Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HEMODYNAMICS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,171 records · Page 65Linked to original sources
PubMed2006

A comparative study between the effects of 4% endotracheal tube cuff lignocaine and 1.5 mg/kg intravenous lignocaine on coughing and hemodynamics during extubation in neurosurgical patients: a randomized controlled double-blind trial.

A prospective, randomized double-blind trial was performed to compare the effects of 4% endotracheal tube cuff lignocaine and 1.5 mg/kg intravenous (IV) lignocaine on coughing and hemodynamics during extubation in patients undergoing elective craniotomies in supine position. Forty-one patients received 4% lignocaine into the endotracheal tube cuff after intubation (ETT group) and 41 patients received IV lignocaine at 1.5 mg/kg before extubation (IV group). Coughing was assessed by a scale of 3 at the time of extubation. Hemodynamic parameters recorded at 1-minute interval after extubation for 5 minutes were compared with the baseline values recorded before skin closure. Results showed that there was no significant difference between the groups in terms of coughing or the hemodynamic response to tracheal extubation. In conclusion, 4% endotracheal tube cuff lignocaine was not superior to 1.5 mg/kg IV lignocaine in attenuating coughing and hemodynamic changes during extubation.

Administration, Topical↗
PubMed1997

The influence of heat shock protein 70 induction on hemodynamic variables in a porcine model of recurrent endotoxemia.

The manipulation of stress gene expression by heavy metals provides protection against the lethal effects of endotoxemia in murine models of septic shock. These findings suggest that the increased resistance to endotoxin in vivo after stress protein induction could be explained by an attenuation of hemodynamic alterations and an altered pattern of inflammatory mediator release. Therefore, we measured main hemodynamic variables such as systemic and pulmonary artery pressure, cardiac output, heart rate, central venous pressure, and pulmonary artery wedge pressure, as well as the time-course of thromboxane-B2, 6-keto-PGF1 alpha, and interleukin 6 formation with and without induction of the stress response in an established porcine model of recurrent endotoxemia (Circ Shock 35:237-244, 1991). Induction of the stress response was carried out by a pretreatment with Zn2+ (25 mg/kg zinc-bis-(DL-hydrogenaspartate) = 5 mg/kg Zn2+). Pretreatment with Zn2+ prior to lipopolysaccharide (LPS) infusion induced an increased heat shock protein 70 (HSP70) expression in the lungs, liver, and kidneys and significantly increased plasma levels of interleukin 6, 6-keto-PGF1 alpha, and thromboxane-B2, compared with untreated controls. After LPS infusion, however, pretreated animals showed significantly decreased peak plasma levels of all mediators compared with the untreated group. Hemodynamic data presented significantly decreased peak pulmonary artery pressure and pulmonary vascular resistance index values, significantly increased systemic artery pressure and systemic vascular resistance index values, and significantly altered hypodynamic/hyperdynamic cardiac output levels in the pretreated group. In conclusion, the data show that the induction of HSP70 by Zn2+ attenuates the liberation of inflammatory mediators, as well as the course of hemodynamic variables due to LPS.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Circulating endothelin and nitrate-nitrite relate to hemodynamic and metabolic variables in human septic shock.

Activation of the nitric oxide (NO) pathway over that of endothelin in the vessel wall, as judged from circulating endothelin and nitrate-nitrite (NN) levels, may partly account for the hypotension associated with vasodilation, diminished catecholamine sensitiveness and O2 extraction, and lactic acidemia in human septic shock. In a prospective study, 14 consecutive patients with septic shock and a pulmonary artery catheter in place were included. For 3 days after admission, serial measurements of hemodynamic variables and plasma levels of endothelin and NN were done. The patients had a hyperdynamic circulation. Except for a higher final blood lactate level and more treatment with vasoconstricting catecholamines in nonsurvivors, global hemodynamic and O2-related variables did not differ between outcome groups. On the day of admission, circulating endothelin and NN levels were elevated and related to elevated levels of tumor necrosis factor-alpha and interleukin-6. The levels of endothelin increased in time in nonsurvivors as compared with survivors. The NN levels declined in survivors but not in nonsurvivors. The systemic vascular resistance indices (SVRI), global O2 extraction ratios, and blood lactate levels directly related to the endothelin levels. SVRI and global O2 extraction ratios inversely, and the lactate blood levels directly, related to NN levels, and the hemodynamic and metabolic parameters related directly to the ratio between endothelin and NN plasma levels on the days of the study. The vessel wall factors did not relate to the creatinine levels. The results suggest that the hemodynamic and metabolic peripheral abnormalities of human septic shock are mediated in part by cytokine-activated endothelin and NO systems in the vessel wall. They also suggest that increased production rather than diminished renal clearance accounts for elevated levels of NN and endothelin and that the latter are associated with a poor outcome.

