Hemodynamic Monitoring Tool Research Articles

ECHOCARDIOGRAPHY FOR HEMODYNAMIC EVALUATION IN THE INTENSIVE CARE UNIT

The use of echocardiography in the intensive care unit for patients in shock allows the accurate measurement of several hemodynamic variables in a noninvasive way. By using echocardiography as a hemodynamic monitoring tool, the clinician can evaluate several aspects of shock states, such as cardiac output and fluid responsiveness, myocardial contractility, intracavitary pressures, and biventricular interactions. However, to date, there have been few guidelines suggesting an objective hemodynamic-based examination in the intensive care unit, and most intensivists are usually not familiar with this tool. In this review, we describe some of the most important hemodynamic parameters that can be obtained at the bedside with transthoracic echocardiography.

The Effects of Acute Salt Loading on Hemodynamic Parameters in Young Caucasian Males

Impedance cardiography (ICG) is a useful tool for non-invasive hemodynamic monitoring in clinical populations. However, the acute effects of salt (NaCl) loading have not been extensively studied in healthy young men. PURPOSE: The purpose of the current investigation was to determine the effects of non-dietary NaCl loading on hemodynamic parameters in Caucasian males using ICG. METHODS: Twenty four apparently healthy, young (23.6 ±2 yr) Caucasian males volunteered to participate in the current investigation. Subjects underwent two experimental trials consisting of a 30 minute baseline period, a 60 minute ingestion period (SALT vs. WATER), followed by a 120 minute recovery period. During the SALT trial, subjects ingested 11.3g of NaCl as well as 1136.5 ml of water; during the WATER trial, subjects only ingested water. Mean arterial pressure (MAP), cardiac index (CI), and systemic vascular resistance index (SVRI) were recorded every 10 minutes throughout the trials. All measurements were made in the seated position and urine output was quantified at the end of each trial. RESULTS: Data were analyzed using a 2 trial by 22 time point Analysis of Variance (ANOVA). Significant main effects and trial by time interactions were further explored with post hoc t-tests. The ANOVA revealed a main effect for time for changes in CI and increases in MAP and SVRI (p<0.001). A main effect for trial was observed for CI with values higher in the salt trial (p<0.001). Trial by time interactions were observed for CI and MAP (p<0.001). CI values increased during ingestion in the SALT trial while decreasing in the water trial. MAP values increased more so in the SALT vs. WATER trial during ingestion and into recovery. SVRI increased similarly in both trials. CONCLUSIONS: NaCl loading caused CI to increase during ingestion, relative to WATER, which increased MAP. This NaCl challenge appears to alter hemodynamics in this subclinical population of healthy young men. Further research could examine the effects of NaCl on other body systems.

The pulmonary artery catheter: In medio virtus

To clarify the role of the pulmonary artery catheter in the intensive care unit. Recent and relevant literature from MEDLINE and authors' personal databases. Studies on pulmonary artery catheter use and use of other monitoring devices in critically ill patients. Based largely on clinical experience and assessment of the relevant published literature and in response to recent articles attacking the pulmonary artery catheter, we propose that the pulmonary artery catheter is still a valuable tool for the hemodynamic monitoring of patients with complex disease processes in whom the information obtained from the pulmonary artery catheter may influence management. We suggest that there is a need to revisit the basics of hemodynamic management and reassess the way in which the pulmonary artery catheter is used, applying three key principles: correct measurement, correct data interpretation, and correct application. The pulmonary artery catheter is still a valuable tool for hemodynamic monitoring when used in selected patients and by physicians adequately trained to correctly interpret and apply the data provided.

