Use of the Schelin Catheter for transurethral intraprostatic anesthesia prior to Rezum treatment.

Minimally invasive surgery techniques (MIST) have become newly adopted in urological care.  Given this, new analgesic techniques are important in optimizing patient outcomes and resource management. Rezum treatment (RT) for BPH has emerged as a new MIST with excellent patient outcomes, including improving quality of life (QoL) and International Prostate Symptom Scores (IPSSs), while also preserving sexual function.  Currently, the standard analgesic approach for RT involves a peri-prostatic nerve block (PNB) using a transrectal ultrasound (TRUS) or systemic sedation anesthesia.  The TRUS approach is invasive, uncomfortable, and holds a risk of infection.  Additionally, alternative methods such as, inhaled methoxyflurane (Penthrox), nitric oxide, general anesthesia, as well as intravenous (IV) sedation pose safety risks or mandate the presence of an anesthesiology team.  Transurethral intraprostatic anesthesia (TUIA) using the Schelin Catheter (ProstaLund, Lund, Sweden) (SC) provides a new, non-invasive, and efficient technique for out-patient, office based Rezum procedures.  Through local administration of an analgesic around the prostate base, the SC has been shown to reduce pain, procedure times, and bleeding during MISTs.  Herein, we evaluated the analgesic efficacy of TUIA via the SC in a cohort of 10 patients undergoing in-patient RT for BPH.

Inhaled methoxyflurane (Penthrox) administration in dentistry as an alternative to nitrous oxide sedation: a review and feasibility study.

Methoxyflurane (MOF) as an agent for dental sedation has been used safely in Australasia for decades. The drug is now licensed for relief of pain associated with trauma and is being used during several medical outpatient procedures in the stead of traditional intravenous agents for sedation in the UK. Our aim was to analyse the safety and feasibility of the introduction of MOF as a drug for dental sedation in the UK community setting and assess its environmental impact. A literature review was conducted for available studies and a research audit of medical histories of patients that received nitrous oxide sedation in the previous year was carried out to assess suitability for MOF administration. The published literature shows MOF to be a safe drug for administration in the dental environment and local patients receiving nitrous oxide sedation are medically suitable for MOF administration. The advantages of considering MOF sedation are its environmental benefit and patient acceptability.

Environmental impact of low-dose methoxyflurane versus nitrous oxide for analgesia: how green is the 'green whistle'?

BACKGROUND: The NHS has the target of reducing its carbon emission by 80% by 2032. Part of its strategy is using pharmaceuticals with a less harmful impact on the environment. Nitrous oxide is currently used widely within the NHS. Nitrous oxide, if released into the atmosphere, has a significant environmental impact. Methoxyflurane, delivered through the Penthrox 'green whistle' device, is a short-acting analgesic and is thought to have a smaller environmental impact compared with nitrous oxide. METHODS: Life cycle impact assessment (LCIA) of all products and processes involved in the manufacture and use of Penthrox, using data from the manufacturer, online sources and LCIA inventory Ecoinvent. These data were analysed in OpenLCA. Impact data were compared with existing data on nitrous oxide and morphine sulfate. RESULTS: This LCIA found that Penthrox has a climate change effect of 0.84 kg carbon dioxide equivalent (CO2e). Raw materials and the production process contributed to majority of the impact of Penthrox across all categories with raw materials accounting for 34.40% of the total climate change impact. Penthrox has a climate change impact of 117.7 times less CO2e compared with Entonox. 7 mg of 100 mg/100 mL of intravenous morphine sulfate had a climate change effect of 0.01 kg CO2e. CONCLUSIONS: This LCIA has shown that the overall 'cradle-to-grave' environmental impact of Penthrox device is better than nitrous oxide when looking specifically at climate change impact. The climate change impact for an equivalent dose of intravenous morphine was even lower. Switching to the use of inhaled methoxyflurane instead of using nitrous oxide in certain clinical situations could help the NHS to reach its carbon emission reduction target.

