Pre-op Fluid Study

Effect of Pre-operative Intravenous Crystalloids on Post-Induction Blood Pressure

Theoretical framework:

Hypotension during surgery directly impacts patients' postoperative outcomes and complications. Decrease in blood pressure measurements secondary to anesthetic drugs is an expected scenario in most surgical cases. Moreover, hypovolemia secondary to fast pre-operative period may facilitate post-induction hypotension which can be compensated by fluid bolus pre-operatively.

Study Overview

• Status: Active, not recruiting
• Conditions: Anesthesia; Hypotension Drug-Induced
• Intervention / Treatment: Other: Crystalloid Solutions

Detailed Description

Objectives:

The purpose of the study is to conduct a randomized intervention cohort study using pre-operative fluid therapy to assess its effect on blood pressure during the post-induction period. The investigators are testing the hypothesis that preoperative Crystalloid bolus decreases the risk of post-induction hypotension, specifically the time-weighted average (TWA) mean arterial pressure (MAP) under 65 mmHg during the first 20 minutes after anaesthetic induction or until surgical incision, whichever is first, compared to standard of care, which is minimal fluid administration in the pre-operative period.

Methods:

The investigators will conduct a randomized intervention cohort study using pre-operative fluid therapy to assess its effect on blood pressure during the post-induction period. The intervention group will receive a bolus of a balanced crystalloid solution within 60 ± 15 minutes before induction of anaesthesia. The control group will be treated according to the current clinical standard of care. The investigators will compare the time-weighted average (TWA) mean arterial pressure (MAP) under 65 mmHg during the first 20 minutes after anaesthetic induction or until surgical incision (whichever comes first).

• Study Type: Interventional
• Enrollment (Actual): 550
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Austria
  • Styria
    • Graz, Styria, Austria, 8036
      • Medical University Graz
  • Vienna
    • Vienna, Vienna, Austria
      • Medical University Vienna

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 45 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Scheduled for major non-cardiac surgery
2. Having general anaesthesia
3. Are designated ASA physical status ≥2 (ranging from mild systemic disease through severe systemic disease that is a constant threat to life)

4. Subject to at least one of the following risk factors:

   1. Age ≥ 65 years
   2. History of peripheral arterial surgery
   3. History of coronary artery disease
   4. History of stroke or transient ischemic attack
   5. Serum creatinine >175 µmol/L (>2.0 mg/dl)
   6. Diabetes requiring medication
   7. Current smoking or 15 pack-year history of smoking tobacco
   8. Preoperative high-sensitivity troponin T >14 ng/L or troponin I equivalent, defined as ≥15 ng/L (Abbott assay),75 19 ng/L (Siemens assay, [Borges, unpublished]), or 25% of the 99% percentile for other assays;
   9. B-type natriuretic protein (BNP) ≥ 80 ng/L or N-terminal B-type natriuretic protein (NT-ProBNP) ≥ 200 ng/L.76,77
   10. History of atrial fibrillation
   11. Chronically taking at least one anti-hypertensive medication

Exclusion Criteria:

1. Are scheduled for carotid artery surgery
2. Are scheduled for intracranial surgery
3. Are scheduled for pheochromocytoma surgery
4. Require preoperative intravenous vasoactive medications
5. Active decompensated congestive heart failure (documented EF < 30%)
6. Chronic Kidney Disease (eGFR< 30 mL/min)
7. History of organ transplantation
8. Rectal surgical procedures
9. Patients receiving preoperative bowel preparation
10. Severe pulmonary edema

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control; Patients will receive the balanced crystalloid solution according to the current clinical standard of care.
Experimental: Intervention; The investigators will start a balanced crystalloid solution (in detail we will administer 500ml if the actual body weight is ≤90 kg: the investigators will administer 1000 ml if the actual body weight is >90 kg:) within 60 +/- 15 minutes before induction of anesthesia in the pre-operative area or at the ward, as appropriate.	Other: Crystalloid Solutions; As above

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Post-induction MAP	Post-induction hypotension is defined as TWA MAP under 65 mmHg during post-induction period. We will use non-invasive continuous arterial blood pressure monitoring as feasible. Anesthesia staff and nurses will be blinded, and standard of care will be provided. Data from the monitor will be recorded in the anesthesia record. We will be using standard intraoperative patient monitoring system. This system will measure 3 lead ECG (electrocardiogram), SpO2 (Arterial oxygen saturation), and number of respirations continuously. The primary outcome will be the TWA MAP under 65 mmHg during the post-induction period.	60 +/- 15 minutes before induction of anesthesia until the first 20 minutes after anesthetic induction or until surgical incision (whichever comes first)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vasopressors	The major outcome for the vasopressor requirement will be a binary variable representing the use of vasopressors during the post-induction period. Additionally, we will compare the amount of vasopressors between the groups.	60 +/- 15 minutes before induction of anesthesia until the first 20 minutes after anesthetic induction or until surgical incision (whichever comes first)
Cardiac Output (CO)	The major outcome for the non-invasively measured CO will be a continuous measurement throughout pre-induction, induction of anesthesia and post-induction as feasible.	60 +/- 15 minutes before induction of anesthesia until the first 20 minutes after anesthetic induction or until surgical incision (whichever comes first)

Collaborators and Investigators

• Sponsor: Medical University of Graz
• Investigators: Principal Investigator: Andrea Kurz, Prof, Medical University of Graz, Austria

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2021
• Primary Completion (Actual): June 19, 2024
• Study Completion (Estimated): November 30, 2025

Study Registration Dates

• First Submitted: October 1, 2021
• First Submitted That Met QC Criteria: October 14, 2021
• First Posted (Actual): October 15, 2021

Study Record Updates

• Last Update Posted (Actual): November 21, 2025
• Last Update Submitted That Met QC Criteria: November 18, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Keywords: Perioperative fluid management; Postinduction hypotension
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Hypotension; Pharmaceutical Preparations; Isotonic Solutions; Solutions; Crystalloid Solutions
• Other Study ID Numbers: 21

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

For electronic data management we will use the CLINCASE software (Quadratek, Berlin, Germany). Data storage and back up will be provided by IT Systems & Communications (ITSC) - IT4Science (Medical University of Vienna). Access to data is strictly controlled and will only be provided to the Sponsor (Medical University of Graz and the Medical University of Vienna), the study investigators and the ethic commission (Ethic commission of the Medical University of Vienna).

All entries and changes in the CLINCASE software will be tracked.

• IPD Sharing Time Frame: The data will be transferred immediately after patient's enrolment and will be available until the end of the study for both sponsors (Medical University of Graz, Medical University of Vienna)
• IPD Sharing Access Criteria: Access will only be provided to the Sponsor (Medical University of Graz and the Medical University of Vienna), the study investigators and the ethic commission (Ethic commission of the Medical University of Vienna).
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

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