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Spinal Hydromorphone Versus Morphine for Post-Cesarean Delivery Analgesia

Phase 4
Completed
Conditions
Postoperative Pain
Interventions
Registration Number
NCT03592992
Lead Sponsor
Lawson Health Research Institute
Brief Summary

Morphine is usually used for pain relief after cesarean delivery. However, sometimes it is not available, the patient might be allergic to morphine or intolerant to its side effects. Hydromorphone, another drug from the same class, might be used alternatively, but we need to prove that it is not inferior to morphine.

Detailed Description

Spinal or intrathecal (IT) morphine is the most commonly used opioid for post-cesarean delivery analgesia. Factors that contribute to its widespread use include a favorable pharmacokinetic profile with duration of action up to 24 hours, ease of administration (during spinal block for surgical anesthesia) and low cost. Most providers administer 100 to 200 mcg of IT morphine for cesarean delivery analgesia with excellent analgesic results. Nevertheless, subarachnoid use of morphine is not without adverse events. While dose-dependent respiratory depression is the most worrisome complication, other side effects such as pruritus, nausea, vomiting and urinary retention can be bothersome during early puerperium. Furthermore, shortages of preservative free morphine in the United States has led clinicians to seek a reasonable alternative.

For the last 20 years, spinal hydromorphone has been successfully used for chronic pain associated with neoplasms. Its use for post-cesarean analgesia has been successfully reported. However, data regarding its efficacy in the IT space for post-cesarean analgesia is scarce. In the past, doses of 40 to 100 mcg have been reported to provide adequate postoperative pain relief with minimal side effects. In a recent study, the Effective Dose in 90% of patients has been established for both Hydromorphone and Morphine to be 75 mcg and 150 mcg, respectively.

No prospective studies have been conducted to specifically establish non-inferiority of hydromorphone when compared to morphine for post- cesarean analgesia. In addition, while all opioids share the same side effect profile, the frequency of those events are unknown for IT hydromorphone.

The current proposal is a blinded randomized controlled trial of intrathecal hydromorphone versus morphine in term pregnant women undergoing elective cesarean deliveries under spinal anesthesia.

Recruitment & Eligibility

Status
COMPLETED
Sex
Female
Target Recruitment
126
Inclusion Criteria
  • Age > 18 years; American Society of Anesthesiologist's Physical Status (ASA-PS) < 3; Term pregnancy (> 37 weeks gestational age); Elective cesarean delivery; Spinal Anesthesia;
Exclusion Criteria
  • Documented allergy or severe intolerance to opioids; Intra-operative conversion to a general anesthetic technique; Chronic pain syndrome with baseline pain levels >3 on a visual analogue scale (0-10 cm); History of opioid use during this pregnancy; Allergy or intolerance to NSAIDS or acetaminophen; Morbid obesity- Body Mass Index (BMI) >40.

Study & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
Spinal HydromorphoneSpinal HydromorphoneFor the intervention group, 75 mcg of hydromorphone will be added to the spinal anesthetic mixture as a one-time injection prior to cesarean delivery.
Spinal MorphineSpinal MorphineFor the control group,150 mcg of preservative-free morphine will be added to the spinal anesthetic mixture as a one-time injection prior to cesarean delivery.
Primary Outcome Measures
NameTimeMethod
Difference in the Average Numeric Rating Score (0-10 , where 0=no pain and 10= maximum pain) during the first 24 hours.24 hours after spinal anesthesia.

This is defined as the between- group difference in the average pain scores on a 0-10 Numeric Rating Scale, as assessed by a nurse, anesthesia consultant or trainee 24 hours after spinal anesthesia.

Secondary Outcome Measures
NameTimeMethod
Difference in NRS pain scores at specific time points in the first 24 hours.immediately after surgery (in PACU), 6, 12 and 18 hours after spinal anesthesia is given.

This is defined as the between- group difference in the mean pain scores on a 0-10 Numeric Rating Scale, as assessed by a nurse, anesthesia consultant or trainee immediately after surgery (in the Post-Anesthesia Care Unit) and at 6, 12, 18 and 24 hours after spinal anesthesia.

Time-to-first oral opioid analgesic requestMeasured in hours from the time of spinal anesthetic until patient request for prescribed oral opioid analgesia, up to 24 hours from the spinal anesthetic .

This is defined as the length of time between spinal anesthesia and the first time the subject requested additional opioid analgesia, up to 24 hours from the spinal anesthesia.

Nausea and/or Vomiting that required treatment.Absolute number of treatments required in the 24-hour time frame.

Nausea/Vomiting episodes that required pharmacological treatment in the first 24 hours after spinal anesthesia

Pruritus that required treatment.Absolute number of treatments required in the 24-hour time frame.

Pruritus episodes that required pharmacological treatment in the first 24 hours after spinal anesthesia

Respiratory DepressionIn post-anesthesia care unit (PACU), 6, 12, 18 and 24 hours after spinal anesthesia

Respiratory Rate measured in breaths/minute)

Apgar Scores1 and 5 minutes after birth.

Neonatal Apgar scores at 1 and 5 minutes in a 1-10 interval scale

Difference in Opioid Consumption in the first 24 hours24 hours after spinal anesthesia.

This is defined as the between-group difference in the total amount of Oral Morphine Equivalents consumed in the first 24 hours after spinal anesthesia is given.

Obstetric Quality of Recovery Score ObsQoR-1124 hours after spinal anesthesia.

11-item questionnaire applied to subjects 24 hours after spinal anesthesia. Measured in a 0-110 scale

Trial Locations

Locations (1)

Victoria Hospital- LHSC

🇨🇦

London, Ontario, Canada

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