Peri-prostatic nerve block using Clarius EC7 HD3 handheld ultrasound guidance.

Transrectal ultrasound (TRUS) is a common modality used during urological procedures that require real-time visualization of the prostate, such as prostate biopsy and peri-prostatic nerve blocks (PNB) for surgical procedures. Current practice for TRUS-guided PNB requires use of costly, fixed, and non-portable ultrasound machinery that can often limit workflow. The Clarius endocavity EC7 probe, a digital, handheld and pocket-sized endocavity ultrasound (US) device, is an alternative, portable technology which was recently shown to accurately visualize and measure prostate dimensions and volume. Moreover, in recent years, there has been a renaissance of office-based treatments for minimally invasive surgical therapies (MIST) for the treatment of benign prostate hyperplasia (BPH). More specifically, the Rezum procedure has been demonstrated to offer men a short, outpatient therapy with excellent 5-year outcomes in durability and preservation of antegrade ejaculation. While other anesthetic techniques have been described for Rezum, including inhaled methoxyflurane (Penthrox), nitrous oxide, IV sedation and general anesthesia (which often mandate the presence of an anesthesiology team), US-guided local blocks offer the urologist an independent method for pain management. While most urologists may not have direct access to expensive, cart-based ultrasound systems, point of care ultrasound (POCUS) technology, such as Clarius (Vancouver, BC, Canada) and Butterfly (Butterfly Network, Inc, Guilford, CT, USA), can provide high-resolution imaging in combination with smart phone technology. Herein, we sought to describe the technique for using Clarius EC7 for TRUS-guided PNB and its use in urological application with the Rezum BPH procedure.

Comparison of three regimens with inhalational methoxyflurane versus intranasal fentanyl versus intravenous morphine in pre-hospital acute pain management: study protocol for a randomized controlled trial (PreMeFen).

BACKGROUND: Pre-hospital pain management has traditionally been performed with intravenous (IV) morphine, but oligoanalgesia remain a recognized problem. Pain reduction is essential for patient satisfaction and is regarded as a measure of successful treatment. We aim to establish whether non-invasive methods such as inhalation of methoxyflurane is non-inferior to intranasal fentanyl or non-inferior to the well-known IV morphine in the pre-hospital treatment of acute pain. METHOD/DESIGN: The PreMeFen study is a phase three, three-armed, randomized, controlled, non-inferiority trial to compare three regimens of analgesics: inhalation of methoxyflurane and intranasal (IN) fentanyl versus IV morphine. It is an open-label trial with a 1:1:1 randomization to the three treatment groups. The primary endpoint is the change in pain numeric rating scale (NRS) (0-10) from baseline to 10 min after start of investigational medicinal product administration (IMP). The non-inferiority margin was set to 1.3, and a sample size of 270 patients per protocol (90 in each treatment arm) will detect this difference with 90% power. DISCUSSION: We chose a study design with comparison of analgesic regimens rather than fixed doses because of the substantial differences in drug characteristics and for the results to be relevant to inform policymakers in the pre-hospital setting. We recognize that easier administration of analgesics will lead to better pain management for many patients if the regimens are as good as the existing, and hence, we chose a non-inferiority design. The primary endpoint, the change in pain (NRS) after 10 min, is set to address the immediate need of pain reduction for patients with acute prehospital pain. On a later stage, more analgesic methods are often available. PreMeFen is a non-inferiority randomized controlled trial comparing three analgesic regimens aiming to establish whether inhalation of methoxyflurane or intranasal fentanyl is as good as IV morphine for fast reduction of acute pain in the prehospital setting.

Real world safety of methoxyflurane analgesia in the emergency setting: a comparative hybrid prospective-retrospective post-authorisation safety study.

