Could patient-controlled thirst-driven fluid administration lead to more rapid rehydration than clinician-directed fluid management? An early feasibility study
BACKGROUND: Fluid management is a major factor determining perioperative outcome, yet in reality, fluid administration practice is variable. Thirst however, is a highly sensitive and reliable indicator of fluid deficits. We explored the use of thirst sensation to trigger i.v. fluid boluses to guide individualized fluid management. METHODS: We performed a randomised double crossover trial on 16 healthy male volunteers, of mean age 31 yr and BMI 24.4 kg m-2. Twice, after administrations of oral furosemide (40 mg) and 12 h of oral fluid restriction, participants received a 4-h i.v. fluid infusion. In the experimental arm, participants pressed a trigger to relieve their thirst, administering a 200 ml bolus. In the control arm, i.v. fluid was infused following National Institute for Health and Clinical Excellence (NICE) guidelines at 1.25 ml kg-1 h-1 with a clinician delivered 500 ml i.v. bolus in response to clinical signs of dehydration. Plasma osmolality and urine specific gravity were measured before and after each infusion. RESULTS: More fluid was infused in response to thirst than by adherence to NICE guidelines, with a mean difference of 743 ml (P=0.0005). Thirst-driven fluid administration was fitted to an exponential function of time, plateauing after a mean half-life of 98.8 min. In the experimental arm there was a greater reduction in urine specific gravity and thirst score with mean differences 0.0053 g cm-3 (P=0.002) and 3.3 (P=0.003), respectively. Plasma osmolality demonstrated no fluid overload. CONCLUSIONS: A system delivering i.v. fluid in response to subjective thirst corrects fluid deficits in healthy participants. A clinical feasibility study will assess the potential use of this system in the perioperative setting. CLINICAL TRIAL REGISTRATION: NCT 03176043