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At least 991 records · Page 55Linked to original sources
PubMed1999

Hemodynamic effects of methylprednisolone in patients undergoing cardiac operation and early extubation.

BACKGROUND: Whether or not methylprednisolone is beneficial during cardiac operation remains controversial. This study examines the effects of the drug on complement activation and hemodynamics in patients undergoing cardiac operation and early extubation. METHODS: Patients undergoing cardiac operation were randomized to receive either intravenous methylprednisolone (group MP) or intravenous placebo (group NS). Complement 3a (C3a) levels and hemodynamic parameters were obtained perioperatively. Extubation was accomplished at the earliest clinically appropriate time. RESULTS: Both groups exhibited equivalent increases in C3a levels after exposure to bypass. Group MP exhibited increased cardiac index, decreased systemic vascular resistance, and increased shunt flow when compared to group NS. More group MP patients required hemodynamic support and group MP patients had prolonged extubation times. CONCLUSIONS: Methylprednisolone was unable to attenuate complement activation and led to hemodynamic alterations (primarily vasodilation) that may hinder early extubation in patients after cardiac operations.

Adult↗
PubMed1999

Vascular delay of the latissimus dorsi provides an early hemodynamic benefit in dynamic cardiomyoplasty.

OBJECTIVES: Dynamic cardiomyoplasty (CMP) as a surgical treatment for chronic heart failure improves functional class status for most patients. However, significant hemodynamic improvement with latissimus dorsi muscle (LDM) stimulation has not been consistent. The current protocols do not allow early LDM stimulation after CMP surgery. We hypothesized that vascular delay of LDM would increase myocardial assistance after CMP and allow early (48-h) LDM stimulation after CMP. METHODS: Mongrel dogs (n = 24) were divided in four groups: 1) controls (n = 6), single-stage CMP; 2) Group ES (n = 6), single-stage CMP with early LDM stimulation beginning 48 h, postoperatively; 3) Group VD (n = 6), vascular delay of the LDM followed by CMP without early LDM stimulation, and 4) Group VDES (n = 6), vascular delay of LDM (14-18 days), followed by CMP with early stimulation (48 h postoperatively). Two weeks after CMP, global cardiac dysfunction was induced by injecting microspheres into the left coronary artery. LDM-assisted (S) beats were compared with nonstimulated beats (NS) by measuring aortic pressure (AoP), LV pressure, aortic flow, and by calculating first derivative of LV contraction (+/-dP/dt), stroke volume (SV), and stroke work (SW). RESULTS: In ES, LDM stimulation had no effect on the hemodynamic parameters. In the other groups, LDM stimulation significantly (p < 0.05) increased AoP, LVP, dP/dt, SV, and SW. However, these increases were much larger in VD and VDES. In VD, LDM stimulation increased peak AoP by 21.5+/-3.8 mm Hg, LVP by 22.1+/-4.1 mm Hg, dP/dt by 512+/-163 mm Hg/sec, SV by 10.4+/-2.3 mL, and SW by 22.1+/-5.4 g/m(-1). Similarly, in VDES, LDM stimulation increased peak AoP by 24.1+/-4.7 mm Hg, LVP by 26.2+/-4.3 mm Hg, dP/dt by 619+/-47 mm Hg/sec, SV by 6.5+/-0.7 mL, and SW by 16.7+/-4.1 g/m(-1). CONCLUSIONS: In dogs with global LV dysfunction, CMP after vascular delay resulted in a significant improvement in hemodynamic function measured 2 weeks after surgery. This improvement was not provided by single-stage CMP with or without early stimulation. Vascular delay of the LDM before surgery may play an important role for early benefit after CMP, shorten the overall muscle training period, as well as increase hemodynamic response to LDM stimulation.

Animals↗
PubMed1999

Cardiopulmonary bypass and oxygen consumption: oxygen delivery and hemodynamics.

