Low-dose Norepinephrine Infusion for Prevention of Post-induction Hypotension in Emergency Surgery for Peritonitis

Protocolized Low-dose Norepinephrine Infusion for Prevention of Post-induction Hypotension in Adults Undergoing Emergency Surgery for Secondary Peritonitis: A Randomized Double-blind Placebo-controlled Trial

This study tests whether giving a low-dose norepinephrine infusion just before induction of anesthesia can reduce low blood pressure during emergency surgery for peritonitis. Adults with secondary peritonitis who are scheduled for emergency surgery and have stable blood pressure after initial resuscitation will be randomly assigned to receive either norepinephrine or placebo (normal saline) during induction of anesthesia. The main outcome is the cumulative time spent with mean arterial pressure (MAP) below 65 mmHg from the start of propofol administration to 10 minutes after endotracheal intubation. The study will also evaluate rescue vasopressor use, heart rate changes, drug-related adverse events, and selected early postoperative outcomes.

Study Overview

• Status: Not yet recruiting
• Conditions: Secondary Peritonitis; Post-induction Hypotension
• Intervention / Treatment: Drug: Norepinephrine (0.05 μg/kg/min); Other: Placebo

Detailed Description

The study is a single-center, randomized, double-blind, placebo-controlled interventional trial conducted at the Center for Anesthesia and Surgical Intensive Care, Bach Mai Hospital, Hanoi, Vietnam.

Adults undergoing emergency surgery for secondary peritonitis often have marked hemodynamic vulnerability during induction of general anesthesia because of systemic inflammation, vasodilation, capillary leak, and relative hypovolemia. Propofol-based induction may further reduce arterial pressure and organ perfusion in this setting.

Participants who meet eligibility criteria and have a mean arterial pressure (MAP) of at least 65 mmHg after initial resuscitation, without ongoing vasopressor support, will be enrolled and randomized 1:1 to a norepinephrine infusion group or a placebo group.

In the intervention group, norepinephrine will be infused at 0.05 micrograms/kg/min starting 3 minutes before fentanyl. In the placebo group, 0.9% sodium chloride will be infused with the same presentation, timing, and pump settings.

All participants will undergo a standardized induction protocol with fentanyl, titrated propofol, rocuronium, arterial line monitoring before induction, and protocolized hemodynamic rescue treatment.

The primary endpoint is the cumulative duration of MAP below 65 mmHg during the induction-intubation window, defined from the start of propofol administration to 10 minutes after endotracheal intubation. Secondary endpoints include the incidence of MAP below 65 and below 55 mmHg, the largest decrease in MAP from baseline, heart-rate changes, rescue vasopressor requirements, atropine use, and predefined early postoperative outcomes.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Thang Toan Nguyen, PhD; Phone Number: +084916874795; Email: nguyentoanthang@hmu.edu.vn

Study Locations

• Vietnam
  • Hanoi, Vietnam
    • Center for Anesthesia and Surgical Intensive Care, Bach Mai Hospital
    • Contact: Center for Anesthesia and Intensive Care, Bach Mai Hospital. Center for Anesthesia and Intensive Care, Bach Mai Hospital.; Phone Number: +084869587720; Email: trungtamgaymehoisuc@bachmai.edu.vn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 18 years or older.
• Secondary peritonitis requiring emergency surgery under general anesthesia with endotracheal intubation.
• Planned induction with fentanyl, propofol, and rocuronium according to the study protocol.
• Hemodynamically stabilized after initial resuscitation, with MAP at least 65 mmHg and no ongoing vasopressor infusion before induction.
• ASA physical status I to III.
• Written informed consent from the participant or a legally authorized representative.

Exclusion Criteria:

