687: THE EFFECT OF POST OP KETAMINE NEBULIZATION ON POST OP OPIOID REQUIRMENT IN LAPROSCOPIC SURGERIES

Topic: Experimental (Non-clinical) Human Studies
Subtopic: Pain Category (ICD-11), Acute postsurgical pain, Psychology, Gender/sex differences, Pharmacological treatments

Background and Aims: Postoperative pain following laparoscopic surgery is commonly managed with opioids, which carry significant risks including respiratory depression, apnea, nausea, and dependency. Ketamine, an NMDA receptor antagonist, has emerged as a promising opioid-sparing analgesic. It provides effective pain relief with sedative properties while causing bronchodilation rather than respiratory depression. Nebulized ketamine offers a non-invasive, rapid delivery route with 20–40% bioavailability compared to IV administration, and prior studies have demonstrated up to 50% pain relief without major side effects.
This study aims to assess the efficacy and safety of postoperative nebulized ketamine in reducing opioid consumption during the first 6 hours after general laparoscopic surgery, and to evaluate the duration of analgesia it provides. A randomized comparison between ketamine nebulization (1 mg/kg) and normal saline placebo will be conducted at National Hospital Lahore across 227 patients

Methods: This cross-sectional study will be conducted at the Department of Anesthesia, National Hospital Lahore over 6 months. Using consecutive sampling, 227 patients aged 18–60 years (ASA I–III) undergoing general laparoscopic surgery will be enrolled. Patients with cancer, ASA IV status, ketamine contraindications, or refusal to consent will be excluded. Participants will be divided into two groups: Group A receiving nebulized ketamine (1 mg/kg in 5ml) and Group B receiving normal saline placebo, administered via oxygen-driven nebulization mask for 15 minutes upon arrival in the postoperative ward. Numerical pain scores will be recorded at 0, 2, 4, and 6 hours. Opioid consumption and adverse effects including hallucinations, dizziness, and nausea will be documented. Data will be analyzed using IBM SPSS and R Studio, applying t-tests, Mann-Whitney U, Chi-square, repeated measures ANOVA, and regression models where appropriate.

Results: Preliminary data comparing nebulized (treatment) and non-nebulized (control) groups revealed notable differences in postoperative pain relief timing. In the control group, pain relief peaked at hour 6, with most patients experiencing relief between hours 3–6, indicating delayed analgesia. The treatment group showed a left-skewed distribution, with peak relief at hour 1 and the majority achieving relief within 3 hours. When stratified by opioid type, Tramal and the Fentanyl-Tramal combination paired with nebulization showed faster relief onset, suggesting a potential synergistic effect. Age-based analysis demonstrated consistently earlier pain relief across all age groups in the treatment arm, including patients over 50 years. Even older, more vulnerable patients experienced relief between hours 2–4 with nebulization, compared to delayed responses in controls. These findings suggest nebulized ketamine significantly accelerates postoperative analgesia onset across diverse patient subgroups.

Conclusions: This study provides preliminary evidence that postoperative ketamine nebulization is associated with earlier and more effective pain relief compared to placebo in patients undergoing general laparoscopic surgery. Across all analytical dimensions — treatment status, opioid type, and patient age — the nebulized group consistently achieved faster pain relief onset. Certain opioid combinations, particularly Tramal and Fentanyl-Tramal, appeared to demonstrate synergistic analgesic benefits when paired with ketamine nebulization. The consistent benefit observed across age groups, including older patients, further strengthens the case for nebulized ketamine as a broadly applicable analgesic adjunct. Given ketamine's favorable safety profile — notably the absence of respiratory depression — it represents a valuable opioid-sparing strategy in multimodal postoperative pain management. Larger, statistically powered trials are warranted to confirm causality, establish optimal dosing, and evaluate long-term outcomes, but current findings support integrating nebulized ketamine into standard postoperative care protocols.

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Presenting Author: Dr Minahil Zaman
Submitting Author: Minahil Zaman

Senior Author: Dr Minahil Zaman

IASP 2026 Global Year theme of Neuropathic Pain: Yes