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At least 19 recordsLinked to original sources
PubMed1977

Superiority of dobutamine over dopamine for augmentation of cardiac output in patients with chronic low output cardiac failure.

Dobutamine is a newly developed catecholamine reported to have minimal direct vascular effects relative to its inotropic activity and to have less chronotropic and arrhythmogenic properties than other catecholamines used in the treatment of low output states. In this study, the acute hemodynamic effects of dobutamine were compared to those of dopamine in 13 patients with chronic low output cardiac failure. At dosages adjusted to achieve similar increments in cardiac output, dobutamine reduced left ventricular filling pressure (LVEP) from 24 +/- 2 mm Hg (SEM) to 17+/- 2 mm Hg, while dopamine increased LVEP to 30 +/- 3 mm Hg and in six patients caused arterial O2 saturation to fall below 90%. This poor response to dopamine was probably the result of its vasoconstrictive effects and illustrates the potential advantages of using a cardioselective agent such as dobutamine when the desired goal of therapy is to improve ventricular function by direct inotropic stimulation.

Aged↗
PubMed1990

Clinical assessment of cardiac output.

Cardiac output estimation is an important and much needed measurement for assessing patients in heart failure. In hypertension, it is vital for understanding the haemodynamic basis of the disease and the mode of action of drugs. Measurements of blood pressure and cardiac output provide the only means of estimating peripheral resistance. Of the available methods to determine cardiac output, thermodilution is the most practical, although it has its difficulties and care has to be exercised in its use. When intra-arterial blood pressure measurements are needed, the dye-dilution method is equally valid, and if respiratory techniques are available the Fick principle may also be used. Of the non-invasive methods, none is yet developed to a stage suitable for general clinical use. Doppler velocimetry is the most promising technique, but it requires complex computer analysis and, as yet, can reliably be used only to measure changes in cardiac output in an individual. The technique has been assessed against the electromagnetic flowmeter in man and gives reasonable accuracy and repeatability. Echocardiography and impedance cardiography are not yet satisfactory for clinical use; neither are the radionuclide methods, apart from the 'first pass' method, but this also needs further verification.

Cardiac Output↗
PubMed1979

Evaluation of the microsphere-method for determination of cardiac output.

Cardiac output was determined by means of radioactive microspheres, 15 +/- 5 microns in diameter. Blood flow in the ascending aorta was measured by an electromagnetic flowmeter. In eight cats thirty-eight simultaneous measurements were made of cardiac output and aortic flow. The observations correlated well (r = 0.89), with a mean difference of 5.2%, probably corresponding to coronary blood flow. Continuous flow recordings showed no alterations in aortic flow during the injections of microspheres; arterial blood pressure and heart rate remained unchanged even after six injections, each consisting of about 2 x 10(5) spheres per kg body weight. Tests for shunting of microspheres were performed and revealed shunt fractions in the systemic circulation of about 8%, with no significant shunting through the lungs. The microsphere method for determining cardiac output is thought to be an accurate method, suitable for small and medium sized animals.

Animals↗
PubMed1991

Effects of variable dose milrinone in patients with low cardiac output after cardiac surgery. European Multicenter Trial Group.

We studied 99 adult patients after elective cardiac surgery who had low cardiac output (cardiac index less than 2.5 L/min/m2) in spite of adequate cardiac filling pressure (pulmonary capillary wedge pressure less than 8 mm Hg). Patients received milrinone by loading dose (50 micrograms/kg over a 10-minute period), followed by a continuous infusion of either 0.375, 0.5, or 0.75 micrograms/kg/min (low-, middle-, and high-dose groups, respectively) given for a minimum of 12 hours. Patients were allocated to each dosage group sequentially, not randomly. Hemodynamic measurements were made before the loading dose and at 15, 30, 45, and 60 minutes, 3, 6, and 12 hours after the start of milrinone therapy. Further measurements were made at 2 and 4 hours after treatment was stopped. Milrinone therapy was associated with a rapid, well-sustained, and highly significant increase in cardiac index in all three dose groups (p less than 0.001), and a similar fall occurred in pulmonary capillary wedge pressure in all groups (p less than 0.001). Significant increases occurred in heart rate in all three groups (p less than 0.001). Systemic and pulmonary vascular resistance also fell significantly, although changes in this latter parameter were less predictable and more dose dependent. Few serious treatment-related adverse effects were seen. We conclude that intravenous milrinone is an effective and safe therapy for the treatment of low output states after cardiac surgery.

