Effects of two different crystalloid cardioplegic solutions assessed by myocardial pH, tissue lactate content and energy metabolism.
OBJECTIVE
The influence of composition of crystalloid cardioplegia is imprecise in clinical practice. Therefore, we investigated changes in intramyocardial pH, tissue lactate content and energy metabolism during cardioplegic arrest with 2 different crystalloid cardioplegic solutions.


METHODS
Twenty patients were randomly allocated to 2 groups: 10 patients had crystalloid cardioplegia buffered with bicarbonate (neutral pH of 7.8 at 20 degrees) with no additives (St Thomas' II solution) and 10 patients had a non buffered crystalloid cardioplegia (mildly acidic pH of 7.4 at 20 degrees) enriched with glutamate and mannitol (Menasché's solution). Tissue lactate and energy metabolism were measured on myocardial biopsy specimens and intramyocardial pH were continuously measured during cardioplegic arrest by a miniature glass electrode.


RESULTS
There were no statistical differences in hemodynamic results and in AMP, ADP, ATP, lactate values measured on biopsy specimens. The curves of intramyocardial pH were very similar in the 2 groups, the median values were 7.42 +/- 0.1 in group 1 and 7.41 +/- 0.1 in group 2 (temperature corrected values) and the areas under the curves were 260 +/- 4 and 259 +/- 4 in groups 1 and 2 respectively (P = NS).


CONCLUSIONS
Glutamate provided no additive metabolic myocardial protection, bicarbonate had a weak buffering capacity in cold cardioplegic solutions and the 2 studied crystalloid solutions warranted a good myocardial protection in clinical practice.
Bical
O M
OM
Department of Cardiac Surgery, Hospital Saint Joseph, Paris, France.
Gerhardt
M F
MF
Paumier
D
D
Gaillard
D
D
Landais
P
P
Fromes
Y
Y
Foiret
J C
JC
Trivin
F
F
Vanetti
A
A
D000136:Acid-Base Equilibrium / Q000187:drug effects* / Q000502:physiology; D000368:Aged; D001639:Bicarbonates; D001706:Biopsy; D002122:Calcium Chloride; D002314:Cardioplegic Solutions; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005260:Female; D018698:Glutamic Acid / Q000008:administration & dosage; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008274:Magnesium; D008297:Male; D008353:Mannitol / Q000008:administration & dosage; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D011189:Potassium Chloride; D012965:Sodium Chloride
D001639:Bicarbonates; D002314:Cardioplegic Solutions; C041711:St. Thomas' Hospital cardioplegic solution; D019344:Lactic Acid; D018698:Glutamic Acid; D008353:Mannitol; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride