Nitrous oxide in emergency medicine

Wilderness Medical Society Clinical Practice Guidelines for the Treatment of Acute Pain in Austere Environments: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the "WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments" published in Wilderness & Environmental Medicine 2014; 25:41-49.

Support-vector classification of low-dose nitrous oxide administration with multi-channel EEG power spectra

Support-vector machines (SVMs) can potentially improve patient monitoring during nitrous oxide anaesthesia. By elucidating the effects of low-dose nitrous oxide on the power spectra of multi-channel EEG recordings, we quantified the degree to which these effects generalise across participants. In this single-blind, cross-over study, 32-channel EEG was recorded from 12 healthy participants exposed to 0, 20, 30 and 40% end-tidal nitrous oxide. Features of the delta-, theta-, alpha- and beta-band power were used within a 12-fold, participant-wise cross-validation framework to train and test two SVMs: (1) binary SVM classifying EEG during 0 or 40% exposure (chance = 50%); (2) multi-class SVM classifying EEG during 0, 20, 30 or 40% exposure (chance = 25%). Both the binary (accuracy 92%) and the multi-class (accuracy 52%) SVMs classified EEG recordings at rates significantly better than chance (p < 0.001 and p = 0.01, respectively). To determine the relative importance of frequency band features for classification accuracy, we systematically removed features before re-training and re-testing the SVMs. This showed the relative importance of decreased delta power and the frontal region. SVM classification identified that the most important effects of nitrous oxide were found in the delta band in the frontal electrodes that was consistent between participants. Furthermore, support-vector classification of nitrous oxide dosage is a promising method that might be used to improve patient monitoring during nitrous oxide anaesthesia.

Nitrous oxide tank cold burn to the forearm: a case study and discussion of the literature

Nitrous oxide (N 2 O) has become one of the most popular recreational drugs in Europe. While N 2 O is often used in medical settings as an analgesic and anaesthetic agent, its recreational use was documented many years before its introduction into clinical practice. The desired effects from inhaling N 2 O for recreational purposes include rapid feelings of relaxation, calmness and euphoria, which can be accompanied by giddiness and laughter. There are various adverse effects associated with N 2 O use, including headache, nausea, vomiting, drowsiness and the development of permanent neurological damage. Furthermore, its use is associated with cold burns and road accidents. This article details the case of a patient who sustained an N 2 O tank burn to his forearm from recreational use. It also discusses the prevalence, legal status and adverse effects of N 2 O use as well as the pathophysiology and management of cold burn injuries.

An Electroencephalogram Metric of Temporal Complexity Tracks Psychometric Impairment Caused by Low-dose Nitrous Oxide

BACKGROUND

Nitrous oxide produces non-γ-aminobutyric acid sedation and psychometric impairment and can be used as scientific model for understanding mechanisms of progressive cognitive disturbances. Temporal complexity of the electroencephalogram may be a sensitive indicator of these effects. This study measured psychometric performance and the temporal complexity of the electroencephalogram in participants breathing low-dose nitrous oxide.

METHODS

In random order, 20, 30, and 40% end-tidal nitrous oxide was administered to 12 participants while recording 32-channel electroencephalogram and psychometric function. A novel metric quantifying the spatial distribution of temporal electroencephalogram complexity, comprised of (1) absolute cross-correlation calculated between consecutive 0.25-s time samples; 2) binarizing these cross-correlation matrices using the median of all channels as threshold; (3) using quantitative recurrence analysis, the complexity in temporal changes calculated by the Shannon entropy of the probability distribution of the diagonal line lengths; and (4) overall spatial extent and intensity of brain complexity, was quantified by calculating median temporal complexity of channels whose complexities were above 1 at baseline. This region approximately overlay the brain's default mode network, so this summary statistic was termed "default-mode-network complexity."

