Total arteriovenous CO2 removal: simplifying extracorporeal support for respiratory failure.

Abstract

BACKGROUND:

To reduce the complexity, complications, and cost of conventional extracorporeal membrane oxygenation, we have developed a technique of simplified arteriovenous extracorporeal CO2 removal (AVCO2R) with a low-resistance membrane gas exchanger for total CO2 removal to provide lung rest in the setting of severe respiratory failure.

METHODS:

We initially used AVCO2R in healthy animals to quantify the gas exchange capabilities of the system and establish ventilator management protocols for the subsequent studies of AVCO2R in a large animal model of respiratory failure secondary to a severe smoke inhalation injury.

RESULTS:

In healthy sheep the maximum spontaneous arteriovenous flow ranged from 1,350 to 1,500 mL/min, whereas CO2 removal plateaued at a blood flow of approximately 1,000 mL/min in which 112 +/- 3 mL/min CO2 was removed, allowing an 84% reduction in the minute ventilation of from 6.9 +/- 0.8 L/min to 1.1 +/- 0.4 L/min (p < 0.01) without triggering hypercapnia. A subsequent reduction in extracorporeal flow at a reduced minute volume led to the development of hypercapnia only if it decreased to less than 500 mL/min. We also applied AVCO2R in mechanically ventilated sheep with a severe smoke inhalation injury and removed 95% (111 +/- 4 mL/min) of the total CO2 production. This allowed the minute ventilation to be reduced by 95% and the peak inspiratory pressures by 52% (both p < 0.05) over 6 hours and produced no adverse hemodynamic effects. The partial pressure of arterial oxygen was maintained above 100 mm Hg at a maximally reduced minute volume. The mean AVCO2R flow was 1,213 +/- 29 mL/min, averaging 27% +/- 1% of the cardiac output.

CONCLUSIONS:

We conclude that AVCO2R in a simple arteriovenous shunt is a less complicated technique than extracorporeal membrane oxygenation and is capable of total CO2 removal that allows a significant reduction in the minute ventilation and peak airway pressure during severe respiratory failure.

• Authors: R L Brunston Jr, J B Zwischenberger, W Tao, V J Cardenas Jr, D L Traber, A Bidani
• Journal: The Annals of thoracic surgery (Ann Thorac Surg) Vol. 64 Issue 6 Pg. 1599-604; discussion 1604-5 (Dec 1997) ISSN: 0003-4975 [Print] Netherlands
• PMID: 9436542 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Carbon Dioxide

Topics

• Animals
• Arteriovenous Shunt, Surgical (methods)
• Carbon Dioxide (blood)
• Extracorporeal Circulation (methods)
• Female
• Respiratory Insufficiency (therapy)
• Sheep
• Smoke Inhalation Injury (complications)