51
|
Abstract
Early in the management of acute illness, it is critically important that volume status is accurately estimated. If inappropriate therapy is given because of errors in volume assessment, acute mortality rates are increased. Unfortunately, as the gold standard of radioisotopic volume measurement is costly and time-consuming, in the acute care environment clinicians are forced to rely on less accurate measures. In this manuscript, the authors review the currently available techniques of volume assessment for patients presenting with acute illness. In addition to discussing the accuracy of the history, physical examination, and radiography, acoustic cardiography and bedside ultrasonography are presented.
Collapse
Affiliation(s)
- W Frank Peacock
- Emergency Services Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | | |
Collapse
|
52
|
Tonelli AR, Alnuaimat H, Li N, Carrie R, Mubarak KK. Value of impedance cardiography in patients studied for pulmonary hypertension. Lung 2011; 189:369-75. [PMID: 21604215 DOI: 10.1007/s00408-011-9299-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 05/04/2011] [Indexed: 10/18/2022]
Abstract
The aim of this study was to evaluate the accuracy and precision of impedance cardiography as a method for noninvasive hemodynamic evaluation of patients with pulmonary hypertension (PH). We performed a prospective and blinded study of patients who underwent right heart catheterization (RHC) for evaluation of known or presumed PH at the University of Florida from August 2009 to March 2010. The cohort consisted of a total of 39 patients (age = 57 ± 14 years, 87% women) with presumed (23%) or confirmed PH (77%) of different etiologies. Patients underwent RHC and impedance cardiography using the PhysioFlow PF-05. The PhysioFlow PF-05 measures cardiac output (CO) and LV end-diastolic volume (LVEDV), among other parameters. The median pulmonary artery pressure was 36 (IQR 26-56) mmHg. The CO (mean ± SD) by thermodilution (CO-T) and by impedance cardiography (CO-IC) was 5.9 ± 2.2 and 5.6 ± 1.5 L/min, respectively. Bland-Altman analysis of CO-T versus CO-IC revealed a mean of 0.3 L/min (95% LoA: -2.2 to +2.8). In patients with PH, the correlation of CO-T and CO-IC had a mean of 0.4 L/min (95% LoA: 2.9 and -2.2). Pulmonary artery occlusion pressure (PAOP) correlated with LVEDV (R (2) = 0.2, p = 0.005). By ROC analysis, EDV ≥ 200 ml had a sensitivity of 53% and a specificity of 86% for PAOP > 15 mmHg (AUC = 0.78). In patients with PH, impedance cardiography had good accuracy and fair precision for CO determination when compared with thermodilution. Impedance cardiography may provide information about the preload status and has the potential to become a cost-effective and noninvasive method for the follow-up of patients with PH.
Collapse
Affiliation(s)
- Adriano R Tonelli
- Division of Pulmonary, Critical Care and Sleep Medicine, Cleveland Clinic, 9500 Euclid Avenue A-90, Cleveland, OH 44195, USA.
| | | | | | | | | |
Collapse
|
53
|
Mohammed I, Phillips C. Techniques for determining cardiac output in the intensive care unit. Crit Care Clin 2010; 26:355-64, table of contents. [PMID: 20381725 DOI: 10.1016/j.ccc.2010.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
To achieve the goals of resuscitation in critically ill patients, a thorough understanding of the techniques available to measure cardiac output is important. Recently the pulmonary artery catheter has fallen out of favor because of concerns of safety and a lack of efficacy. Newer less invasive techniques since have been developed and are gaining popularity. But is important to remember that the ability of these techniques to improve outcome has yet to be demonstrated, and one should apply caution in how they are used until their use in algorithmic treatment approaches have been shown to improve outcome. This article discusses the invasive and noninvasive techniques to assess cardiac output.
