Safety and Risks of Nitrous Oxide Labor Analgesia: A Review

Association Between Intrapartum Nitrous Oxide for Labor Analgesia and Short-Term Neonatal Outcomes

OBJECTIVE

To evaluate the association between intrapartum nitrous oxide use and adverse short-term neonatal outcomes.

METHODS

This was a retrospective cohort study of individuals with singleton gestations at 35 or more weeks who attempted labor and delivered at an academic hospital between June 1, 2015, and February 28, 2020. Data were extracted from the electronic medical record using billing and diagnostic codes. Patients were classified based on whether they received no intrapartum analgesia or received nitrous oxide only. Those who received other analgesia types were excluded. The primary outcome was neonatal intensive care unit (NICU) admission. Secondary outcomes included Apgar score less than 7 at 1 minute and 5 minutes, respiratory composite outcome (including meconium aspiration syndrome, neonatal bronchopulmonary disorders, neonatal transient tachypnea, and other neonatal respiratory distress that required NICU admission), hypoglycemia, and hyperbilirubinemia. Univariable and multivariable analyses were used to estimate the association between nitrous oxide exposure intrapartum and the selected outcomes.

RESULTS

Of 6,047 included, 4,153 (68.7%) received no analgesia, and 1,894 (31.3%) received nitrous oxide only. In comparison with individuals who received no analgesia, those who received nitrous oxide were more likely to be nulliparous, be of Black racial identity, have noncommercial insurance, and be less likely to deliver by intrapartum cesarean. The reception of nitrous oxide, compared with the reception of no analgesia, was associated with a lower likelihood of NICU admission (6.4% vs 8.1%; adjusted odds ratio [aOR] 0.77, 95% CI, 0.62-0.96) and an increased likelihood of neonatal hyperbilirubinemia (aOR 1.23, 95% CI, 1.08-1.41). Inhaled nitrous oxide exposure, in comparison with the reception of no analgesia, was not associated with the other secondary outcomes, including Apgar score less than 7 at 1 minute (odds ratio [OR] 0.74, 95% CI, 0.50-1.10) or 5 minutes (OR 0.91, 95% CI, 0.32-2.60), respiratory composite outcome (OR 0.91, 95% CI, 0.70-1.17), and hypoglycemia (OR 0.82, 95% CI, 0.64-1.05).

CONCLUSION

In this single-center retrospective cohort of low-risk patients, intrapartum inhaled nitrous oxide, compared with the reception of no analgesia, was associated with a decreased risk for NICU admission but with an increased risk for hyperbilirubinemia; other outcomes did not differ. These findings may be used to counsel patients when considering nitrous oxide for labor analgesia.

A Pharmacotherapeutic Approaches for Managing Labour Pain Using Synthetic Drugs and Natural Therapies

The birth of a child is a critical and potentially traumatic experience for women, entailing multiple physiological and psychosocial changes. The psychological effects of childbirth pain can have both immediate and long-term effects on the mother's health and her bond with her child. Many studies investigated the different ranges of synthetic drugs available for pain control in labour, inclusive of neuraxial analgesics, inhaled analgesics, and various opioids. The inadequate efficacy and unfavourable side effects of these synthetic drugs prevent appropriate pharmacotherapy, resulting in a quest for natural therapies for reducing labour pain. Herbal therapies (aromatherapy) using several essential oils obtained from various natural plants are another alternative that calms and manages the mind and body through aromatic compounds that have neurological and physiological effects. The review discussed the safety profile of various synthetic drugs with their dosage information and also deliberated on the mechanism and safety profile of various natural plants that are used in aromatherapy. The review also briefly highlighted the other non-pharmacological miscellaneous techniques such as TENS, hypnosis, immersion in water, acupuncture, massage, and different other tactics that aim to assist women in coping with pain in labour.

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.

A survey of Australian midwives: Experts in nitrous oxide administration within the peripartum setting

PROBLEM

There is little documented evidence of midwives' perspectives regarding the use of nitrous oxide in the peripartum period.

BACKGROUND

Nitrous oxide is an inhaled gas used widely in the peripartum period; usually offered and managed by midwives.

AIM

Explore midwives' knowledge, perceptions, and practices of facilitating women's use of nitrous oxide in the peripartum period.

METHODS

An exploratory cross-sectional survey design was used. Quantitative data were analysed using descriptive and inferential statistics; open-ended responses underwent template analysis.

