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<.001), whereas greater 24-hour variability was associated with poorer outcomes (typical P<.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.

scholarly journals Functional relationship of arterial blood pressure, central venous pressure and intracranial pressure in the early phase after subarachnoid hemorrhage

2021 ◽  
pp. 1-14
Author(s):  
Gabriela Maissen ◽  
Gagan Narula ◽  
Christian Strässle ◽  
Jan Willms ◽  
Carl Muroi ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Subarachnoid Hemorrhage ◽  
Intracranial Pressure ◽  
Central Venous Pressure ◽  
Arterial Blood Pressure ◽  
Functional Relationship ◽  
Venous Pressure ◽  
Correlation Coefficients ◽  
Central Venous ◽  
Arterial Blood

BACKGROUND: Intracranial pressure (ICP) and arterial blood pressure (ABP) are related to each other through cerebral autoregulation. Central venous pressure (CVP) is often measured to estimate cardiac filling pressures as an approximate measure for the volume status of a patient. Prior modelling efforts have formalized the functional relationship between CVP, ICP and ABP. However, these models were used to explain short segments of data during controlled experiments and have not yet been used to explain the slowly evolving ICP increase that occurs typically in patients after aneurysmal subarachnoid hemorrhage (SAH). OBJECTIVE: To analyze the functional relationship between ICP, ABP and CVP recorded from SAH patients in the first five days after aneurysm. METHODS: Two methods were used to elucidate this relationship on the running average of the signals: First, using Spearman correlation coefficients calculated over 30 min segments Second, for each patient, linear state space models of ICP as the output and ABP and CVP as inputs were estimated. RESULTS: The mean and variance of the data and the correlation coefficients between ICP-ABP and ICP-CVP vary over time as the patient progresses through their stay in the ICU. On average, after an SAH event, the models show that a) ABP is the bigger driver of changes in ICP than CVP and that increasing ABP leads to reduction in ICP and (b) increasing CVP leads to an increase in ICP. CONCLUSIONS: Finding a) agrees with the hypothesis that patients with subarachnoid hemorrhage have defective autoregulation, and b) agrees with the positive correlation observed between central venous pressure and intracranial pressure in the literature.

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.

scholarly journals Assessment of the Subarachnoid Hemorrhage International Trialists (SAHIT) Models for Dichotomized Long-Term Functional Outcome Prediction After Aneurysmal Subarachnoid Hemorrhage in a United Kingdom Multicenter Cohort Study

Neurosurgery ◽  
2020 ◽  
Author(s):  
Isabel C Hostettler ◽  
Menelaos Pavlou ◽  
Gareth Ambler ◽  
Varinder S Alg ◽  
Stephen Bonner ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Functional Outcome ◽  
Outcome Prediction ◽  
Prediction Models ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Predictive Performance ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Fisher Grade

Abstract BACKGROUND Long-term outcome after subarachnoid hemorrhage, beyond the first few months, is difficult to predict, but has critical relevance to patients, their families, and carers. OBJECTIVE To assess the performance of the Subarachnoid Hemorrhage International Trialists (SAHIT) prediction models, which were initially designed to predict short-term (90 d) outcome, as predictors of long-term (2 yr) functional outcome after aneurysmal subarachnoid hemorrhage (aSAH). METHODS We included 1545 patients with angiographically-proven aSAH from the Genetic and Observational Subarachnoid Haemorrhage (GOSH) study recruited at 22 hospitals between 2011 and 2014. We collected data on age, WNFS grade on admission, history of hypertension, Fisher grade, aneurysm size and location, as well as treatment modality. Functional outcome was measured by the Glasgow Outcome Scale (GOS) with GOS 1 to 3 corresponding to unfavorable and 4 to 5 to favorable functional outcome, according to the SAHIT models. The SAHIT models were assessed for long-term outcome prediction by estimating measures of calibration (calibration slope) and discrimination (area under the receiver-operating characteristic curve [AUC]) in relation to poor clinical outcome. RESULTS Follow-up was standardized to 2 yr using imputation methods. All 3 SAHIT models demonstrated acceptable predictive performance for long-term functional outcome. The estimated AUC was 0.71 (95% CI: 0.65-0.76), 0.73 (95% CI: 0.68-0.77), and 0.74 (95% CI: 0.69-0.79) for the core, neuroimaging, and full models, respectively; the calibration slopes were 0.86, 0.84, and 0.89, indicating good calibration. CONCLUSION The SAHIT prediction models, incorporating simple factors available on hospital admission, show good predictive performance for long-term functional outcome after aSAH.