RESULTS

Nitrous oxide concentration correlated with psychometric impairment (r = 0.50, P < 0.001). Baseline regional electroencephalogram complexity at midline was greater than in lateral temporal channels (1.33 ± 0.14 bits vs. 0.81 ± 0.12 bits, P < 0.001). A dose of 40% N2O decreased midline (mean difference [95% CI], 0.20 bits [0.09 to 0.31], P = 0.002) and prefrontal electroencephalogram complexity (mean difference [95% CI], 0.17 bits [0.08 to 0.27], P = 0.002). The lateral temporal region did not change significantly (mean difference [95% CI], 0.14 bits [-0.03 to 0.30], P = 0.100). Default-mode-network complexity correlated with N2O concentration (r = -0.55, P < 0.001). A default-mode-network complexity mixed-effects model correlated with psychometric impairment (r2 = 0.67; receiver operating characteristic area [95% CI], 0.72 [0.59 to 0.85], P < 0.001).

CONCLUSIONS

Temporal complexity decreased most markedly in medial cortical regions during low-dose nitrous oxide exposures, and this change tracked psychometric impairment.

EDITOR’S PERSPECTIVE

Nitrous Oxide Compared With Intravenous Sedation for Second-Trimester Abortion: A Randomized Controlled Trial

OBJECTIVE

To assess whether inhaled nitrous oxide is noninferior to intravenous (IV) sedation for pain control during outpatient surgical abortion between 12 and 16 weeks of gestation.

METHODS

We enrolled women undergoing surgical abortion at 12-16 weeks of gestation into a multisite, double-blind clinical trial. Participants were randomized to sedation with nitrous oxide (70% nitrous/30% oxygen) or IV fentanyl (100 micrograms) and midazolam (2 mg). Paracervical block was administered to both groups. The primary outcome measure was immediate postabortion recall of maximum pain on a 100-mm visual analog scale.

RESULTS

Between August 2016 and March 2017, we assessed 170 women for eligibility and enrolled 39, 19 in the nitrous group and 20 in the IV sedation group. Seven participants in the nitrous group (36.8%) required conversion to IV sedation for inadequate pain control. No participants in the IV sedation group required additional medication. The proportion of women requiring additional pain control in the nitrous group exceeded our predefined stopping rule. Intention-to-treat analysis demonstrated that immediate postabortion visual analog scale pain scores were lower by 20.1 mm (95% CI 1.6-38.6) in women randomized to IV sedation than in women randomized to nitrous.

CONCLUSION

Intravenous sedation is a better choice than inhaled nitrous oxide for pain control in second-trimester abortion.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02755090.

Guidelines for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures

The safe sedation of children for procedures requires a systematic approach that includes the following: no administration of sedating medication without the safety net of medical/dental supervision, careful presedation evaluation for underlying medical or surgical conditions that would place the child at increased risk from sedating medications, appropriate fasting for elective procedures and a balance between the depth of sedation and risk for those who are unable to fast because of the urgent nature of the procedure, a focused airway examination for large (kissing) tonsils or anatomic airway abnormalities that might increase the potential for airway obstruction, a clear understanding of the medication's pharmacokinetic and pharmacodynamic effects and drug interactions, appropriate training and skills in airway management to allow rescue of the patient, age- and size-appropriate equipment for airway management and venous access, appropriate medications and reversal agents, sufficient numbers of appropriately trained staff to both carry out the procedure and monitor the patient, appropriate physiologic monitoring during and after the procedure, a properly equipped and staffed recovery area, recovery to the presedation level of consciousness before discharge from medical/dental supervision, and appropriate discharge instructions. This report was developed through a collaborative effort of the American Academy of Pediatrics and the American Academy of Pediatric Dentistry to offer pediatric providers updated information and guidance in delivering safe sedation to children.

