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Central Venous Pressure (central + venous_pressure)

Distribution by Scientific Domains

Medical Sciences	85%
Life Sciences	14%

Distribution within Medical Sciences

Anesthesia & Pain Management	41%
Transplantation	11%
Cardiovascular Disease	8%
7 Other Subdomains	32%

Selected Abstracts

Low Central Venous Pressure with Milrinone During Living Donor Hepatectomy

AMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2010
H.-G. Ryu
Maintaining a low central venous pressure (CVP) has been frequently used in liver resections to reduce blood loss. However, decreased preload carries potential risks such as hemodynamic instability. We hypothesized that a low CVP with milrinone would provide a better surgical environment and hemodynamic stability during living donor hepatectomy. Thirty-eight healthy adult liver donors were randomized to receive either milrinone (milrinone group, n = 19) or normal saline (control group, n = 19) infusion during liver resection. The surgical field was assessed using a four-point scale. Intraoperative vital signs, blood loss, the use of vasopressors and diuretics and postoperative laboratory data were compared between groups. The milrinone group showed a superior surgical field (p < 0.001) and less blood loss (142 ± 129 mL vs. 378 ± 167 mL, p < 0.001). Vital signs were well maintained in both groups but the milrinone group required smaller amounts of vasopressors and less-frequent diuretics to maintain a low CVP. The milrinone group also showed a more rapid recovery pattern after surgery. Milrinone-induced low CVP improves the surgical field with less blood loss during living donor hepatectomy and also has favorable effects on intraoperative hemodynamics and postoperative recovery. [source]

Forearm vascular and neuroendocrine responses to graded water immersion in humans

ACTA PHYSIOLOGICA, Issue 2 2000
Gabrielsen
The hypothesis that graded expansion of central blood volume by water immersion to the xiphoid process and neck would elicit a graded decrease in forearm vascular resistance was tested. Central venous pressure increased (P < 0.05) by 4.2 ± 0.4 mmHg (mean ± SEM) during xiphoid immersion and by 10.4 ± 0.5 mmHg during neck immersion. Plasma noradrenaline was gradually suppressed (P < 0.05) by 62 ± 8 and 104 ± 11 pg mL,1 during xiphoid and neck immersion, respectively, indicating a graded suppression of sympathetic nervous activity. Plasma concentrations of arginine vasopressin were suppressed by 1.5 ± 0.5 pg mL,1 (P < 0.05) during xiphoid immersion and by 2.0 ± 0.5 pg mL,1 during neck immersion (P < 0.05 vs. xiphoid immersion). Forearm subcutaneous vascular resistance decreased to the same extent by 26 ± 9 and 28 ± 4% (P < 0.05), respectively, during both immersion procedures, whereas forearm skeletal muscle vascular resistance declined only during neck immersion by 27 ± 6% (P < 0.05). In conclusion, graded central blood volume expansion initiated a graded decrease in sympathetic nervous activity and AVP-release. Changes in forearm subcutaneous vascular resistance, however, were not related to the gradual withdrawal of the sympathetic and neuroendocrine vasoconstrictor activity. Forearm skeletal muscle vasodilatation exhibited a more graded response with a detectable decrease only during immersion to the neck. Therefore, the forearm subcutaneous vasodilator response reaches saturation at a lower degree of central volume expansion than that of forearm skeletal muscle. [source]

Tricuspid Valve Malfunction and Ventricular Pacemaker Lead: Case Report and Review of the Literature

ECHOCARDIOGRAPHY, Issue 8 2006
Said B. Iskandar M.D.
Pacemaker implantation can be associated with several complications, including myocardial perforation with or without pericardial effusion, venous thrombosis, vegetations of the tricuspid valve (TV) or pacing lead, and tricuspid regurgitation (TR). The TR is thought to be derived from deformity or perforation of the TV by the pacing lead or secondary to atrioventricular discordance with asynchronous ventricular pacing. Severe TR can be deleterious to the patient because it raises the central venous pressure by increasing the right sided preload. Chronically, the increase in right sided blood volume can result in an increase in the right atrial pressure leading to a decrease in venous return and low cardiac output. Severe TR from leaflet adhesion to the pacemaker lead has not been reported before. With the aging of the population and the expanding use of pacemakers and implantable cardioverter defibrillators (ICD) in clinical practice, this complication may be seen more frequently. We present a patient diagnosed with severe TR, years after his pacemaker implantation. His TR was thought to be caused by adhesion of the tricuspid valve to his pacemaker lead. [source]

Cardiovascular Response to Graded Lower Body Negative Pressure in Young and Elderly Man

EXPERIMENTAL PHYSIOLOGY, Issue 3 2001
R. van Hoeyweghen
Lower body negative pressure (LBNP) reduces central venous pressure (CVP) and cardiac output. The elderly are reported to have a limited capacity to increase cardiac output by increasing heart rate (HR), are especially dependent on end diastolic volume to maintain stroke volume and therefore should be especially vulnerable to LBNP. The present study compared the effects of LBNP in the young and old. Stroke volume was assessed non-invasively as stroke distance (SD) by aortovelography. Two groups of healthy male volunteers were studied: eight young (29.7 ± 2.0 years, mean ± S.E.M.) and nine old (70.1 ± 0.9 years). LBNP was applied progressively at 17.5, 35 and 50 mmHg in 20 min steps, with measurements taken during each steady state. There were similar, significant, falls in CVP in both groups. SD fell significantly in both groups from respective control values of 24.8 ± 1.6 and 16.6 ± 0.9 cm to 12.5 ± 1.3 and 8.9 ± 0.4 cm at a LBNP of 50 mmHg. Although SD in the elderly was significantly lower than in the young, the LBNP-induced changes were not different between groups. Both groups produced similar significant increases in vascular resistance, HR, plasma vasopressin (AVP) and noradrenaline. Mean arterial blood pressure (MBP) and plasma adrenaline did not change significantly. Therefore healthy old men respond to LBNP in a similar manner to the young, although MBP and SD are regulated around different baselines in the two groups. [source]

