Labor Pain
Conditions
Keywords
Obstetric anesthesia, labor analgesia, morphine, epidural analgesia
Brief summary
The purpose of this study is to determine the ideal dosage of intrathecal morphine for intra and post partum analgesia, while minimizing the side effect profile.
Detailed description
Regional anesthesia techniques such as combined spinal epidural (CSE) analgesia are very effective for the management of intrapartum pain. The advantages of these techniques are that they are safe when properly conducted and that they provide excellent analgesia while allowing the patient to remain awake and participate in the labor and delivery. The risks of maternal aspiration and fetal drug depression associated with general anesthesia are minimized. Finally, the effective analgesia associated with regional techniques blunt the hemodynamic effects caused by painful contractions and reduce maternal catecholamines, resulting in increased placental perfusion.1 Opioids in combination with local anesthetics in the spinal space provide effective pain relief during labor with minimal side effects. The advantages of spinal opioid administration include lack of motor blockade and faster onset of analgesia.2 In addition, since the opiate receptors are in the spinal space, a smaller amount of opioid can be used to provide excellent pain relief while minimizing the side effects. At Beth Israel Deaconess Medical Center (BIDMC), the obstetric anesthesiology group uses a standard spinal dosing for CSE during labor which includes: 1 ml of 0.25% bupivicaine with 12.5 mcg of fentanyl. Yeh and colleagues have found that morphine 150 mcg added to the fentanyl-bupivicaine spinal injection can prolong the duration of spinal analgesia but was associated with increased side effects. 3 The side effect profile of spinal narcotics include: nausea, vomiting, pruritus, and urinary retention. Although these side effects for the most part can be easily treated, they can be bothersome to the post partum patient. In a previous study performed from our institution, the addition of 100 mcg of morphine to spinal bupivicaine and fentanyl reduced the rate of breakthrough pain during labor analgesia and prolonged the time to first request for supplementation. Overall, it was found that the incidence of side effects was low but the group that received the spinal morphine did have more nausea and vomiting compared with the placebo group. 4 In this current investigation, we would like to assess whether an even smaller dose of spinal morphine would provide an effective, pain free recovery from vaginal delivery while decreasing the incidence of side effects, specifically nausea and vomiting. We would like to perform a formal dose response study to identify the ideal dose of intrathecal morphine that would not compromise the pain relief during labor while minimizing the side effects.
Interventions
DRUGMorphine
Active dosage
DRUGSaline
Saline Control
Sponsors
Beth Israel Deaconess Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 50 Years
Healthy volunteers
No
Inclusion criteria
* singleton pregnancy, * at least 36 weeks gestational age, * active labor (≤ 5 cm dilation) requesting neuraxial analgesia, * ASA I or II, * not currently taking pain medications.
Exclusion criteria
* multiple gestation, * preterm labor, * systemic opioids in the past 4 hours, * chronic pain syndromes, * chronic opioid use, * contraindications to regional anesthesia, * allergies to opioids, * significant co existing medical problems, * severe pregnancy induced hypertension, * sedatives, * magnesium therapy, * diabetes type 1.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Rate of Breakthrough Pain | Participants were followed for the duration of delivery, an average of 7 hours | Rate of breakthrough pain is the number of episodes of breakthrough pain divided by the number of hours of labor. Time measured from placement of the neuraxial anesthetic, until delivery of the neonate. Because duration of labor is different for all patients, the rate of breakthrough pain per hour is used as the primary outcome. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Placebo Saline control | 19 |
| Morphine 25 Morphine 25 micrograms | 17 |
| Morphine 50 Morphine 50 micrograms | 21 |
| Hine 75 Morphine 75 micrograms | 13 |
| Morphine 100 Morphine 100 micrograms | 13 |
| Total | 83 |
Baseline characteristics
| Characteristic | Morphine 25 | Placebo | Morphine 50 | Hine 75 | Morphine 100 | Total |
|---|---|---|---|---|---|---|
| Age, Continuous | 31.5 Years STANDARD_DEVIATION 5.3 | 34.3 Years STANDARD_DEVIATION 5.3 | 31.3 Years STANDARD_DEVIATION 6.6 | 32.5 Years STANDARD_DEVIATION 5.5 | 32.4 Years STANDARD_DEVIATION 5.7 | 32.3 Years STANDARD_DEVIATION 5.7 |
| Sex: Female, Male Female | 17 Participants | 19 Participants | 21 Participants | 13 Participants | 13 Participants | 83 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk |
|---|---|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — | — / — | — / — |
| other Total, other adverse events | 0 / 19 | 0 / 17 | 0 / 21 | 0 / 13 | 0 / 13 |
| serious Total, serious adverse events | 0 / 19 | 0 / 17 | 0 / 21 | 0 / 13 | 0 / 13 |
Outcome results
Primary
Rate of Breakthrough Pain
Rate of breakthrough pain is the number of episodes of breakthrough pain divided by the number of hours of labor. Time measured from placement of the neuraxial anesthetic, until delivery of the neonate. Because duration of labor is different for all patients, the rate of breakthrough pain per hour is used as the primary outcome.
Time frame: Participants were followed for the duration of delivery, an average of 7 hours
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Control | Rate of Breakthrough Pain | 0.25 episodes of breakthrough pain per hour | Standard Deviation 0.29 |
| Morphine 25 | Rate of Breakthrough Pain | 0.28 episodes of breakthrough pain per hour | Standard Deviation 0.35 |
| Morphine 50 | Rate of Breakthrough Pain | 0.25 episodes of breakthrough pain per hour | Standard Deviation 0.25 |
| Morphine 75 | Rate of Breakthrough Pain | 0.23 episodes of breakthrough pain per hour | Standard Deviation 0.26 |
| Morphine 100 | Rate of Breakthrough Pain | 0.17 episodes of breakthrough pain per hour | Standard Deviation 0.21 |