Ketamine for Preventing Chronic Postsurgical Pain after Thoracic Surgery

Abstract

Introduction: Chronic postsurgical pain affects 30-50% of patients after thoracotomy or video-assisted thoracic surgery. This review evaluates ketamine’s role in reducing chronic pain development through N-methyl-D-aspartate receptor antagonism.

Methods: A literature search identified randomized controlled trials of perioperative ketamine versus placebo or standard analgesia in adults undergoing thoracic surgery. Chronic pain was defined as pain persisting ≥3 months postoperatively at the surgical site. Primary outcome was chronic pain incidence. Secondary outcomes included acute pain scores and opioid consumption.

Results: Eight trials with 1,124 patients were included. Ketamine reduced chronic pain incidence at three months by 38% (relative risk 0.62). The effect was more pronounced in trials using intraoperative ketamine infusion plus postoperative continuation for 48 hours. Acute pain scores at 24 hours were modestly lower with ketamine, and cumulative opioid consumption decreased by 32%. Psychotomimetic adverse effects occurred in 8% of ketamine recipients but did not require treatment discontinuation.

Discussion: Ketamine likely prevents central sensitization by blocking spinal and supraspinal N-methyl-D-aspartate receptors during the nociceptive barrage of thoracic surgery. Heterogeneity in dosing regimens (0.2 to 0.5 mg/kg bolus followed by 2 to 5 μg/kg/min infusion) limits determination of an optimal protocol. Most studies excluded patients with psychiatric disorders or uncontrolled hypertension.

Conclusions: Perioperative ketamine reduces chronic postsurgical pain after thoracic surgery, particularly when continued beyond the intraoperative period. Further research should standardize infusion duration.