This document describes and defines specifications for BoMedís
TEBCO Noninvasive Cardiac Output Module. TEBCO connects to the patient via four
pairs of special TEB, dual, pre-gelled, disposable electrodes. TEBCO employs
all-digital signal processing. It provides cardiac index, stroke index, heart
rate, respiratory rate and 6 other cardiodynamic parameters, together with ECG
and three Thoracic Electrical Bioimpedance (TEB) digitized analog signals. The
data are transmitted to the host system via a serial, optoisolated
TEBCO (Thoracic Electrical Bioimpedance Cardiac Output) is a printed circuit board (PCB), containing insulated electronic circuitry for ECG detection, the circuitry for TEB detection, measurement and digital processing, and the optoisolated, serial communication circuitry. On the input side, TEBCO is connected to the patient via a special, 10 ft (3 m) long patient cable and four pairs of HSI proprietary, disposable solid gel TEB electrodes, placed along the frontal plane on the patientís neck and lower thorax. The output of TEBCO is a standard serial RS-232 or USB port, communicating the data at 9600 baud to the host system. The data consist of four digitized analog signals, sent out continuously, and of the digital values of ten cardiodynamic and respiratory parameters, transmitted once for every 16 accepted heart beats and/or for every heart beat (software selectable).
5.5 x 9.1 x 0.6 inch (140 x 231 x 15 mm). Four-layer PCB with surface
mounted components on one side.
Weight: 6 oz (170 g)
Cardiac Output& Accuracy:
+ 20% (comparable with the accuracy of thermodilution method)
40 - 222 beats/min
12 - 48
Each electrode pair consists of one measurement current electrode and one ECG/TEB sensing electrode. The preferable location of the four sensing electrodes is at the following thoracic landmarks: Two at the intersection of frontal plane and the line of the root of the neck, two at the intersection of frontal plane (midaxillary line) and the xiphoid process level. The measurement current electrodes are placed as follows: Each neck electrode is 5 cm (2 inches) above its corresponding sensing electrode, each upper abdominal electrode is 5 cm below the corresponding xiphoid process level sensing electrodes.
Analog Signals (digitized):
1) ECG @ 20 msec/sample
2) dZ/dt @ 20 msec/sample
3) Z @ 20 msec/sample
4) dZ/dt resp @ 20 msec/sample
Cardiodynamic and respiratory parameters:
Heart Rate (HR) [beats/min] +1 beat/min
Ventricular Ejection Time (VET) [sec] +10 msec
Pre-ejection Period (PEP) [sec] + 10 msec
Thoracic Fluid Conductivity (TFC) [1/] +5%
Ejection Phase Contractility Index (EPCI) [1/sec] +10%
Inotropic State Index (ISI) [1/sec/sec] +10%
Ejection Fraction (EF) estimate [%]
*Stroke Index (SI) [ml/beat/m] + 20%
*Cardiac Index (CI) [liters/min/m] + 20%
Respiratory Rate (RR) [breaths/min] + 0.2 breath/min
* Transmitted SI and CI values are standardized for a 180 cm @ 80 kg male and must be recalculated by the host system for actual gender and body habitus.
Upon software initiation by the host system, TEBCO produces simulated ECG and TEB signals @ HR = 100 beats/min, RR = 25 breaths/min, TFC = 0.033/ , (dZ/dt)max = 1.5 /sec and VET = 260 msec.
TEB Measurement Current:
7 ĶA RMS @ 65 kHz
DC Power Supplies Requirements:
Host System: + 5 V @ 600 mA for USB communication
2.5 W (USB Communication)
Any relative humidity without condensation
0 - 50oC