The effect of nitrous oxide in comparison to oxygen combined with fentanyl on the hospitalization time and pain reduction in renal colic patients at emergency department

Background

Renal colic is a painful medical emergency, needs urgent intervention to reduce pain. Nonsteroidal anti-inflammatory drugs, opioids, and entonox are pain-relieving agents. This study was aimed to compare fentanyl + entonox (nitrous oxide + O₂) versus fentanyl + oxygen.

Materials and Methods

One hundred and twenty patients with acute renal colic presenting to the emergency department were enrolled. First, 50 μg fentanyl was infused for all patients. Then, patients divided into two groups receiving masks of entonox and oxygen, respectively. Quantitative measurement of pain was performed by visual analog scale, before the intervention, after 3, 5, 10, and 30 min of that. If the pain was not relieved after 30 min, 50 μg fentanyl was infused. If the pain was still continued, ketorolac and ketamine were used. Hospitalization duration and severity of pain at specified times were compared between patients in two groups.

Results

The mean (standard deviation) time of hospitalization was 211 (59) and 236 (61) min in fentanyl + entonox and fentanyl + O₂ groups, respectively (P = 0.024). The decrease in pain severity after 10 and 30 min in fentanyl + entonox group were significantly greater than fentanyl + O₂ group (P = 0.002 and 0.001, respectively). Mean (standard error) of needed time for renal colic pain to get better was 11.27 (1.23) and 20.47 (1.71) min in fentanyl + entonox and fentanyl + O₂ groups, respectively (P < 0.001). Proportion of patients relief from pain in fentanyl + entonox in the second, third, and fourth measurements were significantly more than fentanyl + O₂ group (P = 0.036, P < 0.001, and P < 0.001, respectively).

Conclusion

Entonox is more effective to decrease the duration of hospitalization and reduction of pain than O₂ in renal colic patients.

Colonoscopy quality with Entonox®vs intravenous conscious sedation: 18608 colonoscopy retrospective study

AIM

To compare colonoscopy quality with nitrous oxide gas (Entonox®) against intravenous conscious sedation using midazolam plus opioid.

METHODS

A retrospective analysis was performed on a prospectively held database of 18608 colonoscopies carried out in Lothian health board hospitals between July 2013 and January 2016. The quality of colonoscopies performed with Entonox was compared to intravenous conscious sedation (abbreviated in this article as IVM). Furthermore, the quality of colonoscopies performed with an unmedicated group was compared to IVM. The study used the following key markers of colonoscopy quality: (1) patient comfort scores; (2) caecal intubation rates (CIRs); and (3) polyp detection rates (PDRs). We used binary logistic regression to model the data.

RESULTS

There was no difference in the rate of moderate-to-extreme discomfort between the Entonox and IVM groups (17.9% vs 18.8%; OR = 1.06, 95%CI: 0.95-1.18, P = 0.27). Patients in the unmedicated group were less likely to experience moderate-to-extreme discomfort than those in the IVM group (11.4% vs 18.8%; OR = 0.71, 95%CI: 0.60-0.83, P < 0.001). There was no difference in caecal intubation between the Entonox and IVM groups (94.4% vs 93.7%; OR = 1.08, 95%CI: 0.92-1.28, P = 0.34). There was no difference in caecal intubation between the unmedicated and IVM groups (94.2% vs 93.7%; OR = 0.98, 95%CI: 0.79-1.22, P = 0.87). Polyp detection in the Entonox group was not different from IVM group (35.0% vs 33.1%; OR = 1.01, 95%CI: 0.93-1.10, P = 0.79). Polyp detection in the unmedicated group was not significantly different from the IVM group (37.4% vs 33.1%; OR = 0.97, 95%CI: 0.87-1.08, P = 0.60).

CONCLUSION

The use of Entonox was not associated with lower colonoscopy quality when compared to intravenous conscious sedation using midazolam plus opioid.