BACKGROUND: This study was undertaken to investigate the relations between whole body oxygen consumption (VO2), oxygen delivery (DO2), and hemodynamic variables during cardiopulmonary bypass. METHODS: One hundred one patients were studied during cooling, hypothermia, and rewarming. Oxygen consumption, DO2, hemodynamics, and DO2crit were measured at these times. RESULTS: There was a direct linear relation between DO2 and VO2 during all three times. No relation between VO2 and hemodynamics was detected during cooling; during hypothermia, an inverse linear relation with peripheral arterial resistance was found. Finally, during rewarming, there was a direct relation with pump flow rate, and an inverse relation with arterial pressure and arterial resistance. The same relations among the variables were found at delivery levels above or below DO2crit. CONCLUSIONS: During cardiopulmonary bypass there is a direct linear relation between DO2 and VO2; the relations with hemodynamic variables depend on the phases of cardiopulmonary bypass. This suggests that increasing delivery levels may recruit and perfuse more vascular beds, and higher delivery levels are advisable during perfusion. During rewarming and hypothermia, lower arterial resistances are also desirable to optimize VO2.

Aged↗
PubMed1999

Less invasive, continuous hemodynamic monitoring during minimally invasive coronary surgery.

BACKGROUND: Minimally invasive coronary surgery has gained more and more clinical acceptance. A clear contrast to the minimally invasive idea is the highly invasive pulmonary artery catheter used for hemodynamic monitoring during the operation. We evaluated a less invasive device which calculates cardiac output (CO) and hemodynamics based on arterial pulse-contour analysis. METHODS: In 20 patients revascularized by the off-pump technique with the octopus system, agreement of CO by pulse-contour was compared to pulmonary arterial and femoral arterial thermodilution and hemodynamic alterations during the operation were recorded. Pulse-contour CO is computed by measuring the area under the arterial pressure waveform and dividing it by aortic impedance. Aortic impedance is determined by an arterial thermodilution at the onset of the system. RESULTS: Correlation of pulmonary arterial and arterial thermodilution CO to pulse-contour CO was 0.91 and 0.90 respectively (both p<0.01). Coefficients of variations were 6.2% and 6.7%. The bias was 0.1 L per minute and standard deviations were 0.42 L per minute and 0.55 L per minute. Hemodynamic changes during the operations were seen mainly during the distal anastomosis of the first diagonal branch; only slight changes occurred during the anastomosis of the left anterior descending coronary artery. CONCLUSIONS: Arterial pulse-contour analysis is easy to use and minimally invasive, thus qualifies as a reliable routine monitoring tool during minimally invasive coronary surgery with tissue stabilizers.

Aged↗
PubMed2003

Acute hemodynamic effects of abdominal exercise with and without breath holding.

OBJECTIVES: To compare the magnitudes of change in heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure, and rate-pressure product (RPP) during 3 abdominal exercises: straight partial sit-up (SPSU), oblique partial sit-up (OPSU), and the AbSculptor(R) sit-up; and to examine the effect of breath holding on these parameters. DESIGN: Prospective, repeated measures. SETTING: Autonomic research laboratory in a major medical center. PARTICIPANTS: Fourteen normal male and female volunteers (age range, 24-37y; mean, 30.4y). INTERVENTIONS: Hemodynamic parameters were recorded during each abdominal exercise performed with and without breath holding. Mean peak values were calculated for 1 minute before exercise, during exercise, and for 10 minutes after exercise. MAIN OUTCOME MEASURES: Statistical analysis examined for differences in the hemodynamic changes among the 3 exercises under both conditions (with and without breath holding). RESULTS: Heart rate, SBP, DBP, mean blood pressure, and RPP increased during all 3 exercises. The mean peak heart rate and RPP increases were greater for the OPSU than the AbSculptor (heart-rate increase, 21.1+/-6.6bpm vs 17.6+/-5.7bpm, P=.03; RPP increase, 36.9+/-15.5bpm.mmHg vs 29.4+/-10.1bpm.mmHg, P=.05). For all 3 exercises, breath holding significantly increased the hemodynamic parameter elevations during exercise, with the exception of heart rate (SBP, P<.001; DBP, P<.001; mean blood pressure, P<.001; RPP, P=.02). Quantitatively, breath holding during the OPSU resulted in the largest exercise-associated increases in heart rate (21.0+/-8.1bpm), mean blood pressure (22.2+/-16.4mmHg), and RPP (44.9+/-22.3bpm.mmHg). Postexercise, all hemodynamic parameters generally returned to baseline within several minutes. CONCLUSION: When performing the OPSU, SPSU, or the AbSculptor exercises as used in this investigation, normal individuals exercising at low intensities may experience peak heart rate and mean blood pressure increases of 30bpm and 50mmHg, respectively. Voluntary breath holding significantly increased the peak blood pressure elevations and RPP for all 3 exercises, but particularly for the OPSU.

