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At least 1,009 records · Page 56Linked to original sources
PubMed1999

Influence of lower limb pneumatic compression on pulmonary artery temperature: effect on cardiac output measurements.

OBJECTIVES: To characterize the decreases in pulmonary artery temperature that coincide with the inflation cycle of pneumatic calf compression stockings and to examine their effects on the thermodilution measurement of cardiac output. DESIGN: Three-part observational study. SETTING: University hospital surgical intensive care unit. PATIENTS: Postoperative patients with indwelling pulmonary artery catheters. INTERVENTION: Thermodilution cardiac output measurements with and without pneumatic calf compression. MEASUREMENTS AND MAIN RESULTS: Phase 1 (n = 18) examined the effects of pneumatic compression on pulmonary artery temperature. There was no effect on pulmonary artery temperature (device off, 37.468+/-0.008 degrees C; device on, 37.458+/-0.014 degrees C), but the difference between the maximum and minimum pulmonary artery temperatures was increased (off, 0.031+/-0.006 degrees C; on, 0.055+/-0.012 degrees C [p < .001]). Phase 2 (n = 12) found that the mean thermodilution cardiac output with 10 mL of cold (0-5 degrees C) injectate was unchanged by pneumatic compression (off, 7.00+/-2.28 L/min; on, 6.89+/-2.22 L/min). However, when the compression devices were operating, the variability between the individual measurements was increased, as reflected by larger coefficients of variation (off, 3.19+/-1.96; on, 8.72+/-6.56 [p < .02]). Similar results were obtained during phase 3 (n = 5), when cardiac output was measured with room temperature Injectate. CONCLUSIONS: Intermittent pneumatic calf compression increased lower limb venous return, causing acute but transient decreases in pulmonary artery blood temperature. This did not affect the accuracy of thermodilution cardiac output measurements that were made using 10 mL of either cold or room temperature injectate.

Bandages↗
PubMedDate not supplied

[Extrauterine adaptation: cardiac output changes in different modes of delivery. Preliminary results].

Cardiac output in two homogeneous populations of term newborns, by spontaneous delivery and cesarean section without labour, has been estimated at 2, 24, 48, 72 and 96 hours after birth. Changes has been noticed in Cardiac Output in the first day of life and between different mode of delivery. Larger charges has been noticed in spontaneous then in cesarean delivery.

Adaptation, Physiological↗
PubMed1983

Single catheter technique for accurate cardiac outputs from left ventricle.

We report our experience in cardiac output measurements using a single catheter for left ventricular green dye injection with sampling from the side arm of a femoral artery introducer sheath. This technique is compared to thermal dilution (20 patients) and pulmonary artery green dye injection (20 patients). There were no significant differences between the single catheter left ventricular method and the other two accepted methods for measuring cardiac output.

Cardiac Catheterization↗
PubMed1996

Effects of cardiac output on disposition kinetics of sorbitol: recirculatory modelling.

1. The purpose of this study was to determine the effects of cardiac output on distribution and elimination kinetics of the marker compound sorbitol. 2. The disposition kinetics of sorbitol were investigated after rapid intravenous injection and arterial sampling in nine patients who had undergone cardiac catheterization whereby the cardiac output was measured. 3. A minimal circulatory model consisting of pulmonary and systemic subsystems, both of which were characterized by an inverse Gaussian transit time density function, fitted the data very well. The method involves numerical inverse Laplace transform of the model equations. 4. The mixing clearance introduced as a novel non-compartmental parameter of distribution dynamics was significantly correlated with cardiac output. The steady-state volume of 14 l matched the extracellular volume. The systemic extraction ratio of 23% may reflect the fractional liver blood flow. 5. This pharmacokinetic model can be applied when an independent observation of cardiac output is available. In contrast to the conventional compartmental (or sum of exponential) approach it contains fewer adjustable parameters which can be more readily interpreted in physiological terms.

Aged↗
PubMed1988

[Effects of positive expiratory pressure on cardiac output and estimated hepatic blood flow during controlled ventilation in man].

