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PubMed1995

Prevention of tolerance to hemodynamic effects of nitrates with concomitant use of hydralazine in patients with chronic heart failure.

OBJECTIVES: This study was designed to determine the effect of oral hydralazine on the development of nitrate tolerance in patients with chronic congestive heart failure. BACKGROUND: Early development of nitrate tolerance with either continuous administration of intravenous or topical nitrate preparations or frequent dosing of oral nitrates leads to significant attenuation of nitrate-mediated hemodynamic and anti-ischemic effects. In recent animal experiments, prevention of nitroglycerin-induced hemodynamic tolerance with a concomitant use of hydralazine was demonstrated. This finding may have important clinical relevance. METHODS: Twenty-eight patients with chronic heart failure due to left ventricular systolic dysfunction were randomized to receive either a continuous infusion (24 h) of nitroglycerin alone (group I, 14 patients) or concomitantly with oral hydralazine (75 mg four times a day [group II, 14 patients]). The effect of nitroglycerin in each group was evaluated by analysis of variance for repeated measures. The power of the analysis to detect a 5.4-mm Hg (20%) change in mean pulmonary artery wedge pressure was 90%. RESULTS: Baseline hemodynamic variables as well as the initial hemodynamic response to nitroglycerin were comparable in both groups. Compared with the initial response to nitroglycerin, a significant attenuation of effect was found in group I at 24 h in mean (+/- SE) pulmonary artery pressure (27 +/- 4% vs. 10 +/- 3%, p < 0.05) and mean pulmonary artery wedge pressure (40 +/- 4% vs. 16 +/- 4%, p < 0.05). In group II, conversely, oral hydralazine prevented nitroglycerin-induced hemodynamic tolerance and resulted in a persistent effect on mean pulmonary artery and wedge pressures throughout the study period (31 +/- 3% vs. 27 +/- 4%, p = 0.13 and 37 +/- 4% vs. 34 +/- 6%, p = 0.40, respectively). In addition, the initial effect on blood pressure was attenuated at 24 h in group I (5 +/- 2% vs. 12 +/- 3%, p < 0.05) but not in group II (15 +/- 3% vs. 17 +/- 2%, p = 0.46). CONCLUSIONS: In patients with chronic heart failure due to left ventricular systolic dysfunction, the concomitant use of oral hydralazine prevents early development of nitrate tolerance and results in a persistent nitrate-mediated hemodynamic effect on systemic and pulmonary artery and left ventricular filling pressures. These data may support the concurrent use of hydralazine in patients with heart failure treated with organic nitrates.

Administration, Oral↗
PubMed1986

Hemodynamics of transcutaneous cardiac pacing.

Transcutaneous cardiac pacing has recently been rediscovered as a rapid means of initiating emergency cardiac pacing. Potential myocardial injury from extended transcutaneous pacing could adversely affect cardiac hemodynamics during pacing. This canine study compares the hemodynamics of transcutaneous and transvenous cardiac pacing in animals with induced chronic heart block. One to two weeks following chemical ablation of the His bundle, hemodynamic measurements were made during 60 minutes of transcutaneous and 5-minute periods of conventional right ventricular endocardial pacing. Cardiac index and output were found to increase significantly (P less than 0.005), and systemic vascular resistance was found to decrease significantly (P less than 0.005) from baseline values with both pacing techniques. A hemodynamic difference between pacing techniques was evident only for mean arterial blood pressure; pressure measurements during transvenous pacing were slightly greater than those during transcutaneous cardiac pacing. The hemodynamic measurements were found to be stable during a 60-minute period of transcutaneous cardiac pacing. This study demonstrates that transcutaneous cardiac pacing is as effective hemodynamically as conventional transvenous pacing in animals with induced chronic heart block.

Animals↗
PubMed1996

Hemodynamic effects of intrathecal fentanyl in nonlaboring term parturients.

