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Re: Neuromuscular blockers in compasionate care

Verhagen et al describe the use of analgesics, sedatives and neuromuscular blockers during reorientation of care to compassionate measures in Groningen, the Netherlands (1). The authors draw attention to the fact that in 16% of such events, neuromuscular blockers (NMBs) were used. In cases, NMBs were used to eliminate gasping after the endotracheal tube had been removed. Diagnoses and reasons for administering NMBs after the decision to reorient care are described in 55 infants in the study. In two cases it was to prevent gasping, in 14 to stop established gasping and in one case the reason is stated as “to end life”. Futhermore, it was described as requested by parents in 2 cases. Dr Ward Platt has written a thoughtful editorial about this retrospective Dutch survey (2). He writes, “In the UK and perhaps elsewhere I suspect that the administration of such agents to a baby not already paralysed would be much less likely because it is more difficult to justify the use of NMBs on the basis of “double effect”. Because Archives of Diseases in Childhood is the Journal of the United Kingdom’s RCPCH, we feel it is important to make clear that administration of NMBs after extubation of a patient is currently illegal. Double effect might be argued in the event of administering intravenous sedatives. The used of NMBs after assisted ventilation has been withdrawn has the single purpose of ending respirations, thus bringing about the patient’s death.

C Piyasena, IA Laing. Neonatal Unit, Simpson Centre for Reproductive Health, Royal Infirmary of Edinburgh, EH16 4SA Correspondence to: Dr I A Laing, Neonatal Unit, Simpson Centre for Reproductive Health, Royal Infirmary of Edinburgh, EH16 4SA Competing interests: None

REFERENCES

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Re: Further evidence in support of the eyelid speculum as the cause of distress during screening for ret

dear editor,

Many procedural interventions remain a burden as they result in pain or discomfort in neonates. Adequate management of pain necessitates an integrated approach. Such an approach should also include the use of the most effective methods to perform a given procedure. [1] We therefore appreciate the paper on the randomized comparison between binocular indirect ophthalmoscopy (BIO) and wide-field digital retinal imaging (WFDRI) recently published by Dhaliwal et al. in this journal. [2] Based on observations collected in 76 infants, the authors concluded that both techniques resulted in a similar pain response and speculated that the pain during screening for retinopathy of prematurity was mainly due to the introduction of the speculum. We recently also reported on the clinical pain response during BIO and compared these observations with the outcome variables as described by Belda et al. [3,4] However, instead of the classic scleral indentation technique as used by Belda et al. and by Dhaliwal et al., the eyelid was kept open with a 20 diopter lens (Fabrilens). [5] A blunted clinical stress response was observed with a faster return to baseline in neonates in whom the Fabrilens was used since CRIES score returned to pre- intervention values within 5 minutes while changes in cardiovascular indicators were less prominent. We therefore confirm the hypothesis formulated by Dhaliwal et al. that indeed the introduction of the eyelid speculum results in the pain response. In addition to the prospective validation of various (non)pharmacological interventions for procedural pain relief, there is extensive field of prospective evaluation of various procedural techniques waiting for neonatal caregivers, nurses and doctors, to generate the data urgently needed reduce the pain and stress associated with the medical and nursing care in neonates.

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Re: The exact negative predictive value of procalcitonin remains to be determined

Dear Sir

I am writing this letter in reference to the article "Rapid quantitative procalcitonin measurement to diagnose nosocomial infections in newborn infants" by Jacquot et al. [1] The aim of this study was to investigate the diagnostic accuracy of procalcitonin in neonatal nosocomial infections. However, the flawed methodology and the incomplete reporting preclude a reliable conclusion with respect to the diagnostic performance of procalcitonin for ruling out nosocomial sepsis.

With an eye to the study objective, the power calculation should have been based on the expected sensitivity, specificity, predictive accuracy and their minimal acceptable lower confidence limit. [2,3] The authors omitted to report the 95% confidence interval for the estimates of sensitivity and negative predictive value. This prevents the reader of appreciating the range within which the true values are likely to lie [4]. Therefore, I backward calculated the true positive (30), false positive (15), false negative (0), and true negative (28) test results. Using a commercial statistical package (Prism 5.0 GraphPad software, San Diego, CA, USA), the sensitivity (95% CI) can be calculated to be 1 (0.8843 to 1) whereas the accuracy of a negative test is 1 (0.8766 to 1).

As yet, given this (im)precision, procalcitonin cannot be used to rule out nosocomial infection in the NICU at the moment of suspicion.

References:

1. Jacquot A, Labaune JM, Baum TP, Putet G, Picaud JC. Rapid quantitative procalcitonin measurement to diagnose nosocomial infections in newborn infants. Arch Dis Child Fetal Neonatal Ed 2009;94:F345-8.

2. Flahault A, Cadilhac M, Thomas G. Sample size calculation should be performed for design accuracy in diagnostic test studies. J Clin Epidemiol 2005;58:859-62.

3. Buderer NM. Statistical methodology: I. Incorporating the prevalence of disease into the sample size calculation for sensitivity and specificity. Acad Emerg Med 1996;3:895-900.

4. Harper R, Reeves B. Reporting of precision of estimates for diagnostic accuracy: a review. BMJ 1999;318:1322-3.