Endotracheal Cardiac Output Monitor Research Articles

Comparing the Mutual Interchangeability of ECOM, FloTrac/Vigileo, 3D-TEE, and ITD-PAC Cardiac Output Measuring Systems in Coronary Artery Bypass Grafting

The aim of this study was to compare the mutual interchangeability of 4 cardiac output measuring devices by comparing their accuracy, precision, and trending ability. A single-center prospective observational study. Nonuniversity teaching hospital, single center. Forty-four consecutive patients scheduled for elective, nonemergent coronary artery bypass grafting (CABG). The cardiac output was measured for each participant using 4 methods: intermittent thermodilution via pulmonary artery catheter (ITD-PAC), Endotracheal Cardiac Output Monitor (ECOM), FloTrac/Vigileo System (FLOTRAC), and 3-dimensional transesophageal echocardiography (3D-TEE). Measurements were performed simultaneously at 5 time points: presternotomy, poststernotomy, before cardiopulmonary bypass, after cardiopulmonary bypass, and after sternal closure. A series of statistical and comparison analyses including ANOVA, Pearson correlation, Bland-Altman plots, quadrant plots, and polar plots were performed, and inherent precision for each method and percent errors for mutual interchangeability were calculated. For the 6 two-by-two comparisons of the methods, the Pearson correlation coefficients (r), the percentage errors (% error), and concordance ratios (CR) were as follows: ECOM_versus_ITD-PAC (r = 0.611, % error = 53%, CR = 75%); FLOTRAC_versus_ITD-PAC (r = 0.676, % error = 49%, CR = 77%); 3D-TEE versus ITD-PAC (r = 0.538, % error = 64%, CR = 67%); FLOTRAC_versus_ECOM (r = 0.627, % error = 51%, CR = 75%); 3D-TEE_versus ECOM (r = 0.423, % error = 70%, CR = 60%), and 3D-TEE_versus_FLOTRAC (r = 0.602, % error = 59%, CR = 61%). Based on the recommended statistical measures of interchangeability, ECOM, FLOTRAC, and 3D-TEE are not interchangeable with each other or to the reference standard invasive ITD-PAC method in patients undergoing nonemergent cardiac bypass surgery. Despite the negative result in this study and the majority of previous studies, these less-invasive methods of CO have continued to be used in the hemodynamic management of patients. Each device has its own distinct technical features and inherent limitations; it is clear that no single device can be used universally for all patients. Therefore, different methods or devices should be chosen based on individual patient conditions, including the degree of invasiveness, measurement performance, and the ability to provide real-time, continuous CO readings.

Endotracheal bioimpedance cardiography improves immediate postoperative outcome: a case-control study in off-pump coronary surgery

The feasibility and clinical utility of the endotracheal cardiac output monitor (ECOM) to optimize intraoperative hemodynamics and improve short-term outcome in off-pump coronary artery bypass grafting (OPCAB) is unknown. We aimed to compare ECOM with a standard of care in that specific surgical setting. Twenty consecutive adult ECOM-monitored patients undergoing OPCAB were prospectively included (ECOM group) and retrospectively compared to 42 patients scheduled for similar surgery without ECOM monitoring (Control group). The primary endpoint was the global rate of postoperative admission to the intensive care unit (ICU). Secondary endpoints were the time to extubation, the length of stay in ICU and in hospital, the postoperative levels of lactate and troponin and the feasibility of ECOM. The rate of postoperative admission to the ICU was 38/42 (90%) in the Control group versus 11/20 (55%) in the ECOM group, P = 0.008. None unexpected admission for hemodynamic instability was observed in the ECOM group. The time to extubation, the length of stay in ICU, and both troponin level at admission and lactate level at H6 were all significantly decreased in the ECOM group. On a scale ranging from 0 to 5, convenience and satisfaction regarding ECOM were 4.30 ± 1.17 and 3.45 ± 0.68, respectively. The systematic use of ECOM is associated with a significant reduction in the rate of admission to the ICU and an improvement in immediate outcome in OPCAB.

Early goal-directed therapy based on endotracheal bioimpedance cardiography: a prospective, randomized controlled study in coronary surgery.