Abdomen↗
PubMed2001

Central corticotropin releasing factor (CRF) and adrenergic receptors mediate hemodynamic responses to cocaine.

Cocaine administration evokes cardiovascular responses that are variable in rats such that the pressor response is attributable to either a large increase in systemic vascular resistance and a decrease in cardiac output (vascular responders) or a smaller increase in systemic vascular resistance and no change or an increase in cardiac output (mixed responders). This study was designed to determine the role of central corticotropin releasing factor (CRF) and adrenergic receptors in mediating specific hemodynamic response patterns. Rats were instrumented for ascending aortic blood flow determination (cardiac output) using a pulsed Doppler system, arterial pressure measurement and for intravenous and intracerebroventricular (icv) administration of drugs. After characterizing the hemodynamic response pattern in individual rats to cocaine (5 mg/kg, i.v., 4-6 trials), selective receptor antagonists were administered icv 10 min before cocaine (5 mg/kg, i.v.). Pretreatment with the CRF antagonist alpha-helical CRF(9-41) (10 microg/5 microl, icv) prevented the decrease in cardiac output in vascular responders without altering hemodynamic responses to cocaine in mixed responders. Astressin (5 microg/5 microl, icv) exerted a similar effect in vascular responders. The alpha(2) receptor antagonist, yohimbine (3 microg/microl, icv) also prevented the decrease in cardiac output in vascular responders. Lower doses of alpha-helical CRF(9-41) (1 and 3 microg) were ineffective whereas higher doses of either CRF antagonist were lethal within 24 h. In contrast, propranolol (3 or 30 microg, icv) pretreatment enhanced the cocaine-induced decrease in cardiac output and increase in systemic vascular resistance noted in vascular responders and resulted in a decrease in cardiac output in mixed responders. We conclude that CRF and adrenoceptors in the CNS play an important role in determining the hemodynamic response pattern to cocaine. Furthermore, central beta-adrenoceptors may be responsible for the reported effects of intravenous propranolol on cocaine-induced responses.

Adrenergic beta-Antagonists↗
PubMed2003

Post-ischemic myocardial fibrosis occurs independent of hemodynamic changes.

OBJECTIVES: Myocardial fibrosis is a major component of ventricular remodeling after large myocardial infarction (MI). The present study tests the hypothesis that post-ischemic myocardial fibrosis can occur independent of hemodynamic changes. METHODS: A mouse model of distal left coronary artery ligation was established to induce a small infarct (less than 15% of the left ventricle) in order to avoid significant mechanical overload after permanent myocardial ischemia. Left heart catheterization was performed to evaluate the post-infarct hemodynamics. Tissues from both ischemic and non-ischemic myocardium were examined for mRNA and protein expression at 24, 72 h and 7 days after ligation. RESULTS: Heart/body weight ratio after ligation was increased by approximately 10% over sham control although there is no statistically significant difference in hemodynamic parameters between the two groups. Non-ischemic myocardium distant from the infarct site showed molecular evidence of myocardial fibrosis 72 h and 7 days after ligation. There was marked up-regulation of mRNAs for extracellular matrix (ECM) proteins and their cross-linking enzyme, such as collagens type I, III and VI, and lysyl oxidase. Immunohistochemical study confirmed that the expression of these ECM proteins was significantly increased in the non-ischemic myocardium after 7 days. TGF-beta1 was up-regulated after 72 h in both ischemic and non-ischemic myocardium. CONCLUSIONS: Molecular and histopathological findings demonstrate that abnormal myocardial fibrosis can be induced by a small infarct independent of secondary hemodynamic changes.

