Procedural sedation and analgesia for adults in the emergency departmentBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g2965 (Published 08 May 2014) Cite this as: BMJ 2014;348:g2965
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As a current trainee in the Emergency Department, I found this article on procedural sedation of excellent value . During my training I have found the use of appropriate procedural sedation and analgesia in paediatric cases to be one lacking in clear guidance, and would like to take this opportunity to expand on some of the evidence currently available.
As your article has outlined, effective sedation and analgesia is an important facet of emergency medicine, acting to reduce patient distress, decrease recovery times, and decrease failure rates of procedures. Appropriate administration in patients also acts to reduce adverse psychological response to pain encountered in the future .
The use of inhaled Nitrous Oxide (N2O/O2) is used widely in Emergency Departments, harnessing its opioid agonist and NMDA glutamate antagonist actions to produce mild-moderate linear dose dependent anxiolytic, analgesia and amnesic properties . It offers comparative cardio-respiratory stability though may enhance the cardio-respiratory depressive effects of other agents when administered together .
The American College of Emergency Physicians makes the recommendation that 50% nitrous oxide used with local anaesthetic provides safe and effective procedural sedation. In children, continuous valve circuits for inhaled nitrous oxide delivery have been demonstrated to be more appropriate and easy to activate than the demand valve equipped fixed 50% devices used commonly for adults.
Numerous papers have shown reduced levels of distress in children receiving N2O/O2 for painful procedures including lumbar punctures, abscess drainage, cyst excision and fracture reduction . Luhmann et al.  demonstrated reduced pain and distress with 50% N2O/O2 compared with oral midazolam administration for wound cleaning, lidocaine administration and suturing in children aged 2-6 years. However, although better than placebo, the general consensus is that the effects of nitrous oxide administration appear to be somewhat less effective for those under the age of 6-8 years, with comparatively more distress during painful procedures noted with decreasing age .
Hennrikus et al.  demonstrated that the combination of inhaled nitrous oxide with a haematoma block, rather than the use of nitrous oxide alone, was more effective at reducing distress during the reduction of fractures in children. Haematoma blocks have not been shown to reduce fracture healing  and can be effective even in completely displaced and overriding fractures.
Luhmann et al.  add support to this when they looked at the use of 50% N2O/O2 combined with a lidocaine hematoma block, compared to the administration of IV ketamine at (1mg/kg) combined with midazolam (0.1mg/kg max 2mg) for the reduction of forearm fracture reduction in 102 children aged between 5-17 years. All participants received oxycodone 45 mins prior to the procedure. Using a procedural behavioural checklist score (PBCL) to measure levels of distress in children, this study demonstrated that although both ketamine/midazolam and N2O/O2 / haematoma block combinations had low PBCL scores in keeping with low levels of distress during the procedure, less distress and less memory of pain was experienced with N2O/O2 / haematoma block combination. This combination was also associated with a faster recovery time of 16 mins on average compared with 83 mins for the ketamine/midazolam combination, an understandably important consideration in busy Accident and Emergency departments which rely on an efficient flow of patients to function optimally. In addition, it was observed that both combinations resulted in some adverse effects e.g. vomiting, ataxia, but these were greater for the ketamine/midazolam combination both immediately after the procedure and at 1 day post procedure follow up.
The most commonly observed side effect of nitrous oxide administration in literature is that of emesis, found to be more common in children than in adults , and enhanced when co-administered with opiates. This effect is thought to be a result of increased catecholamine release increasing sympathetic stimulation, enhanced vestibular stimulation resulting in middle ear pressure chances and increased gastrointestinal distension . Although co-administration with opiates may depress laryngeal reflexes these protective reflexes are shown to be present with inhaled nitrous oxide alone .
In conclusion, evidence available is strongly in favour of the use of nitrous oxide coupled with local anaesthetic for many Emergency Department procedures. The use of nitrous oxide and local anaesthetic has shown to reduce distress during painful procedures and has a quick onset and recovery, making it very suitable for use in the emergency department under the supervision of appropriately trained ED staff.
