To determine quantitative differences in several routinely measured ventilation parameters using a standardized anesthetic technique and 3 different ventilation modalities in pediatric patients with a ProSeal laryngeal mask airway (PLMA).

Randomized prospective study.

Pediatric hospital of a tertiary care academic medical center.

Thirty-three, American Society of Anesthesiologists classification 1-2, pediatric patients (12 months to 5 years).

Three different ventilation strategies: spontaneous ventilation (SV), pressure support ventilation (PSV), and pressure-controlled ventilation (PCV) were randomly applied to patients who underwent a standardized mask induction with sevoflurane/oxygen and propofol 3 mg/kg and morphine 0.05 mg/kg administered intravenously followed by PLMA insertion. Patients were maintained on sevoflurane and N₂O.

We measured the differences in end-tidal CO₂ (Etco₂), tidal volume, and respiratory rate over time between SV, PSV, and PCV. These data were recorded at 5-minute intervals.

Etco₂ (mm Hg) was significantly higher in the SV vs PSV (P=.016) and vs PCV (P<.001). Tidal volume (mL/kg) was significantly lower in SV vs PSV (P<.001) and vs PCV (P<.001). Respiratory rate (breaths/min) was significantly higher in SV vs PSV (P<.001) and vs PCV (P=.005).

All 3 modes of ventilation using a PLMA were safely used. Our SV group was noted to have a significantly higher Etco₂ when compared with PSV and PCV with a mean Etco₂ over time in excess of 55 mm Hg. PSV and PCV were found to be more appropriate ventilation strategies to more optimally control Etco₂ over time in these patients.