Cardiovascular and Metabolic Effects of High-dose Insulin in a Porcine Septic Shock Model

ACADEMIC EMERGENCY MEDICINE, Issue 4 2010
Joel S. Holger MD
Abstract Objectives:, High-dose insulin (HDI) has inotropic and vasodilatory properties in various clinical conditions associated with myocardial depression. The authors hypothesized that HDI will improve the myocardial depression produced by severe septic shock and have beneficial effects on metabolic parameters. In an animal model of severe septic shock, this study compared the effects of HDI treatment to normal saline (NS) resuscitation alone. Methods:, Ten pigs were randomized to an insulin (HDI) or NS group. All were anesthetized and instrumented to monitor cardiovascular function. In both arms, Escherichia coli endotoxin lipopolysaccharide (LPS) and NS infusions were begun. LPS was titrated to 20 ,g/kg/hour over 30 minutes and continued for 5 hours, and saline was infused at 20 mL/kg/hour throughout the protocol. Dextrose (50%) was infused to maintain glucose in the 60,150 mg/dL range, and potassium was infused to maintain a level greater than 2.8 mmol/L. At 60 minutes, the HDI group received an insulin infusion titrated from 2 to 10 units/kg/hour over 40 minutes and continued at that rate throughout the protocol. Survival, heart rate (HR), mean arterial pressure (MAP), pulmonary artery and central venous pressure, cardiac output, central venous oxygen saturation (SVO2), and lactate were monitored for 5 hours (three pigs each arm) or 7 hours (two pigs each arm) or until death. Cardiac index, systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), O2 delivery, and O2 consumption were derived from measured data. Outcomes from the repeated-measures analysis were modeled using a mixed-effects linear model that assumed normally distributed errors and a random effect at the subject level. Results:, No significant baseline differences existed between arms at time 0 or 60 minutes. Survival was 100% in the HDI arm and 60% in the NS arm. Cardiovascular variables were significantly better in the HDI arm: cardiac index (p < 0.001), SVR (p < 0.003), and PVR (p < 0.01). The metabolic parameters were also significantly better in the HDI arm: SVO2 (p < 0.01), O2 delivery (p < 0.001), and O2 consumption (p < 0.001). No differences in MAP, HR, or lactate were found. Conclusions:, In this animal model of endotoxemic-induced septic shock that results in severe myocardial depression, HDI is associated with improved cardiac function compared to NS resuscitation alone. HDI also demonstrated favorable metabolic, pulmonary, and peripheral vascular effects. Further studies may define a potential role for the use of HDI in the resuscitation of septic shock. ACADEMIC EMERGENCY MEDICINE 2010; 17:429,435 © 2010 by the Society for Academic Emergency Medicine [source]

Norepinephrine causes a pressure-dependent plasma volume decrease in clinical vasodilatory shock

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2010
A. NYGREN
Background: Recent experimental studies have shown that a norepinephrine-induced increase in blood pressure induces a loss of plasma volume, particularly under increased microvascular permeability. We studied the effects of norepinephrine-induced variations in the mean arterial pressure (MAP) on plasma volume changes and systemic haemodynamics in patients with vasodilatory shock. Methods: Twenty-one mechanically ventilated patients who required norepinephrine to maintain MAP ,70 mmHg because of septic/postcardiotomy vasodilatory shock were included. The norepinephrine dose was randomly titrated to target MAPs of 60, 75 and 90 mmHg. At each target MAP, data on systemic haemodynamics, haematocrit, arterial and mixed venous oxygen content and urine flow urine were measured. Changes in the plasma volume were calculated as 100 × (Hctpre/Hctpost,1)/ (1,Hctpre), where Hctpre and Hctpost are haematocrits before and after intervention. Results: Norepinephrine doses to obtain target MAPs of 60, 75 and 90 mmHg were 0.20±0.18, 0.29±0.18 and 0.42±0.31 ,g/kg/min, respectively. From 60 to 90 mmHg, increases in the cardiac index (15%), systemic oxygen delivery index (25%), central venous pressure (CVP) (20%) and pulmonary artery occlusion pressure (33%) were seen, while the intrapulmonary shunt fraction was unaffected by norepinehrine. Plasma volume decreased by 6.5% and 9.4% (P<0.0001) when blood pressure was increased from 60 to 75 and 90 mmHg, respectively. MAP (P<0.02) independently predicted the decrease in plasma volume with norepinephrine but not CVP (P=0.19), cardiac index (P=0.73), norepinephrine dose (P=0.58) or urine flow (P=0.64). Conclusions: Norepinephrine causes a pressure-dependent decrease in the plasma volume in patients with vasodilatory shock most likely caused by transcapillary fluid extravasation. [source]

Global and right ventricular end-diastolic volumes correlate better with preload after correction for ejection fraction