BACKGROUND: Low-dose analgesic methoxyflurane (Penthrox®) was approved in Europe for emergency relief of moderate to severe pain in conscious adults with trauma in 2015. A comparative post-authorisation safety study (PASS) was conducted to assess the risk of hepatotoxicity and nephrotoxicity with methoxyflurane during routine clinical practice. METHODS: This was a comparative hybrid prospective-retrospective cohort study. The comparative cohorts consisted of adults who were given methoxyflurane (methoxyflurane cohort) or another analgesic (concurrent cohort) routinely used for moderate to severe trauma and associated pain in the emergency setting (ambulance and Emergency Department) in the UK between December 2016 and November 2018. Hepatic and renal events were captured in the ensuing 12 weeks. A blinded clinical adjudication committee assessed events. A historical comparator cohort (non-concurrent cohort) was identified from patients with fractures in the English Hospital Episode Statistics (HES) accident and emergency database from November 2013 and November 2015 (before commercial launch of methoxyflurane). Hepatic and renal events were captured in the ensuing 12 weeks via linkage with the Clinical Practice Research Datalink (CPRD) and HES hospital admissions databases. RESULTS: Overall, 1,236, 1,101 and 45,112 patients were analysed in the methoxyflurane, concurrent and non-concurrent comparator cohorts respectively. There was no significant difference in hepatic events between the methoxyflurane and concurrent cohorts (1.9% vs. 3.0%, P = 0.079) or between the methoxyflurane and non-concurrent cohorts (1.9% vs. 2.5%, P = 0.192). Renal events were significantly less common in the methoxyflurane cohort than in the concurrent cohort (2.3% vs. 5.6%, P < 0.001). For methoxyflurane versus non-concurrent cohort the lower occurrence of renal events (2.3% vs. 3.2%, P = 0.070) was not statistically significant. Multivariable adjustment did not change these associations. CONCLUSIONS: Methoxyflurane administration was not associated with an increased risk of hepatotoxicity or nephrotoxicity compared with other routinely administered analgesics and was associated with a reduced risk of nephrotoxicity compared with other routinely administered analgesics. TRIAL REGISTRATION: Study registered in the EU PAS Register (ENCEPP/SDPP/13040).

Assessing the potential climate impact of anaesthetic gases.

There is increasing concern within the health-care community about the role care delivery plays in environmental degradation, sparking research into how to reduce pollution from clinical practice. Inhaled anaesthetics is a particular research area of interest for two reasons. First, several gases are potent greenhouse gases, and waste gas is mostly emitted directly to the environment. Second, there are options to reduce gas waste and substitute medications and procedures with fewer embodied emissions while delivering high-quality care. Performance improvements are contingent on a proper understanding of the emission estimates and climate metrics used to ensure consistent application in guiding mitigation strategies and accounting at various scales. We review the current literature on the environmental impact and the estimation of the potential climate forcing of common inhaled anaesthetic drugs: desflurane, sevoflurane, isoflurane, methoxyflurane, and nitrous oxide.

Pain Self-Management with Inhaled Methoxyflurane by Emergency Department Trauma Patients: A Prospective, Interventional, Single-Center Study.

