Measurement Of Hemodynamic Parameters Research Articles

Exercise Doppler echocardiography as an aid to clinical decision making in mitral valve disease.

The timing of valve replacement in patients with mitral valve disease, severe resting pulmonary hypertension, and severe symptoms is usually straightforward. However, this may not be true for patients with mild to moderate resting pulmonary pressures and symptoms that are difficult to evaluate. The measurement of hemodynamic parameters with exercise has been useful during cardiac catheterization. The purpose of this study was to evaluate the hemodynamic significance of dyspnea provoked by exercise in patients with mitral valve disease using exercise Doppler echocardiography. Nineteen tests were done in 17 patients (two patients had repeat studies 1 year after the first test). Dyspnea developed in patients during exercise in 11 tests, and the others were limited by fatigue (and angina in one patient). There was a significantly greater increment in pulmonary artery systolic pressure during exercise in the patients who developed dyspnea (24 mm Hg) than in those who did not (15 mm Hg, p = 0.04). The two groups exercised to approximately the same heart rate and blood pressure, but the dyspneic patients had a significantly shorter exercise capacity (p = 0.04). Furthermore, clinical decision making was affected by the test results in 84% (only three tests did not affect patient management) and included a decision to proceed to invasive testing and surgery in seven patients, and a decision to treat the patient medically in nine. In conclusion, exercise Doppler echocardiography is a useful adjunct in the diagnosis and treatment of patients with mitral valve disease and an aid to clinical decision making.

Right ventricular dynamic cardiomyoplasty: an experimental model

The effectiveness of dynamic cardiomyoplasty as a means of haemodynamic support in heart failure remains controversial. We have undertaken a study of right ventricular dynamic cardiomyoplasty in sheep using intravenous propranolol to provoke heart failure. Muscle conditioning was performed with cardiomyostimulators following a previously established protocol. We performed multiple invasive measurements of haemodynamic parameters including arterial blood pressure, cardiac output, pulmonary artery capillary wedge pressure, right ventricular dp/dt and end diastolic pressures. These were performed before induction of heart failure, after induction of heart failure, and with pacing of the cardiomyoplasty flap in established heart failure. Our results confirm that we were able to establish significant heart failure and that subsequent pacing of the conditioned muscle flap was able to return cardiac output and right ventricular function to their pre-failure control levels.

Hemodynamic and coronary vasodilative action of two nitroglycerin oral spray formulations

This study compared glycerol trinitrate (NTG) oral spray in a new hydrophilic formulation with a reference aerosol in a lipophilic base with respect to the time to onset of action on hemodynamics and on the coronary vasomotor tone. Differences in the profile of action between the two spray formulations were assessed in two groups of ten patients each. In each of the two groups the patients were randomly assigned to receive 0.8 mg of aerosolized NTG in either the hydrophilic or lipophilic base in double-blind fashion. The patients of group A had stable, exercise-induced angina pectoris, in whom responses to the sprays were evaluated under resting conditions. The patients of group B were suspicious of vasospastic or mixed form of angina pectoris, in whom the effects of the sprays were studied under diagnostic ergonovine provocation. The onset and extent of action of the sprays were assessed by serial measurements of hemodynamic parameters and repeat quantitative coronary angiography. The two formulations of NTG oral spray had a comparably potent coronary vasodilator effect in patients under resting conditions and under ergonovine provocation. As far as hemodynamic action is concerned, the new hydrophilic spray exerted its hemodynamic effect more rapidly than the lipophilic spray. Thus, the new NTG oral spray promises to afford therapeutic advantages for the relief of anginal attacks as well as hemodynamic unloading in congestive heart failure and acute pulmonary hypertension.

Using Hemodynamic Waveforms to Assess Cardiopulmonary Pathologies

The pulmonary artery catheter brought measurement of hemodynamic parameters to the bedside in the early 1970s. The critical care clinician has been able to obtain direct and derived parameters that have proved useful in the diagnosis, management, and evaluation in various clinical conditions. The evaluation of the mechanical events in the heart, as evidenced through accurate interpretation of waveform configuration, has enhanced the diagnostic ability of the clinician. A wide variety of cardiopulmonary conditions can be recognized, including valvular defects, shunts, electrical disturbances and others, which allow the clinician to optimize hemodynamic function and impact patient survival.

