Clinical outcomes of patients requiring ventilatory support in Brazilian intensive care units: a multicenter, prospective, cohort study

Abstract

Introduction: Contemporary information on mechanical ventilation (MV) use in emerging countries is limited. Moreover, most epidemiological studies on ventilatory support were carried out before significant developments, such as lung protective ventilation or broader application of non-invasive ventilation (NIV). We aimed to evaluate the clinical characteristics, outcomes and risk factors for hospital mortality and failure of NIV in patients requiring ventilatory support in Brazilian intensive care units (ICU).

Methods: In a multicenter, prospective, cohort study, a total of 773 adult patients admitted to 45 ICUs over a two-month period requiring invasive ventilation or NIV for more than 24 hours were evaluated. Causes of ventilatory support, prior chronic health status and physiological data were assessed. Multivariate analysis was used to identifiy variables associated with hospital mortality and NIV failure.

Results: Invasive MV and NIV were used as initial ventilatory support in 622 (80%) and 151 (20%) patients. Failure with subsequent intubation occurred in 54% of NIV patients. The main reasons for ventilatory support were pneumonia (27%), neurologic disorders (19%) and non-pulmonary sepsis (12%). ICU and hospital mortality rates were 34% and 42%. Using the Berlin definition, acute respiratory distress syndrome (ARDS) was diagnosed in 31% of the patients with a hospital mortality of 52%. In the multivariate analysis, age (odds ratio (OR), 1.03; 95% confidence interval (CI), 1.01 to 1.03), comorbidities (OR, 2.30; 95% CI, 1.28 to 3.17), associated organ failures (OR, 1.12; 95% CI, 1.05 to 1.20), moderate (OR, 1.92; 95% CI, 1.10 to 3.35) to severe ARDS (OR, 2.12; 95% CI, 1.01 to 4.41), cumulative fluid balance over the first 72 h of ICU (OR, 2.44; 95% CI, 1.39 to 4.28), higher lactate (OR, 1.78; 95% CI, 1.27 to 2.50), invasive MV (OR, 2.67; 95% CI, 1.32 to 5.39) and NIV failure (OR, 3.95; 95% CI, 1.74 to 8.99) were independently associated with hospital mortality. The predictors of NIV failure were the severity of associated organ dysfunctions (OR, 1.20; 95% CI, 1.05 to 1.34), ARDS (OR, 2.31; 95% CI, 1.10 to 4.82) and positive fluid balance (OR, 2.09; 95% CI, 1.02 to 4.30).

Conclusions: Current mortality of ventilated patients in Brazil is elevated. Implementation of judicious fluid therapy and a watchful use and monitoring of NIV patients are potential targets to improve outcomes in this setting.

Trial registration: ClinicalTrials.gov NCT01268410.

Figure 1

Flowchart of the study.

Figure 2

ICU and hospital mortality rates according to ventilatory support, ARDS diagnosis and NIV failure. ARDS, acute respiratory distress syndrome; ICU, intensive care unit; MV, mechanical ventilation.

Figure 3

ICU and hospital mortality rates according to the Berlin definition of ARDS. P < 0.001 (Pearson Chi-square test) for the comparison of hospital mortality and ARDS classification. ARDS, acute respiratory distress syndrome; ICU, intensive care unit.

Figure 4

Interaction of risk factors for failure of non-invasive ventilation and hospital mortality. Fluid balance denotes cumulative fluid balance ≥ 2 L in the first 72 hours of intensive care unit stay. SOFA score denotes Sequential Organ Failure Assessment punctuation ≥ 4 (excluding respiratory component). ARDS denotes Acute Respiratory Distress Syndrome. P < 0.001 (Pearson Chi-square test) for both the comparisons of hospital mortality and non-invasive ventilation failure and risk factors interaction.