Adult↗
PubMedDate not supplied

Comparison of hemodynamic and biochemical effects of furosemide by continuous infusion and intermittent bolus in critically ill patients.

Positive fluid balance in critically ill patients is a common problem in the intensive care unit (ICU) often associated with a poor outcome. In addition, clinically important changes in hemodynamic variables have been found to occur after diuretic therapy. This study was conducted to evaluate the safety and relative effectiveness of two diuretic protocols in the ICU. Twenty-two patients in the medical ICU with pulmonary edema or fluid overload and PaO2/FIO2 pressure less than 300, were randomized to diuretic therapy by either continuous infusion or intermittent bolus. Hemodynamic and biochemical measurements were recorded. Protocol-guided diuretic management can be readily and safely implemented in the ICU. Although both continuous and bolus diuretic regimens appear to be equally effective in achieving negative fluid balance, the clinician may consider a continuous infusion of furosemide in the hemodynamically and electrolytically unstable patient to ensure more controlled diuresis with less hemodynamic and electrolyte alteration. From a nursing perspective, a continuous infusion of furosemide is a more efficient means of drug delivery.

Analysis of Variance↗
PubMed2004

Practice parameters for hemodynamic support of sepsis in adult patients: 2004 update.

OBJECTIVE: To provide the American College of Critical Care Medicine with updated guidelines for hemodynamic support of adult patients with sepsis. DATA SOURCE: Publications relevant to hemodynamic support of septic patients were obtained from the medical literature, supplemented by the expertise and experience of members of an international task force convened from the membership of the Society of Critical Care Medicine. STUDY SELECTION: Both human studies and relevant animal studies were considered. DATA SYNTHESIS: The experts articles reviewed the literature and classified the strength of evidence of human studies according to study design and scientific value. Recommendations were drafted and graded levels based on an evidence-based rating system described in the text. The recommendations were debated, and the task force chairman modified the document until <10% of the experts disagreed with the recommendations. CONCLUSIONS: An organized approach to the hemodynamic support of sepsis was formulated. The fundamental principle is that clinicians using hemodynamic therapies should define specific goals and end points, titrate therapies to those end points, and evaluate the results of their interventions on an ongoing basis by monitoring a combination of variables of global and regional perfusion. Using this approach, specific recommendations for fluid resuscitation, vasopressor therapy, and inotropic therapy of septic in adult patients were promulgated.

Adult↗
PubMed2006

Hemodynamic monitoring in obese patients: the impact of body mass index on cardiac output and stroke volume.

OBJECTIVE: Interpreting hemodynamic parameters in critically ill obese patients can be difficult as the effects of body mass index (BMI) on cardiac output (CO) and stroke volume (SV) at the extremes of body size remains unknown. We examined the relationship between BMI and both CO and SV for patients with varying body sizes. DESIGN: Retrospective cohort analysis. SETTING: A large tertiary care academic medical center. PATIENTS: A total of 700 consecutive adults who were found to have disease-free coronary arteries and a cardiac output measurement (thermodilution or Fick method) during coronary angiography between July 1, 2000, and July 31, 2004. MEASUREMENTS AND RESULTS: We examined the relationship between BMI (mean, 28 kg/m(2); range, 10.6-91.6 kg/m(2)) and cardiac hemodynamics after adjusting for demographic (age, sex) and clinical (diabetes, smoking status, valvular heart disease, medications, indications for catheterization) characteristics using multivariable regression. Body mass index was positively correlated with CO and SV. Each 1 kg/m increase in BMI was associated with a 0.08 L/min (95% confidence interval [CI], 0.06-0.10; p < .001) increase in CO and 1.35 mL (95% CI, 0.96-1.74; p < .001) increase in SV. There was no significant association between BMI and both cardiac index (0.003 L/min/m(2); 95% CI, -0.008-0.014; p = .571) and stroke volume index (0.17 mL/m(2); 95% CI, -0.03-0.37; p = .094). CONCLUSION: Variations in BMI translate into predictable but only modest differences in CO and SV, even at the extremes of body size. Indexing hemodynamic measurements to body surface area attenuates the effects of BMI. Body habitus should not appreciably complicate the interpretation of hemodynamic measurements.