The coronavirus disease 2019 (COVID-19) pandemic has led to overcrowding in many emergency departments (EDs). The present single-center, prospective, interventional study (conducted at Bichat University Medical Center (Paris, France)) was designed to assess the impact of self-administered, inhaled, low-dose methoxyflurane on trauma pain in a pre-ED fast-track zone dedicated to the management of lower-acuity non-COVID-19 patients. In the first phase of the study, the control group consisted of patients with mild-to-moderate trauma pain, for whom the triage nurse initiated pain management (based on the World Health Organization (WHO)'s analgesic ladder). In the second phase, the intervention group consisted of similar patients who self-administered methoxyflurane as an adjuvant to the standard analgesic ladder. The primary endpoint was the numerical pain rating scale (NPRS) score (from 0 to 10) recorded at different time points during the patient's care (T0: arrival in the ED, T1: exit from the triage box, T2: in the radiology department, T3: clinical examination, and T4: discharge from the ED). The level of agreement between the NPRS and the WHO analgesic ladder was assessed by the calculation of Cohen's kappa. Pairwise comparisons of continuous variables were performed with Student's t-test or a non-parametric Mann-Whitney U test. Changes over time in the NPRS were analyzed in an analysis of variance (with Scheffe's post hoc test if a pairwise comparison was significant) or a non-parametric Kruskal-Wallis H test. In all, 268 and 252 patients were included in the control and intervention groups, respectively. The two groups had similar characteristics. The level of agreement between the NPRS score and the analgesic ladder was high in both the control and intervention groups (Cohen's kappa: 0.74 and 0.70, respectively). The NPRS score decreased significantly between T0 and T4 in both groups (p < 0.001), but the decrease between T2 and T4 was significantly greater in the intervention group (p < 0.001). The proportion of patients still in pain on discharge was significantly lower in the intervention group than in the control group (p = 0.001). In conclusion, a combination of self-administered methoxyflurane and the WHO analgesic ladder improves pain management in the ED.

Use of ketamine wafer for pain management by volunteer emergency medical technicians in rural Western Australia.

OBJECTIVE: To describe the use of sublingual ketamine wafers administered by volunteer emergency medical technicians (EMTs) for pain management to patients in rural Western Australia (WA). METHODS: This retrospective cohort study included patients older than 12 years who were attended by volunteer EMTs in Esperance, Lancelin and Kalbarri, WA and received analgesic medications from 2018 to 2021. Patients who received ketamine wafers with/without other analgesics were compared to (i) patients who received only oral paracetamol and (ii) patients who received inhalational methoxyflurane without ketamine wafers with/without paracetamol. RESULTS: The present study included 826 patients, among whom 149 patients received ketamine wafer with/without other analgesics, 82 paracetamol only and 595 methoxyflurane with/without paracetamol. Patients who received ketamine wafers were younger (median age 49 years vs 54 years for the paracetamol group vs 58 years for the methoxyflurane group), required a longer median transport interval (56 min vs 20 min vs 8 min), trauma-related (73% vs 35% vs 54%), and presented higher median initial pain score (9 vs 3 vs 8 out of 10) than those who received paracetamol and those who received methoxyflurane, respectively. Eight in the ketamine wafers group (5.4%) had a record of nausea/vomiting after the administration of ketamine wafers. CONCLUSIONS: Sublingual ketamine wafer was administered by volunteer EMTs without any evidence of major adverse events in rural WA and deemed useful as an additional pain management option when long transport to hospital was needed. No other symptoms that may be associated with the use of ketamine were recorded.

Ambulance nurses' experiences of pain management with Penthrox® in Swedish ambulance care: A mixed method study.

BACKGROUND: Methoxyflurane (MTX) is an inhalation agent that has several potential benefits for limiting various types of pain in ambulance care. AIM: To elucidate how ambulance nurses experience the characteristics of MTX in an ambulance care setting. METHOD: This cross-sectional study applied a mixed-methods approach, using a questionnaire together with complementary interviews. The questionnaire survey was analyzed using descriptive statistics (10-point Likert scale and question index values [Q-IV], range: 0-1.0). The interviews were analyzed using directed content analysis. Study results were reported following the STROBE statement. RESULTS: The ambulance nurses' overall general satisfaction with the MTX concept had a median of 7.0 (IQR 5-8), corresponding to a mean Q-IV of 0.84 (very good experience). The qualitative part was divided into three categories: sense of security, patient participation, and general usefulness. The results revealed varying experiences of usefulness, including pain-relieving effect and the possibility of patient participation. The perceived strong odor of MTX seemed to concern the ambulance nurses and their patients. CONCLUSION: In general, MTX was experienced as a safe and effective analgesic. However, the experiences of the overall usefulness varied, particularly since the product had a perceived strong odor. Increasing knowledge of using MTX, could likely increase the overall usefulness.