• Allergy or contraindication to norepinephrine, propofol, fentanyl, or rocuronium.
• Severe cardiovascular disease likely to confound hemodynamic assessment, including decompensated heart failure, acute coronary syndrome, severe arrhythmia, severe valvular disease, or major cardiomyopathy.
• Ongoing vasopressor therapy before induction.
• Shock before surgery, including hypovolemic, septic, or cardiogenic shock.
• Severe hypertension before induction (systolic blood pressure >180 mmHg or mean arterial pressure >110 mmHg).
• Severe peripheral vascular disease or clinically significant limb ischemia.
• Current monoamine oxidase inhibitor use.
• Pregnancy or breastfeeding.
• Contraindication to arterial catheter placement.
• Refusal of consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low-dose norepinephrine infusion; Participants receive a norepinephrine infusion at 0.05 micrograms/kg/min starting 3 minutes before fentanyl during standardized induction of general anesthesia.	Drug: Norepinephrine (0.05 μg/kg/min); Norepinephrine prepared in a blinded syringe and infused continuously at 0.05 micrograms/kg/min starting 3 minutes before fentanyl during induction of general anesthesia. Infusion is adjusted or temporarily stopped according to the protocol-defined hemodynamic safety algorithm.
Placebo Comparator: 0.9% sodium chloride infusion; Participants receive 0.9% sodium chloride with the same presentation, timing, and infusion settings as the intervention arm during standardized induction of general anesthesia.	Other: Placebo; Placebo: 0.9% Sodium Chloride prepared in a blinded syringe and administered with the same timing, presentation, and pump settings as the active study drug.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cumulative duration of MAP below 65 mmHg during induction	Total time with mean arterial pressure below 65 mmHg, derived from time-stamped arterial line data after removal of artifacts.	From start of propofol administration to 10 minutes after endotracheal intubation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of MAP below 65 mmHg	Proportion of participants with at least one episode of MAP below 65 mmHg.	From start of propofol administration to 10 minutes after endotracheal intubation
Incidence of severe hypotension (MAP below 55 mmHg)	Proportion of participants with at least one episode of MAP below 55 mmHg.	From start of propofol administration to 10 minutes after endotracheal intubation
Largest decrease in MAP from baseline	Maximum absolute and relative reduction in MAP compared with baseline.	From baseline before study-drug infusion to 10 minutes after endotracheal intubation
Number of Participants Requiring Rescue Vasopressor	Number of participants who receive any rescue vasopressor to treat hypotension during the induction-intubation study window.	From baseline before study-drug infusion to 10 minutes after endotracheal intubation
Number of Participants With Bradycardia	Number of participants with bradycardia during the induction-intubation study window. Bradycardia should be defined according to the protocol-specified threshold	From start of propofol administration to 10 minutes after endotracheal intubation
Postoperative lactate concentration	Arterial or venous lactate concentration used as an exploratory marker of tissue perfusion and physiologic recovery	Preoperative baseline and within 24 hours after surgery
Total Rescue Vasopressor Dose	Total dose of rescue vasopressor administered to treat hypotension during the induction-intubation study window.	From baseline before study-drug infusion to 10 minutes after endotracheal intubation
Number of Participants With Tachycardia	Number of participants with tachycardia during the induction-intubation study window. Tachycardia should be defined according to the protocol-specified threshold.	From start of propofol administration to 10 minutes after endotracheal intubation
Number of Participants Requiring Atropine	Number of participants who receive atropine according to the protocol-defined criteria during the induction-intubation study window.	From start of propofol administration to 10 minutes after endotracheal intubation
Number of Participants With Clinically Significant Arrhythmias	Number of participants with clinically significant arrhythmias during the induction-intubation study window.	From start of propofol administration to 10 minutes after endotracheal intubation
Number of Participants Admitted to the Intensive Care Unit After Surgery	Number of participants transferred to the intensive care unit (ICU) after surgery.	From end of surgery to hospital discharge
Number of Participants With Early Postoperative Complications	Number of participants with predefined early postoperative complications after surgery.	From end of surgery to hospital discharge
Postoperative Length of Stay	Postoperative length of hospital stay from the end of surgery until hospital discharge.	From end of surgery to hospital discharge

Collaborators and Investigators

• Sponsor: Bach Mai Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): April 1, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): October 1, 2026

Study Registration Dates

• First Submitted: March 29, 2026
• First Submitted That Met QC Criteria: April 7, 2026
• First Posted (Actual): April 14, 2026

Study Record Updates

• Last Update Posted (Actual): April 14, 2026
• Last Update Submitted That Met QC Criteria: April 7, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Norepinephrine; Emergency surgery; General anesthesia; Noradrenaline; Mean arterial pressure; Induction hypotension
• Additional Relevant MeSH Terms: Infections; Digestive System Diseases; Peritoneal Diseases; Intraabdominal Infections; Peritonitis; Organic Chemicals; Hydrocarbons; Hydrocarbons, Cyclic; Hydrocarbons, Aromatic; Amines; Catechols; Phenols; Benzene Derivatives; Alcohols; Amino Alcohols; Ethanolamines; Biogenic Monoamines; Biogenic Amines; Catecholamines; Norepinephrine
• Other Study ID Numbers: TTGMHS-NA-PP-2026-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The investigators have not yet determined whether de-identified individual participant data will be shared. Any future data sharing decision will depend on institutional policy, ethics approval requirements, and participant privacy considerations.

Drug and device information, study documents

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