Indoor CO2 and Thermal Conditions in Twenty Scottish Primary School Classrooms with Different Ventilation Systems during the COVID-19 Pandemic

Healthy indoor environments influence the comfort, health and wellbeing of the occupants. Monitoring the indoor temperature, relative humidity and CO2 levels in primary schools during the COVID-19 pandemic was mandated by a local authority in Scotland. The aim was to investigate the comfort and safety of the teachers and their pupils. This paper presents the measurements of indoor climate in 20 classrooms in four different primary schools in Scotland. The schools were of different architypes. The classrooms were of different sizes, orientations and occupancy, and had different ventilation systems. Ventilation was achieved either by manually opening the windows, or by a mechanical ventilation system. Indoor air temperature, relative humidity and carbon dioxide (CO2) concentrations were continuously monitored for one week during the heating season 2020/21. Occupancy and opening of the windows were logged in by the teachers. The ventilation rates in the classrooms were estimated by measuring the CO2 concentrations. On the 20 classrooms of the study, data of 19 were analysed. The results show that four of the five mechanically ventilated classrooms performed better than natural ventilation, which indicates that opening the windows depended on the customs and habits. Classrooms in naturally ventilated Victorian buildings have the worst average ventilation rate (4.38 L/s per person) compared to the other classrooms (5.8 L/s per person for the more recent naturally ventilated ones, and 6.08 L/s per person for the mechanically ventilated ones). The results of this preliminary study will be used as the basis to find ways to ensure adequate ventilation in natural ventilated classrooms.

The application of a surgical face mask over different oxygen delivery devices; a crossover study of measured end-tidal oxygen concentrations.

BACKGROUND: The application of a surgical face mask over oxygen delivery devices is now a widespread recommendation in the setting of the Coronavirus disease pandemic. This addition is designed to reduce droplet spread, but this also changes the nature of these devices, and may alter the amount of oxygen delivered to a patient. This research investigated how placing a surgical face mask over both a simple plastic mask ("Hudson mask") and nasal cannula altered the concentration of available oxygen measured at the nares. METHODS: We measured the inspired and end-tidal oxygen concentrations of five healthy non-smoking volunteers. Oxygen was delivered via nasal cannula and also a simple plastic face mask, at flow rates of 2, 4, 6 and 8 l per minute, with and without an overlying surgical face mask. RESULTS: Adding a surgical mask over nasal cannula caused an appreciable rise in the end-tidal oxygen concentrations at all the measured oxygen flow rates 2, 4, 6, 8 L/minute. With the Hudson mask, there was a rise in oxygen concentration at 4 and 6 L/minute. For example, at a flow rate of 4 l/min via nasal cannula, available oxygen concentration increased from 24 to 36%, and via the Hudson mask the concentration rose from 27 to 38%. CONCLUSIONS: The addition of a surgical face mask over both nasal cannula and a Hudson mask resulted in an increased available oxygen concentration. This may be valuable where more advanced oxygen devices are not available, or alternatively providing adequate supplemental oxygen at lower flow rates and thus making critical savings in oxygen usage.

Airway Management in the Operating Room and Interventional Suites in Known or Suspected COVID-19 Adult Patients: A Practical Review.

Current evidence suggests that coronavirus disease 2019 (COVID-19) spread occurs via respiratory droplets (particles >5 µm) and possibly through aerosol. The rate of transmission remains high during airway management. This was evident during the 2003 severe acute respiratory syndrome epidemic where those who were involved in tracheal intubation had a higher risk of infection than those who were not involved (odds ratio 6.6). We describe specific airway management principles for patients with known or suspected COVID-19 disease for an array of critical care and procedural settings. We conducted a thorough search of the available literature of airway management of COVID-19 across a variety of international settings. In addition, we have analyzed various medical professional body recommendations for common procedural practices such as interventional cardiology, gastroenterology, and pulmonology. A systematic process that aims to protect the operators involved via appropriate personal protective equipment, avoidance of unnecessary patient contact and minimalization of periprocedural aerosol generation are key components to successful airway management. For operating room cases requiring general anesthesia or complex interventional procedures, tracheal intubation should be the preferred option. For interventional procedures, when tracheal intubation is not indicated, cautious conscious sedation appears to be a reasonable approach. Awake intubation should be avoided unless it is absolutely necessary. Extubation is a high-risk procedure for aerosol and droplet spread and needs thorough planning and preparation. As updates and modifications in the management of COVID-19 are still evolving, local guidelines, appraised at regular intervals, are vital in optimizing clinical management.