The effect of lung injury and excessive lung fluid, on impedance cardiac output measurements, in the critically ill

Critchley, L.A.H.; Calcroft, R. M.; Tan, Perpetua E.; Kew, J.; Critchley, J. A. J. H.

doi:10.1007/s001340051232

Cited by 43 publications

(25 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[74][75][76]. Variance in electric skin conductivity between the body and the electrodes including temperature and humidity [77,78], patient movement and lack of clinician attention to exact placement of sticker-electrodes and electric noise may contribute to inaccurate and variables measurements reading [77,79,80].…”

Section: Thoracic Electrical Bioimpedancementioning

confidence: 99%

Guiding Goal-Directed Therapy

Suehiro

Joosten

Alexander

2014

Curr Anesthesiol Rep

View full text Add to dashboard Cite

Several studies have demonstrated that perioperative hemodynamic optimization (or ''goal directed therapy'') using minimally invasive hemodynamic monitoring technologies has the ability to improve postoperative patients' outcome with lower complication rates, shorter hospital lengths of stay, and lower cost of surgery. This specific concept of goal-directed therapy (GDT) uses perioperative cardiac output monitoring and manipulation of physiologic parameters (dynamic parameters of fluid responsiveness) to guide intravenous fluids and inotropic therapy with the goal of ensuring adequate tissue perfusion. Recently, the evidence related to the implementation of GDT strategies has been considered strong enough to allow for the creation of national recommendations in the UK, in France, and by the European Society of Anaesthesiology. The aims of the programs are to apply best practices to high-risk surgical patients and requires the participation of all clinicians involved in patients' care. Considering the potential clinical and economic benefits of GDT protocols and the positive recommendations from influential scientific societies, more and more hospitals around the world have become interested in implementing hemodynamic optimization in their departments. This review provides the information about the evolution of hemodynamic monitoring from invasive to the more recent noninvasive devices, and how these devices can be used in the operating rooms through well-defined algorithms of GDT.

show abstract

Section: Thoracic Electrical Bioimpedancementioning

confidence: 99%

Guiding Goal-Directed Therapy

Suehiro

Joosten

Alexander

2014

Curr Anesthesiol Rep

View full text Add to dashboard Cite

show abstract

“…The technique uses an equation to calculate cardiac output [16,27] that is based on a number of assumptions and the input of several measurements of patient size. Errors in these measurements can lead to large discrepancies in the measurement of cardiac output [31], which are further affected when lung injury is present [32,33]. However, the technique is still regarded by many as a reliable trend monitor and has been shown to provide reliable shortterm measurements of changes in stroke volume and cardiac output [18,34,35].…”

Section: Discussionmentioning

confidence: 99%

Short-term postural reflexes in diabetic patients with autonomic dysfunction

et al. 2004

View full text Add to dashboard Cite

Aims/hypothesis. Assessment of autonomic dysfunction provides prognostic data in diabetic patients. Clinical tests are limited to heart rate variability and blood pressure measurements. We investigated whether a detailed analysis of postural reflexes of patients during short-term head-up tilting and standing erect (both for 3 min) would provide useful clinical data. Methods. We studied 14 control subjects and 56 patients with Type 2 diabetes, stratified into four matched groups: uncomplicated, micro-albuminuria, marco-albuminuria and autonomic neuropathy, who were tilted 55°three times and were standing erect. Non-invasive finger plethysmography blood pressure measurements, using the Portapres, and impedance cardiac output measurements, using the RheoCardioMonitor, were continuously recorded throughout the study. Wavelets of the response to tilting and standing were drawn. The wavelets for the three tilts were combined to improve definition. The degree of autonomic dysfunction was quantified by calculating the baroreflex sensitivity index from the heart-rate and bloodpressure variability data. Results. Baroreflex sensitivity data confirmed that autonomic dysfunction increased as diabetic complications worsened (p<0.001). Both standing and tilting resulted in an initial decrease in blood pressure followed by recovery, an increase in heart rate which was more pronounced with standing and a decrease in stroke volume. Characteristic and incremental changes in these responses were noted as the complications of diabetes worsened (p<0.001). These were a greater decrease in blood pressure with loss of the recovery phase, a reduced heart-rate response and paradoxically an increase in stroke volume. Conclusion/interpretation. Non-invasive blood-pressure and stroke-volume measurements recorded during short-term tilting and standing promises to be useful in assessing diabetic autonomic dysfunction. [Diabetologia (2004) 47:304-311]