The objective was to compare the impact of an early goal-directed hemodynamic therapy based on cardiac output monitoring (Endotracheal Cardiac Output Monitor, ECOM) with a standard of care on postoperative outcome following coronary surgery. This prospective, controlled, parallel-arm trial randomized 100 elective primary coronary artery bypass grafting patients to a study group (ECOM; n = 50) or a control group (control; n = 50). In the ECOM group, hemodynamic therapy was guided by respiratory stroke volume variation and cardiac index given by the ECOM system. A standard of care was used in the control. Goal-directed therapy was started immediately after induction of anesthesia and continued until arrival in the intensive care unit (ICU). The primary endpoint was the time when patients fulfilled discharge criteria from hospital (possible hospital discharge). Secondary endpoints were the hospital discharge, the time to reach extubation, the length of stay in ICU, the number of major adverse cardiac events, and in-hospital mortality. Patients in the ECOM group received more often fluid loading and dobutamine. The time to reach extubation was reduced in the ECOM group: 510 min [360-1,110] versus 570 min [320-1,520], P = 0.005. No significant differences were found between both groups for possible hospital discharge [Hazard Ratio = 0.96 (95 % CI 0.64-1.45)] and hospital discharge [Hazard Ratio = 1.20 (95 % CI 0.79-1.81)]. A mini-invasive early goal-directed hemodynamic therapy based on ECOM can reduce the time to reach extubation but fails to significantly reduce the length of stay in hospital and the rate of major cardiac morbidity.

Prediction of Effective Post-Operative Epidural Anesthesia Using Hemodynamic Changes Detected by Endotracheal Cardiac Output Monitor (ECOM)

Background: Epidural anesthesia after abdominal surgery results in improved postoperative pain relief but has up to a 30% failure rate. Hemodynamic changes after epidural administration of local anesthetics may provide parameters to predict dermatomal blockade and effective pain control in the postoperative period. The Endotracheal Cardiac Output Monitor (ECOM) provides continuous measurements of stroke volume (SV), cardiac output (CO) cardiac index (CI) and systemic vascular resistance (SVR). We hypothesized that the changes in hemodynamic parameters measured by the ECOM monitor along with changes in systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) would predict effective epidural anesthesia. Methods: 19 patients undergoing intra-abdominal surgery were enrolled. After placement of an epidural catheter and establishment of general anesthesia hemodynamics were recorded in 15-minute intervals using the ECOM monitor. At the start of abdominal closure epidural catheters were loaded with two 5 ml boluses of 0.25% bupivacaine in ten-minute intervals. Hemodynamic parameters where then recorded at five-minute intervals until conclusion of surgery. The number of dermatomes blocked, post anesthesia care unit (PACU) pain scores, average 24-hour pain scores, and patient satisfaction were recorded.Results: Significant reduction was observed in SBP, DBP, MAP and in SVR, and increases were seen in CO and CI after starting epidural anesthesia. From the parameters measured, only a significant reduction of SVR accompanied with higher level of dermatomes blocked, and lower average 24-hour pain scores. At the sane time patients without significant SVR change had relatively low pain scores, high patient satisfaction and required the same amount of pain medications. Conclusion: Changes in SVR detected by the ECOM monitor might help to predict an effective epidural system but its clinical relevance needs to be further evaluated.

Lack of agreement and trending ability of the endotracheal cardiac output monitor compared with thermodilution

Minimally invasive monitoring systems of central haemodynamics are gaining increasing popularity. The present study investigated the precision of the endotracheal cardiac output monitor (ECOM) system and its agreement with pulmonary artery catheter thermodilution (PAC TD) for measuring cardiac output (CO) during steady state and with induced haemodynamic changes in patients scheduled for elective cardiac surgery. Twenty-five patients were enrolled. After induction of anaesthesia, endotracheal intubation using a dedicated ECOM tube, and insertion of the pulmonary artery catheter (PAC), the patient was placed in the following successive positions: (a) supine, (b) head-down tilt, (c) head-up tilt, (d) supine, (e) supine with phenylephrine administration. CO was measured simultaneously using the ECOM and the PAC. Both methods showed an equally good precision < 10%. Compared to PAC TD, the ECOM system was associated with a bias in supine position of -0.45 l/min (95% confidence interval: -0.86; -0.05), limits of agreement -2.40 l/min to 1.49 l/min and a percentage error of 41.0%. There was no agreement in trending ability between the two methods, with a concordance rate of 30%, shown in a four-quadrant plot. In a direct comparison with PAC TD, the ECOM system did not show an acceptable agreement, with wide limits of agreement, a much larger percentage error than should be expected from the precision of the two methods and a very poor trending ability. Thus, the ECOM does not replace measurements done by thermodilution using a pulmonary artery catheter in cardiac surgery patients.

