scholarly journals Studies on Australian Snake Venoms. Part 1: The Haemodynamic Effects of Brown Snake (Pseudonaja) Species in the Dog

1989 ◽  
Vol 17 (4) ◽  
pp. 466-469 ◽  
Author(s):  
J. Tibballs ◽  
S. Sutherland ◽  
S. Kerr
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Venous Pressure ◽  
Haemodynamic Effects ◽  
Peripheral Vascular ◽  
Snake Venoms ◽  
Central Venous ◽  
Induced Hypotension ◽  
Mechanically Ventilated

The haemodynanic effects of Brown Snake (Pseudonaja) species (textilis, nuchalis, affinis) were investigated in anaesthetised, mechanically ventilated dogs. Blood pressure decreased to minimal levels five minutes after intravenous envenomation. Hypotension was accompanied by significant decrements in cardiac output and stroke volume and a rise in peripheral vascular resistance. Heart rate increased transiently during 0.5-2.0 minutes after envenomation but had declined below resting levels five minutes after envenomation. No statistically significant change was recorded in central venous pressure. Depression of myocardial contractility is postulated as the mechanism of venom induced hypotension.

Carotid baroreceptor control of liver and spleen volume in cats

1991 ◽  
Vol 260 (1) ◽  
pp. H254-H259
Author(s):  
R. Maass-Moreno ◽  
C. F. Rothe
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Blood Pressure ◽  
Total Peripheral Resistance ◽  
Venous Pressure ◽  
Peripheral Resistance ◽  
Normal Brain ◽  
Spleen Volume ◽  
Arterial Blood

We tested the hypothesis that the blood volumes of the spleen and liver of cats are reflexly controlled by the carotid sinus (CS) baroreceptors. In pentobarbital-anesthetized cats the CS area was isolated and perfused so that intracarotid pressure (Pcs) could be controlled while maintaining a normal brain blood perfusion. The volume changes of the liver and spleen were estimated by measuring their thickness using ultrasonic techniques. Cardiac output, systemic arterial blood pressure (Psa), central venous pressure, central blood volume, total peripheral resistance, and heart rate were also measured. In vagotomized cats, increasing Pcs by 100 mmHg caused a significant reduction in Psa (-67.8%), cardiac output (-26.6%), total peripheral resistance (-49.5%), and heart rate (-15%) and significantly increased spleen volume (9.7%, corresponding to a 2.1 +/- 0.5 mm increase in thickness). The liver volume decreased, but only by 1.6% (0.6 +/- 0.2 mm decrease in thickness), a change opposite that observed in the spleen. The changes in cardiovascular variables and in spleen volume suggest that the animals had functioning reflexes. These results indicate that in pentobarbital-anesthetized cats the carotid baroreceptors affect the volume of the spleen but not the liver and suggest that, although the spleen has an active role in the control of arterial blood pressure in the cat, the liver does not.

ANP-mediated volume depletion attenuates renal responses in humans

1992 ◽  
Vol 263 (6) ◽  
pp. R1303-R1308 ◽  
Author(s):  
T. J. Ebert ◽  
L. Groban ◽  
M. Muzi ◽  
M. Hanson ◽  
A. W. Cowley
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Central Venous Pressure ◽  
Sodium Excretion ◽  
Healthy Subjects ◽  
Venous Pressure ◽  
Urine Volume ◽  
Positive Pressure ◽  
Plasma Norepinephrine ◽  
Central Venous