 Atkinson et al., Procedural sedation and analgesia for adults in the emergency department, BMJ 2014; 348 doi: http://dx.doi.org/10.1136/bmj.g2965 (Published 08 May 2014)
 Mace, S et al., American College of Emergency Physicians, Clinical Policy: Critical Issues in the Sedation of Paediatric Patients in the Emergency Department, available at: https://www3.acep.org/assets/0/16/898/900/76F03F4C-B2F4-451D-BE08-911793.... Last accessed Jan 2015.
 Luhmann JD, Kennedy RM, Porter FL, et al. A randomized clinical trial of continuous-flow nitrous oxide and midazolam for sedation of young children during laceration repair. Ann Emerg Med. 2001;37:20-27.
 Hennrikus WL, Shin AY, Klingelberger CE. Self-administered nitrous oxide and a hematoma block for analgesia in the outpatient reduction of fractures in children. J Bone Joint Surg Am. 1995;77-A:335–339
 Henry B, Kenison M, McVay C, et al. The effect of local hematoma blocks on early fracture healing. Orthopedics. 2002;25; 469–470
 Luhmann JD, Schootman M, Luhmann SJ, et al. A randomized comparison of nitrous oxide plus hematoma block versus ketamine plus midazolam for emergency department forearm fracture reduction in children. Pediatrics. 2006;118:e1078-e1086.
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Competing interests: No competing interests
We read with interest the recent article by Atkinson et al but would question the advice given1. A patient requiring relocation of a dislocated shoulder which has failed using “minimal sedation and analgesia” 2 with intravenous fentanyl now requires moderate sedation for the procedure to be re attempted.
Atkinson and colleagues recommend that propofol would be an acceptable and safe agent to use in the emergency department for this procedure. We would disagree with this. Firstly, as they have described in their article, sedation is a continuum and “deep” sedation may easily and quickly lapse into general anaesthesia, sometimes in an unpredictable manner. The therapeutic range of propofol to maintain “light to moderate” sedation is narrow 3. This would be even more important to consider in this case as the patient has received intravenous fentanyl already and so the synergistic effect of the opiate with propofol could be unexpected. These patient safety concerns are the basis upon which 21 national societies of anaesthesiology in Europe have signed a consensus agreement that propofol should only be administered by those trained in the administration of general anaesthesia.
Atkinson et al 1 advise that similar levels of governance are used to manage sedation as with general anaesthesia. We would expect this to include fasting times, which as recommended by the ASA taskforce 4 would be a minimum of 6 hours for solid food (light meal) and 2 hours for clear fluids. This guideline clearly states that it applies both to general anaesthesia, regional anaesthesia and sedation/analgesia (i.e., monitored anaesthesia care). We believe the patient in the article falls under this guideline. This guideline is also recommended by the AAGBI 5, by which all UK hospitals and anaesthetists practice. The patient in this case had only been fasted for 4 hours, during which time she had sustained a painful injury and received intravenous opiates. We would not deem her to have an empty stomach due to the inadequate fasting time. Pain and subsequent opiate administration are known to reduce bowel motility and delay stomach emptying further. We would expect all clinicians trained in the administration of general anaesthesia to identify that this patient was not adequately fasted to undergo sedation or general anaesthesia. For this reason we would be concerned that the clinicians involved in this case had not received adequate training and may have perpetuated the error with their own trainees.
1. Atkinson, P., French, J. and Nice, CA. Procedural sedation and analgesia for adults in the emergency department. BMJ 2014; 348
2. American Society of Anesthesiologists Task Force on Sedation and Analgesia by Non-Anesthesiologists. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002;96:1004-17.
3. Perel, A. Non-anaesthesiologists should not be allowed to administer propofol for procedural sedation: a Consensus Statement of 21 European National Societies of Anaesthesia. Eur J Anaesthesiol 2011;28:580-584
4. American Society of Anesthesiologists Committee on Standards and Practice Parameters. Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures. Anesthesiology 2011: 114: 495-511
5. AAGBI Working Party. AAGBI Safety Guideline Pre-operative Assessment and Patient Preparation The Role of the Anaesthetist. 2010. Appendix 1.