Surgical thrombectomy versus conservative treatment for deep venous thrombosis; Functional comparison of long-term results

It is known that deep venous thrombosis (DVT) of the ilio-femoro-popliteal axis is frequently associated with irreversible damage to valvular competence of the veins and consequently with varying degrees of chronic venous insufficiency. Because preservation of the valvular function of deep veins can play an important role in preventing the postphlebitic syndrome we analysed and compared the long-term functional outcome of two equally large cohorts of patients treated either surgically for restoration of venous patency and valvular function (24 patients) or medically with heparin, oral anticoagulants and compression stockings (25 patients). The study was also intended to examine the impact of duration and extent of DVT as predictive factors of late outcome. Follow-up time was 7.6 and 7.9 years respectively, operative mortality nil. Assessment of venous function was based on clinical observations as well as on measurement of haemodynamic parameters. Non-fatal pulmonary embolism after onset of treatment occurred in both cohorts with an equal frequency of 13%. Patients operated on for ilio-femoral DVT were with few exceptions totally independent of any form of adjunctive hosiery which was in sharp contrast to the conservatively managed group. If onset of DVT had occurred more than 3 days earlier and extended from the ilio-femoral axis to the popliteo-crural level, surgery usually failed and patients were no better off than in the comparable medical group. The same pattern of late outcome was found for all other clinical and haemodynamic parameters; i.e. clinical signs of venous hypertension, valvular competence as judged by sonography, patient's self-assessment and the expelled volume and refilling time measured by dynamic plethysmography after standardised leg work. The mean expelled volume was 1.1 +/- 0.5 ml/100 g/min. for the surgical group treated early for ilio-femoral DVT and 0.7 +/- 0.5 ml/100 g/min for the corresponding medical group (P = 0.05). Recovery or refilling time was 50 +/- 21 s for the surgical group and 28 +/- 26 s for the medical group (P = 0.03). Thus, the clinical and haemodynamic effect of surgical thrombectomy was significantly superior to conservative management in ilio-femoral thrombosis treated within 3 days. For extensive thrombosis treated early the advantage of surgical thrombectomy was also evident, but the difference between the two treatment groups was not significant. The advantage of surgery was however totally lost in patients operated on for extensive DVT of long duration (i.e. greater than 3 days).(ABSTRACT TRUNCATED AT 400 WORDS)

Coronary artery ligation and reperfusion in rabbits made diabetic with alloxan.

The biochemical and functional changes associated with ligation (40 min) of the left circumflex coronary artery and subsequent reperfusion (60 min) in the rabbit made diabetic with alloxan were studied and compared with those of control animals. Measurement of haemodynamic parameters revealed that both left ventricular pressure and mean arterial pressure were significantly (P less than 0.05) decreased after ligation and reperfusion in the diabetic animals compared with controls. Analysis of subcellular organelle enzyme markers from the ischaemic tissue revealed that sarcolemmal Na+,K+-ATPase, mitochondrial ATPase and sarcoplasmic reticulum ATPase activities were decreased after ligation to the same extent in the diabetic and control animals. However, upon reperfusion, the recovery of mitochondrial ATPase activity was significantly (P less than 0.05) less in the diabetic animals than in the controls. Ion measurements revealed a significant (P less than 0.05) depletion of Mg in diabetic hearts before ligation, and this was augmented during reperfusion. In contrast, a significantly (P less than 0.05) higher calcium accumulation was observed upon reperfusion in the hearts of diabetic animals. Similarly, both tissue ATP levels and the ability of the mitochondria to generate ATP were depressed to a greater degree in the diabetic animals. Our results indicate, therefore, a greater susceptibility of the diabetic myocardium to ischaemic/reperfusion injury which in the clinical situation would exacerbate the problems associated with atherosclerosis and possibly contribute to the high mortality from cardiovascular complications in diabetic patients.

90 CORRELATION OF CARDIAC HEMODYNAMICS AND BIOENERGETICS USING PHOSPHORUS NMRSPECTROSCOPY

A model for the study of cardiac phosphate metabolism in vivo is presented which provides simultaneous measurement of hemodynamic parameters and myocardial phosphate metabolites including phosphocreatine(PCr), ATP and inorganic phosphate(Pi). Anesthetized beagles were instrumented to provide: aortic, left ventricular, pulmonary artery, and pulmonary artery wedge pressures and allow cardiac output determinations by thermal dilution. Pacing wires provided control of heart rate. Spectroscopy was performed using a 1.9 Tesla large bore magnet with a one inch surface coil placed directly on the left ventricular free wall via a left thoracotomy. Cardiac gaiting provided spectrographic data at any point in the cardiac cycle. Ten animals had resting gaited studies and four had gaited studies during periods of increased myocardial demand produced with isoproterenol (2) or hypoxemia, PaO2 35-40 mmHg (2). No significant change in the ratio of PCr/Pi or PCr/ATP occurred at any point during the cardiac cycle at rest or during stress. During graded hypoxia PCr/Pi and PCr/ATP levels remained stable until a PaO2 of 20-25 mmHg at which time cardiovascular shock occurred. These preliminary data demonstrate the wide range over which the normal heart can meet its metabolic demands and suggest that similar models may provide an in vivo method for the evaluation of high energy phosphate metabolism in acquired and congenital states of cardiac dysfunction.