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2010
M. L. N. G. MALBRAIN
Background: Volumetric monitoring with right ventricular end-diastolic volume indexed (RVEDVi) and global end-diastolic volume indexed (GEDVi) is increasingly being suggested as a superior preload indicator compared with the filling pressures central venous pressure (CVP) or the pulmonary capillary wedge pressure (PCWP). However, static monitoring of these volumetric parameters has not consistently been shown to be able to predict changes in cardiac index (CI). The aim of this study was to evaluate whether a correction of RVEDVi and GEDVi with a measure of the individual contractile reserve, assessed by right ventricular ejection fraction (RVEF) and global ejection fraction, improves the ability of RVEDVi and GEDVi to monitor changes in preload over time in critically ill patients. Methods: Hemodynamic measurements, both by pulmonary artery and by transcardiopulmonary thermodilution, were performed in 11 mechanically ventilated medical ICU patients. Correction of volumes was achieved by normalization to EF deviation from normal EF values in an exponential fashion. Data before and after fluid administration were obtained in eight patients, while data before and after diuretics were obtained in seven patients. Results: No correlation was found between the change in cardiac filling pressures (,CVP, ,PCWP) and ,CI (R2 0.01 and 0.00, respectively). Further, no correlation was found between ,RVEDVi or ,GEDVi and ,CI (R2 0.10 and 0.13, respectively). In contrast, a significant correlation was found between ,RVEDVi corrected to RVEF (,cRVEDVi) and ,CI (R2 0.64), as well as between ,cGEDVi and ,CI (R2 0.59). An increase in the net fluid balance with +844 ± 495 ml/m2 resulted in a significant increase in CI of 0.5 ± 0.3 l/min/m2; however, only ,cRVEDVi (R2 0.58) and ,cGEDVi (R2 0.36) correlated significantly with ,CI. Administration of diuretics resulting in a net fluid balance of ,942 ± 658 ml/m2 caused a significant decrease in CI with 0.7 ± 0.5 l/min/m2; however, only ,cRVEDVi (R2 0.80) and ,cGEDVi (R2 0.61) correlated significantly with ,CI. Conclusion: Correction of volumetric preload parameters by measures of ejection fraction improved the ability of these parameters to assess changes in preload over time in this heterogeneous group of critically ill patients. [source]

Haemodynamic effects of ,75 mmHg negative pressure therapy in a porcine sternotomy wound model

INTERNATIONAL WOUND JOURNAL, Issue 1 2009
Arash Mokhtari
Abstract Previous research has shown ,125 mmHg to be the optimal negative pressure for creating an environment that promotes wound healing, and this has therefore been adopted as a standard pressure for patients with deep sternal wound infection. However, it has not yet been clearly shown that ,125 mmHg is the optimal pressure from a haemodynamic point of view. Furthermore, there have been reports of cardiac rupture during ,125 mmHg negative pressure therapy. We therefore studied the effects of a lower pressure: ,75 mmHg. Twelve pigs were used. After median sternotomy, sealed negative pressure therapy of ,75 mmHg was applied. Baseline measurements were made and continuous recording of the cardiac output, end-tidal CO2 production, mean arterial pressure, mean pulmonary pressure (pulmonary artery pressure), systemic vascular resistance, pulmonary vascular resistance, left atrial pressure and central venous pressure was started. Six pigs served as controls. No statistically significant difference was observed in any of the haemodynamic parameters studied, compared with the controls. The present study shows that, with a suitable foam application technique, ,75 mmHg can be applied without compromising the central haemodynamics. [source]

Automated pre-ejection period variation predicts fluid responsiveness in low tidal volume ventilated pigs

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2010
S. T. VISTISEN
Introduction: The respiratory variation in the pre-ejection period (,PEP) has been used to predict fluid responsiveness in mechanically ventilated patients. Recently, we automated this parameter and indexed it to tidal volume (PEPV) and showed that it was a reliable predictor for post-cardiac surgery, mainly paced, patients ventilated with low tidal volumes. The aims of the present animal study were to investigate PEPV's ability to predict fluid responsiveness under different fluid loading conditions and natural heart rates during low tidal volume ventilation (6 ml/kg) and to compare the performance of PEPV with other markers of fluid responsiveness. Methods: Eight prone, anesthetized piglets (23,27 kg) ventilated with tidal volumes of 6 ml/kg were subjected to a sequence of 25% hypovolemia, normovolemia, and 25% and 50% hypervolemia. PEPV, ,PEP, pulse pressure variation (PPV), central venous pressure (CVP), and pulmonary artery occlusion pressure (PAOP) were measured before each volume expansion. Results: Sensitivity was 89% and specificity was 93% for PEPV, 78% and 93% for ,PEP, 89% and 100% for PPV, 78% and 93% for CVP, and 89% and 87% for PAOP. Conclusion: PEPV predicts fluid responsiveness in low tidal volume ventilated piglets. [source]

Anaesthetic requirement and stress hormone responses in patients undergoing lumbar spine surgery: anterior vs. posterior approach

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2009
K. Y. YOO
Background: The intensity of nociceptive stimuli reflects the severity of tissue injury. The anaesthetic requirement and stress hormonal responses were determined to learn whether they differ according to different surgical approaches (anterior vs. posterior) during the spinal surgery. Methods: Patients undergoing lumbar spine surgery without neurological deficits were divided into two groups: one having posterior (n=13) and the other having anterior fusion (n=13). The end-tidal sevoflurane concentrations (ETSEVO) required to maintain the bispectral index score at 40,50 were determined. Mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum osmolality and plasma concentrations of catecholamines, cortisol and vasopressin (AVP) were measured. Results: There were no differences in MAP, HR, CVP and serum osmolality between the groups. ETSEVO was higher in the anterior than in the posterior group (P<0.05). The plasma concentrations of norepinephrine and cortisol increased in both groups during the surgery, whereas those of epinephrine remained unchanged. AVP concentrations increased during the surgery in the anterior group, and remained unaltered in the posterior group. The anterior group needed more analgesics (P<0.01) during the first 1 h after the operation. Conclusions: The anterior approach required a deeper level of anaesthesia while undergoing spinal surgery and more use of post-operative analgesics than the posterior approach. It was also associated with a more pronounced AVP release during the surgery. [source]

