Prehospital respiratory interventions during six waves of COVID-19: results from Israel's Emergency Medical Services system.

Abstract

Background: Despite COVID-19 having been the subject of extensive scientific research, there is a paucity of studies on the respiratory management needs of patients in the pre-hospital setting. This retrospective cohort study utilizes data from Magen David Adom (MDA), Israel's Emergency Medical Services (EMS) to investigate how prehospital respiratory management needs changed throughout the first six waves of the COVID-19 pandemic in Israel.

Methods: All EMS responses due to respiratory complaints, from March 21, 2020, to July 31, 2022, were included. Odds ratios (ORs) for each wave were calculated for each intervention with the previous wave as reference. Wave 1 (W1) was compared to a pre-pandemic period.

Results: The study included 141,027 responses. Throughout the pandemic, no endotracheal intubations were performed. The use of mask-based 90% FiO₂ decreased from the pre-COVID-19 period to W1 (OR 0.61, p < 0.0001), increased during waves 2-3 (OR 1.24, p < 0.0001 [W2]; OR 1.11, p < 0.0001 [W3]), and plateaued throughout W5 and W6 (OR 0.99, p = 0.71 [W5]; OR 0.01, p = 0.8 [W6]). The use of nasal cannula increased throughout the six waves (OR 1.2 [W1]; OR 1.48 [W2]; 1.39 [W3]; OR 1.45 [W4]; 1.11 [W5]; 1.24 [W6], p < 0.05). The use of nebulized bronchodilators decreased from the pre-pandemic period to W1 (OR 0.41, p < 0.0001). From W3 to W6, the use increased significantly for each wave (OR 1.43 [W4]; OR 1.12 [W5]; 1.31 [W6], p < 0.05).

Conclusions: MDA advised staff not to perform endotracheal intubations during the pandemic due to concerns of transmission through aerosol. Similarly, the initial drops in high-concentration O2 and nebulized bronchodilators may be due to concerns with its aerosolizing potential. The gradual replacement of high-concentration prehospital oxygen by mask with nasal cannulas over the pandemic waves may be due to the decreased pathogenicity of the new strains and expanded vaccination coverage. The increased use of nebulized bronchodilators seen during the latter waves may be due to the re-emergence of non-covid pathogens with greater bronchoconstrictive effect as social restrictions were eased. Further, as vaccine coverage expanded among providers over time, these may have been more comfortable administering bronchodilators.