STUDY OBJECTIVE: To determine the effect of intrathecal fentanyl on maternal hemodynamics. DESIGN: Prospective. SETTING: Labor and delivery suite of a university medical center. PATIENTS: 23 ASA status I nonlaboring term parturients presenting for elective cesarean section. INTERVENTIONS: Patients were given either 1,200 ml lactated Ringer's Solution (Group 1, n = 12) or no intravenous (i.v.) fluid (Group 2, n = 11). A combined spinal-epidural technique was then performed. Fentanyl 25 micrograms was administered intrathecally through a 24-gauge Sprotte or 25-gauge Whitacre spinal needle. After completion of the hemodynamic study, a catheter was threaded into the epidural space for local anesthetic administration. MEASUREMENTS AND MAIN RESULTS: Baseline hemodynamic data [systolic (SBP), diastolic, and mean arterial pressure, heart rate, stroke volume, cardiac output, end-diastolic volume, and ejection fraction] were obtained in triplicate using noninvasive blood pressure monitoring and impedance cardiography. After administration of intrathecal fentanyl, hemodynamic measurements were recorded at 3-minute intervals for 30 minutes. These values were compared with baseline for both groups. Ten patients in each group completed the study. Intrathecal fentanyl administration did not result in any maternal hemodynamic changes in Group 1, and a few small statistically significant changes in Group 2. Measured SBP was always greater than 100 mmHg in all patients during the study. CONCLUSION: Intrathecal administration of fentanyl 25 micrograms in nonlaboring term parturients does not produce clinically important maternal hemodynamic changes.

Adult↗
PubMed1993

Clonidine premedication for coronary artery bypass grafting under high-dose alfentanil anesthesia: intraoperative and postoperative hemodynamic study.

The purpose of this study was to assess the efficacy of clonidine in achieving perioperative hemodynamic stability in patients undergoing coronary artery bypass grafting performed under high-dose alfentanil anesthesia. Twenty-four patients with left ventricular ejection fraction greater than 0.5 were prospectively studied in a double-blind manner; those requiring emergency procedures were excluded. They were randomized to receive either oral clonidine or placebo together with their premedication. Induction of anesthesia was achieved with 10 mg of alfentanil infused over 5 minutes followed by a continuous infusion of 60 mg/h during 1 hour, or until sternotomy, and then 30 mg/h until the end of surgery. Hemodynamic responses to noxious stimuli were treated with additional alfentanil boluses and isoflurane when these were unsuccessful. Intraoperative hemodynamic profile analyses showed a continuous increase in systemic vascular resistance and mean arterial pressure in the clonidine group from the time of skin incision until the onset of bypass, whereas the cardiac output profiles remained similar in the two groups. The number of additional alfentanil boluses was similar. Isoflurane requirements (1/11 v 4/13) were not significantly different, but only a few patients required this therapy. The postbypass hemodynamic profiles were similar. Severe hemodynamic impairment occurred in the clonidine group during warming in the postoperative period: this group showed a drop in systemic vascular resistance index (1276 +/- 347 v 1757 +/- 415 dyn.sec.cm-5.m2) that could not be compensated for by an increase in cardiac output despite normal filling pressures, causing hypotension (66 +/- 10 v 79 +/- 16 mmHg). This hemodynamic status led to greater requirements for vasoactive agents and inotropics in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Alfentanil↗
PubMed2005

Prognostic value of hemodynamic findings from impedance cardiography in hypertensive stroke.

BACKGROUND: Impedance cardiography (ICG), a noninvasive method of hemodynamic monitoring, is a useful tool in the care of critically ill patients. Use of this technology shows promise in the hemodynamic assessment of hypertensive stroke patients. This study describes the different ICG findings of patients with hypertensive stroke and correlates parameters with patient outcome. METHODS: Adult patients with stroke admitted to the intensive care unit (ICU) who were on antihypertensive medications or had hypertensive blood pressure (BP) levels at the time of admission were included. Patients were classified as having ischemic or hemorrhagic stroke on the basis of imaging studies. The ICG was done in the initial 24 h of admission using the BioZ Cardiac Output Monitor (CardioDynamics, Inc., San Diego, CA) and 18 hemodynamic parameters were analyzed. Statistical analysis was performed to assess correlation of hemodynamic findings with the type of stroke and survival to hospital discharge. RESULTS: Fifty-two adult patients with a mean age of 60.5 +/- 12.4 years were included. Of this population, 29 had ischemic stroke and 23 had hemorrhagic stroke. Seventeen patients died during hospital stay. Overall, noninvasive hemodynamic parameters of stroke patients showed a high systemic vascular resistance index (SVRI) and systemic vascular resistance (SVR), and decreased cardiac output (CO), stroke index (SI), and stroke volume (SV). Among the ischemic stroke group, nonsurvivors had a significantly higher mean SVRI and mean SVR compared to the survivors. In contrast, among the hemorrhagic stroke patients, nonsurvivors had a significantly lower mean SVRI and SVR compared to survivors. Except for SI and BP, there was no difference in the noninvasive hemodynamic parameters between the ischemic stroke group and the hemorrhagic stroke group. CONCLUSIONS: In this population of hypertensive stroke patients admitted to the ICU, ICG showed an elevated SVRI and SVR and depressed CO, SV, and SI. In the ischemic stroke group, higher SVR and SVRI were associated with in-hospital death, whereas in the hemorrhagic stroke group, lower SVR and SVRI were associated with in-hospital death. The ICG may provide significant prognostic information in patients admitted with hypertensive stroke.