Aged↗
PubMed2006

Reliability of a noninvasive device to measure systemic hemodynamics in hemodialysis patients.

OBJECTIVE: To evaluate the reliability of a noninvasive hemodynamic monitor in hemodialysis patients. METHODS: We enrolled 15 male patients (mean age 63+/-12 years) on stable chronic hemodialysis. Blood pressure and hemodynamic readings were obtained with the Dynapulse 500 Guardian device (Pulsemetric Inc., San Diego, California, USA), which measures systemic hemodynamics on the basis of oscillometric waveforms obtained through a cuff placed over the brachial artery. Measurements were taken sequentially, in duplicate, before, during and after hemodialysis, in the supine, seated and standing positions on four separate midweek dialysis sessions over a 2-week period. RESULTS: The repeatability of the method was tested using 200 pairs of valid measurements. The average values (+/-SD) were 137+/-22 mmHg for systolic blood pressure, 80+/-13 mmHg for diastolic blood pressure, 76+/-15 bpm for heart rate, 1320+/-268 mmHg/s for dP/dtmax, 2.8+/-0.5 l/min/m for cardiac index, and 1455+/-359 dyn/s/cm for systemic vascular resistance. The mean differences (+/-SD of the difference) between readings were 0.1+/-10.4 mmHg for systolic blood pressure, 0.3+/-6.0 mmHg for diastolic blood pressure, -0.2+/-8.0 bpm for heart rate, 0.2+/-234 mmHg/s for dP/dtmax, 0.03+/-0.26 l/min/m for cardiac index and -10+/-177 for systemic vascular resistance, yielding limits of agreement (95%) of -20 to 20 mmHg for systolic blood pressure, -11 to 12 mmHg for diastolic blood pressure, -16 to 17 bpm for heart rate, -458 to 458 mmHg/s for dP/dtmax, -0.5 to 0.5 l/min/m for cardiac index and -338 to 357 dyn/s/cm for systemic vascular resistance. Other hemodynamic parameters fared similarly, and coefficients of variation were all between 7 and 18%. CONCLUSION: We conclude that the Dynapulse 500 Guardian has adequate reliability indices in hemodialysis patients.

Aged↗
PubMed2006

Timing of fluid resuscitation shapes the hemodynamic response to uncontrolled hemorrhage: analysis using dynamic modeling.

BACKGROUND: Timing of fluid resuscitation with respect to intrinsic hemostasis is an unexplored aspect of uncontrolled hemorrhage, because most animal models do not allow direct monitoring of blood loss. The aim of this study was to define how timing of crystalloid administration affects the bleeding patient's hemodynamic response to fluids, using a computer model of blood volume changes during uncontrolled hemorrhage. METHODS: A multi-compartment lumped-parameter deterministic model of intravascular volume changes in a bleeding adult patient was developed and implemented. The model incorporates empirical mathematical descriptions of intrinsic hemostasis and rebleeding. RESULTS: The predicted hemodynamic response to uncontrolled hemorrhage closely corresponds to that seen in animal studies. A 2-L crystalloid bolus given during ongoing hemorrhage increases blood loss by 4 to 29%, an effect that is inversely related to the initial bleeding rate. A similar bolus given after intrinsic hemostasis may trigger rebleeding if given when the hemostatic clot is mechanically vulnerable. This period of clot vulnerability (ranging from 0-34 minutes) changes with both the initial bleeding rate and the rate of fluid administration. CONCLUSIONS: The timing of crystalloid administration with respect to intrinsic hemostasis shapes the bleeding patient's hemodynamic response. An early bolus delays hemostasis and increases blood loss, while a late bolus may trigger rebleeding. These observations provide valuable insight into the hemodynamic response to fluid resuscitation.

Adult↗
PubMed1991

Hemodynamic and catecholamine responses to laryngoscopy with vs. without endotracheal intubation.

