The use of pressure-controlled mechanical ventilation in a swine model of intraoperative pediatric cardiac arrest

Background: Current pediatric resuscitation guidelines suggest that resuscitators using an advanced airway deliver 8-10 breaths per minute while carefully avoiding excessive ventilation. In the intraoperative setting, having a dedicated ventilation rescuer may be difficult because of limited personnel. Continuing pressure-controlled mechanical ventilation during resuscitation for intraoperative cardiac arrest reduces personnel needed and the risk of hyperventilation but might risk hypoventilation during chest compression delivery. Aims: To determine whether the use of pressure-controlled mechanical ventilation at prearrest settings provides normoxia and normocarbia during resuscitation from cardiac arrest. Methods: We retrospectively analyzed combined data from preclinical randomized controlled trials. Two-week-old swine (3-4 kg) underwent asphyxia-induced cardiac arrest. Animals were resuscitated with periods of basic and advanced life support. During resuscitation, pressure-controlled mechanical ventilation was delivered at the prearrest respiratory rate, peak inspiratory pressure, and positive end-expiratory pressure. Arterial blood gases were measured prearrest, at 11 minutes of asphyxia, and at 8 and 20 minutes of cardiopulmonary resuscitation. Results: Piglets (n = 154) received pressure-controlled mechanical ventilation before and during cardiopulmonary resuscitation with a peak inspiratory pressure of 14-15 cm H₂O, positive end-expiratory pressure of 4 cm H₂O, 20 breaths/minute, and an inspiratory:expiratory ratio of 1:2. During asphyxia, the arterial blood gas showed the expected severe hypercarbia and hypoxia. Continuing pressure-controlled mechanical ventilation using prearrest parameters and increasing the FiO₂ to 1.0 returned the PaCO₂ to prearrest levels and slightly increased the partial pressure of arterial oxygen at 8 and 20 minutes of cardiopulmonary resuscitation. Conclusion: In this piglet model of resuscitation from asphyxial arrest, pressure-controlled mechanical ventilation during cardiopulmonary resuscitation at the prearrest ventilator settings with an FiO₂ of 1.0 provides adequate oxygenation and restores normocarbia. Clinical investigation is warranted to determine the benefits of continuing pressure-controlled mechanical ventilation at prearrest parameters during pediatric cardiopulmonary resuscitation.