[Suturing a child's wound, humanising care in the emergency department]

The humanisation of the care pathway constitutes an objective for all caregivers. A visit to the emergency department by a child requiring a suture is a simple and frequent situation which highlights the different stages of the care. Several of these stages can be anticipated in the waiting room, in particular the exchanging of information with the patient and the family, which helps to improve the parent-child-professional relationship.

Intranasal fentanyl and inhaled nitrous oxide for fracture reduction: The FAN observational study

INTRODUCTION

Procedural sedation and analgesia (PSA) are frequently used for fracture reduction in pediatric emergency departments (ED). Combining intranasal (IN) fentanyl with inhalation of nitrous oxide (N₂O) allow for short recovery time and obviates painful and time-consuming IV access insertions.

METHODS

We performed a bicentric, prospective, observational cohort study. Patients aged 4-18years were included if they received combined PSA with IN fentanyl and N₂O for the reduction of mildly/moderately displaced fracture or of dislocation. Facial Pain Scale Revised (FPS-R) and Face, Leg, Activity, Cry, Consolability (FLACC) scores were used to evaluate pain and anxiety before, during and after procedure. University of Michigan Sedation Score (UMSS), adverse events, detailed side effects and satisfaction of patients, parents and medical staff were recorded at discharge. A follow up telephone call was made after 24-72h.

RESULTS

90 patients were included. There was no difference in FPS-R during the procedure (median score 2 versus 2), but the FLACC score was significantly higher as compared to before (median score 4 versus 0, Δ 2, 95% CI 0, 2). Median UMSS was 1 (95% CI 1, 2). We recorded no serious adverse events. Rate of vomiting was 12% (11/84). Satisfaction was high among participants responding to this question 85/88 (97%) of parents, 74/83 (89%) of patients and 82/85 (96%) of physicians would want the same sedation again.

CONCLUSION

PSA with IN fentanyl and N₂O is effective and safe for the reduction of mildly/moderately displaced fracture or dislocation, and has a high satisfaction rate.

A randomized controlled trial of nitrous oxide for intrauterine device insertion in nulliparous women

OBJECTIVE

To evaluate the effectiveness of inhaled nitrous oxide for pain management among nulliparous women undergoing intrauterine device (IUD) insertion.

METHODS

A double-blind, randomized controlled trial was conducted among nulliparous women aged 13-45years who underwent IUD insertion at a US center between October 1, 2013, and August 31, 2014. Using a computer-generated randomization sequence, participants were randomly assigned to inhale either oxygen (O₂) or a mixture of 50% nitrous oxide and 50% oxygen (N₂O/O₂) through a nasal mask for 2minutes before insertion. Only the person administering the inhalation agent was aware of group assignment. The primary outcome was maximum pain assessed 2minutes after insertion via a 100-mm visual analog scale. Analyses were by intention to treat.

RESULTS

Forty women were assigned to each group. Mean maximum pain score at the time of insertion was 54.3±24.8mm for the N₂O/O₂ group and 55.3±20.9mm for the O₂ group (P=0.86). Adverse effects were reported for 6 (15%) women in the N₂O/O₂ group and 7 (18%) in the O₂ group (P=0.32).

CONCLUSION

N₂O/O₂ did not reduce the pain of IUD insertion among nulliparous women. ClinicalTrials.gov: NCT02391714.

Guidelines for Monitoring and Management of Pediatric Patients Before, During, and After Sedation for Diagnostic and Therapeutic Procedures: Update 2016

The safe sedation of children for procedures requires a systematic approach that includes the following: no administration of sedating medication without the safety net of medical/dental supervision, careful presedation evaluation for underlying medical or surgical conditions that would place the child at increased risk from sedating medications, appropriate fasting for elective procedures and a balance between the depth of sedation and risk for those who are unable to fast because of the urgent nature of the procedure, a focused airway examination for large (kissing) tonsils or anatomic airway abnormalities that might increase the potential for airway obstruction, a clear understanding of the medication's pharmacokinetic and pharmacodynamic effects and drug interactions, appropriate training and skills in airway management to allow rescue of the patient, age- and size-appropriate equipment for airway management and venous access, appropriate medications and reversal agents, sufficient numbers of staff to both carry out the procedure and monitor the patient, appropriate physiologic monitoring during and after the procedure, a properly equipped and staffed recovery area, recovery to the presedation level of consciousness before discharge from medical/dental supervision, and appropriate discharge instructions. This report was developed through a collaborative effort of the American Academy of Pediatrics and the American Academy of Pediatric Dentistry to offer pediatric providers updated information and guidance in delivering safe sedation to children.

