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

AimDetermine 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 (2.5 kg or 20% of subject body weight) would be associated with a clinically important change in ITP.MethodsIRB-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 ≥2.0 cmH2O was considered clinically significant.Results13 healthy, anesthetized, paralyzed mechanically ventilated children (age: 26 ± 24 m, range: 6.5–87 m; weight: 13 ± 5 kg, range: 7.4–24.8 kg) were enrolled. Peak ETP increased from baseline for all force applications (10% body weight: mean difference of 0.8 cmH2O, p < 0.01; 15% body weight: mean difference of 1.1 cmH2O, p < 0.01; 20% body weight: mean difference of 1.5 cmH2O, p < 0.01; 25% body weight: mean difference of 1.89 cmH2O, p < 0.01). Residual leaning force of ≥2.5 kg was associated with a 2.0 cmH2O change in peak ETP (odds ratio 7.5; CI95 1.5–37.7; p = 0.014) while sternal force ≥20% body weight was not (odds ratio 2.4; CI95 0.6–9.2; p = 0.2).ConclusionIn healthy anesthetized children, changes in ETP were detectable at residual leaning forces as low as 10% of subject body weight. Residual leaning force of 2.5 kg was associated with increases in ETP ≥2.0 cmH2O.