Aged↗
PubMed2005

Acute hemodynamic effects of pacing in patients with Fontan physiology: a prospective study.

OBJECTIVES: The purpose of this research was to assess the hemodynamic response to atrial, ventricular, and dual-chamber pacing in patients with Fontan physiology. BACKGROUND: Bradycardia, due to sinus node dysfunction or atrioventricular (AV) block, with need for pacing, is common after the Fontan operation. The optimal pacing mode for Fontan patients is unknown, but is critical, as hemodynamic aberrancies may cause severe clinical deterioration. We hypothesized that AV synchrony is vital for maximizing Fontan hemodynamics. METHODS: A cross-over trial was conducted with 21 patients (age 2 to 18 years, median 4 years; male patients = 13) in the intensive care unit after a Fontan operation. Hemodynamic parameters, including mean left atrial pressure (LAP, in mm Hg), mean pulmonary artery pressure (PAP, in mm Hg), mean arterial blood pressure (MAP, in mm Hg), and indexed cardiac output via Fick (Qs, in l/min/m2) were measured with atrial, ventricular, and dual-chamber pacing. Measurements were made after pacing for 10 min in each mode, and a 10-min rest was given between each pacing maneuver. RESULTS: Asynchronous ventricular (VOO) pacing resulted in significantly worse hemodynamics when compared to dual-chamber (DOO) and atrial (AOO) pacing with a higher LAP (9.4 VOO; 6.8 DOO; 5.4 AOO) and PAP (15.2 VOO; 13.5 DOO; 12.7 AOO) and lower Qs (3.0 VOO; 3.5 DOO; 3.9 AOO) and MAP (60.1 VOO; 66.5 DOO; 67.2 AOO). CONCLUSIONS: Asynchronous ventricular pacing, after the Fontan procedure, has acute, adverse hemodynamic consequences (elevated LAP and PAP and decreased Qs and MAP).

Adolescent↗
PubMed2005

Adrenergic drugs alter both the fluid kinetics and the hemodynamic responses to volume expansion in sheep.

BACKGROUND: Plasma volume expansion is often performed during adrenergic therapy in the intensive care unit, but little is known about their combined effects. MATERIALS AND METHODS: The influence of three adrenergic drugs (50 microg/kg/min of dopamine, 0.1 microg/kg/min of isoprenaline, or 3 microg/kg/min of phenylephrine) on the relationship between plasma dilution (an index of volume expansion) and the central hemodynamic responses to volume loading with 24 ml/kg of 0.9% saline were evaluated in 6 adult sheep. Kinetic analysis was also applied to the data on plasma dilution and the urinary excretion measured during and after volume loading. RESULTS: The adrenergic agents markedly changed the baseline values for all hemodynamic parameters. The kinetic analysis showed that phenylephrine, which is an alpha-adrenergic receptor agonist, promoted renal excretion of infused fluid at the expense of fluid distribution to the periphery (P < 0.05 versus controls). Isoprenaline, which stimulates adrenergic beta-receptors, had the opposite effect. During volume expansion, cardiac atrial pressures increased by 25 to 90%, cardiac output by 13-80% and the arterial pressures by 2 to 22%. Plasma dilution during and after volume loading correlated, in a linear fashion, with these hemodynamic responses. The correlations were strong (r > 0.80) in the control and phenylephrine groups, but weaker in the dopamine and isoprenaline groups. Dopamine was associated with the most variable hemodynamic responses overall. CONCLUSIONS: Adrenergic drugs altered the hemodynamics at baseline (direct effects), changed the distribution and elimination of infused 0.9% saline (indirect effects) and, finally, modified most hemodynamic responses to plasma dilution (interaction effects).

