Effect of Anti-histamine in Prevention Systolic Hypotension After Protamine


Protamine remains the anticoagulant of choice for cardiopulmonary bypass (CPB). The process of protamine neutralization of heparin came with the side effects sometimes; it can be life threatening or fetal reaction. The adverse cardiopulmonary response of protamine has been observed during entire history of clinical cardiac surgery. The true mechanism reaction is difficult to defined and the complexity of the clinical situation The classification of protamine reaction has been divided in to main 3 types (transient systemic hypotension secondary to rapid administration, anaphylactic and anaphylactoid reaction and catastrophic pulmonary vasoconstriction.

The reaction from pharmacologic histamine release is the most common type of reaction. Protamine was believed to induce hypotension by this mechanism, and it was demonstrated to release histamine by degranulation of isolated mast cells From the hypothesis that the systemic hypotension cause by the released of histamine. The investigators will measure the serum tryptase which is the enzyme that released from degranulation of human mast cell. Comparing the serum tryptase level of the patient at baseline, 30 min and 60 min after protamine was given.

There for the hypothesis of this study is administrating of H1 and H2 blocker helps attenuate the drop in MAP after protamine is given.

Full Title of Study: “A Randomized Controlled Study Comparing the Prophylactic Effect of histamine1 and Histamine 2 Receptor Blocker in Prevention Systolic Hypotension After Protamine Administration in Cardiac Patient Having Cardiopulmonary Bypass”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: December 1, 2020


  • Drug: Chlorpheniramine and ranitidine
    • Patient will receive intravenous chlorpheniramine and ranitidine prior to protamine.
  • Drug: 0.9% Normal Saline
    • Patient will receive normal saline as placebo.

Arms, Groups and Cohorts

  • Placebo Comparator: 0.9% Normal Saline
    • Syringe No 1 contain normal saline 1 mL Syringe No 2 contain normal saline 2 mL
  • Experimental: Chlorpheniramine and ranitidine
    • Syringe No 1 contain chlorpheniramine 10 mg (1 mL) Syringe No 2 contain ranitidine 50 mg (2 mL)

Clinical Trial Outcome Measures

Primary Measures

  • Blood pressure
    • Time Frame: 37 minutes
    • Systolic and diastolic blood pressure will be recorded every minutes since the start of protamine infusion (in 7 minutes) til 30 minutes after infusion.

Secondary Measures

  • Serum tryptase
    • Time Frame: 60 minutes
    • Serum tryptase will be measured before the administration of protamine and at 30 minutes and 60 minutes after protamine

Participating in This Clinical Trial

Inclusion Criteria

  • ASA physical status 1-3
  • Schedule for open heart surgery

Exclusion Criteria

  • History of allergy to the study drugs or protamine
  • History of previous cardiac surgery or received protamine
  • History of diabetes with insulin therapy

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Mahidol University
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Sirilak Suksompong, MD, Principal Investigator, Mahidol University
  • Overall Contact(s)
    • sirilak Suksompong, MD, 66891534806, ssuksompong5@gmail.com

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