Investigation of the optimal method of oxygen administration with simultaneous use of a surgical mask: a randomized control study.

PURPOSE: From the perspective of infection prevention during the Coronavirus disease 2019 (COVID-19) pandemic, a recommendation was made to use surgical masks after extubation in patients in the operating room. For compliance with this recommendation, anesthesiologists need to administer oxygen to the patient with an oxygen mask over the surgical mask. However, no studies have investigated whether this method allows good maintenance of oxygenation in patients. This study aimed to investigate which method of oxygen administration lends itself best to use with a surgical mask in terms of oxygenation. METHOD: We administered oxygen to the study subjects using all the following three methods in random order: an oxygen mask over or under a surgical mask and a nasal cannula under the surgical mask. Oxygenation was assessed using the oxygen reserve index (ORi) and end-tidal oxygen concentration (EtO2). RESULT: This study included 24 healthy volunteers. ORi values with administration of oxygen were higher in the order of a nasal cannula under the surgical mask, an oxygen mask under the surgical mask, and an oxygen mask over the surgical mask, with median values of 0.50, 0.48, and 0.43, respectively, and statistically significant differences between all groups (P < 0.001). EtO2 values were in the same order as ORi, with median values of 33.0%, 31.0%, and 25%, respectively, and statistically significant differences between all groups (P < 0.001). CONCLUSION: Wearing a surgical mask over the nasal cannula during oxygen administration is beneficial for oxygenation and might help prevent aerosol dispersal.

A novel prediction equation of resting energy expenditure for Japanese septic patients.

Estimating nutrient consumption and administering appropriate nutritional therapy is essential for improving clinical outcomes in critically ill patients. Various equations, such as the Harris-Benedict equation, have been developed to estimate the required calories. Previous equations, however, targeted Westerners, whose physical characteristics are likely different from those of Asians. Hence, it is unclear whether these equations can be used for Asian patients. This study focused specifically on sepsis patients admitted to a single Japanese ICU, and aimed to develop novel equations to estimate their total energy expenditure. A total of 95 sepsis patients were included in this study. We measured resting energy expenditure (REE) by using indirect calorimetry, and created equations to calculate basal metabolic rate (BMR) using height, weight and age as variables. REE was predicted by multiplying BMR by the novel equation with the stress factor of 1.4. The prediction error of our novel equations were smaller than those of other conventional equations. We further confirmed the accuracy of our equations and that they were unaffected by patient age and disease severity by using data obtained from another patient group. The current study suggested that these equations might allow accurate estimation of the total energy expenditure and proper management of nutritional therapy in Asian sepsis patients.