Literature review on the use of methoxyflurane in the management of pain in cancer-related procedures.

INTRODUCTION: Self-administered methoxyflurane, also known as Penthrox, at a sub-anesthetic dose is a short-term, fast-acting, and safe analgesic that may provide suitable pain relief for cancer patients. This review aims to compile the existing evidence on methoxyflurane and its efficacy in reducing pain during cancer-related procedures. METHODS: A literature search was conducted through OVID Medline and Embase. The search was limited to articles published between 2012 and 2021 and studies were included if they assessed the efficacy of methoxyflurane to reduce pain in cancer-related procedures. All types of cancer were included. RESULTS: The literature search yielded seven studies published between 2012 and 2021. The studies analyzed assessed methoxyflurane use in prostate biopsy, colonoscopy, removal of brachytherapy rods, and bone marrow biopsy. Various research designs were employed, including three randomized controlled trials, two prospective observational studies, one retrospective, and one non-randomized controlled trial. In all, methoxyflurane has a demonstrated ability to reduce pain in these procedures. CONCLUSION: In the limited studies available in evaluating the efficacy of methoxyflurane for reducing procedural pain during cancer-related procedures, all have demonstrated clinical equivalency or superiority. Pain relief appears to be equivalent however methoxyflurane overcomes the standard limitations of respiratory sedation and has demonstrated quicker procedural recovery times than traditional sedation methods. The accumulated data to date supports the use of methoxyflurane which can supplement or supplant current methods of analgesia in cancer-related procedures.

How I Do It: Penthrox in Urology.

Penthrox is a portable handheld inhaler that delivers a low dose of methoxyflurane - an anesthetic with analgesic effects, rapid onset of action, and a favorable side-effect profile. It has been widely used for acute pain management in Australia for the past 40 years. Currently, it is approved for use in over 55 countries, including Canada. Prospective randomized studies highlight Penthrox analgesic effectiveness and safety profile for emergency, prehospital and outpatient settings. In addition, the use of multimodal analgesia, specifically Penthrox, can play an important role in the analgesic management of urological procedures, such as prostatic biopsies and office-based minimally invasive surgical therapies. Herein readers will familiarize themselves with Penthrox, significant studies, and technique used for outpatient urological procedures.

A narrative review on pain control interventions for non-surgical pleural procedures.

Pleural diseases are common and frequently result in disabling symptoms, impaired health-related quality of life and hospitalisation. Both diagnosis and management often require pleural procedures and despite a variety of pain control strategies available for clinicians to employ, many procedures are still complicated by pain and discomfort. This can interfere with procedure success and can limit patient satisfaction. This review examines the evidence for pain control strategies for people undergoing non-surgical pleural procedures. A systematic literature search was undertaken to identify published studies examining different pain control strategies including pharmacological (sedatives, paravertebral blocks, erector spinae blocks, intrapleural anaesthesia, epidural anaesthesia, local anaesthetic, methoxyflurane, non-steroidal anti-inflammatory drugs [NSAIDs], opioids) and non-pharmacological measures (transcutaneous electric nerve stimulation [TENS], cold application and changes to the intervention or technique). Current literature is limited by heterogeneous study design, small participant numbers and use of different endpoints. Strategies that were more effective than placebo or standard care at improving pain included intrapleural local anaesthesia, paravertebral blocks, NSAIDs, small-bore intercostal catheters (ICC), cold application and TENS. Inhaled methoxyflurane, thoracic epidural anaesthesia and erector spinae blocks may also be useful approaches but require further evaluation to determine their roles in routine non-surgical pleural procedures. Future research should utilise reliable and repeatable study designs and reach consensus in endpoints to allow comparability between findings and thus provide the evidence-base to achieve standardisation of pain management approaches.

Efficacy and Safety of Methoxyflurane for Treatment of Acute Traumatic Pain by EMTs during Alpine Rescue Operations: The "PainDrop" Trial.

