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Towards evidence based medicine for paediatricians

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In order to give the best care to patients and families, paediatricians need to integrate the highest quality scientific evidence with clinical expertise and the opinions of the family.1 Archimedes seeks to assist practising clinicians by providing “evidence based” answers to common questions which are not at the forefront of research but are at the core of practice. They are based on an original format from theJournal of Accident and Emergency Medicine.2

A word of warning. These best evidence topic summaries (BETs) are not systematic reviews, though they are as exhaustive as a practising clinician can produce. They make no attempt to statistically aggregate the data, nor search the grey, unpublished literature. WhatArchimedes offers are practical, best evidence based answers to practical, clinical questions.

Each topic follows the same format. A description of the clinical setting is followed by a structured clinical question. (These aid in focusing the mind, assisting searching,3 and gaining answers.4) A brief report of the search used follows—this has been performed in a hierarchical way, to search for the best quality evidence to answer the question.5 A table provides a summary of the evidence and key points of the critical appraisal. For further information on critical appraisal, and the measures of effect (such as number needed to treat, NNT) books by Sackett6and Moyer7 may help. A commentary is provided to pull the information together, and for accessibility, a box provides the clinical bottom lines.

Readers wishing to submit their own questions—with best evidence answers—are encouraged to read the Instructions for Authors athttp://archdischild.com. Three topics are covered in this issue of the journal.  

  • Is silver nitrate the best agent for management of umbilical granulomas?

  • Does adding ipratropium to salbutamol help children with asthma?

  • Should tympanic temperature measurement be trusted?

References

Concealed, blinded, or masked?

In the anatomy of randomised controlled trials, the words blinding, masking, and concealment are commonly used. They are commonly misunderstood—and this has important consequences.  Blinding(or masking) is the process of obscuring to patient, observer, or both the treatment to which they are allocated. It relies on two therapies having no clearly discernible effects to “unmask” the allocation. Some of these may be thought about prior to the trial (such as the bradycardia of β blockers) but some are more surprising to investigators (during an early trial of HIV therapy, participants in the trial found half the capsules floated, half sank).

Concealment refers to the security of the randomisation list. Before a patient is offered a place on a trial, there should be no way of the investigator knowing which treatment the patient will receive. A trial may be well concealed, although impossible to blind, for example, Hi-Fi trial. why bother? Schulz1-1 looked at factors which appeared to affect the results of studies of therapy. Those trials which gave the most exaggerated effects had no allocation concealment. The factor of blinding had a less dramatic effect. 1  Schulz KF. Randomised trials, human nature and reporting guidelines.Lancet1996;348:596–8.

Is silver nitrate the best agent for management of umbilical granulomas?

Scenario

A mother brings her 2 week old baby to your clinic. The child has a small umbilical granuloma but is otherwise well. Should you use silver nitrate to cauterise the granuloma?

Structured clinical question

In a well, 2 week old neonate with an umbilical granuloma [patient], is silver nitrate cauterisation preferable to conservative treatment [intervention] in order to facilitate safe resolution of the granuloma [outcome]?

Search strategy and outcome

Secondary searches—Cochrane, Clinical evidence—none.

Medline 1966–2001, using the OVID interface.

1.
Silver nitrate.tw
2.
Clinical trial limit, 1+2 found: 36 papers, of which none were relevant.
3.
Umbilic$.tw, , 1+3 found: 10 papers, 1 highlighting complications, 1 was a comment on this paper, 1 discussing the use of salt; 7 were irrelevant.

Summary

See table 1-1.

Table 1-1

Commentary

The above papers suggest umbilical granulomas may be self limiting and resolve with conservative management such as the application of salt. They also suggest that application of silver nitrate is not without risk.

Clinical bottom line

  • Silver nitrate may be dangerous—it can cause burns

  • Conservative management involving salt may be just as successful

Anecdotal evidence suggests that cleaning with Steret alcoholic wipes may be as effective as salt. If they are used, they should be applied at each nappy change. It may also be beneficial to fold the front of the nappy to expose the umbilicus.

No randomised controlled trials have been performed to investigate whether conservative management is as effective as silver nitrate. A randomised controlled trial to investigate this is being planned.