Cardiac Output↗
PubMed1991

Clinical and haemodynamic effects of milrinone in the treatment of low cardiac output after cardiac surgery.

We have studied the haemodynamic effects of i.v. milrinone, a new phosphodiesterase inhibitor, in patients with low cardiac output after cardiac surgery. Thirty-five patients with a cardiac index (Cl) less than 2.5 litre min-1 m-2 and a pulmonary capillary wedge pressure (PCWP) greater than 8 mm Hg were given a loading dose of milrinone 50 micrograms kg-1 followed by an infusion at one of three rates: 0.375 micrograms kg-1 min-1, 0.5 micrograms kg-1 min-1 or 0.75 micrograms kg-1 min-1 for 12 h. After 1 h there were increases in Cl (35%) (P less than 0.001), heart rate (13%) (P less than 0.01) and stroke volume index (19%) (P less than 0.005). There were decreases in mean arterial pressure (12%) (P less than 0.01), systemic vascular resistance (35%) (P less than 0.001) and PCWP (24%) (P less than 0.05). Pulmonary vascular resistance was unchanged or reduced and left ventricular stroke work index was unchanged or increased. The haemodynamic improvements were sustained throughout the infusion period. Milrinone was tolerated well: three patients developed tachycardia greater than 125 beat min-1, one patient developed atrial fibrillation and one patient had a short run of atrial bigemini. We conclude that milrinone is a useful agent in the treatment of patients with a reduced cardiac output after cardiac surgery.

Adult↗
PubMed1992

Prolonged infusion of varied doses of dopexamine hydrochloride for low cardiac output after cardiac surgery.

Circulatory failure after cardiac surgery often calls for active hemodynamic management with fluids, inotropes, and vasodilators. Dopexamine hydrochloride is a new combined beta 2-adrenergic and DA1-dopaminergic receptor agonist and an inhibitor of the uptake-1 mechanism of endogenous catecholamines. As a result, it exerts inotropic and vasodilator effects on the heart and systemic vasculature. The effects were examined over a mean of 22 hours, using 1 to 4 micrograms/kg/min of dopexamine to treat low cardiac output states following coronary bypass and valvular/ventricular repair surgery. In 8 out of 14 patients, low cardiac output was readily reversed by 1 microgram/kg/min of dopexamine. Six patients required higher doses (2 to 4 micrograms/kg/min) to achieve a satisfactory cardiac index. Significant changes from control values were observed throughout the infusion for heart rate (67 to 102 beats/min), cardiac index (2.0 to 3.4 L/min/m2), and systemic vascular resistance (1,545 to 914 dyne.s.cm-5). Pulmonary vascular resistance, pulmonary artery wedge pressure, and right atrial pressure were also significantly reduced during the infusion. Most of these changes reversed when dopexamine was discontinued, suggesting a drug-specific effect and a lack of tolerance. Nausea was a frequent complaint, but was no more frequent than in a random sample of similar patients. Titration of dopexamine, 1 to 4 micrograms/kg/min, was efficacious in producing circulatory improvement in patients with a low cardiac output after cardiac surgery.

Adrenergic Agonists↗
PubMed1991

Continuous extracorporeal fluid removal in children with low cardiac output after cardiac operations.

Eleven hypervolemic and oliguric children with low cardiac output after cardiac operations were treated by slow continuous ultrafiltration or continuous arteriovenous hemofiltration. A mean negative fluid balance of 1.63 +/- 0.37 ml/kg/hr (standard error of the mean [SEM]) significantly improved the hemodynamic status within 59 +/- 6.1 hours (SEM). Although the central venous pressure decreased significantly from 15.2 +/- 0.84 to 8.8 +/- 0.92 mm Hg (p less than 0.0001), the mean arterial pressure increased significantly from 41.5 +/- 2.54 to 53.5 +/- 2.21 mm Hg (p less than 0.001). In addition, pH increased significantly from 7.31 +/- 0.01 (SEM) to 7.43 +/- 0.001 (SEM) (p less than 0.001) and oxygenation index (arterial oxygen tension/inspired oxygen fraction) from 119 +/- 15.2 (SEM) to 214 +/- 27.0 (SEM) (p less than 0.001). Hemodynamic improvement during slow continuous extracorporeal fluid removal allowed a significant decrease of the catecholamine infusion rate. After normovolemia had been achieved, continuous arteriovenous hemofiltration had to be continued in four children because of persistent anuria. Eight patients could be weaned from artificial ventilation and vasopressor support. Two patients died without recovery of renal function and one with restored renal function. Slow continuous ultrafiltration and continuous arteriovenous hemofiltration improve the cardiovascular function in children with low cardiac output by optimizing the preload conditions of the failing heart. In addition, they improve acid-base balance and pulmonary gas exchange.

