The use of invasive mechanical ventilation in hospitalized covid-19 patients

Introduction: Increased mortality due to COVID-19 in the intensive care unit (ICU) raised questions about the best way and time to use invasive mechanical ventilation (IMV). The purpose of this study is to analyze effectiveness of IMV in COVID-19 patients. Methods: We performed a retrospective analysis of adult patients admitted to our hospital with COVID-19 infection from May 2020 to December 2021. We reviewed the need of IMV in patients admitted to the ICU with APACHE II scores higher than 12.5. Outcomes from the IMV-receiving patients were compared to outcomes from patients on non-invasive mechanical ventilation (NIMV). The second analysis of IMV aimed to determine the best initiation time for IMV. Patients were divided into Group1: early intubation (IMV within the first 24hrs of admission) and Group2: late intubation (IMV later than 24hrs after admission). Primary outcomes included mortality and length of stay (LOS) in the ICU. Descriptive statistics, Mann-Whitney-U and Chi-square methods were used. Results: For the first part of the analysis, 82 patients were included. They were divided into 2 groups (IMV and NIMV) of 41 patients each. Median age in IMV group was 67 [51.5-75.5] vs 64 [47.5-73.5]. 21 (51.2%) patients died in the IMV group vs 22 (53.7%) X2(1, N=82)=0.049, p=0.5. Median LOS in the IMV group was 10 [6-16] days vs 11 [5-19.5] days U(NIMV group=41, NNIMV group=41)=819, z=-0.2, p=0.84. For the second analysis, 68 patients were included. They were divided into 2 groups (Group1 and 2) of 34 patients each. Median age in group1 was 53.5 [25-90] vs 53.5 [37.75-65.25]. 19 (55.9%) patients in group1 were male vs. 26 (76.5%). The median APACHE II, SOFA and ICHIKADO scores on admission in group1 were 8 [6-10.5], 1.5 [1-2], 120 [110-165] points respectively vs 9.5 [6-16.5], 2 [1-4], 150 [132.5-200] points. 3 (8.8%) patients died in group1 vs 11 (32.4%) X2(1, N=68)=5.76,p=0.033. Median LOS in group1 was 4.5 [3-8.5] days vs 6 [3.75-10.5] days U(NGroup1=34, NGroup2=34)=450, z=-1.59, p=0.113. Conclusions: In COVID-19 patients admitted to the ICU with APACHE II score higher than 12.5, mortality and LOS were not significantly different in patients that received IMV vs those that received NIMV. Early intubation correlated with improved mortality, but not with length of ICU stay.