Document Detail

The effect of intramyocardial pH on functional recovery in neonatal hearts receiving St. Thomas' Hospital cardioplegic solution during global ischemia.
MedLine Citation:
PMID:  1495295     Owner:  NLM     Status:  MEDLINE    
The experiments in the present study were designed to address two issues: Is it possible to manipulate intramyocardial pH in neonatal hearts with different buffers in cardioplegic solution and, if so, do differences in intramyocardial pH during ischemia influence functional recovery? Isolated working hearts from 7- to 10-day-old rabbits underwent 60 minutes of cardioplegic arrest at 37 degrees C with cardioplegic washouts at the onset of ischemia and at 30 minutes. Hearts were reperfused with oxygenated physiologic saline solution (pH = 7.4), returned to the working mode for 30 minutes, and hemodynamic measurements were obtained to compare with baseline values. Intramyocardial pH was held constant during the ischemic interval by infusing cardioplegic solution containing different buffers: histidine (pK 6.0 at 37 degrees C), bicarbonate (pK 6.4), or tromethamine (pK 8.1). The intramyocardial pH was measured continuously with a Khuri glass electrode system (Vascular Technology, Inc., North Chelmsford, Mass.). Cardioplegic solutions buffered to pH values of 6.0 (histidine), 7.4 (bicarbonate), and 8.0 (tromethamine) were associated with ischemic intramyocardial pH values of 6.3 +/- 0.03, 7.02 +/- 0.05, and 7.88 +/- 0.06, respectively. Functional recovery was best in the acidic (histidine) and worst in the basic (tromethamine) groups. Recoveries of developed pressure, the rate of rise of pressure over time, and aortic flow were significantly better for each parameter in the bicarbonate-treated compared with the tromethamine-treated hearts (p less than 0.005). Recovery in the histidine group, however, was superior to that in both the bicarbonate-treated and the tromethamine-treated hearts (p less than 0.005). Regression analysis demonstrated that a significant inverse relationship existed between functional recovery and intramyocardial pH, supporting the conclusions that intramyocardial pH is an important determinant of functional recovery in the neonatal heart and that acidic conditions during normothermic ischemia optimize preservation of myocardial function.
M D Iannettoni; E L Bove; M H Fox; M A Groh; S F Bolling; K P Gallagher
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  104     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  1992 Aug 
Date Detail:
Created Date:  1992-09-04     Completed Date:  1992-09-04     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:  333-43     Citation Subset:  AIM; IM    
Department of Surgery (Thoracic Section), University of Michigan Medical School, Ann Arbor.
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MeSH Terms
Animals, Newborn / physiology*
Bicarbonates / pharmacology
Calcium Chloride / pharmacology
Cardioplegic Solutions / pharmacology*
Hemodynamics / physiology*
Histamine / pharmacology
Hydrogen-Ion Concentration
Magnesium / pharmacology
Myocardial Reperfusion Injury / physiopathology*
Myocardium / metabolism*
Potassium Chloride / pharmacology
Sodium Chloride / pharmacology
Tromethamine / pharmacology
Grant Support
Reg. No./Substance:
0/Bicarbonates; 0/Cardioplegic Solutions; 0/St. Thomas' Hospital cardioplegic solution; 10043-52-4/Calcium Chloride; 51-45-6/Histamine; 7439-95-4/Magnesium; 7447-40-7/Potassium Chloride; 7647-14-5/Sodium Chloride; 77-86-1/Tromethamine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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