Remifentanil PCIA during labor and delivery: can we improve maternal monitoring?

Remifentanil patient controlled intravenous analgesia (PCIA) during labor has rapidly gained popularity. Its pharmacological profile makes it suitable for this indication. However, remifentanil is a potent respiratory depressant that might cause serious maternal hypoventilation, respiratory arrest and desaturation.

In the present study we compared standard monitoring of parturients (saturation measurements and visual respiratory rate measurements at set times) with continuous monitoring. Data of patients in the standard monitoring group were collected from handwritten charts containing oxygen saturation and respiratory rate. The patients in the continuous monitoring group were connected to a device that measures the oxygen saturation and respiratory rate every two seconds and automatically saves the data. These data were analyzed retrospectively.

In the standard monitoring group 1 patient (1%) had severe desaturation SpO₂ < 80%, 22 patients (25%) had SpO₂ < 94% and in no patient a respiratory rate (RR) < 8/min was recorded. In the continuous monitoring group 20 patients (33%) showed SpO₂ < 80%, 58 patients (97%) SpO₂ < 94% and 38 patients (63%) had bradypnea (RR < 8/min). The analysis of the data of the continuous monitoring group showed severe desaturations and serious respiratory depression.

The standard intermittent monitoring strategy dramatically underestimated the incidence of both bradypnea and oxygen desaturations with undetected hypoxemia and possible complications as a consequence. During use of remifentanil PCIA one-to-one midwifery care is advised. When obstetric caregivers are not present in the immediate vicinity of the parturient, high quality continuous monitoring, remote alarm notification and readiness for immediate corrective intervention are essential for safe use of this analgesic strategy.