Author

Justin Daniels (Paediatric Registrar, North Middlesex Hospital) [justin.daniels{at}virgin.net]

References

  1. 1-1.
  2. 1-2.

Does adding ipratropium to salbutamol (albuterol) help children with asthma?

Scenario

A 9 year old girl attended her general practitioner with a moderate to severe exacerbation of asthma. Initial treatment included nebulised salbutamol (albuterol) and oral steroids. She was admitted to hospital, and treated with salbutamol, ipratropium, and oxygen. In the morning, a consultant comments “Ipratropium? I've always found that doesn't work.”

Structured clinical question

In a 9 year old child with moderate to severe exacerbation of asthma [patient], does ipratropium and salbutamol (albuterol) [intervention] compared with salbutamol alone [comparison] improve clinical outcomes (admission rates, relapse, etc) [outcome]?

Search strategy and outcome

Secondary sources—Cochrane review—1 relevant.

SumSearch—“asthma” AND “ipratropium” AND filter “therapy” AND “child”.

Search results—36 original articles, 1 relevant and not in Cochrane review.

Summary

See table 2-2.

Table 2-2

Commentary

Pooling of studies in the systematic review has shown a significant reduction in hospitalisation rates for children with severe acute asthma treated with ipratropium added to β2agonists in a protocol of multiple fixed doses. Insufficient data exists on the effects of ipratropium in more flexible multiple dose regimes, which may more closely resemble the actual treatment of children with acute asthma.

The recent study by Craven et al confirms this trend of shorter hospitalisation, but with insufficient numbers of severe asthma sufferers to show statistical significance. Importantly only 43% of eligible children entered this study, creating a possible selection bias.

In mild and moderate acute asthma, ipratropium has not been shown to significantly improve outcome in terms of hospitalisation rates or length of stay, or clinical care path progression rate.

Authors

Neil Patel (Senior House Officer in Paediatrics, Royal Hospital for Sick Children, Glasgow) [neil_patel50{at}hotmail.com] Bob Phillips (Associate Fellow, Centre for Evidence-based Medicine, Oxford)

Clinical bottom line

  • In children with severe acute asthma, addition of ipratropium bromide to a multiple dosing regime of β2 agonists leads to a reduction in hospital admission rates (number needed to treat = 7, to prevent 1 admission), and a reduction in the need for additional doses of inhaled bronchodilator

  • In children with mild or moderate acute asthma, no significant benefit of ipratropium bromide has been shown

  • Single doses of ipratropium bromide do not significantly affect hospital admission rates, or the need for additional bronchodilators

References

  1. 2-1.
  2. 2-2.

Should tympanic temperature measurement be trusted?

Scenario

A 5 month old boy attends the emergency department with a history of fever given by his mother. His temperature as taken with a tympanic thermometer is 37.5°C. His mother says he is hot to the touch. He has no focus for his fever on examination. The departmental protocol recommends a full septic screen in this age group if the temperature is above 38°C. You would like to know how accurate temperatures taken by this method are, and whether you should check the temperature using another method.

Structured clinical question

In a 5 month old boy with a fever [patient], how accurate is tympanic thermometry [diagnosis] as a measure of core body temperature [outcome]?

Search strategy and outcome

Secondary sources—0. Systematic reviews—1. Original research—SumSearch “temperature measurement”, “child”, “fever” AND filter “diagnosis”—57 individual articles, 2 directly relevant.

Summary

See table 3-3.

Table 3-3

Commentary

Clinical bottom line

  • The diagnosis of fever without a focus should not be made based on tympanic thermometry as it is not an accurate measurement of core temperature

  • Rectal temperature measurement remains the clinical gold standard for diagnosis of fever in infants and children

The systematic review reported 44 studies addressing the use of different methods oftemperature measurement including, axillary, sublingual, tympanic, and rectal. Two further studies directly addressed the question of how representative tympanic measurements are of core temperature measurement. Both studies showed a correlation between tympanic and rectal methods of temperature measurement, although it was not strong enough to use as a basis to make decisions regarding clinical management.

Authors

Anna Riddell (Research Registrar, Oxford Vaccine Group) [anna.riddell{at}paediatrics.ox.ac.uk] Walter Eppich (Resident in Pediatrics, Duke University Medical Center)

References

  1. 3-1.
  2. 3-2.
  3. 3-3.
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