Haemodynamics and Arterial Blood Gases in Smokers versus Non Smokers during General Anaesthesia for Abdominal Surgeries: A Prospective Observational Study

Introduction: Tobacco smoking is a worldwide accepted health hazard and its effect on cardiopulmonary system is a well known fact. In a long run, it results in to gross derangements in haemodynamics and Arterial Blood Gases (ABG) which can lead to further complications during general anaesthesia. Aim: To evaluate the effect of smoking on cardiopulmonary system and also to compare its effects on haemodynamics and ABG during general anaesthesia for abdominal surgeries in smokers and non smokers. Materials and Methods: This prospective observational analytical study was conducted in the Department of Anaesthesiology, Mahatma Gandhi Memorial Medical Colledge, Indore, Madhya Pradesh, India, from May 2020 to April 2021. The study included 74 male patients of American Society of Anaesthesiologist (ASA) grade I and II, aged 20-70 years, undergoing elective abdominal surgeries. The patients were divided into two groups, smokers and non smokers, depending on their smoking status. Haemodynamic monitoring was done from preinduction time till 48 hours after extubation and ABG analysis was also done before induction and two hours after extubation in both the groups. T-test and Mann-whitney test were applied according to the requirement. A p-value <0.05 was taken as statistically significant. The statistical software Statistical Package for Social Sciences (SPSS) version 20.0 and Medcalc 19.5 were used for the analysis. Results: Significant increase in Heart Rate (HR) and Mean Arterial Pressure (MAP) was observed in smokers as compared to non smokers at all time intervals (p-value <0.001). End-tidal carbon dioxide concentration (EtCO2) values were found to be significantly higher in smokers (37.77±2.63 mmHg) than non smokers (32.99±2.83 mmHg) (p-value <0.001). Regarding arterial blood gas analysis significant difference was observed in preoperative and postoperative arterial carbon dioxide concentration (PaCO2) (p-value <0.0001) and pH levels (p-value <0.0001) in both the groups. A significant difference was also seen in preoperative and postoperative PaCO2 levels of the smokers (p-value=0.0004) with a corresponding change in their pH levels also (p-value=0.0012). Peak Expiratory Flow Rate (PEFR) was lower in smokers in comparison to non smokers (p-value