Direct Cerebral Vasodilatory Effects of Sevoflurane and Isoflurane 

1999 ◽  
Vol 91 (3) ◽  
pp. 677-677 ◽  
Author(s):  
Basil F. Matta ◽  
Karen J. Heath ◽  
Kate Tipping ◽  
Andrew C. Summors
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
End Tidal

Background The effect of volatile anesthetics on cerebral blood flow depends on the balance between the indirect vasoconstrictive action secondary to flow-metabolism coupling and the agent's intrinsic vasodilatory action. This study compared the direct cerebral vasodilatory actions of 0.5 and 1.5 minimum alveolar concentration (MAC) sevoflurane and isoflurane during an propofol-induced isoelectric electroencephalogram. Methods Twenty patients aged 20-62 yr with American Society of Anesthesiologists physical status I or II requiring general anesthesia for routine spinal surgery were recruited. In addition to routine monitoring, a transcranial Doppler ultrasound was used to measure blood flow velocity in the middle cerebral artery, and an electroencephalograph to measure brain electrical activity. Anesthesia was induced with propofol 2.5 mg/kg, fentanyl 2 micro/g/kg, and atracurium 0.5 mg/kg, and a propofol infusion was used to achieve electroencephalographic isoelectricity. End-tidal carbon dioxide, blood pressure, and temperature were maintained constant throughout the study period. Cerebral blood flow velocity, mean blood pressure, and heart rate were recorded after 20 min of isoelectric encephalogram. Patients were then assigned to receive either age-adjusted 0.5 MAC (0.8-1%) or 1.5 MAC (2.4-3%) end-tidal sevoflurane; or age-adjusted 0.5 MAC (0.5-0.7%) or 1.5 MAC (1.5-2%) end-tidal isoflurane. After 15 min of unchanged end-tidal concentration, the variables were measured again. The concentration of the inhalational agent was increased or decreased as appropriate, and all measurements were repeated again. All measurements were performed before the start of surgery. An infusion of 0.01% phenylephrine was used as necessary to maintain mean arterial pressure at baseline levels. Results Although both agents increased blood flow velocity in the middle cerebral artery at 0.5 and 1.5 MAC, this increase was significantly less during sevoflurane anesthesia (4+/-3 and 17+/-3% at 0.5 and 1.5 MAC sevoflurane; 19+/-3 and 72+/-9% at 0.5 and 1.5 MAC isoflurane [mean +/- SD]; P<0.05). All patients required phenylephrine (100-300 microg) to maintain mean arterial pressure within 20% of baseline during 1.5 MAC anesthesia. Conclusions In common with other volatile anesthetic agents, sevoflurane has an intrinsic dose-dependent cerebral vasodilatory effect. However, this effect is less than that of isoflurane.

Slow oscillations in middle cerebral artery cerebral blood flow velocity and aging

2007 ◽  
Vol 29 (3) ◽  
pp. 260-263 ◽  
Author(s):  
Philip M. Lewis ◽  
Piotr Smielewski ◽  
John D. Pickard ◽  
Marek Czosnyka
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Slow Oscillations

Middle cerebral artery flow velocity and pulse pressure during dynamic exercise in humans

2005 ◽  
Vol 288 (4) ◽  
pp. H1526-H1531 ◽  
Author(s):  
Shigehiko Ogoh ◽  
Paul J. Fadel ◽  
Rong Zhang ◽  
Christian Selmer ◽  
Øivind Jans ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Transfer Function ◽  
Arterial Pressure ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Pulse Pressure ◽  
Heavy Exercise ◽  
Transfer Function Analysis

Exercise challenges cerebral autoregulation (CA) by a large increase in pulse pressure (PP) that may make systolic pressure exceed what is normally considered the upper range of CA. This study examined the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) and systolic ( Vs), diastolic ( Vd). and mean ( Vm) middle cerebral artery (MCA) blood flow velocity during mild, moderate, and heavy cycling exercise. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated using transfer function analysis. PP increased by 37% and 57% during moderate and heavy exercise, respectively ( P < 0.05), and the pulsatility of MCA V increased markedly. Thus exercise increased MCA Vm and Vs ( P < 0.05) but tended to decrease MCA Vd ( P = 0.06). However, the normalized low-frequency transfer function gain between MAP and MCA Vm and between SBP and MCA Vs remained unchanged from rest to exercise, whereas that between DBP and MCA Vd increased from rest to heavy exercise ( P < 0.05). These findings suggest that during exercise, CA is challenged by a rapid decrease rather than by a rapid increase in blood pressure. However, dynamic CA remains able to modulate blood flow around the exercise-induced increase in MCA Vm, even during high-intensity exercise.

scholarly journals Blood Flow Velocity Changes in the Middle Cerebral Artery Induced by Driving Fatigue

2011 ◽  
Vol 2-3 ◽  
pp. 219-222
Author(s):  
Hong Wang ◽  
Xiao Mei Chi ◽  
Ya Jing Yan ◽  
Ning Ning Zhang
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Driving Fatigue ◽  
Velocity Changes ◽  
Fatigue Driving

The cerebral blood flow velocity (CBFV) of middle cerebral artery (MCA) was detected during the fatigue driving using Transcranial Doppler. The CBFV was also analyzed after the fatigue driving by different means of relaxation to alleviate brain fatigue. The results show that the CBFV in MCA is reduced by driving fatigue.