FINDINGS

Midwives (n = 121) working in three Australian settings reported regularly recommending the use of nitrous oxide and high levels of knowledge and confidence supporting its use. There was a significant association between midwifery experience, and perspectives on women's capacity to use nitrous effectively (p = 0.004); and desire for refresher education (p < 0.001). Midwives working in continuity models were more likely to support women using nitrous oxide in any situation (p = 0.039).

DISCUSSION

Midwives demonstrated expertise in facilitating nitrous oxide use, citing utility to relieve anxiety and distract women from pain or discomfort. Nitrous oxide was identified as an important adjunct to the provision of supportive care requiring midwifery therapeutic presence.

CONCLUSION

This study provides novel insight into midwives' support of nitrous oxide use in the peripartum setting revealing high levels of knowledge and confidence. Recognition of this unique expertise held by midwives is important to ensure transfer and development of professional knowledge and skills and emphasises the need for midwifery leadership in clinical service provision, planning and policy.

Protective effect of platinum nano-antioxidant and nitric oxide against hepatic ischemia-reperfusion injury

Therapeutic interventions of hepatic ischemia-reperfusion injury to attenuate liver dysfunction or multiple organ failure following liver surgery and transplantation remain limited. Here we present an innovative strategy by integrating a platinum nanoantioxidant and inducible nitric oxide synthase into the zeolitic imidazolate framework-8 based hybrid nanoreactor for effective prevention of ischemia-reperfusion injury. We show that platinum nanoantioxidant can scavenge excessive reactive oxygen species at the injury site and meanwhile generate oxygen for subsequent synthesis of nitric oxide under the catalysis of nitric oxide synthase. We find that such cascade reaction successfully achieves dual protection for the liver through reactive oxygen species clearance and nitric oxide regulation, enabling reduction of oxidative stress, inhibition of macrophage activation and neutrophil recruitment, and ensuring suppression of proinflammatory cytokines. The current work establishes a proof of concept of multifunctional nanotherapeutics against ischemia-reperfusion injury, which may provide a promising intervention solution in clinical use.

Beyond the epidural: Alternatives to neuraxial labor analgesia

Labor creates an intense pain experienced by women across the world. Although neuraxial analgesia is the most effective treatment of labor pain, in many cases, it may not be undesired, not available, or have contraindications. In addition, satisfaction with labor analgesia is not only determined by the efficacy of analgesia but a woman's sense of agency and involvement in the childbirth experience are also key contributors. Providing safe choices for labor analgesia and support is central to creating a tailored, safe, and effective analgesic treatment plan with high maternal satisfaction. Healthcare provider knowledge of various nonneuraxial analgesic options, including efficacy, contraindications, safe clinical implementation, and side effects of various techniques is needed for optimal patient care and satisfaction. Future rigorous scientific studies addressing all of these labor analgesia options are needed to improve our understanding. This review summarizes the current published literature for commonly available non-neuraxial labor analgesic options.

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.

Nitrous Oxide for Labor Analgesia: What We Know to Date

Background: Although nitrous oxide (N₂O) has been used since the 1880s for labor analgesia, its popularity has only recently increased in the United States. In 2011, only 3 centers in the country offered N₂O, but as of 2020, several hundred labor units have adopted its use.

Methods: We reviewed the literature and summarize the mechanism of action, clinical uses, and efficacy of N₂O for labor analgesia, as well as patient satisfaction related to its use.

Results: N₂O has several proposed mechanisms of action that make it a viable option for all 3 stages of labor and postpartum procedures. N₂O has been shown to be a safe option for both mom and baby during labor and delivery. Studies support N₂O as an analgesic for laboring. Even though 40% to 60% of women who use N₂O convert to a labor epidural analgesia, satisfaction surveys indicate that analgesia is not the only factor contributing to the use of N₂O during labor.

Conclusion: The use of N₂O has increased in labor and delivery units across the United States since 2011. Despite inferior analgesic properties compared to epidural analgesia, N₂O offers a safe alternative for many parturients who want a greater sense of control and mobility.

