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Updated: Aug 30, 2026
Monitoring Lung Function with Electrical Impedance Tomography in the Intensive Care Unit
Published on: September 6, 2024
The 'TEI-index' is preload dependent and can be measured by transoesophageal echocardiography during mechanical
J T Lutz1, R Giebler, J Peters
1Klinik für Anästhesiologie und Intensivmedizin, Universitätsklinikum Essen, Essen, Germany. juergen.lutz@uni-essen.de
Background And Objective:
The Doppler-derived echocardiographic TEI-index, defined as the sum of the left ventricular isovolumic contraction and isovolumic relaxation times divided by ejection time, quantifies combined systolic and diastolic ventricular functions. The index has been proposed to be independent of arterial pressure and heart rate, implying a broad clinical usefulness. However, it is unclear whether the index is preload independent. We assessed whether and to what degree the TEI-index is altered by left ventricular loading conditions, and the feasibility of measurement by transoesophageal echocardiography during anaesthesia and mechanical ventilation.
Methods:
We studied 17 anaesthetized mechanically ventilated patients with coronary artery disease during variations in left ventricular preload evoked by head-up and head-down tilt, respectively.
Results:
A head-down tilt increasing left ventricular end-diastolic area from 18.8 +/- 4 to 23.7 +/- 4 cm2 (P < 0.05) significantly decreased the TEI-index from 0.5 +/- 0.17 to 0.33 +/- 0.15 (P < 0.05). In contrast, the TEI-index remained unchanged with decreased left ventricular preload (14.4 +/- 3.7 cm2) during head-up tilt.
Conclusions:
An increase in preload decreases the TEI-index indicating its sensitivity to acute increases in left ventricular preload. The TEI-index can be measured perioperatively by transoesophageal echocardiography.
