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[A depression of respiratory function following the cardiopulmonary bypass in infants and children]
M Fukasawa1, H Orita, Y Iijima
1Second Department of Surgery, Yamagata University School of Medicine, Japan.
Insights
Pediatric cardiac surgery patients show increased respiratory index (RI) after cardiopulmonary bypass (CPB). Elevated RI post-surgery indicates potential pulmonary dysfunction, linked to preoperative conditions and increased pulmonary blood flow.
Area of Science:
- Pediatric Cardiac Surgery
- Cardiopulmonary Bypass
- Respiratory Physiology
Context:
- Ventricular septal defect (VSD) closure in infants and children (2-44 months) using moderate-hypothermic cardiopulmonary bypass (CPB).
- Monitoring of the respiratory index (RI) as a functional parameter of oxygenation capacity post-CPB.
Purpose:
- To investigate the changes in respiratory index (RI) after cardiopulmonary bypass (CPB) in pediatric patients undergoing VSD closure.
- To identify factors correlating with post-CPB pulmonary dysfunction and prolonged ventilation.
Summary:
- Forty-one pediatric patients exhibited elevated RI levels (2.22 +/- 0.45) at 15 minutes post-CPB, normalizing slightly by 90 minutes but peaking again 12 hours after ICU admission (2.56 +/- 0.64).
- Patients with RI-15 > 1.00 experienced higher RI levels and prolonged mechanical ventilation.
- RI-15 correlated with pulmonary-systemic flow ratio (Qp/Qs) and pulmonary-left ventricular pressure ratio (PA/LV), but not with CPB duration, temperature, or perfusion parameters.
Impact:
- Suggests pulmonary dysfunction post-CPB involves preoperative factors, not solely CPB itself.
- Highlights increased pulmonary blood flow as a potential predictive factor for postoperative oxygenation depression in pediatric cardiac surgery.
Abstract:
Fourty-one patients (2-44 month old) underwent the closure of ventricular septal defect using moderate-hypothermic cardiopulmonary bypass (CPB). The respiratory index (RI) were monitored after CPB, as functional parameters of oxygenation capacity. At 15 min after CPB, there was the increased level in RI (2.22 +/- 0.45; normal value: 0.1-0.37). Thereafter, RI gradually decreased by 90 min after CPB (1.22 +/- 0.19), and again increased reaching peak levels by 12 hrs after ICU-entry (2.56 +/- 0.64). The patients who exceed 1.00 at 15 min after CPB (RI-15) remained higher levels in RI compared to less than 1.00 and had the prolonged controlled ventilation. The RI-15 correlated with pulmonary-systemic flow ratio (Qp/Qs) and pulmonary-left ventricular pressure ratio (PA/LV). There was no significant correlation between RI-15 and CPB factors including CPB time, dilution rate, rectal temperature, flow and perfusion pressure. These results suggest that pulmonary dysfunction following the CPB may not be simply occurred by CPB but also involved by preoperative conditions. An increased pulmonary blood flow might be one of important and predictive factor for the depression of oxygenation following the cardiac surgery in infants and children.