Current State of Ventilator Setting and Their Relationship with Mortality Rate in Patients under Mechanical Ventilation: A Cross-Sectional Study

Background: Given the importance of implementing lung protective strategies to prevent lung injury caused by ventilators and death of patients, it is necessary to monitor the current condition of hospitals and examine the relationship between the parameters set on the ventilators and patient mortality. This study conducted to determine the current state of ventilator setting and their relationship with mortality rate in patients under mechanical ventilation: a cross-sectional study. Methods: This is a cross-sectional study that was conducted between June to December 2020 in one of the hospitals affiliated to Tehran University of Medical Sciences. The initial tidal volume set on the ventilator was recorded for 304 patients under mechanical ventilation and then, their heights were measured and their tidal volumes were determined based on the standard formula. Other parameters set on the ventilator as well as systolic and diastolic blood pressures of patients were also recorded and their survival rate was investigated. The data was analyzed by SPSS software, using descriptive statistics and logistic regression model. Results: Among patients, who were under mechanical ventilation, 77.6% were hospitalized in intensive care units and the rest were hospitalized in general wards. The mean adjusted tidal volume for patients was 472.91 ± 32.13 ml. The mean peak inspiratory pressure and plateau pressure were 28.00±6.98 and 13.88±4.93 CmH2O, respectively. Also, 37.2% of patients died during the hospitalization. The results of adjusted odds ratio based on multivariate logistic regression model for predictors of mortality rate showed that the variables of patients' age [OR=1.040 (1.019-1.062)], the hospital’s general ward in comparison with the ICU [OR=11.379 (5.130-25.240)] and the peak inspiratory pressure [OR=1.072 (1.007-1.141)] had a direct and significant relationship with mortality rate (in all cases P<0.05). Meanwhile, the plateau pressure [OR=0.886 (0.808 -0.972)] had an inverse and significant relationship with mortality rate (P<0.05). Conclusion: Despite the recommendations regarding lung protective strategies, in some cases, some parameters set in the ventilator are outside the recommended levels, which can effect on patients mortality. So monitoring and controlling the implementation of lung protective strategies and paying attention to controlling pressures set on the ventilator are among measures that should be taken in medical centers in order to prevent lung injuries and maintain patient safety.