Pain management during labor and vaginal birth

Neuraxial analgesia provides excellent pain relief in labor. Optimizing initiation and maintenance of neuraxial labor analgesia requires different strategies. Combined spinal-epidurals or dural puncture epidurals may offer advantages over traditional epidurals. Ultrasound is useful in certain patients. Maintenance of analgesia is best achieved with a background regimen (either programmed intermittent boluses or a continuous epidural infusion) supplemented with patient-controlled epidural analgesia and using dilute local anesthetics combined with opioids such as fentanyl. Nitrous oxide and systemic opioids are also used for pain relief. Nitrous oxide may improve satisfaction despite variable effects on pain. Systemic opioids can be administered by healthcare providers or using patient-controlled analgesia. Appropriate choice of drug should take into account the stage and progression of labor, local safety protocols, and maternal and fetal/neonatal side effects. Pain in labor is complex, and women should fully participate in the decision-making process before any one modality is selected.

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.

European Society of Anaesthesiology Task Force on Nitrous Oxide: a narrative review of its role in clinical practice

Nitrous oxide (N₂O) is one of the oldest drugs still in use in medicine. Despite its superior pharmacokinetic properties, controversy remains over its continued use in clinical practice, reflecting in part significant improvements in the pharmacology of other anaesthetic agents and developing awareness of its shortcomings. This narrative review describes current knowledge regarding the clinical use of N₂O based on a systematic and critical analysis of the available scientific literature. The pharmacological properties of N₂O are reviewed in detail along with current evidence for the indications and contraindications of this drug in specific settings, both in perioperative care and in procedural sedation. Novel potential applications for N₂O for the prevention or treatment of chronic pain and depression are also discussed. In view of the available evidence, we recommend that the supply of N₂O in hospitals be maintained while encouraging its economic delivery using modern low flow delivery systems. Future research into its potential novel applications in prevention or treatment of chronic conditions should be pursued to better identify its role place in the developing era of precision medicine.

A Review of the Impact of Obstetric Anesthesia on Maternal and Neonatal Outcomes

Obstetric anesthesia has evolved over the course of its history to encompass comprehensive aspects of maternal care, ranging from cesarean delivery anesthesia and labor analgesia to maternal resuscitation and patient safety. Anesthesiologists are concerned with maternal and neonatal outcomes, and with preventing and managing complications that may present during childbirth. The current review will focus on recent advances in obstetric anesthesia, including labor anesthesia and analgesia, cesarean delivery anesthesia and analgesia, the effects of maternal anesthesia on breastfeeding and fever, and maternal safety. The impact of these advances on maternal and neonatal outcomes is discussed. Past and future progress in this field will continue to have significant implications on the health of women and children.

Implementation of an Evidence-Based Practice Change to Offer Nitrous Oxide During Labor

OBJECTIVE

The aim of this evidence-based practice change was to implement use of nitrous oxide as a pain management option during labor and to examine women's satisfaction with that option.

DESIGN

Evidence-based practice change guided by the model for evidence-based practice change.

SETTING

Labor and delivery unit in a tertiary medical center in the southwestern United States.

PARTICIPANTS

Laboring women who met eligibility criteria were offered the option of nitrous oxide during a 2-month period.

MEASUREMENTS

Process indicators to measure compliance with the practice change among staff, uptake of nitrous oxide among women, and women's satisfaction with the choice to use nitrous oxide.

RESULTS

Nitrous oxide was offered to 26% (n = 55) of eligible women. Most of the 55 women who used nitrous oxide during the implementation period reported satisfaction with it and indicated that they would consider nitrous oxide for a future labor.

CONCLUSION

Our experience implementing a practice change to offer nitrous oxide to laboring women indicated that use of nitrous oxide was feasible in this setting and that women were receptive to this option, were satisfied with its use, and would use nitrous oxide for a future labor.

Managing pain and anxiety during transabdominal chorionic villus sampling. A noninferiority randomized trial of nitrous oxide vs local anesthesia

INTRODUCTION

Transabdominal chorionic villus sampling (CVS) is an invasive procedure for prenatal diagnosis reported to be associated with anxiety and pain. In this context, the need for analgesia during CVS has been considered useful. Even though several authors have been interested in pain management during amniocentesis, no study has been published on pain reduction during CVS. Our objective was to evaluate pain and anxiety management during transabdominal CVS using nitrous oxide (N₂ O) and local anesthesia.

