Prevention of gram negative bacillary pneumonia using polymyxin aerosol as prophylaxis. II. Effect on the incidence of pneumonia in seriously ill patients

Abstract

All 744 patients admitted to a Respiratory Surgical Intensive Care Unit (RSICU) were included in a prospective study of the effects of a polymyxin (2.5 mg/kg body wt/day in 6 divided doses) or a placebo aerosol sprayed into the posterior pharnyx and tracheal tube (if present), during 11 alternating 2 mth treatment cycles. Te incidence of upper airway colonization in the RSICU with Pseudomonas aeruginosa was 1.6% during the polymyxin treatment cycles (total 374 patients) and 9.7% during the placebo cycles (370 patients) (x2 = 23.2, P < 0.01). 3 patients in the RSICU acquired Pseudomonas pneumonia, as defined by independent 'blinded' assessors, during the polymyxin cycles while 17 acquired a Pseudomonas pneumonia during the placebo cycles (x2 = 10.2, P < 0.01). The overall mortality was similar in both placebo and polymyxintreated groups (12.2 vs. 12.0%). Systemic antibiotic usage was similar in the different cycles; 49% of patients in the placebo and 53% in the polymyxin treated groups received systemic antibiotics while in the RSICU.