Dear Editor

I read kennedy et al's article regarding the use of topical cocaine and adrenaline with interest.

I have also seen instillagel (2% lignocaine and 0.25% chlorhexidine)used with good effect when placed on childrens wounds to allow exploration and closure within the emergency department setting.

The great advantages being that it is easily available within the department and when working out safe doses lignocaine is a familiar drug and is also the drug of choice if supplemental injections are needed. If these injections are placed through the cut edge where the gel has been applied the distress to the child is minimal.

Dear Editor

For feeble-minded souls such as myself, the aide mémoire has played a key part in my professional life. Some 30 years ago whilst demonstrating anatomy at Cambridge, I devised numerous mnemonics to assist with teaching. To illustrate their power, whilst I have forgotten the names of virtually all my students and most of my fellow demonstrators, I can recall each and every segment of the right lung, all the branches of the internal carotid artery and many other obscure anatomical facts without the slightest difficulty, despite their total irrelevance to my current clinical practice. It was with great interest, therefore, that I read the article by Dyson et al [1]. describing their aide mémoire for electromechanical dissociation, and I welcome it as a significant improvement on the traditional ‘4Hs & 4Ts’ method of recalling potentially reversible causes of pulseless electrical activity.

I was intrigued, however, to observe that the authors had chosen to work with the term ‘electro-mechanical dissociation’ (EMD) rather than ‘pulseless electrical activity’ (PEA) which has become the more commonly used phrase in recent years. I suspect that this may have had something to do with the fact that they were able make the EMD acronym appear in the second of the two triangles (representing Electrolyte + metabolic, Massive hypothermia and Drugs + toxins) as a reminder of the final three causes of EMD. If so, I’m not sure that the word ‘massive’ really works in front of ‘hypothermia’ since it is not an adjective normally associated with this condition, being more commonly applied to describe a heart attack, stroke or pulmonary embolus. For me, use of the word ‘massive’ in this context seems just a bit too contrived.

After wrestling with the conundrum, I can reveal that the authors could indeed have utilised the more widely accepted PEA acronym, and still have had it appear in the second of the two triangles. This can be done by defining the final three causes of PEA as: Pharmacological + toxic, Electolytic + metabolic, and Algidity. For those unfamiliar with the word algidity, the dictionary definition is chilliness or coldness, and especially (in the medical sense) ‘coldness with collapse’ [2]. An additional advantage of using the PEA rather than the EMD acronym would be that the initial letter of PEA would remind readers that there are 3Ps (Pneumothorax (tension), Pulmonary embolus and Pericardial tamponade) in the first of the two triangles.

So it has to be two-and-a-half cheers for Dyson et al. and more aide mémoires please!

References

(1) Educational psychology in medical learning: a randomised controlled trial of two aide memoires for the recall of causes of electromechanical dissociation. Dyson E, Voisey S, Hughes S, Higgins B, McQuillan PJ. Emerg Med J 2004;21:457-460.

(2) See: http://cancerweb.ncl.ac.uk/cgi-bin/omd?algidity published by Dept. of Medical Oncology, University of Newcastle upon Tyne.

Dear Editor

I read with some surprise Dr Leaman's article on the impact of the NICE guidelines on a district general hospital.[1] I am truly confused at the level of anxiety this topic is causing in the UK. In most other developed countries, the use of skull x-rays have long been abandoned in favour of selected use of CT scans in patients with head injuries.

While I appreciate the increased resource implications inherent in the extablishment of these guidelines, I really do not see that there is a viable alternative, apart from reliance on an outdated mode of investigation (skull x-ray) in what should be a first world setting.

In our paediatric department, we started relying on a modified version of the American Academy of Pediatrics guidelines since 2001. The use of skull x-rays have dramatically fallen, while there has only been a modest rise in the use of CT scans for minor head injured patients.

I do agree with the Dr Leaman's point regarding out of hours scans, but we really have no firm evidence on which to base our assumption that patients requiring a scan can always wait until the morninig. On the other hand, implementation of the NICE guidelines, along with careful audit will provide us with such data, at which time we can safely modify the guidelines to suit local practice.

