Validity of Transesophageal echocardiography in estimating left
ventricular filling pressures in anaesthetised patients undergoing
cardiac surgery
Abstract
Background :The aim of this study was to validate whether pulmonary
capillary wedge pressure estimated using transoesophageal
echocardiography in anaesthetised patients receiving mechanical
ventilation can be comparable to gold standard method of estimating PCWP
by using pulmonary artery catheter. Methods : A cross sectional validity
study conducted in a tertiary care cardiac centre in south India over a
period of 6 months from February 2016 – August 2016 among 100 patients
undergoing cardiac surgery where intraoperative TEE and pulmonary artery
catheter used. In anesthetised patients, after the insertion of TEE
probe, the following echocardiography ratios were calculated: 1) SF = S
⁄ S + D (systolic fraction of pulmonary venous flow 2) Systolic ⁄
diastolic (S ⁄ D ratio) 3) E ⁄ Ea 4) E ⁄ Vp 5) E ⁄ A ratio , for three
consecutive cardiac cycles and averaged by two independent and blinded
observers. All the echo measurements were taken pre cardiopulmonary
bypass at end expiration and during a stable period of hemodynamics.
Simultaneously PCWP was recorded from PAC. The ability of these
variables to predict PCWP was tested for previously determined cutoffs
as per extant guidelines and validity parameters such as sensitivity,
specificity, predictive value of positives, predictive value of
negatives & accuracy were computed. Conclusion : Use of E/A,DT,S/D,SF
ratio & E/Vp reveal poor predictive capacity for detecting high left
sided filling pressures. The use of E/Ea is reasonable to predict an
elevated PCWP especially if the cohort predominantly comprises of
patients with normal ejection fraction