Comparative analysis of methemoglobin, oxygen saturation and hematological parameters in smokers and non-smokers: an observational analytical cross-sectional study

Abstract

Introduction: The formation of methemoglobin (MetHb)occurs through the oxidation of iron in hemoglobin, impairingits capacity for oxygen association and deoxygenation.On exposure to oxidizing agents, such as those present incigarettes, this process may be more frequent, causing anincrease in serum MetHb. Objectives: To evaluate and comparemethemoglobin, oxygen saturation and hematologicalparameters between smokers and non-smokers. Materials andmethods: Observational case-control study with participantsclassified as smokers and non-smokers, in equal number andgender. Smokers classified as moderate to very high dependencedegree by the Fagerström tolerance questionnairewere included. In all subjects, oxygen saturation was assessedusing portable pulse oximetry, methemoglobin levels byspectrophotometric method and hematological parametersby an automated analyzer. Parametric (Student’s T-test) andnon-parametric (Mann-Whitney U) tests were performed forcomparison of mean values between groups. Results: Therewere no changes in methemoglobin rates and hematologicalparameters, both in relation to clinical reference valuesand in the statistical difference between groups. The oxygensaturation values were significantly higher in the smokinggroup, 96.4% versus 94.8% (p = 0.04). Conclusions: Despitethe potential deleterious effects of cigarettes, in this study itwas found that smoking was not a determinant of changes inmethemoglobin rates and hematological parameters, whencompared with non-smokers. Further studies are suggestedwith a robust sampling population, complementary analysisof hematological and physiological factors and verificationof comorbidities, in order to elucidate a greater relationshipbetween the presented parameters.