A Retrospective Study on the Clinical Outcomes of Patients With Acute Respiratory Failure Treated With Adjunctive Nebulized Tobramycin for Pneumonia

Abstract

Background. Acute respiratory failure secondary to pneumonia is a serious life threatening illness with a significant rate of morbidity and mortality. Nebulized tobramycin is often prescribed in the hospital setting by many clinicians without a definitive clinical indication and its use remains controversial. Methods. A retrospective chart review was performed identifying patients who presented to Stony Brook University Hospital from February 2013 to February 2016 using ICD-9 and ICD-10 codes for pneumonia associated with procedure codes for intubation. Patients were included if they were admitted for acute respiratory failure secondary to pneumonia with evidence of infiltrate on radiography. Patients were excluded if they were immunocompromised, had cystic fibrosis, had prior tracheostomy tube or had an unclear diagnosis. We then evaluated for clinical outcomes including 30-day mortality, number of ICU days, hospital stay and whether the patient required tracheostomy. They were risk stratified according to the APACHE II score and Pneumonia Severity Index (PSI). Results. A total of 49 patients met both inclusion and exclusion criteria; 28 patients received treatment with IV antibiotics only and 21 patients received both IV antibiotics supplemented with nebulized tobramycin. There was no statistical difference between APACHE II scores (p = 0.8) or PSI scores (p = 0.7). Patients in the tobramycin group were slightly younger (median 70 versus 73 years old). There was no statistical difference in mortality (p = 0.6). Patients in the tobramycin group had longer ICU stays (median: 15 versus 8 days), longer hospital stays (24 versus 15.5 days), and higher risk of receiving a tracheostomy 7 versus 1 (OR = 13.5, p = 0.02). Patients were started on tobramycin a median of 4 days post-intubation with the range from 3 days prior to 19 days after intubation. Five patients had tobramycin started late, at least 10 days from date of intubation, 4 of whom required a tracheostomy. Conclusion. There was a significant trend towards worse outcomes in patients receiving nebulized tobramycin compared to the IV only group, even after excluding those who had received nebulized tobramycin late (>10 days). This retrospective study is limited by the possibility of selection bias and lack of randomization despite no statistical difference between the APACHE II and PSI scores.