Cerebral vasoreactivity to carbon dioxide during cardiopulmonary perfusion at normothermia and hypothermia

Journal Article · Fri Dec 01 04:00:00 EST 1989 · Annals of Thoracic Surgery; (USA)

DOI:https://doi.org/10.1016/0003-4975(89)90668-1· OSTI ID:5028188

Johnsson, P; Messeter, K; Ryding, E; Kugelberg, J; Stahl, E ^[1]

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1. University Hospital, Lund (Sweden)

With the pH-stat acid-base regulation strategy during hypothermic cardiopulmonary bypass (CPB), carbon dioxide (CO{sub 2}) is generally administered to maintain the partial pressure of arterial CO{sub 2} at a higher level than with the alpha-stat method. With preserved CO{sub 2} vasoreactivity during CPB, this induction of respiratory acidosis can lead to a much higher cerebral blood flow level than is motivated metabolically. To evaluate CO{sub 2} vasoreactivity, cerebral blood flow was measured using a xenon 133 washout technique before, during, and after CPB at different CO{sub 2} levels in patients who were undergoing coronary artery bypass grafting with perfusion at either hypothermia or normothermia. The overall CO{sub 2} reactivity was 1.2 mL/100 g/min/mm Hg. There was no difference between the groups. The CO{sub 2} reactivity was not affected by temperature or CPB. The induced hemodilution resulted in higher cerebral blood flow levels during CPB, although this was counteracted by the temperature-dependent decrease in the hypothermia group. After CPB, a transient increase in cerebral blood flow was noted in the hypothermia group, the reason for which remains unclear. The study shows that manipulation of the CO{sub 2} level at different temperatures results in similar changes in cerebral blood flow irrespective of the estimated metabolic demand. This finding further elucidates the question of whether alpha-stat or pH-stat is the most physiological way to regulate the acid-base balance during hypothermic CPB.

• OSTI ID: 5028188
• Journal Information: Annals of Thoracic Surgery; (USA), Journal Name: Annals of Thoracic Surgery; (USA) Vol. 48:6; ISSN ATHSA; ISSN 0003-4975
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ARTERIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD FLOW
BLOOD VESSELS
BODY
BODY TEMPERATURE
BRAIN
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARDIOVASCULAR SYSTEM
CENTRAL NERVOUS SYSTEM
CHALCOGENIDES
CORONARIES
DAYS LIVING RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
HOMEOSTASIS
HYPOTHERMIA
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MEDICINE
METABOLISM
NERVOUS SYSTEM
NONMETALS
NUCLEI
ORGANS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PATIENTS
RADIOISOTOPES
SURGERY
TEMPERATURE DEPENDENCE
XENON 133
XENON ISOTOPES