Collapse
Affiliation(s)
- Imran Mohammed
- Division of Pulmonary and Critical Care Medicine, Oregon Health and Science University, UHN-67, 3181 Southwest Sam Jackson Park Road, Portland, OR, USA
| | | |
Collapse
|
54
|
Napoli AM, Corl K, Gardiner F, Forcada A. Prognostic value of noninvasive measures of contractility in emergency department patients with severe sepsis and septic shock undergoing early goal-directed therapy. J Crit Care 2010; 26:47-53. [PMID: 20646897 DOI: 10.1016/j.jcrc.2010.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Revised: 03/23/2010] [Accepted: 05/02/2010] [Indexed: 11/29/2022]
Abstract
PURPOSE Reversible ventricular dysfunction is common in sepsis. Impedance cardiography allows for noninvasive measurement of contractility through time interval or amplitude-based measures. This study evaluates the prognostic capacity of these measures in patients with severe sepsis or septic shock in the emergency department. METHODS This is a prospective observational cohort study of 56 patients older than 18 years meeting criteria for early goal-directed therapy (lactate level >4 mmol/L or systolic blood pressure <90 mm Hg after 2-L isotonic sodium chloride solution). Continuous collections of contractility measures were performed, and patients were followed until discharge or in-hospital death. RESULTS A significant 57% reduction in the accelerated contractility index (ACI) in nonsurvivors (71 1/s(2) [41-102]) compared with survivors (123 1/s(2) [98-147]) existed. Only ACI predicted in-hospital mortality (area under the receiver operating characteristic curve = 0.70, P < .01). Accelerated contractility index did not correlate with amount of prior fluid administration, central venous pressure, number of cardiac risk factors, or troponin I value. An ACI of less than 40 1/s(2) is 95% (84-99) specific with a positive likelihood ratio of 8.8 for predicting in-hospital mortality. CONCLUSIONS A reduced ACI is associated with mortality in critically ill emergency department patients presenting with severe sepsis and septic shock meeting criteria for early goal-directed therapy. This association appears to be independent of clinical or laboratory predictors of cardiac dysfunction or preload.
Collapse
Affiliation(s)
- Anthony M Napoli
- Department of Emergency Medicine, Brown University Medical School, Providence, RI 02903, USA.
| | | | | | | |
Collapse
|
55
|
Summers RL, Ward KR, Witten T, Convertino VA, Ryan KL, Coleman TG, Hester RL. Validation of a computational platform for the analysis of the physiologic mechanisms of a human experimental model of hemorrhage. Resuscitation 2009; 80:1405-10. [PMID: 19804937 PMCID: PMC3042239 DOI: 10.1016/j.resuscitation.2009.09.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 09/01/2009] [Indexed: 11/24/2022]
Abstract
Computational models of integrative physiology may serve as a framework for understanding the complex adaptive responses essential for homeostasis in critical illness and resuscitation and may provide insights for design of diagnostics and therapeutics. In this study a computer model of human physiology was compared to results obtained from experiments using Lower Body Negative Pressure (LBNP) analog model of human hemorrhage. LBNP has been demonstrated to produce physiologic changes in humans consistent with hemorrhage. The computer model contains over 4000 parameters that describe the detailed integration of physiology based upon basic physical principles and established biologic interactions. The LBNP protocol consisted of a 5min rest period (0mmHg) followed by 5min of chamber decompression of the lower body to -15, -30, -45, and -60mmHg and additional increments of -10mmHg every 5min until the onset of hemodynamic decompensation (n=20). Physiologic parameters recorded include mean arterial pressure (MAP), cardiac output (CO), and venous oxygen saturation (SVO(2); from peripheral venous blood), during the last 30s at each LBNP level. The computer model analytic procedure recreates the investigational protocol for a virtual individual in an In Silico environment. After baseline normalization, the model predicted measurements for MAP, CO, and SVO(2) were compared to those observed through the entire range of LBNP. Differences were evaluated using standard statistical performance error measurements (median performance error (PE) <5%). The simulation results closely tracked the average changes observed during LBNP. The predicted MAP fell outside the standard error measurement for the experimental data at only LBNP -30mmHg while CO was more variable. The predicted SVO(2) fell outside the standard error measurement for the experimental data only during the post-LBNP recovery point. However, the statistical median PE measurement was found to be within the 5% objective error measure (1.3% for MAP, -3.5% for CO, and 3.95% for SVO(2)). The computer model was found to accurately predict the experimental results observed using LBNP. The model should be explored as a platform for studying concepts and physiologic mechanisms of hemorrhage including its diagnosis and treatment.
