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
Category Archives: All Updates
Pre-hospital amputation
British trauma surgeon and pre-hospital pioneer Professor Keith Porter describes how to do a pre-hospital amputation in this months EMJ. Thankfully the procedure is only rarely necessary and often only requires cutting remaining skin bridges with scissors. The indications are:
- An immediate and real risk to the patient’s life due to a scene safety emergency
- A deteriorating patient physically trapped by a limb when they will almost certainly die during the time taken to secure extrication
- A completely mutilated non-survivable limb retaining minimal attachment, which is delaying extrication and evacuation from the scene in a non-immediate life-threatening situation
- The patient is dead and their limbs are blocking access to potentially live casualties
The recommended procedure is:
- Ketamine anaesthesia
- Apply an effective proximal tourniquet
- Amputate as distally as possible
- Perform a guillotine amputation
- Apply haemostats to large blood vessels
- Leave the tourniquet in situ
- Apply a padded dressing and transport to hospital
Remember: the requirement for prehospital amputation other than cutting minimal soft tissue bridges is rare. However pre-hospital critical care physicians should be trained and equipped to amputate limbs in order to save life. Probably good to have a Gigli saw in your pack and to familiarise yourself with its use, as shown here:
Prehospital amputation
Emerg Med J 2010 27: 940-942
Pelvic splint improved shock
Splinted any pelvises lately? Karim Brohi’s excellent trauma.org article outlines the strengths and weaknesses of the different devices on the market. One such is the T-POD, which has now been described in a small series in which its application to patients with unstable pelvic injury was associated with improved haemodynamics and decreased symphyseal diastasis.
Here’s a video demonstrating application of the device.
Effect of a new pelvic stabilizer (T-POD1) on reduction of pelvic volume and haemodynamic stability in unstable pelvic fractures
Injury Volume 41, Issue 12, December 2010, Pages 1239-1243 (Full text)
'AMI' on ICU
ECG machines may give a printed report saying ***ACUTE MI***. In a retrospective study, patients on the ICU whose 12 lead ECGs contained this electronic interpretation did not have an elevated troponin 85% of the time. Even in the minority of patients whose electronic ECG diagnosis of MI was agreed with by a cardiologist, only one third developed an elevated troponin.
The authors state ‘In contrast to nonintensive care unit patients who present with chest pain, the electrocardiographic ST-segment elevation myocardial infarction diagnosis seems to be a nonspecific finding in the intensive care unit that is frequently the result of a variety of nonischaemic processes. The vast majority of such patients do not have frank ST-segment elevation myocardial infarction.’
Electrocardiographic ST-segment elevation myocardial infarction in critically ill patients: An observational cohort analysis
Crit Care Med. 2010 Dec;38(12):2304-230
Massive haemorrhage guideline
The Association of Anaesthetists of Great Britain and Ireland has published guidelines on the management of massive haemorrhage. Their summary:
- Hospitals must have a major haemorrhage protocol in place and this should include clinical, laboratory and logistic responses.
- Immediate control of obvious bleeding is of paramount importance (pressure, tourniquet, haemostatic dressings).
- The major haemorrhage protocol must be mobilised immediately when a massive haemorrhage situation is declared.
- A fibrinogen < 1 g.l)1 or a prothrombin time (PT) and activated partial thromboplastin time (aPTT) of > 1.5 times normal represents established haemostatic failure and is predictive of microvascular bleeding. Early infusion of fresh frozen plasma (FFP; 15 ml.kg)1) should be used to prevent this occurring if a senior clinician anticipates a massive haemorrhage.
- Established coagulopathy will require more than 15 ml.kg)1 of FFP to correct. The most effective way to achieve fibrinogen replacement rapidly is by giving fibrinogen concentrate or cryoprecipitate if fibrinogen is unavailable.
- 1:1:1 red cell:FFP:platelet regimens, as used by the military, are reserved for the most severely traumatised patients.
- A minimum target platelet count of 75 · 109.l)1 is appropriate in this clinical situation.
- Group-specific blood can be issued without performing an antibody screen because patients will have minimal circulating antibodies. O negative blood should only be used if blood is needed immediately.
- In hospitals where the need to treat massive haemorrhage is frequent, the use of locally developed shock packs may be helpful.
- Standard venous thromboprophylaxis should be commenced as soon as possible after haemostasis has been secured as patients develop a prothrombotic state following massive haemorrhage.
Blood transfusion and the anaesthetist: management of massive haemorrhage – full document
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
The Heart Point Sign
A case report describes the echo findings of a patient with a traumatic left sided pneumothorax. Although the subcostal view was unremarkable, upon imaging the parasternal region, the sonographer noted a flickering phenomenon where the heart was clearly visualized in late diastole, but would disappear in mid- systole only to reappear in late diastole during the next cardiac cycle. This ‘‘heart point’’ sign occurs because as the heart fills with blood in diastole, it enlarges and displaces the air from the precardiac space, allowing the heart to transiently contact the chest wall and be visualized with US. As the heart contracts during systole, the pneumothorax fills the space between the heart and the anterior chest wall, preventing the transmission of US and causing the heart to momentarily disappear from view.
The Heart Point Sign: Description of a New Ultrasound Finding Suggesting Pneumothorax
Academic Emergency Medicine 2010;17(11):e149–e150
Venous gas in COPD exacerbation
Prolific emergency medicine researcher Anne-Maree Kelly and colleague Dr Lim from Tan Tock Seng Hospital in Singapore have published a systematic review of articles assessing the utility of peripheral venous blood gases (pVBG) in exacerbations of COPD1. Their conclusion:
Available evidence suggests that there is good agreement for pH and HCO3 values between arterial and pVBG results in patients with COPD, but not for pO2 or pCO2. Widespread clinical use is limited because of the lack of validation studies on clinical outcomes
pVBG may however be useful as a screening test for significant arterial hypercarbia; Kelly et al. previously reported2 a cutoff value of 45 mmHg (5.9 kPa).
1. A meta-analysis on the utility of peripheral venous blood gas analyses in exacerbations of chronic obstructive pulmonary disease in the emergency department
Eur J Emerg Med. 2010 Oct;17(5):246-8
2. Kelly AM, Kerr D, Middleton P. Validation of venous pCO2 to screen for arterial hypercarbia in patients with chronic obstructive airways disease.
J Emerg Med 2005; 28:377–379
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
Echocardiography videos from Vienna
Folks from the Medical University of Vienna have produced a great resource with free online echocardiography videos at www.123sonography.com
Check out their video on right heart endocarditis: