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Negative-pressure ventilation improves cardiac output after right heart surgery
L S Shekerdemian1, D F Shore, C Lincoln
1Department of Pediatrics, Royal Brompton Hospital, London, UK.
Insights
Negative-pressure ventilation significantly improved cardiac output in children after complex heart surgery. This method enhanced stroke volume and reduced vascular resistance, offering a potential therapy for low cardiac output states.
Area of Science:
- Pediatric Cardiology
- Cardiovascular Surgery
- Respiratory Physiology
Background:
- Low cardiac output state is a common complication after Fontan-type operations and tetralogy of Fallot repair.
- Effective postoperative management is crucial for these high-risk pediatric patients.
Purpose of the Study:
- To investigate the impact of negative-pressure ventilation on cardiac output in children post-right heart surgery.
- To evaluate changes in stroke volume, vascular resistance, and oxygenation during negative-pressure ventilation.
Main Methods:
- Evaluated 11 children in the early postoperative period after right heart surgery.
- Compared volume-cycled intermittent positive-pressure ventilation with high-frequency oscillatory negative-pressure ventilation (Hayek oscillator).
- Measured cardiac output using the direct Fick method and oxygen consumption via respiratory mass spectrometry.
Main Results:
- Negative-pressure ventilation increased cardiac output by 46% (P = .005) and stroke volume by 48.5% (P = .005).
- Heart rate remained unchanged, while mixed venous saturation increased by 4.6% (P < .02).
- Systemic and pulmonary vascular resistances were significantly reduced during negative-pressure ventilation (P < .05 and P < .03, respectively).
Conclusions:
- Negative-pressure ventilation is an effective method for improving cardiac output in pediatric patients following total cavopulmonary connection and tetralogy of Fallot repair.
- This ventilatory strategy may serve as a valuable therapeutic option for managing low cardiac output states in children post-cardiac surgery.
Background:
A low cardiac output state can complicate the postoperative course of patients undergoing Fontan-type operations and tetralogy of Fallot repair.
Methods And Results:
We investigated the effect of negative-pressure ventilation on cardiac output in 11 children in the early postoperative period after right heart surgery. All patients were initially ventilated with volume-cycled intermittent positive-pressure ventilation, and negative-pressure ventilation was delivered with the Hayek external high-frequency oscillator. Cardiac output was calculated by the direct Fick method, oxygen consumption being measured by respiratory mass spectrometry. Cardiac output was measured during intermittent positive-pressure ventilation and after 15 minutes of negative-pressure ventilation. Negative-pressure ventilation improved the cardiac output by a mean of 46% (P = .005). Heart rate did not change, and stroke volume increased by a mean of 48.5% (P = .005). Mixed venous saturation increased by 4.6% (P < .02), and consequently arteriovenous oxygen content difference fell significantly (P = .01). The systemic and pulmonary vascular resistances were reduced significantly during negative-pressure ventilation (P < .05 and P < .03, respectively).
Conclusions:
Negative-pressure ventilation improves cardiac output in children after total cavopulmonary connection and tetralogy of Fallot repair and may prove to be an important therapeutic option in children with the low cardiac output state.