[EngO3-2] Measurement of esophageal pressure to assess extubation readiness in a neonate with congenital diaphragmatic hernia: its feasibility and usefulness
Background: Congenital diaphragmatic hernia (CDH) is a disease in which intraperitoneal organs occupies the thoracic cavity through diaphragm defects and makes an ipsilateral lung hypoplastic. Diaphragmatic hernia repair is usually performed within several days after birth. Because some degree of tachypnea and increased work of breathing (WOB) after the repair are the rule rather than the exception due to the pulmonary hypoplasia and the malfunction of the diaphragm, assessment of extubation readiness in patients with CDH is often challenging. WOB measured by esophageal pressure could be a reliable indicator for avoiding extubation failure. However, the reliability and usefulness of measuring esophageal pressure in patient with CDH have not been reported.
Case: A 1-month-old boy, who had undergone surgical repair of right CDH two days after birth, had been mechanically ventilated since birth. Since the right lung remained hypoplastic and collapsed, gas exchange was performed almost entirely by the left lung. Upon spontaneous breathing trial at pressure support (PS) of 0cmH2O and positive end-expiratory pressure (PEEP) of 7 cmH2O, respiratory parameters were favorable for extubation: the rapid shallow breathing index was 7.9 and respiratory compliance was 0.7 ml/cmH2O/kg. His respiratory efforts, however, increased as pressure support (PS) decreased; it was therefore uncertain if extubation would be successful. To better judge extubation readiness, we further assessed respiratory muscle strength and work of breathing (WOB) by measuring esophageal pressure (Pes). First, we inserted an esophageal balloon catheter and measured the changes in esophageal pressure (ΔPes) and airway pressure (ΔPaw) during occlusion test to confirm the correct positioning of the catheter. Since the ratio of ΔPes to ΔPaw was 0.81, within a recommended range of 0.8-1.2, esophageal pressure in this case was deemed a reliable surrogate of pleural pressure. Maximal inspiratory pressure was 21mmHg (28.6cmH2O), suggesting that respiratory muscle strength was strong enough for extubation. On the other hand, during the mechanical ventilation with PS of 8cmH2O and PEEP of 6cmH2O, ΔPes was 4cmH2O and the change in transpulmonary pressure was 7cmH2O; based on this results, we speculated WOB would not be very high after extubation. Finally, the patient was extubated successfully without reintubation due to respiratory failure.
Conclusion: Measurement of esophageal pressure in a neonate with CDH is feasible and may help assessing WOB and extubation readiness.
Case: A 1-month-old boy, who had undergone surgical repair of right CDH two days after birth, had been mechanically ventilated since birth. Since the right lung remained hypoplastic and collapsed, gas exchange was performed almost entirely by the left lung. Upon spontaneous breathing trial at pressure support (PS) of 0cmH2O and positive end-expiratory pressure (PEEP) of 7 cmH2O, respiratory parameters were favorable for extubation: the rapid shallow breathing index was 7.9 and respiratory compliance was 0.7 ml/cmH2O/kg. His respiratory efforts, however, increased as pressure support (PS) decreased; it was therefore uncertain if extubation would be successful. To better judge extubation readiness, we further assessed respiratory muscle strength and work of breathing (WOB) by measuring esophageal pressure (Pes). First, we inserted an esophageal balloon catheter and measured the changes in esophageal pressure (ΔPes) and airway pressure (ΔPaw) during occlusion test to confirm the correct positioning of the catheter. Since the ratio of ΔPes to ΔPaw was 0.81, within a recommended range of 0.8-1.2, esophageal pressure in this case was deemed a reliable surrogate of pleural pressure. Maximal inspiratory pressure was 21mmHg (28.6cmH2O), suggesting that respiratory muscle strength was strong enough for extubation. On the other hand, during the mechanical ventilation with PS of 8cmH2O and PEEP of 6cmH2O, ΔPes was 4cmH2O and the change in transpulmonary pressure was 7cmH2O; based on this results, we speculated WOB would not be very high after extubation. Finally, the patient was extubated successfully without reintubation due to respiratory failure.
Conclusion: Measurement of esophageal pressure in a neonate with CDH is feasible and may help assessing WOB and extubation readiness.