Experimental determination of the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass.
This study investigated the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass in a canine model. The adequacy of cerebral oxygenation was determined from the adenosine concentration, the oxygen saturation of cerebral venous blood and brain oxyhemoglobin level. In experiment 1, nine beagles were cooled on bypass to a nasopharyngeal temperature of 18 degrees C and the perfusion flow rate was reduced in a stepwise fashion every 30 min from 100 to 50, 30, 20 and 10 ml/kg per min. In experiment 2, six beagles were cooled on bypass as in experiment 1, and flow was maintained at 30 ml/kg per min for 120 min. At a perfusion flow rate of 30 ml/kg per min, adequate cerebral oxygenation was maintained for 120 min. In contrast, perfusion flow rates of 20 and 10 ml/kg per min were associated with cerebral ischemia.
Nara
M
M
Second Department of Surgery, Fukui Medical University, Fukui-Ken, Japan.
Chiba
Y
Y
Niwa
H
H
Kimura
T
T
Ihaya
A
A
Morioka
K
K
Uesaka
T
T
Tsuda
T
T
Muraoka
R
R
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism; D002545:Brain Ischemia / Q000503:physiopathology / Q000517:prevention & control; D002315:Cardiopulmonary Bypass / Q000379:methods* / Q000592:standards; D002343:Carotid Artery, Internal / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D004285:Dogs; D007036:Hypothermia, Induced; D010100:Oxygen / Q000378:metabolism; D010108:Oxyhemoglobins / Q000378:metabolism; D010477:Perfusion; D012449:Safety; D019265:Spectroscopy, Near-Infrared
D010108:Oxyhemoglobins; D000255:Adenosine Triphosphate; D010100:Oxygen