MATERIAL AND METHODS

In a randomized controlled noninferiority trial, self-administered nitrous oxide (N₂ O) inhalation (equimolar premix of oxygen and nitrous oxide) was compared with local anesthesia (1% lidocaine) before CVS. Primary outcome was pain and secondary outcome was anxiety, both measured on a visual analog scale 30-60 minutes before, immediately after (5-10 minutes) and 30-60 minutes after CVS. With a statistical power of 90%, type I error of 5% and two-sided test and potential exclusions, a sample size of 96 patients per group was enrolled and randomized. No patient was enrolled before the trial registration date.

RESULTS

From 13 March 2013 through 10 February 2015, 192 patients (96 per group) were screened and randomized. Most characteristics were similar across groups. Pain in the N₂ O group was 2.65 ± 0.22 vs 3.32 ± 0.26 in local anesthesia group [mean ± standard error of mean  (SEM)]. Mean anxiety in the N₂ O group was 3.17 ± 0.27 vs 5.19 ± 0.30 in the local anesthesia group.

CONCLUSION

N₂ O was as efficient and even superior to local anesthesia for both pain and anxiety reduction during CVS, as the 95% confidence intervals were both below the prespecified noninferiority margin of 0.8 and below zero.

Nitrous oxide for labor analgesia

Inhaled nitrous oxide (N2O) has been used worldwide for over 100 years as labor analgesia but has not gained widespread use in the United States. Nitrous oxide provides a noninvasive option for laboring women. This article outlines its efficacy and safety as an analgesic compared with epidural and IV pain medications.

ABM Clinical Protocol #28, Peripartum Analgesia and Anesthesia for the Breastfeeding Mother

A central goal of the Academy of Breastfeeding Medicine is the development of clinical protocols, free from commercial interest or influence, for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Non-Neuraxial Labor Analgesia: Options

Although it is the most effective method to treat labor pain, neuraxial analgesia may be undesired, contraindicated, unsuccessful, or unavailable. Providing safe choices for labor pain relief is a central goal of health care providers alike. Consequently, knowledge of the efficacy, clinical implementation, and side effects of various non-neuraxial strategies is needed to provide appropriate options for laboring patients. In addition to nonpharmacologic alternatives, inhaled nitrous oxide and systemic opioids represent two broad classes of non-neuraxial pharmacologic labor analgesia most commonly available. This review summarizes the current published literature for these non-neuraxial labor analgesic options.

Health Effects Associated With Exposure to Anesthetic Gas Nitrous Oxide-N2O in Clinical Hospital - Shtip Personel

AIM:

To show certain health effects associated with acute and chronic exposure to nitrous oxide of staff of the Department of Anaesthesiology and Intensive Care at the Clinical Hospital in Shtip.

METHODS:

A transversal study was conducted, that include 43 health workers (23 – exposed and 20 - unexposed). Personal exposure to nitrous oxide for this group members was assessed through continuous measurement over 8 hours shift within breathing zone of the subjects involved, using handheld electrochemical instrument with datalogging option direct. In order to determine presence of possible health effects associated with acute and chronic exposure to nitrous oxide in ORs and ICUs, a specially designed questionnaire was prepared and distributed to be anonymously filled out, by all the examinees from both examined groups. Data were statistically tested for normality and also quantitative and qualitative assessment was performed.

RESULTS:

From the results obtained, a significant difference in several health effects between exposed and unexposed groups can be noted, including headaches, dizziness, nausea and vomiting, euphoria and tachycardia. Regarding the excitement, the appearance of depression, the feeling of numbness and tingling of the hands and feet, the differences between the two examined groups were not significant.

CONCLUSION:

It can be concluded that chronic exposure to nitrous oxide is associated with the adverse health effects.

Nitrous oxide labor analgesia and pain relief memory in breastfeeding women

OBJECTIVE

The use of labor pain relief medications is a controversial issue that has engendered heated discussions among health care professionals about safety, interference with birthing, and breastfeeding.

METHODS

This is a case-control study with 62 puerperae treated with nitrous oxide and 124 control women (ratio 1:2), matched for age, gestational age, parity, delivery route, labor augmentation, and spinal regional analgesia. We tested anhedonia, anxiety, and depression symptoms at hospital discharge by The Edinburgh Postnatal Depression Scale (EPDS), and the intensity of nitrous oxide labor pain relief and satisfaction memory by a retrospective Visual Analog Scale (VAS, 0-10 Numeric Rating Scale) at a set cut off time of 3 months of a child's age.

