Preventing low blood pressure after spinal anesthesia with a small dose of ketamine in orthopedic surgery

Impact of Sub-anesthetic Dose of Ketamine in the Prevention of Post Spinal Hypotension in Patients Undergoing Orthopedic Surgeries

NA · Ain Shams University · NCT06995690

This trial will test if a single sub‑anesthetic IV dose of ketamine given before spinal anesthesia can prevent low blood pressure in adults having elective orthopedic surgery.

Quick facts

PhaseNA
Study typeInterventional
Enrollment30 (estimated)
Ages18 Years and up
SexAll
SponsorAin Shams University (other)
Locations1 site (Cairo)
Trial IDNCT06995690 on ClinicalTrials.gov

What this trial studies

This is a randomized, double‑blind, placebo‑controlled trial comparing 0.5 mg/kg IV ketamine to volume‑matched normal saline given over 20 minutes before spinal anesthesia for elective orthopedic procedures. All participants receive standard spinal anesthesia with 0.5% heavy bupivacaine plus fentanyl, and the primary outcome is incidence of hypotension defined as a mean arterial pressure drop >20% from baseline. Secondary outcomes include bradycardia, nausea, vomiting, hallucinations, and total vasopressor dose. Participants are ASA I–II adults with BMI <35 kg/m2 and operations lasting 1–3 hours.

Who should consider this trial

Good fit: Adults (≥18 years) with ASA physical status I–II who are scheduled for elective orthopedic surgery under spinal anesthesia, have BMI <35 kg/m2, and expect operations of 1–3 hours are ideal candidates.

Not a fit: Patients with cardiovascular or pulmonary disease, preexisting hypotension, or those not receiving spinal anesthesia are unlikely to benefit from this intervention.

Why it matters

Potential benefit: If successful, this approach could reduce the frequency of post‑spinal hypotension and lower the need for rescue vasopressors, improving safety during spinal anesthesia.

How similar studies have performed: Prior small trials and physiologic studies have suggested low‑dose ketamine can support blood pressure during neuraxial anesthesia, but results have been limited and somewhat mixed.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients American Society of Anesthesiologists Physical Status (ASA) I to II undergoing orthopedic surgeries under spinal anesthesia.
* Both Sexes.
* Patients aged equal to or above 18 years.
* Body mass index \<35 kg/m2
* Duration of operation from 1 hour to 3 hours

Exclusion Criteria:

* Patients' refusal of procedure or participation in the study.
* Patients with contraindication to spinal anesthesia.
* Patients with cardiovascular or pulmonary disease.
* Patients with pre-procedural hypotension (systolic arterial pressure less than 90 mmHg and/or mean arterial pressure less than 60 mmHg).
* Patients aged below 18 years.
* Duration of operation below 1 hour or above 3 hours.

Where this trial is running

Cairo

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Post-spinal Hypotension, Orthopedic Surgery, Spinal Aneshtesia, Ketamine, Sub-anesthetic dose, Hypotension prevention, Neuraxial anesthesia, Hemodynamic stability

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.