Significant effort has been devoted to defining parameters for predicting fluid responsiveness. Our goal was to study the feasibility of predicting fluid responsiveness by transcutaneous partial pressure of oxygen (PtcO ₂ ) in the critically ill patients.

This was a single-center prospective study conducted in the intensive care unit of a tertiary care teaching hospital. Shock patients who presented with at least one clinical sign of inadequate tissue perfusion, defined as systolic blood pressure <90 mmHg or a decrease >40 mmHg in previously hypertensive patients or the need for vasopressive drugs; urine output <0.5 ml/kg/h for 2 h; tachycardia; lactate > 4 mmol/l, for less than 24 h in the absence of a contraindication for fluids were eligible to participate in the study. PtcO ₂ was continuously recorded before and during a passive leg raising (PLR) test, and then before and after a 250 ml rapid saline infusion in 10 min. Fluid responsiveness is defined as a change in the stroke volume ≥10% after 250 ml of volume infusion.

Thirty-four patients were included, and 14 responded to volume expansion. In the responders, the mean arterial pressure, central venous pressure, cardiac output, stroke volume and PtcO ₂ increased significantly, while the heart rate decreased significantly by both PLR and volume expansion. Changes in the stroke volume induced either by PLR or volume expansion were significantly greater in responders than in non-responders. The correlation between the changes in PtcO ₂ and stroke volume induced by volume expansion was significant. Volume expansion induced an increase in the PtcO ₂ of 14% and PLR induced an increase in PtcO ₂ of 13% predicted fluid responsiveness.

This study suggested the changes in PtcO ₂ induced by volume expansion and a PLR test predicted fluid responsiveness in critically ill patients.

Trial registration NCT02083757.