Incidence and influential factors of postoperative pruritus in morphine-based intravenous patient-controlled analgesia

Chung-Yi Liao; Hsiang-Ling Wu; Yu-Ming Wu; Juan P Cata; Jui-Tai Chen; Chien-Wun Wang; Yih-Giun Cherng; Ying-Hsuan Tai

doi:10.1097/JCMA.0000000000001180

Incidence and influential factors of postoperative pruritus in morphine-based intravenous patient-controlled analgesia

J Chin Med Assoc. 2024 Oct 15. doi: 10.1097/JCMA.0000000000001180. Online ahead of print.

Authors

Chung-Yi Liao^{1

2}, Hsiang-Ling Wu^{3

4}, Yu-Ming Wu^{1

2}, Juan P Cata⁵, Jui-Tai Chen^{1

2}, Chien-Wun Wang^{1

2}, Yih-Giun Cherng^{1

2}, Ying-Hsuan Tai^{1

2}

Affiliations

¹ Department of Anesthesiology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan, ROC.
² Department of Anesthesiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, ROC.
³ Department of Anesthesiology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.
⁴ School of Medicine, National Yang Ming Chiao Tung University, Taipei1, Taiwan, ROC.
⁵ Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 409, Houston, USA.

PMID: 39787467
DOI: 10.1097/JCMA.0000000000001180

Abstract

Background: Pruritus is a distressing symptom of systemic opioid analgesia that responds poorly to conventional antipruritus treatments. This study aimed to determine the incidence and risk factors for postoperative pruritus using intravenous patient-controlled analgesia (IV-PCA).

Methods: Opioid-naïve patients who underwent morphine-based IV-PCA for postoperative pain at a tertiary center between January 1, 2020, and June 30, 2023, were included retrospectively. The primary outcome was pruritus within 72 h after surgery. Cumulative morphine consumption and pain numerical rating scores were measured to evaluate the potential impact of pruritus on postoperative pain control.

Results: A total of 1,696 patients were enrolled, of whom 119 (7.0%) developed pruritus during the study period. Five independent factors for pruritus were identified, including intraoperative uses of hydroxyethyl starch solutions [adjusted odds ratio (aOR): 0.13, 95% confidence interval (CI): 0.04-0.43], lockout interval of IV-PCA (aOR: 0.50, 95% CI: 0.27-0.94, on base-2 logarithmic scale), droperidol addition to morphine solutions (aOR: 0.53, 95% CI: 0.35-0.81), cumulative morphine dose (aOR: 1.76, 95% CI: 1.47-2.12, on base-2 logarithmic scale), and postoperative uses of antihistamines (aOR: 2.90, 95% CI: 1.83-4.60) (c-statistic = 0.745). Patients with pruritus had higher postoperative morphine consumption (median: 67.5 mg, interquartile range: 38.3-94.0 vs. 38.0 mg, 21.0-65.4, p<0.0001) but similar pain intensity compared to those without pruritus.

Conclusion: Increasing the lockout interval and the droperidol regimen may protect patients from morphine-induced pruritus after IV-PCA. Further studies are warranted to clarify the mechanisms underlying the anti-pruritus effects of hydroxyethyl starch.