Aim: This study investigated the characteristics and outcomes of critically ill medical patients who received invasive mechanical ventilation (IMV) in the intensive care unit (ICU).

Study Design: This retrospective study was conducted between January 2011 and January 2015 in a nine-bed tertiary medical ICU. Patients older than 18 years who received IMV for more than 48 hours were included. Univariate and multivariate analyses were performed to compare the patients who died and survived in the ICU and to identify the independent risk factors for mortality.

Results: During the study period, among 715 patients admitted to the ICU, 41% received IMV. A total of 296 patients were included in the study. The median Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22 [18-27]. The most common reasons for initiating IMV were pneumonia (57.1%) and sepsis (48.6%). Sepsis (50.3%) was the most fre-quent complication. Among 202 patients who underwent a weaning trial, 153 were extubated, 22 of which involved unplanned extubation. Forty-eight patients required a tracheostomy for weaning. A total of 194 patients (65.5%) died in the ICU, while 102 patients (34.5%) were discharged successfully. Independent risk factors for mortality included new-onset sepsis de-veloped under IMV (odds ratio [OR], 95% confidence interval [CI]: 18.39 [9.00-37.56), p<0.01], intubation due to sepsis (OR, 95% CI: 2.72 [1.43-5.19], p=0.02), and a high APACHE II score (OR, 95% CI: 1.11 [1.05-1.16], p<0.01).

Conclusions: Although IMV is an essential lifesaving therapy for critically ill patients, mortality was relatively high in this population. Sepsis, both as the cause of IMV and as a complication, along with elevated APACHE II scores, were the primary determinants of mortality.