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Mild hypothermia has minimal effects on the tolerance to severe progressive normovolemic anemia in swine

Perez de Sá, Valéria LU ; Roscher, Roger LU ; Cunha Goncalves, Doris LU ; Larsson, A and Werner, Olof LU (2002) In Anesthesiology 97(5). p.1189-1197
Abstract
Background: The benefits of hypothermia during acute severe anemia are not entirely settled. The authors hypothesized that cooling would improve tolerance to anemia. Methods: Eight normothermic (38.0 +/- 0.5degreesC) and eight hypothermic (32.0 +/- 0.5degreesC) pigs anesthetized with midazolam-fentanyl-vecuronium-isoflurane (0.5% inspired concentration) were subjected to stepwise normovolemic hemodilution (hematocrit, 15%, 10%, 7%, 5%, 3%). Critical hemoglobin concentration (Hgb(CRIT)) and critical oxygen delivery (DO2CRIT), i.e., the hemoglobin concentration (Hgb) and oxygen delivery (DO2) at which oxygen consumption (VO2 independently measured by indirect calorimetry) was no longer sustained, and Hgb at the moment of death, defined... (More)
Background: The benefits of hypothermia during acute severe anemia are not entirely settled. The authors hypothesized that cooling would improve tolerance to anemia. Methods: Eight normothermic (38.0 +/- 0.5degreesC) and eight hypothermic (32.0 +/- 0.5degreesC) pigs anesthetized with midazolam-fentanyl-vecuronium-isoflurane (0.5% inspired concentration) were subjected to stepwise normovolemic hemodilution (hematocrit, 15%, 10%, 7%, 5%, 3%). Critical hemoglobin concentration (Hgb(CRIT)) and critical oxygen delivery (DO2CRIT), i.e., the hemoglobin concentration (Hgb) and oxygen delivery (DO2) at which oxygen consumption (VO2 independently measured by indirect calorimetry) was no longer sustained, and Hgb at the moment of death, defined prospectively as the point when VO2 decreased below 40 nil/min, were used to assess the tolerance of the two groups to progressive isovolemic anemia. Results: At hematocrits of 15% and 10% (Hgb, 47 and 31 g/l), VO2 was maintained in both groups by an increase (P < 0.001) in cardiac output (CO) and extraction ratio (ER; P < 0.001) with unchanged mean arterial lactate concentration (L-art.). At hematocrit of 7% (Hgb, 22 g/l), all normothermic but no hypothermic animals had DO2-dependent VO2. No normothermic and three hypothermic animals survived to 5% hematocrit (Hgb, 15 g/l), and none survived to 3%. Hgb(CRIT) was 23 +/- 2 g/l and 19 +/- 6 g/l (mean +/- SD) in normothermic and hypothermic animals, respectively (P = 0.053). Hgb at death was 19 +/- 3 g/l versus 14 +/- 4 g/l (P = 0.015), and DO2CRIT was 8.7 +/- 1.7 versus 4.6 +/- 0.8 ml.kg(-1).min(-1) (P < 0.001). Conclusion: During progressive normovolemic hemodilution in pigs, hypothermia did not significantly change Hgb(CRIT), but it decreased the Hgb at death, i.e., short-term survival was prolonged. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Anesthesiology
volume
97
issue
5
pages
1189 - 1197
publisher
Lippincott Williams & Wilkins
external identifiers
  • pmid:12411805
  • wos:000179034600023
  • scopus:0036841255
ISSN
1528-1175
language
English
LU publication?
yes
id
18696733-fc53-4504-b1b1-66ec26db9623 (old id 324330)
alternative location
http://www.anesthesiology.org/pt/re/anes/fulltext.00000542-200211000-00024.htm;jsessionid=Hr2NlVZp4WprG3QYkPmCHkX7TTrXDY3J7PLNQbhh46fXnZPmz1kR!1821113646!181195629!8091!-1
date added to LUP
2007-11-02 15:41:24
date last changed
2017-01-01 04:38:56
@article{18696733-fc53-4504-b1b1-66ec26db9623,
  abstract     = {Background: The benefits of hypothermia during acute severe anemia are not entirely settled. The authors hypothesized that cooling would improve tolerance to anemia. Methods: Eight normothermic (38.0 +/- 0.5degreesC) and eight hypothermic (32.0 +/- 0.5degreesC) pigs anesthetized with midazolam-fentanyl-vecuronium-isoflurane (0.5% inspired concentration) were subjected to stepwise normovolemic hemodilution (hematocrit, 15%, 10%, 7%, 5%, 3%). Critical hemoglobin concentration (Hgb(CRIT)) and critical oxygen delivery (DO2CRIT), i.e., the hemoglobin concentration (Hgb) and oxygen delivery (DO2) at which oxygen consumption (VO2 independently measured by indirect calorimetry) was no longer sustained, and Hgb at the moment of death, defined prospectively as the point when VO2 decreased below 40 nil/min, were used to assess the tolerance of the two groups to progressive isovolemic anemia. Results: At hematocrits of 15% and 10% (Hgb, 47 and 31 g/l), VO2 was maintained in both groups by an increase (P &lt; 0.001) in cardiac output (CO) and extraction ratio (ER; P &lt; 0.001) with unchanged mean arterial lactate concentration (L-art.). At hematocrit of 7% (Hgb, 22 g/l), all normothermic but no hypothermic animals had DO2-dependent VO2. No normothermic and three hypothermic animals survived to 5% hematocrit (Hgb, 15 g/l), and none survived to 3%. Hgb(CRIT) was 23 +/- 2 g/l and 19 +/- 6 g/l (mean +/- SD) in normothermic and hypothermic animals, respectively (P = 0.053). Hgb at death was 19 +/- 3 g/l versus 14 +/- 4 g/l (P = 0.015), and DO2CRIT was 8.7 +/- 1.7 versus 4.6 +/- 0.8 ml.kg(-1).min(-1) (P &lt; 0.001). Conclusion: During progressive normovolemic hemodilution in pigs, hypothermia did not significantly change Hgb(CRIT), but it decreased the Hgb at death, i.e., short-term survival was prolonged.},
  author       = {Perez de Sá, Valéria and Roscher, Roger and Cunha Goncalves, Doris and Larsson, A and Werner, Olof},
  issn         = {1528-1175},
  language     = {eng},
  number       = {5},
  pages        = {1189--1197},
  publisher    = {Lippincott Williams & Wilkins},
  series       = {Anesthesiology},
  title        = {Mild hypothermia has minimal effects on the tolerance to severe progressive normovolemic anemia in swine},
  volume       = {97},
  year         = {2002},
}