The effect combined use of N99/FFP3 mask and surgical mask on ETCO2 levels in operating room staff

Objective: One of the most important prerequisites for human life is the continuous elimination of carbon dioxide. There is a balance between the production and excretion of CO2 in the body: its transport from the tissues through the blood, its distribution to the alveoli, and its removal by ventilation. Any disruption of these transport and elimination processes causes hypercapnia, which significantly impairs homeostasis. The aim of this study is to evaluate the effect of the combined use of N99/FFP3 mask and surgical mask on ETCO2 levels in operating room staff. Material and Methods: The study was conducted as a prospective observational study in Cukurova University Faculty of Medicine, Department of Anesthesiology. After obtaining the approval of the ethics committee and the written consent of the participants, 55 volunteer health workers between the ages of 18-60 working in the operating room of Cukurova University Medical Faculty Balcalı Hospital between 15.112021-30.12.2021 were included in the study. Capnograph (CapnostreamTM35 portable respirator monitor) and capnograph compatible ETCO2 sampling line-nasal cannula (filter line®) were used for ETCO2 measurement in the study. Demographic characteristics of the participants, current or past diseases, smoking, ETCO2, pulse, oxygen saturation, respiratory rate, IPI (Integrated Pulmonary Index) values during breathing without mask were recorded in the information form and after wearing N99/FFP3 mask and surgical mask values were followed up at the 10th -20th – 30th minutes and recorded in the study. They were in daily working conditions at the operating room. All data were analyzed by Cukurova University Biostatistics Department. IBM SPSS Statistics Version 20.0 package program was used for statistical analysis of the data. Results: The mean age of the participants included in the study was 29.3±4.5, 49.1% were male and 50.9% were female. The mean height of the participants was 171.5 ± 9.7 cm, the mean body weight was 70.4 ± 13.5 kg, and the mean body mass index was 23.8 ± 2.9 kg/m2. 34.5% of the participants included in the study had a smoking history, and 65.5% had no smoking history. 47.3% of the participants had a history of COVID-19, and 52.7% did not have a history of COVID-19. It was observed that 20% of the participants had a history of chronic disease and 80% did not have a history of chronic disease. Statistically significant changes were found in end-tidal carbon dioxide, respiratory rate, IPI score, and heart rate values over time (without mask - 10 minutes using mask - 20 minutes using mask - 30 minutes using mask). No statistically significant changes were found in the oxygen saturation values over time. No statistically significant relationship was found between body mass index, previous COVID-19 history, chronic disease history and ETCO2 increase. A statistically significant correlation was found between the history of smoking and the increase in ETCO2. It was determined that smoking status caused a 2.75-fold increase in ETCO2 (baseline – 30th minute) difference compared to non-smokers. No statistically significant correlation was found between body mass index, previous COVID-19 history, smoking, chronic disease history and decreased EPI score.Conclusion: According to the data obtained from our study, the combined use of N99/FFP3 mask and surgical mask causes a significant increase in ETCO2 values over time. We found a significant decrease in the EPI score with a significant increase in respiratory rate and heart rate over time, which are our secondary results. According to our results, we observed that being a smoker causes a 2.75-fold increase in ETCO2 difference compared to non-smokers.