Transcutaneous Carbon Dioxide Monitoring During Weaning From Mechanical Ventilation in Children: The WeanCO₂ Study

Spontaneous breathing trial (SBT) is recommended during weaning from mechanical ventilation (MV), but objective and easy tools lack to identify pediatric weaning failure. We aimed to assess whether changes in estimated arterial CO₂ (PaCO₂) derived from transcutaneous measurements (P_TCCO₂) were associated with pediatric weaning failure.

Children (age 72 h -18 years) with MV > 12 h were continuously monitored using a transcutaneous sensor to estimate PaCO₂ from skin CO₂ tension (P_TCCO₂). Values were recorded during SBT (30 min on positive end-expiratory pressure (PEEP) +5 cmH₂O, with pressure support of +5 cmH₂O for endotracheal tubes with internal diameter ≤ 3.5 mm), then up to 6 h after extubation. Mean P_TCCO₂ and P_TCCO₂ changes during SBT, and after extubation, were retrospectively collected to evaluate their association with SBT failure and extubation failure (reintubation within 48 h).

Eighty children (median [IQR] age 1.1 [0.3; 8.7] years) were included, with 89 SBT (14 failures, 75 successes). Sixty-four patients were extubated following their first SBT, with 10 (16%) extubation failures. P_TCCO₂ changes were not associated with SBT and extubation failures. Patients who failed extubation had a higher mean P_TCCO₂ value after extubation as compared to those who were successfully extubated (mean P_TCCO₂ of 51.8 [46.2; 55.4] vs. 42.3 [37.5; 47.2] mmHg, p = 0.02). The difference between the maximal P_TCCO₂ value within the 2 h following extubation and the value at extubation were higher in patients who failed extubation (ΔP_TCCO₂ of 20 [9.1; 26] vs. 6.8 [2.9; 9.7] mmHg, p < 10^-2).

Early post-extubation increase in estimated PaCO₂ was associated with extubation failure, whereas P_TCCO₂ changes during SBT were not.