Dear Sir,

We read with interest the study by Babl et al “limited analgesia efficacy of nitrous oxide for painful procedures in children” published in the EMJ November 2008 Vol 25 No 11.

Central to the protocol and management is the use of clinical assessment to determine adequacy and depth of analgesia/ sedation. We agree with this wholeheartedly and support this method as it emphasises the importance of conscious sedation as an adjunct to therapy, rather than unconscious sedation to compensate for inadequate analgesia. However it is worth recognising that the inspired concentration (in your study stated as 50-70% N20) does not relate to effector site concentration (in this case the central nervous system) unless a steady state has been achieved, the period of equilibration being approximately ten minutes. Without a closed breathing circuit being used there will inevitably be a significant entrainment of air resulting in a further reduction in real versus expected nitrous oxide concentration. This means that the nitrous oxide concentration achieved in the children in your study will be significantly lower than the settings on the machines would suggest and be unpredictably variable.

In our experience using a closed mask system (such as a T – piece or close fitting demand mask) and end tidal gas monitoring provides a breath by breath analysis of end tidal nitrous oxide and oxygen concentration. These are analogous to arterial blood levels and thus reflect much more closely the effector site concentration.

As a second point we note that all 8 patients who received codeine (which has a sedative effect) within two hours of sedation were not excluded from the study, although it was stated in the protocol that those given sedatives would be excluded.

We agree with your findings that nitrous oxide is a useful adjunct in conscious sedation in painful procedures in children. We suggest this could be made more effective and predictable delivering nitrous oxide within an anaesthetic closed circuit in the Emergency department using end tidal gas monitoring.

Dear Sirs,

We would like to thank the authors for their contribution to the debate concerning the diagnostic use of natriuretic peptides. As a component of an integrated diagnostic scheme1 their further insight into variations in levels is helpful however some clarification is required and that the results should be interpreted with a degree of circumspection. Choi et al have separated their patients into two cohorts, in those without underlying disease a significant and important group with pneumonia and sepsis were included. The reported mean value could be biased by the inclusion of this group as myocardial dysfunction due to sepsis causes raised levels of natriuretic peptides and can be used to differentiate survivors and non-survivors.(1,2) They also have not reported if there were any echocardiographic changes of left ventricular hypertrophy or right ventricular dysfunction, in either cohort, which could be associated with minor or moderate increases in BNP. In the subset of patients with hypertension, diabetes and angina they fail to comment on the presence of left ventricular dysfunction where concentrations of BNP may overlap normal concentrations2. In addition the lack of an admission diagnosis of chronic obstructive pulmonary disease (COPD) is relevant as exacerbations of COPD are frequently missed in the emergency department1. The other issue to be considered is that natriuretic peptide levels may be increased in the population before the onset of detectable and significant cardiovascular disease(3). In view of the potential bias, caution is urged when interpreting these results and applying them to a population. Further investigation and characterisation of BNP levels in the Korean population on a large scale basis would be invaluable and in the interim no alteration in the current diagnostic levels should be enacted until this has been done.

References:

1) Phua, J; Lim, Tow K; Lee, Kang H B-type natriuretic peptide: Issues for the intensivist and pulmonologist [Review Articles] Critical Care Medicine:Volume 33(9)September 2005pp 2094 -2013

2) de Lemos JA, McGuire DK, Drazner MH. B-type natriuretic peptide in cardiovascular disease. Lancet 2003;362:316-322.

3) Wang TJ, Larson MG, Levy D, et al. Plasma natriuretic peptide levels and the risk of cardiovascular events and death. N Engl J Med 2004;350:655-663

Dear Editor,

One of the wonders of emergency medicine is that there are almost as many different causes of injury as there are injury types. It is therefore not surprising that there are a myriad of case reports in the literature describing unusual objects causing injury. However, some stories have already been told.

I read the case report by Stables et al entitled “An unusual case of a compound depressed skull fracture after an assault with a stiletto heel” in the April 2005 issue of the Emergency Medicine Journal, and was struck with the thought that this must have been described before. How could we have come through “The Swinging 60’s” without this incident having occurred? Indeed, after a very brief search of “Google” using the keywords from the article ‘skull fracture ; stiletto heel’, the third result is of a case report in the British Medical Journal by Ahmed on “Stiletto Heel penetrating fractures of the skull” dated 1964.

This highlights two important points. Firstly, it is important to remember that the regular Medline database only includes articles from 1966 to the present day, and it is necessary to search OldMedline for articles prior to 1966, or use Google as an obliging alternative.

Secondly, don’t aggravate a girl with stiletto heels.

PLEASE NOTE THIS IS A RESUBMISSION FOR PRINTING PURPOSES WITH THE NECESSARY PERMISSIONS AS REQUESTED EMERMED/2008/069971 - Notify Author Re: Deficiencies

We read with interest this article by Shavit et al comparing the Alder Hey Triage Pain Score with a subjective scoring tool. The finding of a discrepancy in scoring between the tools, with the AHTPS scoring lower, is entirely consistent with the similar finding we reported in our paper (archdischild.2004;89;625-630). The conclusion drawn by the authors that this indicates that observational scoring should not be recommended is not justified. The findings may reflect the fact that the observational tool is not fully refined and the weighting for the different elements needs further research and development.

In the Shavit study pain scores were lower at triage assessment than in the waiting room. It was suggested that the reason for this was that Triage was a more reassuring environment. The inference made from this is that pain scoring is significantly influenced by anxiety. However, while this is likely, a subjective tool would be more affected by anxiety than an observational tool (AHTPS) and indeed the difference between the scores in the different settings reflected this. In order to eliminate as much of the anxiety element as possible subjective tools were initially developed in the situation of recurrent or procedural pain on the basis that there is an opportunity to explain the scoring tool prior to the painful event. This is not the case with children presenting at the ED with acute pain, which is why we do not think this type of scoring is appropriate for the ED setting where children in pain cannot be expected to consider and accurately interpret a new task. In addition there are some children who deny pain on subjective tools because of fear. This is why we still maintain that subjective scoring is inappropriate for A&E Triage. We also believe that it is possible that our tool underestimates pain and that it requires further research and refinement especially to re examine the parameters of the tool and their relative values to see how it can be improved. This area should be further explored before such methods are rejected. The need for a valid pain scoring tool is to indicate the appropriate level of analgesia to be prescribed. We acknowledge that the area of pain assessment is very complex and are committed to providing the best pain management to all children and would welcome interest, from others, in work to further refine the AHTPS. "The Corresponding Author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive licence (or non exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd and its Licensees to permit this article (if accepted) to be published in EMJ editions and any other BMJPGL products to exploit all subsidiary rights, as set out in our licence(http://emj.bmjjournals.com/ifora/licence.dtl)."

Competing Interest Please list Competing Interests if they exist, if not please include the

following statement; Competing Interest: None to declare.