The effect of fasting duration on the circulating blood volume - The effect of fasting duration on the circulating blood volume

We hypothesized that the preoperative volume deficit associated with a 2 h oral intake restriction is smaller than that associated with a 4 h restriction. We tested this hypothesis using the SVV following anesthetic induction. The primary outcome was the difference between the two groups in the volume required to achieve recovery to an SVV value of < 13% With respect to the primary outcome, a greater amount of infusion was required in the 4 h restriction group (2.2 ml/kg) than in the 2 h restriction group (1.7 ml/kg), without statistical significance (P = 0.378). Our study demonstrated that the preoperative volume deficit after a 2 h liquid intake restriction is comparable to that after a 4 h restriction.