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 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.

Haemodynamic Monitoring in Theatre

2003 ◽  
Vol 4 (1) ◽  
pp. 10-16 ◽  
Author(s):  
Heidi Clinton
Keyword(s):  
Blood Pressure ◽  
Pulmonary Artery ◽  
Central Venous Pressure ◽  
Venous Pressure ◽  
Haemodynamic Monitoring ◽  
Pressure Monitoring ◽  
Central Venous ◽  
Noninvasive Measurements ◽  
Non Invasive ◽  
Arterial Blood

AbstractThe number of devices available to monitor the haemodynamic status of patients is increasing. Practitioners need to be aware of the non-invasive and invasive methods available in order to care for their patients safely and effectively. This article reviews a number of noninvasive measurements of haemodynamic function, in addition to invasive methods such as arterial blood pressure, central venous pressure and pulmonary artery pressure monitoring. It is argued that using these methods in combination provides a comprehensive haemodynamic assessment.

scholarly journals Crystalloid Coload vs Colloid Coload following Spinal Anesthesia for Elective Cesarean Delivery: The Effects on Maternal Central Venous Pressure

2017 ◽  
Vol 3 (4) ◽  
pp. 95-101
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Central Venous Pressure ◽  
Spinal Anesthesia ◽  
Cesarean Delivery ◽  
Venous Pressure ◽  
Elective Cesarean Delivery ◽  
Central Venous ◽  
Arterial Blood ◽  
Elective Cesarean

ABSTRACT Introduction Spinal anesthesia is widely used in the management of uncomplicated cesarean section. Maternal hypotension is the commonest serious problem which decreases uterine blood flow causing fetal hypoxia, acidosis, and neonatal depression. Fluid administration before start of the surgery (preloading) with crystalloid is found to be ineffective due to rapid redistribution of fluids in various tissue spaces. A “coload” given at the time of spinal anesthesia may be more effective. Most studies have concentrated on noninvasive systolic blood pressure (SBP) measurements to evaluate the effect of such regimens. We used central venous pressure (CVP) measurement technique in parturients receiving rapid administration of crystalloid or colloid solution at the time of initiation of anesthesia (coload). We hypothesized that a colloid coload compared with a crystalloid coload would produce a larger sustained increase in volume and therefore reduce vasopressor requirements. Materials and methods We recruited healthy term women scheduled for elective cesarean delivery under spinal anesthesia for this randomized study. Baseline heart rate, baseline mean arterial blood pressure (MAP), and CVP were recorded. At the time of spinal injection, subjects were allocated to receive a rapid 1 L coload of either polymerized gelatin 3.5% (Haemaccel) or Hartmann (crystalloid) solution. The primary outcome CVP was compared between groups, as were secondary outcomes: phenylephrine dose and maternal hemodynamics data. Results Maternal demographics, surgical times, and American Society of Anesthesiologists (ASA) were similar between groups. Baseline parameters were similar in all the three groups. Heart rate increased from the baseline in all the three groups; however, mean heart rate was highest in crystalloid group. Mean arterial blood pressure decreased in all the three groups from baseline; however, highest fall was recorded in crystalloid group. The incidence of hypotension was 66.66% in crystalloid group as compared with 36.66% in colloid group. Crystalloid group patients received 6.33 ± 4.54 mg of ephedrine as compared with 2.40 ± 2.82 mg in colloid group. Thus, the incidence of hypotension and ephedrine consumption was significantly higher in crystalloid group as compared with colloid group. We found statistically significant differences in the mean preoperative CVP reading (p < 0.05) between the two groups, the mean CVP reading in crystalloid group being slightly lower. With preloading, similar CVP readings were obtained in both groups. The fall in CVP during subarachnoid blockade was also not significant. The CVP began to fall with the establishment of the block until the delivery of the baby after which it was found to rise. The predelivery CVP was significantly lower than preoperative CVP in both groups—the fall being significantly more in crystalloid group. Conclusion In our study, the results showed statistically significant decrease in volume requirement, when colloid coload is used than crystalloid coload using CVP monitor as a guide. Colloid coloading is effective and superior to crystalloid coloading for prevention of maternal hypotension in cesarean section. How to cite this article Sivanna U. Crystalloid Coload vs Colloid Coload following Spinal Anesthesia for Elective Cesarean Delivery: The Effects on Maternal Central Venous Pressure. J Med Sci 2017;3(4):95-101.

Monitoring and equipment

2020 ◽  
pp. 59-76
Author(s):  
Anne Craig ◽  
Anthea Hatfield
Keyword(s):  
Blood Pressure ◽  
Central Venous Pressure ◽  
Pulse Oximetry ◽  
Recovery Room ◽  
Venous Pressure ◽  
Blood Gases ◽  
Central Venous ◽  
Arterial Blood ◽  
Routine Monitoring ◽  
Additional Monitoring

Routine monitoring is an essential part of recovery room procedure. Respiration, a vital concern while awakening after anaesthesia, is given specific attention with reference to modern capnography. This chapter also describes additional monitoring in detail: pulse oximetry, blood pressure, central venous pressure, and arterial blood gases are clearly described. A comprehensive description of electrocardiography guides the student through this complicated subject. The monitoring of temperature and warming blankets, with suggestions for purchasing equipment, are included.

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