Blood Pressure↗
PubMed1990

[Comparison of enoximone versus tobutamine in the treatment of low cardiac output after cardiac surgery].

Enoximone, a new cardiotonic agent not related to glycosides or catecholamines, has been suggested for treatment of low cardiac output syndromes occurring after cardiopulmonary bypass (CPB). The aim of the present study was to compare enoximone with dobutamine in the management of such cases. Twenty consecutive patients who had undergone cardiac surgery with CPB and who had a cardiac index (CI) less than 2.5 l.min-1.m-2, pulmonary capillary wedge pressure greater than 12 mmHg, and no renal failure, were randomly assigned to receive either enoximone (group E, n = 10) or dobutamine (group D, n = 10). The following parameters were monitored at baseline, 15, 30, 60, 90 min, 2, 6, 10 and 14 h: arterial, central venous, pulmonary arterial and capillary wedge pressures (PCWP), cardiac index (CI), stroke volume index (SVI), stroke work index (SWI), systemic (SVR) and pulmonary vascular resistances, as well as heart rate-pressure product (HRPP). Patients in group E were given a bolus of 0.5-1 mg.kg-1 enoximone over a 20 min period, followed by a continuous infusion of 2-20 micrograms.kg-1.min-1, depending on clinical response. In group D, patients were given 2.5 to 15 micrograms.kg-1.min-1 dobutamine according to clinical response. No other inotropic drug was used during the study period. The aim was to obtain an increase in CI greater than or equal to 30% at the end of the first hour of treatment. Excessive systemic hypotension with low SVR was treated with volume loading.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Noninvasive versus invasive assessment of cardiac output after cardiac surgery: clinical validation.

The accuracy of noninvasive cardiac output (CO) measurement techniques, such as electrical bioimpedance (BIO), suprasternal continuous-wave Doppler (CWD), pulsed-wave Doppler (PWD), and transesophageal continuous-wave Doppler (TED) ultrasound has been variably judged in recent years. In addition, clinical comparisons are hampered by the fact that there is no generally accepted gold standard in CO measurement. After coronary artery bypass surgery in 25 patients, CO was simultaneously determined by invasive standard techniques (thermodilution [TD] and Fick methods) plus BIO, CWD, PWD, and TED. There was an excellent agreement found between TD and the Fick method (COF = 0.13 + 1.01.COTD; r = 0.96; n = 99). Thermodilution was thus chosen to be the reference method. Bioimpedance underestimated COTD (COBIO = 0.47 + 0.60.COTD; r = 0.78; n = 111). Allowing physiological ejection times only led to an improved agreement between BIO and TD (COBIO = 0.05 + 0.69.COTD; r = 0.82; n = 79), but BIO still significantly underestimated COTD (P less than 0.0005). Using physiologic ejection times during COCWD determination reduced the scatter of data as compared with TD; however, CWD still considerably overestimated COTD, when COCWD computation was based on the echocardiographic aortic diameter (ECHO) (COCWD ECHO = 0.79 + 1.40.COTD; r = 0.84; n = 52). With the surgical aortic diameter (SURG), the agreement improved (COCWD SURG = 0.75 + 1.16.COTD; r = 0.89; n = 44), but overestimation of COTD remained significant (P less than 0.05). Irrespective of the aortic diameter, COPWD values showed a considerable scatter of data compared with COTD (COPWD ECHO = 1.26 + 0.60.COTD; r = 0.62; n = 64 and COPWD SURG = 1.42 + 0.41.COTD; r = 0.47; n = 61). Correlation of absolute COTED values to thermodilution depended on the method used for calibration. All investigated noninvasive CO measurement techniques unreliably measured relative CO changes. Despite its invasiveness, TD remains the method of choice for accurate CO determination in adult patients following cardiac surgery.