Competing interests: No competing interests
As a group of anaesthetic trainees based in the United Kingdom, we read with interest your recent practice article discussing procedural sedation . It is always refreshing to contrast practices from different regions, and even more so different continents. However, we feel that we should highlight a few small, but serious, omissions that raise patient safety concerns.
What constitutes an appropriate level of sedation to be undertaken in the emergency department without anaesthetic input has always been debated, with moderate and deep levels of sedation lying squarely within this grey area. The use of multiple agents, in particular combining a strong opiate and an anaesthetic agent such as propofol could well be considered a general anaesthetic, carrying considerable risks to the airway, respiratory and cardiovascular systems. Such complications are more likely when doses are not reduced according to their synergistic effect and the physiological status of the patient.
Patient safety is paramount and any sedative procedure should be performed under experienced supervision with appropriate safety considerations , including monitoring , airway and resuscitative equipment and emergency drugs. Whilst this article primarily discusses the pharmacology of sedation we feel these safety aspects should have been given greater credence. Appropriate starvation has been somewhat neglected within the article, as have the risks of aspiration and the effects of trauma or opiates on gastric emptying, although it is appreciated the American College of Emergency Physicians guidance attributes little risk to this .
The authors provide a fair and well-presented summary of many of the pharmacological options available for sedation, but there are some significant and potentially dangerous omissions. In particular it should be noted that all opiates can cause sedation even in modest doses, especially in the elderly and opiate naive populations.
We feel it imperative to highlight that although there is an expanding body of experience with remifentanil sedation this is primarily within anaesthesia, to the extent that the ACEP guidance does not recommend its use in the ED . It is an incredibly potent opiate, not only producing excellent analgesia but also apnoea, even in the awake patient [5,6], stiff chest, profound bradycardia and hypotension. Inexperience with remifentanil is potentially lethal. In anaesthetic practice it is almost exclusively given by continuous infusion via specialist syringe pumps. Volumes given can be incredibly small and the inference from Table 1 that it could be given by manual bolus is, in our opinion, an extremely dangerous practice with a high risk of adverse events.
The concept of ‘ketofol’ we confess to be somewhat ignorant of, although we are aware of its use in certain centres within the UK. We would be interested to learn more about this sedation technique and we ask the authors to clarify their description of a 1:1 mixture since both propofol and ketamine are available in differing strengths, exposing the inexperienced to a significant margin of error.
It has been fascinating to learn about differing practices for procedural sedation and we welcome the opportunity to further discuss the important surrounding issues. Summarising sedation practices in an open and clear way is of great value, but we must advise anyone undertaking procedural sedation to ensure they have the correct competencies, experience, resources and knowledge of the drugs to be used.
 Atkinson P, French J, Nice CA. Procedural sedation and analgesia for adults in the emergency department. BMJ. 2014 May 8;348(may08 3):g2965–g2965
 Cook TM, Woodall N, Frerk C. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. Part 1: Anaesthesia. Br J Anaesth. 2011 May 1;106(5):617–31.
 Recommendations for standards of monitoring during anaesthesia and recovery, 4th ed. Association of Anaesthetics of Great Britain and Ireland, 2007.
 Goodwin SA et al Clinical Policy: Procedural Sedation and Analgesia in the Emergency Department, Ann Emerg Med. 2014;63:247-258.
 Marr R, Hyams J, Bythell V. Cardiac arrest in an obstetric patient using remifentanil patient-controlled analgesia. Anaesthesia. 2013 Mar;68(3):283–7.
 Bonner JC, McClymont W. Respiratory arrest in an obstetric patient using remifentanil patient-controlled analgesia. Anaesthesia. 2012 May;67(5):538–40
Competing interests: No competing interests