Tidal Volume Delivery during the Anesthetic Management of Neonates Is Variable.

OBJECTIVES

To describe expiratory tidal volume (V) during routine anesthetic management of neonates at a single tertiary neonatal surgical center, as well as the proportion of V values within the range of 4.0-8.0 mL/kg.

STUDY DESIGN

A total of 26 neonates needing surgery under general anesthesia were studied, of whom 18 were intubated postoperatively. V was measured continuously during normal clinical care using a dedicated neonatal respiratory function monitor (RFM), with clinicians blinded to values. V, pressure, and cardiorespiratory variables were recorded regularly while intubated intraoperatively, during postoperative transport, and for 15 minutes after returning to the neonatal intensive care unit (NICU). In addition, paired V values from the anesthetic machine were documented intraoperatively.

RESULTS

A total of 2597 V measures were recorded from 26 neonates. Intraoperative and postoperative transport expiratory V values were highly variable compared with the NICU V (P < .0001, Kruskal-Wallis test), with 51% of inflations outside the 4.0-8.0 mL/kg range (35% and 38% of V >8.0 mL/kg, respectively), compared with 29% in the NICU (P < .001, χ test). The use of a flow-inflating bag resulted in a median (range) V of 8.5 mL/kg (range, 5.3-11.4 mL/kg) vs 5.6 ml/kg (range, 4.3-7.9 mL/kg) using a Neopuff T-piece system (P < .0001, Mann-Whitney U test). The mean anesthetic machine expiratory V was 3.2 mL/kg (95% CI, -4.5 to 10.8 mL/kg) above RFM.

CONCLUSIONS

V is highly variable during the anesthetic care of neonates, and potentially injurious V is frequently delivered; thus, we suggest close V monitoring using a dedicated neonatal RFM.