A thorough review of the emergency medicine sedation literature showed there is only one reported case of pulmonary aspiration during emergency procedural sedation, among 4657 adult cases and 17 672 paediatric cases reviewed. The authors of the review remind us that the often (inappropriately in the ED) quoted American Society of Anesthesiology guidelines for fasting prior to general anaesthesia are based on questionable evidence, and there is high-level evidence that demonstrates no link between pulmonary aspiration and non-fasted patients. There is no reason to recommend routine fasting prior to procedural sedation in the majority of patients in the Emergency Department.
An accompanying editorial points out that like other systematic reviews, the methodological flaws of the studies examined are likely to have limited the conclusions of this review.
The review authors and the editorialist agree that despite the lack of evidence linking fasting status to aspiration, selected patients believed to be significantly more prone to aspiration may benefit from risk:benefit assessment prior to sedation.
Something I learned from reading the review: ‘ it is now recognised that asymptomatic aspiration of gastric contents occurs physiologically during normal sleep‘. How about that.
Pre-procedural fasting in emergency sedation
Emerg Med J. 2010 Apr;27(4):254-61
Category Archives: All Updates
What fluid in rhabdomyolysis?
A ‘BestBET‘ from the Emergency Medicine Journal examined the evidence for the use of sodium bicarbonate and/or mannitol in the management of rhabdomyolysis.
The clinical bottom line: there is no quality published evidence that alkaline diuresis is a superior treatment to normal saline alone.
Rhabdomyolysis and the use of sodium bicarbonate and/or mannitol
Emerg Med J. 2010 Apr;27(4):305-8
Full Text at the BestBets site
Oxygen in AMI – no benefit, possible harm
A Cochrane review examined the evidence from randomised controlled trials to establish whether routine use of inhaled oxygen in acute myocardial infarction (AMI) improves patient-centred outcomes, the primary outcomes being death, pain and complications.
Three trials involving 387 patients were included and 14 deaths occurred. The pooled relative risk (RR) of death was 2.88 (95% CI 0.88 to 9.39) in an intention-to-treat analysis and 3.03 (95% CI 0.93 to 9.83) in patients with confirmed AMI. While suggestive of harm, the small number of deaths recorded meant that this could be a chance occurrence. Pain was measured by analgesic use. The pooled RR for the use of analgesics was 0.97 (95% CI 0.78 to 1.20).
There is therefore no conclusive evidence from randomised controlled trials to support the routine use of inhaled oxygen in patients with acute AMI. A definitive randomised controlled trial is required.
Oxygen therapy for acute myocardial infarction
Cochrane Review
B lines be gone!
Vicki Noble’s Emergency Ultrasound team describe the resolution of Songraphic B lines on the lung ultrasound of a patient with end stage renal disease who presented with dyspnoea due to pumonary oedema which was treated with CPAP.
B-lines are hyperechoic vertical lines that originate at and slide with the pleura and extend radially to the edge of the screen without fading. Isolated B-lines may be seen in normal lungs, but diffuse B-lines in multiple zones indicate interstitial thickening, most commonly seen in congestive heart failure (CHF).
This case is interesting because it describes real-time resolution of B-lines during therapy in the ED demonstrating that in CHF, B-lines reflect acute rather than chronic changes within lung parenchyma.
Real-time resolution of sonographic B-lines in a patient with pulmonary edema on continuous positive airway pressure
Am J Emerg Med. 2010 May;28(4):541.e5-8
Stroke thrombolysis benefit decays with time
Pooled results of several trials comparing recombinant tissue plasminogen activator with placebo in ischaemic stroke quantify the profile of benefit and harm for alteplase in broadly selected patients. Generally, alteplase appears to improve the outcome of one in three patients treated between 1 and 3 h from onset and of one in six patients treated in the 3–4·5 h window, but confers no net benefit beyond that time. Benefit may decrease exponentially (according to an accompanying editorial), so if you are a believer then get in there early.
Time to treatment with intravenous alteplase and outcome in stroke: an updated pooled analysis of ECASS, ATLANTIS, NINDS, and EPITHET trials
Lancet. 2010 May 15;375(9727):1695-703
Misoprostol for PPH
Misoprostol is a prostaglandin analogue with uterotonic activity. It was compared with placebo in its sublingual form in a randomised trial in 1422 women with postpartum haemorrhage and uterine atony. It was given with other uterotonic agents (mostly oxytocin 10IU im or slow iv). The primary outcome was blood loss of 500 mL or more within 60 min after randomisation, and this was similar in both groups.