Association between central venous pressure and blood loss during hepatic resection in 984 living donors

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2009
Y. K. KIM
Background: Although low central venous pressure (CVP) anesthesia has been used to minimize blood loss during hepatectomy, the efficacy of this technique remains controversial. We therefore assessed the association between blood loss and CVP during hepatic resection, and examined significant determinants associated with intraoperative hemorrhage during hepatectomy in living donors. Methods: Between April 2004 and April 2008, 984 living donors who underwent a hepatic resection were assessed retrospectively. Univariate and multivariate analyses were performed to explore the relationships between intraoperative blood loss and several variables including CVP. Results: The mean intraoperative blood loss was 691.3 ± 365.5 ml. Only four donors required packed red blood cell transfusions (mean, 1.5 U). The mean duration of hepatic resection was 92.1 ± 26.3 min. The mean, maximum, and minimum values of CVP measured during hepatectomy were 4.6 ± 1.7, 5.3 ± 1.8, and 4.0 ± 1.8 mmHg, respectively, and were not significantly correlated with intraoperative blood loss. On multivariate analysis, predictors of hemorrhage were liver fatty change, gender, and body weight, but none of the mean CVP, surgeons, anesthesiologists, anesthesia duration, resected liver volume, hepatectomy type, systolic blood pressure, heart rate, or body temperature were significant. Conclusions: CVP during hepatic resection was not associated with intraoperative blood loss in living liver donors, suggesting that CVP may not be an important factor in predicting blood loss during hepatectomy in healthy subjects. [source]

Automated pre-ejection period variation indexed to tidal volume predicts fluid responsiveness after cardiac surgery

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2009
S. T. VISTISEN
Background: Reliable continuous monitoring of fluid responsiveness is an unsolved issue in patients ventilated with low tidal volume. We hypothesised that variations in the pre-ejection period (PEP) defined as the time interval between electrocardiogram (ECG) R-wave and onset of systolic upstroke in arterial blood pressure could reliably predict fluid responsiveness in patients ventilated with moderately low tidal volume. Furthermore, we hypothesised that indexing dynamic parameters to tidal volume would improve their prediction. The aim was to refine and automate a previously suggested algorithm for PEP variation (,PEP) and to test this new parameter indexed to tidal volume (PEPV), as a marker of fluid responsiveness along with central venous pressure (CVP), pulse pressure variation (PPV) and ,PEP. Additionally, the aim was to evaluate the concept of indexing dynamic parameters to tidal volume. Methods: Arterial pressure, CVP, ECG and cardiac index (CI) were acquired from 23 mechanically ventilated post-cardiac surgery patients scheduled for volume expansion. PEPV, PPV and ,PEP were extracted. Results: Using responder/non-responder classification (response=change in CI>+15%), sensitivity and specificity were 100% and 83%, respectively, for PEPV, 94% and 83% for ,PEP, and 94% and 83% for PPV. CVP offered no relevant information. Tidal volume indexing improved sensitivity for ,PEP to 100%. Conclusion: In this study in post-cardiac surgery patients, a refined parameter, PEPV, predicted fluid responsiveness better than PPV and ,PEP. Our results suggest that dynamic parameters using variations in PEP should be indexed to tidal volume. [source]

Cardiovascular effects of desflurane following acute hemorrhage in dogs

JOURNAL OF VETERINARY EMERGENCY AND CRITICAL CARE, Issue 1 2003
Paulo S.P. Santos DVM
Abstract Objective: To determine the cardiovascular effects of desflurane in dogs following acute hemorrhage. Design: Experimental study. Animals: Eight mix breed dogs. Interventions: Hemorrhage was induced by withdrawal of blood until mean arterial pressure (MAP) dropped to 60 mmHg in conscious dogs. Blood pressure was maintained at 60 mmHg for 1 hour by further removal or replacement of blood. Desflurane was delivered by facemask until endotracheal intubation could be performed and a desflurane expiratory end-tidal concentration of 10.5 V% was maintained. Measurements and main results: Systolic, diastolic, and mean arterial blood pressure (SAP, DAP and MAP), central venous pressure (CVP), cardiac output (CO), stroke volume (SV), cardiac index (CI), systemic vascular resistance (SVR), heart rate (HR), respiratory rate (RR), partial pressure of carbon dioxide in arterial blood (PaCO2), and arterial pH were recorded before and 60 minutes after hemorrhage, and 5, 15, 30, 45 and 60 minutes after intubation. Sixty minutes after hemorrhage, SAP, DAP, MAP, CVP, CO, CI, SV, PaCO2, and arterial pH decreased, and HR and RR increased when compared with baselines values. Immediately after intubation, MAP and arterial pH decreased, and PaCO2 increased. Fifteen minutes after intubation SAP, DAP, MAP, arterial pH, and SVR decreased. At 30 and 45 minutes, MAP and DAP remained decreased and PaCO2 increased, compared with values measured after hemorrhage. Arterial pH increased after 30 minutes of desflurane administration compared with values measured 5 minutes after intubation. Conclusions: Desflurane induced significant changes in blood pressure and arterial pH when administered to dogs following acute hemorrhage. [source]