Adrenergic alpha-Agonists↗
PubMed2004

Hemodynamic and clinical impact of ultrasound-derived venous reflux parameters.

PURPOSE: This study was undertaken to assess which ultrasound-derived parameter was superior for measuring venous reflux quantitatively and to evaluate the importance of popliteal vein valve reflux. PATIENTS AND METHODS: A retrospective analysis was performed of 244 refluxive limbs in 182 patients who underwent ultrasound scanning, venous pressure measurement, air plethysmography, and clinical classification of severity according to the CEAP score. Reflux time (RT, s), peak reflux velocity (PRV, m/s), time of average rate of reflux (TAF, mL/min), absolute displaced volume retrogradely (ADV, mL) were compared to clinical class, ambulatory venous pressure (% drop), venous filling time (s), and venous filling index (mL/s) using nonparametric statistical tests. A P value of <.05 was considered significant. Limbs were divided into 3 groups: (A) axial great saphenous vein reflux only (n = 68); (B) axial deep reflux including popliteal vein incompetence with or without concomitant gastrocnemius or great or small saphenous vein reflux (all ultrasound reflux parameters of each refluxive vein added at the knee level) (n = 79); and (C) all limbs with popliteal vein reflux (the ultrasound data of the refluxive popliteal vein exclusively was used in comparison regardless of concomitant associated reflux) (n = 103). Limbs were also stratified into limbs with skin changes and ulcer (C-class 4-6) and those without (C-class 1-3) and subsequently compared. RESULTS: No meaningful significant correlation was found between RT and the clinical and hemodynamic results in groups A and B. The PRV and TAF correlated significantly with the hemodynamic parameters. The PRV and TAF and clinical severity trended towards correlation in group A (P =.0554 and P =.0998, respectively), but was significantly correlated in group B. The poor hemodynamic condition in the subset of C-class 4-6 limbs in groups A and B was reflected in a greater PRV, TAF, and ADV in this subset as compared with the limbs in C-class 1-3. RT was not significantly different in the subsets of limbs, further suggesting that RT is not related to hemodynamic or clinical state of the limbs. No meaningful correlations were found in group C. Although the hemodynamic data were significantly poorer in the subset of limbs with C-class 4-6 than in C-class 1-3, the ultrasound-derived parameters were not significantly different. CONCLUSION: The duration of valve reflux time (or valve closure time) cannot be used to quantify severity of reflux and is purely a qualitative measurement. The PRV and the rate of reflux appeared to better reflect the magnitude of venous incompetence. In the presence of axial reflux, it appeared logical and physiologically correct to sum up these reflux parameters for each venous segment crossing the knee. The popliteal valve reflux (the "gatekeeper" function) was not in itself an important determinant of venous hemodynamics and clinical severity. Additional reflux in other venous segments must be taken into account.

Adolescent↗
PubMed1996

Mitral flow velocity changes after 6 months of optimized therapy provide important hemodynamic and prognostic information in patients with chronic heart failure.

Transmitral flow velocity patterns evaluated by Doppler echocardiography provide important hemodynamic and prognostic information in various cardiac conditions. However, these patterns may change over time, and so far the hemodynamic and prognostic significance of these changes has not been established. Accordingly, we performed this study to determine the hemodynamic and prognostic value of changes in transmitral flow velocity patterns after 6 months of optimized medical treatment in patients with chronic heart failure due to ischemic or nonischemic dilated cardiomyopathy. Ninety-eight consecutive patients with chronic heart failure underwent a clinical examination, a cardiopulmonary exercise test, and simultaneous Doppler echocardiographic and hemodynamic studies at baseline and after 6 months, patients were followed up for 12 +/- 7 months. Cardiac death and heart transplantation while patients were in critical condition were considered events. A restrictive pattern was defined by an early-to-late peak diastolic velocity ratio > 1 and an early diastolic deceleration time < or = 130 msec. Patients were grouped according to their mitral flow pattern at baseline and its changes after chronic optimized therapy. No significant changes in clinical, ergometric, and hemodynamic variables were found after 6 months in the 49 patients who had a persistent restrictive transmitral flow pattern or the 24 patients who had a persistent nonrestrictive transmitral flow pattern. In the 19 patients who had a restrictive pattern at baseline that reverted into a nonrestrictive pattern, this change was accompanied by a highly significant reduction in pulmonary wedge pressure (from 25 +/- 7 mm Hg to 11 +/- 3 mm Hg) and by an increase in exercise capacity, whereas in the 6 patients who had a nonrestrictive pattern that became restrictive, hemodynamic features markedly deteriorated. Seventeen of the 21 events occurred in the 49 patients (event rate 35%) with a persistent restrictive pattern, whereas the event rate was much lower in the 19 patients with a reversible restrictive pattern (5%) and in the 24 patients with a persistent nonrestrictive pattern (4%). Two (33%) of the 6 patients in whom a restrictive pattern developed had events. Cox analysis revealed that a restrictive transmitral flow pattern (p = 0.0068) and peak rate of oxygen consumption (p = 0.0056) detected at the late examination were significantly related to cardiac events. These results show that in patients with chronic heart failure, changes in transmitral flow patterns after chronic optimized therapy are correlated with changes in pulmonary wedge pressure, are accompanied by changes in functional capacity, and provide relevant independent prognostic information.

