Overestimation of intrathoracic blood volume in a patient with atrial fibrillation and subsequent severely reduced atrial blood-flow

Abstract Background Rapid fluid infusion resulting in increased hepatic blood flow may decrease the propofol plasma concentration (Cp) because propofol is a high hepatic extraction drug. The authors investigated the effects of rapid colloid and crystalloid infusions on the propofol Cp during target-controlled infusion. Methods Thirty-six patients were randomly assigned to 1 of 3 interventions (12 patients per group). At least 30 min after the start of propofol infusion, patients received either a 6% hydroxyethyl starch (HES) solution at 24 ml·kg−1·h−1 or acetated Ringer’s solution at 24 or 2 ml·kg−1·h−1 during the first 20 min. In all groups, acetated Ringer’s solution was infused at 2 ml·kg−1·h−1 during the next 20 min. The propofol Cp was measured every 2.5 min as the primary outcome. Cardiac output, blood volume, and indocyanine green disappearance rate were determined using a pulse dye densitogram analyzer before and after the start of fluid administration. Effective hepatic blood flow was calculated as the blood volume multiplied by the indocyanine green disappearance rate. Results The rapid HES infusion significantly decreased the propofol Cp by 22 to 37%, compared to the Cp at 0 min, whereas the rapid or maintenance infusion of acetate Ringer’s solution did not decrease the propofol Cp. Rapid HES infusion, but not acetate Ringer’s solution infusion, increased the effective hepatic blood flow. Conclusions Rapid HES infusion increased the effective hepatic blood flow, resulting in a decreased propofol Cp during target-controlled infusion. Rapid HES infusion should be used cautiously as it may decrease the depth of anesthesia.

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Effects of Acetazolamide on Cerebral Blood Flow, Blood Volume, and Oxygen Metabolism: A Positron Emission Tomography Study with Healthy Volunteers

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/00004647-200112000-00012 ◽

2001 ◽

Vol 21 (12) ◽

pp. 1472-1479 ◽

Cited By ~ 73

Author(s):

Hidehiko Okazawa ◽

Hiroshi Yamauchi ◽

Kanji Sugimoto ◽

Hiroshi Toyoda ◽

Yoshihiko Kishibe ◽

...

Keyword(s):

Positron Emission Tomography ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Metabolic Rate ◽

Blood Volume ◽

Cerebral Blood Volume ◽

Capillary Blood ◽

Emission Tomography ◽

Positron Emission ◽

Capillary Blood Volume

To evaluate changes in cerebral hemodynamics and metabolism induced by acetazolamide in healthy subjects, positron emission tomography studies for measurement of cerebral perfusion and oxygen consumption were performed. Sixteen healthy volunteers underwent positron emission tomography studies with15O-gas and water before and after intravenous administration of acetazolamide. Dynamic positron emission tomography data were acquired after bolus injection of H215O and bolus inhalation of15O2. Cerebral blood flow, metabolic rate of oxygen, and arterial-to-capillary blood volume images were calculated using the three-weighted integral method. The images of cerebral blood volume were calculated using the bolus inhalation technique of C15O. The scans for cerebral blood flow and volume and metabolic rate of oxygen after acetazolamide challenge were performed at 10, 20, and 30 minutes after drug injection. The parametric images obtained under the two conditions at baseline and after acetazolamide administration were compared. The global and regional values for cerebral blood flow and volume and arterial-to-capillary blood volume increased significantly after acetazolamide administration compared with the baseline condition, whereas no difference in metabolic rate of oxygen was observed. Acetazolamide-induced increases in both blood flow and volume in the normal brain occurred as a vasodilatory reaction of functioning vessels. The increase in arterial-to-capillary blood volume made the major contribution to the cerebral blood volume increase, indicating that the raise in cerebral blood flow during the acetazolamide challenge is closely related to arterial-to-capillary vasomotor responsiveness.

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Electromechanical Control of Atrium Function

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-204244 ◽

2009 ◽

Cited By ~ 1

Author(s):

Miroslava Svobodova ◽

Elena S. Di Martino

Keyword(s):

Atrial Fibrillation ◽

Blood Flow ◽

Cardiac Function ◽

The Body ◽

Pump Function ◽

Physical Systems ◽

Electrical Systems ◽

Mechanical Pump

The heart is a very efficient mechanical pump whose function is to controls the blood flow in the body. Two physical systems, namely mechanical for the pumping action and electrical for the control interact within the heart. Cardiac function can only be studied if both mechanical and electrical systems are considered. In particular, we are interested in the electromechanical control of the atrium pump function which is less studied then the electromechanical control of the ventricle pump function and none the less is a crucial factor in the development of atrial fibrillation.

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Effects of subarachnoid hemorrhage on cerebral blood volume, blood flow, and oxygen utilization in humans

Journal of Neurosurgery ◽

10.3171/jns.1977.46.4.0446 ◽

1977 ◽

Vol 46 (4) ◽

pp. 446-453 ◽

Cited By ~ 305

Author(s):

Robert L. Grubb ◽

Marcus E. Raichle ◽

John O. Eichling ◽

Mokhtar H. Gado

Keyword(s):

Blood Flow ◽

Subarachnoid Hemorrhage ◽

Blood Volume ◽

Cerebral Vasospasm ◽

Cerebral Blood Volume ◽

Neurological Deficits ◽

Regional Cerebral Blood ◽

Oxygen Utilization ◽

Ruptured Intracranial Aneurysm ◽

Regional Cerebral Blood Volume

✓ Forty-five studies of regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and regional cerebral oxygen utilization (rCMRO2) were performed in 30 patients undergoing diagnostic cerebral angiography for evaluation of a subarachnoid hemorrhage due to a ruptured intracranial aneurysm. Tracer methods employing radioactive oxygen-15 were used to measure rCBV, rCBF, and rCMRO2. The patient studies were divided into groups based on their neurological status and the presence or absence of cerebral vasospasm. Subarachnoid hemorrhage, with and without vasospasm, produced significant decreases in CBF and CMRO2. In general, patients with more severe neurological deficits, and patients with more severe degrees of vasospasm, had a more marked depression of CBF and CMRO2. The most striking finding was a significant (p < 0.001) increase in CBV (to 58% above normal) in patients with severe neurological deficits associated with severe cerebral vasospasm. This large increase suggests that cerebral vasospasm consists of constriction of the large, radiographically visible extraparenchymal vessels accompanied by a massive dilation of intraparenchymal vessels.

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