Nitrous oxide speeds the reduction of distressing intrusive memories in an experimental model of psychological trauma

BACKGROUND

Post-traumatic stress disorder (PTSD) involves maladaptive long-term memory formation which underlies involuntary intrusive thoughts about the trauma. Preventing the development of such maladaptive memory is a key aim in preventing the development of PTSD. We examined whether the N-methyl d-aspartate receptor (NMDAR) antagonist gas nitrous oxide (N2O) could reduce the frequency of intrusive memories by inhibiting NMDAR-dependent memory consolidation in a laboratory analogue of psychological trauma.

METHOD

Participants were randomized to inhale N2O (N = 25) or medical air (N = 25) after viewing a negatively valenced emotional film clip ('trauma film'). Participants subsequently completed a daily diary assessing frequency of intrusive thoughts relating to the film clip. A week later, participants completed an explicit memory recall task related to the film.

RESULTS

Post-encoding N2O sped the reduction in intrusive memory frequency, with a significant reduction by the next day in the N2O group compared to 4 days later in the air group. N2O also interacted with post-film dissociation, producing increased intrusion frequency in those who were highly dissociated at baseline. Sleep length and quality the night after viewing the film did not differ between the groups.

CONCLUSION

N2O speeds the reduction of intrusive analogue trauma memory in a time-dependent manner, consistent with sleep-dependent long-term consolidation disruption. Further research with this drug is warranted to determine its potential to inoculate against enduring effects of psychological trauma; however, caution is also urged in dissociated individuals where N2O may aggravate PTSD-like symptomatology.

Analgesic Effects of Inhalation of Nitric Oxide (Entonox) and Parenteral Morphine Sulfate in Patients with Renal Colic; A Randomized Clinical Trial

OBJECTIVE

To compare the analgesiceffects of Nitrous oxide and morphine sulfate in patients with acute renal colic due to urolithiasis.

METHODS

This was randomized clinical trial being performed in Imam Hossein hospital affiliated with Shahid Beheshti University of Medical Sciences during a 1-year period from May2013 to May2014.  A total of number of 100 patients, with an age range of 20-50 years, who presented with renal colic secondary to urolithiasis confirmed by ultrasonography were randomly assigned to receive morphine sulfate injection (0.1 mg/kg) with 100 mg diclofenac suppository (n=50) or Entonox exhalation (50% nitric oxide and 50% oxygen) for 30-minutes with 100 mg diclofenac suppository (n=50). Quantitative measurement was of pain was performed according to a visual analogue scale (VAS), before, 3, 5, 10 and 30-minute after the intervention. The pain severity and side effects were measured between two study groups.

RESULTS

The baseline characteristics of the patients in two study groups were comparable. The frequencies of pain persistence (at least 50%) at 3-, 5-, 10- and 30-minute intervals in morphine sulfategroup were 96%, 80%, 50% and 8%, respectively; these frequencies in Entonex  were 82%, 42%, 12% and 2%, respectively (p<0.001). Cox regression modeling showed that use of Entonox was the only effective agent in the success of treatment, compared to the use of morphine, i.e. use of Entonox increased the success of treatment up to 2.1 folds compared to the use of morphine (HR=2.1; 95% CI: 1.2-3.6; p=0.006).