Animals↗
PubMed2000

Relationship between left ventricular mass and hemodynamic responses to physical and mental stress.

OBJECTIVE: Increased left ventricular mass (LVM) is predictive of future cardiac morbidity and mortality. Although casual and ambulatory blood pressure (BP) predict LVM, other hemodynamic determinants of LVM are incompletely understood. The present study examines laboratory-induced hemodynamic responses (to exercise, cold, and mental stress) and 24-hour ambulatory measures as predictors of LVM. METHODS: Thirty-six healthy non-hypertensive subjects (mean age 33.9 +/- 9.4 years; 23 women, 13 men) were tested with mental stress, cold pressor, and treadmill exercise in the laboratory and 24-hour ambulatory BP monitoring. LVM was measured using two-dimensional targeted M-mode echocardiography and indexed for body surface area (LVMI). RESULTS: All laboratory tasks produced significant hemodynamic responses (p's < 0.01). Systolic blood pressure responses to mental stress (r = 0.42, p < 0.01) and cold pressor (r = 0.34, p < 0.05) were significantly related to LVM. After adjusting for body size, the mental stress-induced SBP responses was the only significant predictor of LVMI (r = 0.32, p < 0.05). Exercise SBP responses were associated to LVMI in men (r = 0.63, p = 0.02), but not in women (r = 0.02, p = n.s.). Multivariate regression analyses revealed that SBP during mental stress was significantly predictive of LVMI (beta = 0.65, p = 0.05), independent of baseline SBP, 24-hour ambulatory SBP, and other control variables. CONCLUSION: The present results indicate that SBP responses to mental stress are significantly related to LVM among healthy individuals, independently of baseline SBP, 24-hour ambulatory BP, age, body size, and sex. Blood pressure responses to exercise show a robust association with LVM in men but not in women. Hemodynamic responses elicited during laboratory tasks may therefore reveal important information about the pathophysiological processes involved in the development of cardiac end-organ damage.

Adaptation, Psychological↗
PubMed2000

Pulmonary hemodynamics contribute to indicate priority for lung transplantation in patients with cystic fibrosis.

OBJECTIVE: Lung transplantation is a viable option for patients with cystic fibrosis. The current strategy of selection, based on spirometry and deterioration of quality of life, results in a high mortality on the waiting list. We reviewed the case histories of patients with cystic fibrosis accepted for lung transplantation to ascertain whether pulmonary hemodynamics could contribute to predict life expectancy. METHODS: Forty-five patients with cystic fibrosis were accepted: 11 died on the waiting list (group I), 24 underwent transplantation (group II), and 10 are still waiting (group III). During evaluation we recorded spirometry, oxygen requirement, ratio of arterial oxygen tension to inspired oxygen fraction (PaO (2)/FIO (2)), arterial carbon dioxide tension (PaCO (2)), 6-minute walk test results, right ventricular ejection fraction, echocardiography, and pulmonary hemodynamics. We compared data from group I, II, and III patients. A comparison was also made within group II between the data collected at the time of evaluation and at the time of transplantation to quantify the deterioration during the waiting time. RESULTS: The waiting time, spirometry, 6-minute walk test results, and right ventricular ejection fraction did not differ among the three groups. A statistically significant difference was found for PaO (2)/FIO (2), PaCO (2), mean pulmonary artery pressure, cardiac index, pulmonary arterial wedge pressure, and intrapulmonary shunt between groups I and II. Groups I and III showed statistically significant differences for mean pulmonary artery pressure, PaO (2)/FIO (2), and systemic vascular resistance indexed. No differences were observed between groups II and III. The comparison within group II showed a significant deterioration of pulmonary hemodynamics during the waiting time. CONCLUSIONS: Pulmonary hemodynamics are worst in patients dying on the waiting list and deteriorate significantly during the waiting time. They may thus contribute to establish priority for lung transplantation in patients with cystic fibrosis.

