Dr WFS Sellers and colleagues describe several cases that demonstrate convincingly a protective effect of intravenous magnesium sulphate against the tachycardia produced by intravenous salbutamol in patients with asthma. This effect was observed both when magnesium was given before and when given after the salbutamol. It was seen in critically ill asthmatic patients and in a volunteer with well-controlled asthma.
Intravenous magnesium sulphate increases atrial contraction time and refractory times. It is used to treat atrial tachyarrhythmias and has a negative chronotropic and dromotropic effect.
Intravenous magnesium sulphate prevents intravenous salbutamol tachycardia in asthma
Br J Anaesth. 2010 Dec;105(6):869-70
Category Archives: Kids
Acute Paediatrics
Hypertonic saline in bronchiolitis
A Canadian randomised controlled trial compared nebulised 3% saline with 0.9% saline in 81 infants under 2 years of age with bronchiolitis. The short-term use of nebulised 3% saline did not result in any statistically significant benefits, although a non-significant trend toward a decrease in hospital admission and improvement in respiratory distress was found. A larger study would be required to determine whether these trends arise from a clinically relevant treatment effect.
There’s really not much that’s been shown to make a difference in this disease, as this review article reminds us.
Effect of inhaled hypertonic saline on hospital admission rate in children with viral bronchiolitis: a randomized trial.
CJEM. 2010 Nov;12(6):477-84
Aorta/IVC ratio and dehydration
Two studies this month report a correlation between ultrasound detected aorta/IVC ratio and dehydration in children presenting with diarrhoea and/or vomiting. In both studies the IVC diameter was measured in expiration and the aortic diameter in systole, using a transverse view in the subxiphoid area. Both used acute and post-discharge weight comparison to ascertain degree of dehydration.
The first study took place in Rwanda and a percent weight change between admission and discharge of greater than 10% was considered the criterion standard for severe dehydration. 52 children were included ranging in age from 1 month to 10 year. Vessel diameter measurements were inner wall to inner wall. The IVC-to-aorta ratio correlated significantly with percent weight change (r = 0.435, p < 0.001). Using the best ROC curve cutoff of 1.22, aorta/IVC ratio had a sensitivity of 93% (95% CI = 81% to 100%), specificity of 59% (95% CI = 44% to 75%), LR+ of 2.3 (95%CI=1.5to3.5), and LR– of 0.11 (95%CI=0.02to 0.76) for detecting severe dehydration. The same study did not find ultrasound assessment of inferior vena cava inspiratory collapse or the World Health Organization scale to be accurate predictors of severe dehydration in this same population of children.
Ultrasound Assessment of Severe Dehydration in Children With Diarrhea and Vomiting
Acad Emerg Med. 2010 Oct;17(10):1035-41
The second study took place in the USA. The subjects were considered to have significant dehydration if the weight loss was at least 5%. 71 were children were included. The area under the curve (AUC) was 0.73 (95% CI = 0.61 to 0.84). An IVC ⁄ aorta cutoff of 0.8 produced a sensitivity of 86% and a specificity of 56% for the diagnosis of significant dehydration. The positive predictive value was 56%, and the negative predictive value was 86%. Note this equates to an aorta/IVC ratio of 1.25, similar to that in the first study.
My rough-and-ready take home message from these two studies appears to be that an aorta/IVC ratio less than about 1.2 makes severe dehydration less likely in children with symptoms of gastroenteritis.
Use of Bedside Ultrasound to Assess Degree of Dehydration in Children With Gastroenteritis
Acad Emerg Med. 2010 Oct;17(10):1042-7
Propofol for kids in the ED
A systematic review of the use of propofol for paediatric procedural sedation (PPS) identified sixty studies and 17 066 published paediatric propofol sedations performed outside the operating theatre setting. The incidence of complications were: desaturation 9.3%, apnoea 1.9%, assisted ventilation 1.4%, hypotension 15.4%, unplanned intubation 0.02%, emesis post procedure 0.14%, laryngospasm 0.1% and bradycardia 0.1%. There are many confounding variables that influence the likelihood of these events: adjunct opiates, propofol dosing strategies and supplemental oxygen. These rates of minor adverse events are similar to that published for ED sedation with other sedation agents
There were no reported incidents of aspiration or emesis during sedation and there were no deaths associated with procedural propofol sedation. The authors conclude: “the published adverse event data for paediatric propofol sedation support its ongoing use in the ED for appropriately selected paediatric patients by experienced physicians who are able to provide advanced cardiorespiratory support.”