CONCLUSION

The results of the present study demonstrate that inhalation of Entonox is an effective and safe analgesic regimen for acute renal colic. It acts more rapidly and is more potent in relieving renal colic when compared to morphine sulfate.Entonox can be regarded as an appropriate alternative to analgesics like opioids in this ground.

Reduction of anterior shoulder dislocation in emergency department; is entonox(®) effective?

INTRODUCTION

An appropriate procedural sedation and analgesia (PSA) is crucial to reduce a dislocated shoulder successfully in emergency department. This study compares sedative effect of inhalational Entonox(®) (En) to intra-venous (IV) Midazolam plus Fentanyl (F+M).

METHODS

120 patients with recurrent anterior shoulder dislocation were randomly assigned into two groups. 60 patients (group F+M) received 0.1 mg/kg IV Midazolam plus 3µg/kg IV Fentanyl and 60 patients (group En) received Entonox(®) with self administration face mask on an on-demand basis. Traction/counter-traction method was used to reduce the dislocated shoulder joint in both groups.

RESULTS

48 out of 60 (80%) patients in group F+M and 6 out of 60 (10%) patients in group En had successful reduction (p < 0.0001). The mean pain score reduction was 6.3 ± 1.2 for group F+M and 3 ± 0.9 for group En (p < 0.0001). There was a statistically significant difference in mean patient satisfaction (assessed with Likert score) between two groups (4.45 ± 0.6 for group F+M and 2.3 ± 1 for group En; p < 0.0001). Duration of entire procedure (since the beginning of PSA up to the end of successful or unsuccessful reduction) was shorter in Group F+M, but successful reductions occurred earlier in group En. No major side effect such as airway compromise, retracted respiratory depression, or circulatory failure was occurred in any group.

CONCLUSION

Entonox(®) may not be an appropriate agent to help reducing a dislocated shoulder.

Nitrous oxide for colonoscopy

BACKGROUND

Colonoscopy is the gold standard investigation for large bowel disease. With the increase in demand, pressure is on clinics to shorten lengths of time per procedure in addition to maintaining high levels of patient safety. Analgesia has always been the mainstay of adequate pain relief, but it leads to prolonged recovery and lengths of hospital stay, in addition to increased risk of cardio-respiratory side effects. N2O/O2 mixtures have been used for its effective analgesic effect and short half life and provides an alternative method of sedation for colonoscopy procedures.

OBJECTIVES

The primary objective was to compare the overall effectiveness of nitrous oxide mixtures to other types of pain relief used during colonoscopy procedures to provide adequate pain/discomfort relief.The secondary objective was to compare between nitrous oxide and other types of pain relief with respect to hospitalisation/recovery time, side effects, patients and endoscopists satisfaction, and colonoscopy completion rates.

SEARCH STRATEGY

The following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library, MEDLINE (1966- present), EMBASE (1980 - present), and the Internet (Google Scholar).

SELECTION CRITERIA

Randomised controlled trials which compared nitrous oxide to placebo or active comparators for patients undergoing elective colonoscopic procedures. Patients with known underlying causes of pain/discomfort were excluded. 

DATA COLLECTION AND ANALYSIS

Seven randomised trials were included. Each trial compared a nitrous oxide/oxygen mixture to a placebo or sedation +- other analgesic drugs on patients undergoing elective colonoscopic procedures. The results of these studies were analysed and discussed.

MAIN RESULTS

There were a total of 547 patients included.There were 257 patients randomised to receive the N2O/O2 mixture (7 studies), while 225 patients received some form of sedation with or without other analgesia (6 studies), and 65 patients received a placebo (3 studies).Four studies showed that N2O/O2 is as good in controlling pain/discomfort as conventional methods, while one showed sedation was better and another study showed N2O/O2 was better.Six of the studies showed that N2O/O2 groups had quicker recovery times and shorter lengths of hospital stays while one study showed that there was no difference between the two groups.Two studies showed that N2O/O2 was safer while one reported that sedation was safer.

