Introduction :
The pulmonary artery catheter (PAC) has historically been used to
measure the pulmonary capillary wedge pressure
(PCWP)1. This measurement is considered as a surrogate
of left atrial pressure (LAP) and, by extension, left ventricular
end‐diastolic pressure. Various studies have shown that PCWP and LAP
correlate well in patients with cardiovascular
disease2,3. Estimation of LAP is a core component of
the evaluation of left ventricular diastolic
function4. Elevated left ventricular filling pressures
predict long‐term adverse outcomes, even in patients with normal
ejection fractions5. A restrictive diastolic filling
pattern predicts major morbidity and mortality in patients undergoing
cardiac surgery6.
The use of the PAC has been questioned in the perioperative period with
some studies unable to clearly demonstrate clinical benefit. This has
resulted in declining use in the perioperative
period7. Alternative methods like echocardiography has
been used for the noninvasive estimation of PCWP and LAP. Transthoracic
echocardiography (TTE) is non-invasive and is therefore of considerable
appeal as a measurement tool. Various Doppler measurements have been
made in healthy patients and in different disease states, and their
correlation and agreement with PCWP is reasonable. Transesophageal
echocardiography (TEE) is used routinely in cardiac surgery for the
evaluation of hemodynamic conditions, left ventricular function and
valvular function. Few studies8,9 were attempted to
validate correlation and agreement of Doppler measurements using TEE and
PCWP in anaesthetised patients receiving mechanical ventilation. It
should not be assumed that TTE validation will automatically apply to
patients using TEE, although successful validation would be of great
clinical benefit and reduce reliance on the pulmonary artery catheter.