Comments on “combination of dexmedetomidine and remifentanil for labor analgesia: A double-blinded, randomized, controlled study”

Epidural analgesia is now the method of choice for the treatment of pain in labor and delivery. However, this technique may be contraindicated, especially in pregnant with coagulation disorders, so we need other analgesic alternatives.[1]

Nonneuraxial pharmacological therapies (peripheral blocks or analgesic administration via intravenous or inhalational routes) and nonpharmacological therapies (relaxation, psychological or mechanical techniques) had been used, but today, remifentanil patient-controlled analgesia (PCA) is the best alternative in patients with contraindication to neuraxial analgesia,[2] although more studies are needed to assess its efficacy and safety.[3]

The authors have studied the combined effects of intravenous remifentanil and dexmedetomidine, and this report with such combination of drugs implies several key points:

• First, obstetrical anesthesia is sometimes a reluctant part of our specialty to change, so new investigations (and alternatives) are welcome, and this report open many possibilities to improve labor analgesia.

• Second, remifentanil is classified as drug category C (no well-controlled studies in pregnant women) by the Food and Drug Administration so its use is limited to situations where the benefits outweigh the potential risks, as its safety has not been established during childbirth.

This is really a frontline that many anesthesiologists do not cross, and reports like this increase the chance of more women receiving labor analgesia.

• Third, the characteristics and pharmacokinetic profile of dexmedetomidine (including slight sedation) make it an interesting adjuvant for labor pain relief.

• Fourth, the authors described a combination of drugs with synergistic effects that results in lower analgesic requirements and less maternal and neonatal adverse effects. The most important adverse effects of these drugs are maternal sedation, desaturation, arterial hypotension, nausea and vomiting. There is also a risk of foetal bradycardia and neonatal sedation and desaturation. The designed protocol included monitoring of vital data performed by a one to one assigned nurse, and it is one of the strengths of this study, the continuous monitoring of the patient, because these adverse effects could be potentially dangerous, especially the combination of sedation and vomits, that could develop in bronchopulmonary aspiration. Once described, new variations of the proposed doses of remifentanil and dexmedetomidine could be examined in order to alleviate the mother with less risk of adverse effects.

Because of its potential adverse effects, it is necessary to inform the patient, monitor her properly,[4] and train nurses and midwives in its administration. In The Netherlands, where epidural analgesia is not fully extended to the entire population, it has come to recommend PCA remifentanil from a cost-effectiveness seen as an analgesic technique of choice,[5] something that has been highly criticized.[6]

• Fifth, two groups of 30 healthy patients, were studied, a low number to allow us to accept definitively this PCA without further studies, but the statistical results, with lower pain scores (P < 0.001) in the remifentanil-dexmedetomidine group are promising. Other studies including more patients or different population, such as eclampsia or heart diseases are desirable. The same happens with the neonate outcome, only reported as APGAR scoring at 1 and 5 min. Other tests such as the neurobehavioral test should be included. In a series of 23 neonates there were no differences in hemodynamic or oxygen saturation during the first 24 h of life after receiving the mothers remifentanil PCA, although the authors describe a tendency to hypotension compared to infants whose mothers did not receive remifentanil during the 1 h.[7]

• Sixth, anesthesiologists usually felt more comfortable with common neuraxial techniques. The PCA remifentanil gets more labor analgesia than other opioids or intermittently inhaled nitrous oxide. However, the results are worse than neuraxial analgesia in nulliparous. The overall feeling is that remifentanil in PCA, although it is worth and gives good results with high rates of maternal satisfaction, fails to give an adequate level as neuraxial analgesia do and is often relegated to situations where the epidural is not feasible/workable.[1,8]

• And finally, the clearly described remifentanil-dexmedetomidine PCA offers an alternative to consider in some situations. This could be the start point of new investigations for supplementation of not fully functioning epidurals, a situation with a reported incidence of 3.5-32%.[8]