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Landé-Edwards membrane oxygenator without pump as total lung prosthesis
The Journal of Thoracic and Cardiovascular Surgery
|February 1, 1975
Summary
This study shows that a Landé-Edwards membrane oxygenator (LEMO) can function as an external artificial lung for dogs. However, prolonged use beyond one hour led to mortality, indicating limitations in long-term extracorporeal breathing.
Area of Science:
- Cardiovascular Surgery
- Respiratory Physiology
- Biomedical Engineering
Background:
- Extracorporeal breathing devices are crucial for supporting patients with respiratory failure.
- The Landé-Edwards membrane oxygenator (LEMO) is a specific type of artificial lung.
- Understanding the performance and limitations of LEMO in vivo is essential for clinical application.
Purpose of the Study:
- To evaluate the efficacy and physiological impact of using a Landé-Edwards membrane oxygenator (LEMO) for total extracorporeal breathing in dogs.
- To determine the maximum duration of safe apnea supported by the LEMO in a canine model.
- To assess hemodynamic and gas exchange parameters during cardiopulmonary bypass with the LEMO.
Main Methods:
- Fourteen anesthetized dogs underwent total pulmonary bypass using a 2 sq. M. Landé-Edwards membrane oxygenator (LEMO) for 1 to 4 hours.
- The LEMO was directly perfused by the right heart, acting as an external artificial lung without external pumps or reservoirs.
- Hemodynamic parameters (pulmonary and systemic arterial pressure, cardiac output, central venous pressure) and electrocardiograms were monitored. Arterial blood gases were analyzed.
Main Results:
- A 2 sq. M. LEMO was adequate for a 10 kg dog, maintaining adequate oxygenation (PO2 > 200 mm. Hg).
- Pulmonary arterial pressure transiently increased, while systemic arterial pressure decreased to 61% of baseline.
- Dogs survived bypass up to 1 hour; survival decreased significantly with longer durations, averaging 3 hours 20 minutes.
- Oxygen transfer was limited (< 20 ml/min/m²) due to hemodilution and hypothermia.
Conclusions:
- The Landé-Edwards membrane oxygenator (LEMO) can function as an effective external artificial lung for short-term extracorporeal breathing in dogs.
- Prolonged apnea exceeding one hour with this LEMO setup leads to mortality, highlighting limitations for extended support.
- Further research is needed to optimize LEMO performance and address limitations like hemodilution and hypothermia for longer durations.