[Premixed 50% nitrous oxide and oxygen: theoretical recalls and practical modalities]

Botulinum Toxin Treatment of Adult Muscle Stem Cells from Children with Cerebral Palsy and hiPSC-Derived Neuromuscular Junctions

Botulinum neurotoxin type-A (BoNT) injections are commonly used as spasticity treatment in cerebral palsy (CP). Despite improved clinical outcomes, concerns regarding harmful effects on muscle morphology have been raised, and the BoNT effect on muscle stem cells remains not well defined. This study aims at clarifying the impact of BoNT on growing muscles (1) by analyzing the in vitro effect of BoNT on satellite cell (SC)-derived myoblasts and fibroblasts obtained from medial gastrocnemius microbiopsies collected in young BoNT-naïve children (t0) compared to age ranged typically developing children; (2) by following the effect of in vivo BoNT administration on these cells obtained from the same children with CP at 3 (t1) and 6 (t2) months post BoNT; (3) by determining the direct effect of a single and repeated in vitro BoNT treatment on neuromuscular junctions (NMJs) differentiated from hiPSCs. In vitro BoNT did not affect myogenic differentiation or collagen production. The fusion index significantly decreased in CP at t2 compared to t0. In NMJ cocultures, BoNT treatment caused axonal swelling and fragmentation. Repeated treatments impaired the autophagic-lysosomal system. Further studies are warranted to understand the long-term and collateral effects of BoNT in the muscles of children with CP.

The Use of a Fixed 50:50 Mixture of Nitrous Oxide and Oxygen to Reduce Lumbar Puncture-Induced Pain in the Emergency Department: A Randomized Controlled Trial

Lumbar puncture (LP) is stressful and often painful. We evaluated the efficacy of a fixed 50% nitrous oxide−oxygen mixture (50%N2O-O2) versus placebo to reduce immediate procedural pain and anxiety during LP performed in an emergency setting. We conducted a randomized controlled trial involving adults who needed a cerebrospinal fluid analysis in an emergency department. Patients were randomly assigned to inhale either 50%N2O-O2 or medical air. The primary endpoint, assessed using a numerical scale, was the maximum pain felt by the patient during the procedure and the maximum anxiety and satisfaction as secondary outcomes. Eighty-eight patients were randomized and analyzed (ITT). The maximal pain was 5.0 ± 2.9 for patients receiving air and 4.2 ± 3.0 for patients receiving 50%N2O-O2 (effect-size = −0.27 [−0.69; 0.14], p = 0.20). LP-induced anxiety was 4.7 ± 2.8 vs. 3.7 ± 3.7 (p = 0.13), and the proportion of patients with significant anxiety (score ≥ 4/10) was 72.7% vs. 50.0% (p = 0.03). Overall satisfaction was higher among patients receiving 50%N2O-O2 (7.4 ± 2.4 vs. 8.9 ± 1.6, p < 0.001). No serious adverse events were attributable to 50%N2O-O2 inhalation. Although inhalation of 50%N2O-O2 failed to reduce LP-induced pain in an emergency setting, it tended to reduce anxiety and significantly increased patient satisfaction.

Comparing the Effect of Gabapentin, Ketamine, Dexmedetomidine, and Entonox on Pain Control in Burn Wound Dressing

This study aimed to evaluate differences in the experience of pain, nausea, and vomiting, as well as the hemodynamic parameters including heart rate (HR) and blood pressure (BP) in burn patients across four pain treatment groups-i.e., gabapentin, ketamine, dexmedetomidine, and entonox. In a single blinded randomized comparative study, 25 burn patients with second- or third-degree burns between 20% and 50% of their body surface were assigned to different treatment groups by using block randomization, while keeping the investigator blind to the size of the block. We recorded demographics, the hemodynamics, adverse effects, and pain levels before the treatment and again 5, 10, 15, 30, 60, 120, 240, and 360 minutes postadministration of pain medication (after-treatment). Gabapentin ketamine, dexmedetomidine, and entonox had significant effects in treatment of pain in burn patients. Entonox had the best analgesic effect with the least adverse effects and hemodynamic changes. Gabapentin also had good pain management effects; however, it showed less desirable effects on hemodynamic variables. Entonox caused the least amount of hemodynamic changes and the least adverse reactions, but since the medication is delivered by a facemask it limited its application with our patients. Gabapentin offered good benefits but caused a gradual drop in BP and HR and had some unfavorable reactions. However, since it is administered orally and often is cheaper, it could be considered as the drug of choice.