RESULTS

Nitrous oxide use did not influence EPDS subscales upon discharge. Its use was instead associated with a lasting positive labor pain relief experience (VAS, 7.3 ± 2.2) in 83.5% of women, and labor satisfaction memory (VAS, 8.9 ± 1.8) in 90% of women, respectively, and with a significantly higher breastfeeding rates from the seventh day after discharge (p < .031), to the 1st (p < .043), and the third month of life (p < .016).

CONCLUSIONS

Nitrous oxide labor analgesia is associated with favorable effects on both women's psychoemotional experience of labor and breastfeeding success.

Drug therapy during pregnancy: implications for dental practice

Pregnancy is accompanied by various physiological and physical changes, including those found in the cardiovascular, respiratory, gastrointestinal, renal and haematological systems. These alterations in the pregnant patient may potentially affect drug pharmacokinetics. Also, pharmacotherapy presents a unique matter due to the potential teratogenic effects of certain drugs. Although medications prescribed by dentists are generally safe during pregnancy, some modifications may be needed. In this article we will discuss the changes in the physiology during pregnancy and its impact on drug therapy. Specific emphasis will be given to the drugs commonly given by dentists, namely, local anaesthetics, analgesics, antibiotics and sedatives.

A Nurse-Directed Model for Nitrous Oxide Use During Labor

BACKGROUND

Nitrous oxide has a long history of use and has been well documented in the literature as a safe, effective, and inexpensive option for pain management in labor in other countries, but it is underused in the United States.

LOCAL PROBLEM

Pain relief options for laboring women in rural community hospitals with a small perinatal service are limited due to lack of availability of in-house anesthesia coverage.

METHOD

This quality improvement project involved development and implementation of a nurse-driven, self-administered, demand-flow nitrous oxide program as an option for pain relief for laboring women in a rural community hospital.

INTERVENTION

Women's Services registered nurses developed the project using an interdisciplinary team approach based on an extensive literature review and consultation with experts across the country. The hospital is part of a large healthcare system; approval was sought and obtained by the system as part of the project. Cost analysis and patient satisfaction data were evaluated. Outcomes were monitored.

RESULTS

Approximately one half of the patients who have given birth at the hospital since initiation of the project have used nitrous oxide during labor. The majority of women who participated in a survey after birth found it helpful during mild-to-moderate labor pain. No adverse effects have noted in either the mother or the baby following nitrous oxide use.

CLINICAL IMPLICATIONS

Initiation and management of nitrous oxide by registered nurses is a safe and cost-effective option for labor pain. It may be especially beneficial in hospitals that do not have 24/7 in-house anesthesia coverage.

Should Nitrous Oxide Be Used for Laboring Patients?

Nitrous oxide, long used during labor in Europe, is gaining popularity in the United States. It offers many beneficial attributes, with few drawbacks. Cost, safety, and side effect profiles are favorable. Analgesic effectiveness is highly variable, yet maternal satisfaction is often high among the women who choose to use it. Despite being less effective in treating labor pain than neuraxial analgesic modalities, nitrous oxide serves the needs and preferences of a subset of laboring parturients. Nitrous oxide should, therefore, be considered for inclusion in the repertoire of modalities used to alleviate pain and facilitate effective coping during labor.

Effect of Entonox on reducing the need for Pethidine and the Relevant Fetal and Maternal Complications for Painless Labor

Background

Pain relief during labour is one of the major concerns in obstetrics; severe labor pain causes fear of the next pregnancy, and interferes with the mother’s family relationship.

Objective

The aim of this study was to evaluate the analgesic effects of Entonox during labor on reducing the need for pethidine (Meperidine) and fetal-maternal complications.

Methods

This double-blind randomized clinical trial was conducted on pregnant women who were candidates for vaginal delivery in Educational Hospitals of Mashhad University of Medical Sciences, Iran between January 2014 and November 2015. After entering into the inactive phase of labor, participants were randomly allocated to receive inhaled Entonox gas (n=200) or inhale Oxygen (n=200) as a control group. Mothers inhaled the gas at commencement of pain, and ceased as soon as the pain diminished, up to the end of the second stage of labor which was the neonate’s birth. Main outcomes were pain score based on NRS (numerical rating scale), duration of delivery, required pethidine, maternal complications and satisfaction during labour. Chi-square and Independent T-test were used via SPSS for data analysis and P-value less than 0.05 was considered statistically significant.

