The authors of a study, published in Annals of Surgery investigated this in 92,094 patients undergoing noncardiac surgery with endotracheal intubation. The amount of fluid administered was divided into five groups, ranging from the most restrictive (< 900 mL) to most liberal (> 2700 mL).

The investigators reported a U-shaped curve, with higher 30-day mortality being associated with the most restrictive and most liberal fluid administration patterns. The lowest overall mortality was observed in the second quintile (fluid intake > 900 to 1100 mL). This quintile had the lowest frequency of respiratory complications and the shortest postoperative length of stay; quintile four (fluid intake > 1750 to 2700 mL) had the lowest frequency of acute renal injury.