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.

Functional Interaction between Angiotensin and Sympathetic Reflexes in Cats

1982 ◽  
Vol 62 (1) ◽  
pp. 51-56 ◽  
Author(s):  
R. Hatton ◽  
D. P. Clough ◽  
S. A. Adigun ◽  
J. Conway
Keyword(s):  
Blood Pressure ◽  
Central Venous Pressure ◽  
Arterial Blood Pressure ◽  
Venous Pressure ◽  
Partial Recovery ◽  
Ang Ii ◽  
Central Venous ◽  
Efferent Nerve ◽  
Arterial Blood ◽  
Sympathetic Reflexes

1. Lower-body negative pressure (LBNP) was used to stimulate sympathetic reflexes in anaesthetized cats. At −50 mmHg for 10 min it caused transient reduction in central venous pressure and systemic arterial blood pressure. Arterial blood pressure was then restored within 30 s and there was a tachycardia. Central venous pressure showed only partial recovery. The resting level of plasma renin activity (PRA; 2.9–3.2 ng h−1 ml−1) did not change until approximately 5 min into the manoeuvre. 2. When converting-enzyme inhibitor (CEI) was given 75 s after the onset of suction it caused a greater and more sustained fall in arterial blood pressure than when administered alone. The angiotensin II (ANG II) antagonist [Sar1,Ala8]ANG II produced similar effects after a short-lived pressor response. 3. This prolonged fall in arterial blood pressure produced by CEI was not associated with reduced sympathetic efferent nerve activity. This indicates that the inhibitor affects one of the peripheral actions of angiotensin and in so doing produces vasodilatation of neurogenic origin. 4. These findings suggest that angiotensin, at a level which does not exert a direct vasoconstrictor action, interacts with the sympathetic nervous system to maintain arterial blood pressure when homeostatic reflexes are activated. A reduction in the efficiency of these reflexes by CEI may contribute to its hypotensive effect.

Hemorrhage in newborn lambs: effects on arterial blood pressure, ACTH, cortisol, and vasopressin

1981 ◽  
Vol 240 (6) ◽  
pp. E585-E590 ◽  
Author(s):  
J. C. Rose ◽  
M. Morris ◽  
P. J. Meis
Keyword(s):  
Blood Pressure ◽  
Central Venous Pressure ◽  
Arterial Blood Pressure ◽  
Blood Volume ◽  
Venous Pressure ◽  
Plasma Concentrations ◽  
Central Venous ◽  
Arterial Blood ◽  
Age Related ◽  
Mean Pressure

Arterial blood pressure, central venous pressure, and plasma concentrations of ACTH, cortisol, and vasopressin (AVP) were monitored in chronically prepared, unanesthetized newborn and weanling lambs at rest and during and after hemorrhage of 15% of estimated blood volume at 1.5%/min. Differences in the endocrine and blood pressure responses to hypovolemia were noted in the two groups of animals. Hemorrhage did not change arterial mean pressure, reduced central venous pressure, and caused a delayed increase in the plasma concentrations of ACTH, cortisol, and AVP in the newborn lambs. In weanling lambs, hemorrhage reduced arterial mean pressure and central venous pressure and promptly increased plasma ACTH and cortisol levels while plasma AVP concentrations again showed a delayed increase. The data indicate that certain hormonal mechanisms for the defense of blood volume are present and operational within 3 days of birth and that age-related differences in the responses to hemorrhage exist in the lamb.

scholarly journals Physiological monitoring - an experimental evaluation

1971 ◽  
Author(s):  
◽  
Judith A. Taylor
Keyword(s):  
Blood Pressure ◽  
Central Venous Pressure ◽  
Arterial Blood Pressure ◽  
Medical Center ◽  
Venous Pressure ◽  
Physiological Data ◽  
Critically Ill Patient ◽  
Physiological Parameter ◽  
Central Venous ◽  
Arterial Blood

"Observation of post operative nursing care in the Thoracic Intensive Care Unit (ICU) of a state medical center revealed that the staff, both nurses and physicians, questioned the reliability of the direct arterial and venous blood pressure measurements. Nurses frequently used more than one method in an effort to obtain the same physiological data. An example was the measuring of arterial blood pressure suing both the monitor and the sphygmomanometer. This then necessitated subjecting the critically ill patient to an extra procedure and added discomfort in order to record the same physiological parameter. The staff also preferred to use the water manometer for measuring central venous pressure, rather than the monitor, when it was available to them because they doubted the accuracy of the monitor readings...A study of post operative open-heart patients in the Thoracic ICU of a state medical center was then initiated with the following specific aims: (1) to evaluate the monitoring equipment in the ICU in terms of its precision and consistency, (2) to evaluate the comparative response of the monitor versus the sphygmomanometer in the measurement of arterial blood pressure, and the monitor versus the water manometer in the measurement of central venous pressure, (3) to determine whether or not actual alterations of the physiological parameters of heart rate, arterial blood pressure and central venous pressure occur with position change and, if so, are they of clinical significance, and finally, (4) to make suggestions regarding the measurement of these parameters by nursing personnel."-Introduction

scholarly journals Prospective Study of Central Venous Pressure Trends during Major Neurosurgical Procedures in an Elective Operation Theatre Setting of a Tertiary Care Centre

2021 ◽  
Vol 8 (07) ◽  
pp. 369-373
Author(s):  
Rajeev Damodaran Sarojini ◽  
Sanjay Sahadevan ◽  
Jayakumar Christhudas
Keyword(s):  
Blood Pressure ◽  
Intracranial Pressure ◽  
Prospective Study ◽  
Central Venous Pressure ◽  
Inferior Vena ◽  
Venous Pressure ◽  
Ultra Sound ◽  
Neurosurgical Procedures ◽  
Central Venous ◽  
Intraoperative Period

BACKGROUND There are extensive variations in central venous pressure during intraoperative period of a major neurosurgical patients. Monitoring of central venous pressure is vital for guiding the administration of fluids, blood and blood products. Central venous pressure (CVP) also measures the intracranial pressure indirectly. Increased intracranial pressure thereby reduces the cerebral blood flow, leading to cerebral ischemia. METHODS This is a prospective study where 25 major neurosurgical cases posted for elective major neurosurgery were selected. Right subclavian vein was selected for cannulation, by blind technique in all these cases. CVP was recorded every 15 minutes. Central venous catheter was connected to a pressure transducer linked to a multichannel monitor; zeroing was done and the CVP reading obtained. RESULTS Central venous pressure reading was done serially and showed the trends in haemodynamics in various stages of surgery. Initial intraoperative periods showed lower values due to intravenous (I / V) induction of anaesthesia, use of mannitol and diuretics. Later on, the trends changed to higher side subsequent to administration of fluids and blood as required. CONCLUSIONS Monitoring of CVP is an important component of haemodynamic monitoring along with non-invasive blood pressure (NIBP), intra-arterial blood pressure (IABP), and urine output. Central venous pressure can be used to aspirate an air embolism occurring during the intraoperative period after employing Durant’s position. KEYWORDS CVP, NIBP , USS – Ultra Sound Scan, IVC – Inferior Vena Cava, IVCCI – Inferior Vena Cave Collapsibility Index, PEEP – Positive End Expiratory Pressure, C / L – Central Line, IABP.

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<.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.

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