Review article: Safety profile of propofol for paediatric procedural sedation in the emergency department
Emerg Med Australas. 2010 Aug;22(4):265-86
Paediatric arrest outcomes
A study of out-of-hospital paediatric arrests in Melbourne gives some useful outcome data: overall, paediatric victims of out-of-hospital cardiac arrest survived to leave hospital in 7.7% of cases, which is similar to adult survival in the same emergency system (8%). Survival was very rare (<1%) unless there was return of spontaneous circulation prior to hospital arrival. Sixteen of the 193 cases studied had trauma, but the survival in this subgroup was not specifically documented.
Epidemiology of paediatric out-of-hospital cardiac arrest in Melbourne, Australia
Resuscitation. 2010 Sep;81(9):1095-100
AED Use in Children Now Includes Infants
From the new 2010 resuscitation guidelines:
For attempted defibrillation of children 1 to 8 years of age with an AED, the rescuer should use a pediatric dose-attenuator system if one is available. If the rescuer provides CPR to a child in cardiac arrest and does not have an AED with a pediatric dose-attenuator system, the rescuer should use a standard AED. For infants (<1 year of age), a manual defibrillator is preferred. If a manual defibrillator is not available, an AED with pediatric dose attenuation is desirable. If neither is available, an AED without a dose attenuator may be used.
Summary: Adult AEDs may be used in all infants and children if there is no child-specific alternative
Highlights of the 2010 American Heart Association Guidelines for CPR and ECC
Resuscitation Guideline Changes
The European Resuscitation Council’s Summary of Major Changes in the 2010 guidelines can be downloaded here
New CPR Guidelines
The International Liaison Committee on Resuscitation has published its five-yearly update of resuscitation guidelines.
The American Heart Association Guidelines can be accessed here
The European Resuscitation Guidelines can be accessed here
2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science
Circulation. 2010;122:S639
Two smaller lines may be quicker
Using Poiseuille’s law and standardized gauge sizes, an 18-gauge (g) intravenous catheter (IV) should be 2.5 times faster than a 20-g IV, but this is not borne out by observation, in vitro testing, and manufacturer’s data. A nice simple study on normal volunteers compared simultaneous flow rates between a single 18G iv in one arm with two 20G ivs in the other arm. The two smaller ones provided significantly faster flow than the single larger one, although flow rates were slower than manufacturer’s estimates. This is in keeping with this other study on cannula flow rates.
Are 2 smaller intravenous catheters as good as 1 larger intravenous catheter?
Am J Emerg Med. 2010 Jul;28(6):724-7
Peripheral vasoactive infusions
It is often recommended that vasoactive agents are infused via central lines because of the risk of infiltration and tissue injury. The Children’s Hospital Boston transport team describe transport of 73 infants and children who were treated during interhospital transport with vasoactive medications via a peripheral intravenous line.
Median transport time was only 38 minutes (range 3[!!]-216) and median age was 1 (birth to 19) .
Dopamine monotherapy was given in 66 patients, adrenaline (epinephrine) monotherapy in 2, dobutamine plus phenylephrine in 1, dopamine and epinephrine in 3, and dopamine, dobutamine, and epinephrine in 1 patient.
In this retrospective study no patients developed infiltration or other complications related to peripheral vasoactive agents during interfacility transport. Eleven of the 73 patients, however, did develop infiltrates related to vasoactive infusion after arrival at the accepting institution; all infiltrates involved only minimal blanching and/or erythema, and all resolved without significant intervention and caused no lasting tissue injury. The risk of infiltration rose with increasing medication dose and duration of use.
Interesting that noradrenaline (norepinephrine) wasn’t used. This study is interesting but the overwhelming predominance of dopamine makes it hard to extrapolate this to European or Australasian practice.
The Use of Vasoactive Agents Via Peripheral Intravenous Access During Transport of Critically Ill Infants and Children
Pediatr Emerg Care. 2010 Aug;26(8):563-6