Adult↗
PubMed1992

Haemodynamic and biological effects of intravenous milrinone in patients with a low cardiac output syndrome following cardiac surgery: multicentre study.

The haemodynamic and biological effects of intravenous milrinone were studied in 24 adult patients with a low cardiac output syndrome following cardiac surgery. The patients received a milrinone bolus of 50 micrograms kg-1 over 10 min followed by a 0.375-0.750 micrograms kg-1 min-1 infusion over 48 h. After the first hour of treatment, an increase in cardiac index, systolic index and left ventricular stroke work index, and a decrease in right and left loading pressures, pulmonary artery pressure, systemic vascular resistance and pulmonary vascular resistance were observed while heart rate and systemic arterial pressure were not modified. These haemodynamic effects were maintained over the 48 h of treatment and persisted 3 h after discontinuation of treatment. Milrinone, which possesses inotropic and vasodilatory effects, increased cardiac performance and corrected the low cardiac output in all patients.

Adult↗
PubMed1979

Pituitary-gonadal dysfunction in low-output cardiac failure.

Diminished cardiac output and digoxin therapy appear to have opposing effects on testosterone, oestradiol and luteinizing hormone concentrations. Depression of the levels of these hormones was significantly correlated with a decrease in cardiac index and elevation was noted by digoxin therapy of long duration. The effect of cardiac output is most marked on testosterone and that of digoxin on oestradiol.

Adult↗
PubMed1992

Haemodynamic effects of different doses of dopexamine hydrochloride in low cardiac output states following cardiac surgery.

We studied the haemodynamic effects of dopexamine hydrochloride, a beta 2-adrenergic agonist with dopaminergic (DA1) activity, in 20 patients with low cardiac output following surgery for coronary artery bypass grafting and/or valve replacement or repair. Following titration of four doses (1, 2, 4 and 6 micrograms.kg-1.min-1), the dose producing the optimal response was infused for up to 48 h (five patients). During the infusion, significant increases in cardiac index and stroke volume were accompanied by significant decreases in systemic vascular resistance. Heart rate increased significantly up to 6 h and thereafter returned to control levels. Mean blood pressure was reduced but did not fall below 60 mmHg. However, in five patients treated for 48 h mean blood pressure had returned to control levels. Unwanted effects (tachycardia and hypotension) were seen chiefly at higher doses, leading us to conclude that infusion rates of 4 micrograms.kg-1.min-1 or less will be useful in the treatment of low cardiac output following cardiac surgery.

Adrenergic Agonists↗
PubMed1990

Transesophageal Doppler ultrasonography: evidence for improved cardiac output monitoring.

Cardiac output monitoring by transesophageal Doppler ultrasound has not gained wide clinical acceptance. A recently developed transesophageal Doppler device, Accucom 2, features technological advances aimed to reduce the error of this approach to the monitoring of cardiac output. To determine if Accucom 2 enables more accurate cardiac output monitoring, a prospective investigation was undertaken. Analyses of 923 simultaneous measurements of transesophageal Doppler and thermodilution cardiac output in 47 anesthetized patients were compared. Results using Accucom 2 were highly correlated with the results obtained with thermodilution (R = 0.91) and provided significantly greater accuracy in comparison with a previously developed Doppler cardiac output monitor, Accucom 1. Technological advances in transesophageal Doppler ultrasound hold promise for clinically useful noninvasive monitoring of cardiac output.

Aged↗
PubMed1976

Determinants of variation between Fick and indicator dilution estimates of cardiac output during diagnostic catheterization. Fick vs. dye cardiac outputs.

Simultaneous Fick and duplicate dye cardiac outputs were done in 105 patients with various cardiovascular diseases during routine cardiac catheterization. Dye was injected into the pulmonary artery and sampled from the brachial artery. Nineteen patients had mitral and/or aortic valvular regurgitation. Eighty-four per cent of the duplicate dye cardiac outputs agreed within 10 per cent variation from the line of identity, and 98 per cent were within 25 per cent. There was no systematic difference between the Fick and dye methods. Seventy-five per cent agree within 20 per cent variation from the line of identity. However, individual variation ranged from -27 to +58 per cent. There was, also, no systematic difference between Fick and dye methods either with low cardiac index or valvular regurgitation. Variation between the two methods was less with low cardiac index and greater with higher cardiac index. The variation was not increased in the presence of valvular regurgitation. The variation in the two methods could partly be explained by errors in the measurement of arteriovenous oxygen difference and oxygen consumption. When the injection is made into the pulmonary artery and sampled from the brachial artery, dye outputs are valid irrespective of the level of resting cardiac index and valvular regurgitation as long as there are enough points to draw a straight line from semilogarithmic trace of the descending limb.