AUTHORS' CONCLUSIONS

Nitrous oxide is as efficient and safer than various pain relief methods used during colonoscopy procedures, but further trials are necessary.

Nitrous oxide for colonoscopy

BACKGROUND

Colonoscopy is the gold standard investigation for large bowel disease. With the increase in demand, pressure is on clinics to shorten lengths of time per procedure in addition to maintaining high levels of patient safety. Analgesia has always been the mainstay of adequate pain relief, but it leads to prolonged recovery and lengths of hospital stay, in addition to increased risk of cardio-respiratory side effects. N2O/O2 mixtures have been used for its effective analgesic effect and short half life and provides an alternative method of sedation for colonoscopy procedures.

OBJECTIVES

The primary objective was to compare the overall effectiveness of nitrous oxide mixtures to other types of pain relief used during colonoscopy procedures to provide adequate pain/discomfort relief.The secondary objective was to compare between nitrous oxide and other types of pain relief with respect to hospitalisation/recovery time, side effects, patients and endoscopists satisfaction, and colonoscopy completion rates.

SEARCH STRATEGY

The following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library, MEDLINE (1966- present), EMBASE (1980 - present), and the Internet (Google Scholar).

SELECTION CRITERIA

Randomised controlled trials which compared nitrous oxide to placebo or active comparators for patients undergoing elective colonoscopic procedures. Patients with known underlying causes of pain/discomfort were excluded. 

DATA COLLECTION AND ANALYSIS

Seven randomised trials were included. Each trial compared a nitrous oxide/oxygen mixture to a placebo or sedation +- other analgesic drugs on patients undergoing elective colonoscopic procedures. The results of these studies were analysed and discussed.

MAIN RESULTS

There were a total of 547 patients included.There were 257 patients randomised to receive the N2O/O2 mixture (7 studies), while 225 patients received some form of sedation with or without other analgesia (6 studies), and 65 patients received a placebo (3 studies).Four studies showed that N2O/O2 is as good in controlling pain/discomfort as conventional methods, while one showed sedation was better and another study showed N2O/O2 was better.Six of the studies showed that N2O/O2 groups had quicker recovery times and shorter lengths of hospital stays while one study showed that there was no difference between the two groups.Two studies showed that N2O/O2 was safer while one reported that sedation was safer.

AUTHORS' CONCLUSIONS

Nitrous oxide is as efficient and safer than various pain relief methods used during colonoscopy procedures, but further trials are necessary.

[Safety and effectiveness of nitrous oxide for sedation-analgesia in emergency departments]

OBJECTIVES

PRIMARY OBJECTIVES

to assess the safety and the effectiveness (analysing the behaviour of the patient) with the use of nitrous oxide during the performance of painful procedures in the Paediatric Emergency Departments (PED); secondary objectives: to evaluate the manageability of the method and its acceptance by both the medical team and the patient.

PATIENTS AND METHODS

Post-marketing observational, prospective, multicentre, non-randomised and open (November 2007-December 2008) study, which involved seven national PED. We included patients between 2 and 18 years-old on whom a painful procedure was performed in the PED and nitrous oxide was used.

RESULTS

A total 213 patients were included (27,2% < 5 years). Patient behaviour was considered «good/very good» in 79,7%, with no statistically significant difference in relation to the procedure performed. Patient behaviour was more often classified as «bad/accept with difficulty» among those < 5 years (33.3% vs 15.1%, P=.006). Adverse events occurred in 17 cases (7.9%), with no significant difference in the rate in relation to the age, fasting or not or in association with other drugs; the most frequent were dizziness and/or headache (10), followed by vomiting (3). The administration was considered easy by the medical team in the 96.6% of the cases. Parents would accept the use of nitrous oxide in their child in a similar situation in 92.7% of the cases.