Adolescent↗
PubMed1996

Diffuse veno-occlusive dysfunction: the underlying hemodynamic abnormality resulting in failure to respond to intracavernous pharmacotherapy.

PURPOSE: We established hemodynamic predictors of response to intracavernous pharmacotherapy. MATERIALS AND METHODS: Specific characterization and quantification of hemodynamic abnormalities of the cavernous arterial inflow and corporeal veno-occlusive mechanism associated with failure to respond to intracavernous pharmacotherapy were performed retrospectively in 69 patients with nonendocrinological impotence. We investigated atherosclerotic vascular risk factors, duplex ultrasonography peak systolic and end diastolic velocities (10 micrograms. prostaglandin E1), and dynamic infusion cavernosometry and cavernosography parameters (60 mg. papaverine and 6 mg. phentolamine). RESULTS: The patients were stratified by severity of the various hemodynamic parameters encountered and mean dose required for response. Response subsequently was characterized as excellent (75% or greater rigid erections) in 36 patients, adequate (erections sufficient for intromission) in 17 and poor or absent in 16. Psychogenic, neurogenic and mild vasculogenic causes were noted in patients with an excellent response. The adequate responses included all 3 cases with mild to moderate vascular etiologies whereas patients with a poor or no response had only severe venogenic and combined arteriogenic and venogenic etiologies. Mean flow-to-maintain values plus or minus standard deviation of 9.7 +/- 3.7, 10.8 +/- 9.5 and 59.5 +/- 24.2 ml. per minute were demonstrated in the excellent, adequate and poor or no response groups, respectively. There was a good correlation between mean flow-to-maintain values and mean doses of our standard vasoactive solution (r2 = 0.88, p < 0.0001). Pharmaco-cavernosography demonstrated diffuse or pan-cavernous corporeal veno-occlusive dysfunction in the poor or no response group. CONCLUSIONS: Corporeal veno-occlusive dysfunction alone or combined with arterial disease is the specific hemodynamic abnormality causing nonresponse to intracavernous pharmacotherapy. Diffuse drainage, particularly involving the glans penis and corpus spongiosum, is greatly predictive of a poor or no response, reflecting the underlying cavernous smooth muscle myopathy and collagen degenerative alterations in these patients with end-organ failure.

Adult↗
PubMed1992

The hemodynamic pathophysiology of impotence following blunt trauma to the erect penis.

A total of 19 patients provided a history of impotence following blunt trauma to the erect penis during intercourse or masturbation, or after accidents. Corporeal veno-occlusive dysfunction was the most common hemodynamic abnormality (16 of 19 patients, or 84%). A site-specific leak, which consisted of abrupt filling of the dorsal vein and/or corpus spongiosum from a focal site on the penile shaft, was demonstrated in 15 patients (79%). Cavernous artery insufficiency was found less often (7 of 19 patients, or 37%). A focal mid shaft cavernous artery occlusion was demonstrated in 5 patients (28%). It is hypothesized that the aforementioned hemodynamic abnormalities are caused by tunica and intracavernous vasculature injuries induced by the marked short-term pressure increases, which approach or exceed the tunica tensile strength during acute abrupt loading of the erect penis. This hypothesis is supported by direct recording of intracavernous pressures that exceeded 450 mm. Hg in response to angulation and manual compression of the penile shaft. Further evidence was created by a biomechanical model that was based on previously published intracavernous pressure--circumference patient data during dynamic infusion pharmacocavernosometry. Using a typical patient data set a 60% diminution of circumference at the site of abrupt loading was calculated to induce a 15% increase in circumference in the nonloaded portion of the penile shaft and an elevated intracavernous pressure exceeding 900 mm. Hg. The site-specific hemodynamic abnormalities were found to occur not only in patients with a classical penile fracture history but also in patients with injuries during masturbation or following accidents who had no acute penile swelling or ecchymosis. Thus, the erect penis is at risk for injury during any acute loading situation. It is likely that this erect trauma-induced hemodynamic pathology occurs more frequently than previously appreciated and that this type of impotence may be the underlying basis for many cases of idiopathic Peyronie's disease.