Background: Treatment of acute traumatic pain is a core task for mountain rescue services. Intravenous access, however, is often difficult, and the vast majority of missions are carried out without a physician at the scene. The spectrum of analgesics available for use by non-physician personnel is limited. Inhaled analgesics, such as methoxyflurane, might prove useful, but currently no data exist on their application by non-physicians in the alpine setting.Methods: This prospective observational alpine field study was conducted over a period of 15 months. Patients suffering traumatic injuries with moderate to severe pain (pain score ≥ 5) after downhill bike accidents in the Tyrol mountains (1,362 m to 2,666 m above sea level) were enrolled. Teams of four mountain rescue service members, one of them a trained EMT, treated the patients with 3 ml of methoxyflurane by inhaler. We measured efficacy as reduction in pain from baseline to 15 minutes after treatment on a numerical rating scale. Safety was assessed by change in vital signs or occurrence of side-effects. Sample-size calculations were based on the efficacy outcome and yielded a need for 20 patients at a power of 0.8.Results: From June 29, 2020 to September 30, 2021, a total of 20 patients (two females; mean age 37 years) were included. The mean initial pain score was 7.2 (SD 1.0) points. After 15 minutes, pain was significantly reduced by a mean of 2.9 (SD 1.4) points. No major adverse events or relevant changes in vital signs were observed.Conclusion: The use of methoxyflurane by EMTs during alpine rescue operations in our study proved to be safe and efficient. We observed no reduction in the efficacy of the inhaler device at moderate altitude.

Penthrox enables quicker management of fractures, dislocations and more: learning lessons from expedited care of trauma patients during the COVID-19 pandemic.

INTRODUCTION: Methoxyflurane is an historical anaesthetic agent that has undergone a renaissance with the introduction of a smaller dose in a handheld 'Penthrox' device. The benefits of Penthrox include its ease of use, with disposable individual packets, and the need for less monitoring and staff, when compared with deeper sedation. The literature acknowledges its use for analgesia and in the management of anterior shoulder dislocation but in no other procedural orthopaedic circumstance. METHODS: Following institutional approval, we undertook a retrospective review of all incidences of Penthrox use to facilitate minor procedures within a 2-month period starting 24 March 2020. Time to procedure and success were recorded using the surrogate markers of patient attendance and x-Ray occurrence times. RESULTS: Some 101 Penthrox doses were given to 89 patients over 97 unique episodes between 24 March and 26 May 2020. No complications were recorded following the use of Penthrox during this period. Patient demographics were explored. Fracture manipulations and casting (n=54) had a 100% success rate in achieving adequate and safe reduction. Joint dislocations (n=34) were treated with varying success. Native elbow dislocations were reduced most successfully (4/4, 100%). Native shoulder dislocations were seen in 17 patients and successful relocation was seen in 11 cases, giving a success rate of 65%. CONCLUSIONS: This is the first study, outside anterior shoulder dislocations, to report on the efficacy of Penthrox within emergent orthopaedic scenarios. We have demonstrated Penthrox to be a safe tool for helping to manage trauma procedures in the emergency department.

Efficacy and safety of methoxyflurane (Penthrox) for pain control during water vapor thermal therapy (Rezum) for benign prostatic enlargement.