Results

Four-hundred pregnant women with a mean age of 26.4±5.9 years were studied. Complications such as nausea, vomiting, dizziness, and drowsiness were reported in 25% of the Entonox group and 23% in the control group (p=0.640). Mean of pain severity score during labor in the Entonox and control groups was 4.5±1.2 and 5.2±1.4, respectively (p<0.001). Pethidine requirement, significantly was lower in the Entonox group (31.6±11.8 versus 35.7±12.4; p<0.001).

Conclusion

In our study, Entonox significantly reduced pain during delivery without significant increase in maternal and neonatal complications.

Trial registration

The trial is registered at the Iranian Clinical Trial Registry (IRCT.ir) with the IRCT identification number IRCT2015102713159N6.

Funding

This research has been financially supported by Research Council of Mashhad University of Medical Sciences.

A Randomized Controlled Trial Comparing Use of Enthonox With Pethidine for Pain Relief in Primigravid Women During the Active Phase of Labor

Background

The use of pain-relieving drugs during labor is now part of standard care in many countries throughout the world. Each method of pain relief has its own risks and benefits, variations in effectiveness, and availability and acceptability.

Objectives

This study aimed to assess the efficacy and safety of intramuscular pethidine as an analgesic during labor by comparing it to inhaled 50% nitrous oxide (Entonox).

Methods

In this clinical trial study, 100 women who expected to have a natural childbirth were observed. The inclusion criteria for this study were the commencement of spontaneous labor pain along with appropriate maternal and fetal indications for vaginal delivery. By using random numbers, each subject was randomly allocated to one of two groups, with one group using Entonox and the other receiving an intramuscular injection of 0.5 mg/kg of pethidine for pain relief. The intensity of labor pain experienced by the subjects and the outcomes of the deliveries were collected with questionnaires.

Results

The average pain scores in the Entonox and pethidine groups were 3.94 ± 1.4 and 5.6 ± 1.1, respectively, 30 minutes after intervention (P = 0.001), but there was not a significant difference in the severity of the pain (5.06 ± 1.4 and 4.7 ± 1.1 for the Entonox and pethidine groups, respectively) between the subjects in each group 60 minutes after the intervention (P = 0.592). No significant differences were seen in the duration and interval of uterine contractions, maternal complications, Apgar scores, and the duration of the first and second stage of labor between the two studied groups (P > 0.05). An analysis of the pooled risk differences showed that none of the side effects investigated were significantly different between the two groups except for mouth dryness, which was significantly higher in nitrous oxide users (P = 0.044).

Conclusions

Inhaled nitrous oxide seems to give better pain relief in the short term compared to a single dose of pethidine. Entonox, which is more convenient to administer than an intramuscular injection of pethidine, is also regarded as safe both for mothers and neonates.

Risk Assessment of Using Entonox for the Relief of Labor Pain: A Healthcare Failure Modes and Effects Analysis Approach

INTRODUCTION

In order to prevent medical errors, it is important to know why they occur and to identify their causes. Healthcare failure modes and effects analysis (HFMEA) is a type of qualitative descriptive that is used to evaluate the risk. The aim of this study was to assess the risks of using Entonox for labor pain by HFMEA.

METHODS

A mixed-methods design (qualitative action research and quantitative cross-sectional research) was used. The modes and effects of failures in the process of using Entonox were detected and analyzed during 2013-2014 at Hefdahe Shahrivar Hospital, Mashhad, Iran. Overall, 52 failure modes were identified, with 25 being recognized as high-risk modes.

RESULTS

The results revealed that 48.5% of these errors fall into the care process type, 22.05% belong to the communicative type, 19.1% fall into the administrative type, and 10.2% are of the knowledge and skills type. Strategies were presented in the forms of acceptance (3.2%), control (90.3%), and elimination (6.4%).

CONCLUSION

The following actions are suggested for improving the process of using Entonox: Close supervision by the midwife, precise recording of all the stages of the process in the woman's medical record, the necessity of the presence of the anesthesiologist at the woman's bedside during labor, confirming the indications for use of Entonox, and close monitoring to ensure the safety of the gas cylinder guards.

It is no laughing matter: nitrous oxide formation in diesel engines and advances in its abatement over rhodium-based catalysts

N₂O appears as one of the undesired by-products in exhaust gases emitted from diesel engine aftertreatment systems, such as diesel oxidation catalysts (DOC), lean NO_x trap (LNT, also known as NO_x storage and reduction (NSR)) or selective catalytic reduction (NH₃-SCR and HC-SCR) and ammonia slip catalysts (ASC, AMOX, guard catalyst).