This study aimed to discover the effects of artificial ventilation with positive end-expiratory pressure (PEEP) on cardiac output and hepatic blood flow in ten patients with chronic stable post-anoxic or post-traumatic coma, without any cerebral oedema or any other visceral pathology. This study was carried out at four levels of end-expiratory pressure (0, 5, 12 and 29 cmH2O) and after 24 h of artificial ventilation with a PEEP arbitrarily fixed at 12 cmH2O. Cardiac output was measured by thermodilution and hepatic blood flow by applying Fick's principle on a continuous infusion of indocyanine green with an analysis of suprahepatic venous samples. Hepatic blood flow is given by the amount of indocyanine green infused (0.5 mg.min-1) divided by the difference between arterial and suprahepatic venous indocyanine green concentration. For all levels of PEEP, mean arterial, right atrial, wedge and suprahepatic pressures and hepatosplanchnic resistances were measured. Artificial ventilation with PEEP induced a fall of cardiac output and hepatic blood flow proportional with the increase in PEEP level. The fall in hepatic blood flow began to be statistically significant for a PEEP level of 5 cmH2O (-17%; p less than 0.01) and was maximum for a PEEP of 20 cmH2O (-49.51%; p less than 0.001). There was no linear correlation between cardiac output and hepatic blood flow: the fall in hepatic blood flow was more important than the fall in cardiac output. These changes in hepatic blood flow were accompanied by a significant increase in hepatosplanchnic resistances (p less than 0.01 for PEEP = 12 cmH2O), without any changes in other haemodynamic parameters or biological signs of hepatic disturbance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2001

The effects of lactated Ringer's solution infusion on cardiac output changes after spinal anesthesia.

UNLABELLED: We evaluated the effects of an infusion of lactated Ringer's (LR) solution on changes in cardiac output (CO) after spinal anesthesia. Seventy-five patients scheduled for lower extremity surgery under spinal anesthesia were studied. We measured CO (impedance cardiography method) and blood pressure for 25 min before and 30 min after spinal anesthesia. Patients were randomly assigned to three groups. In the No Infusion group, no LR solution was given during the period of measurements. The LR Before group received 12 mL/kg of LR solution within 20 min before spinal anesthesia. The LR After group received 12 mL/kg of LR solution within 20 min starting immediately after spinal anesthesia. After spinal anesthesia, CO decreased by 13.9% in the No Infusion group. In the LR Before group, CO increased after the infusion by 20% and returned to baseline value 30 min after spinal anesthesia. In the LR After group, CO increased after spinal anesthesia, and 30 min after spinal anesthesia, CO was 11.3% above baseline. We conclude that the decrease in CO after spinal anesthesia can be prevented by the infusion of an LR solution, with CO reaching the highest value while the infusion is running. IMPLICATIONS: We studied the effects of lactated Ringer's solution infusion on cardiac output changes after spinal anesthesia. If the patients received no infusion, cardiac output decreased after spinal anesthesia. However, if the patients received lactated Ringer's solution infusion, cardiac output was maintained.

Adult↗
PubMed1982

Cardiac output changes during Caesarean section. Measurement by transcutaneous aortovelography.

A non-invasive technique of measuring cardiac output changes is described and studies of its accuracy and reproducibility are reviewed. Cardiac output changes in 11 patients undergoing Caesarean section under general anaesthesia were measured with this technique. Increases in cardiac output after induction and commencement of surgery (mean 19%, p less than 0.05), and after delivery (mean 19%, p less than 0.05) were found.

Aorta, Thoracic↗
PubMed1989

Cardiac output measurements during and after triplet gestation.

In a gravida with a triplet gestation complicated by fainting attacks and transient episodes of apparently positional hypotension, cardiac output was measured noninvasively to determine the optimal posture during cesarean section. Before delivery, cardiac output and mean arterial pressure were highest in the left semilateral position and lowest in the right semilateral posture. Shortly after delivery of the infants, cardiac output was still highest in the left semilateral position but lowest in the supine posture. Twenty-four and 48 hours later, the values were almost identical in all three positions. Noninvasive cardiac output monitoring provided a simple method of detecting the occurrence and severity of caval compression and of determining the optimal position of the gravida during cesarean section.

Adult↗
PubMed2005

Circulation time in man from lung to periphery as an indirect index of cardiac output.

