scholarly journals Local Cerebral Blood Flow and the Electrocorticogram during Sodium Nitroprusside Hypotension

1978 ◽  
Vol 6 (4) ◽  
pp. 290-296 ◽  
Author(s):  
C. L. Miller ◽  
D. G. Lampard ◽  
R. I. Griffiths ◽  
W. A. Brown
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Sodium Nitroprusside ◽  
Large Range ◽  
Local Cerebral Blood Flow ◽  
Hydrogen Electrode ◽  
Electrode Technique

Changes in local cerebral blood flow during sodium nitroprusside hypotension were measured using the hydrogen electrode technique. At mean arterial pressures from 90% to 50% of control values, local cerebral blood flow showed a significant decrease by 20%. When blood pressure was reduced below 50%, the local cerebral blood flow increased significantly and approached control levels. It is suggested that the flow increase may be due to local hypoxia. Associated with this increase were electrocorticogram changes indicative of hypoxia. The significant decrease in mean local cerebral blood flow and the large range of flows seen during mild hypotension indicate that autoregulation is impaired. During hypotension, intracranial pressure increased by, at most, 3 mm Hg. Cardiac output was usually unaffected and was never decreased by more than 20%.

Cerebral blood flow and evoked potentials during Cushing response in sheep

1989 ◽  
Vol 256 (3) ◽  
pp. H779-H788
Author(s):  
R. C. Koehler ◽  
J. E. Backofen ◽  
R. W. McPherson ◽  
M. D. Jones ◽  
M. C. Rogers ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Arterial Pressure ◽  
Evoked Potentials ◽  
Aortic Pressure ◽  
Base Line ◽  
Auditory Evoked Responses ◽  
Cushing Response

We determined how alterations in systemic hemodynamics, characteristic of the Cushing response, are related to changes in cerebral blood flow (CBF), cerebral metabolic rate of O2 (CMRO2), and brain electrical conductive function, as assessed by somatosensory-evoked potentials (SEP) and brain stem auditory-evoked responses (BAER). In three groups of eight pentobarbital-anesthetized sheep, intracranial pressure was gradually elevated to within 50, 25, or 0 mmHg of base-line mean arterial pressure and then held constant for 40 min by intraventricular infusion of mock cerebrospinal fluid. Microsphere-determined CBF fell when cerebral perfusion pressure was less than 50 mmHg. CMRO2 fell when CBF fell greater than 30-40%. Mean aortic pressure and cardiac output increased when CBF fell greater than 40%, i.e., at approximately the level at which CMRO2 fell. Furthermore, the magnitude of the increase in arterial pressure and cardiac output correlated with the reduction of CMRO2. SEP latency did not increase unless CBF fell greater than 55-65%, corresponding to a 20-30% reduction of CMRO2. Increased latency of BAER wave V was associated with a fall in midbrain blood flow of greater than 65-70%. Thus increase in SEP and BAER latencies required reductions of flow greater than those required to elicit a systemic response. This demonstrates that there is a range of intracranial pressure over which the increase in arterial pressure preserves sufficient CBF to sustain minimal electrical conductive function. The best predictor of the onset and magnitude of the Cushing response in adult sheep is the decrease in CMRO2.

Suctioning and Cerebral Blood Flow

PEDIATRICS ◽  
1984 ◽  
Vol 73 (5) ◽  
pp. 737-737
Author(s):  
JEFFREY M. PERLMAN ◽  
JOSEPH J. VOLPE
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Flow Velocity ◽  
Arterial Blood Pressure ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Base Line ◽  
Arterial Blood

In Reply.— Marshall misread a critical piece of information in the text. His interpretation of the data would be correct, if the intracranial pressure, arterial blood pressure, and cerebral blood flow velocity changes occurred simultaneously. However, as we stated in the text (see section on "Temporal Features of Changes with Suctioning"), the intracranial pressure fell to base-line values immediately following suctioning, whereas the changes in arterial blood pressure and cerebral blood flow velocity occurred more slowly over an approximately two-minute period.

scholarly journals Non-invasive evaluation of cerebral hemodynamic and intracranial pressure in pediatric neuroinfections

2018 ◽  
Vol 9 (4) ◽  
pp. 485-490
Author(s):  
М. А. Georgiynts ◽  
V. А. Коrsunov ◽  
О. М. Оlkhovska ◽  
К. E. Stoliarov
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Intensive Care ◽  
Intracranial Pressure ◽  
Cerebral Perfusion ◽  
Flow Index ◽  
Non Invasive ◽  
Group I ◽  
Group Ii

The study of intracranial pressure (eICP), cerebral perfusion pressure (eCPP), cerebral blood flow index (CFI), zero flow pressure (ZFP) in 49 children hospitalized in the intensive care unit with severe course of neuroinfections was carried out. The level of consciousness was determined by the Glasgow pediatric scale. Monitoring of central and peripheral hemodynamics (ECG, heart rate, systolic, diastolic and mean blood pressure, and cardiac output), pulse oximetry, capnography, hemoglobin, hematocrit, total protein, urea, creatinine, lactate, glucose and serum electrolytes was done. An ultrasound scanner was used to perform ultrasound duplex scanning of blood flow in the left and middle cerebral artery (MCA), measuring maximum, minimum and average blood flow velocities, pulsation index (PI), and resistance index (RI). Based on the formulae of Edouard et al. indicators of eCPP, ZFP, CFI, eICP were calculated. The eSCP was also determined by the formulae of Kligenchöfer et al. and Bellner et al. All patients were divided into group I with RI > 1.3 and group II with RI < 1.3. It was found that eCPP in the group I was significantly less (29.5 ± 1.3 mm Hg) than in the II group (41.6 ± 1.7 mm Hg). Despite the lack of a reliable difference in blood pressure between groups I and II, the difference in eCPP was found due to a significant difference in eICP 34.6 ± 1.4 and 27.6 ± 0.89 mm Hg in I and II groups respectively. ZFP in group I was significantly higher than in group II. The indexes of the Glasgow coma scale was significantly lower in group I and 7.8 ± 0.6 points. There were observed direct moderate correlations between systolic blood pressure, cardiac output and eSRP and CFI, presumably associated with a loss of autoregulation. CFI in the group I was lower than in the group II. Thus, non-invasive examination of cerebral flow in MCA by duplex sonography revealed that PI > 1.3 is an informative marker of intracranial hypertension and reduction of cerebral perfusion, which is common in children with neuroinfections. To determine the eSRP and CFI it is advisable to use the formula of Edouard et al. and to determine the eICP the formula of Kligenchöfer et al. The obtained data can be useful for objectifying the severity of the condition, predicting the outcomes of neuroinfections, choosing the directions of intensive care and evaluating its effectiveness.

Influence of blood pressure and cardiac output on cerebral blood flow and autoregulation in acute stroke measured by TCD

1996 ◽  
Vol 3 (6) ◽  
pp. 539-543 ◽  
Author(s):  
J. Treib ◽  
A. Haass ◽  
D. Koch ◽  
M.T. Grauer ◽  
M. Stoll ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Cerebral Blood Flow ◽  
Acute Stroke
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