title: Comparison of transthoracic electrical bioimpedance cardiac output measurement with thermodilution method in post coronary artery bypass graft patients.
abstract: Transthoracic electrical bioimpedance (TEB) has been proposed as a non-invasive, continuous, and cost-effective method of cardiac output (CO) measurement. In this prospective, non-randomized, clinical study, we measured CO with NICOMON (Larsen and Toubro Ltd., Mysore, India) and compared it with thermodilution (TD) method in patients after off-pump coronary artery bypass (OPCAB) graft surgery. We also evaluated the effect of ventilation (mechanical and spontaneous) on the measurement of CO by the two methods. Forty-six post-OPCAB patients were studied at five predefined time points during controlled ventilation and at five time points when breathing spontaneously. A total of 230 data pairs of CO were obtained. During controlled ventilation, TD CO values ranged from 2.29 to 6.74 L/min (mean 4.45 ± 0.85 L/min), while TEB CO values ranged from 1.70 to 6.90 L/min (mean 4.43 ± 0.94 L/min). The average correlation (r) was 0.548 (P = 0.0002), accompanied by a bias of 0.015 L/min and precision of 0.859 L/min. In spontaneously breathing patients, TD CO values ranged from 2.66 to 6.92 L/min (mean 4.66 ± 0.76 L/min), while TEB CO values ranged from 3.08 to 6.90 L/min (mean 4.72 ± 0.82 L/min). Their average correlation was relatively poor (r = 0.469, P= 0.002), accompanied by a bias of -0.059 L/min and precision of 0.818 L/min. The overall percent errors between TD CO and TEB CO were 19.3% (during controlled ventilation) and 17.4% (during spontaneous breathing), respectively. To conclude, a fair correlation was found between TD CO and TEB CO measurements among post-OPCAB patients during controlled ventilation. However, the correlation was weak in spontaneously breathing patients.
authors.affiliation: Department of Anaesthesiology and Critical Care, Escorts Heart Institute and Research Centre Ltd., New Delhi, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Sharma
authors.forename: Ajmer
authors.initials: A
authors.lastname: Singh
authors.forename: Bhuvnesh
authors.initials: B
authors.lastname: Kansara
authors.forename: Anil
authors.initials: A
authors.lastname: Karlekar
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D002302:Cardiac Output / Q000502:physiology*; D047549:Coronary Artery Bypass, Off-Pump; D003422:Critical Care; D004452:Echocardiography; D017097:Electric Impedance; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods*; D010992:Plethysmography, Impedance; D011446:Prospective Studies; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D013318:Stroke Volume / Q000502:physiology; D013815:Thermodilution / Q000379:methods*; D016277:Ventricular Function, Left / Q000502:physiology