Collapse
Affiliation(s)
- Richard L Summers
- University of Mississippi Medical Center, Jackson, MS 39216, United States.
| | | | | | | | | | | | | |
Collapse
|
56
|
Milzman D, Napoli A, Hogan C, Zlidenny A, Janchar T. Thoracic impedance vs chest radiograph to diagnose acute pulmonary edema in the ED. Am J Emerg Med 2009; 27:770-5. [DOI: 10.1016/j.ajem.2008.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 05/30/2008] [Accepted: 06/07/2008] [Indexed: 10/20/2022] Open
|
57
|
Peacock WF, Fonarow GC, Ander DS, Collins SP, Gheorghiade M, Kirk JD, Filippatos G, Diercks DB, Trupp RJ, Hiestand B, Amsterdam EA, Abraham WT, Amsterdam EA, Dodge G, Gaieski DF, Gurney D, Hayes CO, Hollander JE, Holmes K, Januzzi JL, Levy P, Maisel A, Miller CD, Pang PS, Selby E, Storrow AB, Weintraub NL, Yancy CW, Bahr RD, Blomkalns AL, McCord J, Nowak RM, Stomel RJ. Society of Chest Pain Centers recommendations for the evaluation and management of the observation stay acute heart failure patient—part 1. ACTA ACUST UNITED AC 2009; 11:3-42. [DOI: 10.1080/02652040802688690] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
58
|
Funk DJ, Moretti EW, Gan TJ. Minimally invasive cardiac output monitoring in the perioperative setting. Anesth Analg 2009; 108:887-97. [PMID: 19224798 DOI: 10.1213/ane.0b013e31818ffd99] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
With advancing age and increased co-morbidities in patients, the need for monitoring devices during the perioperative period that allow clinicians to track physiologic variables, such as cardiac output (CO), fluid responsiveness and tissue perfusion, is increasing. Until recently, the only tool available to anesthesiologists to monitor CO was either a pulmonary artery catheter or transesophageal echocardiograph. These devices have their limitations and potential for morbidity. Several new devices (including esophageal Doppler monitors, pulse contour analysis, indicator dilution, thoracic bioimpedance and partial non-rebreathing systems) have recently been marketed which have the ability to monitor CO noninvasively and, in some cases, assess the patient's ability to respond to fluid challenges. In this review, we will describe these new devices including the technology, studies on their efficacy and the limitations of their use.
Collapse
Affiliation(s)
- Duane J Funk
- Department of Anesthesiology, Division of Critical Care, Duke University Medical Center, Durham, NC 27710, USA
| | | | | |
Collapse
|
59
|
Tang WHW, Tong W. Measuring impedance in congestive heart failure: current options and clinical applications. Am Heart J 2009; 157:402-11. [PMID: 19249408 PMCID: PMC3058607 DOI: 10.1016/j.ahj.2008.10.016] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 10/07/2008] [Indexed: 02/07/2023]
Abstract
Measurement of impedance is becoming increasingly available in the clinical setting as a tool for assessing hemodynamics and volume status in patients with heart failure. The 2 major categories of impedance assessment are the band electrode method and the implanted device lead method. The exact sources of the impedance signal are complex and can be influenced by physiologic effects such as blood volume, fluid, and positioning. This article provides a critical review of our current understanding and promises of impedance measurements, the techniques that have evolved, as well as the evidence and limitations regarding their clinical applications in the setting of heart failure management.
Collapse
Affiliation(s)
- W H Wilson Tang
- Heart and Vascular Institute, Cleveland Clinic, OH 44195, USA.
| | | |
Collapse
|
60
|
Summers HRL, Woodward LH, Thompson JR, Jackson-Williams L, Peacock WF. Impedance cardiographic waveform changes in response to treatment of acute heart failure: a case study. ACTA ACUST UNITED AC 2008; 14:157-60. [PMID: 18550927 DOI: 10.1111/j.1751-7133.2008.07616.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Heart Richard L Summers
- Department of Emergency Medicine, University of Mississippi Medical Center, Jackson, MS 39110, USA.
