425: Demand-to-Delivery Ratio as a Marker of Early Discontinuation risk in Patient-Controlled Analgesia

Topic: Clinical Science
Subtopic: Pain category (ICD-11), Acute postsurgical pain, Pharmacological treatments, Assessment and Measurement of Pain/Nociception, Treatment/management

Background and Aims: Patient-controlled analgesia (PCA) is widely used for postoperative pain control, yet early discontinuation frequently occurs due to inadequate analgesia or adverse effects. The demand-to-delivery (D/D) ratio reflects the relationship between patient requests and actual opioid delivery and has been proposed as an indicator of PCA adequacy, with an optimal value below 1.35. However, its association with PCA continuation remains unclear. This study aimed to evaluate the distribution characteristics of D/D ratio and examine whether elevated D/D ratio serves as a marker of early PCA discontinuation risk.

Methods: This retrospective study included 294 patients who received intravenous PCA after gastrectomy. Early discontinuation was defined as PCA use for less than 72 hours. The D/D ratio was calculated by dividing total demand attempts by actual delivered doses. Distribution was assessed using mean, median, skewness, and kurtosis. Patients were categorized by quartiles and by the 1.35 cut-off value. Associations with early discontinuation were analyzed using chi-square tests and odds ratios with 95% confidence intervals.

Results: The mean D/D ratio was 1.59 (median 1.25) and demonstrated right-skewed distribution (skewness=2.50). Early discontinuation occurred in 29.3% of patients. In quartile analysis, early discontinuation was highest in the upper quartile (42.5%) compared with lower quartiles (24.9%, p=.004). Patients in the highest quartile had 2.23-fold higher odds of early discontinuation (95% CI 1.28–3.88). Using the 1.35 cut-off, elevated D/D ratio was also significantly associated with increased early discontinuation (p<.05).

Conclusions: Elevated D/D ratio was significantly associated with PCA early discontinuation. Patients in the highest quartile demonstrated more than twofold increased odds of discontinuation. These findings suggest that D/D ratio may function as a clinically meaningful marker of PCA usage patterns and risk stratification. Monitoring high D/D patterns may support individualized postoperative pain management strategies and improve PCA optimization.

References: 1. Macintyre, P. E., Schug, S. A., Scott, D. A., Visser, E. J., & Walker, S. M. (2015). Acute pain management: Scientific evidence (4th ed.). Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine.
2. Grass, J. A. (2005). Patient-controlled analgesia. Anesthesia & Analgesia, 101(5 Suppl), S44–S61. https://doi.org/10.1213/01.ANE.0000177102.96961.4A
3. Hudcova, J., McNicol, E., Quah, C., Lau, J., & Carr, D. B. (2006). Patient-controlled opioid analgesia versus conventional opioid analgesia for postoperative pain. Cochrane Database of Systematic Reviews, (4), CD003348. https://doi.org/10.1002/14651858.CD003348.pub2
4. Motamed, C. (2022). Clinical update on patient-controlled analgesia for acute postoperative pain. Pain Practice, 22(3), 349–359. https://doi.org/10.1111/papr.13103
5. Pastino, A., & Lakra, A. (2023). Patient-controlled analgesia. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK551610/
6. Kim, S., et al. (2023). Risk factors for discontinuation of intravenous patient-controlled analgesia after general surgery. Scientific Reports, 13, Article 45033. https://doi.org/10.1038/s41598-023-45033-2
7. Park, K. N., Ryoo, S. H., Karm, M. H., Kim, H. J., & Seo, K. S. (2025). Analysis of the effect of fentanyl dosage used in patient-controlled analgesia for pain management after oral cancer surgery: A retrospective observational study. Journal of Dental Anesthesia and Pain Medicine, 25(1), 43–53.
8.Dort, J. C., Farwell, D. G., Findlay, M., Huber, G. F., Kerr, P., Shea-Budgell, M. A., ... & Harris, J. R. (2017). Optimal perioperative care in major head and neck cancer surgery with free flap reconstruction: A consensus review. JAMA Otolaryngology–Head & Neck Surgery, 143(3), 292–303. https://doi.org/10.1001/jamaoto.2016.2981

Presenting Author: Seyeon Park
Submitting Author: Seyeon Park

Senior Author: Seyeon Park

IASP 2026 Global Year theme of Neuropathic Pain: No

• Jeungeun Lee - Chungnam National University
• Taehui Kim: MD, PhD - Chungnam National University
• Woolim Min - Chungnam National University
• Eunjin Song - Chungnam National University Hospital
• Boohwi Hong: MD, PhD - Chungnam National University Hospital