Brief low-dose infusions of atrial natriuretic peptide (ANP) that emulate physiological plasma concentrations in humans have little if any effect on renal excretory function. This study explored the possibility that ANP-mediated reductions in cardiac filling pressures (through ANP's rapid effect on capillary dynamics) could attenuate its purported renal effects. Protocol A consisted of 16 healthy subjects (ages 19-27 yr old) who underwent three consecutive 45-min experimental sequences: 1) placebo, 2) ANP (10 ng.kg-1 x min-1), and 3) ANP alone (n = 8) or ANP with simultaneous lower body positive pressure (LBPP, n = 8). Electrocardiogram and direct measures of arterial and central venous pressures were continuously monitored. Blood was sampled at the end of each 45-min sequence before subjects stood to void. Compared with control (placebo), ANP produced a hemoconcentration and increased plasma norepinephrine, but did not change heart rate, blood pressure, plasma levels of renin, aldosterone, or vasopressin, or renal excretion of volume or sodium. In subjects receiving LBPP to maintain central venous pressure during the last 45 min of ANP infusion, norepinephrine did not increase and urine volume and sodium excretion increased (P < 0.05). In a second study (protocol B), five healthy subjects received a placebo infusion for 45 min followed by two consecutive 45-min infusions of ANP (10 ng.kg-1 x min-1). Central venous pressure was maintained (LBPP) at placebo baseline throughout the two ANP infusion periods. Urine volume and sodium excretion rates increased progressively and significantly during both ANP infusion periods (P < 0.05) without significant changes in creatinine clearance, blood pressure, or heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Effects of Intrathoracic Insufflation in Dogs

2002 ◽  
Vol 38 (6) ◽  
pp. 515-520 ◽  
Author(s):  
Curt M. Daly ◽  
Karen Swalec-Tobias ◽  
Anthony H. Tobias ◽  
Nicole Ehrhart
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Healthy Adult ◽  
Venous Pressure ◽  
Minute Volume ◽  
Mechanical Ventilator ◽  
Central Venous ◽  
Anesthetized Dogs ◽  
Pressure Standard

This study was designed to quantify the effects of incremental positive insufflation of the intrathoracic space on cardiac output (CO), heart rate (HR), arterial pressure (AP), central venous pressure (CVP), and percent saturation of hemoglobin with oxygen (SPO2) in anesthetized dogs. Seven healthy, adult dogs from terminal teaching laboratories were maintained under anesthesia with isoflurane delivered with a mechanical ventilator. The experimental variables were recorded before introduction of an intrathoracic catheter, at intrathoracic pressures (IP) of 0 mm Hg, 3 mm Hg insufflation, and additional increments of 1 mm Hg insufflation thereafter until the SPO2 remained &lt;85% despite increases in minute volume. Finally the variables were measured again at 0 mm Hg IP. The cardiac output and systolic and diastolic AP significantly (P&lt;0.05) decreased at 3 mm Hg IP. Significant decreases in SPO2 were seen at 10 mm Hg IP. Significant increase in CVP was noted at 6 mm Hg IP. Heart rate decreased significantly at 5 to 6 mm Hg IP but was not decreased above 6 mm Hg IP. Given the degree of CO decrease at low intrathoracic pressures, insufflation-aided thoracoscopy should be used with caution and at the lowest possible insufflation pressure. Standard anesthetic monitoring variables such as HR and AP measurements may not accurately reflect the animal’s cardiovascular status.

scholarly journals High positive end expiratory pressure levels affect hemodynamics in elderly patients with hypertension admitted to the intensive care unit: a prospective cohort study

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Lili Zhou ◽  
Guoen Cai ◽  
Zhihui Xu ◽  
Qinyong Weng ◽  
Qinyong Ye ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Elderly Patients ◽  
Airway Pressure ◽  
Heart Function ◽  
Venous Pressure ◽  
Trial Registration ◽  
Control Group ◽  
Positive End Expiratory Pressure ◽  
Central Venous

Abstract Background To study the effects of different positive end expiratory pressure (PEEP) on blood pressure and heart function in elderly patients with hypertension. Methods Forty elderly patients above 65 years of age treated with mechanical ventilation were divided into two groups: a control group of non-hypertensive subjects (n = 18) and a hypertension group (n = 22) patients with essential hypertension. Changes in blood pressure, central venous pressure (CVP), central venous oxygen saturation (ScvO2), heart rate, and airway pressure were determined in response to different selected PEEP levels of 0, 2, 4, 6, 8, 10 and 12 cm H2O under SIMV(PC) + PSV mode throughout the study. Results In both groups, the increase in PEEP led to an increase in CVP and airway pressure. When PEEP was above 4 cm H2O in the hypertension group, a decrease in blood pressure and ScvO2, and an increase of heart rate were observed. These results indicated that cardiac output significantly decreased. Conclusion High levels of PEEP can significantly influence changes in blood pressure and heart function in elderly patients with hypertension. Trial registration This trial was retrospectively registered, The Chinese trial registration number is ChiCTR-ROC-17012873. The date of registration is 10-2-2017.