Blood Flow Velocity↗
PubMed1998

Effective arterial elastance and the hemodynamic effects of intraaortic balloon counterpulsation in patients with coronary heart disease.

OBJECTIVES: The goal of the present study was to analyze the effects of different intraaortic balloon counterpulsation (IABC) inflation volumes on effective arterial elastance (Ea) in patients with complicated coronary heart disease and to determine whether Ea can predict the hemodynamic response to IABC. BACKGROUND: Ea (the central aortic end-systolic pressure to stroke volume ratio) incorporates the principal elements of input arterial impedance and has been proved useful to evaluate the effects of afterload reduction in patients with left ventricular (LV) failure. However, although the hemodynamic action of IABC can be considered as a typical example of "pure" afterload reduction, it has never been assessed in terms of changes in Ea. METHODS: After clinical stabilization, 18 patients treated with IABC for complicated acute myocardial infarction or unstable angina were enrolled in the study. Systemic hemodynamics were measured by use of right cardiac thermodilution catheters with IABC off (control) and IABC on at balloon inflation volumes of 20 and 40 ml, in randomized sequence. Aortic pressure was recorded through the central lumen of the IABC catheter to calculate Ea as the ratio of aortic dicrotic pressure to stroke volume. RESULTS: A higher control Ea was associated with a lower control LV stroke work and a larger IABC-related hemodynamic improvement (that was maximal with the 40 ml inflation volume). The increase in LV stroke work was closely related to the decrease in Ea. Accordingly, hemodynamic benefits from IABC were less evident in patients with lower control Ea. In conclusion, effects of IABC were related to both balloon inflation volume and control hemodynamics, reflecting the afterload dependence of a depressed LV function.

Aged↗
PubMed1999

Intermittent milrinone effect on long-term hemodynamic profile in patients with severe congestive heart failure.

BACKGROUND: Many reports have suggested that intermittent milrinone infusion (IMI) may be efficacious in the management of end-stage congestive heart failure (CHF), but this issue has not been clearly established. The aim of our study was to investigate the effectiveness of IMI in hospitalized patients with severe CHF undergoing long-term (4 months) post-therapy hemodynamics. METHODS: Thirty-six patients (28 men, 8 women; mean age 65.6 +/- 8.2 years old) with end-stage CHF (New York Heart Association functional class III-IV) were studied. Each patient received 4 cycles of 3 days per week with milrinone therapy. Each cycle consisted of a loading dose of 50 microgram/kg over 10 minutes and a 72-hour continuous infusion of 0.5 microgram/kg per minute under close monitoring. Hemodynamic changes were determined during the first and fourth cycles and on 4-month reexamination. Full clinical examination was performed at the beginning (baseline) and at the end of 4-month follow-up. RESULTS: The values of mean pulmonary arterial pressure, pulmonary capillary wedge pressure, systemic vascular resistance, and pulmonary vascular resistance were significantly decreased (P <.01) and cardiac index was significantly increased (P <.01) compared with the baseline of first and fourth cycles. At the end of the 4-month follow-up period all hemodynamic parameters sustained the improvement. Clinical examination at the end of the 4-month period showed that 21 (58.3%) of 36 patients remained in New York Heart Association functional class IV but were hemodynamically improved, 13 (36.2%) of 36 were in functional class III, and 2 (5.5%) of 36 were in class II-III. There were no deaths during the study period. CONCLUSIONS: Our findings suggest that IMI in hospitalized patients with severe CHF is hemodynamically efficacious. This beneficial hemodynamic effect is maintained for at least 4 months after discontinuation of therapy. These promising results raised the possibility that given appropriately, milrinone may have an important role in end-stage CHF.