Recreational nitrous oxide use: Prevalence and risks

Nitrous oxide (N2O; laughing gas) is clinically used as a safe anesthetic (dentistry, ambulance, childbirth) and appreciated for its anti-anxiety effect. Since five years, recreational use of N2O is rapidly increasing especially in the dance and festival scene. In the UK, N2O is the second most popular recreational drug after cannabis. In most countries, nitrous oxide is a legal drug that is widely available and cheap. Last month prevalence of use among clubbers and ravers ranges between 40 and almost 80 percent. Following one inhalation, mostly from a balloon, a euphoric, pleasant, joyful, empathogenic and sometimes hallucinogenic effect is rapidly induced (within 10 s) and disappears within some minutes. Recreational N2O use is generally moderate with most users taking less than 10 balloons of N2O per episode and about 80% of the users having less than 10 episodes per year. Side effects of N2O include transient dizziness, dissociation, disorientation, loss of balance, impaired memory and cognition, and weakness in the legs. When intoxicated accidents like tripping and falling may occur. Some fatal accidents have been reported due to due to asphyxia (hypoxia). Heavy or sustained use of N2O inactivates vitamin B12, resulting in a functional vitamin B12 deficiency and initially causing numbness in fingers, which may further progress to peripheral neuropathy and megaloblastic anemia. N2O use does not seem to result in dependence. Considering the generally modest use of N2O and its relative safety, it is not necessary to take legal measures. However, (potential) users should be informed about the risk of vitamin B12-deficiency related neurological and hematological effects associated with heavy use.

Nitrous oxide for the management of labor pain: a systematic review

BACKGROUND

We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management.

METHODS

We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate.

RESULTS

We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited.

CONCLUSIONS

The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.

Analgesia for childbirth: modern insights into an age-old challenge and the quest for an ideal approach

SUMMARY It is widely recognized that childbirth may be the most painful experience in a woman’s lifetime and that women have a right to relief. There are many options, but the efficacy of only a few is supported by robust evidence. Many influences determine which method of pain relief is chosen, including social and cultural factors, availability, cost and personal preference. Due to human diversity and the differing perspectives of consumers, obstetric care providers and health administrators, there is no such thing as ‘an ideal approach’. In resource-rich societies, major advances in parturient safety and outcome flow from technique development and better monitoring. Greater awareness of the negative impact of untreated pain and of the relevance of genetic, cultural and social factors motivates research into better predictive models, novel therapies and optimization of existing methods.

Labor pain management other than neuraxial: what do we know and where do we go next?

Analgesia and coping with labor pain can prevent suffering during childbirth. Nonpharmacologic methods help women manage labor pain. Strong evidence is available for the efficacy of continuous one-to-one support from a woman trained to provide nonmedical care during labor, immersion in warm water during first-stage labor, and sterile water injected intracutaneously or subcutaneously at locations near a woman's lumbosacral spine to reduce back-labor pain. Sterile water injections also reduce the incidence of cesarean deliveries. Nitrous oxide labor analgesia is not potent, but helps women relax, gives them a sense of control, and reduces and distracts their perception of pain. It is inexpensive; can be administered and discontinued safely, simply, and quickly; has no adverse effects on the normal physiology and progress of labor; and does not require intensive monitoring or co-interventions. Parenteral opioids provide mild-to-moderate labor pain relief, but cause side effects. Although observational studies have found associations between maternal use of opioids and neonatal complications, little higher level evidence is available except that meperidine is associated with low Apgar scores. Patient-controlled intravenous administration of remifentanil provides better analgesia and satisfaction than other opioids, but can cause severe side effects; continuous monitoring of arterial oxygen saturation, anesthesia supervision, one-to-one nursing, and availability of oxygen are recommended. The demand for inexpensive, simple, safe but effective labor pain management for women will undoubtedly increase in places that lack wide access to it now.

Nitrous oxide as labor analgesia: clinical implications for nurses

A new interest in self-administered nitrous oxide for labor analgesia has emerged in recent years in the United States. It has been used widely in Europe for decades, with favorable results. The American College of Nurse-Midwives published a position statement in 2010 supporting the practice of self-administered nitrous oxide as an additional analgesia choice for laboring women. Recent literature on this subject has been directed toward midwives, obstetricians and/or anesthesiologists, with little emphasis for labor and delivery nurses. This article presents highlights of nursing care for women using self-administered nitrous oxide during labor and birth.

