Remifentanil at a Relatively Elevated Dose in Active Phase is Safe and More Suitable Than Fixed Lower Dose for Intravenous Labor Analgesia

Abstract

Background

Intravenous labor analgesia is recommended as an alternative for parturients who have contraindications to epidural analgesia. There are several opioid analgesics and different administering regimens used in the clinic. This study aimed to compare the effectiveness and safety of two intravenous remifentanil dosage regimens in the first labor stage.

Patients and Methods

One hundred and fifteen parturients with a contraindication to epidural analgesia but were willing to receive systemic labor analgesia were randomized into group A received a fixed dose of remifentanil throughout the first stage of labor, and group B received an elevated dose of remifentanil during the active phase of the first stage both by patient-controlled analgesia (PCA). Maternal numerical rating scale (NRS) pain score and oxygen desaturation, sedation efficacy, satisfaction, as well as maternal and fetal adverse reactions were recorded and compared.

Results

The mean NRS pain scores before analgesia and in the latent phase showed no statistically significant difference between the two groups (P > 0.05). However, during the active phase, group B demonstrated significantly lower mean NRS pain scores and lowest pain score compared to group A (P < 0.05). Furthermore, group B exhibited higher overall sedation scores and satisfaction scores in comparison to group A (P < 0.05). The incidence of adverse reactions between the two groups was similar (P > 0.05).

Conclusion

Relatively elevated intravenous dosage of remifentanil with PCA during the active phase in the first stage of labor is safe and more effective than a fixed-dosage regimen for labor analgesia.

Trial Registration

This study was registered with ChiCTR on 24/08/2021 with trial identification number: ChiCTR2100050247. First participant was recruited on 31/08/2021. The last patient was recruited on 12/08/2022.

Graphical Abstract

Keywords:

• patient-controlled analgesia
• PCA
• remifentanil
• labor analgesia
• intravenous administration
• opioids

Abbreviations

PCA, patient-controlled analgesia; NRS, numerical rating scale; ChiCTR, Chinese Clinical Trial Registry; HR, heart rate; BP, blood pressure; RR, respiratory rate; SpO₂, blood oxygen saturation; FHR, fetal heart rate; NRFHR, non-reassuring FHR; SD, standard deviation; BMI, body mass index.

Data Sharing Statement

The data presented in this study are available on request from the corresponding author (Jin Yu; [email protected]). The data are not publicly available because this was a clinical trial containing information that could compromise the privacy of research participants.

Ethics Approval and Consent to Participate

This trial was approved by the Medical Ethics Committee of Chongqing Health Center for Women and Children (reference number: 2021-028 on 03/08/2021) and registered with Chinese Clinical Trial Registry (ChiCTR) (www.chictr.org.cn, registration number: ChiCTR2100050247). The trial was performed in accordance with International Conference on Harmonization – Guidelines for Good Clinical Practice (ICH-GCP) and Declaration of Helsinki. Informed consents were obtained from all participants.

Acknowledgments

We are grateful to Prof. Yongchun Su at Chongqing Youyoubaobei Women and Children’s Hospital for his manuscript preparation assistance.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests in this work.

Additional information

Funding

This study was supported by Chongqing Maternal and Child Health Scientific Research and Cultivation Project (No. 2021FY106), Natural Science Foundation of Chongqing of China (No. cstc2021jcyj-msxmX0763) and National Key Clinical Speciality Construction Project (Obstetrics and Gynecology).