Bioimpedance cardiography measurements of cardiac output and other cardiovascular parameters.

This paper describes impedance technique and device types, discusses hemodynamic data parameters that are available, discusses the differences between impedance cardiography and data that are derived from invasive pulmonary artery catheters, and explains how nurses can apply bioimpedance cardiography in a variety of patient populations.

Using impedance cardiography to assess left ventricular systolic function via postural change in patients with heart failure.

For the diagnosis and management of heart failure, it would be useful to have a simple point-of-care test for assessing ventricular function that could be performed by a nurse. An impedance cardiography (ICG) parameter called systolic amplitude (SA) can serve as an indicator of left ventricular systolic function (LVSF). This study tested the hypothesis that patients with normal LVSF should have a significant increase in SA in response to an increase in end-diastolic volume caused by postural change from sitting upright to supine, while patients with depressed LVSF associated with heart failure should have a minimal increase or a decrease in SA from upright to supine. ICG data were obtained in 12 patients without heart disease and with normal LVSF and 18 patients with clinically diagnosed heart failure. Consistent with the hypothesis, patients with normal LVSF had a significant increase in SA from upright to supine, whereas heart failure patients had a minimal increase or a decrease in SA from upright to supine. This ICG procedure may be useful for monitoring the trend of patient response to titration of beta blockers and other medications. ICG potentially could be used to detect worsening LVSF and provide a means of measurement for adjusting treatment.

Non-invasive cardiac output monitoring.

Outcomes in the management of critically ill patients may be improved using goal-directed peri-operative haemodynamic monitoring. A conservative approach may no longer be acceptable but in view of the significant morbidity associated with balloon tipped flow directed pulmonary artery catheters a non-invasive approach would be preferable. In this review we consider the different non-invasive techniques available and discuss the advantages and disadvantages of each technique.

Outpatient cardiovascular management utilizing impedance cardiography.

Over the past decade, noninvasive hemodynamic and thoracic fluid status monitoring via impedance cardiography has provided clinicians practicing in the outpatient setting with a valuable tool for managing a myriad of cardiovascular disorders. This article reviews impedance cardiography technology and the use of impedance cardiography in the home and outpatient clinic settings for the assessment and management of heart failure, resistant hypertension, and dual-chamber pacemaker optimization.

Plethysmography: the new wave in haemodynamic monitoring--a review of clinical applications.

The plethysmograph, a useful, non-invasive circulatory assessment capability featured on most modern pulse oximeters, provides a waveform representation of pulsatile peripheral blood flow, from which can be drawn assessments of both the peripheral and central circulation. Implementation and maintenance of plethysmography monitoring is straightforward and uncomplicated by virtue of its non-invasiveness. Yet despite its capabilities, ease of use and widespread availability it remains an underutilised data source. Diagnostic and monitoring capabilities of the device include heart rate and rhythm monitoring, detection of myocardial and valvular dysfunction, assessment of intra-aortic balloon pump performance when pressure waveforms are unobtainable, detection and measurement of pulsus paradoxus, improved performance of the Allen's test and detection of peripheral vascular diseases, peripheral vasoconstriction and developing shock. This paper describes the range of established applications of plethysmography, reviews pertinent literature and describes the directions in which, in the absence of supportive literature, clinical practice is finding applications.

Advances in continuous, noninvasive hemodynamic surveillance. Impedance cardiography.

In the current climate of shrinking health care reimbursement and increasing importance of patient centered care, impedance cardiography is one method of enhancing quality of patient care and appropriate use of resources. Hemodynamic and thoracic fluid status data may be obtained quickly, accurately, and without risk, providing a global clinical perspective. Patients benefit from the ability to immediately obtain real time hemodynamic data, particularly those patients who otherwise may not be afforded a high level of monitoring or those needing hemodynamic monitoring when assessment and treatment are delayed because of inaccessibility of critical care beds or in the cardiac catheterization laboratory. Application of a technology assessment model to impedance cardiography illustrates the utility of this method of hemodynamic monitoring. Careful review and critique of the literature differentiates the available impedance technologies, supports use in areas not traditionally associated with hemodynamic monitoring, such as the home and emergency department, and validates the use of impedance cardiography in place of, or as an indication for, pulmonary artery catheterization.

The view within: the emerging technology of thoracic electrical bioimpedance.

With the increasing incidence of catheter-related sepsis and recognition of increased mortality and cost of care with pulmonary artery catheters, the need for a safe, cost-effective, and clinically accurate means of obtaining hemodynamic data has become evident. Through the technology of thoracic electrical bioimpedance (TEB), non-invasive hemodynamic monitoring is now possible with the BioZ.com, manufactured by CardioDynamics International Corporation. The BioZ.com provides continuous hemodynamic readings safely, accurately, and inexpensively. TEB is proving to be a valuable adjunct to patient assessment and treatment across multiple health care settings.

Noninvasive hemodynamic monitoring with thoracic electrical bioimpedance.

TEB is proving to be an exciting hemodynamic monitoring technique. It has been shown to accurately measure trends in the patient's volume and vasoactive state without the risks and discomfort of invasive monitoring. It can be applied easily and does not require specialized skill of nurses or physicians. A broad range of patient information can be displayed. However, continued education and implementation are important in helping nurses become adept at analyzing parameters that have not been measured with traditional monitoring. Further research is required to explore its possibilities and to determine which patients will benefit most from this form of monitoring.