It is time that the UK falls into line with modern practice regarding the management of head injuries, even if this means an increase in resource use.

Reference

1. A M Leaman. The NICE guidelines for the management of head injury: the view from a district hospital. Emerg Med J 2004; 21: 400.

Dear Editor

I was interested to read the letter by Pattinson et al [1] reviewing the use of the single-use laryngeal mask airway (LMA-Unique) over a two- year period in the ambulance service in Warwickshire. In their summary, the authors commented that their success rates for LMA insertion were similar to those reported in the literature and that the introduction of LMAs, ‘had achieved the aims that were intended’.

I was disappointed to find that there was no mention of patient outcomes in this review, and I would have liked to have known if use of the LMA had influenced the rates at which patients were admitted alive to hospital and subsequently discharged home alive. Also, in those cases where the LMA was used for conditions other than cardiac arrest, details of SpO2 readings pre- and post-insertion would have provided useful information regarding the efficacy of the LMA in prehospital care. I would suggest that the introduction of any new device into emergency medicine can only be judged to be a success if its use can be shown to have improved the clinical outcome for patients, and the ability of staff to utilise the device is not the same thing.

From the figures quoted, it would appear that there may have been some reluctance by paramedics in Warwickshire to utilise the LMA, since there were only 45 attempted LMA placements by paramedics during the entire two years under study, and it would have been interesting to know the number of tracheal intubations attempted over the same period. The higher rate of successful LMA insertions by Warwickshire technicians as opposed to paramedics (96% v. 82%) could simply reflect differences in the complexity of cases treated, and a direct comparison of successful insertion rates in cardiac arrest cases where there was unimpeded access to the patient would have been interesting. The relatively small number of LMA placements in this survey probably makes it impossible to come to any firm conclusion as to whether use of the LMA is more efficacious than bag- valve-mask ventilation (BVMV) or tracheal intubation (TI) in frontline ambulance care, and what is urgently needed from the ambulance service is a well-designed prospective study to address all these issues.

One final comment; the authors state that the LMA is ‘clearly unrivalled in situations where intubation has failed or is impossible’. This is certainly not the case, since the esophageal tracheal Combitube (ETC), for example, is another effective rescue ventilation device [2]. The ETC may, in fact, be a better rescue ventilation tool in cases where there is reduced lung/chest wall compliance or where airway resistance is high (e.g. severe bronchospasm), since the cuff of the standard LMA only provides a reliable seal up to about 20 cmH2O of airway pressure. Currently, the LMA and the ETC are the only two rescue ventilation devices with an American Heart Association (AHA) Class IIa designation (ASA Class IIa status is reserved for a therapeutic option for which the weight of evidence is in favour of its usefulness and efficacy). However, other rescue ventilation devices such as the King LTA, LMA-ProSeal and LMA- Fastrach also show promise and deserve further study.

Unlike in the United States, the ETC has been used very little in prehospital emergency care in the UK. In a recent postal survey [3], whilst the availability of the LMA had increased from 10 to 26% since the previous survey in 1997, no ambulance service in the UK was employing the ETC, or any other alternate airway device. Fortunately, true ‘cannot intubate, cannot ventilate’ situations are relatively rare. Nevertheless, with only 26% of UK frontline ambulances carrying any type of rescue ventilation device, it has to be questioned whether hypoxic patients who are resistant TI and are unresponsive to BVMV are currently being offered an acceptable standard of care in this country.

CONFLICT OF INTEREST STATEMENT: Dr Mason is Adviser in Pre-Hospital Care to Intavent Orthofix, Maidenhead, UK - distributor of the LMA in the UK.

References

(1) Pattinson K, Todd I Thomas J, Wyse M. A two year review of laryngeal mask use by the Warwickshire ambulance service. Emerg Med J 2004;21:397.

(2) Rich JM, Mason AM, Bey TA, Krafft P, Frass M. The critical airway, rescue ventilation and the Combitube: Part 1. AANA J 2004;72(1):17 -27.

(3) Roberts K, Allison KP, Porter KM. A review of emergency equipment carried and procedures performed by UK front line paramedics. Resuscitation 2003;58(2):153-8.