Cardiovascular and Pulmonary Effects of Hetastarch Plus Hypertonic Saline Solutions during Experimental Endotoxemia in Anesthetized Horses

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 6 2006
DACVIM, Lucas G. Pantaleon MV
Background:Small volume resuscitation has been advocated as a beneficial therapy for endotoxemia in horses but this therapy has not been investigated in a prospective manner. The objective of this study was to determine the cardiopulmonary effects of small-volume resuscitation using hypertonic saline solution (HSS) plus Hetastarch (HES) during experimental endotoxemia in anesthetized horses. Hypothesis:Treatment of horses with induced endotoxemia using HES-HSS does not alter the response of various cardiopulmonary indices when compared to treatment with either small-or large-volume isotonic crystalloid solutions. Animals:Eighteen healthy horses were randomly assigned to 1 of 3 groups. Anesthesia was maintained with halothane. Endotoxemia was induced by administering 50 ,g/kg of Escherichia coli endotoxin IV. The horses were treated over 30 minutes with 15 mL/kg of balanced polyionic crystalloid solution (control), 60 mL/kg of balanced polyionic crystalloid solution (ISO), or 5 mL/kg of HSS followed by 10 mL/kg of HES (HSS-HES). Methods:Prospective randomized trial. Results:Cardiac output (CO) after endotoxin infusion increased significantly (P < .05) from baseline in all groups, whereas mean central venous pressure increased significantly (P < .05) in the ISO group only. Mean pulmonary artery pressure increased from baseline (P < .05) in horses treated with isotonic fluids and HSS-HES. There was no effect of treatment with HSS-HES on CO, systemic vascular resistance (SVR), mean arterial pressure, blood lactate concentrations, or arterial oxygenation. Conclusions and Clinical Importance: The use of HSS-HES failed to ameliorate the deleterious hemodynamic responses associated with endotoxemia in horses. The clinical value of this treatment in horses with endotoxemia remains unconfirmed. [source]

Respiration can be monitored by photoplethysmography with high sensitivity and specificity regardless of anaesthesia and ventilatory mode

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2005
L. Nilsson
Background:, Photoplethysmography (PPG) is a non-invasive optical technique used, for instance, in pulse oximetry. Beside the pulse synchronous component, PPG has a respiratory synchronous variation (PPGr). Efforts have been made to utilize this component for indirect monitoring of respiratory rate and volume. Assessment of the clinical usefulness as well as of the physiological background of PPGr is required. We evaluated if anaesthesia and positive-pressure ventilation would affect PPGr. Methods:, We recorded reflection mode PPGr, at the forearm, and the respiratory synchronous changes in central venous pressure (CVP), peripheral venous pressure (PVP) and arterial blood pressure (ABP) in 12 patients. Recordings for each patient were made on three occasions: awake with spontaneous breathing; anaesthetized with spontaneous breathing; and anaesthetized with positive-pressure ventilation. We analyzed the sensitivity, specificity, coherence and time relationship between the signals. Results:, PPGr sensitivity for breath detection was [mean (SD)] >86(21)% and specificity >96(12)%. Respiratory detection in the macrocirculation (CVP, PVP and ABP) showed a sensitivity >83(29)% and specificity >93(12)%. The coherence between signals was high (0.75,0.99). The three measurement situations did not significantly influence sensitivity, specificity or time shifts between the PPGr, PVP, ABP, and the reference CVP signal despite changes in physiological data between measurements. Conclusion:, A respiratory synchronous variation in PPG and all invasive pressure signals was detected. The reflection mode PPGr signal seemed to be a constant phenomenon related to respiration regardless of whether or not the subject was awake, anaesthetized or ventilated, which increases its clinical usefulness in respiratory monitoring. [source]

Haemodynamic changes during positive-pressure ventilation in children

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2005
A. Kardos
Background:, Positive-pressure ventilation may alter cardiac function. Our objective was to determine with the use of impedance cardiography (ICG) whether altering airway pressure modifies the central haemodynamics in mechanically ventilated children with no pulmonary pathology. Central venous saturation (ScvO2) was measured as an indicator of tissue perfusion. Methods:, Twelve children between 7 and 65 months of age, requiring mechanical ventilation as a consequence of a non-pulmonary disease, were enrolled in the study. All patients had a central venous line as a part of their routine management. Using pressure controlled ventilation (PCV) the baseline PEEP value of 5 cmH2O (Pb5) was increased to 10 cmH2O (Pi10) and then to 15 cmH2O (Pi15). After Pi15, PEEP was decreased to 10 (Pd10) and then to 5 cmH2O (Pd5). Each time period lasted 5 min heart rate (HR), mean arterial blood pressure (MABP), central venous pressure (CVP), end-tidal carbon dioxide (ETCO2), mean airway pressure (Paw), stroke volume index (SVI), cardiac index (CI) and central venous oxygen saturation (ScvO2) were recorded at the end of the five periods. Results:, The values of CI did not change when 10 and 15 cmH2O of PEEP were applied. Elevation of PEEP and thus Paw caused slight but not significant reductions in SVI and ScvO2 as compared to the baseline (Tb5). After reducing PEEP in Td5 we found statistically significant elevations of SVI and CI, as compared to Ti15 heart rate, ETCO2 and MABP remained unchanged. Conclusion:, We did not find significant haemodynamic changes following PEEP elevation in ventilated children, as measured using impedance cardiography. Reducing the value of PEEP to 5 cmH2O resulted in statistically significant SVI elevations. The values of ScvO2 remained unaffected. [source]

Dural haemorrhage in non-traumatic infant deaths: does it explain the bleeding in ,shaken baby syndrome'?

NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 1 2003
J. F. Geddes
J. F. Geddes, R. C. Tasker, A. K. Hackshaw, C. D. Nickols, G. G. W. Adams, H. L. Whitwell and I. Scheimberg (2003) Neuropathology and Applied Neurobiology 29, 14,22 Dural haemorrhage in non-traumatic infant deaths: does it explain the bleeding in ,shaken baby syndrome'? A histological review of dura mater taken from a post-mortem series of 50 paediatric cases aged up to 5 months revealed fresh bleeding in the dura in 36/50, the bleeding ranging from small perivascular haemorrhages to extensive haemorrhage which had ruptured onto the surface of the dura. Severe hypoxia had been documented clinically in 27 of the 36 cases (75%). In a similar review of three infants presenting with classical ,shaken baby syndrome', intradural haemorrhage was also found, in addition to subdural bleeding, and we believe that our findings may have relevance to the pathogenesis of some infantile subdural haemorrhage. Recent work has shown that, in a proportion of infants with fatal head injury, there is little traumatic brain damage and that the significant finding is craniocervical injury, which causes respiratory abnormalities, severe global hypoxia and brain swelling, with raised intracranial pressure. We propose that, in such infants, a combination of severe hypoxia, brain swelling and raised central venous pressure causes blood to leak from intracranial veins into the subdural space, and that the cause of the subdural bleeding in some cases of infant head injury is therefore not traumatic rupture of bridging veins, but a phenomenon of immaturity. Hypoxia with brain swelling would also account for retinal haemorrhages, and so provide a unified hypothesis for the clinical and neuropathological findings in cases of infant head injury, without impact or considerable force being necessary. [source]

Influence of endogenous angiotensin II on control of sympathetic nerve activity in human dehydration

THE JOURNAL OF PHYSIOLOGY, Issue 22 2009
J. A. Rabbitts
Arterial blood pressure can often fall too low during dehydration, leading to an increased incidence of orthostatic hypotension and syncope. Systemic sympathoexcitation and increases in volume regulatory hormones such as angiotensin II (AngII) may help to maintain arterial pressure in the face of decreased plasma volume. Our goals in the present study were to quantify muscle sympathetic nerve activity (MSNA) during dehydration (DEH), and to test the hypothesis that endogenous increases in AngII in DEH have a mechanistic role in DEH-associated sympathoexcitation. We studied 17 subjects on two separate study days: DEH induced by 24 h fluid restriction and a euhydrated (EUH) control day. MSNA was measured by microneurography at the peroneal nerve, and arterial blood pressure, electrocardiogram, and central venous pressure were also recorded continuously. Sequential nitroprusside and phenylephrine (modified Oxford test) were used to evaluate baroreflex control of MSNA. Losartan (angiotensin type 1 receptor (AT1) antagonist) was then administered and measurements were repeated. MSNA was elevated during DEH (42 ± 5 vs. EUH: 32 ± 4 bursts per 100 heartbeats, P= 0.02). Blockade of AT1 receptors partially reversed this change in MSNA during DEH while having no effect in the control EUH condition. The sensitivity of baroreflex control of MSNA was unchanged during DEH compared to EUH. We conclude that endogenous increases in AngII during DEH contribute to DEH-associated sympathoexcitation. [source]

Haemodynamic responses to exercise, ATP infusion and thigh compression in humans: insight into the role of muscle mechanisms on cardiovascular function

THE JOURNAL OF PHYSIOLOGY, Issue 9 2008
José González-Alonso
The muscle pump and muscle vasodilatory mechanims are thought to play important roles in increasing and maintaining muscle perfusion and cardiac output during exercise, but their actual contributions remain uncertain. To evaluate the role of the skeletal muscle pump and vasodilatation on cardiovascular function during exercise, we determined leg and systemic haemodynamic responses in healthy men during (1) incremental one-legged knee-extensor exercise, (2) step-wise femoral artery ATP infusion at rest, (3) passive exercise (n= 10), (4) femoral vein or artery ATP infusion (n= 6), and (5) cyclic thigh compressions at rest and during passive and voluntary exercise (n= 7). Incremental exercise resulted in progressive increases in leg blood flow (,LBF 7.4 ± 0.7 l min,1), cardiac output ( 8.7 ± 0.7 l min,1), mean arterial pressure (,MAP 51 ± 5 mmHg), and leg and systemic oxygen delivery and . Arterial ATP infusion resulted in similar increases in , LBF, and systemic and leg oxygen delivery, but central venous pressure and muscle metabolism remained unchanged and MAP was reduced. In contrast, femoral vein ATP infusion did not alter LBF, or MAP. Passive exercise also increased blood flow (,LBF 0.7 ± 0.1 l min,1), yet the increase in muscle and systemic perfusion, unrelated to elevations in aerobic metabolism, accounted only for ,5% of peak exercise hyperaemia. Likewise, thigh compressions alone or in combination with passive exercise increased blood flow (,LBF 0.5,0.7 l min,1) without altering , MAP or . These findings suggest that the skeletal muscle pump is not obligatory for sustaining venous return, central venous pressure, stroke volume and or maintaining muscle blood flow during one-legged exercise in humans. Further, its contribution to muscle and systemic peak exercise hyperaemia appears to be minimal in comparison to the effects of muscle vasodilatation. [source]