INTRODUCTION: The safety and efficacy of low dose methoxyflurane disposable inhaler (Penthrox) was assessed in this study of men undergoing Rezum water vapor thermal therapy (WVTT). MATERIAL AND METHODS: An open-labeled, single-center study was conducted to demonstrate the safety and efficacy of using methoxyflurane inhaler during a Rezum procedure. Patients assessed current pain intensity using a 10-point Visual Analog Scale (VAS) of Pain at 4 timepoints including (1) before any medication, (2) initially after insertion of the rigid cystoscope and before any Rezum treatment, (3) immediately after final injection of Rezum treatment and (4) at discharge. Patients were asked to fill out the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4) and one question about pain relief at discharge. Treating physician also completed the TSQM 1.4. RESULTS: Ten patients were recruited. Median prostate volume was 53.4 cc (range 24-158 cc). Patients received a median of 10.5 Rezum injections, with a median procedure time of 4.5 minutes. Median VAS scores were 0, 0.1, 0 (primary efficacy outcome) and 0 (out of scale of 10) at the 4 timepoints, respectively. TSQM scores on effectiveness, side effects, convenience and global median satisfaction rated by patients were respectively 69.4, 100.0, 77.8 and 82.1 (out of scale of 100). Treatment satisfaction on pain relief was rated as 4.0 (very good). There were no observed adverse events. CONCLUSIONS: Methoxyflurane inhaler (Penthrox) was low cost, rapid, feasible and easy to administer as a pain management strategy for Rezum therapy. Further data from a larger comparative study will be conducted.

Prevalence and Perinatal Outcomes Following In Utero Exposure to Prehospital Emergency Methoxyflurane: A 17-Year Retrospective Cohort Study.

OBJECTIVE: To examine the prevalence of exposure and perinatal outcomes associated with in utero exposure to methoxyflurane. DESIGN, SETTING AND POPULATION: Whole-population ambulance data in Western Australia (WA) were linked to the statutory perinatal data collection to identify pregnant women transferred by ambulance between 2000 and 2016. The proportion of neonates in WA exposed to methoxyflurane, fentanyl or no analgesia during an ambulance transfer was calculated. Perinatal outcomes of pregnancies exposed to methoxyflurane (n=1579) were compared to those exposed to fentanyl (n=203) or no analgesia (n=10524) using multivariable logistic regression modelling. Perinatal outcomes were considered overall and by trimester of exposure. MAIN OUTCOME MEASURES: Primary outcomes were the prevalence of in utero methoxyflurane exposure and Apgar score on the day of delivery. RESULTS: In the study period, 0.4% of all neonates born in WA were exposed to methoxyflurane in utero. Methoxyflurane exposure on the day of delivery (n=657) was not associated with an increased likelihood of a low Apgar score at five minutes compared with no analgesia (n=2667) (OR 1.23, 95% CI 0.91-1.67). Whereas fentanyl exposure (n=22) was associated with an increased likelihood of low Apgar score compared with methoxyflurane (OR 3.67, 95% CI 1.18-11.48). CONCLUSIONS: Methoxyflurane is commonly used by ambulance services to treat pain in pregnant women in WA. While not recommended for use in pregnancy, pregnancies exposed to methoxyflurane did not have an increased risk of adverse perinatal outcomes in this study.

Evaluation of the effectiveness and costs of inhaled methoxyflurane versus usual analgesia for prehospital injury and trauma: non-randomised clinical study.

BACKGROUND: We aimed to investigate clinical benefits and economic costs of inhaled methoxyflurane when used by ambulance staff for prehospital emergency patients with trauma. Comparison is to usual analgesic practice (UAP) in the UK in which patient records were selected if treatment had been with Entonox® or intravenous morphine or intravenous paracetamol. METHODS: Over a 12-month evaluation period, verbal numerical pain scores (VNPS) were gathered from adults with moderate to severe trauma pain attended by ambulance staff trained in administering and supplied with methoxyflurane. Control VNPS were obtained from ambulance database records of UAP in similar patients for the same period. Statistical modelling enabled comparisons of methoxyflurane to UAP, where we employed an Ordered Probit panel regression model for pain, linked by observational rules to VNPS. RESULTS: Overall, 96 trained paramedics and technicians from the East Midlands Ambulance Service NHS Trust (EMAS) prepared 510 doses of methoxyflurane for administration to a total of 483 patients. Comparison data extracted from the EMAS database of UAP episodes involved: 753 patients using Entonox®, 802 patients using intravenous morphine, and 278 patients using intravenous paracetamol. Modelling results included demonstration of faster pain relief with inhaled methoxyflurane (all p-values < 0.001). Methoxyflurane's time to achieve maximum pain relief was estimated to be significantly shorter: 26.4 min (95%CI 25.0-27.8) versus Entonox® 44.4 min (95%CI 39.5-49.3); 26.5 min (95%CI 25.0-27.9) versus intravenous morphine 41.8 min (95%CI 38.9-44.7); 26.5 min (95%CI 25.1-28.0) versus intravenous paracetamol 40.8 (95%CI 34.7-46.9). Scenario analyses showed that durations spent in severe pain were significantly less for methoxyflurane. Costing scenarios showed the added benefits of methoxyflurane were achieved at higher cost, eg versus Entonox® the additional cost per treated patient was estimated to be £12.30. CONCLUSION: When administered to adults with moderate or severe pain due to trauma inhaled methoxyflurane reduced pain more rapidly and to a greater extent than Entonox® and parenteral analgesics. Inclusion of inhaled methoxyflurane to the suite of prehospital analgesics provides a clinically useful addition, but one that is costlier per treated patient.