scholarly journals A Comparison between Ketamine and Diazepam as Induction Agents for Pericardiectomy

1978 ◽  
Vol 6 (1) ◽  
pp. 66-70 ◽  
Author(s):  
H. G. G. Kingston ◽  
K. W. Bretherton ◽  
A. M. Holloway ◽  
and J. W. Downing
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Cardiac Index ◽  
Central Venous Pressure ◽  
Systemic Vascular Resistance ◽  
Venous Pressure ◽  
Significant Rise ◽  
Central Venous ◽  
Induction Of Anaesthesia ◽  
Induction Agents

Ketamine 1 · 0 mg/kg and diazepam 0 · 3 mg/kg was used to induce anaesthesia in patients requiring pericardiectomy. A significant rise in blood pressure in patients receiving ketamine was noted. In contrast, a fall in blood pressure was seen when diazepam was administered. Changes in cardiac output, cardiac index, central venous pressure and systemic vascular resistance are discussed. Ketamine appears to be a more satisfactory agent for induction of anaesthesia in patients for pericardiectomy, whereas diazepam should be used with caution.

Stroke Volume Optimization: The New Hemodynamic Algorithm

2015 ◽  
Vol 35 (1) ◽  
pp. 11-27 ◽  
Author(s):  
Alexander Johnson ◽  
Thomas Ahrens
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Venous Pressure ◽  
Optimization Strategy ◽  
Central Venous ◽  
Hemodynamic Optimization ◽  
Level Of Consciousness ◽  
Cardiac Output Monitor ◽  
Care Practices

Critical care practices have evolved to rely more on physical assessments for monitoring cardiac output and evaluating fluid volume status because these assessments are less invasive and more convenient to use than is a pulmonary artery catheter. Despite this trend, level of consciousness, central venous pressure, urine output, heart rate, and blood pressure remain assessments that are slow to be changed, potentially misleading, and often manifested as late indications of decreased cardiac output. The hemodynamic optimization strategy called stroke volume optimization might provide a proactive guide for clinicians to optimize a patient’s status before late indications of a worsening condition occur. The evidence supporting use of the stroke volume optimization algorithm to treat hypovolemia is increasing. Many of the cardiac output monitor technologies today measure stroke volume, as well as the parameters that comprise stroke volume: preload, afterload, and contractility.

Aortocaval fistula delays gastric emptying of liquid test meal in awake rats

2013 ◽  
Vol 304 (10) ◽  
pp. H1397-H1405 ◽  
Author(s):  
Moisés T. B. Silva ◽  
Raimundo C. Palheta ◽  
Francisca G. V. Oliveira ◽  
Juliana B. M. de Lima ◽  
José Antunes-Rodrigues ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Gastric Emptying ◽  
Central Venous Pressure ◽  
Test Meal ◽  
Venous Pressure ◽  
Aortocaval Fistula ◽  
Central Venous ◽  
Dye Retention ◽  
Awake Rats

Arteriovenous anastomoses disrupt cardiovascular and renal homeostasis, eliciting hemodynamic adjustments, resetting the humoral pattern, and inducing cardiac hypertrophy. Because acute circulatory imbalance alters gut motor behavior, we studied the effects of arteriovenous fistula placement on the gastric emptying (GE) of a liquid meal in awake rats. After laparotomy, we created an aortocaval fistula (ACF) by aorta and cava wall puncture with a 21-, 23-, or 26-gauge needle. The ACF was not created in the control group, which underwent sham operation. After 12, 24, or 48 h, mean arterial pressure, heart rate, and central venous pressure were continuously recorded, and cardiac output was estimated by thermal dilution. The rats were then gavage fed a test meal (i.e., phenol red in glucose solution), and fractional dye retention was determined 10, 20, or 30 min later. The effect of prior bleeding on ACF-induced GE delay, the role of neuroautonomic pathways, and changes in plasma hormone levels (i.e., angiotensin II, arginine vasopressin, atrial natriuretic peptide, corticosterone, and oxytocin) were evaluated. When compared with the sham-operated group, ACF rats exhibited arterial hypotension, higher ( P < 0.05) heart rate, central venous pressure, and cardiac output values and increased ( P < 0.05) gastric dye retention, a phenomenon prevented by bilateral subdiaphragmatic vagotomy and hexamethonium treatment. Pirenzepine also impaired the occurrence of gastric delay in subjects with ACF. In addition to causing hyperkinetic circulation, ACF placement delayed the GE of liquid in awake rats, an effect that likely involves a parasympathetic pathway.