Cardiotonic Agents↗
PubMed2000

Hemodynamic changes and right heart support during vertical displacement of the beating heart.

BACKGROUND: Hemodynamic instability during heart displacement in off-pump multivessel coronary artery bypass grafting might be related to right heart dysfunction. The Enabler (HemoDynamics Systems Ltd, Upper Yoqneam, Israel) is a cannula pump that expels blood from the right atrium into the pulmonary artery. We studied the hemodynamic changes and the role of the enabler during heart displacement. METHODS: Nine anesthetized sheep were assessed for hemodynamic changes during 90-degree heart displacement with or without Enabler support. Hemodynamic parameters included cardiac output, systemic arterial blood pressures, and left and right heart filling pressures. RESULTS: Heart displacement caused a significant decrease in cardiac output and systemic blood pressure (46%+/-5%, p = 0.001; and 20%+/-5%, p = 0.009, respectively), with a concomitant 137%+/-24% (p = 0.003) increase in central venous pressure. No significant change in left atrial pressure was observed. Activation of the Enabler caused a significant increase in cardiac output and systemic blood pressure (67%+/-15%, p = 0.01; and 17%+/-7%, p = 0.04, respectively), as well as a decrease in central venous pressure by 49%+/-8% (p = 0.0001). CONCLUSIONS: Heart displacement causes hemodynamic instability mainly by right heart dysfunction. The Enabler significantly stabilized circulation during vertical displacement of the beating heart.

Animals↗
PubMed1998

Echocardiographic hemodynamic and morphometric predictors of survival after two-ventricle repair in infants with critical aortic stenosis.

OBJECTIVES: The purpose of this study was to identify echocardiographic hemodynamic and morphometric factors that would predict which infants with critical aortic stenosis could undergo relief of left ventricular outflow obstruction as opposed to the Norwood procedure. BACKGROUND: Echocardiographic predictors of survival in infants with critical aortic stenosis after two-ventricle repair have been mainly limited to morphometric factors, which have limitations. Echocardiographic hemodynamic predictors of survival in these patients have not previously been studied. METHODS: Doppler color flow mapping and pulsed Doppler techniques were used to obtain hemodynamic measurements of flow in the ascending, transverse and descending aorta, the ductus arteriosus, and across the aortic and mitral valves in infants with critical aortic stenosis. Morphometric measurements of the left heart structures were obtained, and comparisons were made between survivors and nonsurvivors for the hemodynamic and morphometric factors. RESULTS: Twenty-eight infants (mean age 1 +/- .6 days, mean weight 3.6 +/- .6 kg) with critical aortic stenosis were evaluated. Nineteen had a two-ventricle repair initially attempted, and nine had a Norwood operation. Among the patients with a two-ventricle repair, the hemodynamic factors associated with survival after two-ventricle repair included predominant or total antegrade flow in the ascending (p < 0.01) and transverse aorta (p < 0.05). Aortic valve gradient, mitral valve inflow and direction of flow in the ductus arteriosus and descending aorta were unrelated to outcome. The morphometric factors associated with survival after two-ventricle repair included the indexed aortic annulus (p < 0.0002), aortic root (p < 0.003), ascending aorta (p < 0.008) and left ventricular long-axis length (p < 0.01). Left ventricular volume, mass, ejection fraction and mitral valve area were not related to outcome after two-ventricle repair. CONCLUSIONS: In infants with critical aortic stenosis, predominant or total antegrade flow in the ascending and transverse aorta was associated with survival after two-ventricle repair. Determination of a one- versus two-ventricle repair remains a complex issue in infants with critical aortic stenosis. In addition to established morphometric predictors, hemodynamic information on the direction of flow in the aorta may help to define candidates for the Norwood operation.

Aortic Valve Stenosis↗
PubMed2000

Hemodynamic comparison of twice daily metoprolol tartrate with once daily metoprolol succinate in congestive heart failure.

