Tidal Volume Challenge to Predict Fluid Responsiveness in Liver Transplant Recipients Ventilated Using Low Tidal Volume.

OBJECTIVES

The low tidal volume ventilatory technique poses limitations on the application of dynamic indices, like pulse pressure and stroke volume variations, in determining fluid responsiveness. This study investigated whether shifts in pulse pressure variation and stroke volume variation following a tidal volume challenge could predict fluid responsiveness in liver transplant recipients facing low tidal volume.

MATERIALS AND

METHODS

We conducted a prospective intervention study in liver transplant recipients ventilated with low tidal volume. Patients received tidal volume challenge (transiently increasing the tidal volume from 6 to 8 mL /kg predicted body weight) at a single time frame, when the patient developed hypotension before administration of fluid bolus or any vasopressor agents, and changes in pulse pressure variation and stroke volume variation were noted. Patients were classified as fluid responders or nonresponders based on whether fluid challenge resulted or did not result in increased stroke volume index of >10 %.

RESULTS

Among the 28 included patients, 12 (42.9 % ) were fluid responders and 16 (57.1 % ) were fluid nonresponders. During the tidal volume challenge, mean changes in pulse pressure and stroke volume variations were 2.00 ± 0.60 and 2.33 ± 0.77 in responders and 1.06 ± 0.44 and 0.87 ±0.62 in nonresponders, respectively. Change in pulse pressure variation with area under the curve was 0.87 (95 % CI, 0.73 -1.00; P = .001 ), with optimal cut-off value of 1.5 indicating sensitivity and specificity of 83.3 % and 87.5 %; change in stroke volume variation with area under the curve was 0.91 (95 % CI: 0.79-1.00, P = < .001 ), with the same cut -off value of 1.5 indicating sensitivity and specificity of 83.3 % and 87.5 %.

CONCLUSIONS

Changes in pulse pressure and stroke volume variations after tidal volume challenge have good predictability of fluid responsiveness in liver transplant recipients ventilated with lung protective ventilation strategy.