Circulation time (Ct) between lung and periphery may be a surrogate for cardiac output, estimated here, for the most part, as the time between taking a breath of nitrogen and peripheral detection of a desaturation pulse. Use of pulse oximetry involves an internal, instrument delay; however, using the ear, we found shortening with exercise (12.1 +/- 0.37 sec, at rest; 9.1 +/- 0.25 sec at 100 watts), lengthening after beta-blockade, and lengthening in patients with echocardiographic and clinical left heart failure (8 patients 16.2 +/- 1.1 sec; 6 controls 12.0 +/- 0.5 sec). Pulse oximetry failed, however, to discriminate heart failure from normal in several patients. In patients referred to a department of nuclear medicine for assessment of chest pain, pulse oximetry (finger and ear) showed unacceptable variability. Nuclide delays between lung and carotid artery correlated significantly with the reciprocal of gated SPECT estimated cardiac output (Q(gs)); not so, however, for lung to finger. In normal subjects, an old Waters fast response oximeter gave short, reproducible Ct estimates and a significant correlation with the reciprocal of (indirect Fick) cardiac output (Q(if)). The relationship for normal subjects was: Ct = 0.28 x 60/Q(if) + 2.8 sec (Q(if) in L min.; P slope < .001).

Atenolol↗
PubMed1980

Comparison of dye dilution method to radionuclide techniques for cardiac output determination in dogs.

A study was undertaken to identify the most accurate 99mTc-labeled radiopharmaceutical and to determine the accuracy of a noninvasive radionuclide technique (antecubital injection and precordial detection) for cardiac output determinations. Phase I employed sodium pertechnetate, stannous pyrophosphate with sodium pertechnetate, technetium-99m red blood cells, and technetium-99m human serum albumin as radionuclide tracers. Cardiac output was determined by the dye dilution method and then by the invasive radionuclide technique. The radiopharmaceutical was injected into the same intracardiac catheter used in the dye dilution method. Seven to 10 mongrel dogs were used to test the accuracy of each radiopharmaceutical. A paired t test and regression analysis indicated that technetium-99m human serum albumin was the most accurate radiopharmaceutical for cardiac output determinations, and the results compared favorably to those obtained by the dye dilution method. In Phase II, technetium-99m human serum albumin was used as the radionuclide tracer for cardiac output determinations with the noninvasive technique. The results compared favorably to those obtained by the dye dilution method. Regression analysis indicated a correlation coefficient of 0.91. A paired t test demonstrated that the difference between the two methods was not statistically significant (p greater than 0.05). The data suggest that a noninvasive radionuclide technique using cardiac output determinations in humans.

Animals↗
PubMed2002

Non-invasive measurement of cardiac output in heart failure patients using a new foreign gas rebreathing technique.

Values of effective pulmonary blood flow (Q(EP)) and cardiac output, determined by a non-invasive foreign gas rebreathing method (CO(RB)) using a new infrared photoacoustic gas analysing system, were compared with measurements of cardiac output obtained by the direct Fick (CO(FICK)) and thermodilution (CO(TD)) methods in patients with heart failure or pulmonary hypertension. In 11 patients, of which three had shunt flow through areas without significant gas exchange, the mean difference (bias) and limits of agreement (+/- 2 S.D.) were 0.6 +/- 1.2 litre x min(-1) when comparing CO(FICK) and Q(EP), and -0.8 +/- 1.3 litre x min(-1) when comparing CO(FICK) and CO(TD). When correction for intrapulmonary shunt flow was applied (i.e. calculation of CO(RB)) in all 11 patients, the bias between CO(FICK) and CO(RB) was 0.1 +/- 0.9 litre x min(-1), primarily because agreement improved in the three patients with significant shunt flow. In the eight patients without significant shunt flow, the agreement between Q(EP) and CO(FICK) was 0.3 +/- 0.9 litre x min(-1). In conclusion, a foreign gas rebreathing method with a new infrared photoacoustic gas analyser provided at least as reliable a measure of cardiac output as did thermodilution. In the absence of significant shunt flow, measurement of Q(EP) itself provides a reliable estimate of cardiac output in heart failure patients. The infrared photoacoustic gas analyser markedly facilitates clinical use of the rebreathing method in general, which makes the method available to a larger group of clinicians working with patients with cardiovascular diseases.

Breath Tests↗
PubMed2006

Correlation between cardiac output measured by the femoral arterial thermodilution technique pulmonary arterial and that measured by contour pulse analysis in a paediatric animal model.