OBJECTIVES: To compare the hemodynamic effects of twice daily metoprolol tartrate (MT) and once daily metoprolol succinate (MS) in congestive heart failure patients. BACKGROUND: Adverse hemodynamic effects with MT demonstrated during initiation persist with drug readministration during chronic therapy. METHODS: Patients were randomly assigned to 6.25 mg MT or 25 mg MS orally and the dose was gradually increased to a target of 50 mg twice a day or 100 mg once a day, respectively. Hemodynamic measurements were obtained at baseline and after three months of therapy--both before and after drug readministration. RESULTS: Long term metoprolol therapy produced significant functional, exercise and hemodynamic benefits with no difference in response between either metoprolol preparation in the 27 patients (MT [14], MS [13]). When full dose metoprolol was readministered during chronic therapy, there were parallel adverse hemodynamic effects in both drug groups. Cardiac index decreased by 0.6 liters/min/m2 (p < 0.0001) with MT and by 0.5 liters/min/m2 (p < 0.0001) with MS. Systematic vascular resistance increased by 253 dyne-sec-cm(-5) (p < 0.001) with MT and by 267 dyne-sec-cm(-5) (p < 0.0005) with MS. Stroke volume index decreased by 7.0 ml/m2 (p < 0.0005) with MT and by 6.5 ml/m2 (p < 0.0001) with MS, while SWI decreased by 6.2 g-m/m2 (p < 0.0005) with MT and by 6.0 g-m/m2 (p < 0.001) with MS. CONCLUSION: Metoprolol tartrate and MS produce similar hemodynamic and clinical effects acutely and chronically despite the fourfold greater starting dose of MS used in this study. A more rapid initiation with readily available starting doses of MS may offer distinct advantages compared with MT in treating chronic heart failure patients with beta-adrenergic blocking agents.

Administration, Oral↗
PubMed2000

The effects of transesophageal echocardiography on hemodynamic variables in small infants undergoing cardiac surgery.

OBJECTIVE: To assess the effects of transesophageal echocardiography (TEE) on hemodynamic variables during cardiac surgery in small infants. DESIGN: A prospective clinical study. SETTING: A medical college-affiliated tertiary care children's hospital. PARTICIPANTS: Twenty-three infants weighing 2 to 5 kg undergoing cardiac surgery. INTERVENTIONS: Baseline heart rate, arterial pressure, and central venous pressure were recorded. A pediatric TEE probe was inserted, and the hemodynamic variables were again recorded. Postoperatively the hemodynamic measurements were measured again before and after probe removal, with the addition of left atrial pressure and pulmonary artery pressure when available. Hemodynamic parameters were carefully observed during all phases of the TEE examinations for any changes attributable to probe manipulation. MEASUREMENTS AND MAIN RESULTS: No statistically significant changes occurred in this group of patients during TEE. No clinically significant changes in any individual patient occurred during the measurement or during manipulation of the TEE probe for the complete examination. CONCLUSION: Although hemodynamic compromise can occur in small infants, this study suggests that it is infrequent. Fear of hemodynamic compromise should not prevent use of intraoperative TEE in small infants when otherwise indicated.

Cardiac Surgical Procedures↗
PubMed2001

Death after rejection with severe hemodynamic compromise in pediatric heart transplant recipients: a multi-institutional study.

BACKGROUND: Rejection with severe hemodynamic compromise results in high mortality in adult transplant patients. This study determines the incidence, outcome and risk factors for rejection with severe hemodynamic compromise in a multi-institutional study of pediatric heart transplant recipients. METHODS: Data from 847 patients transplanted between 1/1/93 and 12/31/98 at 18 centers in the Pediatric Heart Transplant Study were analyzed. Rejection with severe hemodynamic compromise was defined as a clinical event occurring beyond 1 week postoperatively, which led to augmentation of immunosuppression and use of inotropic therapy. Actuarial freedom from such rejection and death after rejection were determined and risk factors sought. RESULTS: Among 1,033 rejection episodes in 532 patients, 113 (11%) episodes were associated with severe hemodynamic compromise in 95 patients. The highest risk for severe rejection was in the first year. Risk factors were older recipient age (p >.05) and non-white race (p >.001). Survival after an episode was poor (60%), and biopsy score did not affect outcome. Deaths were due to rejection (n = 14), other cardiac causes (n = 17), infection (n = 5), lymphoma (n = 2), pulmonary causes (n = 2), and thrombosis (n = 1). CONCLUSIONS: Rejection with severe hemodynamic compromise occurs in 11% of pediatric patients, irrespective of age, sex or biopsy score, and mortality is high. Non-white race and older recipient age are independent risk factors for rejection with severe hemodynamic compromise. Aggressive treatment and close surveillance should be crucial components of protocols aimed at reducing the high mortality.

