Biomaterial Database

Changes in blood flow velocity in the middle cerebral artery during nonpulsatile hypothermic cardiopulmonary bypass. 1994

H Endoh, and K Shimoji

Department of Anesthesiology, Niigata City General Hospital, Japan.

OBJECTIVE We evaluated the utility of blood flow velocity measurements by transcranial Doppler ultrasonography as a tool to indirectly measure cerebral perfusion during cardiopulmonary bypass. METHODS We simultaneously measured blood flow velocity in the middle cerebral artery and physiological variables in 18 patients undergoing cardiac surgery under hypothermic cardiopulmonary bypass in which pH and PaCO2 were managed with the alpha-stat acid-base strategy. We expressed blood flow velocity as a relative value of control obtained under normothermia and normocarbia before bypass. We also developed an original index, modified cerebral metabolic rate for oxygen, to estimate cerebral metabolic rate for oxygen. RESULTS Relative velocity was significantly (P < .01) reduced during stable aortic cross-clamp compared with before bypass and was significantly (P < .01) increased during rewarming compared with at aortic cross-clamp. Modified cerebral metabolic rate for oxygen significantly correlated with nasopharyngeal temperature during cooling, aortic cross-clamp, and rewarming (r = .756, P < .0001; r = .4, P < .01; r = .725, P < .0005, respectively). Calculated temperature coefficient for modified cerebral metabolic rate of oxygen was 2.7 +/- 1.4 (mean +/- SD, n = 10) during cooling. Only nasopharyngeal temperature and PaCO2 were significant determinants of relative velocity during aortic cross-clamp. CONCLUSIONS We can monitor cerebral perfusion and metabolism by measurements of relative velocity and modified cerebral metabolic rate for oxygen during hypothermic cardiopulmonary bypass.

UI	MeSH Term	Description	Entries
D007036	Hypothermia, Induced	Abnormally low BODY TEMPERATURE that is intentionally induced in warm-blooded animals by artificial means. In humans, mild or moderate hypothermia has been used to reduce tissue damages, particularly after cardiac or spinal cord injuries and during subsequent surgeries.	Induced Hypothermia,Mild Hypothermia, Induced,Moderate Hypothermia, Induced,Targeted Temperature Management,Therapeutic Hypothermia,Hypothermia, Therapeutic,Induced Mild Hypothermia,Induced Mild Hypothermias,Induced Moderate Hypothermia,Induced Moderate Hypothermias,Mild Hypothermias, Induced,Moderate Hypothermias, Induced,Targeted Temperature Managements
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009131	Muscle, Smooth, Vascular	The nonstriated involuntary muscle tissue of blood vessels.	Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D011674	Pulse	The rhythmical expansion and contraction of an ARTERY produced by waves of pressure caused by the ejection of BLOOD from the left ventricle of the HEART as it contracts.	Pulses
D001783	Blood Flow Velocity	A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.	Blood Flow Velocities,Flow Velocities, Blood,Flow Velocity, Blood,Velocities, Blood Flow,Velocity, Blood Flow
D002315	Cardiopulmonary Bypass	Diversion of the flow of blood from the entrance of the right atrium directly to the aorta (or femoral artery) via an oxygenator thus bypassing both the heart and lungs.	Heart-Lung Bypass,Bypass, Cardiopulmonary,Bypass, Heart-Lung,Bypasses, Cardiopulmonary,Bypasses, Heart-Lung,Cardiopulmonary Bypasses,Heart Lung Bypass,Heart-Lung Bypasses
D002536	Cerebral Arteries	The arterial blood vessels supplying the CEREBRUM.	Arteries, Cerebral,Artery, Cerebral,Cerebral Artery
D005260	Female		Females