Expiratory CO2 as the first sign of successful ventilation during neonatal resuscitation.

Three-lead electrocardiography and expired CO2 monitoring were used during positive pressure ventilation of seven non-intubated newborns (gestational age, 31-37 weeks; birthweight, 1503-2885 g). In all cases, adequate CO2 (>15 mmHg) was detected prior to the achievement of stable heart rate (>100 beats/min). The delay between detection of adequate CO2 and improvement of bradycardia ranged from 8 to 73 s (median, 15 s). Inadequate expired CO2 during positive pressure ventilation indicates airway obstruction or poor aeration of the newborn lungs. Thus, positive expiratory CO2 can be the first recognizable sign of successful ventilation during neonatal resuscitation.