Misoprostol as an adjunct to standard uterotonics for treatment of post-partum haemorrhage: a multicentre, double-blind randomised trial
Lancet. 2010 May 22;375(9728):1808-13
Lung Ultrasound Articles
Here are some sites that explain lung sonography as applied to critical care patients:
Clinical review: Bedside lung ultrasound in critical care practice – Critical Care Full Text
Evaluation of ultrasound lung comets by hand-held echocardiography – Cardiovascular Ultrasound Full Text
ICU Sonography Site – Lung Ultrasound Tutorial
HFOV in preterms – no clear benefit
Pre-term infants lacking surfactant often require mechanical ventilation, but the consequent barotrauma and volutrauma may contribute to chronic lung disease, or bronchopulmonary dysplasia. Consequently high frequency oscillatory ventilation (HFOV) has been tried, but results from trials are mixed. A new systematic review of 3229 preterm newborns of less than 35 weeks’ gestation in 10 randomised trials fails to show a benefit of HFOV over conventional ventilation.
Elective high-frequency oscillatory versus conventional ventilation in preterm infants: a systematic review and meta-analysis of individual patients’ data
The Lancet, Volume 375, Issue 9731, Pages 2082 – 2091, 12 June 201o
Exsanguinating pelvis – occlude the aorta
Some patients with life-threatening arterial haemorrhage from a pelvic fracture may be peri-arrest prior to transfer to the angiography suite. French authors describe their use of a balloon catheter to occlude the infrarenal aorta to allow resuscitation to achieve sufficient stability for the transfer. As well as exsanguinating pelvic haemorrhage, intra-aortic balloon occlusion has already been described for the treatment of hemorrhagic shock in the case of ruptured abdominal aortic aneurysm, in abdominal trauma, in gastrointestinal bleeding, and in postpartum hemorrhage.
Features of note regarding the technique include:
- it can be done blind (without radiological guidance)
- it can be done prior to transfer to a centre with interventional radiology
- it can be done in cardiac arrest (and has resulted in ROSC and subsequent survival)
The authors are at pains to point out that the intra-aortic balloon occlusion method described in the study ‘should be reserved to patients in critically uncontrollable hemorrhagic shock (CUHS) and is not a first-line treatment of pelvic fractures in hemorrhagic shock.’
Intra-Aortic Balloon Occlusion to Salvage Patients With Life-Threatening Hemorrhagic Shocks From Pelvic Fractures
J Trauma. 2010 Apr;68(4):942-8.
Tranexamic acid saves lives in trauma
A convincing, practice-changing trial is a rare thing in major trauma, but here comes a biggie:
The CRASH-2 trial recruited over 20 000 patients from 40 countries (sadly excluding the US because the trial investigators couldn’t afford the insurance – a sign that no large drug company was funding this trial of an inexpensive therapy).
The antifibrinolytic drug tranexamic acid was compared with placebo in adult trauma patients with, or thought to be at risk of, significant haemorrhage. Clinicians were blinded to the intervention and the primary outcome was death in hospital within 4 weeks of injury. Secondary outcomes were vascular occlusive events (myocardial infarction, stroke, pulmonary embolism, and deep vein thrombosis), surgical intervention (neurosurgery, thoracic, abdominal, and pelvic surgery), receipt of blood transfusion, and units of blood products transfused. Treatment groups were balanced with respect to all baseline patient characteristics.
All-cause mortality was significantly reduced with tranexamic acid and the risk of death due to bleeding was significantly reduced. Vascular occlusive events (fatal or non-fatal) did not differ significantly between the groups (and were fewer in the tranexamic acid group compared with the placebo group).
All cause mortality in the tranexamic acid group was (1463/10 060) = 14·5% and in the placebo group was (1613/10 067) = 16·0%. So absolute risk reduction is 1.5% and Number Needed to Treat = 67.
The same trials group is investigating the effect of tranexamic acid in post-partum haemorrhage, in a study known as the WOMAN Trial
Take Home Message: the early administration of tranexamic acid to trauma patients with, or at risk of, significant bleeding reduces the risk of death from haemorrhage with no apparent increase in fatal or non- fatal vascular occlusive events. All-cause mortality was significantly reduced with tranexamic acid.
Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial
The Lancet, Early Online Publication, 15 June 2010