Graduate Student University of Alberta Faculty of Medicine and Dentistry Edmonton, Alberta, Canada
Background: Around 10% of newborn infants require positive pressure ventilation (PPV) at birth, which serves to establish a functional residual capacity, deliver an adequate tidal volume (VT), initiate spontaneous breathing, and facilitate gas exchange while minimizing lung and brain injury. In the delivery room, PPV is routinely provided using a fixed peak inflation pressure with the assumption that this will deliver an adequate VT. However, the delivered VT is not routinely measured and can greatly vary, raising concerns as studies report that high VT delivery can cause lung and brain damage, as well as alter the response to surfactant. An alternative approach may be a novel ventilation device, The Next Step resuscitator (KM Medical, Auckland, New Zealand), which was designed to deliver a predetermined VT and ventilation rate irrespective of airway compliance. Objective: Our objective was to determine the efficacy of the Next Step resuscitator as an alternative ventilation device by comparing targeted VT delivery of 5mL/kg at lung compliances of 0.5 and 1.5mL/cmH2O levels in a post-transitional piglet model using different ventilation (PPV) devices. Design/Methods: Ten newborn piglets (n=8/group) were anesthetized, intubated, and randomized to receive PPV for one minute with a SIB with or without a respiratory function monitor (RFM), T-Piece resuscitator with or without a RFM, Next Step, and Fabian Ventilator with both compliance levels. PPV was performed for 1 minute with each of the devices. All six interventions were completed with the 0.5mL/cmH2O compliance followed by 1.5mL/cmH2O compliance in all piglets in a non-randomized manner. Results: The Next Step and Fabian Ventilator delivered the target VT of 5mL/kg most accurately at both compliance levels. At 0.5 and 1.5mL/cmH2O compliance, respectively, the mean(SD) expired VT with the Next Step was 5.1(0.2) and 5.2(0.6)mL/kg, 4.8(0.5) and 4.4(0.7)mL/kg with the Fabian, 8.9(3.6) and 12.1(5.3)mL/kg with the SIB, 4.5(1.8) and 9.4(3.9)mL/kg with SIB+RFM, 7.4(4.3) and 8.6(1.5)mL/kg with the T-Piece, and 6.4(3.1)mL/kg and 6.5(1.6)mL/kg with T-Piece+RFM. Adding an RFM to either SIB or T-Piece increased the percentage of inflations within target range at a compliance of 0.5mL/cmH2O, while the addition of an RFM increased the percentage of inflations within target range for the T-Piece but not SIB at a compliance of 1.5mL/cmH2O.
Conclusion(s): The Next Step provides consistent VT during PPV, which is comparable to a mechanical ventilator. This warrants further investigation during neonatal resuscitation.