To study the relationship between the intensity of the stimulus exerted against the base of the tongue during direct laryngoscopy and the magnitude of associated hemodynamic and catecholamine responses, a study was conducted in 40 ASA I or II patients. Laryngoscopy lasting 40 s was performed with a size 3 Macintosh blade connected to a force-displacement transducer. The intensity of the stimulus exerted during laryngoscopy is expressed by the product of its average force (N) and duration (s) and given as impulse in Ns. Highly significant relationships were found between the impulse during laryngoscopy and the maximal hemodynamic and catecholamine responses. Also, when laryngoscopy was followed by orotracheal intubation, significant relationships were found with steeper slopes of the regression lines for systolic blood pressure, heart rate and plasma epinephrine concentrations. A more rapid regression of hemodynamic data was seen in intubated patients, whereas their plasma catecholamine concentrations regressed more slowly. The mechanisms of the responses to laryngoscopy and orotracheal intubation are proposed to be by somato-visceral reflexes. Stimulation of proprioceptors at the base of the tongue during laryngoscopy induces impulse-dependent increases of systemic blood pressure, heart rate and plasma catecholamine concentrations. Subsequent orotracheal intubation recruits additional receptors that elicit augmented hemodynamic and epinephrine responses as well as some vagal inhibition of the heart.

Adult↗
PubMed1991

Hemodynamic effect of the prone position during anesthesia.

We studied 21 patients undergoing lumbar spinal surgery under halothane anesthesia on a convex saddle frame, in order to determine the hemodynamic effect of the prone position. A thermodilution pulmonary arterial catheter was placed in 14 patients (Group PA-1: n = 8; and Group PA-2: n = 6), and an inferior vena caval catheter in the remaining seven patients (Group IVC). Group PA-1 and Group IVC patients were placed in the prone position on a convex saddle frame. In the prone position, the cardiac index (CI) decreased significantly from 3.1 +/- 0.5 to 2.5 +/- 0.3 (l.min-1.m-2, mean +/- s.d., P less than 0.01) without accompanying significant changes in the other hemodynamic variables in Group PA-1. The postural change in Group IVC did not exert a significant effect on the inferior vena caval pressure. Group PA-2 were initially placed in the flat prone position on a flat saddle frame, which produced no significant changes in the hemodynamic variables. Then the convex curvature of the frame was adjusted to the grade appropriate for surgery, which produced a significant reduction in CI (from 2.9 +/- 0.3 to 2.4 +/- 0.4, P less than 0.05). We conclude that the prone position itself may not interfere with the circulatory function. The prone position using a convex saddle frame causes significant reductions in CI, but little change in the other hemodynamic variables.

Anesthesia, Inhalation↗
PubMed1993

Hemodynamic changes associated with thermodilution cardiac output determination in canine acute blood loss or endotoxemia.

Since the technique of thermodilution (TD) cardiac output measurement, per se, causes hemodynamic alterations, the author examined whether the alterations elicited by iced injectate are augmented in the presence of acute blood loss or endotoxemia, compromised conditions frequently associated with critically ill patients. Acute blood loss (N = 8) and endotoxemia (N = 8) were induced by withdrawing arterial blood approximately 20-30 ml.kg-1 over 30 min and by a slow intravenous infusion of E. coli endotoxin 2.5-3.0 mg.kg-1 over 10 min, respectively, in anesthetized dogs. The magnitudes of decreases in mean arterial and pulmonary artery pressures during slowing of heart rate (HR) following injection of iced injectate 3 ml were slightly less in acute blood loss than in normovolemia, whereas in endotoxemia the degree of mean arterial pressure decrease during slowing of HR following iced injectate 3 ml was slightly less as compared with that before endotoxemia. However, the alterations in other hemodynamic variables following injection of iced injectate 3 ml were similar between dogs with and without acute blood loss or endotoxemia. No profound hemodynamic changes were observed during any TD cardiac output measurements under both conditions. Cardiac output estimated by TD correlated closely with pulmonary blood flow measured by electromagnetic flowmeter in endotoxemia (r > 0.9) but not during acute blood loss. These results indicate that TD cardiac output determination does not cause serious hemodynamic alterations in endotoxemia or acute blood loss, and can estimate right ventricular output accurately in endotoxemia but not in acute blood loss.

Acidosis↗
PubMed1995

Hemodynamic predictors of atrial fibrillation or flutter after coronary artery bypass grafting.

