Title: Is there a role for telediastolic dimensions of the LV as an estimate of preload in non-critical patients? A study in volunteers.

Author: Alves DR

Institution: Centro Hospitalar de Lisboa Ocidental, Dept of Anaesthesiology & Intensive Care, Lisboa, Portugal

Text:
Background and Goal of Study: Estimating fluid responsiveness has been established as an important landmark in fluid therapy, and several indices were developed with such in mind. Presently dynamic preload indices gain ground, but many professionals still rely to some extent on static parameters such as telediastolic dimensions of the LV, namely at short axis views. We decided to assess their usefulness by comparing such parameters with fluid the individual ́s fluid responsiveness state as defined by aortic VTI variation with the passive leg raise manoeuvre (var VTIAo PLR).

Materials and methods: We performed echocardiographic (TTE) exams in 31 ASA 1 and 2 volunteers (2 exams per volunteer, each in different days), obtaining data on both LV diastolic diameter in PSLAx view (later also used to estimate telediastolic volume with the Teicholz formula), area at the papillary muscles level in the PSSAx view, and var VTIAo PLR. We then looked for linear
correlations between telediastolic dimensions and VTI variation (Scatter plot, Pearson's correlation coefficient) and finally divided our sample into either fluid responsive and non-fluid responsive individuals (using 2 cutt-offs for varVTIAo PLR described in the literature: 10% and 15%), later
comparing the distribution of telediastolic dimensions in both groups.

Results and discussion: There was no statistically significant linear correlation between any of the telediastolic dimensions and VarVTIAoPLR. There were also no statistically significant differences in
the distribution of telediastolic dimensions between fluid responders and non-fluid responders, as defined by either of the cut-offs used described in the literature.

Conclusions: Even though several studies have emphasized the role of dynamic preload indices and decreased the enthusiasm for static ones such as telediastolic dimensions, they are still used clinically. The present study, however, cannot find a statistically significant relation between these and the validated indices of preload responsiveness for patients breathing spontaneously, which would advise against their use in routine practice.
However, it should be stated that none of our volunteers had extreme deviations in the value of telediastolic dimensions, which consequently does not allow us to infer as to the predictive value of very small ones in critical, haemodynamically unstable patients. Further studies are advised to further clarify the matter in these particular circumstances.