Assessing Impaired Oxygenation through Evaluating Cough Frequency and Duration at Extubation in the Post-anesthesia Phase

Abstract

Background: Atelectasis is one of the most common postoperative respiratory complications following general anesthesia. It occurs mainly in 85% to 90% of patients who undergo general anesthesia. Postoperative atelectasis occurs due to diaphragmatic dysfunction, impaired surfactant activity, coughing at the end of anesthesia, and disturbance in (A-a) GO₂ (alveolar-arterial oxygen partial pressure gradient). The aim of this study was to evaluate the effect and duration of coughing on impaired oxygenation and atelectasis after emergence from general anesthesia under mechanical ventilation in post-anesthetic care unit.
Methods: In this prospective study, 97 patients undergoing general anesthesia and mechanical ventilation were enrolled. Quantitative and qualitative demographic data were collected through questionnaires. Arterial blood samples were taken 30 minutes before the end of the surgery and one hour after the completion of operation to measure the alveolar -arterial gradient. Data analysis was performed using SPSS-16 software, t-test and qui square test. P value <0.05 was considered statistically significant.
Results: The number of coughs before extubation or after extubation and increased duration of coughing could result in significantly increased arterial alveolar gradient.
Conclusion: Increased frequency of coughing during emergence from anesthesia and extubation results in increased Arterial - alveolar oxygen partial pressure gradient (A-a) GO₂ and also the prevalence of atelectasis in post-anesthesia care unit.