Nitrous Oxide Utility in Labor and Birth: A Multipurpose Modality

Analgesic effect of nitrous oxide during manual therapy after anterior cruciate ligament reconstruction: a study protocol for a randomized controlled trial

BACKGROUND

Many patients during manual therapy after anterior ligament reconstruction will experience severe pain, which has a negative impact on their rehabilitation. However, there is rarely an analgesic method for these patients during rehabilitation. Nitrous oxide with rapid analgesic and sedative effects is often used to relieve pain in minor procedures. The purpose of this study is to determine whether or not nitrous oxide analgesia decreases pain compared to oxygen during manual therapy after anterior ligament reconstruction.

METHODS/DESIGN

This single-center, randomized, double-blind and controlled trial will recruit 120 patients. Patients ≥ 18 years old undergoing manual therapy after anterior ligament reconstruction (1 month post-operative) with acute pain (VAS ≥ 4) are included. The main exclusion criteria included the following: pulmonary embolism, intestinal obstruction, pneumothorax. Patients will be randomly allocated to the intervention group (A) and the control group (B) in a ratio of 1:1. Doctors, therapists, patients, and data collectors are all blind to the study. The manual therapy will be performed by therapists. Nurses who implemented the intervention handed the doctors envelopes containing the patients' codes and allocation of A or B. Group A will receive a pre-prepared nitrous oxide/oxygen mixture plus conventional treatment (no analgesic) given as 30-min treatment sessions, once daily, and group B will receive oxygen plus conventional treatment (no analgesic) under the same conditions. Assessments will be taken 2 min before the intervention (T0), 5 min after the beginning of the intervention (T1), and 5 min after the intervention finished (T2). The primary outcome is pain score. Secondary outcomes include vital signs, side effects, joint range of motion, adjuvant analgesia need, therapist and patient satisfaction, and whether willing to receive the same gas again.

EXPECTED OUTCOMES

We expect nitrous oxide inhalation to have a beneficial effect on the pain of patients who receive manual therapy after anterior ligament reconstruction.

DISCUSSION

If this treatment appears beneficial, it could improve patients' satisfaction and quality of life potentially and even be implemented widely in hospital and rehabilitation settings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, ChiCTR2200061175 (Version 2.0 June 15, 2022), https://www.chictr.org.cn .

Women's perspectives of nitrous oxide for labour and procedural analgesia: A prospective clinical audit and cross-sectional study. "It's the best thing"

PROBLEM

There is limited data regarding dose and duration of nitrous oxide use by women in peripartum care. Experiences of using nitrous in Australian settings have not previously been explored BACKGROUND: More than 1:2 women use nitrous oxide analgesia during labour and birth, despite this, there are limited published data on nitrous oxide use for labour or procedural analgesia in Australia.

AIM

To explore the use of nitrous oxide during labour and birth or procedural care.

METHODS

A two-phased sequential design was used; clinical audit (n = 183) and cross-sectional survey (n = 137) approaches supported data collection. Quantitative data were analysed using descriptive and inferential statistics, qualitative data underwent content analysis.

FINDINGS

Nitrous oxide was used by primiparous and multiparous women evenly. Duration of labour-use ranged from < 15 min (10.9%) to > 5 h (10.8%), with equal representation between > 50% concentration (43%) and < 50% (43%). At audit, 75% found nitrous useful; postpartum maternal satisfaction scores remained high, mean indicators were 75%. More multiparous women found nitrous oxide useful than primiparous (95%vs80%,p = 0.009). There was no association between perceived usefulness and whether women were in spontaneous, augmented or induced labour; regardless of concentrations reached. Three key themes described women's perspectives of physical and psycho-emotional effects and challenges.

DISCUSSION

Nitrous oxide plays an important role in the provision of analgesia during procedural or labour and birth care. Service provision, parent and professional education, and future service design will benefit from these novel findings confirming the utility and acceptability of nitrous oxide use in contemporary maternity care.

Nitrous Oxide Use in Australian Health Care: Strategies to Reduce the Climate Impact

Nitrous oxide is a useful inhaled analgesic. Due to its high global warming potential and ozone-depleting properties, the nitrous oxide emissions related to health care are being increasingly scrutinized. In this narrative review, we will discuss the clinical uses of nitrous oxide relevant to anesthetists, in addition to its contribution as a greenhouse gas. Using available data from Australia, we will explore potential strategies for reducing the impact of those emissions, which are likely to be applicable in other countries. These include destruction of captured nitrous oxide, minimizing nitrous oxide waste and reducing clinical use. Anesthesia clinicians are well placed to raise awareness with colleagues and consumers regarding the environmental impact of nitrous oxide and to promote cleaner alternatives. Reducing use is likely to be the most promising reduction strategy without large-scale changes to infrastructure and subsequent delay in action.

Effect of nitrous oxide use on external cephalic version success rate; a systematic review and meta-analysis

INTRODUCTION

Several adjuvant interventions have been evaluated for improving the success rate of the external cephalic version (ECV) and reducing the rate of cesarean delivery (CD). Evidence regarding the effect of Nitrous oxide is limited to a small number of participants with inconsistent results on pain score and success rate. This study aims to examine the effect of inhaled nitrous oxide on the success rate and pain score for women undergoing ECV.