Trauma pain management in the emergency department: use of methoxyflurane as a patient-administered analgesic.

Evidence suggests that pain is highly prevalent among patients with traumatic injuries who attend emergency departments (EDs), yet accurate assessment and management of patients with acute pain can be challenging in this setting. Effective and rapid pain management is beneficial for patients and can support timely discharge from the ED, which is particularly important in the context of the coronavirus disease 2019 (COVID-19) pandemic. This article describes a service development project that introduced the use of a patient-administered analgesic, methoxyflurane, for patients with traumatic injuries with moderate to severe pain in one ED. The author outlines the benefits and rationale for using methoxyflurane as a first-line analgesic in this patient group and describes the main elements of training sessions for emergency nurses and other ED clinicians in the administration and supervision of patient-administered methoxyflurane.

Usability and effectiveness of inhaled methoxyflurane for prehospital analgesia - a prospective, observational study.

BACKGROUND: Pain relief in the prehospital setting is often insufficient, as the administration of potent intravenous analgesic drugs is mostly reserved to physicians. In Australia, inhaled methoxyflurane has been in routine use by paramedics for decades, but experience in Central European countries is lacking. Thus, we aimed to assess whether user friendliness and effectiveness of inhaled methoxyflurane as sole analgesic match the specific capabilities of local ground and air-based EMS systems in Austria. METHODS: Observational study in adult trauma patients (e.g. dislocations, fracture or low back pain following minor trauma) with moderate to severe pain (numeric rating scale [NRS] ≥4). Included patients received a Penthrop® inhaler containing 3 mL of methoxyflurane (maximum use 30 min). When pain relief was considered insufficient (NRS reduction < 3 after 10 min), intravenous analgesics were administered by an emergency physician. The primary endpoint was effectiveness of methoxyflurane as sole analgesic for transport of patients. Secondary endpoints were user friendliness (EMS personell), time to pain relief, vital parameters, side effects, and satisfaction of patients. RESULTS: Median numeric pain rating was 8.0 (7.0-8.0) in 109 patients. Sufficient analgesia (reduction of NRS ≥3) was achieved by inhaled methoxyflurane alone in 67 patients (61%). The analgesic effect was progressively better with increasing age. Side effects were frequent (n = 58, 53%) but mild. User satisfaction was scored as very good when pain relief was sufficient, but fair in patients without benefit. Technical problems were observed in 16 cases (14.7%), mainly related to filling of the inhaler. In every fifth use, the fruity smell of methoxyflurane was experienced as unpleasant. No negative effects on vital signs were observed. CONCLUSION: In prehospital use, inhaled methoxyflurane as sole analgesic is effective for transport of trauma patients (62%) with moderate to severe pain. Older patients benefit especially from inhaled methoxyflurane. Side effects are mild and vital parameters unaffected. Thus, inhaled methoxyflurane could be a valuable device for non-physician EMS personnel rescue services also in the central Europe region.