Multimodal Quantitation of the Effects of Endovascular Therapy for Vasospasm on Cerebral Blood Flow, Transcranial Doppler Ultrasonographic Velocities, and Cerebral Artery Diameters

Neurosurgery ◽  
2002 ◽  
Vol 51 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Rod J. Oskouian ◽  
Neil A. Martin ◽  
Jae Hong Lee ◽  
Thomas C. Glenn ◽  
Donald Guthrie ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Endovascular Therapy ◽  
Balloon Angioplasty ◽  
Transcranial Doppler ◽  
Blood Flow Velocity ◽  
Artery Blood Flow

Abstract OBJECTIVE The goal of this study was to quantify the effects of endovascular therapy on vasospastic cerebral vessels. METHODS We reviewed the medical records for 387 patients with ruptured intracranial aneurysms who were treated at a single institution (University of California, Los Angeles) between May 1, 1993, and March 31, 2001. Patients who developed cerebral vasospasm and underwent cerebral arteriographic, transcranial Doppler ultrasonographic, and cerebral blood flow (CBF) studies before and after endovascular therapy for cerebral arterial spasm (vasospasm) were included in this study. RESULTS Forty-five patients fulfilled the aforementioned criteria and were treated with either papaverine infusion, papaverine infusion with angioplasty, or angioplasty alone. After balloon angioplasty (12 patients), CBF increased from 27.8 ± 2.8 ml/100 g/min to 28.4 ± 3.0 ml/100 g/min (P = 0.87); the middle cerebral artery blood flow velocity was 157.6 ± 9.4 cm/s and decreased to 76.3 ± 9.3 cm/s (P &lt; 0.05), with a mean increase in cerebral artery diameters of 24.4%. Papaverine infusion (20 patients) transiently increased the CBF from 27.5 ± 2.1 ml/100 g/min to 38.7 ± 2.8 ml/100 g/min (P &lt; 0.05) and decreased the middle cerebral artery blood flow velocity from 109.9 ± 9.1 cm/s to 82.8 ± 8.6 cm/s (P &lt; 0.05). There was a mean increase in vessel diameters of 30.1% after papaverine infusion. Combined treatment (13 patients) significantly increased the CBF from 33.3 ± 3.2 ml/100 g/min to 41.7 ± 2.8 ml/100 g/min (P &lt; 0.05) and decreased the transcranial Doppler velocities from 148.9 ± 12.7 cm/s to 111.4 ± 10.6 cm/s (P &lt; 0.05), with a mean increase in vessel diameters of 42.2%. CONCLUSION Balloon angioplasty increased proximal vessel diameters, whereas papaverine treatment effectively dilated distal cerebral vessels. In our small series, we observed no correlation between early clinical improvement or clinical outcomes and any of our quantitative or physiological data (CBF, transcranial Doppler velocities, or vessel diameters).

Disassociation of static and dynamic cerebral autoregulatory performance in healthy volunteers after lipopolysaccharide infusion and in patients with sepsis

2012 ◽  
Vol 303 (11) ◽  
pp. R1127-R1135 ◽  
Author(s):  
Ronan M. G. Berg ◽  
Ronni R. Plovsing ◽  
Andreas Ronit ◽  
Damian M. Bailey ◽  
Niels-Henrik Holstein-Rathlou ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Middle Cerebral Artery ◽  
Healthy Volunteers ◽  
Flow Velocity ◽  
Phase Difference ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Cerebral Autoregulation ◽  
Artery Blood Flow

Sepsis is frequently complicated by brain dysfunction, which may be associated with disturbances in cerebral autoregulation, rendering the brain susceptible to hypoperfusion and hyperperfusion. The purpose of the present study was to assess static and dynamic cerebral autoregulation 1) in a human experimental model of the systemic inflammatory response during early sepsis and 2) in patients with advanced sepsis. Cerebral autoregulation was tested using transcranial Doppler ultrasound in healthy volunteers ( n = 9) before and after LPS infusion and in patients with sepsis ( n = 16). Static autoregulation was tested by norepinephrine infusion and dynamic autoregulation by transfer function analysis (TFA) of spontaneous oscillations between mean arterial blood pressure and middle cerebral artery blood flow velocity in the low frequency range (0.07–0.20 Hz). Static autoregulatory performance after LPS infusion and in patients with sepsis was similar to values in healthy volunteers at baseline. In contrast, TFA showed decreased gain and an increased phase difference between blood pressure and middle cerebral artery blood flow velocity after LPS (both P < 0.01 vs. baseline); patients exhibited similar gain but lower phase difference values ( P < 0.01 vs. baseline and LPS), indicating a slower dynamic autoregulatory response. Our findings imply that static and dynamic cerebral autoregulatory performance may disassociate in sepsis; thus static autoregulation was maintained both after LPS and in patients with sepsis, whereas dynamic autoregulation was enhanced after LPS and impaired with a prolonged response time in patients. Hence, acute surges in blood pressure may adversely affect cerebral perfusion in patients with sepsis.

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