Differences between the first and the second wave of critically ill COVID-19 patients admitted to the intensive care units

BACKGROUND: To compare the demographic characteristics and prognosis of patients admitted to the intensive care unit (ICU) for coronavirus disease 2019 (COVID-19) pneumonia during the first wave (March−July) versus those admitted during the second wave (August−December). METHODS: Prospective, observational, descriptive cohort-study including patients admitted to the ICU for COVID-19 pneumonia during the first wave (March−July 2020) or the second wave (August−December). The demographic characteristics, comorbidities, treatments, complications, and mortality in both pandemic waves were studied. RESULTS: A total of 72 patients were included: Twenty-six admitted during the first wave and 46 during the second wave. Men were predominant in both waves: 61.5% versus 73.9%. The most frequently associated comorbidities in both periods were: arterial hypertension 65.4% versus 65.2%, diabetes mellitus 46.2% versus 34.8% and overweight, measured as (body mass index), 29.13 ± 3.38 versus 28.98 ± 4.25. More patients received noninvasive mechanical ventilation prior to invasive ventilation during the second wave (P < 0.01); the incidence of atelectasis and bronchial obstruction were lower during the second wave (P < 0.01 and P = 0.055 respectively); no further differences were observed in the occurrence of other complications. CONCLUSIONS: No significant differences were observed between the first and the second wave in the demographic characteristics or comorbidities of admitted patients. Blood hypertension, diabetes and overweight were remarkable risk factors. Improving our knowledge of the complications, these patients tend to develop was essential to reduce some of them, such as endotracheal tube obstruction or atelectasis, and to promote the use of noninvasive ventilation therapies.