| | | | | | | | | |
Collapse
|
61
|
Affiliation(s)
- George C Velmahos
- John F. Burke Professor of Surgery, Harvard Medical School, Chief, Division of Trauma, Emergency Surgery, and Surgical Critical Care, Massachusetts General Hospital, Boston, Massachusetts, USA
| | | |
Collapse
|
62
|
Peacock WF, Fonarow GC, Ander DS, Maisel A, Hollander JE, Januzzi JL, Yancy CW, Collins SP, Gheorghiade M, Weintraub NL, Storrow AB, Pang PS, Abraham WT, Hiestand B, Kirk JD, Filippatos G, Gheorghiade M, Pang PS, Levy P, Amsterdam EA. Society of Chest Pain Centers Recommendations for the evaluation and management of the observation stay acute heart failure patient: a report from the Society of Chest Pain Centers Acute Heart Failure Committee. Crit Pathw Cardiol 2008; 7:83-86. [PMID: 18520521 DOI: 10.1097/01.hpc.0000317706.54479.a4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
|
63
|
Norozi K, Beck C, Osthaus WA, Wille I, Wessel A, Bertram H. Electrical velocimetry for measuring cardiac output in children with congenital heart disease. Br J Anaesth 2007; 100:88-94. [PMID: 18024954 DOI: 10.1093/bja/aem320] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The purpose of this study was to evaluate the agreement of cardiac output measurements obtained by electrical velocimetry (CO(EV)) and those that derived from the direct Fick-oxygen principle (CO(F)) in infants and children with congenital heart defects. METHODS Simultaneous measurements of CO(EV) and CO(F) were compared in 32 paediatric patients, aged 11 days to 17.8 yr, undergoing diagnostic right and left heart catheterization. For non-invasive measurements of cardiac output by electrical velocimetry, which is a variation of impedance cardiography, standard surface electrodes were applied to the left side of the neck and the left side of the thorax at the level of the xiphoid process. Cardiac output determined using direct Fick-oxygen principle was calculated by direct measurement of oxygen consumption (VO2) and invasive determination of the arterio-venous oxygen content difference. RESULTS An excellent correlation (r=0.97) was found between CO(EV) and CO(F) (P<0.001). The slope of the regression equation [0.96 (SD 0.04)] was not significantly different from the line of identity. The bias between the two methods (CO(EV)-CO(F)) was 0.01 litre min(-1) and the limits of agreement, defined as the bias (2 SD), were -0.47 and +0.45 litre min(-1). CONCLUSIONS CO(EV) demonstrates acceptable agreement with data derived from CO(F) in infants and children with congenital heart disease. The new technique is simple, completely non-invasive, and provides beat-to-beat estimation of CO.
Collapse
Affiliation(s)
- K Norozi
- Department of Pediatric Cardiology and Intensive Care Medicine, Medical School Hannover, OE 6730, Carl-Neuberg-Str. 1, 30623 Hannover, Germany.
| | | | | | | | | | | |
Collapse
|
64
|
Kitzler TM, Sergeyeva O, Morris A, Skrabal F, Kotanko P, Levin NW. Noninvasive Measurement of Cardiac Output in Hemodialysis Patients by Task Force Monitor: A Comparison with the Transonic System. ASAIO J 2007; 53:561-5. [PMID: 17885328 DOI: 10.1097/mat.0b013e31812e6a90] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysis (MHD) patients. The Transonic (TRS; Transonic Systems, Ithaca, NY) device is frequently used for determination of cardiac output (CO) by an indicator dilution technique. The Task Force Monitor (TFM; CN Systems, Graz, Austria) has gained attention as noninvasive tool for continuous beat-to-beat assessment of cardiovascular variables, including CO by impedance cardiography. Despite its use in cardiology and intensive care settings, the TFM has yet not been validated in dialysis patients. This study compares CO measurements in 12 MHD patients by TFM and TRS. Bland-Altman and regression analysis were used. CO was measured simultaneously by TRS and TFM. Average CO was 5.4 L/min by TRS and 5.0 L/min by TFM, respectively. Bland-Altman analysis revealed no significant systematic differences between the two methods (mean difference: 0.4 L/min; SD: 0.6; p > 0.05). Linear regression analysis showed significant correlation between both techniques (r = 0.802, p = 0.002). The SD of mean individual CO values was 1.1 L/min with TRS and 0.8 L/min with TFM, respectively.CO measured by TFM and TRS does not differ significantly, thus making the TFM an attractive noninvasive tool for the continuous beat-to-beat assessment of CO in MHD patients.