Inhaled analgesia for pain management in labour

BACKGROUND

Many women would like to have a choice in pain relief during labour and also would like to avoid invasive methods of pain management in labour. Inhaled analgesia during labour involves the self-administered inhalation of sub-anaesthetic concentrations of agents while the mother remains awake and her protective laryngeal reflexes remain intact. Most of the agents are easy to administer, can be started in less than a minute and become effective within a minute.

OBJECTIVES

To examine the effects of all modalities of inhaled analgesia on the mother and the newborn for mothers who planned to have a vaginal delivery.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2012), ClinicalTrials.gov, and Current Controlled Trials (2 June 2012), handsearched conference proceedings from the American Society of Clinical Anesthesia (from 1990 to 2011), contacted content experts and trialists and searched reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing inhaled analgesia with other inhaled analgesia or placebo or no treatment or other methods of non-pharmacological pain management in labour.

DATA COLLECTION AND ANALYSIS

Review authors independently assessed trials for eligibility, methodological quality and extracted all data. Data were double checked for accuracy.

MAIN RESULTS

Twenty-six studies, randomising 2959 women, were included in this review.Inhaled analgesia versus a different type of inhaled analgesia Pain relief was measured using a Visual Analogue Scale (VAS) from 0 to 100 mm where 100 corresponds to the most relief. Pain intensity was measured using a VAS from 0 to 100 mm, where 0 corresponds to no pain at all and 100 corresponds to the worst pain. The highest score for pain relief is the most positive in contrast to 'pain intensity' in which the higher score is more negative. Flurane derivatives were found to offer better pain relief than nitrous oxide in first stage of labour as measured by a lower pain intensity score (average mean difference (MD) 14.39, 95% confidence interval (CI) 4.41 to 24.37, three studies, 70 women), also a higher pain relief score for flurane derivatives compared with nitrous oxide (average MD -16.32, 95% CI -26.85 to -5.79, two studies, 70 women). Substantial heterogeneity was found in the analyses of pain intensity (P = 0.003) and in the analysis of pain relief (P = 0.002).These findings should be considered with caution because of the questionable design of the included cross-over trials. More nausea was found in the nitrous oxide group compared with the flurane derivatives group (risk ratio (RR) 6.60 95% CI 1.85 to 23.52, two studies, 98 women).Inhaled analgesia versus placebo or no treatment Placebo or no treatment was found to offer less pain relief compared to nitrous oxide (average RR 0.06, 95% CI 0.01 to 0.34, two studies, 310 women; MD -3.50, 95% CI -3.75 to -3.25, one study, 509 women). However, nitrous oxide resulted in more side effects for women such as nausea (RR 43.10, 95% CI 2.63 to 706.74, one study, 509 women), vomiting (RR 9.05, 95% CI 1.18 to 69.32, two studies, 619 women), dizziness (RR 113.98, 95% CI 7.09 to 1833.69, one study, 509 women) and drowsiness (RR 77.59, 95% CI 4.80 to 1254.96, one study, 509 women) when compared with placebo or no treatment.There were no significant differences found for any of the outcomes in the studies comparing one strength versus a different strength of inhaled analgesia, in studies comparing different delivery systems or in the study comparing inhaled analgesia with TENS.Due to lack of data, the following outcomes were not analysed within the review: sense of control; satisfaction with childbirth experience; effect on mother/baby interaction; breastfeeding; admission to special care baby unit; poor infant outcomes at long-term follow-up; or costs.

AUTHORS' CONCLUSIONS

Inhaled analgesia appears to be effective in reducing pain intensity and in giving pain relief in labour. However, substantial heterogeneity was detected for pain intensity. Furthermore, nitrous oxide appears to result in more side effects compared with flurane derivatives. Flurane derivatives result in more drowsiness when compared with nitrous oxide. When inhaled analgesia is compared with no treatment or placebo, nitrous oxide appears to result in even more side effects such as nausea, vomiting, dizziness and drowsiness. There is no evidence for differences for any of the outcomes comparing one strength verus a different strength of inhaled analgesia, comparing different delivery systems or comparing inhaled analgesia with TENS.