CONCLUSIONS

Administration of nitrous oxide achieves proper sedation and analgesia during painful procedures, especially in children older than 5 years. Adverse events reported were few, mild and expected. Most parents would accept its use again in a similar situation.

Guidelines for monitoring and management of pediatric patients during and after sedation for diagnostic and therapeutic procedures: an update

The safe sedation of children for procedures requires a systematic approach that includes the following: no administration of sedating medication without the safety net of medical supervision; careful presedation evaluation for underlying medical or surgical conditions that would place the child at increased risk from sedating medications; appropriate fasting for elective procedures and a balance between depth of sedation and risk for those who are unable to fast because of the urgent nature of the procedure; a focused airway examination for large tonsils or anatomic airway abnormalities that might increase the potential for airway obstruction; a clear understanding of the pharmacokinetic and pharmacodynamic effects of the medications used for sedation, as well as an appreciation for drug interactions; appropriate training and skills in airway management to allow rescue of the patient; age- and size-appropriate equipment for airway management and venous access; appropriate medications and reversal agents; sufficient numbers of people to carry out the procedure and monitor the patient; appropriate physiologic monitoring during and after the procedure; a properly equipped and staffed recovery area; recovery to presedation level of consciousness before discharge from medical supervision; and appropriate discharge instructions. This report was developed through a collaborative effort of the American Academy of Pediatrics and the American Academy of Pediatric Dentistry to offer pediatric providers updated information and guidance in delivering safe sedation to children.

Prehospital management of lower limb fractures

Lower limb fractures are common injuries in prehospital care. Untreated fractures can lead to hypovolaemic shock especially if open, and should be treated with effective haemorrhage control and splintage. A brief assessment for open fractures, deformity, and neurovascular compromise should be followed by effective analgesia, wound management, reduction (if needed), splintage, and packaging of the patient. Early appropriate management reduces the morbidity and mortality of lower limb fractures.

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

The concept of premixed 50% nitrous oxide and oxygen dated back to 1961 in England, where it is commercialised under the name Entonox. In France, after a so marginal use, premixed 50% nitrous oxide and oxygen now knows such a revival since we first consider the pain provoked by the cure. To use correctly premixed 50% nitrous oxide and oxygen, we need to know the main properties of the nitrous oxide. The four commercial versions, now on the market, are presented (Kalinox, Medimix, Antasol, Oxynox. Except a few contraindications, these indications are large, as well at hospital as outside. In less than 10% of the cases, side effects are possible. Conditions of administration are given in details. The limits of the technic and the particular precautions of use are precised.

Pain management and regional anaesthesia in the trauma patient

PURPOSE OF THE REVIEW

Treatment of the trauma patient has evolved rapidly in the past decade. Nevertheless, the treatment of pain as part of overall trauma management has been relatively neglected. This update reviews recent publications related to pain relief in the trauma patient.

RECENT FINDINGS

Although recent publications suggest that the assessment and treatment of pain in trauma have improved, most studies still document inadequate analgesia. We discuss the use of different analgesia strategies in the prehospital and emergency room settings.

SUMMARY

Educating the emergency room staff to perform early routine assessment of pain and to be familiar with the administration of analgesia are key elements to improved pain management in trauma. Peripheral nerve block techniques should be practised by emergency room staff. If simple techniques are chosen, competence can be achieved with short, focused training sessions. Further developments are needed in order to provide safer and more effective analgesia to the trauma patient.

Nitrous oxide in emergency medicine

Safe and predictable analgesia is required for the potentially painful or uncomfortable procedures often undertaken in an emergency department. The characteristics of an ideal analgesic agent are safety, predictability, non-invasive delivery, freedom from side effects, simplicity of use, and a rapid onset and offset. Newer approaches have threatened the widespread use of nitrous oxide, but despite its long history this simple gas still has much to offer. "I am sure the air in heaven must be this wonder-working gas of delight". Robert Southey, Poet (1774 to 1843)