Extreme hemodilution: Effects of inhalation anesthetics, hypoxia, and blood loss. An Experimental study in pigs.
(1997)- Abstract
- Hemodilution reduces the need for blood transfusion and hereby the risk for transmission of infectious agents. The present study investigated effects on systemic and myocardial circulation and oxygenation, and blood lactate concentrations; induced by nitrous oxide, isoflurane, hypoxia, and uncompensated blood loss, in pigs hemodiluted to a hematocrit of 11%. In addition, indicators of hypovolemia and insufficient oxygen delivery, as well as the correlation between mixed and central venous blood oxygen were studied. It was found that nitrous oxide had insignificant circulatory effects, but oxygen delivery decreased during isoflurane administration, hypoxia or uncompensated blood loss, and delivery dependent oxygen uptake and hyperlactemia... (More)
- Hemodilution reduces the need for blood transfusion and hereby the risk for transmission of infectious agents. The present study investigated effects on systemic and myocardial circulation and oxygenation, and blood lactate concentrations; induced by nitrous oxide, isoflurane, hypoxia, and uncompensated blood loss, in pigs hemodiluted to a hematocrit of 11%. In addition, indicators of hypovolemia and insufficient oxygen delivery, as well as the correlation between mixed and central venous blood oxygen were studied. It was found that nitrous oxide had insignificant circulatory effects, but oxygen delivery decreased during isoflurane administration, hypoxia or uncompensated blood loss, and delivery dependent oxygen uptake and hyperlactemia was observed when systemic oxygen delivery decreased below 10 ml x kg-1 x min-1. The heart was more tolerant to the reduced oxygen delivery than were other organs, when judged by arterial lactate concentration and myocardial lactate uptake. The decrease in mixed venous oxygen saturation and systemic oxygen delivery correlated well with the increase in arterial lactate concentration. There was a close relation between central and mixed venous oxygen saturation. A decrease in arterial blood pressure was the first sign of hypovolemia during hemodilution, wheras central venous and pulmonary capillary wedge pressures were insensitive indicators of hypovolemia. It is concluded that the risk of compromising cardiovascular function and inducing severe tissue hypoxia is high during extreme acute normovolemic hemodilution. Nevertheless our findings suggest that in young individuals a hematocrit as low as 11% can be accepted temporarily providing adequate monitoring is available, and if caution is taken to avoid further decrease in systemic oxygen delivery. (Less)
- Abstract (Swedish)
- Popular Abstract in Swedish
Effekter av narkosgas, låg syrgashalt och blodförlust under blodspädning (hemodilution) på sövda grisar. Blodspädning (hemodilution) används under operation för att minska behovet av blodtransfusion med dess inneboende risker. Hemodilution innebär att blod tappas före operationsstart och ersätts med en blodkroppsfri lösning. Om en blödning uppstår under operationen blir förlusten av röda blodkroppar mindre och det tappade blodet kan sedan ges tillbaka efter att ingreppet avslutats. En annan typ av hemodilution, som används i stort sett vid alla operationer, innebär att en blodförlust inte ersätts med blod, utan med blodkroppsfri vätskelösning. Hemodilution gör att blodvärdet (hematokriten) och... (More) - Popular Abstract in Swedish
Effekter av narkosgas, låg syrgashalt och blodförlust under blodspädning (hemodilution) på sövda grisar. Blodspädning (hemodilution) används under operation för att minska behovet av blodtransfusion med dess inneboende risker. Hemodilution innebär att blod tappas före operationsstart och ersätts med en blodkroppsfri lösning. Om en blödning uppstår under operationen blir förlusten av röda blodkroppar mindre och det tappade blodet kan sedan ges tillbaka efter att ingreppet avslutats. En annan typ av hemodilution, som används i stort sett vid alla operationer, innebär att en blodförlust inte ersätts med blod, utan med blodkroppsfri vätskelösning. Hemodilution gör att blodvärdet (hematokriten) och antalet röda blodkroppar minskar. Eftersom de röda blodkropparna innehåller syrgas, minskar syrgashalten i blodet och tillförseln av syrgas till vävnaderna kan försämras. Kroppen försöker att kompensera detta genom att öka hjärtats pumpning av blod, samt i vävnaderna suga ut mer syrgas från de röda blodkropparna. Kompensationsmöjligheten vid försämrad hjärtfunktion, minskning av blodkropparnas syrgashalt eller minskning av blodvolymen - som ytterligare minskar syrgastillförseln - blir dock reducerad och