Interstitial pO₂ and high energy phosphates in the canine heart during hypothermic preservation in a new, portable, pulsatile perfusion device

A prototype design of a new portable, hypothermic, pulsatile perfusion organ preservation device was evaluated for its ability to oxygenate cardiac tissue during prolonged hypothermic perfusion storage. The device utilizes a novel application of fluidics technology to achieve simultaneous oxygenation and perfusion. Weighing less than 18 kg the device uses no electrical power. Interstitial pO₂ was compared in canine hearts stored for 12 hours in this device (n = 5) and in static hypothermic storage (n = 5), Temperature was maintained at 4°C in both groups. Effluent from microdialysis probes positioned within the left ventricular wall was analyzed for interstitial pH, pCO₂, pO₂, high energy phosphates, adenosine, and inosine each hour for 12 hours. Initial interstitial pO₂ in both groups exceeded 150 mmHg. In perfused hearts pO₂ declined 30% by the twelfth hour while complete depletion of oxygen within 6 hours was noted in the static storage group. ATP remained low in this group while ADP and AMP peaked at 2 hours and disappeared by 5 hours. Adenosine peaked at 4 hours and declined to low levels by 8 hours. Inosine levels gradually increased during storage and peaked at 12 hours. In the perfused hearts no ATP, ADP or AMP, adenosine or inosine was found interstitially. 780 liters of oxygen were expended during the 12 hours of operation. There was no significant organ weight gain in either group. This portable organ preservation/transport device appears to adequately oxygenate hypothermically stored canine heart tissue for 12 hours at low net perfusion pressure.