{
  "abstract": "Purpose\n\nVisceral traction during cesarean delivery may cause pain, nausea, and autonomic activation despite an adequate neuraxial block. We evaluated whether adding 0.3 mg epidural hydromorphone to ropivacaine altered patient-reported pain and clinically relevant traction responses across predefined perioperative phases.Patients and methods\n\nIn this single-center, double-blind, placebo-controlled trial, 96 women undergoing elective cesarean delivery were randomized 1:1 to epidural hydromorphone or saline. The registered primary outcome domains were visual analog scale (VAS) pain score and heart rate variability (HRV) across five time points. Other prespecified clinical measures included clinician-rated traction response, maternal adverse events, and neonatal outcomes. The protocol-specified repeated-measures analysis was used for longitudinal pain; abdominal exploration (T2) was selected after registration as the focal phase for detailed reporting.Results\n\nAll 96 women completed the trial. The longitudinal pain analysis showed a group-by-time interaction (Greenhouse-Geisser corrected p=0.008; participant-level randomization-based permutation p=0.009). At the post-registration focal comparison during abdominal exploration, median (IQR) VAS was 1.65 (0.70-2.60) with hydromorphone and 1.90 (0.78-3.92) with saline (nominal Mann-Whitney p=0.039). Clinician-rated traction grade favored hydromorphone (trend p=0.003). Nausea or vomiting occurred in 3/48 (6.2%) versus 12/48 (25.0%) women (risk ratio 0.25, 95% CI 0.08-0.83; p=0.022). For the registered HRV domain, the interaction for ln(LF/HF), selected after registration as the principal reported metric, was not significant (p=0.442). No maternal respiratory depression occurred, and neonatal outcomes showed no material between-group differences.Conclusion\n\nLow-dose epidural hydromorphone added to ropivacaine was associated with a different longitudinal pain profile and fewer episodes of intraoperative nausea or vomiting during elective cesarean delivery. Post hoc pain-distribution and exploratory physiological findings require prospective confirmation.Trial registration\n\nChinese Clinical Trial Registry, ChiCTR2400094749; registered December 26, 2024, before enrollment.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Anesthesiology, Chongqing Wanzhou Health Center for Women and Children, Chongqing, People's Republic of China."
  ],
  "article_type": "case report",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Yi Zhang",
      "orcid": "0009-0009-1853-9358"
    },
    {
      "affs": [
        0
      ],
      "name": "Qingjun Zeng"
    },
    {
      "affs": [
        0
      ],
      "name": "Haishan Cui"
    },
    {
      "affs": [
        0
      ],
      "name": "Chunmei Li"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/epry3bk5ghjw7.bib",
  "cited_by": 0,
  "doi": "10.2147/dddt.s649481",
  "fulltext_url": "https://europepmc.org/articles/PMC13712146",
  "id": "epry3bk5ghjw7",
  "issns": [
    "1177-8881"
  ],
  "landing_url": "https://europepmc.org/article/MED/42948659",
  "language": "eng",
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Clinical Trial Report"
    ],
    [
      "openalex",
      "2746|Anesthesia and Pain Management"
    ]
  ],
  "openalex": "W7223345309",
  "pdf_url": "https://europepmc.org/articles/PMC13712146?pdf=render",
  "pmcid": "PMC13712146",
  "pmid": "42948659",
  "published": "2026-10-23",
  "publisher": "Dove Press",
  "ris": "https://research.draconitic.com/paper/epry3bk5ghjw7.ris",
  "sources": [
    {
      "first_seen": "2026-10-31T00:20:34Z",
      "native_id": "MED:42948659",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42948659"
    },
    {
      "first_seen": "2026-10-31T12:22:47Z",
      "native_id": "PMC13712146",
      "source": "pmc",
      "url": "https://doi.org/10.2147/dddt.s649481"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2746|Anesthesia and Pain Management",
      "subfield": "surgery"
    }
  ],
  "title": "Low-Dose Epidural Hydromorphone as an Adjunct to Ropivacaine for Intraoperative Visceral Traction Pain During Elective Cesarean Delivery: A Randomized, Double-Blind, Placebo-Controlled Trial.",
  "title_text": "Low-Dose Epidural Hydromorphone as an Adjunct to Ropivacaine for Intraoperative Visceral Traction Pain During Elective Cesarean Delivery: A Randomized, Double-Blind, Placebo-Controlled Trial.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-31T12:22:47Z",
  "url": "https://research.draconitic.com/paper/epry3bk5ghjw7",
  "venue": "Drug design, development and therapy",
  "versions": []
}