Effects of acute hypoxia and reoxygenation in a blood-perfused neonatal heart model.
Newborn (less than 4-day old) piglet hearts (n = 7) were isolated and perfused with blood from a support pig. With use of a reservoir and membrane oxygenator, each heart was perfused for 90 minutes with blood at an O2 saturation of 40% and a pH of 7.4-7.5, at a left atrial pressure of 9 mm Hg, and at an aortic root pressure of 80 mm Hg. Blood saturation was increased to 100%, and the left atrial pressure decreased to 6 mm Hg for 60 minutes. Minute work indexes were calculated for each heart before hypoxia, every 30 minutes during hypoxia, and at 30 and 60 minutes of reoxygenation. Control hearts (n = 8) were treated in an identical fashion, but O2 saturation was maintained at 100%. Myocardial function decreased in the neonatal hearts exposed to hypoxia and reoxygenation. Control hearts did not suffer any significant decrease in function. Nucleotide levels were similar in both groups at the completion of the experiment. Anaerobic metabolism was demonstrated in the hypoxic hearts by net release of lactic acid during the period of hypoxia. This model can be used to study methods of intervention in the working hypoxic neonatal heart.
Sadeghi
A M
AM
Division of Cardiothoracic Surgery, UCLA School of Medicine 90024.
Breda
M A
MA
Laks
H
H
Chang
P A
PA
Laidig
C A
CA
Wu
A
A
Bhuta
S
S
Drinkwater
D C
DC
D000208:Acute Disease; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001769:Blood; D004734:Energy Metabolism; D006321:Heart / Q000503:physiopathology*; D000860:Hypoxia / Q000473:pathology / Q000503:physiopathology*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D010477:Perfusion / Q000379:methods*; D010710:Phosphates / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D013552:Swine
D007773:Lactates; D010710:Phosphates; D011773:Pyruvates; D019344:Lactic Acid; D019289:Pyruvic Acid