Low Central Venous Pressure with Milrinone During Living Donor Hepatectomy

CORPUS CAVERNOSUM AS AN ALTERNATIVE MEANS OF INTRAVENOUS ACCESS IN THE EMERGENCY SETTING

ANZ JOURNAL OF SURGERY, Issue 7 2000
D. Nicol
Background: The present study was designed to investigate the feasibility of using the corpus cavernosum as an alternative means of intravenous access in the emergency setting. Methods: The feasibility of achieving the infusion flow rates was first ascertained using direct intracavernous infusion of normal saline. The effect of atropine and adrenaline when given via this route was then studied. Hypovolaemic shock was then induced in dogs who were then actively resuscitated via this route using normal saline, Haemaccel and whole blood. Results: Infusion flow rates were achieved for normal saline of 32.3, 50.3 and 67.3 mL per min at 100, 200 and 300 mmHg pressure, respectively. The peak effects of atropine and adrenaline via this route were seen at approximately 1 min after injection. Resuscitation using this method was uniformly successful in all dogs via the corpus cavernosum, with all reaching or exceeding their premorbid central venous pressure (CVP), and approaching or reaching their premorbid mean arterial pressure (MAP). In comparison the control dog's CVP and MAP did not rise during the period of observation after it was bled. Conclusions: The corpus cavernosum is a practical alternative means of intravenous access in the emergency setting in the dog model. [source]

Hemodynamic Changes in a Model of Chronic Heart Failure Induced by Multiple Sequential Coronary Microembolization in Sheep

ARTIFICIAL ORGANS, Issue 11 2009
Jan Dieter Schmitto
Abstract Although a large variety of animal models for acute ischemia and acute heart failure exist, valuable models for studies on the effect of ventricular assist devices in chronic heart failure are scarce. We established a stable and reproducible animal model of chronic heart failure in sheep and aimed to investigate the hemodynamic changes of this animal model of chronic heart failure in sheep. In five sheep (n = 5, 77 ± 2 kg), chronic heart failure was induced under flouroscopic guidance by multiple sequential microembolization through bolus injection of polysterol microspheres (90 µm, n = 25.000) into the left main coronary artery. Coronary microembolization (CME) was repeated up to three times in 2 to 3-week intervals until animals started to develop stable signs of heart failure. During each operation, hemodynamic monitoring was performed through implantation of central venous catheter (central venous pressure [CVP]), arterial pressure line (mean arterial pressure [MAP]), implantation of a right heart catheter {Swan-Ganz catheter (mean pulmonary arterial pressure [PAPmean])}, pulmonary capillary wedge pressure (PCWP), and cardiac output [CO]) as well as pre- and postoperative clinical investigations. All animals were followed for 3 months after first microembolization and then sacrificed for histological examination. All animals developed clinical signs of heart failure as indicated by increased heart rate (HR) at rest (68 ± 4 bpm [base] to 93 ± 5 bpm [3 mo][P < 0.05]), increased respiratory rate (RR) at rest (28 ± 5 [base] to 38 ± 7 [3 mo][P < 0.05]), and increased body weight 77 ± 2 kg to 81 ± 2 kg (P < 0.05) due to pleural effusion, peripheral edema, and ascites. Hemodynamic signs of heart failure were revealed as indicated by increase of HR, RR, CVP, PAP, and PCWP as well as a decrease of CO, stroke volume, and MAP 3 months after the first CME. Multiple sequential intracoronary microembolization can effectively induce myocardial dysfunction with clinical and hemodynamic signs of chronic ischemic cardiomyopathy. The present model may be suitable in experimental work on heart failure and left ventricular assist devices, for example, for studying the impact of mechanical unloading, mechanisms of recovery, and reverse remodeling. [source]

Resolution of protein-losing enteropathy after radiofrequency perforation and subsequent stent implantation for relief of complete occlusion of a redirected left superior vena cava

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2006
Rainer Schaeffler MD
Abstract The application of radiofrequency (RF) technologies in the treatment of congenital heart defects has provided a safe and effective alternative to conventional therapies in the restoration of vascular patency for a variety of arterial and venous occlusions. This report concerns an 8-year old girl that developed protein-losing enteropathy and elevated central venous pressure after occlusion of a surgically redirected anomalous draining left superior vena cava (SVC). Cardiac catheterization revealed complete obstruction of the anastomosis of the SVC into the coronary sinus. Transcatheter recanalization by RF perforation and subsequent stent implantation led to the restoration of upper venous blood flow and the resolution of her symptoms. © 2006 Wiley-Liss, Inc. [source]

Haemodynamic action of B-type natriuretic peptide substantially outlasts its plasma half-life in conscious dogs

