Effects of epidural neostigmine and clonidine in labor analgesia: A systematic review and meta-analysis

The Use of Muscle Relaxants in Pregnancy and Puerperium Period

Introduction

Anaesthetising a pregnant woman and during the postpartum period is challenging for most anaesthetists. There are many factors involved, including all the physiological changes that occur in the body of such a woman. Particular attention should be paid to muscle relaxants.

Aim

The purpose of this article is to present the use of muscle relaxants in pregnancy and puerperium period.

Material and Methods

This work is based on the available literature and the authors' experience.

Conclusion

In our experience and from a broad review of the medical literature, a great deal of caution should be exercised when using muscle relaxants during the anaesthesia of pregnant or postpartum patients. The pharmacodynamic and pharmacokinetic differences in the action of this group of drugs during this period should be known.

Antinociceptive Effects and Interaction Mechanisms of Intrathecal Pentazocine and Neostigmine in Two Different Pain Models in Rats

Background

Pentazocine produces a wide variety of actions in the treatment of perioperative analgesia. Neostigmine is a cholinesterase inhibitor used to antagonize the residual effects of muscle relaxants and also produces an analgesic effect.

Objectives

To investigate the analgesic effects of intrathecally injected pentazocine and neostigmine and their interaction.

Methods

Sprague–Dawley rats were used to test the analgesic effect of pentazocine and neostigmine using the paw formalin pain model and the incision mechanical allodynia model. Pentazocine (3, 10, 30, and 100 μg), neostigmine (0.3, 1, 3, and 10 μg) or a pentazocine-neostigmine mixture were separately injected to evaluate their antinociceptive effects alone on the treatment groups. The corresponding control group received an intrathecal injection containing the same volume of saline. The formalin pain test, or the plantar incision pain behavior test were performed 30 minutes later. Isobolographic analysis was used to evaluate the interaction between pentazocine and neostigmine. Intrathecally administered selective mu-opioid receptor antagonist CTAP, selective kappa-opioid receptor antagonist nor-Binaltorphimine (nor-BNI), nonselective opioid receptor antagonist naloxone, and muscarinic acetylcholine receptor antagonist atropine were also used to test the possible interaction mechanism. These antagonists were used 30 minutes before the pentazocine and neostigmine mixtures which were intrathecally injected.

Results

Intrathecally administered pentazocine (3, 10, 30, and 100 μg) and neostigmine (0.3, 1, 3, and 10 μg) alone had a marked dose-related impact on suppressing the biphasic responses in the formalin test. Pentazocine (3, 10, 30, and 100 μg) and neostigmine (0.3, 1, 3, and 10 μg) alone attenuated the mechanical allodynia in a plantar incision model in a dose-dependent manner. Isobolographic analysis revealed that the mixture of intrathecal pentazocine and neostigmine synergistically decreased both phase I and II activity in the formalin test and mechanical allodynia in the plantar incision model. Pretreatment of intrathecally administered nor-BNI, naloxone, atropine, but not CTAP, antagonized the analgesic effect of the pentazocine-neostigmine mixture.

Conclusions

All of these results suggest that the combined application of pentazocine and neostigmine is an effective way to relieve pain from formalin and acute incision mechanical allodynia. The synergistic effect between pentazocine and neostigmine is mostly attributed to the kappa-opioid receptor and the cholinergic receptor in the spinal cord.

Curative effect of remifentanil on labor analgesia in newborns

Objective: To investigate the curative effect of remifentanil on analgesia in newborns.Patients and methods: One hundred and twenty full-term puerperae from January 2013 to December 2013 were selected and randomly divided into three groups: remifentanil patient-controlled intravenous labor analgesia group (Group A, n = 40), patient-controlled epidural analgesia (PCEA) group (Group B, n = 40), and spontaneous labor group (Group C, n = 40). General conditions, visual analogue scale (VAS) score, labor stage, bleeding, delivery mode, neonatal asphyxia rate, oxyhemoglobin saturation in puerpera, and umbilical arterial blood gas analysis indexes of the fetus were measured. In addition, complications and adverse reactions were recorded.Results: VAS scores in Group A and B were significantly lower than that in Group C at each time point after analgesic intervention (p < .05), without differences at 30 min and 1 h after analgesia between Group A and B (p > .05). However, VAS scores in Group A were significantly higher than those in Group B at the full opening of the uterine orifice and fetal delivery (p < .05). The active phases in the first stage of labor in Group A and B were significantly shorter than that in Group C (p <.05). There were no significant differences in general conditions, VAS score before analgesia, the second and third stages of labor, delivery mode, bleeding, neonatal asphyxia rate, oxyhemoglobin saturation, pH value, partial pressure of oxygen (PO₂), and partial pressure of carbon dioxide (PCO₂) among three groups (p > .05).Conclusions: Remifentanil intravenous labor analgesia is not superior to PCEA, but does not increase adverse effects, suggesting it might be a supplementary method of PCEA.

Implementation of Robert's Coping with Labor Algorithm© in a large tertiary care facility

OBJECTIVE

to implement use of Roberts' Coping with Labor Algorithm^© (CWLA) with laboring women in a large tertiary care facility.

DESIGN

this was a quality improvement project to implement an alternate approach to pain assessment during labor. It included system assessment for change readiness, implementation of the algorithm across a 6-week period, evaluation of usefulness by nursing staff, and determination of sustained change at one month. Stakeholder Theory (Friedman and Miles, 2002) and Deming's (1982) Plan-Do-Check-Act Cycle, as adapted by Roberts et al (2010), provided the framework for project implementation.

SETTING

the project was undertaken on a labor and delivery (L&D) unit of a large tertiary care facility in a southwestern state in the USA. The unit had 19 suites with close to 6000 laboring patients each year.

PARTICIPANTS

full, part-time, and per diem Registered Nurse (RN) staff (N=80), including a subset (n=18) who served as the pilot group and champions for implementing the change.

FINDINGS

a majority of RNs held a positive attitude toward use of the CWLA to assess laboring women's coping with the pain of labor as compared to a Numeric Rating Scale (NRS). RNs reported usefulness in using the CWLA with patients from a wide variety of ethnicities. A pre-existing well-developed team which advocated for evidence-based practice on the unit proved to be a significant strength which promoted rapid change in practice.

IMPLICATIONS FOR PRACTICE

this work provides important knowledge supporting use of the CWLA in a large tertiary care facility and an approach for effectively implementing that change. Strengths identified in this project contributed to rapid implementation and could be emulated in other facilities. Participant reports support usefulness of the CWLA with patients of varied ethnicity. Assessment of change sustainability at 1 and 6 months demonstrated widespread use of the algorithm though long-term determination is yet needed.