Adolescent↗
PubMed1999

Interventions to improve cardiopulmonary hemodynamics during laparoscopy in a porcine sepsis model.

BACKGROUND: Laparoscopy is increasingly used in severely ill and acutely septic patients. In animals undergoing laparoscopy, the hemodynamic response to sepsis is blunted. Specific interventions to augment the hemodynamic potential may make laparoscopic intervention a safer alternative in septic patients. We compared different interventions to improve hemodynamic performance during exploratory laparoscopy in a porcine endotoxic shock model. STUDY DESIGN: Domestic pigs (n = 12) received intravenous lipopolysaccharide injection and underwent surgical abdominal exploration using either laparoscopy or conventional laparotomy. For comparison, pigs exposed to endotoxin underwent laparoscopy with these interventions: intravenous infusions of prostacyclin (n = 5) or indomethacin (n = 4), intravenous crystalloid resuscitation (n = 5), pulmonary hyperventilation (n = 4), or abdominal insufflation with air (n = 5). Hemodynamic measurements and blood gas analyses were obtained using Swan-Ganz and arterial catheters. RESULTS: Septic animals treated with prostacyclin undergoing laparoscopy had a higher cardiac index (CI, p < 0.01), stroke volume (SV; p < 0.001) and oxygen delivery (p < 0.05) than the untreated group. Likewise, treatment with indomethacin was associated with a higher CI (p < 0.001), SV (p < 0.005), and oxygen delivery (p < 0.005) compared with the untreated group. These effects may be secondary to a decreased pulmonary vascular resistance, demonstrated in the animals that received either prostacyclin (p < 0.05) or indomethacin (p < 0.05). In addition, animals given aggressive fluid resuscitation had a significantly higher CI (p < 0.05) and SV (p < 0.001) than those with normal fluid resuscitation during laparoscopy. Manipulation of arterial pH by insufflation of the abdomen with air to create the pneumoperitoneum, or by aggressively hyperventilating the animals, did not improve CI. CONCLUSIONS: Adverse effects of laparoscopy on cardiovascular hemodynamics in the septic state may be mediated by increased pulmonary vascular resistance, diminished venous return, or both. Specific interventions to reverse these variables may ameliorate hemodynamic changes seen.

Analysis of Variance↗
PubMed2001

Laparoscopic surgery for extrauterine pregnancy in hemodynamically unstable patients.

STUDY OBJECTIVE: To assess the feasibility and safety of laparoscopic surgery in treatment of ectopic pregnancy in hemodynamically unstable women. DESIGN: Three-year observational study (Canadian Task Force classification II-2). SETTING: Tertiary university hospital. PATIENTS: One hundred one women with ectopic pregnancy who underwent laparoscopic surgery, 18 with substantial intraabdominal bleeding and with clinical signs and symptoms of hemodynamic instability. INTERVENTION: Laparoscopic surgery. MEASUREMENTS AND MAIN RESULTS: Compared with stable patients, hemodynamically unstable women had significantly more free blood in the abdomen (1244 +/- 590 vs 173 +/- 301 ml, p <0.0001), had significantly lower hemoglobin levels (7.8 +/- 1.4 vs 11.9 +/-1.4 g%, p <0.0001), and required significantly more frequent blood transfusions (83% vs 3.6%, p <0.0001). Similarly, their hemodynamic values such as pulse rate and blood pressures were worse. Among these women, 15 (83%) had a tubal pregnancy, 2 had an interstitial pregnancy, and 1 had a tubal abortion. Those with tubal pregnancy who were hemodynamically unstable underwent salpingectomy. Only one required conversion to laparotomy. No major intraoperative or postoperative complications occurred, and all women made a full and uneventful recovery. CONCLUSION: Improved anesthesia and cardiovascular monitoring, together with advanced laparoscopic surgical skills and experience, justifies operative laparoscopy for surgical treatment of ectopic pregnancy even in women with hemodynamic instability.

Adult↗