Two cases of failed cardioversion of SVT after tibial intraosseous administration of adenosine in infants are described in this month’s Pediatric Emergency Care. Both cases were subsequently cardioverted by intravenous adenosine. The maximum intraosseous dose given was 0.25 mg/kg. The successful IV doses were not higher than the IO doses.
It has been noted before that infants may require relatively higher doses of adenosine than children and that 0.2 mg/kg might even be considered a starting dose in infancy. I wonder if a bigger IO dose would have been effective, or whether a proximal humeral insertion site would make a difference. IO adenosine has been successfully used in infants and piglets.
This interesting case series provides a helpful caution in the management of paediatric SVT.
ABSTRACT: Supraventricular tachycardia (SVT) is a common tachyarrhythmia in the pediatric population that can necessitate immediate treatment. Adenosine has been well studied as a mainstay treatment, but the methods of adenosine administration have not been very well delineated. The intraosseous technique has presented itself as a possible method of administration. We describe 2 cases in which adenosine was administered through bone marrow infusion to convert SVT without success. The cases we describe show that intraosseous is not a reliable method of administering adenosine to stop SVT. Both patients presented with SVT refractory to vagal maneuvers and difficult intravenous placement. Intraosseous access was achieved, but administration of adenosine at increasing doses was unable to successfully convert the arrhythmia.
Intraosseous Infusion Is Unreliable for Adenosine Delivery in the Treatment of Supraventricular Tachycardia
Pediatr Emerg Care. 2012 Jan;28(1):47-8
In febrile children, peripheral white blood cell counts were not helpful in separating children with self limiting infections from those with serious bacterial infections, but serum C reactive protein was1: febrile children with serum C reactive protein concentrations of 20 mg/L or less have a 5% risk of serious infection, whereas those with serum concentrations greater than 80 mg/L have a risk of 72%; children with intermediate values have a risk of about 15%. According to the accompanying BMJ editorial2:
This grouping, although imperfect, provides some guidance to help clinicians deciding which children may avoid extensive evaluation and treatment.
OBJECTIVE: To collate all available evidence on the diagnostic value of laboratory tests for the diagnosis of serious infections in febrile children in ambulatory settings.
DESIGN: Systematic review.
DATA SOURCES: Electronic databases, reference tracking, and consultation with experts.
STUDY SELECTION: Studies were selected on six criteria: design (studies of diagnostic accuracy or deriving prediction rules), participants (otherwise healthy children and adolescents aged 1 month to 18 years), setting (first contact ambulatory care), outcome (serious infection), features assessed (in first contact care), and data reported (sufficient to construct a 2×2 table).
DATA EXTRACTION: Quality assessment was based on the quality assessment tool of diagnostic accuracy studies (QUADAS) criteria. Meta-analyses were done using the bivariate random effects method and hierarchical summary receiver operating characteristic curves for studies with multiple thresholds.
DATA SYNTHESIS: None of the 14 studies identified were of high methodological quality and all were carried out in an emergency department or paediatric assessment unit. The prevalence of serious infections ranged from 4.5% to 29.3%. Tests were carried out for C reactive protein (five studies), procalcitonin (three), erythrocyte sedimentation rate (one), interleukins (two), white blood cell count (seven), absolute neutrophil count (two), band count (three), and left shift (one). The tests providing most diagnostic value were C reactive protein and procalcitonin. Bivariate random effects meta-analysis (five studies, 1379 children) for C reactive protein yielded a pooled positive likelihood ratio of 3.15 (95% confidence interval 2.67 to 3.71) and a pooled negative likelihood ratio of 0.33 (0.22 to 0.49). To rule in serious infection, cut-off levels of 2 ng/mL for procalcitonin (two studies, positive likelihood ratio 13.7, 7.4 to 25.3 and 3.6, 1.4 to 8.9) and 80 mg/L for C reactive protein (one study, positive likelihood ratio 8.4, 5.1 to 14.1) are recommended; lower cut-off values of 0.5 ng/mL for procalcitonin or 20 mg/L for C reactive protein are necessary to rule out serious infection. White blood cell indicators are less valuable than inflammatory markers for ruling in serious infection (positive likelihood ratio 0.87-2.43), and have no value for ruling out serious infection (negative likelihood ratio 0.61-1.14). The best performing clinical decision rule (recently validated in an independent dataset) combines testing for C reactive protein, procalcitonin, and urinalysis and has a positive likelihood ratio of 4.92 (3.26 to 7.43) and a negative likelihood ratio of 0.07 (0.02 to 0.27).
CONCLUSION: Measuring inflammatory markers in an emergency department setting can be diagnostically useful, but clinicians should apply different cut-off values depending on whether they are trying to rule in or rule out serious infection. Measuring white blood cell count is less useful for ruling in serious infection and not useful for ruling out serious infection. More rigorous studies are needed, including studies in primary care, to assess the value of laboratory tests alongside clinical diagnostic measurements, including vital signs.
1. Diagnostic value of laboratory tests in identifying serious infections in febrile children: systematic review
BMJ. 2011 Jun 8;342:d3082
2. How useful are laboratory tests in diagnosing serious infections in febrile children?
BMJ. 2011 Jun 8;342:d2782
Australian and New Zealand resuscitation councils have now revealed their resuscitation guidelines for adults and children. The index of guidelines can be found here
The Australian Resuscitation Council Online Index of Guidelines December 2010
An Iranian study showed 10% of afebrile well appearing infants had petechiae and they remained well on follow up. This is in keeping with previous studies on both afebrile and well-appearing febrile infants.
Prevalence and location of petechial spots in well infants
Arch Dis Child. 2010 Jul;95(7):518-20
A child with status epilepticus has been stabilised and intubated and is awaiting admission to the paediatric intensive care unit. You decide to insert a nasogastric tube. The nurse asks the following questions:
1. What size gastric tube would you like?
[EXPAND Answer]A general guide is twice the size of the uncuffed tracheal tube.
A four year old for example would usually need a tracheal tube size of 5.0mm internal diameter (age/4 +4), so would need a 10 Fr gastric tube.
2. To what length are you intending to insert it?
[EXPAND Answer]A formula based on height of the child can be used, so get your tape measure or length chart out:
For neonates < 2 weeks and children >8 years 4 months a method called NEMU (nose-ear-midxiphoid-umbilicus measurement) may be used.
3. How will you confirm placement?
[EXPAND Answer]It is very likely this child will get a post-intubation chest radiograph and the gastric tube tip can be visualised on that. However non-radiological tests should be used and pH testing of the aspirate is recommended, looking for pH<6
Further details on these measurements including positive and negative likelihood ratios of pH testing can be found in the evidence-based guideline from Cincinnati Children’s Hospital