scholarly journals Haemodynamic Effects of Pericardial Closure after Cardiac Surgery

2020 ◽  
Vol 8 (1) ◽  
pp. 81-85
Author(s):  
Saurabh KS ◽  
AK Padhy ◽  
Madhur Kumar ◽  
R Munjal ◽  
A. Gupta
Keyword(s):  
Cardiac Output ◽  
Cardiac Surgery ◽  
Valve Replacement ◽  
Artery Bypass ◽  
Venous Pressure ◽  
Left Ventricular ◽  
Haemodynamic Effects ◽  
Bypass Grafting ◽  
Central Venous ◽  
Double Valve Replacement

Introduction: Whether pericardial closure should be done or not is still a debated topic. While many studies favour pericardial closure after cardiac surgery, many are still not in favour of the same. Objective : Objective of this study was to analyse the changes induced by pericardial closure on the haemodynamic of the patient using easily measurable variables. Methods : Data of 30 patients were analysed of which 14 underwent mitral valve replacement, 10 underwent coronary artery bypass grafting and 6 underwent double valve replacement. Results: There was statistically significant change in cardiac output (p<0.01), central venous pressure (p<0.05) and left ventricular end diastolic diameter (p<0.01) after pericardial closure. Clinically the pericardial closure was well tolerated. Conclusion: Despite exhaustive experience, the topic of closing pericardium is still debated. Our study shows that clinically pericardial closure is well tolerated and in return it also safeguards the risks associated with re-do operations

Effect of position on selected hemodynamic parameters in postoperative cardiac surgery patients

1994 ◽  
Vol 3 (4) ◽  
pp. 289-299 ◽  
Author(s):  
RJ Emerson ◽  
JL Banasik
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Surgery ◽  
Central Venous Pressure ◽  
Lung Disease ◽  
Artery Bypass ◽  
Venous Pressure ◽  
Bypass Graft ◽  
Central Venous ◽  
Noninvasive Blood Pressure

BACKGROUND: Indirect/noninvasive blood pressure, heart rate and central venous pressure are frequently monitored hemodynamic parameters in postoperative cardiac surgery patients. No previous studies have explored the effect of lateral position on these variables in this population. OBJECTIVES: To determine differences in (1) blood pressure, central venous pressure, or heart rate measurements among postoperative cardiac surgery patients due to position (supine, 45 degrees right lateral, and 45 degrees left lateral), (2) responses to position between patients having cardiac surgery in which the myocardium was opened (valvular replacement) and those in which it was not (coronary artery bypass graft), and (3) responses to position between cardiac surgery patients having preoperatively diagnosed lung disease and those without lung disease. METHODS: Phlebostatic axis in lateral positions was determined by echocardiography and geometric diagrams prior to the initiation of data collection. Postoperative cardiac surgery patients (N = 120) were studied in the three positions in random sequences. In each position, simultaneous blood pressure measurements were obtained from each arm, and central venous pressure and heart rate were recorded. RESULTS: Statistically significant differences were found in response to position in systolic and diastolic blood pressure, central venous pressure, and heart rate. Certain positions produced greater changes in selected variables, both in the total group and within specific subgroups. No differences were found between coronary artery bypass graft and valve (closed or opened myocardium) subgroups or between subgroups with and without lung disease. CONCLUSIONS: Lateral positioning of postoperative cardiac surgery patients appears to cause no detrimental effects on indirect/noninvasive blood pressure or heart rate measurements. However, significant differences in central venous pressure may occur and supine positioning for determination of central venous pressure is recommended.

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