The interaction of subglottic drainage, cuff pressure, and oral care on endotracheal tube fluid leakage: A benchtop study

Background: The types of endotracheal tube, positive end-expiratory pressure (PEEP) level, endotracheal tube cuff pressure level, and nursing activity may influence the occurrence of pulmonary aspiration in ventilated patients with an endotracheal tube, but the evidence on their degree of influence is still inconclusive. Aim: The aim of this study was to examine the effect of endotracheal tubes with or without subglottic secretion drainage on fluid leakage across endotracheal tube cuffs under different PEEP levels, different cuff pressures, and with or without oral care. Method: This was a benchtop study with a multifactorial experimental design using two sets of airway. The two types of endotracheal tubes were tested through 12 scenarios with 240 combinations of different PEEP levels (0, 5, and 10 cmH(2)O), endotracheal tube cuff pressures (15 and 25 cmH(2)O), and oral care (with or without) using two sets of airway manikins. Each scenario lasted for 30 min, and fluid leakage was measured at the end of each scenario. Generalised Linear Model test was used to analyse fluid leak at 30 min (with and without interaction effect). Results: A total of 100 cases showed fluid leakage, with more fluid leakage occurring in low cuff pressure (15 cmH(2)O), no PEEP, and with oral care. Results of the Generalised Linear Model revealed that endotracheal tubes with subglottic secretion drainage, high PEEP (at 10 cmH(2)O), normal cuff pressure (at 25 cmH(2)O), and no oral care demonstrated a significant effect in reducing fluid leakage than endotracheal tubes without subglottic secretion drainage, low PEEP (at 5 or 0 cmH(2)O), and low cuff pressure (at 15 cmH(2)O) (all p < 0.001). However, only the interaction effect of endotracheal tubes with subglottic secretion drainage*high PEEP showed a significant effect on fluid leakage (p < 0.001), with the combination of endotracheal tube*no PEEP producing the greatest volume of fluid leak. Conclusion: Using endotracheal tubes with subglottic secretion drainage, high PEEP, and normal cuff pressure and avoiding excessive endotracheal tube movement during oral care reduced fluid leakage. This study provided strong evidence to inform practice on reducing microaspiration in ventilated patients. (C) 2019 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.