Collapse
|
65
|
Eldadah BA, Pechnik SL, Holmes CS, Moak JP, Saleem AM, Goldstein DS. Failure of propranolol to prevent tilt-evoked systemic vasodilatation, adrenaline release and neurocardiogenic syncope. Clin Sci (Lond) 2007; 111:209-16. [PMID: 16634720 DOI: 10.1042/cs20060017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In patients with neurocardiogenic syncope, head-up tilt often evokes acute loss of consciousness accompanied by vasodilatation, increased plasma adrenaline and systemic hypotension. Since hypotension increases adrenaline levels and adrenaline can produce skeletal muscle vasodilatation by activating beta2 receptors, adrenaline might induce a positive feedback loop precipitating circulatory collapse. We hypothesized that propranolol, a non-selective beta-blocker, would prevent adrenaline-induced vasodilatation and thereby prevent syncope. Eight subjects with recurrent neurocardiogenic syncope and previously documented tilt-induced syncope with elevated plasma adrenaline levels participated in the present study. Subjects underwent tilt table testing after receiving oral propranolol or placebo in a double-blind randomized crossover fashion. Haemodynamic and neurochemical variables were measured using intra-arterial monitoring, impedance cardiography, arterial blood sampling and tracer kinetics of simultaneously infused [3H]noradrenaline and [3H]adrenaline. The occurrence of tilt-induced neurally mediated hypotension and syncope, duration of tilt tolerance, extent of the decrease in SVRI (systemic vascular resistance index) and magnitude of plasma adrenaline increases did not differ between the propranolol and placebo treatment phases. SVRI was inversely associated with fractional increase in plasma adrenaline during both phases. One subject did not faint when on propranolol; this subject's response is discussed in the context of central effects of propranolol. In this small, but tightly controlled, study, propranolol did not prevent tilt-induced vasodilatation, syncope or elevated plasma adrenaline.
Collapse
Affiliation(s)
- Basil A Eldadah
- Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1620, USA.
| | | | | | | | | | | |
Collapse
|
66
|
Peacock WF, Summers RL, Vogel J, Emerman CE. Impact of impedance cardiography on diagnosis and therapy of emergent dyspnea: the ED-IMPACT trial. Acad Emerg Med 2006; 13:365-71. [PMID: 16531605 DOI: 10.1197/j.aem.2005.11.078] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Dyspnea is one of the most common emergency department (ED) symptoms, but early diagnosis and treatment are challenging because of multiple potential causes. Impedance cardiography (ICG) is a noninvasive method to measure hemodynamics that may assist in early ED decision making. OBJECTIVES To determine the rate of change in working diagnosis and initial treatment plan by adding ICG data during the course of ED clinical evaluation of elder patients presenting with dyspnea. METHODS The authors studied a convenience sample of dyspneic patients 65 years and older who were presenting to the EDs of two urban academic centers. The attending emergency physician was initially blinded to the ICG data, which was collected by research staff not involved in patient care. At initial ED presentation, after history and physical but before central lab or radiograph data were returned, the attending ED physician completed a case report form documenting diagnosis and treatment plan. The physician then was shown the ICG data and the same information was again recorded. Pre- and post-ICG differences were analyzed. RESULTS Eighty-nine patients were enrolled, with a mean age of 74.8 +/- 7.0 years; 52 (58%) were African American, 42 (47%) were male. Congestive heart failure and chronic obstructive pulmonary disease were the most common final diagnoses, occurring in 43 (48%), and 20 (22%), respectively. ICG data changed the working diagnosis in 12 (13%; 95% CI = 7% to 22%) and medications administered in 35 (39%; 95% CI = 29% to 50%). CONCLUSIONS Impedance cardiography data result in significant changes in ED physician diagnosis and therapeutic plan during the evaluation of dyspneic patients 65 years and older.