Adolescent↗
PubMed1997

Hemodynamic effects of isovolemic hemodilution during descending thoracic aortic cross clamping and lower torso reperfusion.

BACKGROUND: Isovolemic hemodilution has been suggested for blood conservation and to improve hemodynamic tolerance to abdominal aortic cross clamping. However, the hemodynamic effects of hemodilution during descending thoracic aortic cross clamping (DAC) have not been established. We evaluated them in anesthetized swine. METHODS: Hemodilution (n = 7) was produced by the isovolemic exchange of blood for 6% hetastarch to a target hematocrit of 20%. Hematocrit in control pigs (n = 7) remained at 30%. DAC was performed at the T9 level for 45 minutes. During a 60-minute reperfusion period, control pigs were infused with lactated Ringer's solution; shed blood was returned to hemodilution pigs, followed by lactated Ringer's. If hypotension occurred despite left atrial pressure of 10 mm Hg or greater, boluses of phenylephrine were given to keep mean arterial pressure above 60 mm Hg. RESULTS: Hemodilution caused a marked reduction in hematocrit and in global oxygen delivery (DO2). DAC produced a significant increase in proximal arterial pressure, cardiac index, and DO2 and oxygen consumption (VO2) was markedly reduced in both groups. A significant increase in systemic vascular resistance during DAC occurred only in control pigs. After reperfusion, vascular resistance was significantly lower than baseline in hemodilution pigs, requiring a sixfold greater dose of phenylephrine to avoid hypotension. A lower global DO2 and supply-limited VO2 were also observed in hemodilution pigs. CONCLUSIONS: Isovolemic hemodilution maintains hemodynamic stability during DAC. During lower torso reperfusion, however, hemodilution caused hemodynamic instability, decreased global DO2, and limited VO2, which may offset its potential benefits.

Animals↗
PubMed1997

Influence of continuous hemofiltration on the hemodynamics of trauma patients.

BACKGROUND: The aim of this prospective randomized controlled study was to investigate the effects of continuous venovenous hemofiltration on the hemodynamics and respiratory function of critically ill trauma patients with multiple organ dysfunction syndrome. METHODS: Thirty consecutive critically ill, mechanically ventilated, trauma patients with multiple organ dysfunction syndrome (without kidney failure) who had invasive hemodynamic monitoring for management of hypotension or hypoxemia were randomized to treatment with or without continuous venovenous hemofiltration. Hemodynamics profile was recorded immediately before and at 6, 12, 24, and 48 hours after the hemofiltration was started (mean of three set data each time). No changes in ventilatory parameters were performed during the study. RESULTS: Thirty patients were analyzed (15 with and 15 without hemofiltration). Both groups were similar in age (36 +/- 18 versus 36 +/- 14 years) and severity scores (Injury Severity Score, 32 +/- 16 versus 30 +/- 11; Acute Physiology and Chronic Health Evaluation II score, 22 +/- 7 versus 21 +/- 6; Goris score, 5.2 +/- 1.7 versus 5.2 +/- 1.8) and received similar inotropic support. We found a significant improvement in mean arterial pressure (80 +/- 9 to 94 +/- 8 (mm Hg), p = 0.01) and partial pressure of oxygen in arterial blood/inspiratory oxygen supply index (124 +/- 40 to 204 +/- 44, p = 0.03) in the intervention group during the study period. We did not find any other significant change in variables studied. CONCLUSIONS: Continuous venovenous hemofiltration is associated with a significant improvement in hemodynamic and respiratory variables in critically ill trauma patients with multiple organ dysfunction syndrome. This improvement can help in the management of these patients. Further work is necessary to define whether this technique can reduce the high mortality of this disease.