A 50-50% mixture of nitrous oxide-oxygen in transrectal ultrasound-guided prostate biopsy: A randomized and prospective clinical trial

Introduction

Transrectal ultrasound-guided biopsy (TUSPB) is the standard method of diagnosis for prostate cancer, and although it is well tolerated by some patients, it presents a discomfort rate of 65 to 90%, which may be associated with pain. For convenience, it is agreed that a method of analgesia and sedation is necessary. For this purpose, this study aimed to evaluate the impact of inhalation of a 50–50% N₂O-O₂ gas mixture on pain intensity in these patients.

Material and methods

Randomized, double-blinded clinical trial, conducted at Antônio Pedro University Hospital (Hospital Universitário Antônio Pedro), Niterói, RJ, Brazil, containing two groups of 42 patients: a control (C) group, which received 100% oxygen inhalation, and a nitrous oxide (NO) group, which received inhalation of the 50–50% N₂O-O₂ mixture, self-administered during TUSPB. The pain intensity and degree of satisfaction were evaluated through a visual analogue scale (VAS), as was the frequency of adverse events.

Results

Eighty-four patients were included in the study, with 42 in each group. The mean pain intensity was lower in the NO group than in the C group [2.52 (0–10) vs 5.95 (0–10), p < 0.001], and the degree of satisfaction was higher in the NO group than in the C group (8.14 vs. 4.69, p < 0.001). The adverse effects were somnolence, dizziness, nausea, vomiting, discomfort and euphoria without differences between the groups.

Conclusion

The 50–50% N₂O-O₂ mixture was effective in reducing pain intensity and increasing the degree of satisfaction in TUSPB, with tolerable side effects.

[MEOPA use practices in a university hospital: Which conformity?]

INTRODUCTION

MEOPA (equimolar mixture of oxygen and nitrous oxide) is used for its analgesic and anxiolytic properties in order to obtain conscious sedation of the patient when performing painful care. It is subject to an enhanced pharmacovigilance and addictovigilance monitoring. In this context, it is important to dispose of hospital utilization data. This work aims to assess the compliance of the use of nitrous oxide regarding the recommendations of the summary of product characteristics, in a French university hospital (Nantes) and consider possible improvements.

MATERIALS AND METHODS

Transversal descriptive study, conducted in 2014 with all health professionals using MEOPA.

RESULTS

Two thousand thirty-four health professionals answered the questionnaire ; durations of administrations are in conformity and the premises are generally appropriate but almost 60% of professionals have the feeling of inhaling the drug. The systematization of the prescription (always or almost always prescribed for 67% of professionals) and traceability of use (always or almost always in the patient's file for 71% of professionals) are potential source of improvement, particularly since 18% of professional health reported "abuse demands" from patients.

CONCLUSION

The formation and information of health professionals are major issues of good use of nitrous oxide.

Fixed 50:50 mixture of nitrous oxide and oxygen to reduce lumbar-puncture-induced pain: a randomized controlled trial

BACKGROUND AND PURPOSE

Lumbar puncture (LP) has been frequently performed for more than a century. This procedure is still stressful and often painful. The aim of the study was to evaluate the efficacy of a fixed 50% nitrous oxide-oxygen mixture compared to placebo to reduce immediate procedural pain and anxiety during LP.

METHODS

A randomized controlled trial was conducted involving adults who needed a cerebrospinal fluid analysis. Patients were randomly assigned to inhale either a fixed 50% nitrous oxide-oxygen mixture (50% N₂ O-O₂ ) or medical air (22% O₂ -78% N₂ ). Cutaneous application of a eutectic mixture of local anaesthetics was systematically done and all LPs were performed with pencil point 25G needles (20G introducer needle). The primary end-point was the maximal pain level felt by the patient during the procedure, the maximal anxiety level being a secondary outcome, both measured using a numerical rating scale (0-10).

