PURPOSE: Acute hypoxemia, whether in the setting of acute lung injury or right ventricular failure, remains a difficult entity to treat in the critically ill population. Recruitment maneuvers, inhaled nitric oxide (iNO), varying degrees of PEEP and alternative modes of mechanical ventilation such as airway pressure release ventilation or bilevel can all effect an improvement in oxygenation, transient or otherwise. However, none of these strategies have conclusively been shown to improve survival. In fact, iNO has been widely accepted as improving oxygenation but not mortality, and possibly worsening renal function. As current literature does not support the use of iNO for hypoxic respiratory failure, it was removed from our hospital formulary and replaced with inhaled epoprostenol. The physiologic rationale behind its usage is increasing pulmonary perfusion to relatively better-ventilated areas of the lung by selective vasodilatation. The hypothesis of our study was that inhaled epoprostenol would improve oxygenation and renal function in ICU patients.
METHODS: After IRB approval, we retrospectively reviewed the registry of patients who received inhaled epoprostenol in our thousand-bed tertiary care University hospital between 2008-2010. Inclusion criteria were a PaO2/FiO2 <300 prior to receiving the drug and age between 18 and 98 years. Exclusion criteria were <30 mins administration of the drug, PaO2/FiO2 >300 or age <18 or >98 years. The primary endpoints were improvement in PaO2/FiO2 ratios and improvement in post-drug 24 hr urine output.
RESULTS: A total of n=79 patients met inclusion criteria, of which there were 41.7% females (n=33) and 58.2% males (n=46), in medical, surgical and neurosurgical ICUs. 56.9% (n=45) demonstrated an improvement in PaO2/FiO2 ratios over 24 hours. 44.3% (n=35) demonstrated an improvement in 24 hr urine output after inhaled epoprostenol use. 74.6% (n=59) of patients died, out of which 24% (n=19) died within 24 hours of receiving the drug.
CONCLUSIONS: There was an expected improvement in oxygenation in more than half of the study group. The improvement in renal function in 44.3% of our patients suggests that inhaled epoprostenol may also contribute to overall improvement in hemodynamics.
CLINICAL IMPLICATIONS: Inhaled epoprostenol is a relatively better and less expensive salvage therapy for hypoxemia, as compared to inhaled nitric oxide, especially given a possible beneficial effect on renal function.
DISCLOSURE: The following authors have nothing to disclose: Misha Peter, Brian Jaffe, Christopher Gilbert, Michael Baram
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