Collapse
Affiliation(s)
- W Frank Peacock
- Department of Emergency Medicine, Cleveland Clinic, Cleveland, OH, USA.
| | | | | | | |
Collapse
|
67
|
Schmidt C, Theilmeier G, Van Aken H, Korsmeier P, Wirtz SP, Berendes E, Hoffmeier A, Meissner A. Comparison of electrical velocimetry and transoesophageal Doppler echocardiography for measuring stroke volume and cardiac output † †Declaration of interest. This study was supported by Osypka Medical GmbH, Berlin, Germany. Br J Anaesth 2005; 95:603-10. [PMID: 16155037 DOI: 10.1093/bja/aei224] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Impedance cardiography (ICG) has been used extensively to estimate stroke volume (SV) and cardiac output (CO) from changes of thoracic electrical bioimpedance (TEB). However, studies comparing ICG with reference methods have questioned the reliability of this approach. Electrical velocimetry (EV) provides a new algorithm to calculate CO from variations in TEB. As the transoesophageal Doppler echocardiographic quantification of CO (TOE-CO) has emerged as a reliable method, the purpose of this study was to determine the limits of agreement between CO estimations using EV (EV-CO) and TOE-CO. METHODS Standard ECG electrodes were used for non-invasive EV-CO measurements. These were placed on 37 patients scheduled for coronary artery surgery necessitating transoesophageal echocardiography monitoring. Simultaneous EV-CO and TOE-CO measurements were recorded after induction of anaesthesia. EV-CO was calculated using the Bernstein-Osypka equation. TOE-CO was measured across the aortic valve using continuous-wave Doppler echocardiography and a triangular orifice model. RESULTS A significant high correlation was found between the TOE-CO and the EV-CO measurements (r2=0.86). Data were related linearly. The slope of the line (1.10 (se 0.07)) was not significantly different from unity, and the point at which it intersected the ordinate (-0.46 (0.32) litre min(-1)) was not significantly different from zero. Bland-Altman analysis revealed a bias of 0.18 litre min(-1) with narrow limits of agreement (-0.99 to 1.36 litre min(-1)). CONCLUSIONS The agreement between EV-CO and TOE-CO is clinically acceptable, and these two techniques can be used interchangeably.
Collapse
Affiliation(s)
- C Schmidt
- Department of Anaesthesiology and Surgical Intensive Care Medicine, University of Münster Hospital, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
68
|
Summers RL. Emerging diagnostics: impedance cardiography in the assessment and management of acute heart failure. Crit Pathw Cardiol 2005; 4:134-139. [PMID: 18340199 DOI: 10.1097/01.hpc.0000174911.92565.16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Richard L Summers
- Department of Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
| |
Collapse
|
69
|
Abstract
OBJECTIVES To examine the published evidence regarding the use of transthoracic electric bioimpedance (TEB) for the non-invasive monitoring of cardiac output in the ED. METHOD Databases of the medical literature, relevant textbooks and the Internet were searched for articles regarding TEB. Criteria for inclusion were drawn up prior to examination of the articles and included adherence to guidelines for comparing methods of clinical measurement. RESULTS Results are discussed under the following headings: technological capability, diagnostic accuracy, limitations, range of possible uses, therapeutic impact, impact on health care providers, patient outcome and future directions. CONCLUSION TEB is a technique for the non-invasive monitoring of cardiac output whose ease of use, continuous data acquisition and versatility suggest it may have a role to play in the care of patients in our EDs.
Collapse
Affiliation(s)
- Ogilvie Thom
- Department of Epidemiology and Preventive Medicine, Monash University, Box Hill Hospital, Victoria, Australia.
| | | |
Collapse
|
70
|
Abstract
The delivery of critical care is no longer limited to the intensive care unit. The information gained by utilization of new technologies has proven beneficial in some populations. Research into earlier and more widespread use of these modalities may prove to be of even greater benefit to critically ill patients.
Collapse
Affiliation(s)
- Ronny Otero
- Department of Emergency Medicine, Henry Ford Hospital, Detroit, Michigan, USA.