Effects of ethanol ingestion on amino acid uptake in the dog liver in vivo.

The effect of ethanol ingestion on the uptake of labeled amino acids was studied in the in situ autoperfused dog liver. Ethanol was administered orally, as a 15% water solution, in a dose of 4 g/kg body weight/day as the only source of water for 2 days. Amino acid uptake was measured in anesthetized dogs by means of the single-passage, multiple-tracer dilution technique. In control animals, hepatic uptake of 14C-glycine, 3H-alpha-aminoisobutyric acid (3H-AIB) and 3H-L-leucine were 50, 15 and 66%, respectively. In the ethanol-treated dogs, glycine and AIB uptake was reduced by 70 and 63%, respectively. L-leucine uptake was reduced by only 23%. The plasma concentration of the naturally occurring amino acids was significantly increased after ethanol treatment, probably due to a reduced influx into hepatocytes. Simultaneous measurements of hemodynamic parameters showed a significant increase in the portal vein pressure of ethanol-treated animals, whereas the portal vein blood flow and hepatic extracellular volume were unaffected.

Effects of oleic acid on pulmonary capillary leak and thromboxanes

The role of arachidonic acid metabolites in oleic acid-induced lung injury in anesthetized dogs was investigated. Oleic acid was administered as a bolus injection into the pulmonary artery in the following dose sequence: 0.05, 0.10, and 0.20 ml/kg at 30, 60, and 120 min, respectively, after either indomethacin (10 mg/kg iv) or vehicle. A control group ( n = 3) received normal saline instead of oleic acid. Measurements of hemodynamic parameters, mean systemic (MAP), pulmonary capillary wedge, and pulmonary artery pressures (PAP), cardiac output, arterial blood gases, extravascular lung waters (EVLW) by thermaldye double indicator dilution techniques and plasma immunoreactive thromboxane B 2 (iT×B 2), by radioimmunoassay were obtained at zero time (baseline) and 20 min following each oleic acid injection. A new noninvasive technique was employed to measure pulmonary capillary protein leak by the scintigraphic analysis of intravenously administered technetium-99m radiolabeled human serum albumin ( 99mTc-HSA) in the cardiac and lung regions. Oleic acid injection caused a significant dose related fall in MAP ( P < 0.0002), arterial pO 2 ( P < 0.0001), and cardiac output ( P < 0.001), and increases in EVLW ( P < 0.003) and plasma iT×B 2 ( P < 0.02) in the vehicle pretreated animals, while mean PAP remained unchanged. In contrast, in the indomethacin pretreated dogs, MAP, EVLW, cardiac output, and plasma iT×B 2 levels did not change from baseline values and there was an increase in mean PAP. Pulmonary vascular resistance was significantly elevated ( P < 0.05) in both groups. Compared to the control group, significant pulmonary capillary protein leaks occurred at the 0.10 ( P < 0.05) and 0.20 ( P < 0.01) ml/kg oleic acid doses in the vehicle pretreated dogs. Indomethacin failed to prevent the pulmonary capillary protein leak. There was a significant ( P < 0.02) correlation ( r = 0.72) observed between plasma iT×B 2 levels and maximal percentage protein leaks for the combined indomethacin and vehicle pretreated dogs. It was concluded that thromboxanes may serve as markers of oleic acid-induced lung injury but do not appear to mediate the resultant changes in pulmonary microvascular permeability.

Effects of ribose on cardiac metabolism and function in isoproterenol-treated rats.

