Effect of Intravenous Ketamine Combined With Spinal Anesthesia on Sensory Block Duration Compared to Spinal Anesthesia Alone in Lower Limb Surgeries in Geriatrics.

Effect of Intravenous Ketamine Combined With Spinal Anesthesia on Sensory Block Duration Compared to Spinal Anesthesia Alone in Lower Limb Surgeries in Geriatrics: A Randomized Controlled Double-Blinded Trial.

Effect of Intravenous Ketamine combined with Spinal Anesthesia on Sensory Block

Duration compared to Spinal Anesthesia alone in Lower Limb surgeries in geriatrics:

Study Overview

• Status: Recruiting
• Conditions: IV Ketamine With Spinal Block
• Intervention / Treatment: Drug: Patients will receive 0.2 mg/kg IV of ketamine diluted to 5 ml followed by infusion 0.1 mg/kg/hr as a 20 ml solution; Drug: Patients will receive 5 ml of saline followed by infusion 0.1 ml/kg/hr as a 20 ml solution as a control group

Detailed Description

Spinal anesthesia is a potent anesthetic procedure and is widely used as it has a number of advantages compared to general anesthesia especially in the geriatric population. It is used for both emergency and elective surgeries and involves the injection of a local anesthetic agent into the cerebrospinal fluid, thereby blocking nerve transmission . Regional anesthesia has been suggested as an alternative to general anesthesia in order to evade or decrease general anesthetic exposure . Neuraxial anesthesia offers numerous benefits as it minimizes the surgical stress, reduces the pulmonary compromise (atelectasis, prolonged mechanical ventilation), provides a superior postoperative pain control and reduction of perioperative opioids consumption, hence minimizing opioid side effects. Neuraxial anesthesia results in better peripheral vascular circulation and reduces total blood loss. Finding adjuvants for spinal anesthesia in geriatric patients is crucial because it allows for the use of lower doses of local anesthetics, which helps minimize potential side effects like hypotension and respiratory depression, while still providing effective pain relief during and after surgery. Adjuvants can also improve the quality and duration of the block, leading to better patient outcomes and faster recovery. Hyperbaric bupivacaine 0.5% is widely used in spinal anesthesia. Main disadvantage of spinal anesthesia with bupivacaine 0.5% is it won't prolong duration of post-operative analgesia . Therefore, research for a drug that may decrease the severity of post-operative pain with minimal side effects seems mandatory. A number of adjuvants have been used to improve post-operative analgesia, along with the bupivacaine. These are opioids, epinephrine, clonidine, dexmedetomidine, midazolam, neostigmine and ketamine . While no study to date has directly assessed the effect of intravenous ketamine infusion on two-segment sensory regression time under spinal anesthesia in elderly patients, related literature provides strong indirect support. For instance, Kathirvel et al. (2000) compared intravenous ketamine versus dexmedetomidine as adjuvants to bupivacaine for spinal anesthesia and reported on onset and duration of sensory and motor block, though not specifically two-segment regression Moreover, a recent 2024 meta-analysis found that ketamine added to regional anesthetic techniques significantly prolongs sensory block by an average of 29.1 minutes. While these studies do not exactly mirror our protocol, they support the hypothesis that IV ketamine may enhance block duration. This underscores the novelty and importance of the current trial, which directly evaluates two-segment regression in a geriatric population undergoing lower-limb surgery.

Ketamine, an N-methyl-D-aspartate (NMDA) receptor blocker, has an anesthetic effect and is synergic with bupivacaine . Its beneficial effects on the cardiovascular system and respiratory functions may be combined with the analgesic effects of spinal anesthesia. Ketamine's impact on cognitive function is largely attributed to its noncompetitive antagonism of NMDA receptors, which disrupts excitatory glutamatergic neurotransmission. Additionally, ketamine increases dopamine release in the prefrontal cortex, which contributes to its psychotomimetic effects such as hallucinations or perceptual disturbances. On the other hand, subanesthetic doses of ketamine have been shown to exert anti-inflammatory and neuroprotective properties, particularly by inhibiting microglial activation and reducing pro inflammatory cytokines implicated in postoperative cognitive dysfunction (POCD). These dual and dose-dependent mechanisms highlight why ketamine may induce cognitive disturbances in some elderly patients while potentially protecting against neuroinflammation-induced cognitive decline in others.

• Study Type: Interventional
• Enrollment (Estimated): 61
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Giza Governorate
    • Cairo, Giza Governorate, Egypt
      • Recruiting
      • Cairo University Hospitals
      • Contact: Mai Younes, MD; Phone Number: 01002309065; Email: younesmai555@gmail.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients aged 65 years and older

  • Both sexes
  • American Society of Anesthesiologists (ASA) physical status I, II, III
  • Scheduled for elective lower limb surgeries under spinal anesthesia in supine position

Exclusion Criteria:

• Patient's refusal.

  • Pre-existing neurological disorders.
  • Coagulopathy (i.e., Platelets ≤ 60,000 and/or INR> 1.5).
  • Localized infection at the site of needle insertion.
  • Known hypersensitivity or allergies to any of the used drugs

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: ketamine group; Patients will receive 0.2 mg/kg IV of ketamine diluted to 5 ml followed by infusion 0.1 mg/kg/hr as a 20 ml solution.	Drug: Patients will receive 0.2 mg/kg IV of ketamine diluted to 5 ml followed by infusion 0.1 mg/kg/hr as a 20 ml solution; Patients will receive 0.2 mg/kg IV of ketamine diluted to 5 ml followed by infusion 0.1 mg/kg/hr as a 20 ml solution
Placebo Comparator: saline group; Patients will receive 5 ml of saline followed by infusion 0.1 ml/kg/hr as a 20 ml solution as a control group	Drug: Patients will receive 5 ml of saline followed by infusion 0.1 ml/kg/hr as a 20 ml solution as a control group; Patients will receive 5 ml of saline followed by infusion 0.1 ml/kg/hr as a 20 ml solution as a control group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of 2-segment regression time.	Duration of 2-segment regression time (defined as time per minutes needed for recovery of sensory block by two segments from the highest sensory level achieved in that patient) using pinprick method.	post delivery of spinal block during intraoperative time

Secondary Outcome Measures

Outcome Measure	Time Frame
Total Duration of sensory block (defined as time per minutes beginning from the intrathecal injection of the drug, to recovery of patient's sensation at S2 dermatome bilaterally) using pinprick method.	Intraoprtative period after delivery of spinal block
Duration of motor block (defined as time per minutes to reach a modified Bromage score of 0)	1st 24 hours after spinal block
Duration of spinal analgesia (time per minutes to the first request for the rescue analgesia)	1st 24 hours post spinal block

Collaborators and Investigators

• Sponsor: Cairo University

Study record dates

Study Major Dates

• Study Start (Actual): April 25, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: April 3, 2026
• First Submitted That Met QC Criteria: April 3, 2026
• First Posted (Actual): April 9, 2026

Study Record Updates

• Last Update Posted (Actual): April 30, 2026
• Last Update Submitted That Met QC Criteria: April 26, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: aging; ketamine; dermatome; spinal block
• Additional Relevant MeSH Terms: Pharmaceutical Preparations; Solutions
• Other Study ID Numbers: IV Ketamine with spinal block

Drug and device information, study documents

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