Adult↗
PubMed2000

Hemodynamics of in-tandem stenosis of the internal carotid artery: when is carotid endarterectomy indicated?

BACKGROUND: Recent publications have pointed out the importance of evaluating patients with in-tandem stenosis and in particular the association of moderate stenosis of the extracranial internal carotid artery (ICA) with moderate or severe stenosis of the intracranial internal carotid artery. Such evaluations are needed in symptomatic patients before planning carotid endarterectomies because observations have shown that in some cases the removal of an extracranial lesion does not necessarily improve these symptoms. This paper examines the hemodynamic effects of in-tandem stenosis in the internal carotid artery. METHODS: Equations describing flow in arteries are modified to accommodate two regions of stenosis in tandem. An equivalent value of stenosis is derived such that two stenoses in tandem behave as a single stenosis with similar hemodynamic properties. The solution to this problem is solved mathematically and this was used to analyze the observations made in five studies published on in-tandem stenosis of the internal carotid artery. RESULTS: Equivalent stenoses for various values of extracranial and intracranial stenoses are presented. It was found that two stenotic lesions in tandem are not equivalent to a simple summation of both values. A graphical solution is presented to show the hemodynamic effects of both stenoses. CONCLUSIONS: The most critical determinant of hemodynamic compromise when two lesions are in tandem is the larger one. Hence removal of a more proximal lesion may have little effect on a larger distal lesion if the symptoms are due to hypoperfusion. It is important that one distinguish between hypoperfusion and thromboembolic causes of the symptoms. No conclusions about the risk of thromboembolic events after a carotid endarterectomy in the setting of a distal stenosis can be made from this study.

Aged↗
PubMed1996

Circulating neuropeptide Y in humans: relation to changes in catecholamine levels and changes in hemodynamics.

Neuropeptide-Y (NPY) is a sympathetic cotransmitter, which causes vasoconstriction, decreases coronary blood flow and decreases cardiac output. Circulating immunoreactive NPY (ir-NPY) levels increase with exercise, in patients admitted to the coronary care unit, and during thoracic surgery, and may play a role in postoperative hemodynamics. We studied changes in ir-NPY, epinephrine (E) and norepinephrine (NE) arterial plasma levels, and their correlation to simultaneous hemodynamic measurements at 8 perioperative time points in 13 patients undergoing open heart surgery. Changes in circulating ir-NPY negatively correlated with changes in systemic vascular resistance index (SVRI), mean arterial pressure (MAP) and mean pulmonary arterial pressure (MPAP) (P < 0.05), suggesting that the hemodynamic changes were the cause of the changes in ir-NPY levels, inducing overflow of NPY into the circulation via sympathetic activation. Changes in NE and E levels positively correlated with changes in heart rate (HR), SVRI and MPAP. Changes in E levels also positively correlated with changes in stroke volume index (SVI), central venous pressure (CVP) and cardiac index (CI). NE levels correlated well with E levels, but catecholamine levels did not correlate with ir-NPY levels. These results suggest, that the elevation in circulating NPY levels previously noted in patients with heart failure and acute myocardial infarction may reflect changes in NPY overflow and/or clearance secondary to increased sympathetic activity and to hemodynamic changes.

Blood Pressure↗
PubMed2003

Systemic and regional hemodynamics in pre-ascitic cirrhosis: effects of posture.

