoking cigarettes or tobacco pipe, while the control group (n=10) included nonsmokers. In groups carboxyhemoglobin and methemoglobin levels were determinate pre-operatively (T0 ), after pre-oxygenation with 100% oxygen before induction in anesthesia (T1 ) and postoperatively (T2 ). The influence of smoking was disregarded in the analysis, because smoking was shown to increase exogenous and endogenous carbon monoxyde, respectively. Results: Postoperative carboxyhemoglobin levels were lower than the preoperative, (from 2.2 ± 1.32SD vs. 2.02 ± 0.65SD) for smoking group and (from 0.56 ± 0.29SD vs. 0.44 ± 0.21SD) for nonsmoking group. Postoperative values of carboxyhemoglobin (2.02 ± 0.656 vs 0.44 ± 0.211, p=0.000) were higher in the smoking group compared to nonsmoking group. On the other hand Perioperative changes in carboxyhemoglobin and methhemoglobin values of methemoglobin postoperatively (0.25 ± 0.108 vs. 0.29 ± 0.070, p=0.33) were lower in smoking compared with nonsmoking group, but no significant difference was found. In both groups, methemoglobin increased after pre-oxygenation and postoperative, and there was no effect of smoking on the changes in methemoglobin. Conclusion: Changes in carboxyhemoglobin and methemoglobin concentrations in arterial blood occur during urological surgery, although these amplitudes are small when compared with carbon monoxide intoxication and methemoglobinemia. It is likely that organ perfusion and functions are affected by these monoxide gas mediators during urological surgery