Journal article
Hypothermic acid-base management does not affect cerebral metabolic rate for oxygen at 27° C: A study during cardiopulmonary bypass in rabbits
Anesthesiology, Vol.79(3), pp.580-587
1993
DOI: 10.1097/00000542-199309000-00023
PMID: 8363085
Abstract
BACKGROUND: It has been contended that, during cardiopulmonary bypass at 27 degrees C, pH-stat management decreases cerebral metabolic rate for oxygen (CMRO2) more than alpha-stat management. In contrast, other studies have not found CMRO2 to differ between techniques. Using each animal as its own control, the authors assessed the effect of alpha-stat versus pH-stat management of CMRO2, cerebral blood flow (CBF), and brain oxygen extraction during cardiopulmonary bypass at 27 degrees C.METHODS: Fourteen New Zealand White rabbits, anesthetized with fentanyl and diazepam, underwent cardiopulmonary bypass at 27 degrees C (membrane oxygenator, centrifugal pump, and bifemoral arterial perfusion). Group 1 animals (n = 7) had alpha-stat management for the initial 65-70 min of bypass, and were then changed to pH-stat management for the remaining 30 min of bypass. Group 2 animals (n = 7) had pH-stat management for the initial 65-70 min of bypass, and were then changed to alpha-stat management for the remaining 30 min. Measurement of CBF (radiolabeled microspheres), CMRO2 (CBF x brain arterial-venous oxygen content difference), brain temperature, systemic hemodynamics, and arterial blood gases were made in each animal under both alpha-stat and pH-stat conditions.RESULTS: CMRO2 did not differ between alpha-stat and pH-stat conditions (1.4 +/- 0.3 ml.100 g-1.min-1; median +/- quartile deviation), and was independent of order of determination. Changes in CBF between alpha-stat and pH-stat conditions were associated with proportional opposite changes in cerebral oxygen extraction. Cerebral blood flow was significantly greater with pH-stat management than with alpha-stat management (37 +/- 5 vs. 30 +/- 3 ml.100 g-1.min-1, respectively). The CBF response to changing PaCO2 was significantly greater when going from alpha-stat to pH-stat conditions (group 1) than in the reverse order (group 2).CONCLUSIONS: During cardiopulmonary bypass at 27 degrees C, hypothermic acid-base management has no measurable effect on CMRO2. CMRO2 was neither extraction limited nor dependent on either PaCO2, CBF, or hemoglobin oxygen affinity differences between alpha-stat and pH-stat management. Cerebral blood flow responses to changing CMRO2 depend on the "starting" conditions, with alpha-stat management appearing to better preserve CBF reactivity than pH-stat management.
Details
- Title: Subtitle
- Hypothermic acid-base management does not affect cerebral metabolic rate for oxygen at 27° C: A study during cardiopulmonary bypass in rabbits
- Creators
- B. J HindmanF DexterJ CutkompTom SmithJ. H Tinker
- Resource Type
- Journal article
- Publication Details
- Anesthesiology, Vol.79(3), pp.580-587
- DOI
- 10.1097/00000542-199309000-00023
- PMID
- 8363085
- NLM abbreviation
- Anesthesiology
- ISSN
- 0003-3022
- eISSN
- 1528-1175
- Language
- English
- Date published
- 1993
- Academic Unit
- Health Management and Policy; Anesthesia
- Record Identifier
- 9983806277602771
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