RESULTS

A total of 66 consecutive patients were randomized. The analysis was intention to treat. The maximal pain was 4.9 ± 2.7 for the 33 patients receiving air and 2.7 ± 2.7 for the 33 receiving 50% N₂ O-O₂ (P = 0.002). Similarly, the maximal LP-induced anxiety was 4.5 ± 3.1 vs. 2.6 ± 2.6 (P = 0.009), respectively. The number needed to treat to avoid one patient undergoing significant pain (pain score ≥ 4/10) was 2.75. Body mass index >25 kg/m² was significantly associated with higher pain intensity (P = 0.03). No serious adverse events were attributable to 50% N₂ O-O₂ inhalation.

CONCLUSIONS

Inhalation of a fixed 50% N₂ O-O₂ mixture is efficient to reduce LP-induced pain and anxiety.

[Renal denervation for resistant hypertension without general anesthesia: advantage of a MEOPA morphine protocol. Preliminary experience]

Renal denervation using the technique of radiofrequency is used only recently for the treatment of resistant hypertension. Normally, it is done under general anesthesia because the ablation point technique is painful. We suggest an alternative to general anesthesia comprising an association of morphin 0.1mg/kg IV to MEOPA (gas combining oxygen and azot protoxyd) delivered through an oxygen mask. Our series includes 12 consecutive patients treated between October 2011 and June 2013, the first five patients (group 1) have received only an hydroxizin and morphin sedation. Every five have felt the ablation painful, in two cases bearable pain (EVA<5), in three cases intense (EVA>5) pain leading to increasing doses of morphin, (total dose of 0.25mg/kg in two cases, 0.17mg in one case). For the seven following patients, a protocol including hydroxyzin, morphin and MEOPA given through a mask has been set up. Only one patient has felt a mild pain (EVA 5) leading to an increasing dose of morphin (total dose 0.17mg/kg). None of the six other patients has felt any pain during the procedure. The average dose of morphin is 0.17mg/kg in group 1, 0.11mg/kg in group 2. This is a preliminary study; if confirmed, it will allow a lot of hospitals without on-site possibilities of general anesthesia, to realize such procedures.

CONCLUSION

regarding pain, the procedure of renal ablation was well tolerated for six among seven patients receiving the association MEOPA and IV morphin. In contrast, in the five patients treated only with IV morphin, we observed a less good tolerance to pain and the need to increase the doses of IV morphin.

Analgesia effect of a fixed nitrous oxide/oxygen mixture on burn dressing pain: study protocol for a randomized controlled trial

Background

Procedural burn pain is the most intense acute pain and most likely type of burn injury pain to be undertreated due to the physician’s fear of the adverse effect of analgesia and lack of anesthetist present. At our institution, in most of the cases, local burn detersion and debridement were performed at the ward level without any analgesics. This article describes a study designed to test the analgesia effect of a fixed nitrous oxide/oxygen mixture on burn dressing pain.

Methods/design

The experiment was carried out in three centers. The patients were given a number from 1 to 240. A randomization list was produced by a statistician according to our preliminary study. Due to the severity of the pain suffered, ethically it was decided to help as many as possible, so patients given the letters A, B or C were treated using a canister with the appropriate letter containing preprepared nitrous oxide/oxygen mixture (NOOM). Those with D were given oxygen only, from an identical-looking canister labeled D. Neither patients, nor doctors, nor nurses, nor data collector knew what was in each canister, thus they were all blind. The nursing officer who implemented the intervention handed the doctors envelopes containing the patients’ name and allocation of A, B, C or D. Thus, patients receiving NOOM or oxygen were in the ratio 3:1. Parameters, including pain severity, blood pressure, heart rate, digital oxygen saturation and the Chinese version of the burn specific pain anxiety scale (C-BSPAS), were taken before, during and after dressing for each group. A video and audio record was taken individually for later communication coding and outcome analysis. Rescue analgesic was recorded.

Discussion

Based on the findings from our previous qualitative study that physician’s reluctance to order narcotic analgesia is due to its adverse effect and from our pilot experiment, this study aims to test the hypothesis that a fixed nitrous oxide/oxygen mixture will promote better burn dressing pain alleviation and outcomes. Analyses will focus on the effects of the experimental intervention on pain severity during dressing (primary outcomes); physiological parameters, C-BSPAS and acceptance of both health care professionals and patients (secondary outcomes). If this model of analgesia for burn pain management implemented by nurses proves successful, it could potentially be implemented widely in hospital and prehospital settings and improve patients’ satisfaction and quality of life.

