Thermal imaging and velocity measurements of the exhaled airflow in total laryngectomized patients during COVID-19 pandemic.

Abstract

In patients after total laryngectomies, the trachea and the lung can be easily infected by SARS-CoV-2 because the respiration happens through the tracheostoma. The aim of our study was to examine whether patients with LaryTube™ can distribute aerosols to a greater extent than without LaryTube™, and to observe whether the surface of different protective instruments can be examined using the thermal camera in total laryngectomees. An important objective was also to confirm the assumption that the use of HME (heat and moisture exchanger) alone does not provide protection during COVID-19 pandemic. Finally, during our tests, we tried to get an answer to our assumption that the sample taken from the inner surface of the HME can be tested for SARS-CoV-2. A total of 23 patients who underwent total laryngectomies were analyzed by velocity measurements and thermal imaging with and without HMEs and laryngeal tubes, using different types of PPEs. COVID-19 PCR testing was performed on patient tracheas and the inner surfaces of the HMEs. Male patients with laryngeal tubes without HMEs demonstrated an increase in exhaled airflow velocity of more than 43% compared to male patients without laryngeal tubes; in female patients, the same value was more than 39%. Thermal imaging results confirmed that the lowest surface temperature was measured on FFP2 masks. The sent samples can be tested for SARS-CoV-2 using PCR, the presence of the virus was not detected. Laryngectomized patients without laryngeal tubes pose a lower risk for spreading viral aerosols due to the reduced velocity of the exhaled airflow caused by the absence of the tube as the narrowing factor. Patients with laryngeal tubes who undergo total laryngectomies during the COVID-19 pandemic should use HMEs with viral filter, if possible, also changing the laryngeal tubes to dermal adhesives for fitting their HMEs seems to be the best option. The surface of the used protective equipment can also be examined with thermal camera in the case of total laryngectomees. COVID-19 PCR testing of the tracheal secretion from the inner HME surfaces should become a routine in clinical practice if deemed necessary. Orv Hetil. 2023; 164(34): 1327-1336.