| | | |
Collapse
|
71
|
Albert NM, Hail MD, Li J, Young JB. Equivalence of the Bioimpedance and Thermodilution Methods in Measuring Cardiac Output in Hospitalized Patients With Advanced, Decompensated Chronic Heart Failure. Am J Crit Care 2004. [DOI: 10.4037/ajcc2004.13.6.469] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
• Background An accurate and reliable noninvasive method for determining cardiac output/cardiac index would be valuable for patients with acutely decompensated advanced systolic heart failure.• Objectives To determine whether a correlation exists for cardiac output and index determined by using bioimpedance and thermodilution in patients with acutely decompensated complex heart failure and if differences between results with the 2 methods could be explained by the patients’ advanced condition.• Methods Cardiac output and index were determined by using bioimpedance and thermodilution in 33 patients. Echocardiographic and electrocardiographic data were assessed to determine if differences between results with the 2 methods could be explained by the patients’ advanced condition. Concordance correlation coefficients and Bland-Altman agreement between methods were calculated.• Results Four patients were excluded from analysis because reliable measurements could not be obtained; the remaining 29 patients constituted the study population. Mean cardiac outputs determined by thermodilution and bioimpedance were 5.48 and 5.40 L/min, respectively (ρc =0.89, P < .001), and mean cardiac indexes were 2.67 and 2.65 (ρc = 0.82, P < .001). Mean bias (limits of agreement) between data pairs was 0.08 (−0.18 to 0.35) L/min (P = .52) for cardiac output and 0.03 (−0.097 to 0.16; P = .61) for cardiac index. Six data pairs (21%) had an absolute percent difference greater than 15%. Of these, 50% had a higher thermodilution value.• Conclusion Determinations of cardiac output and index by both methods were significantly correlated. Mean bias between the 2 methods was small, suggesting clinical utility for bioimpedance in patients with complex decompensated heart failure.
Collapse
Affiliation(s)
- Nancy M. Albert
- The Division of Nursing (NMA), George M. and Linda H. Kaufman Center for Heart Failure (MDH), Department of Biostatistics and Epidemiology (JL), and the Department of Cardiovascular Medicine (JBY), Cleveland Clinic Foundation, Cleveland, Ohio
| | - Melanie D. Hail
- The Division of Nursing (NMA), George M. and Linda H. Kaufman Center for Heart Failure (MDH), Department of Biostatistics and Epidemiology (JL), and the Department of Cardiovascular Medicine (JBY), Cleveland Clinic Foundation, Cleveland, Ohio
| | - Jianbo Li
- The Division of Nursing (NMA), George M. and Linda H. Kaufman Center for Heart Failure (MDH), Department of Biostatistics and Epidemiology (JL), and the Department of Cardiovascular Medicine (JBY), Cleveland Clinic Foundation, Cleveland, Ohio
| | - James B. Young
- The Division of Nursing (NMA), George M. and Linda H. Kaufman Center for Heart Failure (MDH), Department of Biostatistics and Epidemiology (JL), and the Department of Cardiovascular Medicine (JBY), Cleveland Clinic Foundation, Cleveland, Ohio
| |
Collapse
|
72
|
Affiliation(s)
- Nancy M Albert
- Kaufman Center for Heart Failure, Cleveland Clinic Foundation, Oh., USA
| |
Collapse
|
73
|
Summers RL, Parrott CW, Quale C, Lewis DL. Use of noninvasive hemodynamics to aid decision making in the initiation and titration of neurohormonal agents. ACTA ACUST UNITED AC 2004; 10:28-31. [PMID: 15073483 DOI: 10.1111/j.1527-5299.2004.03552.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Angiotensin-converting enzyme inhibitors, beta adrenergic blockers, and nesiritide are pharmacologic agents for heart failure with both short- and long-term neurohormonal and hemodynamic effects. Angiotensin-converting enzyme inhibitors and beta adrenergic blockers reduce morbidity and mortality in chronic heart failure. Higher doses may result in better outcomes than lower doses, but concern about hemodynamic tolerance is a major barrier to the initiation and up-titration of these agents. Nesiritide is a newer neurohormonal agent with proven efficacy and safety for use in decompensated heart failure, but appropriate patient selection has been challenging for clinicians. Like vasodilators, nesiritide may be underutilized in heart failure treatment. Impedance cardiography is a newer, noninvasive monitoring technology that can accurately measure hemodynamic parameters. Impedance cardiography is being used with increasing frequency by clinicians to guide therapy in patients with heart failure and has been proposed in heart failure treatment algorithms. Three case reports are presented to illustrate how hemodynamic data using impedance cardiography can be utilized in the initiation and titration of neurohormonal agents.
Collapse
Affiliation(s)
- Richard L Summers
- Department of Emergency Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA.
| | | | | | | |
Collapse
|