The cumulated incidence of atrial fibrillation or flutter after coronary artery bypass grafting is 30%. The causes of these arrhythmias have not yet been sufficiently identified. We therefore undertook the present study to analyze the possible association of hemodynamic function during the various phases of coronary artery bypass grafting and the later development of atrial fibrillation/flutter. Hemodynamic function was measured with a pulmonary artery catheter in 120 consecutive patients undergoing elective coronary artery bypass surgery. Thirty-five (29%) of the patients developed atrial fibrillation/flutter. Logistic regression analysis identified independent predictors of atrial fibrillation/flutter. After induction of general anesthesia, the relative risk (95% confidence interval) of older age was 1.09/year (1.03-1.16), and the reduction in relative risk by an increase in left ventricular stroke work was 0.96/gm (0.93-0.99). After weaning from the extracorporeal circulation the independent significant predictors were age, relative risk 1.07/year (1.01-1.13), and increased central venous pressure, relative risk 1.12/mm Hg (1.00-1.26). At the time of admission to the intensive care unit, the relative risk of age was 1.10/year (1.03-1.18), and the relative risk of an increased central venous pressure was 1.26/mm Hg (1.06-1.49). However, the best prediction model (prediction after induction of general anesthesia) only provided a median predicted probability of atrial fibrillation/flutter of 0.37 for the patients who had atrial fibrillation/flutter, and a median predicted probability of atrial fibrillation/flutter of 0.20 for the patients without these arrhythmias. We identified possible hemodynamic predictors of atrial fibrillation/flutter after coronary bypass surgery, but the use of a risk stratification for development of atrial fibrillation/flutter based on hemodynamic function cannot be recommended.

Age Factors↗
PubMed1997

Hemodynamic and coronary vascular effects of dexmedetomidine in the anesthetized goat.

BACKGROUND: In phase III trials, the hemodynamic stabilising effect of the alpha 2-adrenergic agonist dexmedetomidine (DEX) is being investigated in patients with coronary artery disease, Coronary vascular effects of alpha 2-agonists have been studied in dogs and pigs, but both species have a different hemodynamic response to DEX than man. The aim of this study was to investigate the hemodynamic and coronary vascular effects in goats. METHODS: In 6 open-chest goats anesthetized with halothane, central and coronary hemodynamics and oxygen supply and demand were measured before and following IV bolus infusion of DEX in doses ranging from 0.1 to 10 micrograms/kg. RESULTS: With DEX doses of 1 microgram/kg or higher, mean arterial pressure (MAP), systemic vascular resistance, coronary vascular resistance and arterio-mixed venous oxygen content increased within 2 min, but returned to baseline within 15 min. In contrast, there was a progressive and cumulative decrease in cardiac output (CO), heart rate, and dP/dtmax, Regional coronary venous oxygen extraction (C(a-cv)O2) transiently increased after 3 micrograms/kg DEX and decreased 15 min after 10 micrograms/kg DEX. LVEDP transiently increased after 3 and 10 micrograms/kg DEX. The changes after DEX 10 micrograms/kg differed from those after lower doses: MAP (35%), CO (50%), stroke volume (33%), C(a-cv)O2 (15%) and myocardial oxygen extraction (33%) were all decreased. Myocardial oxygen supply and demand decreased in parallel. CONCLUSIONS: 1) The cardiovascular response to IV DEX in goats is similar to man. 2) In goats after DEX, systemic and coronary vasoconstriction are short-lived, and 3) the balance between myocardial oxygen supply and demand is maintained.

Adrenergic alpha-Agonists↗
PubMed2006

The electrocardiographic and hemodynamic effect of metohexital and propofol with and without esmolol.

BACKGROUND: Metohexital and propofol are short-acting induction agents, which have a tendency to prolong the QTc interval of the ECG. We studied whether this increase could be prevented by combining a beta-blocking agent, esmolol, with these drugs. Simultaneously, we studied the hemodynamic effects of these combinations. METHODS: In a randomized, double-blind study, 80 ASA I-II young adults were premedicated with oxycodone and atropin and allocated to one of four groups: propofol (P), propofol + esmolol (P + E), metohexital (E) or metohexital + esmolol (M + E). The doses were 2 mg/kg propofol/metohexital and 1 mg/kg esmolol. Alfentanil 15 microg/kg was used in all groups. The hemodynamic parameters were measured non-invasively and the electrocardiographic parameters using the signal processing method. RESULT: The highest QTc values, which often exceeded the normal upper limit of 440 ms, were recorded at the baseline or immediately after the administration of the induction drugs. The intervals were significantly shorter if esmolol was co-administered with either propofol or metohexital. The heart rate increased in the group M and decreased in the group P + E but remained unchanged in the groups P and M + E. Systolic and diastolic arterial pressures decreased during the study in all groups, most prominently in group P + E. CONCLUSIONS: During the anesthesia induction, the QTc interval was significantly shorter when esmolol was co-administered with either propofol or metohexital. The hemodynamic responses were properly controlled with the combination of metohexital and esmolol as well as with propofol alone, but the combination of propofol and esmolol tended to cause hemodynamic depression.