MATERIAL AND METHODS

Survey on ECV reports from inception till June 2020 were made from MEDLINE, EMBASE, PubMed, Ovid Medline, ClinicalTrials.gov, the Cochrane Library and Google Scholars. Peer-review studies that examined the success rate of ECV from the application of nitrous oxide during ECV attempts compared with or without the use of other analgesic agents were obtained. The study population comprising women with singleton pregnancies having a non-vertex presentation at least 36 weeks, were categorized into one of two treatment groups: ECV attempt with nitrous oxide (nitrous oxide group) and ECV attempt with or without another analgesia (control group). The primary outcome was the ECV success rate, defined by conversion to vertex-presentation following the procedure. The secondary outcomes were pain scores during ECV attempt and CD rate. The study quality scores were evaluated as a source of heterogeneity by fitting meta-regression models to the individual study effect sizes.

RESULTS

Of the 26 records identified, two randomized trials and one prospective cohort study (720 women; 434 in the nitrous oxide group and 286 controls) were deemed adequate for meta-analysis. ECV success rate did not differ significantly between the nitrous oxide group and the control group (p = .825; OR 1.036; 95% CI, 0.756, 1.419). In addition, the use of nitrous oxide did not affect pain scores during ECV attempt (p = .457; OR 0.759; 95% CI, -1.240, 2.759) and there was no difference in the incidence of CD as well (p = .943; OR 1.013; 95% CI, 0.703, 1.46).

CONCLUSION

The use of nitrous oxide during ECV attempts was not associated with an increase in ECV success rate and does not affect pain scores. PROSPERO Registration No. CRD42020197933.

Association of Self-Administered Nitrous Oxide for Labor Analgesia With Maternal and Neonatal Process and Outcome Measures

OBJECTIVE

To describe patterns of use of self-administered nitrous oxide (N₂O) during labor and to determine if maternal and neonatal process and outcome measures differ for women who use N₂O compared to women who do not use N₂O.

DESIGN

Retrospective, full-census, observational cohort.

SETTING

An upper midwestern U.S., urban, 75-bed quaternary perinatal center with more than 5,000 annual births.

PARTICIPANTS

The participants included two groups of women: 400 who used N₂O during labor and a comparison group of 6,733 who met N₂O eligibility but did not use N₂O.

METHODS

We used descriptive statistics to examine patterns of use of N₂O during labor between January 2015 and March 2017. We examined associations of N₂O with process (length of first and second stages of labor, time from hospital admission to birth, time from birth to hospital discharge, and total length of stay) and outcome measures (shoulder dystocia, instrumentation, vaginal lacerations, Apgar scores at 5 minutes, nursery disposition) using multivariate linear, logistic, and ordinal regression models.

RESULTS

Three percent (12/400) of women who used N₂O discontinued because of side effects. Among participants with vaginal births who used N₂O, 17.6% (62/352) used N₂O as the only form of pain medication during labor. We found no significant differences in maternal and neonatal outcome measures between the two groups. Among the process measures examined, we found a mean 2-hour-longer time from admission to birth and total length of stay in the N₂O group (p < .05) compared to the non-N₂O group.

CONCLUSION

Most participants who used N₂O (290/352, 82.3%) transitioned to other pain modalities during labor. Maternal and neonatal process and outcome measures were comparable relative to other pain management modalities, with the exception of longer time durations for two measures.

Reviewing pain management options for patients in active labor

Pain perception and preferences for pain management are unique to each woman in labor. This article provides an overview of the physiology of labor pain, discusses available nonpharmacologic and pharmacologic approaches to managing pain during active labor, and discusses potential benefits and risks for each option.

Effectiveness of nitrous oxide in external cephalic version on success rate: A randomized controlled trial

INTRODUCTION

Approximately 4% of singleton pregnancies at term are in breech presentation. External cephalic version (ECV) can reduce the risks of noncephalic birth and cesarean delivery, but this maneuver can be painful. Our aim was to analyze the effect of administering inhaled nitrous oxide for analgesia on the ECV success rate.

MATERIAL AND METHODS

This prospective, randomized, single-blind, controlled trial included women with singleton pregnancies in breech presentation at term who were referred for ECV in a tertiary care center. Women were assigned according to a balanced (1:1) restricted randomization design to inhale either nitrous oxide (N₂ O) in a 50:50 mix with oxygen or medical air during the procedure. The main outcomes reported are the ECV success rate, degree of pain, adverse event rate, and women's satisfaction.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01948115.

RESULTS

The study included 150 women (nitrous oxide group: n = 74; medical air: n = 76). Inhaled nitrous oxide was not associated with a higher ECV success rate than medical air (24.3 vs 19.7%, P = 0.51). Among parous women (n = 34 in each group), the ECV success rate appeared higher in the nitrous oxide group, respectively 47.1% (n = 16) vs 23.5% (n = 8) (P = 0.042). Neither the median pain level nor adverse event rates differed significantly in women with inhaled nitrous oxide compared with medical air.

CONCLUSIONS

Use of an equimolar mixture of oxygen and nitrous oxide during ECV appears safe. Although it does not seem to change the overall success rate, it may increase success in parous women.