scholarly journals Analysis of the causes of age-related decline in the velocity of cerebral blood flow

2016 ◽  
Vol 15 (2) ◽  
pp. 45-50
Author(s):  
V. A. Schurov
Keyword(s):  
Blood Flow ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Cerebral Autoregulation ◽  
Lower Limbs ◽  
Functional Test ◽  
Muscle Sample ◽  
Age Related

Goal. Determining the causes of age-related decrease of blood flow velocity (BFV) in the middle cerebral artery (MCA) in healthy subjects and in patients during surgical lengthening of stunted limbs. Methods. BFV in MCA was determined by transcranial Doppler. The analysis of the indicator in functional muscle sample of 30 healthy people 18-60 years old and 30 patients 3-62 years of lagging in the growth of one of the lower limbs in the course of its operational extension. As an indicator of cerebral autoregulation used swing changes BFV indicators during the second holding muscle functional test. Results. The age-related reduction in flow rate in the middle cerebral artery was more pronounced in patients with disorders of the musculoskeletal system. At the same time, the average value of the magnitude of blood flow velocity index changes during the functional test in healthy individuals older than 10 years, as well as in patients before treatment and during the fixation is stable (17-25 %). Conclusion. Age-related decline in the BFV at MCA is a prerequisite for the preservation of cerebral autoregulation. Disorders of cerebral autoregulation in patients undergoing distraction of limbs greatly reduces their tolerance to physical exercise.

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.

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&lt;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.

scholarly journals Dynamic Regulation of Middle Cerebral Artery Blood Flow Velocity in Aging and Hypertension

Stroke ◽  
2000 ◽  
Vol 31 (8) ◽  
pp. 1897-1903 ◽  
Author(s):  
Lewis A. Lipsitz ◽  
Seiji Mukai ◽  
Jason Hamner ◽  
Margaret Gagnon ◽  
Viken Babikian
Keyword(s):  
Blood Flow ◽  
Middle Cerebral Artery ◽  
Flow Velocity ◽  
Cerebral Artery ◽  
Blood Flow Velocity ◽  
Artery Blood Flow ◽  
Dynamic Regulation
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