BACKGROUND/AIMS: To clarify the hemodynamic pattern of pre-ascitic cirrhosis, we compared the impact of posture on systemic and regional hemodynamics of patients and healthy subjects without and with plasma volume expansion. METHODS: Cardiac index (CI), peripheral vascular resistance (PVRi), heart rate, mean arterial pressure, and the mean blood flow velocities of superior mesenteric (SMAV) and common femoral arteries were evaluated by duplex-Doppler techniques in 10 patients and 20 healthy controls after 2 h of standing and 2 h after lying down. Ten healthy controls received saline infusion (15 ml/kg body weight) when they changed their posture, and five were also evaluated after plasma volume expansion in the upright posture. RESULTS: Standing systemic and regional hemodynamics did not differ between patients and controls. After saline infusion, standing control subjects showed greater CI and SMAV than patients. Recumbency caused changes of CI, PVRi and SMAV greater in patients and controls with plasma expansion than in controls without expansion, so that supine patients and controls with expansion were indistinguishable, showing higher CI and SMAV and lower PVRi than controls without expansion. CONCLUSIONS: Systemic and regional hemodynamics of patients with pre-ascitic cirrhosis are mainly determined by blood volume expansion which is compartmentalized within the splanchnic venous bed during standing and translocates towards the central and arterial circulatory districts during recumbency.

Adult↗
PubMed1997

Acute effects of propylthiouracil on hemodynamics and oxygen content in patients with alcoholic cirrhosis.

BACKGROUND/AIMS: The antithyroid drug propylthiouracil has been suggested for the treatment of alcoholic liver disease. Its beneficial effects could be due to either a decrease in hepatic oxygen consumption or an increase in hepatic blood flow. The aim of this study was to test these two hypotheses in patients with proven alcoholic cirrhosis. METHODS: The pharmacokinetic parameters after intravenous administration of 300 mg of propylthiouracyl were first determined in four patients. Then, the effects on systemic and splanchnic hemodynamics, and oxygen content were measured 45 and 90 min after the intravenous administration of 300 mg (n=6) or 600 mg (n=6) of propylthiouracil. RESULTS: Systemic hemodynamics (heart rate, arterial pressure, cardiac output and systemic vascular resistance) and splanchnic hemodynamics (hepatic venous pressure gradient, hepatic and azygos blood flows) were not modified 45 and 90 min after the administration of 300 mg or 600 mg of propylthiouracil. Moreover, neither oxygen content in the radial artery, pulmonary artery or hepatic vein, nor systemic oxygen uptake was modified after propylthiouracyl administration. The absence of effect of propylthiouracyl administration was also confirmed in patients with cirrhosis with proven acute alcoholic hepatitis (n=7). CONCLUSIONS: In patients with alcoholic cirrhosis, acute administration of propylthiouracyl has no effect on systemic and splanchnic hemodynamics or on oxygen contents. The presence of acute alcoholic hepatitis does not modify these results.

Adult↗
PubMed1993

Hemodynamic monitoring during CPR.

Real-time hemodynamic monitoring provides useful information that can be used to assess and optimize mechanical and pharmacological interventions during CPR. The standard algorithms should always be the initial approach to resuscitation, because they offer a rapid, logical, coordinated series of treatments with proven success. Pressure and flow measurements during conventional, closed-chest CPR in humans indicate that the technique typically produces a hemodynamic state resembling profound cardiogenic shock, with a low systemic arterial pressure, markedly reduced cardiac output, and high intravascular filling pressures. End-tidal carbon dioxide monitoring provides useful, noninvasive information during clinical resuscitation. A low end-tidal carbon dioxide value during resuscitation should alert the rescuers that something is wrong with ventilation, perfusion, and/or carbon dioxide production and should prompt a search for correctable causes. If one or more hemodynamic parameters are being monitored at the time the patient develops cardiac arrest (eg, an intensive care unit patient who has an arterial line and a pulmonary artery catheter in place), it is appropriate for the resuscitation team to pay attention to the data that are generated during the resuscitation, particularly if the initial algorithm approach is not successful. For patients who are not being monitored at the time of their arrest, end-tidal carbon dioxide measurements provide noninvasive, semiquantitative information that can help the team detect and troubleshoot problems during resuscitation. Further research and better, more affordable technologies are needed to provide in- and out-of-hospital resuscitation teams feedback on the hemodynamic effectiveness of their resuscitative efforts.

Animals↗