Non-invasive determination of stroke volume and cardiac output after high intensity playing exercise in elite female soccer players

Background Stroke volume (SV) and heart rate (HR), determining cardiac output (CO), are crucial hemodynamic parameters determining training adoptions to endurance training. In soccer, aerobic power as well as intermittent exercise performance varies significantly among level of competition as well as playing position. In this study cohort study we thought to determine the hemodynamic changes following a standardized soccer-specific exercise in female soccer players at the soccer field using a portable non-invasive hemodynamic monitoring tool. Methods A non-invasive, portable continuous wave (CW) Doppler-based ultrasound system (USCOM, Sydney, Australia) was used to assess HR, SV, CO, and cardiac index (CI) using a suprasternal approach after a soccer specific exercise (5-vs-2-gameplay over 5 min) in an elite female soccer team of the German Fussball Bundesliga (15 females, 22.3 ± 3.6 years). Results 30 s after the peak exercise the mean HR increased significantly (121 ± 26 /min vs 56 ± 11 /min, p < 0.05), while SV did not change significantly (75 ± 25 ml vs. 80 ± 13 ml, n.s.). CO increased significantly (9.2 ± 4.1 l/min vs. 4.5 ± 1.1 l/min) as did CI (5.3 ± 2.1 l/min/m 2 vs. 2.6 ± 0.6 l/min/m 2, p < 0.05). Conclusion Elite female soccer players increase cardiac output after 5-vs-2-gameplay on average to 10 l/min, in single cases up to 18 l/min 30 s after peak exercise. Therefore significant peak hemodynamic demands are encountered in soccer game play. The increase of cardiac output is by far more achieved by an increase of the heart rate than by stroke volume changes in most of the female soccer players. On field hemodynamic exercise testing is feasible using the USCOM in elite soccer.

The beneficial effects of angiotensin receptor blockers and angiotensin converting enzyme inhibitors on atrial electrical remodeling in patients with essential hypertension

Background: Stroke volume (SV) and heart rate (HR), determining cardiac output (CO), are crucial hemodynamic parameters determining training adoptions to endurance training. In soccer, aerobic power as well as intermittent exercise performance varies significantly among level of competition as well as playing position. In this study cohort study we thought to determine the hemodynamic changes following a standardized soccer-specific exercise in female soccer players at the soccer field using a portable non-invasive hemodynamic monitoring tool. Methods: A non-invasive, portable continuous wave (CW) Doppler-based ultrasound system (USCOM, Sydney, Australia) was used to assess HR, SV, CO, and cardiac index (CI) using a suprasternal approach after a soccer specific exercise (5-vs-2-gameplay over 5 min) in an elite female soccer team of the German Fussball Bundesliga (15 females, 22.3±3.6 years). Results: 30 s after the peak exercise the mean HR increased significantly (121±26 /min vs 56±11 /min, pb0.05), while SV did not change significantly (75±25 ml vs. 80±13 ml, n.s.). CO increased significantly (9.2±4.1 l/min vs. 4.5±1.1 l/min) as did CI (5.3±2.1 l/min/m vs. 2.6±0.6 l/min/m, pb0.05). Conclusion: Elite female soccer players increase cardiac output after 5-vs-2-gameplay on average to 10 l/min, in single cases up to 18 l/min 30 s after peak exercise. Therefore significant peak hemodynamic demands are encountered in soccer game play. The increase of cardiac output is by far more achieved by an increase of the heart rate than by stroke volume changes in most of the female soccer players. On field hemodynamic exercise testing is feasible using the USCOM in elite soccer. © 2007 Elsevier Ireland Ltd. All rights reserved.

Inter-Rater Agreement of a Non-Invasive Ultrasound Cardiac Output Monitoring (USCOM) Device in Emergency Department Patients

Objectives: The ultrasound cardiac output monitor (USCOM, USCOM Pty Ltd, Australia) has been shown to be a potential non-invasive alternative to the pulmonary artery catheter as a hemodynamic monitoring tool. The purpose of this study is to investigate the inter-rater agreement of the USCOM monitor when used in emergency department (ED) patients.

Cardiovascular monitoring tools: use and misuse.