A Comparison of Endotracheal Bioimpedance Cardiography and Transpulmonary Thermodilution in Cardiac Surgery Patients

The authors hypothesized that bioimpedance cardiography measured by the Endotracheal Cardiac Output Monitor (ECOM; ConMed, Utica, NY) is a convenient and reliable method for both cardiac index (CI) assessment and prediction in fluid responsiveness. A prospective observational study. A teaching university hospital. Twenty-five adult patients. Admission to the intensive care unit after conventional cardiac surgery and investigation before and after a fluid challenge. Simultaneous comparative CI data points were collected from transpulmonary thermodilution (TD) and ECOM. Correlations were determined by linear regression. Bland-Altman analysis was used to compare the bias, precision, and limits of agreement. The percentage error was calculated. Pulse-pressure variations (PPVs) and stroke-volume variations (SVVs) before fluid challenge were collected to assess their discrimination in predicting fluid responsiveness. A weak but statistically significant relationship was found between CI(TD) and CI(ECOM) (r = 0.31, p = 0.03). Bias, precision, and limits of agreement between CI(TD) and CI(ECOM) were 0.08 L/min/m(2) (95% confidence interval, -0.11 to 0.27), 0.68 L/min/m(2), and -1.26 to 1.42 L/min/m(2), respectively. The percentage error was 51%. A nonsignificant positive relationship was found between percent changes in CI(TD) and CI(ECOM) after fluid challenge (r = 0.37, p = 0.06). Areas under the ROC curves for both PPV and SVV to predict fluid responsiveness were 0.86 (95% confidence interval, 0.67-1.06) and 0.89 (95% confidence interval, 0.74-1.04, respectively; p = 0.623). Continuous measurements of CI under dynamic conditions are consistent and easy to obtain with ECOM although not interchangeable with transpulmonary thermodilution. SVV given by ECOM is a dynamic parameter that predicts fluid responsiveness with good accuracy and discrimination.

Hemodynamic Changes Induced by Pneumoperitoneum and Measured With ECOM

Laparoscopic surgery presents unique hemodynamic challenges for the anesthetic management of patients. Hemodynamic changes induced by pneumoperitoneum were measured using a new noninvasive device, the Endotracheal Cardiac Output Monitor (ECOM) (ConMed Corp, Utica, NY). This monitor provides measurements—including cardiac output (CO), systemic vascular resistance (SVR), and stroke volume variation (SVV)—that were previously unavailable noninvasively. A better understanding of the applicability and reliability of this new technology in the clinical setting is important for patient safety. CONCLUSIONS

Cardiac Output Determination From Endotracheally Measured Impedance Cardiography: Clinical Evaluation of Endotracheal Cardiac Output Monitor