Adolescent↗
PubMed2005

Effects of somatostatin, terlipressin and somatostatin plus terlipressin on portal and systemic hemodynamics and renal sodium excretion in patients with cirrhosis.

BACKGROUND AND AIM: Terlipressin and somatostatin are the most preferable agents for the control of variceal bleeding in cirrhotic patients. The present study evaluated the hemodynamic effects of somatostatin, terlipressin and somatostatin plus terlipressin in cirrhotic patients with portal hypertension, as well as the effect of each regimen on renal sodium excretion. METHODS: Twenty-four patients with esophageal varices were randomly assigned to receive either an intravenous infusion of a placebo (n = 12) or somatostatin 250 microg/h after an initial bolus of 250 microg (n = 12) for 60 min. Thereafter, each patient received an intravenous injection of terlipressin 2 mg while the intravenous infusion of either somatostatin or placebo was maintained. Portal and systemic hemodynamic parameters, assessed by Doppler sonography, and urinary sodium excretion were evaluated at baseline, 60 min after placebo or somatostatin, and 30 min after terlipressin. RESULTS: Placebo had no effect on the patients studied. After terlipressin, portal vein velocity, portal flow volume and cardiac output (CO) significantly decreased (0.09 vs 0.15 m/s, 0.56 vs 1 L/min and 6.4 vs 7.6 L/min, respectively [values are medians]), while mean arterial pressure (MAP) and systemic vascular resistance significantly increased (103.3 vs 89.9 mmHg and 1541 vs 1108dyn.s/cm(5), respectively). Fractional sodium excretion significantly increased in patients without ascites (0.43 vs 0.16%) while it did not change in patients with ascites. Somatostatin did not alter portal hemodynamics whereas it significantly reduced MAP, heart rate (HR) and CO (86.9 vs 98.6 mmHg, 65 vs 73 bpm and 8.4 vs 9.1 L/min, respectively) and, in patients with ascites, sodium excretion (0.13 vs 0.23%). The addition of terlipressin to somatostatin induced similar changes to those observed after terlipressin alone. The magnitude of increase in MAP was significantly higher in patients receiving terlipressin alone than in those receiving somatostatin plus terlipressin (15 vs 5.3%), while CO was conversely affected (-28.5 vs-20.9%). CONCLUSIONS: Combined treatment with somatostatin and terlipressin does not exert an additive portal hypotensive effect in cirrhotic patients as compared to terlipressin alone, whereas somatostatin alone may impair systemic hemodynamics. Compared with somatostatin, terlipressin exerts a more beneficial effect on renal sodium excretion in patients with or without ascites.

Antihypertensive Agents↗
PubMed2006

A comparative study of hemodynamic responses to orotracheal intubation with fiberoptic bronchoscope and laryngoscope in children.

BACKGROUND: The purposes of this study were to further identify the hemodynamic responses to orotracheal intubation in children, using a fiberoptic bronchoscope (FOB) and a direct laryngoscope (DLS), and to validate whether the FOB can attenuate the hemodynamic response to orotracheal intubation compared with the DLS. METHODS: Forty-three children, ASA PS I-II scheduled for elective plastic surgery under general anesthesia requiring orotracheal intubation were randomly allocated to either the DLS group (n = 20) or the FOB group (n = 23). Noninvasive systolic blood pressure (SBP) and heart rate (HR) were recorded before (baseline values) and after anesthesia induction (postinduction values), at intubation and every minute for the first 5 min after intubation. The maximal values of SBP and HR during the observation were also recorded. The product of HR and SBP [rate pressure product (RPP)] at each time point was calculated. RESULTS: In the DLS group, SBP, HR, and RPP at intubation and 1 min after intubation were significantly higher than postinduction values, but did not exceed baseline values. In the FOB group, SBP, HR, and RPP at intubation increased significantly compared with baseline and postinduction values. In the two groups, the maximal values of SBP, HR, and RPP during the observation were significantly higher than baseline values. Except for the HR at intubation, there were no significant differences in other hemodynamic parameters during the observation and the time required to reach maximal values of SBP, HR, and RPP between the two groups. CONCLUSIONS: Orotracheal intubation using FOB and DLS in children may cause similar increases in SBP and HR. Compared with the DLS, the FOB had no advantage in attenuating the hemodynamic responses to orotracheal intubation.

