Effect of residual leaning force on intrathoracic pressure during mechanical ventilation in children.

ABSTRACT

AIM: Determine the effect of residual leaning force on intrathoracic pressure (ITP) in healthy children receiving mechanical ventilation. We hypothesized that application of significant residual leaning force (2.5kg or 20% of subject body weight) would be associated with a clinically important change in ITP. METHODS: IRB-approved pilot study of healthy, anesthetized, paralyzed mechanically ventilated children (6 months to 7 years). Peak endotracheal pressure (ETP), a surrogate of ITP, was continuously measured before and during serial incremental increases in sternal force from 10% to 25% of the subject's body weight. A delta ETP of >or=2.0cmH(2)O was considered clinically significant. RESULTS: 13 healthy, anesthetized, paralyzed mechanically ventilated children (age 26+/-24m, range 6.5-87m; weight 13+/-5kg, range 7.4-24.8kg) were enrolled. Peak ETP increased from baseline for all force applications (10% body weight mean difference of 0.8cmH(2)O, p<0.01; 15% body weight mean difference of 1.1cmH(2)O, p<0.01; 20% body weight mean difference of 1.5cmH(2)O, p<0.01; 25% body weight mean difference of 1.89cmH(2)O, p<0.01). Residual leaning force of >or=2.5kg was associated with a 2.0cmH(2)O change in peak ETP (odds ratio 7.5; CI(95) 1.5-37.7; p=0.014) while sternal force >or=20% body weight was not (odds ratio 2.4; CI(95) 0.6-9.2; p=0.2). CONCLUSION: In healthy anesthetized children, changes in ETP were detectable at residual leaning forces as low as 10% of subject body weight. Residual leaning force of 2.5kg was associated with increases in ETP >or=2.0cmH(2)O.