Cardiac Catheterization↗
PubMed1979

Simple method for measurement of cardiac output by thermodilution after cardiac operation.

Cardiac output by the thermodilution technique was measured by a new No. 2 Fr. transthoracic (2F-TT) thermistor catheter placed at cardiac operation into the pulmonary artery directly through the right ventricular outflow tract. Cold (0 degree C) 5% dextrose in water (D5W) was used as indicator and injected through a percutaneously placed central venous pressure (CVP) catheter in the jugular vein. Comparison to the No. 7 Fr. Swan-Ganz (7F-SG) catheter demonstrated a close correlation (r = 0.87) and almost identical mean thermodilution cardiac output values during 530 determinations in 10 patients. No difficulty was experienced in insertion or removal of the 2F-TT catheter and no bleeding complications were noted. Experiments in six dogs showed that variation in position of the tip of the CVP catheter within the superior vena caval venous system and right atrium was not a critical factor in measurement of thermodilution cardiac output. The thermodilution cardiac output technique in general and the ease of insertion, as well as the small size of the 2F-TT catheter, should make this method especially advantageous in infants and small children.

Cardiac Output↗
PubMed1992

Induced hypothermia in the management of refractory low cardiac output states following cardiac surgery in infants and children.

Post-operative low cardiac output states remain a major cause of mortality following cardiac surgery in infants and children. Since 1979 we have used moderate induced whole-body hypothermia in the management of low-output states refractory to conventional modes of therapy. This is based not only upon the relationship between body temperature and oxygen consumption, but also on experimental work showing a beneficial effect of cooling upon myocardial contractility, particularly when there is pre-existing impairment of ventricular function. Between July 1986 and June 1990, 20 children with refractory low-output states were cooled by means of a thermostatically controlled water blanket to a rectal temperature of 32-33 degrees C. The median age was 12 months (1 week-11 years) with a median weight of 6 kg (3.5-33 kg). Ten children survived to leave hospital while a further two made a haemodynamic recovery. There was a marked reduction in heart rate (P < 0.001). The mean arterial pressure rose (P = 0.037) while there was a fall in mean atrial pressure (P < 0.001). There was a significant improvement in the urine output (P = 0.002). A fall in the platelet count (P < 0.001) was not accompanied by any change in the white cell count (P = 0.15). Although it is impossible to say whether cooling influenced the outcome in any of these children, it was usually effective in stabilising their clinical condition. The technique is simple and has a sound theoretical basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output, Low↗
PubMedDate not supplied

Left heart assist device: early clinical experiences with management of postperfusion low cardiac output.

Low cardiac output is a continuing cause of mortality after intracardiac operation in patients coming to surgery with advanced myocardial dysfunction. A simple method using a left heart assist device (LHAD) after open heart surgery to manage low cardiac output resistant to all adjuvant therapy is described. Except for the special cannulas, all equipment necessary for the LHAD is available in any unit performing open-heart surgery. Fifteen patients who could not be separated from conventional cardiopulmonary bypass underwent postoperative support with the LHAD (up to 501 hours). Ten patients were weaned from the device and 6 were dismissed from the hospital. Four patients remain alive, the longest period after operation being 24 months. A major asset of the LHAD is that thoracic reentry is not required at termination of LHAD support, since their design permits the cannulas to remain permanently in situ. This is thought to be an important concept, since critically ill patients requiring support are precisely those in whom added risk would be imposed by a second operation.

Adult↗
PubMed1990

Management of low cardiac output syndrome after cardiac surgery using enoximone.

This case report describes the use of enoximone, a potent phosphodiesterase F-IV inhibitor with inotropic and vasodilator actions, to treat low output syndrome after cardiac surgery. The reduced cardiac output was unresponsive to a combination of inotropic drugs and intra-aortic balloon counterpulsation was contraindicated. Cardiac output was increased dramatically by enoximone, but systemic vascular resistance and perfusion pressure remained low until the addition of metaraminol.

Aged↗