Anesthesia, General↗
PubMed1994

Systemic, regional and cerebral hemodynamic effects of a new angiotensin converting enzyme inhibitor, imidapril, in healthy volunteers.

The effects of two single oral doses (5 mg and 20 mg) of a new angiotensin I-converting enzyme inhibitor, imidapril, on a) systemic hemodynamics (arterial pressure, heart rate, cardiac output), b) brachial and common carotid arteries' hemodynamics (diameter and blood flow, pulsed Doppler technique), c) cerebral hemodynamics (middle cerebral artery mean blood flow velocity, transcranial Doppler technique), and d) biological parameters (plasma converting enzyme activity, active plasma renin, plasma aldosterone, catecholamines, and atrial natriuretic factor) were investigated and compared with those of a placebo during the 24 h period following administration in a randomized, double-blind, cross-over study performed in six healthy volunteers. Imidapril induced a strong, dose-dependent and sustained inhibition of plasma converting enzyme activity and at the 20 mg an increase in active plasma renin. Other investigated biological parameters were not drug-affected. Imidapril, whatever the dose, did not significantly affect systemic hemodynamic parameters. Imidapril, 20 mg, significantly increased common carotid artery blood flow and diameter and brachial artery diameter. Brachial blood flow also tended to increase but this was not significant. The middle cerebral artery mean blood flow velocity investigated in only five volunteers, underwent spontaneous variations after placebo, and these variations were not affected by imidapril, suggesting that imidapril, whatever the dose, does not influence cerebral blood flow. Thus, imidapril's vasodilating properties apparently affect only the muscular (brachial artery) and cutaneous (external carotid artery) territories, but do not influence the cerebral vascular bed.

Administration, Oral↗
PubMed1999

The hemodynamic effects of diltiazem in the isolated perfused rat liver are Ca(2+)-dependent.

AIMS/BACKGROUND: Diltiazem reduces systemic blood pressure by decreasing the vascular smooth muscle tone. In the liver however, diltiazem seems to cause vasoconstriction, as evidenced by increases in portal pressure. The questions raised by this observation are concerned with a) the site of action of diltiazem (large vessels or sinusoids), b) the formation of permeability barriers and c) the role of Ca2+. The experiments in the present study should provide an answer to these questions. METHODS: The experimental system was the hemoglobin-free perfused rat liver. The multiple-indicator dilution technique was employed with simultaneous injection of [14C]sucrose and [3H]water. Mean transit times and distribution spaces were calculated from the normalized outflow profiles. RESULTS: Calcium alone did not affect the hemodynamics of the liver. Diltiazem, however, changed several hemodynamic parameters when Ca2+ was present, but it was inactive in the absence of this cation. The hemodynamic effects of 500 microM diltiazem were: a) diminution of the transit time through the large vessels (t(o)) and, consequently, of the accessible vascular space (66.9%); b) diminution of the mean transit time of [14C]sucrose (tsuc) and, consequently, of the accessible sinusoidal space (28.1%); c) diminution of the mean transit time of tritiated water (twater) and, consequently, of the accessible cellular space (68.9%); d) diminution of the cellular to extracellular space ratio (theta) from 1.42 +/- 0.05 to 0.46 +/- 0.11. CONCLUSIONS: The linear superposition of the tritiated water and labeled sucrose curves, predicted by Goresky's model, could be optimized even when the curves were obtained with diltiazem + Ca2+, indicating that the distribution of both tracers was still flow-limited. The hemodynamic effects of diltiazem seem to be restricted to a vasoconstriction of the great vessels, an action which was strictly dependent on Ca2+. At the concentration of 500 microM, the effects of diltiazem were pronounced to the point of excluding completely about 2/3 of the liver parenchyma from the microcirculation, as indicated by the observed reduction in the accessible cell space. The sinusoids that were still supplied with perfusion fluid suffered considerable distension (2.19 fold) because the whole perfusate flow was deviated into the remaining 1/3 microcirculatory units. Diltiazem did not seem to induce the formation of intrahepatic shunts or diffusion barriers in the liver.

Animals↗