Respiratory compromise after MgSO4 therapy for preterm labor in a woman with myotonic dystrophy: a case report

BACKGROUND

MgSO4 is widely used for tocolysis. Serious complications are rare as long as dosing is carefully monitored. Adverse effects in muotonic dustrophy have not been previously described.

CASE

A 35-year-old woman, gravida 1, para 0, was hospitalized with suspected mild myotonic dystrophy, polyhydramnios and preterm labor at 33 weeks. MgSO4 infusion rapidly resulted in respiratory compromise. Muscular strength returned to baseline after the infusion was stopped. Mother and infant proved to have myotonic dystrophy.

CONCLUSION

The choice of tocolytic medication in maternal myotonic dystrophy is problematic. Beta-2 sympathomimetics have been reported to precipitate myotonia. This case illustrates the potential for MgSO4 to cause respiratory embarrassment. Indomethacin may be the tocolytic of choice in myotonic dystrophy.

A comparison of Depodur, a novel, single-dose extended-release epidural morphine, with standard epidural morphine for pain relief after lower abdominal surgery

In this randomized, controlled, dose-ranging study, we evaluated the analgesic efficacy of a novel single-dose extended-release epidural morphine (Depodur) in patients undergoing lower abdominal surgery. Five-hundred-forty-one patients were randomly assigned to one of six epidural treatments administered approximately 30 min before surgery. The 6 treatments were 5 mg of standard epidural morphine sulfate (MS) (active comparator); 5 mg of single-dose extended-release epidural morphine (EREM) (dose control); and 10, 15, 20, and 25 mg of single-dose EREM. The main study objective was to assess the efficacy of single-dose EREM 10, 15, 20, or 25 mg versus single-dose EREM 5 mg for the management of postoperative pain. This was done by plotting a linear dose-response relationship to assess postoperative IV patient-controlled analgesia (PCA) fentanyl consumption for breakthrough pain for 48 h after surgery. Secondary safety and efficacy analyses compared the 10-, 15-, 20-, and 25-mg single-dose EREM groups with the 5-mg single-dose EREM group and compared each single-dose EREM group with 5 mg of MS. As shown by the dose-response relationship, there was a dose-related reduction in the use of postoperative IV fentanyl through 48 h (estimated slope, -22.2; P = 0.0002). Patients treated with 10, 20, and 25 mg of single-dose EREM used significantly less IV fentanyl (mean +/- sd: 995 +/- 987 microg, P = 0.0446; 972 +/- 982 microg, P = 0.0221; and 683 +/- 620 microg, P < 0.0001, respectively) through 48 h after surgery compared with the 5-mg single-dose EREM group (1218 +/- 894 microg). At 48 h postdose, significantly more single-dose EREM patients (13%) than MS patients (2%) had required no IV fentanyl (P < 0.01). Although all treatment groups had access to PCA fentanyl and there was more frequent PCA fentanyl use in the MS group, patients in the single-dose EREM 15, 20, and 25 mg groups reported significantly lower pain-intensity scores and greater satisfaction with their pain relief. Overall, single-dose EREM was well tolerated, with 97% of adverse events rated as mild to moderate. As expected, the adverse events reported were consistent with those of other epidural opioids (i.e., nausea, vomiting, pruritus, and hypotension). In conclusion, this controlled study demonstrated that single-dose EREM can provide up to 48 h of postoperative analgesia, but supplementation for breakthrough pain is still required in most patients. Within the context of this study, the side effect profile of single-dose EREM was acceptable and predictable.

Single-dose, sustained-release epidural morphine in the management of postoperative pain after elective cesarean delivery: results of a multicenter randomized controlled study

In this multicenter, randomized, controlled study, we compared the analgesic efficacy and safety profile of a new single-dose extended-release epidural morphine (EREM) formulation (DepoDur) with that of epidural morphine sulfate for the management of postoperative pain for up to 48 h after elective cesarean delivery. ASA physical status I or II parturients (n = 75) were anesthetized with a combined spinal/epidural technique. Parturients received intrathecal bupivacaine 12-15 mg and fentanyl 10 mug for spinal anesthesia and a single epidural injection of either 5 mg of standard (conventional preservative-free) morphine or 5, 10, or 15 mg of extended-release morphine after cord clamping for postoperative pain control. Single-dose EREM 10 and 15 mg groups significantly decreased total supplemental opioid medication use and improved functional ability scores for 48 h after surgery compared with those receiving 5 mg of standard morphine. Visual analog scale pain scores at rest and with activity at 24 to 48 h after dosing were significantly better in the 10- and 15-mg single-dose EREM groups versus the standard morphine group. There were no significant differences between the two 5 mg (single-dose EREM and standard morphine) groups. Single-dose EREM was well tolerated, and most adverse events were mild to moderate in severity. Single-dose EREM is a potentially beneficial epidural analgesic for the management of post-cesarean delivery pain and has particular advantages over standard morphine for the period from 24 to 48 h after surgery.

Double-blind comparison of epidural ropivacaine 0.25% and bupivacaine 0.25%, for the relief of childbirth pain

PURPOSE

To evaluate the efficacy of ropivacaine 0.25% when administered epidurally for relief of labour pain and to compare it with bupivacaine 0.25%.

METHODS

In a multicentre investigation, 60 ASA I and II labouring women were randomized in a double-blind fashion to receive either bupivacaine 0.25% or ropivacaine 0.25% administered epidurally by intermittent top-up for labour analgesia. Using a standardized technique, epidural analgesia was initiated after the woman received 10-15 ml-kg.1 crystalloid solution. Maternal blood pressure, heart rate, analgesia sensory level, degree of motor block and visual analogue pain scores were measured by the research nurse prior to, and at regular intervals, following the administration of analgesia. Total dose of local anaesthetic administered, duration of labour, mode of delivery, and maternal and fetal/neonatal side effects were noted. The fetus/neonate was assessed by the research nurse using the fetal heart rate tracing, Apgar scores at delivery and neonatal neurobehavioural assessments at 2 and 24 hr postnatally. Maternal and investigators' satisfaction with the analgesia achieved was assessed after delivery.

RESULTS

No differences were found between the two agents in any of the variables studied.

CONCLUSION

Ropivacaine 0.25%, when administered epidurally by intermittent top-ups for labour analgesia, was equally efficacious as bupivacaine 0.25%.

Effect of preoperative skin infiltration with 0.5% bupivacaine on postoperative pain following cesarean section under spinal anesthesia

Recent work suggests that preoperative skin infiltration with local anesthetic may lead to reduced postoperative pain. We have studied this in a randomised, prospective, double-blind trial of 40 women having cesarean section under spinal anesthesia. After establishment of the spinal block, the incision line was infiltrated in 20 women with 30 ml 0.5% bupivacaine and in 20 with 30 ml normal saline. There was no difference in pain scores between the 2 groups on any of the 3 postoperative days, perhaps due to the high quality analgesia provided by supplemental subarachnoid morphine.