Effects of isoproterenol on the cardiovascular system of fetal sheep exposed to long-term high-altitude hypoxemia

1995 ◽  
Vol 78 (5) ◽  
pp. 1793-1799 ◽  
Author(s):  
M. Kamitomo ◽  
T. Ohtsuka ◽  
R. D. Gilbert
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Right Ventricular ◽  
High Altitude ◽  
Arterial Blood Pressure ◽  
Left Ventricular ◽  
Arterial Blood ◽  
Isoproterenol Infusion

We exposed fetuses to high-altitude (3,820 m) hypoxemia from 30 to 130 days gestation, when we measured fetal heart rate, right and left ventricular outputs with electromagnetic flow probes, and arterial blood pressure during an isoproterenol dose-response infusion. We also measured the distribution of cardiac output with radiolabeled microspheres during the maximal isoproterenol dose. Baseline fetal arterial blood pressure was higher in long-term hypoxemic fetuses (50.1 +/- 1.3 vs. 43.4 +/- 1.0 mmHg) but fell during the isoproterenol infusion to 41.3 +/- 1.4 and 37.5 +/- 1.4 mmHg, respectively, at the highest dose. Heart rate was the same in both groups and did not differ during isoproterenol infusion. Baseline fetal cardiac output was lower in the hypoxemic group (339 +/- 18 vs. 436 +/- 19 ml.min-1.kg-1) due mainly to a reduction in right ventricular output. During the isoproterenol infusion, right ventricular output increased to the same extent in both hypoxemic and normoxic fetuses (approximately 35%); however, left ventricular output increased only approximately 15% in the hypoxemic group compared with approximately 40% in the normoxic group. The percent change in individual organ blood flows during isoproterenol infusion in the hypoxemic groups was not significantly different from the normoxic group. All of the mechanisms that might be responsible for the differential response of the fetal left and right ventricles to long-term hypoxia are not understood and need further exploration.

Long-Term Telemetry of Direct Arterial Blood Pressure in Unrestricted Hypertensives

2015 ◽  
pp. 211-215
Author(s):  
B. Kr�nig ◽  
K. Dufey ◽  
P. Reinhardt ◽  
J. Jahnecke ◽  
H. P. Wolff
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Arterial Blood ◽  
Direct Arterial Blood Pressure

scholarly journals Significance of the Cerebrovascular Effects of Immobilization Stress in the Rabbit

1984 ◽  
Vol 4 (3) ◽  
pp. 397-406 ◽  
Author(s):  
Pierre Lacombe ◽  
Jacques Seylaz
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Immobilization Stress ◽  
Sampling Technique ◽  
Stress Reaction ◽  
Acute Hypertension ◽  
Cerebrovascular Autoregulation ◽  
Arterial Blood ◽  
Systemic Factors

The question of the significance of the cerebrovascular effects of stressful situations in animals is still controversial. In the present article, an experimental model of immobilization stress in the rabbit is described, and its specificity in relation to arterial blood pressure and PaCO2 is investigated. CBF was measured with the multiregional tissue sampling technique using [14C]-ethanol as tracer. After dissipation of althesin anesthesia, the stress reaction was elicited by tactile abdominal stimuli. The response was evidenced by an instantaneous acute hypertension (+ 33.8% during the CBF measurement period). Within the first minute of the reaction, the CBF was significantly increased in all nine structures studied by 39% (caudate nucleus) to 82% (parietotemporal cortex). The study of the influence of arterial blood pressure and the PaCO2 on CBF showed that cerebrovascular autoregulation and CO2 sensitivity were differently affected in the various structures during the stress reaction. However, the stress response of the brain circulation could not be entirely ascribed to one or both of these two systemic factors, thus suggesting the contribution of a local intrinsic activation. The model presented here could be useful for long-term studies of cerebrovascular repercussions of repeated acute hypertensions of a stressful nature.

Endogenous arterial blood pressure increase after aneurysmal subarachnoid hemorrhage

2020 ◽  
Vol 190 ◽  
pp. 105639
Author(s):  
Arthur Hosmann ◽  
Sarah Klenk ◽  
Wei-te Wang ◽  
Johannes Koren ◽  
Samir Sljivic ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Subarachnoid Hemorrhage ◽  
Arterial Blood Pressure ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Pressure Increase ◽  
Blood Pressure Increase ◽  
Arterial Blood
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