scholarly journals Quantifying the contribution of intracranial pressure and arterial blood pressure to spontaneous tympanic membrane displacement

2018 ◽  
Vol 39 (8) ◽  
pp. 085002
Author(s):  
Wahbi K El-Bouri ◽  
Dario Vignali ◽  
Konstantina Iliadi ◽  
Diederik Bulters ◽  
Robert J Marchbanks ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Intracranial Pressure ◽  
Tympanic Membrane ◽  
Arterial Blood Pressure ◽  
Arterial Blood ◽  
Membrane Displacement

The relationship of blood flow velocity fluctuations to intracranial pressure B waves

1992 ◽  
Vol 76 (3) ◽  
pp. 415-421 ◽  
Author(s):  
David W. Newell ◽  
Rune Aaslid ◽  
Renate Stooss ◽  
Hans J. Reulen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Intracranial Pressure ◽  
Arterial Blood Pressure ◽  
Wave Amplitude ◽  
Transcranial Doppler Ultrasound ◽  
Normal Subjects ◽  
Content Type ◽  
Arterial Blood ◽  
Flow Fluctuations

✓ Intracranial pressure (ICP) and continuous transcranial Doppler ultrasound signals were monitored in 20 head-injured patients and simultaneous synchronous fluctuations of middle cerebral artery (MCA) velocity and B waves of the ICP were observed. Continuous simultaneous monitoring of MCA velocity, ICP, arterial blood pressure, and expired CO2 revealed that both velocity waves and B waves occurred despite a constant CO2 concentration in ventilated patients and were usually not accompanied by fluctuations in the arterial blood pressure. Additional recordings from the extracranial carotid artery during the ICP B waves revealed similar synchronous fluctuations in the velocity of this artery, strongly supporting the hypothesis that blood flow fluctuations produce the velocity waves. The ratio between ICP wave amplitude and velocity wave amplitude was highly correlated to the ICP (r = 0.81, p < 0.001). Velocity waves of similar characteristics and frequency, but usually of shorter duration, were observed in seven of 10 normal subjects in whom MCA velocity was recorded for 1 hour. The findings in this report strongly suggest that B waves in the ICP are a secondary effect of vasomotor waves, producing cerebral blood flow fluctuations that become amplified in the ICP tracing, in states of reduced intracranial compliance.

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.

Responses of cerebral arterioles to increased venous pressure

1982 ◽  
Vol 243 (3) ◽  
pp. H442-H447 ◽  
Author(s):  
E. P. Wei ◽  
H. A. Kontos
Keyword(s):  
Blood Pressure ◽  
Intracranial Pressure ◽  
Arterial Blood Pressure ◽  
Venous Pressure ◽  
Venous Hypertension ◽  
Arterial Hypotension ◽  
Arterial Blood ◽  
Pial Arterioles ◽  
Cerebral Arterioles ◽  
Arteriolar Vasodilation

The responses of pial arterioles to increased venous pressure were studied in anesthetized cats equipped with cranial windows for the observation of the pial microcirculation. Stable increases in venous pressure consistently induced arteriolar vasodilation, which averaged 6-12% of the control diameter. The vasodilation occurred when arterial blood pressure was normal and during arterial hypotension induced by bleeding; it also occurred irrespective of whether intracranial pressure was kept constant or was allowed to increase venous hypertension. The results are consistent with the view that autoregulatory adjustments in caliber of pial arterioles are mediated predominantly by metabolic rather than myogenic mechanisms.

scholarly journals Intracranial and Blood Pressure Variability and Long-Term Outcome After Aneurysmal Sub-arachnoid Hemorrhage

2009 ◽  
Vol 18 (3) ◽  
pp. 241-251 ◽  
Author(s):  
Catherine J. Kirkness ◽  
Robert L. Burr ◽  
Pamela H. Mitchell
Keyword(s):  
Blood Pressure ◽  
Intensive Care ◽  
Subarachnoid Hemorrhage ◽  
Intracranial Pressure ◽  
Functional Outcome ◽  
Adaptive Capacity ◽  
Arterial Blood Pressure ◽  
Long Term Outcome ◽  
Arterial Blood

Background Care of brain-injured patients in intensive care units has focused on maintaining arterial blood pressure and intracranial pressure within prescribed ranges. Research suggests, however, that the dynamic variability of these pressure signals provides additional information about physiological functioning and may reflect adaptive capacity.Objectives To see if long-term outcomes can be predicted from variability of arterial blood pressure and intracranial pressure in patients with aneurysmal subarachnoid hemorrhage.Methods Arterial blood pressure and intracranial pressure were monitored continuously for 4 days in 90 patients (74% women; mean age, 53 years) in an intensive care unit after subarachnoid hemorrhage. Variability of arterial blood pressure and intracranial pressure signals was calculated on 4 timescales: 24 hours, 1 hour, 5 minutes, and the difference of sequential 5-second means. The Extended Glasgow Outcome Scale was used to assess functional outcome 6 months after subarachnoid hemorrhage.Results Pressure variability was better than mean pressure levels for predicting 6-month functional outcome. When initial neurological condition was controlled for, greater faster variability (particularly 5-second) was associated with better outcomes (typical P&lt;.001), whereas greater 24-hour variability was associated with poorer outcomes (typical P&lt;.001).Conclusions The relationship between long-term functional outcome and variability of arterial blood pressure and intracranial pressure levels depends on the timescale at which the variability is measured. Because it is associated with better outcome, greater faster variability may reflect better physiological adaptive capacity.

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