Gropper MD, PhD, in Miller's Anesthesia, 2020 Tidal Volume 35 A rising heart rate is a good sign that effective ventilation is being delivered. As the lungs aerate and become more compliant, pressure may need to be reduced. Infants who make no respiratory effort may require higher pressures initially. Typically, pressures in the range of 20-30 cm H 2O are suggested as initial settings 51,94 and have been shown to produce reasonable tidal volumes. In the absence of tidal volume monitoring devices, clinicians rely on set peak pressure and clinical signs to deliver safe and effective ventilation. 78 Development and testing of inexpensive, reliable, and accurate techniques to measure and display tidal volume is an important priority in neonatal resuscitation. Avoidance of tidal volumes greater than 8 mL/kg appears reasonable. 55 The ideal target volumes for ventilation of term and preterm infants remain uncertain.

30 Animal studies have shown that high tidal volumes given soon after birth result in reduced oxygenation, increased need for ventilatory support, and instability of cerebral blood flow that increases the risk of brain injury. This means that tidal volumes delivered during PPV are variable and usually much higher than those generated during spontaneous breathing. The actual delivered volume depends on multiple factors-the infant's spontaneous breathing effort, lung compliance, mask leak, obstruction at the mouth and nose, and the resuscitation device used. 56,68 However, they remain the most practical methods of targeting delivered volume given the equipment currently available. Neither of these provide reliable guidance regarding volume delivery. Tidal volumes are not usually measured in the delivery room therefore, clinicians must use peak pressure and clinical judgment of chest rise as a proxy for volume delivery. Martin MBBS, FRACP, in Fanaroff and Martin's Neonatal-Perinatal Medicine, 2020 Peak Inflation Pressures and Tidal Volumes