show abstract

“…The underestimation of ICG SV and CO, reported in the presence of excess EVLW (YOUNG and McQUILLAN, 1993;RAAIJMAKERS et al, 1998), is caused by spuriously reduced values of dZ/dtmax (YAMAKOSHI et al, 1977). Underestimations axe attributed to bypassing, or shunting of AC, so that the ITBV (Pb = 140 _+ 40 ~cm) is circumvented in favour of the more highly conductive pathways of the plasma-like oedema fluid, herein designated as the impedance Ze (Ppi ...... = 60-70 ~~cm) (CRITCHLEY et al, 2000) (Fig. 1).…”

Section: O2mentioning

confidence: 94%

“…(m) Uncorrected, the magnitude of dZ/dtmax and thus ICGderived SV are inversely related to the magnitude of excess EVLW (CRITCHLEY et al, 2000;RAAIJMAKERS et al, 1998;YOUNG and McQUILLAN, 1993).…”

Section: Z2c-zczomentioning

confidence: 98%

Stroke volume equation for impedance cardiography

Bernstein

Lemmens

2005

Med. Biol. Eng. Comput.

140

109

View full text Add to dashboard Cite

The study's goal was to determine if cardiac output (CO), obtained by impedance cardiography (ICG), would be improved by a new equation N, implementing a square root transformation for dZ/dtmax/Z0, and a variable magnitude, mass-based volume conductor Vc. Pulmonary artery catheterisation was performed on 106 cardiac surgery patients pre-operatively. Post-operatively, thermodilution cardiac output (TDCO) was simultaneously compared with ICG CO. dZ/dtmax/Z0 and Z0 were obtained from a proprietary bioimpedance device. The impedance variables, in addition to left ventricular ejection time TLVE and patient height and weight, were input using four stroke volume (SV) equations: Kubicek (K), Sramek (S), Sramek-Bernstein (SB), and a new equation N. CO was calculated as SV x heart rate. Data are presented as mean +/- SD. One way repeated measures of ANOVA followed by the Tukey test were used for inter-group comparisons. Bland-Altman methods were used to assess bias, precision and limits of agreement. P< 0.05 was considered statistically significant. CO implementing N (6.06 +/- 1.48 l min(-1)) was not different from TDCO (5.97 +/- 1.41 l min(-1)). By contrast, CO calculated using K (3.70 +/- 1.53 l min(-1)), S (4.16 +/- 1.83 l min(-1)) and SB (4.37 +/- 1.82 l min(-1)) was significantly less than TDCO. Bland-Altman analysis showed poor agreement between TDCO and K, S and SB, but not between TDCO and N. Compared with TDCO, equation N, using a square-root transformation for dZ/dtmax/Z0, and a mass-based Vc, was superior to existing transthoracic impedance techniques for SV and CO determination.

show abstract

The effect of lung injury and excessive lung fluid, on impedance cardiac output measurements, in the critically ill

Abstract: The BoMed under-estimates cardiac output in critically ill patients. In septic patients the degree of attenuation of IC(co) can be related to the extent of lung injury and fluid accumulation within the thorax.

Cited by 43 publications

References 32 publications

Guiding Goal-Directed Therapy

Guiding Goal-Directed Therapy

Short-term postural reflexes in diabetic patients with autonomic dysfunction

Stroke volume equation for impedance cardiography

Contact Info

Product

Resources

About