Lactate extraction and myocardial damage after countershock at different energy levels

Mary S. Maxwell, Abe DeAnda, Ross Vickery, David M. Gaba

Research output: Contribution to journalArticle

Abstract

The relationship between myocardial lactate metabolism and the energy dose of direct countershock was studied in 15 dogs anesthetized with halothane. Five dogs received two shocks of 5 joules delivered energy each, five animals received two shocks of 10 joules delivered energy each, and five dogs received two shocks of 20 joules delivered energy each. All animals had positive myocardial lactate extraction in the baseline state (5 joules, 38% ± 23.7 (SD); 10 joules, 59.6% ± 11.4; 20 joules, 38% ± 11.1). Lactate extraction after countershock progressively decreased with increasing energy dose and then returned to baseline. The maximal reduction in percent lactate extraction increased with increasing energy dose (5 joules, 13.9% ± 16.1; 10 joules, 33% ± 37; 20 joules, 30.5% ± 37.5) and seemed to reach a threshold below which no further decrease occurred. Myocardial damage, as measured by a damage index derived from myocardial uptake of technetium-99 pyrophosphate, increased steadily with increasing energy dose (2.0 ± 2.5 with 5-joule shocks; 38 ± 32 with 10 joules; and 99 ± 70 with 20 joules). These results show a consistent reduction in aerobic metabolism immediately following electric countershock. Even at low-energy doses, myocardial lactate extraction showed a detectable decrease and at higher energies approached net lactate production. Reductions of global lactate extraction did not completely predict the amount of myocardial damage. Localized measures of anaerobic metabolism or mitochondrial function might provide a better correlation with localized damage.

Original languageEnglish (US)
Pages (from-to)341-345
Number of pages5
JournalJournal of Cardiothoracic Anesthesia
Volume2
Issue number3
DOIs
StatePublished - Jun 1988
Externally publishedYes

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Anesthesiology and Pain Medicine

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