Continuous control of tracheal cuff pressure and microaspiration of gastric contents: a randomized controlled study
© Nseir et al. 2011
Published: 1 March 2011
Underinflation of a tracheal cuff frequently occurs in critically ill patients, and results in microaspiration of contaminated oropharyngeal secretions and gastric contents that plays a major role in the pathogenesis of VAP. The aim of this study was to determine the impact of continuous control of cuff pressure (Pcuff ) on microaspiration of gastric contents.
Patients requiring mechanical ventilation through a PVC-cuffed tracheal tube >48 hours were eligible. Patients were randomly allocated to continuous control of Pcuff using a pneumatic device (Nosten®) (intervention group, n = 61) or routine care of Pcuff (control group, n = 61). Target Pcuff was 25 cmH2O in the two groups. The primary outcome was microaspiration of gastric contents as defined by the presence of pepsin at a significant level (> 200 ng/ml) in tracheal secretions. Secondary outcomes included incidence of microbiologically confirmed VAP (tracheal aspirate >105 cfu/ml), incidence of tracheobronchial colonization, and tracheal ischemic lesions as defined by a macroscopic score. Pepsin was quantitatively measured in all tracheal aspirates during the 48 hours following randomization. A patient was considered as having abundant microaspiration when >65% of tracheal aspirates were pepsin positive. Patients remained in a semirecumbent position in bed, and a written enteral nutrition protocol was used. All analyses were performed on an intention-to-treat basis.
Patient characteristics were similar in the two groups. The pneumatic device was efficient in controlling Pcuff. Pepsin was measured in 1,205 tracheal aspirates. The percentage of patients with abundant microaspiration (18% vs. 46%, P = 0.002, OR (95% CI) 0.25 (0.11 to 0.59)), pepsin level (median (IQ) 195 (95 to 250) vs. 251 (130 to 390), P = 0.043), and VAP rate (9.8% vs. 26.2%, P = 0.032, 0.30 (0.11 to 0.84)) were significantly lower in the intervention group compared with control group. However, no significant difference was found in rate of patients with tracheobronchial colonization (34% vs. 39%, P = 0.7) or in tracheal ischemia score (4.5 (1 to 6) vs. 4.5 (1 to 7), P = 0.9) between the two groups.
Continuous control of Pcuff is associated with significantly decreased microaspiration of gastric contents in critically ill patients.
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