RESUMO
Background: N95 filtering facepiece respirators (FFR) are used by health care workers for prevention of airborne infection, and its use has increased manifolds during COVID-19 pandemic. Prolonged use may result in carbon dioxide (CO2) accumulation, affect hemodynamics, and blood gas values. Although arterial blood gas values accurately measure the blood CO2 levels, venous blood gas values also show acceptable correlation. Aim: To evaluate the physiological impact of N95 FFRs on health care workers, including hemodynamic changes and venous blood levels of CO2 during a period of 6 h. Settings and Design: Prospective observational study in a tertiary care hospital. Methods: The study was conducted on 30 health care workers who performed routine duties while wearing N95 FFR. Venous blood gas values (CO2, pH, and bicarbonate) and vitals (respiratory rate, heart rate, blood pressure, and saturation) were noted at baseline, 2 (T2), and 6 h (T6) after wearing the mask. Discomfort level was also measured on a Visual Analogue Scale (VAS) of 1-10. Statistical Analysis: Repeated measures analysis was done using repeated measures ANOVA or Friedman's test. Group comparisons for continuously distributed data were made using independent sample "t" test or Wilcoxon test. Results and Conclusion: Hemodynamic and blood gas values did not change over time. The VAS for discomfort because of respirator use was 1.33 (1.42) at T2 and 2.77 (1.91) at T6. This was a significant increase in discomfort over time (P = 0.001). About 80% of participants experienced discomfort during this period. N95 FFR did not lead to significant alteration in hemodynamics or change in blood gas values after 6 h of continuous usage. However, discomfort significantly increased over time.
RESUMO
Background and Aims: A definitive cutoff of inferior venacava (IVC) diameter in expiration (dIVCmax) and inferior vena cava collapsibility index (IVCCI) for predicting general anaesthesia associated hypotension (GAAH) is not yet determined. Primary objective of this study was to determine the correlation of dIVCmax and IVCCI, with GAAH. Other objectives were to determine the correlation of these IVC parameters with preoperative fasting duration, temperature and humidity. The correlation of dIVCmax with patient demography was also studied. Methods: A total of 110 adult patients undergoing elective surgery under general anaesthesia were included in the study. IVC ultrasonography was done in the preoperative room, 20 to 30 minutes before shifting the patient to the operating room. Hypotension at (hypo@) 2 minutes and 10 minutes after administering vecuronium was recorded. Results: Hundred and seven patients were analysed. A significant positive correlation was present between patient height and dIVCmax (r = 0.25, P = 0.009). Area under receiver operating characteristics curve was 0.595 (95% confidence interval (CI) 0.485-0.705) and 0.568 (95% CI 0.458-0.679) for dIVCmax and IVCCI for predicting hypo@2 min, with a diagnostic accuracy of 54% and 53%, respectively. dIVCmax ≤1.14 cm had a sensitivity of 31% and specificity of 87% in predicting GAAH. IVCCI ≥63.3% could predict GAAH with 31% sensitivity and 84% specificity. No significant correlation was found between preoperative IVC parameters and preoperative fasting or environmental factors. Conclusion: Both dIVCmax and IVCCI have poor diagnostic accuracy, with good specificity and low sensitivity in predicting GAAH. A steady formula for calculating baseline IVC diameter adjusted for patient demography is needed.