Brain hyperperfusion during cardiac operations. Cerebral blood flow measured in man by intra-arterial injection of xenon 133: evidence suggestive of intraoperative microembolism
Cerebral blood flow (CBF) was measured by intra-arterial injection of xenon 133 in 29 patients during cardiac operations. Marked changes occurred in all patients. A normal and significant correlation with temperature and plasma pCO/sub 2/ (p less than 0.01) support the reliability of the method. Mean CBF measured between sternotomy and the onset of extracorporeal circulation (ECC) was 38 ml/100 gm . min. The first minute of ECC was associated with a decrease in CBF in nine of 12 patients (p less than 0.02). During steady-state hypothermic ECC (temperature 29 degrees C), CBF increased unexpectedly to 64 ml/100 gm . min (p less than 0.01). Following rewarming steady-state normothermic ECC, mean CBF decreased to 42 ml/100 gm . min with signs of impairment of cerebral autoregulation. Ten and 20 minutes after termination of ECC, mean CBF was 40 and 41 ml/100 gm . min, respectively. Arterial PCO2 was found to be important in regulating CBF. The cerebral autoregulation maintained CBF down to arterial pressures of around 55 mm Hg. Below this level, CBF was significantly correlated with perfusion pressure (p less than 0.01). Multiple small emboli with a hyperemic border zone could cause a brain hyperperfusion, as seen in our patients during bypass. Measurements of CBF during ECC hold promise as a guide toward safer cardiac operations.
- Research Organization:
- Rigshospitalet, State University Hospital, Copenhagen, Denmark
- OSTI ID:
- 5477826
- Journal Information:
- J. Thorac. Cardiovasc. Surg.; (United States), Vol. 86:2
- Country of Publication:
- United States
- Language:
- English
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BRAIN
BLOOD FLOW
BLOOD PLASMA
BLOOD PRESSURE
CARBON DIOXIDE
EMBOLI
HEART
HYPOTHERMIA
MEASURING METHODS
PATIENTS
RADIOISOTOPE SCANNING
SURGERY
TEMPERATURE DEPENDENCE
XENON 133
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BODY
BODY FLUIDS
BODY TEMPERATURE
CARBON COMPOUNDS
CARBON OXIDES
CARDIOVASCULAR SYSTEM
CENTRAL NERVOUS SYSTEM
CHALCOGENIDES
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MATERIALS
MEDICINE
NERVOUS SYSTEM
NUCLEI
ORGANS
OXIDES
OXYGEN COMPOUNDS
RADIOISOTOPES
XENON ISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics