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PEEP and CPAP following open-heart surgery in infants and children
Insights
Positive end-expiratory pressure (PEEP) and continuous positive airway pressure (CPAP) did not significantly improve cardiorespiratory function in infants and children after open-heart surgery. Prolonged expiratory airflow was observed, suggesting limited benefits for these techniques.
Area of Science:
- Cardiology
- Pulmonology
- Pediatric Surgery
Background:
- Post-open-heart surgery management in infants and children often involves mechanical ventilation.
- Positive end-expiratory pressure (PEEP) and continuous positive airway pressure (CPAP) are used to support respiratory function.
- The specific cardiorespiratory effects of these pressures in this vulnerable population require further elucidation.
Purpose of the Study:
- To investigate the cardiorespiratory effects of 5 cm H2O positive end-expiratory pressure (PEEP) during mechanical ventilation.
- To assess the impact of continuous positive airway pressure (CPAP) during spontaneous breathing post-extubation.
- To evaluate the influence of these pressures on cardiac output, oxygen delivery, and respiratory mechanics in pediatric patients after open-heart surgery.
Main Methods:
- Studied 22 infants and children after open-heart surgery.
- Measured cardiorespiratory parameters including cardiac output (thermodilution), intrapulmonary shunting, oxygen consumption, and utilization.
- Recorded respiratory airflow, volume, and pressure during PEEP and CPAP application.
Main Results:
- Neither PEEP nor CPAP significantly altered cardiac output, intrapulmonary shunting, oxygen consumption, or oxygen utilization.
- Patients with preoperative pulmonary hypertension showed no different response compared to those without.
- A significant prolongation of expiratory airflow was noted during both PEEP and CPAP, termed 'expiratory braking' during CPAP, which was associated with increased tidal volume and decreased respiratory rate and minute volume.
Conclusions:
- Sustained end-expiratory pressure (PEEP and CPAP) did not demonstrate significant improvements in cardiopulmonary function in this patient group.
- Potential adverse effects of sustained end-expiratory pressure warrant consideration.
- PEEP and CPAP may be best reserved as temporary measures for compromised respiratory function rather than routine post-operative support.
Abstract:
The cardiorespiratory effects of 5 cm H2O end-expiratory pressure were studied in 22 infants and children an hour after open-heart surgery during mechanical ventilation with positive end-expiratory pressure (PEEP) and prior to endotracheal extubation approximately 15 hours later during spontaneous breathing (CPAP). Thermodilution cardiac output determinations and respiratory airflow, volume and pressure recordings were made to assess the effects of airway pressure changes on the respiratory waveform and oxygen delivery. Neither PEEP nor CPAP had a significant effect on cardiac output, intrapulmonary shunting, oxygen consumption, or oxygen utilization. Patients who had had pulmonary hypertension preoperatively did not behave differently from those without pulmonary hypertension when removed from ventilatory supprot. Expiratory airflow was significantly prolonged when positive end-expiratory pressure existed during both controlled and spontaneous respiration. During CPAP, this "expiratory braking" was associated with an increase in tidal volume and decreases in respiratory rate and minute volume. Because of the lack of improvement in cardiopulmonary function in this group of patients, and the possibility of untoward effects from sustained end-expiratory pressure, PEEP and CPAP might properly be reserved as temporary supportive techniques should respiratory function be compromised.