Continuous iv infusion of ribose for 5 h in unanesthetized and unrestrained rats treated with isoproterenol (25 mg/kg sc) further enhanced the available pool of 5-phosphoribosyl-1-pyrophosphate and the biosynthesis of adenine nucleotides in the myocardium. The increase in adenine nucleotide biosynthesis was of such an extent that the isoproterenol-induced decline of the ATP level (mumol/g) was attenuated after 5 h (isoproterenol + ribose infusion 4.0 +/- 0.2, n = 10; isoproterenol + NaCl infusion 3.5 +/- 0.1, n = 23; control 4.5 + 0.1, n = 38) and prevented after 24 h (isoproterenol + ribose infusion 4.6 +/- 0.3, n = 5; isoproterenol + NaCl infusion 3.2 +/- 0.1, n = 9). Ribose, however, did not affect the isoproterenol-elicited elevation of the adenosine 3',5'-cyclic monophosphate (cAMP) and glucose 6-phosphate content nor did it influence the decline in glycogen. Thus ribose acts primarily via elevation of the cardiac 5-phosphoribosyl-1-pyrophosphate pool. Measurements of hemodynamic parameters with an ultraminiature catheter pressure transducer in intact rats anesthetized with thiobutabarbital sodium revealed that ribose infusion for at least 3 h further enhanced the isoproterenol-elicited increase in left ventricular dP/dtmax by about 20% but did not influence appreciably the rise in heart rate and the fall in left ventricular systolic pressure. Since ribose did not affect the immediate hemodynamic alterations induced by isoproterenol, it appears that it exerts its hemodynamic effects via the pronounced influence on cardiac adenine nucleotide metabolism.

Acute pharmacodynamics and pharmacokinetics of oral amrinone.

Amrinone was administered orally as a single 100-mg dose to six male patients with moderate-severe congestive heart failure to determine the acute pharmacodynamic effects and pharmacokinetics of the drug. Following right heart catherization and amrinone administration, measurements of hemodynamic parameters including cardiac index (Cl), right atrial pressure (RA), pulmonary capillary wedge pressure (PCW), and serum amrinone concentrations (SAC) were made at hourly intervals for up to 8 hours. Cl increased (29.0 per cent) significantly (P less than 0.05) at 3 hours after dose. PCW declined quickly after dose and was significantly (P less than 0.05) lower (-31.3 per cent) than control at 3 hours. RA declined gradually, and a significant (P less than 0.05) reduction (-25.2 per cent) was achieved 5 hours after the dose. Amrinone was absorbed quickly (tmax = 1.4 hour), and the disappearance of amrinone from serum was log-linear (t1/2 = 5.1 hours). The time courses of per cent change in Cl and SAC were similar, and the correlation between the average per cent change in Cl and average SAC was linear and significant (r = 0.80; P less than 0.05).

Oxygen-High Dose Fentanyl-Droperidol Anesthesia for Aortocoronary Bypass Surgery

Ten patients undergoing aortocoronary bupass surgery were studied during induction of anesthesia and during initial surgical stimulation. Each patient was anesthetized with fentanyl, 100 micrograms/kg, droperidol, 0.15 mg/kg, and pancuronium, 0.1 mg/kg, and ventilated with 100% oxygen. Preoperative medication consisted of propranolol, nitrate preparations, diazepam, 0.15 mg/kg orally, morphine, 0.15 mg/kg IM, and scopolamine, 0.4 mg IM. Intravenous, arterial, and Swan-Ganz catheters were inserted under local anesthesia after which control measurements of hemodynamic parameters and arterial blood gas tensions were taken. Observations were repeated after fentanyl, 50 micrograms/kg, after endotracheal intubation, after another dose of fentanyl, 50 micrograms/kg, after skin incision, and after sternotomy. The total dose of droperidol was given incrementally throughtout the fentanyl infusion. Normal saline was infused to maintain constant pulmonary capillary wedge pressure. Heart rate, left ventricular stroke work index, triple index, pulmonary capillary wedge pressure, and PaCO2 remained constant throughout the study. Systolic blood pressure decreased significantly after fentanyl, 50 micrograms/kg, and initial administration of droperidol, but thereafter remained unchanged. Stroke index increased significantly after fentanyl, 50 micrograms/kg, and remained elevated at all subsequent intervals. Cardiac index increased after fentanyl, 50 micrograms/kg and 100 micrograms/kg. Rate-pressure product was stable until the time of sternotomy after which it decreased significantly. In patients undergoing aortocoronary bypass surgery, 100% oxygen, fentanyl, 100 micrograms/kg, and droperidol, 0.15 mg/kg, produced stable hemodynamics during induction, intubation, and sternotomy. Maintenance of pulmonary capillary wedge pressure by volume infusion may have been contributed to this stability.

