Analgesic Low-Dose Ketamine Infusions and Central Nervous System Adverse Effects: A Prospective Cohort Study

Area of Science:

• Anesthesiology and Pain Management
• Pharmacology
• Neuroscience

Background:

• Low dose ketamine infusions (LDKI) show potential for adjuvant analgesia and reduced opioid use in specific patient groups.
• Limited data exists on central nervous system (CNS) adverse effects of LDKI for postoperative pain management.

Purpose of the Study:

• To compare the incidence of CNS adverse effects in patients receiving LDKI versus those not receiving ketamine within 48 hours post-surgery.
• To evaluate the safety and efficacy of LDKI as part of multimodal analgesia.

Main Methods:

• Unicentric prospective cohort comparative study at an academic university hospital.
• 101 patients received LDKI (0.1 mg/kg/h) as part of multimodal analgesia; 138 did not.
• Primary outcome: composite of CNS adverse effects (delirium, hallucinations, nightmares); Secondary outcomes: pain intensity, cardiovascular variables.

Main Results:

• No significant differences in delirium, agitation, or sedation between groups.
• The composite incidence of CNS symptoms was higher in the LDKI group (12.9% vs 2.2%).
• Higher incidence of nightmares (8.9% vs 0.72%) and hallucinations (6.8% vs 2.2%) in the LDKI group. Pain intensity was significantly lower in the LDKI group (P=0.03).

Conclusions:

• LDKI (0.1 mg/kg/h) is associated with a low incidence of minor CNS effects like nightmares and hallucinations.
• No significant association with major CNS adverse effects (delirium, sedation, agitation) was found.
• LDKI appears safe as an adjuvant in multimodal analgesia for postoperative pain management.