Prolonged time on mechanical ventilation is associated with multiple consequences for both the patient and medical facility. Based on anecdotal evidence that sustained elevation of beta-natriuretic protein (BNP) during a patient's stay in a long-term acute care hospital (LTACH) was associated with failure to wean from prolonged mechanical ventilation, we investigated if there is an association between a decrease in BNP levels during one's stay and successful weaning from prolonged mechanical ventilation. We performed a retrospective study of 66 patient records revealing no correlation between lowering BNP levels and probability of liberating a patient from prolonged mechanical ventilation in an LTACH environment where the probability of liberation from mechanical ventilation is high (> 85%). BNP measurements by itself does not appear to be a helpful tool in the likelihood of liberation from mechanical ventilation AUC = 0.61 (CI: 0.48-0.72). In an LTACH setting with high success rates of liberation from mechanical ventilation, it does not appear to be necessary to trend BNP measurements in attempts to liberate patients from prolonged mechanical ventilation.