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2003
Colleen J Thomas
Summary 1.,The objective of the present study was to determine the plasma half-life of B-type natriuretic peptide (BNP) in conscious dogs after intravenous administration and to compare this with its haemodynamic effects. In six chronically instrumented dogs, plasma BNP concentrations were measured under basal conditions, during a constant infusion of canine BNP-32 (10 pmol/kg per min; 25 min) to steady state and at nominated time points up to 75 min after stopping the infusion. Concomitant, continuous measurements of mean arterial blood pressure (MAP), heart rate (HR), central venous pressure (CVP) and mesenteric blood flow (MBF) were obtained. 2.,Baseline plasma BNP levels were 15.0 ± 2.3 fmol/mL and rose approximately 10-fold to 159 ± 23 fmol/mL after 20,25 min BNP infusion. When the infusion was turned off, plasma BNP levels declined in a biphasic manner, with an initial half-life of 1.57 ± 0.14 min and a terminal half-life of 301 ± 85 min. The metabolic clearance rate of BNP was 2.29 ± 0.34 L/min. 3.,The infusion of BNP reduced MAP (approximately 10%), CVP (approximately 65%) and MBF (approximately 25%), whereas haematocrit (approximately 4%) and mesenteric vascular resistance (MVR) increased (approximately 40%; all P < 0.05). Plasma BNP levels returned to baseline by 20 min after BNP infusion had been stopped, whereas none of the haemodynamic variables returned to normal by this time. Mean arterial pressure returned to resting levels within 10,15 min after plasma BNP returned to normal. However, CVP, haematocrit and MBF remained substantially below baseline values for more than 20 min after circulating BNP levels had returned to pre-infusion levels. Of these, only mesenteric vascular changes were returned to baseline within 60 min of plasma BNP levels normalizing. 4.,These results demonstrate that the removal of BNP from the canine circulation is rapid, similar to observations made regarding the metabolism of circulating atrial natriuretic peptide in dogs. The half-life of BNP in dogs was shorter than that in rats, sheep or humans. However, the haemodynamic actions of BNP substantially outlasted its plasma half-life. Whether this disparity in plasma level and haemodynamic activity of BNP reflects long-lasting activation of second messenger systems or slow recovery from the hydraulic changes at the capillary level, reflected in the haematocrit and CVP, remains to be answered. [source]

Hemodynamic profile and tissular oxygenation in orthotopic liver transplantation: Influence of hepatic artery or portal vein revascularization of the graft

LIVER TRANSPLANTATION, Issue 11 2006
Carlos Moreno
We performed a prospective, randomized study of adult patients undergoing orthotopic liver transplantation, comparing hemodynamic and tissular oxygenation during reperfusion of the graft. In 30 patients, revascularization was started through the hepatic artery (i.e., initial arterial revascularization) and 10 minutes later the portal vein was unclamped; in 30 others, revascularization was started through the portal vein (i.e., initial portal revascularization) and 10 minutes later the hepatic artery was unclamped. The primary endpoints of the study were mean systemic arterial pressure and the gastric-end-tidal carbon dioxide partial pressure (PCO2) difference. The secondary endpoints were other hemodynamic and metabolic data. The pattern of the hemodynamic parameters and tissue oxygenation values during the dissection and anhepatic stages were similar in both groups At the first unclamping, initial portal revascularization produced higher values of mean pulmonary pressure (25 ± 7 mm of Hg vs. 17 ± 4 mm of Hg; P < 0.05) and wedge and central venous pressures. At the second unclamping, initial portal revascularization produced higher values of cardiac output and mean arterial pressure (87 ± 15 mm of Hg vs. 79 ± 15 mm of Hg; P < 0.05) and pulmonary blood pressure. Postreperfusion syndrome was present in 13 patients (42.5%) in the arterial group and in 11 patients (36%) in the portal group. During revascularization, the values of gastric and arterial pH decreased in both groups and recovered at the end of the procedure, but were more accentuated in the initial arterial revascularization group. In conclusion, we found that initial arterial revascularization of the graft increases pulmonary pressure less markedly, so it may be indicated for those patients with poor pulmonary and cardiac reserve. Nevertheless, for the remaining patients, initial portal revascularization offers more favorable hemodynamic and metabolic behavior, less inotropic drug use, and earlier normalization of lactate and pH values. Liver Transpl, 2006. © 2006 AASLD. [source]

Comparison of external jugular and central venous pressures in patients undergoing repair of proximal femoral fractures

ANAESTHESIA, Issue 10 2002
C. M. Allsager
No abstract is available for this article. [source]

Hemodynamic Effects of Intravenous Fat Emulsion in an Animal Model of Severe Verapamil Toxicity Resuscitated with Atropine, Calcium, and Saline

ACADEMIC EMERGENCY MEDICINE, Issue 2 2007
Theodore C. Bania MD
Background Intravenous fat emulsion (IFE) decreases cardiotoxicity from several lipid-soluble drugs, including verapamil. Objectives To verify if the addition of IFE to the standard treatment of severe verapamil toxicity would improve hemodynamics and survival. Methods Fourteen dogs were instrumented to measure systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), heart rate, cardiac output, central venous pressures, left ventricular pressure changes over time, mixed venous oxygen saturation, pH, and base excess. Verapamil toxicity, defined as a 50% decrease in MAP, was induced with verapamil at 6 mg/kg/hr and maintained for 30 minutes by titrating the verapamil infusion rate. Following verapamil toxicity, the verapamil infusion rate was changed to 2 mg/kg/hr and continued for 90 minutes. All dogs were resuscitated with atropine (0.04 mg/kg intravenously) and calcium chloride (15 mg/kg intravenously every 5 minutes for three doses) and then randomized to receive either IFE (7 mg/kg of 20%) intravenously or equivalent volumes of 0.9% normal saline over 30 minutes. Measurements were recorded for 120 minutes by investigators blinded to the treatment. Data were analyzed using analysis of variance, survival analysis, and log-rank test. Results Before the 30-minute IFE or normal saline infusion, there were no differences in hemodynamic parameters. After IFE or normal saline infusion, the IFE-treated group had higher MAP at 30 minutes (95% confidence interval [CI] = 5.6 to 44.7 mm Hg), 45 minutes (95% CI = 10.8 to 50.0 mm Hg), and 60 minutes (95% CI = 10.2 to 53.1 mm Hg). Kaplan,Meier 120-minute survival rate was 14% (95% CI = 0.5% to 53%) for the saline group as compared with 100% (95% CI = 59% to 100%) for the IFE group (p = 0.01). Conclusions Standard resuscitation and IFE increase MAP and survival in an animal model of severe verapamil toxicity compared with standard resuscitation alone. [source]