Ventilation in pediatric anesthesia: A French multicenter prospective observational study (PEDIAVENT)

Comparison of the tidal volume by the recruitment maneuver combined with positive end-expiratory pressure for mechanically ventilated children

The recruitment maneuver (RM) combined with PEEP to prevent atelectasis have beneficial effects. However, the change in tidal volume (VT) due to RM combined with PEEP in pediatric patients during the induction of general anesthesia is unknown. Therefore, we assessed the effects of RM combined with PEEP on VT. Pediatric patients were divided into three groups: infants, preschool children, and school children. The RM was performed by maintaining pressure control continuous mandatory ventilation (PC-CMV) with a 15 cmH2O and PEEP increase of 5 cmH2O. VT, respiratory function and hemodynamics were monitored before and after RM combined with PEEP. VT (mL) /ideal body weight (kg) before vs. after RM combined with PEEP were 9 vs 12 mL/kg (p < 0.05) in the infants, 9 vs 11 mL/kg (p < 0.05) in the preschool children, 8 vs 10 mL/kg (p < 0.05) in the school children, respectively. HR and BP before and after RM combined with PEEP increased by 2-3% and decreased by 4-7% in all groups. RM combined with PEEP resulted in an increase in VT per ideal body weight (1.1-1.2%). Therefore, this RM combined with PEEP method might improve the lung function in pediatric patients.

Alveolar target ventilation and dead space in children under anaesthesia: The proventiped cohort study

INTRODUCTION

Ventilator settings in children under anaesthesia remain difficult because of the changes in the physiology and the high dead space.

OBJECTIVE

To determine the alveolar minute-volume to sustain normocapnia in children under mechanical ventilation.

DESIGN

A prospective observational study.

SETTINGS

This study was performed between May and October 2019 in a tertiary care children's hospital.

PATIENTS

Children between 2 months and 12 years, weighing between 5 and 40 kg, admitted for general anaesthesia.

INTERVENTION

Volumetric capnography was used to estimate the alveolar and dead space volume (Vd).

MAIN OUTCOME MEASURES

Total and alveolar minute ventilation in (ml kg -1  min -1 ) over 100 breaths.

RESULTS

Sixty patients were included comprising 20 per group: 5 to 10 kg (group 1), 10 to 20 kg (group 2), 20 to 40 kg (group 3). Seven patients were excluded for aberrant capnographic curves. After normalisation to weight, the median [IQR] tidal volume per kilogram was similar between the three groups: 6.5 ml kg -1 [6.0 to 7.5 ml kg -1 ], 6.4  ml kg -1 [5.7 to 7.3  ml kg -1 ], 6.4  ml kg -1 [5.3 to 6.8  ml kg -1 ]; P  = 0.3. Total Vd (in ml kg -1 ) was negatively correlated to weight ( r  = -0.62, 95% confidence interval -0.41 to -0.76, P  < 0.001). The total normalised minute ventilation (ml kg -1  min -1 ) to obtain normocapnia was higher in group 1 than in group 2 and in group 3; 203  ml kg -1  min -1 [175 to 219 ml kg -1  min -1 ], 150  ml kg -1  min -1 [139 to 181  ml kg -1  min -1 ] and 128  ml kg -1  min -1 [107 to 157  ml kg -1  min -1 ]; P  < 0.001 (mean ± SD), but (mean ± SD) alveolar minute ventilation was similar between the three groups; 68 ± 21  ml kg -1  min -1 .

CONCLUSION

Total dead space volume (including apparatus dead space) represents a major component of tidal volume in children less than 30 kg, when using large heat and moisture exchanger filters. The total minute ventilation necessary to achieve normocapnia decreased with increasing weight, while the alveolar minute ventilation remained constant.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier: NCT03901599.