Effects of Tracheal Intubation and PEEP on Respiratory Mechanics in Children Without Lung Injury Under General...

Data on the physiological impact of tracheal intubation and positive end-expiratory pressure (PEEP) on respiratory mechanics in anesthetized children are scarce. We aimed to evaluate the mechanical effects of intubation and PEEP in children without lung pathology under general anesthesia.

Prospective physiologic experimental crossover study, in children under 15 years scheduled for elective surgery. After anesthesia induction and neuromuscular blockade, volume-controlled ventilation was initiated. Respiratory mechanics were assessed before (mask ventilation) and after tracheal intubation, at PEEP 0 and 5 cmH₂O. Measured variables included peak inspiratory (PIP), plateau (P_PLAT), and total expiratory pressures (tPEEP). Calculated parameters were compliance (Crs), driving pressure (ΔP), and mechanical power (MP). A mixed linear regression model was used.

60 patients were included. Median age 58.0 (18.0-84.0) months. Intubation increased PIP-P_PLAT + 23.9% (p < 0.001), Raw +16.4% (p = 0.011), and ΔP + 20.4% (p < 0.001); and decreased Crs -14% (p = 0.001). PEEP during mask ventilation reduced ΔP 29.1% (p < 0.001) and increased Crs 46.7% (p < 0.001). Combined intubation and PEEP reduced ΔP (-7.9%, p = 0.002) and increased Crs (+19.6%, p < 0.001). PEEP raised MP both during mask ventilation (+50%) and after intubation (+83.3%, both p < 0.001). Children under 2 years showed higher Raw than older children across all conditions (p < 0.001), but similar behavior in ΔP and Crs.

PEEP and intubation induce changes in respiratory mechanics. While tracheal intubation increases PIP and ΔP, and decreases Crs, the addition of PEEP partially mitigates these effects on airway pressures, but not on MP. These results suggest a deterioration of both the resistive and elastic components during MV.

This project was registered and approved for implementation by the Pediatric Hospital Center Pereira Rossell Institutional Review Board and registered in the Ministry of Public Health (#7647719). Informed and signed consent was obtained from all the children's parents or responsible guardians. All procedures in this study were performed in accordance with the Declaration of Helsinki.