Oxygen-High Dose Fentanyl-Droperidol Anesthesia for Aortocoronary Bypass Surgery

Ten patients undergoing aortocoronary bypass surgery were studied during induction of anesthesia and during initial surgical stimulation. Each patient was anesthetized with fentanyl, 100 μg/kg, droperidol, 0.15 mg/kg, and pancuronium, 0.1 mg/kg, and ventilated with 100% oxygen. Preoperative medication consisted of propranolol, nitrate preparations, diazepam, 0.15 mg/kg orally, morphine, 0.15 mg/kg IM, and scopolamine, 0.4 mg IM. Intravenous, arterial, and Swan-Ganz catheters were inserted under local anesthesia after which control measurements of hemodynamic parameters and arterial blood gas tensions were taken. Observations were repeated after fentanyl, 50 μg/kg, after endotracheal intubation, after another dose of fentanyl, 50 μg/kg, after skin incision, and after sternotomy. The total dose of droperidol was given incrementally throughout the fentanyl infusion. Normal saline was infused to maintain constant pulmonary capillary wedge pressure. Heart rate, left ventricular stroke work index, triple index, pulmonary capillary wedge pressure, and PaCO2 remained constant throughout the study. Systolic blood pressure decreased significantly after fentanyl, 50 μg/kg, and initial administration of droperidol, but thereafter remained unchanged. Stroke index increased significantly after fentanyl, 50 μg/kg, and remained elevated at all subsequent intervals. Cardiac index increased after fentanyl, 50 μg/kg and 100 μg/kg. Rate-pressure product was stable until the time of sternotomy after which it decreased significantly. In patients undergoing aortocoronary bypass surgery, 100% oxygen, fentanyl, 100 μg/kg, and droperidol, 0.15 mg/kg, produced stable hemodynamics during induction, intubation, and sternotomy. Maintenance of pulmonary capillary wedge pressure by volume infusion may have contributed to this stability.

Problems of impedance cardiography

Various electrical-impedance methods have been proposed for the measurement of haemodynamic parameters noninvasively. For example, an impedance method is proposed for the measurement of cardiac output from the skin surface and is called impedance cardiography. However, there are many problems in the application of the impedance technique for the noninvasive measurement of haemodynamic parameters. One of them is the complicated structure of organs in the body. Another is the anomalous electrical properties of tissues. For these reasons, it is very difficult to obtain exact information about haemodynamics from the waveforms measured by the impedance cardiograph, in spite of the fact that the waveforms include much useful information. We can get useful information, if the relationships between the waveforms and the biomedical events in the subject are understood. In this paper, the relationships between the waveforms and the circulation of the blood are discussed theoretically and experimentally. The effects of the complicated structure of the organs and the anomalous electrical properties of tissues upon the waveforms are also discussed both theoretically and experimentally. For the analysis of the waveforms, it is very important to discuss (a) equipotential lines and potential distribution on the thorax, (b) the impedance or admittance between a pair of electrodes, (c) impedance or admittance changes due to blood circulation, (d) waveforms due to the pulsatile blood flow and (e) the effects of the complicated structure of organs upon the waveforms. From our results, it is concluded that: (a) the waveforms measured by an impedance cardiograph are affected not only by the change of blood volume in the aorta but also by that in various organs such as the heart and lungs. (b) the impedances measured by a pair of small electrodes separated by a short distance give useful information about the region in the vicinity of the electrodes (c) much valuable information will be available, if the relationships between the measurement results and the pulsatile blood flow are understood, and (d) by choosing an appropriate electrode arrangement, we may get much useful information about the blood circulation in the organs we want to investigate

Venous ultrasound catheter-tip technique for evaluation of arterial hemodynamics.

A variety of devices has been used for measuring flow properties of deep-lying arteries, but many have limitations. This paper describes a relatively nontraumatic intravenous approach which uses a catheter in connection with a pulsed ultrasonic Doppler velocity meter (PUDVM) and an ultrasound echo track. The venous ultrasound catheter (VUC) has permitted measurements of local instantaneols blood velocity, flow, and wall motion in the abdominal aorta and iliac arteries of beagle dogs; evaluation studies have been conducted to compare the VUC recordings with an independent method for measuring blood flow and wall motion. Coupling of this catheter-tip device with the PUDVM and echo track provides chronic measurements of hemodynamic parameters in these deep vessels which were virtually impossible to obtain previously. This technique may prove useful in monitoring vessel pathology longitudinally as well as in basic experimental situations requiring flow and arterial wall mechanical properties.