OBJECTIVE: To evaluate the correlation between two methods for the determination of cardiac output: the femoral arterial thermodilution technique (FATD) and the arterial pulse contour analysis (PCCO) using the PiCCO catheter. METHODS: We performed a prospective animal study using 51 immature Maryland pigs weighing 9 to 16 kg. A 4- or 5-Fr arterial PiCCO catheter was introduced into the femoral artery. In each animal, we made measurements of cardiac output at 30-minute intervals by femoral arterial thermodilution for a total of 209 measurements. We registered the previous PCCO and compared with the mean of two measures of FATD cardiac output. RESULTS: Mean FATD was 1.73 +/- 0.60 L/min and mean PCCO was 1.78 +/- 0.70 L/min (no significant difference). The mean difference (bias) of differences (limits of agreement) was 0.04. The correlation founded between the two methods was 0.786 (95% confidence interval, 0.71-0.83). CONCLUSIONS: Femoral arterial thermodilution cardiac output measurements correlates well with pulse contour analysis cardiac output in this paediatric animal model.

Aging↗
PubMed1989

Measurement of cardiac output in pregnancy by thoracic electrical bioimpedance and thermodilution. A preliminary report.

Thoracic electrical bioimpedance is a noninvasive, continuous method of obtaining cardiac output that requires no operator skill. However, the most recent thoracic electrical bioimpedance technology has not been validated in pregnancy. We therefore compared two methods of measuring cardiac output in pregnancy, thoracic electrical bioimpedance and thermodilution. We studied 11 patients who required pulmonary artery catheterization for peripartum management and measured cardiac output simultaneously by thoracic electrical bioimpedance and thermodilution. Among eight of nine patients, there was agreement (within +/- 20%) between the two methods. Bivariate linear regression with these nine cases showed excellent correlation (r = 0.91, p less than 0.001) with a slope of 1.04, which indicated a one-to-one relationship between thoracic electrical bioimpedance and thermodilution. The remaining two cases were removed from analysis because of septic shock in one case (which invalidates thoracic electrical bioimpedance) and 4+ tricuspid regurgitation in another case (which invalidates thermodilution). These data support that thoracic electrical bioimpedance measurement of cardiac output may be valid in most peripartum patients.

Cardiac Output↗
PubMed1994

Effects of the sauna on diffusing capacity, pulmonary function and cardiac output in healthy subjects.

The present study examined possible short-term effects of the heat stress during sauna bathing on gas exchange, especially in correlation with changes in cardiac output. The results obtained are as follows: (1) The heat stress of sauna bathing caused a slight but not significant increase in diffusion capacity (p = 0.239) and no change in other pulmonary function parameters. (2) Cardiac output and cardiac index increased slightly but not significantly (p = 0.2455 and p = 0.2719). We conclude that heat stress in sauna neither influences gas exchange nor does it cause a significant increase in cardiac output.

Adolescent↗
PubMed1988

[Left and right ventricular cardiac outputs in early neonatal periods examined using Doppler echocardiography].

To evaluate early neonatal circulatory adaptation, left and right ventricular cardiac outputs were examined in 10 normal neonates using Doppler echocardiography. Serial examinations were performed until ductal closure was confirmed. Two-dimensional echocardiography and Doppler echocardiography were used to evaluate structures of the heart and great vessels and flow within them. Then, the diameters of the ascending aorta (dAo) and pulmonary artery (dPA) were measured using M-mode echocardiography. The flow velocity patterns of the ascending aorta and pulmonary artery were recorded, measuring mean aortic (VAo) and pulmonary artery velocities (VPA). Left (LVCO) and right ventricular cardiac outputs (RVCO) were calculated as follows: LVCO = (dAo)2/4 x pi x VAo x 60, RVCO = (dPA)2/4 x pi x VPA x 60. 1. Patency of the ductus arteriosus was confirmed by the shunt through it in all neonates initially examined. The initial velocity pattern of the ductal shunts was bidirectional (9/10) or continuous left-to-right (1/10). The flow velocity pattern changed to continuous left-to-right in most neonates, and spontaneous closure of the ductus was confirmed at the age of 13 to 64.5 (mean 31.4) hrs. 2. Left-to-right shunt through the stretched foramen ovale was noted in six neonates temporarily. 3. As for the arterial diameter, dAo did not change, but dPA decreased at the time of spontaneous closure of the ductus. 4. Concerning mean aortic velocity, VAo increased when a continuous ductal left-to-right shunt was initially suspected, while VPA increased when spontaneous closure of the ductus was confirmed. 5. For cardiac output, LVCO (ml/min) changed from 618.4----718.3----562.7, while RVCO showed no change (576.1----546.5----557.8) according to a ductal flow change from bidirectional to continuous left-to-right and finally to no shunt. The LVCO/RVCO ratio increased with increasing age and (in 7/9) the maximal rate was noted when the continuous left-to-right ductal shunt was confirmed. The increased LVCO contributed to the increased LVCO/RVCO ratio. Using this method, serial evaluations of two ventricular cardiac outputs could be made.

