title: The concentration of calcium in neonatal cardioplegia.
abstract: The optimal calcium concentration in cardioplegia for the newborn has not been determined. Therefore, the effect of 0, 0.6, 1.2, 1.8, and 2.4 mmol/L calcium in modified St. Thomas cardioplegia was evaluated in isolated working hearts of 7- to 10-day-old rabbits. Functional recovery was determined by comparing aortic flow, developed pressure, and first derivative of left ventricular pressure (dP/dt) before and after 1 hour of normothermic (37 degrees C) ischemia. As percentages of baseline values, recovery of developed pressure and dP/dt averaged 10% +/- 1% (mean +/- standard error of the mean) and 10% +/- 1% with 0 mmol/L, 46% +/- 7% and 44% +/- 8% with 0.6 mmol/L, 79% +/- 2% and 76% +/- 2% with 1.2 mmol/L, 67% +/- 2% and 61% +/- 5% with 1.8 mmol/L, and 65% +/- 5% and 65% +/- 7% with 2.4 mmol/L calcium, respectively. Significant improvement in recovery of developed pressure and dP/dt was detected when the calcium concentration was increased from 0 to 0.6 mmol/L and from 0.6 to 1.2 mmol/L, but the groups with 1.2, 1.8, and 2.4 mmol/L did not differ from one another significantly in terms of developed pressure and dP/dt recovery. There was no recovery of aortic flow when 0 mmol/L calcium was used; at calcium concentrations of 0.6, 1.2, 1.8, and 2.4 mmol/L, recovery of aortic flow averaged 16% +/- 7%, 63% +/- 10%, 23% +/- 10%, and 36% +/- 11% of baseline values, respectively. Recovery of aortic flow with 1.2 mmol/L calcium was significantly higher than at concentrations of 0.6 and 1.8 mmol/L.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Surgery (Thoracic Section), University of Michigan Medical School, Ann Arbor.
authors.forename: T N
authors.initials: TN
authors.lastname: Zweng
authors.forename: M D
authors.initials: MD
authors.lastname: Iannettoni
authors.forename: E L
authors.initials: EL
authors.lastname: Bove
authors.forename: A K
authors.initials: AK
authors.lastname: Pridjian
authors.forename: M H
authors.initials: MH
authors.lastname: Fox
authors.forename: S F
authors.initials: SF
authors.lastname: Bolling
authors.forename: K P
authors.initials: KP
authors.lastname: Gallagher
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001639:Bicarbonates / Q000032:analysis; D002118:Calcium / Q000008:administration & dosage / Q000494:pharmacology*; D002122:Calcium Chloride / Q000032:analysis; D002314:Cardioplegic Solutions / Q000032:analysis*; D006324:Heart Arrest, Induced; D008274:Magnesium / Q000032:analysis; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D011189:Potassium Chloride / Q000032:analysis; D011817:Rabbits; D012965:Sodium Chloride / Q000032:analysis
chemical_list: D001639:Bicarbonates; D002314:Cardioplegic Solutions; C041711:St. Thomas' Hospital cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride; D002118:Calcium