Benefits of Drinking Clear Fluids Until Called to the Operating Room in Adult Surgical Patients (HYDRATE)

A Pilot Study to Test Benefits of Drinking Clear Fluids Until Called to the Operating Room in Adult Surgical Patients

The purpose of this study is to show if - compared to standard practice - allowing adults undergoing surgical procedures under anaesthesia care to drink clear fluids up to a volume of 200 ml between 2 h prior to the operation and the call to operation room (approximately 30 min prior to anaesthesia induction) will decrease patient thirst and increase patient satisfaction.

Study Overview

• Status: Completed
• Conditions: Anesthesia; Aspiration; Thirst; Due to Deprivation of Water
• Intervention / Treatment: Behavioral: Additional pre-OP-visit; Behavioral: Liberal fasting regime

• Study Type: Interventional
• Enrollment (Actual): 174
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Germany
  • Bavaria
    • Würzburg, Bavaria, Germany, 97080
      • Wuerzburg University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Adult patients (≥ 18 years)
2. American Society of Anesthesiologists (ASA) physical status classification I-III
3. Undergoing surgical procedure under anaesthesia care: general anaesthesia, regional anaesthesia, combined anaesthesia or monitored anaesthesia care.

The proportion of Patients undergoing general or combined anaesthesia is aimed to exceed 75%

Exclusion Criteria:

1. Absolute indication for rapid sequence induction including but not limited to:

   1. Bowel obstruction including ileus
   2. Stricture and oesophageal disorders including achalasia
   3. Recent polytrauma or trauma of the upper gastrointestinal tract
   4. Acute abdomen/peritonitis including active gastrointestinal bleeding

2. Relative indication for (modified) rapid sequence induction includes, but is not limited to:

   1. Symptomatic gastroesophageal reflux disease, independent of food intake and persistent under medical treatment (PPI)
   2. Hiatus hernia or upside down stomach
   3. Upper gastrointestinal tumour
   4. History of upper gastrointestinal surgery (oesophageal, gastric, duodenum, pancreatic)
   5. Medically confirmed gastroparesis
   6. Severe obesity, defined as body mass index ≥ 40 kg/m2
3. Dysphagia
4. Renal replacement therapy
5. Fluid restriction therapy
6. Pregnancy
7. Expected need for postoperative mechanical ventilation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Usual care; Fasting instructions as given by anaesthesiologist according to national guidelines (6 h solid meal and thick liquids, 2 h clear fluids).
Active Comparator: Instructed guideline adherence; Patients should not involuntarily fast fluids for longer than 2 h.	Behavioral: Additional pre-OP-visit; OP-schedule is closely monitored and patients will be visited to support and encourage them in drinking clear fluids.
Experimental: Experimental intervention; Patients should not involuntarily fast fluids for longer than 30 min.	Behavioral: Additional pre-OP-visit; OP-schedule is closely monitored and patients will be visited to support and encourage them in drinking clear fluids.; Behavioral: Liberal fasting regime; Patients may drink up to 200 ml clear fluids between 2 h prior to the surgery and the call to operation room.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Thirst	At any stage after your hospital admission have you had the following: Thirst (No/ Yes, moderate/ Yes, severe)	Prior to induction of anaesthesia

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total number of protocol deviations per group	Outcome assessment successfully blinded Real fluid fasting time is less than allocated fluid fasting time	From enrollment until last Follow-up is concluded at up to 48 hours post surgery
Fluid fasting time	Actual fluid fasting time in hours	Prior to induction of anesthesia
RASS	Richmond Agitation Sedation Scale. A scale from -5 to +4 is used. Negative values indicate a sedated state. Positive values indicate an agitated state.	2 hours after end of surgery
CAM-ICU	Confusion Assessment Method for the Intensive Care Unit.	2 hours after end of surgery
Headache	At any stage after your hospital admission have you had the following: Headache (No/ Yes, moderate/ Yes, severe)	Prior to induction of anesthesia and 2 hours after end of surgery
Change of systolic blood pressure on induction of anesthesia	The difference between the highest value before induction of anesthesia and the lowest value after induction of anesthesia will be reported.	5 minutes prior and 15 minutes after induction of anesthesia
Change of diastolic blood pressure on induction of anesthesia	The difference between the highest value before induction of anesthesia and the lowest value after induction of anesthesia will be reported.	5 minutes prior and 15 minutes after induction of anesthesia
Change of mean arterial pressure on induction of anesthesia	The difference between the highest value before induction of anesthesia and the lowest value after induction of anesthesia will be reported.	5 minutes prior and 15 minutes after induction of anesthesia
Vasopressor	Use of Vasopressors	Within 15 minutes after induction of anesthesia
Blood glucose level	Blood glucose level	At induction of anesthesia (Values assessed within 15 minutes prior and 15 minutes after induction of anesthesia will be accepted)
Intravenous catheter placement	Number of attempts for placing a (first) peripheral intravenous catheter (only applicable if a peripheral intravenous catheter needs to be placed)	Between admission to the operation room and induction of anesthesia
Postoperative nausea and vomiting	Postoperative nausea and vomiting is a composite endpoint of the following dimensions: Vomiting, retching, nausea, and/or use of rescue medication.	2 hours after end of surgery
Unplanned ICU/IMC	Unplanned intensive/intermediate care unit stay due to respiratory complications	From end of surgery until last Follow-up is concluded at up to 48 hours post surgery
Number of Participants with confirmed bronchopulmonary aspiration	If relevant bronchopulmonary aspiration is suspected, it needs to be confirmed by bronchoscopy or radiology imaging up to 48 hours after anaesthesia procedure	From induction of anesthesia until last Follow-up is concluded at up to 48 hours post surgery
All cause mortality	Death within observation period	From end of surgery until last Follow-up is concluded at up to 48 hours post surgery
Change of heart rate on induction of anesthesia	The difference between the highest value before induction of anesthesia and the lowest value after induction of anesthesia will be reported.	5 minutes prior and 15 minutes after induction of anesthesia
Patient satisfaction	Patient satisfaction, operationalized using the Bauer Satisfaction Questionnaire, includes 10 ordinal items with 3 levels (where higher values indicate unfavourable outcomes), 5 items on a Likert scale with 4 levels (where lower values indicate unfavourable outcomes), and one binary item.	2 hours after end of surgery

Collaborators and Investigators

• Sponsor: Wuerzburg University Hospital
• Investigators: Study Director: Patrick Meybohm, Prof. Dr., University Hospital Würzburg, Department of Anaesthesiology, Intensive Care, Emergency and Pain Medicine, Oberdürrbacher Str. 6, 97080 Würzburg, Germany; Principal Investigator: Tobias E Haas, Dr., University Hospital Würzburg, Department of Anaesthesiology, Intensive Care, Emergency and Pain Medicine, Oberdürrbacher Str. 6, 97080 Würzburg, Germany

Study record dates

Study Major Dates

• Study Start (Actual): July 24, 2024
• Primary Completion (Actual): November 4, 2024
• Study Completion (Actual): November 4, 2024

Study Registration Dates

• First Submitted: January 5, 2024
• First Submitted That Met QC Criteria: February 9, 2024
• First Posted (Actual): February 12, 2024

Study Record Updates

• Last Update Posted (Actual): May 25, 2025
• Last Update Submitted That Met QC Criteria: May 20, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: Surgery; Headache; Dehydration; Postoperative Nausea and Vomiting; Delirium; Satisfaction, Patient
• Other Study ID Numbers: HYDRATE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No