Aorta↗
PubMed1990

[Catecholamines in the treatment of the low cardiac output syndrome following heart surgery with extracorporeal circulation].

The aim of this study was to estimate the effectiveness of different mono- and combination therapies with catecholamines (dopamine, dobutamine, adrenaline and noradrenaline) in the treatment of low cardiac output syndrome after open-heart surgery. All together 425 patients treated at the Intensive Care Unit of the Clinic for Anaesthesiology and Intensive Care Therapy of the Martin Luther University Halle-Wittenberg after open-heart surgery from 1985-1986 were examined. The low cardiac output syndromes were characterised by the following parameters: mean arterial pressure (MAP), heart frequency (HF), central venous pressure (CVP), diuresis and mixed venous oxygen saturation (SvO2). Recommendations were given for evaluating the grade of low cardiac output syndrome and for selecting whether a mono- or a combination therapy is necessary and which dose should be given. Thus, the pretherapeutical signs MAP 50 mm Hg and presence of 3 disturbed signs characterise severe low cardiac output syndrome and make necessary the primary combined application of catecholamines. Two investigated signs connected in a mathematical formula can help to determine when during a low-cardiac output state a dopamine-monotherapy should be replaced by a combination therapy of catecholamines. It was found, that the doses of dopamine increased proportionally to the reached level of catecholamine combination. Therefore, doses of catecholamines should be kept in their recommended range with their specific receptor-mediated effect.

Cardiac Output, Low↗
PubMed1999

Continuous monitoring of cardiac output in neonates using an intra-aortic Doppler probe.

Continuous monitoring of cardiac output in neonates would be of considerable benefit but, as yet, there is no practical method to achieve this aim. We have now evaluated the feasibility of using an intra-aortic Doppler probe. We introduced a pulsed Doppler probe of 0.46 mm diameter via the umbilical artery in two term and four preterm neonates. Indications in all patients for umbilical arterial catheter is always an unstable cardiopulmonary state. Body weights were between 770 and 3340 g. Velocities of blood flow in the thoracic aorta were continuously recorded to estimate cardiac output on-line for 12 h. No complications were encountered. It proved possible to derive high-quality Doppler curves. The received Doppler signal was stable but it proved sensitive to pathophysiologic changes in flow. Mean velocity of flow in the descending aorta was 16.4 cm/s (range 13.3-19.0 cm/s). We quantified flow by multiplying the mean velocity of the flow by the cross-sectional area of the descending aorta. Calculated mean flow was 135 ml/kg/min (range 111-179 ml/kg/min). These values are consistent with those measured by transcutaneous Doppler, and it should not be raised by left-to-right ductal shunts. This pilot study proved the feasibility of continuous monitoring of cardiac output. The technique should prove of great value in those infants with unstable circulatory conditions, and can be used even in infants with extremely low birth weights.

Cardiac Output↗
PubMed1976

The effect of hypoxia on the regional distribution of cardiac output in the dog.

Twenty-one dogs were studied under conditions of normal oxygenation and hypoxia with the microsphere distribution method to determine the effect of arterial oxygen saturation on the regional distribution of cardiac output. The dogs were anesthetized and artifically ventilated. Cannulas were placed in the left ventricle to administer microspheres and in a peripheral artery to determine cardiac output. Each dog received two microsphere injections: (1) while normally oxygenated (room air), and (2) under hypoxia (10% oxygen-90% nitrogen in 10 dogs and 5% oxygen-95% nitrogen in 11 dogs). Absolute cardiac output increased from 87 +/- 15 ml/min per kg to 101 +/- 14 ml/min per kg during mild hypoxia (10% oxygen) (P less than 0.05), and from 73 +/- 17 ml/min per kg to 120 +/- 24 ml/min per kg during severe hypoxia (5% oxygen) (P less than 0.01). Absolute blood flows increased to all organs except skin and muscle during hypoxia, although there were decreases in the fractional distribution of cardiac output to the splanchnic bed and kidney. Striking changes were found in coronary, hepatic, and cerebral circulation, and the organ with, greatest response to hypoxia was the heart, with increased coronary flow of 37% and 285% during exposure to 10% and 5% oxygen, respectively. Hence, low oxygen levels in blood cause redistribution of cardiac output and arterial content plays an important role in blood flow regulation.

Animals↗