To evaluate the accuracy, precision, and trending of a new endotracheally sourced impedance cardiography-based cardiac output (CO) monitor (ECOM; ConMed Corp, Irvine, CA). Two university hospitals. Thirty patients scheduled for elective coronary artery bypass graft (CABG) surgery. All patients received a pulmonary artery catheter (PAC), arterial catheter, endotracheal CO monitor (ECOM), endotracheal intubation, and transesophageal echocardiographic monitoring. ECOM CO was compared with CO measured with pulmonary artery thermodilution, and left ventricular CO measured with transesophageal echocardiography. One hundred forty-five pairs of triplicate CO measurements using intermittent bolus pulmonary artery thermodilution (TD) and ECOM were compared at 5 distinct time points: postinduction, postinduction passive leg raise, poststernotomy, post-CABG completion, and post-chest closure. Eighty-seven pairs of triplicate CO measurements using transesophageal echocardiography were obtained at 3 time points: postinduction, post-CABG completion, and post-chest closure and compared with ECOM- and PA-derived CO measurements. The measurements at each time point were compared by using Bland-Altman and polar plot analyses. The mean CO ranged from 2.16 to 9.41 L/min. ECOM CO, compared with TD CO, revealed a bias of 0.02 L/min, 95% limits of agreement of -2.26 to 2.30 L/min, and a percent error of 50%. ECOM CO showed trending with TD CO with 91% and 99% of values within 0.5L/min and 1 L/min limits of agreement, respectively. ECOM CO, compared with TEE CO, revealed a bias of -0.25 L/min, 95% limits of agreement of -2.41 to 1.92 L/min, and a percent error of 48%. ECOM CO showed trending with TEE CO with 83% and 95% of values within 0.5L/min and 1 L/min limits of agreement, respectively. ECOM CO shows an acceptable bias with wide limits of agreement and a large percent error when compared with TD CO or TEE CO; however, it shows acceptable trending of CO to both modalities in patients undergoing cardiac surgery. Further studies are required to evaluate ECOM in other patient populations and clinical situations.

Comparison of the Endotracheal Cardiac Output Monitor to Thermodilution in Cardiac Surgery Patients

To compare cardiac output (CO) measurements from a novel endotracheal bioimpedance cardiac output monitor device (ECOM; ConMed, Irvine, CA) to simultaneous pulmonary artery thermodilution (TD) CO. Prospective study. One academic hospital. Forty volunteer patients undergoing cardiac surgery. Intraoperative CO measurements. Simultaneous comparative data points were collected from ECOM and TD at 4 periods: post-induction, post-sternotomy, post-cardiopulmonary bypass, and post-chest closure. The mean CO(TD) was compared with CO(ECOM) for each operative period then assessed for agreement by linear regression, Bland-Altman analysis, and percent error methods. There were 35 men (87.5%) with a mean age of 66 ± 10.7 years in the present study population. R values (p value) for the 4 time periods were 0.50 (0.002), 0.33 (0.035), 0.42 (0.007), and 0.48 (0.002). Bias and 95% limits of agreement in L/min were -0.11 (-2.40 to 2.18), 0.04 (-2.57 to 2.65), -0.06 (-2.86 to 2.74), and 0.02 (-2.42 to 2.45). Percent errors of the 4 time periods were 51%, 53%, 50%, and 48%. ECOM did not adequately agree with TD in patients undergoing cardiac surgery.

Endotracheal cardiac output monitor.

The endotracheal cardiac output monitor (ECOM) is a new device that uses an endotracheal tube with multiple electrodes to measure cardiac output (CO). It measures the changes in electrical impedance caused by pulsatile blood flow in the aorta. The system was tested for safety and efficacy in 10 swine. Swine (60-80 kg) were chronically instrumented with a transit time flow probe on the ascending aorta and vascular occluders on the vena cava and pulmonary artery. After a minimum recovery of 4 days, the animals were anesthetized and intubated with an ECOM endotracheal tube. CO measurements from the ECOM system were compared to transit time flow probe measurements using linear regression and Bland-Altman analysis. Three different inotropic states were studied: (1) baseline; (2) increased (dobutamine); and (3) decreased (esmolol). CO was changed at each inotropic state by impeding left ventricular filling with the vena cava or pulmonary artery occluders. CO values between 0 and 15 l/min were studied. Pigs were studied for 24 h consecutively. There was no deterioration of the impedance signal with time and no tracheal injury from the ECOM electrodes. There is a linear relationship between the ECOM and transit time flow probe CO between 0 and 15 l/min (slope = 0.94; intercept = 0.15 l/min; R2= 0.77). The mean difference between the two measures (bias) is 0.15 l/min and the SD is 1.34 l/min. The limits of agreement are -2.53 to 2.82 l/min. Endotracheal CO monitor is a promising technology that needs further evaluation in clinical trials.