To review important areas of current and novel hemodynamic monitoring practice in the intensive care unit and to highlight potential areas of physiologic and clinical use or misuse, as well as areas of uncertainty and ongoing controversy. To truly determine when hemodynamic monitoring tools are misused would require randomized controlled evidence of a measurable improvement in relevant clinical (as opposed to physiologic) outcomes. Unfortunately, little evidence of this kind exists, and that which does exist is highly controversial in nature. Because of the limited evidence of an effect of hemodynamic monitoring on clinical outcomes, the use and misuse of hemodynamic monitoring tools is typically judged on physiologic grounds (Does it improve physiology? Does it predict physiology? Is it physiologically rational?). The relation between physiologic gain and final clinical outcome, however, is tenuous. Recent investigations confirm this lack of a clear link. They also suggest that new technology that is now emerging to less invasively measure cardiac output and intrathoracic fluid compartments is ready for formal evaluations of efficacy and effectiveness. The effectiveness of hemodynamic monitoring in the intensive care unit remains inadequately tested and unproven. New tools are now rapidly emerging to challenge established technologies. Formal assessment of their efficacy and effectiveness is needed to avoid a repeat of the pulmonary artery catheter experience.

The effect of halothane on the amplitude and frequency characteristics of heart sounds in children.

Although continuous auscultation has been used during surgery as a monitor of cardiac function for many years, the effect of anesthetics on heart sounds has never been quantified. We determined the root mean squared amplitude and frequency characteristics (peak frequency, spectral edge, and power ratios) of the first (S1) and second (S2) heart sounds in 19 healthy children during induction of anesthesia with halothane. In all patients, halothane decreased the amplitude of S1 (R2 = 0.87 +/- 0.12) and S2 (R2 = 0.66 +/- 0.33) and the high-frequency components (>80 Hz) of these sounds. These changes were clearly audible and preceded decreases in heart rate and blood pressure. The spectral edge decreased for S1 in 18 patients (R2 = 0.73 +/- 0.24) and for S2 in 13 patients (R2 = 0.58 +/- 0.25). Peak frequency did not change. The rapidity with which myocardial depression and its associated changes in heart sound characteristics occurred confirms that continuous auscultation of heart sounds is a useful clinical tool for hemodynamic monitoring of anesthetized infants and children. Heart sound characteristics can be used to monitor cardiac function during halothane anesthesia in children. The changes occur rapidly and precede noticeable changes in heart rate and blood pressure.

Electrical Impedance Tomography

t. This paper surveys some of the work our group has done in electrical impedance tomography.

Fick-Derived Hemodynamics: Oxygen Consumption Measured Directly vs Oxygen Consumption Calculated from CO2 Production under Steady State and Dynamic Conditions

Indirect calorimetry is being used increasingly as a tool for hemodynamic monitoring via the Fick equation. This investigation was undertaken to examine the use of carbon dioxide elimination (VCO2A) and related respiratory quotient (RQA) to calculate oxygen uptake (VO2A) and estimate oxygen consumption (VO2) during steady-state and dynamic hemodynamic conditions. Nine patients undergoing abdominal aortic surgery were studied intraoperatively and Fick-derived hemodynamic measurements were made using a monitoring system employing indirect calorimetry, pulse oximetry, and pulmonary artery oximetry. Comparisons were made between measured VO2A and calculated VO2A derived from the VCO2A and the initial RQA (RQi), which is assumed not to change. Prior to aortic crossclamping (steady state), there were no significant differences between the measured and calculated methods with respect to oxygen consumption (184 +/- 24 ml/min vs 185 +/- 17 ml/min), oxygen delivery (753 +/- 141 ml/min vs 769 +/- 178 ml/min), and cardiac output (4.7 +/- 0.6 L/min vs 4.7 +/- 0.7 L/min). However, immediately following aortic unclamping (dynamic state), the RQA changed precipitously from the baseline RQi. Consequently, significant differences between the measured and calculated methods were noted in oxygen uptake (213 +/- 41 ml/min vs 193 +/- 25 ml/min, p < 0.001), oxygen delivery (780 +/- 297 ml/min vs 716 +/- 296 ml/min, p < 0.001), and cardiac output (5.8 +/- 2.2 L/min vs 5.3 +/- 1.8 L/min, p < 0.001). Additionally, following unclamping, the peak VO2A was 242 +/- 49 compared with a cVO2A of only 198 +/- 22 (p < 0.01). We conclude that the use of VCO2A to calculate VO2A may lead to erroneous measurements under dynamic conditions, such as unclamping of the abdominal aorta.