Comparative evaluation of stroke volume variation and inferior vena cava distensibility index for prediction of fluid responsiveness in mechanically ventilated patients.

OBJECTIVES

To evaluate the correlation between stroke volume variation (SVV) and inferior vena cava distensibility index (dIVC) as a marker for fluid responsiveness in mechanically ventilated hypotensive intensive care unit (ICU) patients.

METHODOLOGY AND DESIGN

This study is designed as prospective observational study conducted in patients admitted to an ICU who were mechanically ventilated and experienced a hypotensive episode.

INTERVENTION

A fluid challenge of 10 mL/kg ringer's lactate was given over 20 min.

MEASUREMENTS

Hemodynamic parameters as well as SVV, IVCmax, IVCmin, dIVC, and cardiac output (CO), were recorded at a different time interval. An increase in ≥15% of CO was taken as fluid responsiveness.

RESULTS

Out of 67 patients, 67.2% responded to fluid challenge. Pearson's correlation graph at baseline showed a strong positive correlation between dIVC and SVV with r = 0.453, (P < 0.002). Non-responders also had a strong positive correlation (r = 0.474) at the baseline. Bland Altman's analysis of the correlation between dIVC and SVV post-fluid challenge showed a mean difference of - 4.444, with 1.49% of the values falling outside the limits of agreement (18.418 and -27.306). This difference was clinically significant. Pearson's correlation graph post-fluid challenge showed a moderately strong positive correlation between dIVC and SVV with r = 0.298 and P value = 0.047, which was statistically significant. Also, non-responders had a weak correlation as compared to the responder's group, r = 0.364 and P value = 0.095, which was not clinically significant. There was no significant difference in the trend of dIVC and SVV values between the non-surgical and surgical groups, nor was there any gender difference analyzed in the study.

CONCLUSION

This study ascertains the positive correlation between dIVC and SVV and justifies its use in a clinical setting of hypotension suspected to be due to hypovolemia.