Does patient-controlled analgesia have benefits over an epidural? Plus CKD research

A large multicenter randomized controlled trial has tested the hypothesis that a potent, ultra-short-acting synthetic opioid might provide pain relief equivalent to that for an epidural. But the results-the first from a well-powered study in this area-suggest caution in use of a patient-controlled form of analgesia perceived to be safe but with significant side effects.

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Researchers performed the trial at 15 hospitals in the Netherlands, enrolling 1414 women with intermediate to high obstetric risk who had the intention of delivering vaginally. The participants were randomized to either patient-controlled remifentanil (n = 709) or epidural analgesia (n = 705) if they requested pain relief during labor. Baseline characteristics were comparable across both groups. Satisfaction with pain relief was expressed as area under the curve (AUC), with higher AUC equaling more satisfaction with pain relief.

Pain relief was requested by 65% of the remifentanil group and 52% of the epidural analgesia group (relative risk 1.32, 95% confidence interval 1.18 to 1.48) with cross over in 7% and 8%, respectively. In the remifentanil group, 13% were converted to epidural analgesia, while 1% in the epidural anesthesia group converted to remifentanil. The AUC for total satisfaction with pain relief in the remifentanil group was 30.9 versus 33.7 in the epidural analgesia group. The rate of cesarean delivery was 15% in both groups.

Oxygen saturation was lower in the remifentanil group (relative risk 1.5, 1.4 to 1.7), at <92% in 18% and <95% in 38% versus 5% and 12% of the epidural group. Four women in the remifentanil group also had respiratory depressions <8 breaths a minute, versus none who received epidurals. Duration of the second stage of labor was significantly shorter with remifentanil versus epidural (median duration 25, interquartile range 11-51 versus 34, 15-60; P=0.01)

Researchers considered the main weakness of the study to be the number of missing values for satisfaction with pain relief and pain intensity. The AUC for pain relief satisfaction during active labor was 57% in the remifentanil group and 43% in the epidural group. Among those who did receive pain relief, the AUCs were 71% and 57% respectively. The researchers also performed a similar study on women who were considered low-risk and the data for that population are currently being analyzed.

Mild kidney disease may increase risk of adverse pregnancy outcomes

Chronic kidney disease (CKD), even when in the early stages, may increase some risks during pregnancy, according to a new prospective study.

Researchers reporting on the Torino-Cagliari Observational Study compared the pregnancy outcomes of 504 pregnancies in women with CKD to 836 low-risk pregnancies in women who did not have CKD. Hypertension, systemic disease, proteinuria (>1 g/d), and CKD stage were assessed at the study’s baseline. Outcomes observed included cesarean delivery, early preterm deliver, and preterm delivery; small for gestational age (SGA); need for the neonatal intensive care unit (NICU), new onset/doubling of proteinuria; CKD shift stage; a “general” combined outcome (NICU, SGA, and preterm delivery); and a “severe” combined outcome (SGA, NICU, and early preterm delivery).

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Across disease stages, the risks of adverse outcomes increased (for stage 1 versus stages 4–5: “general” combined outcome, 34.1% versus 90.0%; “severe” combined outcome, 21.4% versus 80.0%; P<0.001). With stage 1 CKD, preterm delivery was associated with proteinuria (odds ratio [OR], 3.69; 95% confidence interval [CI], 1.63 to 8.36), baseline hypertension (OR, 3.42; 95% CI, 1.87 to 6.21), and systemic disease (OR, 3.13; 95% CI, 1.51 to 6.50). Stage 1 CKD was associated with general combined outcome in women who did not have proteinuria, systemic disease, and baseline hypertension (OR, 1.88; 95% CI, 1.27 to 2.79). Risk of intrauterine death was unchanged between the control group and the patient group.

Investigators concluded that the prospective study seems to indicate that a “baseline risk” exists for adverse pregnancy outcomes in women who have CKD.