Antibiotherapy and Mortality Rate in Ventilator-Associated Pneumonia and Tracheobronchitis due to Acinetobacter Baumannii

Abstract

INTRODUCTION[|]Ventilator-associated pneumonia (VAP) due to Acinetobacter baumannii (A. baumannii) has a high mortality rate in the intensive care unit (ICU). The guidelines recommend empirical antimicrobial therapy in cases of VAP; however, similar treatment is not recommended in cases of ventilator-associated tracheobronchitis (VAT) with a culture result of A. baumannii. The aim of this study was to evaluate the difference in the ICU and long-term mortality of patients with A. baumannii VAP and VAT who were treated with antibiotherapy.[¤]METHODS[|]This was a retrospective cohort study. Patients who were intubated in the respiratory ICU due to acute respiratory failure (ARF) and developed A. baumannii-associated VAP or VAT between January 2015 and January 2016 were included in this study. Demographic features, comorbidities, cause of ARF, arterial blood gas values, oxygenation level, chest X-ray findings, ICU severity scores (Sequential Organ Failure Assessment [SOFA] score, Charlson Comorbidity Index score, Acute Physiology and Chronic Health Evaluation II score), culture antibiotic susceptibility results, antibiotic regimen, length of ICU stay, and mortality details were recorded. Long-term mortality (1-, 2-, 3-, 12-month) details were obtained from national death records. The Kaplan-Meier method was used for long-term survival analysis.[¤]RESULTS[|]Among 503 consecutive patients intubated between January 2015 and January 2016, 78 (15.5%) who had A. baumannii-associated VAT and VAP were included. Of the 78 patients, 21 (35%) were cases of VAP and 50 (65%) were cases of VAT. Diagnoses of the 78 patients were 62% chronic obstructive pulmonary disease, 15% pneumonia, 10% acute cardiogenic pulmonary edema, 9% lung cancer, and 4% kyphoscoliosis. Among the VAP patients, 21 (75%) were male and 7 (25%) were female, while among the VAT patients, 38 (76%) were male and 12 (24%) were female. There was no statically significant difference between the VAP and VAT patients according to age, gender, comorbidities, the presence of acute respiratory distress syndrome or septic shock, Charlson and SOFA scores, or length of hospital and ICU stay. The median (quartile ratio) duration of mechanical ventilator use was 15 days (7–22 days) for VAP patients and 12 days (6–14 days) for VAT patients (p=0.649). The ICU mortality rate was 68% among VAP patients and 40% among VAT patients (p<0.018). The length of the median follow-up after discharge (25%-75%) for VAT patients (n=30) and VAP (n=9) patients was 407 days (34–574 days) and 112 days (34–524 days), respectively (p=0.852). Kaplan-Meier survival analysis was similar for both VAP and VAT patients (p=0. 57). The 1-, 2-, 3-, and 12-month mortality in VAP and VAT patients was 11.1% and 16.6% (p=0.69), 44.4%, and 26.7% (p=0.31), 44.4% and 33.3% (p=0.54), and 66.7% and 46.7%, respectively (p=0.29).[¤]DISCUSSION AND CONCLUSION[|]Despite antimicrobial treatment for A. baumannii, 2 of every 3 VAP patients and 2 of every 5 VAT patients died. Nonetheless, though antibiotic treatment is not currently recommended for VAT, these results suggest that mortality might be higher in A. baumannii-associated VAT without antimicrobial therapy. Clinical findings and infection markers of patients with VAT due to A. baumannii should be evaluated together and a decision made for patient-specific treatment.[¤]

Keywords

• drug resistance
• mortality; ventilator-associated pneumonia.