Hemodynamics and metabolism during surface-induced hypothermia in the dog: A comparison of pH management strategies

Julie A. Swain, Thomas J. McDonald, Robert C. Robbins, Victoria A. Hampshire

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The management of blood pH during hypothermia remains controversial. The present study was designed to determine whether hemodynamics and oxygen consumption during hypothermia are different between the alpha-stat and pH-stat strategies. Theoretical considerations of enzyme kinetics suggest that the alpha-stat strategy would result in a higher oxygen consumption during hypothermia. Because hypothermia is used to decrease oxygen consumption for protection during ischemia, a pH scheme that results in a greater oxygen demand for any level of ischemia would be detrimental. The core temperature of 22 dogs was lowered to 26°C by combined surface cooling and gastric irrigation. Either the alpha-stat (N = 9) or the pH-stat (N = 13) pH strategy was used. The arterial pressure was different between the two groups at 26°C (65 ± 6 vs 85 ± 6 mm Hg, alpha-stat vs pH-stat, respectively, P < 0.05). Neither systemic oxygen consumption nor the Q10 was different between groups. There were no differences in any other hemodynamic parameters. In summary, during moderate hypothermia alpha-stat pH management results in an arterial pressure lower than that of pH-stat management, possibly resulting in improved peripheral perfusion. Despite theoretical predictions, the alpha-stat pH scheme does not result in an oxygen consumption higher than that of the pH-stat scheme.

Original languageEnglish (US)
Pages (from-to)217-222
Number of pages6
JournalJournal of Surgical Research
Issue number3
StatePublished - Mar 1990
Externally publishedYes

ASJC Scopus subject areas

  • Surgery


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