Document Detail

Chronic hypoxia: a model for cyanotic congenital heart defects.
MedLine Citation:
PMID:  12091815     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: The postoperative course of cyanotic children is generally more complicated than that of acyanotic children. A possible reason is reoxygenation injury at the beginning of cardiopulmonary bypass. In this study we tested the hypothesis that reoxygenation of chronically hypoxic hearts is worse than that of normoxic hearts. METHODS: Two groups of rats (n = 9 each) were exposed to either room air (fraction of inspired oxygen, 0.21%) or chronic hypoxia (fraction of inspired oxygen, 0.10%) for 2 weeks. Hearts were then isolated and perfused for 30 minutes with hypoxic buffer (oxygen saturation, 10%), followed by 30 minutes of reoxygenation (oxygen saturation, 100%). RESULTS: In hypoxic rats hematocrit values, hemoglobin concentrations, and red cells were higher (69% +/- 6% vs 40% +/- 6%, 219 +/- 14 vs 124 +/- 12 g/L, and 10.30 +/- 0.6 vs 6.32 +/- 0.5/microL/1000, respectively; P <.0001); the amount of ingested food was less (22.3 +/- 4.8 vs 30.7 +/- 3.9 g/d, P <.001), as was the amount of ingested water (21.0 +/- 3.1 vs 50.4 +/- 14.6 mL/d, P <.0001); and body weight was lower (182 +/- 14.2 vs 351 +/- 40.1 g, P <.0001), as was heart weight (1107 +/- 119 vs 1312 +/- 128 mg, P <.005). The heart weight/body weight ratio was higher (6.10 +/- 0.8 vs 3.74 +/- 0.1 mg/g, P <.0001). Systolic and diastolic functions, not different during the hypoxic baseline period, were more impaired in hypoxic than in normoxic hearts after the reoxygenation, whereas coronary resistance remained lower. During the hypoxic perfusion, the venous partial pressure of oxygen remained low in both groups, whereas during reoxygenation, partial pressure of oxygen was higher in hypoxic hearts, with a lower (P <.01) oxygen uptake. During hypoxic baseline adenosine triphosphate turnover, lactate production and lactate turnover were lower in hypoxic hearts (P <.005, P <.0001, and P <.0001, respectively). CONCLUSIONS: Body and blood values are severely affected by chronic hypoxia, and the cardiac effects of uncontrolled reoxygenation after chronic hypoxia are more severe than after acute hypoxia.
Antonio F Corno; Giuseppina Milano; Michele Samaja; Piergiorgio Tozzi; Ludwig K von Segesser
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  124     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-07-01     Completed Date:  2002-08-06     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  United States    
Other Details:
Languages:  eng     Pagination:  105-12     Citation Subset:  AIM; IM    
Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
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MeSH Terms
Adenosine Triphosphate / metabolism
Anoxia / physiopathology*
Cardiopulmonary Bypass*
Chronic Disease
Cyanosis / physiopathology
Disease Models, Animal
Heart Defects, Congenital / surgery*
Hemodynamics / physiology
Lactic Acid / metabolism
Myocardial Reperfusion Injury / physiopathology*
Myocardium / metabolism
Oxygen Consumption
Rats, Sprague-Dawley
Time Factors
Reg. No./Substance:
50-21-5/Lactic Acid; 56-65-5/Adenosine Triphosphate
Comment In:
J Thorac Cardiovasc Surg. 2002 Jul;124(1):16-9   [PMID:  12091803 ]
J Thorac Cardiovasc Surg. 2002 Jul;124(1):14-5   [PMID:  12091802 ]

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