risk för allvarlig syrgasbrist i vävnaderna kan då uppstå. Vid operationer där hemodilution används sövs patienterna ofta med narkosgaser som kan påverka hjärtat. Vid operation finns dessutom alltid risk för att syrgashalten i blodet sjunker och att blodförluster inte ersätts tillräckligt. I denna vanlig narkosgaser (lustgas och isofluran), låg syrgashalt i blodet (hypoxi) samt av icke ersatt blodförlust hos extremt blodspädda grisar där hematokritvärdet sänktes från 33% till 11%. Dessutom undersöktes vilka parametrar som är av störst nytta för övervakning av hjärtfunktionen vid hemodilution. Studien visade att lustgas påverkade hjärta och kretslopp mycket lindrigt vid hemodilution. Däremot minskade isofluran, hypoxi och blodförlust syrgastillförseln till vävnaderna markant, vilket gjorde att mjölksyra började produceras. Hjärtat tolererade den minskade syrgastillförseln bättre än andra organ. Dett fanns ett klart samband mellan sjunkande syrgashalt i venblod och den ökande mjölksyraproduktionen. Blodtryckssänkning var det första tecknet på låg blodvolym vid blodförlust, medan däremot förändring av ventrycket var relativt ospecifik. Extrem blodspädning kan troligtvis tolereras under en kortare tid hos yngre individer, men noggranna kontroller av hjärtfunktionen, blodtryck och blodets syrgashalt är absolut nödvändiga för att undvika risker för en ytterligare försämring av syrgastillförseln. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/29306
- author
- Schou, Henning LU
- supervisor
- opponent
-
- Ph.D. Winsö, Ola, Department of Anesthesiology, University of Gothenburg, Sweden
- organization
- publishing date
- 1997
- type
- Thesis
- publication status
- published
- subject
- keywords
- Anaesthesiology, oxygen saturation., blood volume, coronary circulation, blood lactate, oxygen uptake, Anemia, oxygen delivery, intensive care, Anestesiologi, intensivvård
- pages
- 112 pages
- publisher
- Department of Anaesthesiology and Intensive Care, Lund
- defense location
- University Hospital, Lund
- defense date
- 1997-05-24 10:15:00
- external identifiers
-
- other:ISRN: LUMEW/MEAN-1044-SE
- ISBN
- 91-628-2488-0
- language
- English
- LU publication?
- yes
- id
- c134e154-c973-4896-8faa-889ec2c0cdce (old id 29306)
- date added to LUP
- 2016-04-04 11:31:35
- date last changed
- 2018-11-21 21:05:25
@phdthesis{c134e154-c973-4896-8faa-889ec2c0cdce,
abstract = {{Hemodilution reduces the need for blood transfusion and hereby the risk for transmission of infectious agents. The present study investigated effects on systemic and myocardial circulation and oxygenation, and blood lactate concentrations; induced by nitrous oxide, isoflurane, hypoxia, and uncompensated blood loss, in pigs hemodiluted to a hematocrit of 11%. In addition, indicators of hypovolemia and insufficient oxygen delivery, as well as the correlation between mixed and central venous blood oxygen were studied. It was found that nitrous oxide had insignificant circulatory effects, but oxygen delivery decreased during isoflurane administration, hypoxia or uncompensated blood loss, and delivery dependent oxygen uptake and hyperlactemia was observed when systemic oxygen delivery decreased below 10 ml x kg-1 x min-1. The heart was more tolerant to the reduced oxygen delivery than were other organs, when judged by arterial lactate concentration and myocardial lactate uptake. The decrease in mixed venous oxygen saturation and systemic oxygen delivery correlated well with the increase in arterial lactate concentration. There was a close relation between central and mixed venous oxygen saturation. A decrease in arterial blood pressure was the first sign of hypovolemia during hemodilution, wheras central venous and pulmonary capillary wedge pressures were insensitive indicators of hypovolemia. It is concluded that the risk of compromising cardiovascular function and inducing severe tissue hypoxia is high during extreme acute normovolemic hemodilution. Nevertheless our findings suggest that in young individuals a hematocrit as low as 11% can be accepted temporarily providing adequate monitoring is available, and if caution is taken to avoid further decrease in systemic oxygen delivery.}},
author = {{Schou, Henning}},
isbn = {{91-628-2488-0}},
keywords = {{Anaesthesiology; oxygen saturation.; blood volume; coronary circulation; blood lactate; oxygen uptake; Anemia; oxygen delivery; intensive care; Anestesiologi; intensivvård}},
language = {{eng}},
publisher = {{Department of Anaesthesiology and Intensive Care, Lund}},
school = {{Lund University}},
title = {{Extreme hemodilution: Effects of inhalation anesthetics, hypoxia, and blood loss. An Experimental study in pigs.}},
year = {{1997}},
}