Trial registration

(Clinical Trials Identifier: CHICTR-TRC11001690).

Nitrous oxide inhalation for transoesophageal echocardiography: an alternative to benzodiazepine sedation?

AIMS

Transoesophageal echocardiography (TEE) is usually performed using benzodiazepine sedation, which is a limiting factor for elderly patients or those with respiratory insufficiency. Kalinox, an equimolar mixture of nitrous oxide and oxygen, with no depressive respiratory action and fast reversible effects, seems ideally suited for performing TEE but has never been evaluated. The aim of the present study was to evaluate the TEE feasibility and efficiency using Kalinox compared with the standard care using benzodiazepine.

METHODS AND RESULTS

We prospectively enrolled 80 consecutive patients referred for TEE. In the 35 first patients, TEE was performed using intravenous benzodiazepine (Midazolam) and in the 45 last patients using Kalinox (nasal delivery). Pain and tolerance induced by the examination were evaluated on a 0-10 scale. Remembrance of the examination by the patient and quality of the TEE by the operator were also evaluated. All TEEs were performed by the same experienced operator. TEE duration was not different (6 +/- 3 vs. 7 +/- 4 min, respectively, P = 0.57). Patients in the Kalinox group felt TEE to be more difficult (P = 0.005) and remembered the procedure more clearly (P < 0.0001) but pain experience was not different (7 vs. 9% had a pain score >or=5, respectively, P = 0.75). Percentage of patients who agreed to have a second TEE if necessary was slightly lower (77 vs. 94%, respectively, P = 0.04). The operator judged TEE quality satisfactory in similar proportions (76 vs. 68%, respectively, P = 0.44).

CONCLUSION

These preliminary results show that TEE using Kalinox is feasible, provides similar pain relief despite more discomfort for the patient, and acceptable conditions for the operator. Thus, Kalinox use could be considered as an alternative to benzodiazepine sedation for patients intolerant to benzodiazepines such as elderly or respiratory-insufficient patients.

The analgesic effect of inhalational Entonox for extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is a non-invasive procedure that allows urinary stones to be fragmented using acoustic shock waves. The impact of the shock waves causes transient stinging pain at the entry site as well as deep visceral discomfort, requiring analgesia during the procedure. The objective of this study was to compare the clinical efficacy of Entonox and pethidine for pain relief during outpatient ESWL. We randomized 150 outpatients undergoing elective ESWL into three groups of 50 patients, each group receiving inhalational Entonox, intravenous pethidine, or inhalational compressed air during ESWL. Quantitative evaluation of pain was performed according to a visual analogue scale (VAS), before and after the intervention. Analysis of variance (ANOVA) and paired t tests were used to compare VAS scores in the three groups, before and after the intervention. Entonox and pethidine decreased the pain score significantly, while compressed air did not. There was no significant difference between pain relief by Entonox and pethidine. This study demonstrates for the first time that inhalational Entonox is an effective analgesic regimen for ESWL. Entonox can be regarded as an appropriate alternative to analgesics like opioids in relieving pain during ESWL.

[Pneumothorax following recreational inhalation of nitrous oxide]

CASE REPORT

A 21 year old man was admitted to hospital as an emergency complaining of left sided chest pain. Chest radiograph revealed a complete non compressive left-sided pneumothorax which resolved following thoracic drainage. A more detailed history revealed repeated and regular use of nitrous oxide by inhalation, for its consciousness-altering effect during rave parties.

DISCUSSION

The principal side effects occurring as a consequence of repeated exposures to nitrous oxide are haematological, neuropsychiatric and teratogenic. Rare cases of pneumothorax have been described associated with the use of nitrous oxide occurring as complications of anaesthesia or during laparoscopy where gas diffuses from the abdominal to the pleural cavity. Illicit use of nitrous oxide is rare and usually occurs in medical workers. Its spreading to the public may lead to accidents and unanticipated side effects.

CONCLUSION

Inhaled nitrous oxide can reveal asymptomatic pneumothorax by worsening it. The consequences can be dramatic in case of illicit use because of ignorance of side effects.