Assessment of clinical and laboratorial parameters and the usefulness of the Brain Natiuretic Peptide as a predictor for successful extubation in the ICU

Abstract

Introduction: Identification of predictors for successful extubation in an Intensive Care Unity and use of Brain Natriuretic Peptides (BNP) in predicting mechanical ventilation weaning and extubation outcome.Aims: Evaluation of the effect of variables such as patient´s age, severity score, use of sedation, use of vasoactive drugs, hydric balance, blood gas data, days under mechanical ventilation, the occurrence of adverse events and plasma BNP levels on the success of extubation.Method: A prospective cohort study of adult patients admitted to a 12- bed-general ICU, from April 1st 2016 to August 10th 2017, under mechanical ventilation for > 24 h, accompanied until discharge or death. Clinical variables were analyzed and BNP was assessed before initiation of Spontaneous Breathing Trial (SBT) and then again before extubation. Statistical Analysis: a descriptive and comparative data analysis, univariate and logistic regressionanalysis for verification of variables independently related to successful extubation (p < 0.05).Results: Study of 105 patients, mean age of 53.9 ± 19.8 years, 81% of success in extubation; the overall mortality rate of 11.4%; variables associated to successful extubation: age, APACHE II, SAPS II, days of hospitalization before ICU admittance, days under mechanical ventilation, days of stay in ICU and occurrence of nosocomial infection (p < 0.05); BNP levels were lower in patients with successful extubation although not statistically significant;multivariate analysis showed that patient’s age and days of hospitalization before ICU admittance were each independently linked to extubation failure; APACHE II score and days of hospitalization before ICU admittance were each independently associated to risk of death.Conclusion: Despite being older and with higher severity scores, patients had a higher success rate in extubation than found in similar studies. However, the mortality rate in cases of failed extubation was higher. Data obtained was in agreement to studies that suggested that patient´s age, severity score, days of hospitalization before ICU admittance, days of stay in ICU, days under MV and infection occurrence were all variables associated as much extubation failure as to risk of death. A direct association between BNP levels and successful extubation and the usefulness of assessing BNP in the conduction of WMV was not confirmed.