Acute Med, All Updates, Guidelines, Resus

STEMI and PCI guidelines

Lots of interesting and up to date information in this thick document from December 2009
Full text is available here
2009 Focused Updates: ACC/AHA Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction (Updating the 2004 Guideline and 2007 Focused Update) and ACC/AHA/SCAI Guidelines on Percutaneous Coronary Intervention (Updating the 2005 Guideline and 2007 Focused Update)

Acute Med, All Updates, Resus

Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia

This disease may result in sudden cardiac death in young people, and the assessment of patients who present with dysrhythmias or syncope should prompt a review of the ECG for suggestive features of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (as well as ischaemia, conduction deficits, WPW syndrome, Brugada syndrome, and prolonged QT interval).
A Task force has revised its diagnostic criteria for the disease, listed as major and minor criteria pertaining to family history, ECG, echo, MRI, and angiographic features. The ECG features that front line doctors need to be on the look out for include:

  • Inverted T waves in right precordial leads (V1, V2, and V3) or beyond in individual >14 years of age (in the absence of complete right bundle-branch block QR>120 ms)
  • Inverted T waves in leads V1 and V2 in individual>14 years of age (in the absence of complete right bundle-branch block) or in V4, V5, or V6
  • Inverted T waves in leads V1, V2, V3, and V4 in individual>14 years of age in the presence of complete right bundle-branch block
  • Epsilon wave (reproducible low-amplitude signals between end of QRS complex to onset of the T wave) in the right precordial leads (V1 to V3)
Epsilon waves
  • Nonsustained or sustained ventricular tachycardia of left bundle-branch morphology with superior axis (negative or indeterminate QRS in leads II, III, and aVF and positive in lead aVL)
  • Nonsustained or sustained ventricular tachycardia of RV outflow configuration, left bundle-branch block morphology with inferior axis (positive QRS in leads II, III, and aVF and negative in lead aVL) or of unknown axis
  • >500 ventricular extrasystoles per 24 hours (Holter)

Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia Proposed Modification of the Task Force Criteria
Circulation. 2010 Apr 6;121(13):1533-41
More info on this disease from the European Society of Cardiology here

Acute Med, All Updates, ICU, Kids, Resus

Crystalloids vs colloids and cardiac output

It is said that when using crystalloids, two to four times more fluid may be required to restore and maintain intravascular fluid volume compared with colloids, although true evidence is scarce. The ratio in the SAFE study comparing albumin with saline resuscitation was 1:1.3, however.
A single-centre, single- blinded, randomized clinical trial was carried out on 24 critically ill sepsis and 24 non-sepsis patients with clinical hypovolaemia, assigned to loading with normal saline, gelatin 4%, hydroxyethyl starch 6% or albumin 5% in a 90-min (delta) central venous pressure (CVP)-guided fluid loading protocol. Haemodynamic monitoring using transpulmonary thermodilution was done each 30 min to measure, among other things, global end-diastolic volume and cardiac indices (GEDVI, CI). The reason sepsis was looked at was because of a suggestion in the SAFE study of benefit from albumin in the pre-defined sepsis subgroup.
Independent of underlying disease, CVP and GEDVI increased more after colloid than saline loading (P = 0.018), so that CI increased by about 2% after saline and 12% after colloid loading (P = 0.029).
Their results agree with the traditional (pre-SAFE) idea of ratios of crystalloid:colloid, since the difference in cardiac output increase multiplied by the difference in volume infused was three for colloids versus saline.
Take home message? Even though an outcome benefit has not yet been conclusively demonstrated, colloids such as albumin increase pre-load and cardiac index more effectively than equivalent volumes of crystalloid in hypovolaemic critically ill patients.
Greater cardiac response of colloid than saline fluid loading in septic and non-septic critically ill patients with clinical hypovolaemia
Intensive Care Med. 2010 Apr;36(4):697-701

Acute Med, All Updates, ICU, Resus

Magnesium for subarachnoid haemorrhage

Symptomatic cerebral vasospasm occurs in nearly one-third of patients with aneurysmal subarachnoid hemorrhage and is a major cause of disability and mortality in this population.
Magnesium (Mg) acts as a cerebral vasodilator by blocking the voltage-dependent calcium channels.. Experimental studies suggest that Mg also inhibits glutamate release by blocking N-methyl-D-aspartate receptors, decreases intracellular calcium influx, and increases red blood cell deformability; all these changes may reduce the occurrence of cerebral vasospasm and minimise brain ischemic injury occurring after SAH.
One hundred and ten patients within 96 hours of admission for aneurysmal subarachnoid haemorrhage (SAH) were randomised to receive iv magnesium or placebo. Nimodipine was not routinely given. Twelve patients (22%) in the magnesium group and 27 patients (51%) in the control group had delayed ischemic infarction – the primary endpoint (p< .0020; odds ratio [OR], 0.28; 95% confidence interval [CI], 0.12– 0.64). Mortality was lower and neurological outcome better in the magnesium group but these results were not statistically significant.
Larger trials of magnesium in SAH are ongoing.
Prophylactic intravenous magnesium sulfate for treatment of aneurysmal subarachnoid hemorrhage: A randomized, placebo-controlled, clinical study
Crit Care Med. 2010 May;38(5):1284-90
Update September 2012:
A multicentre RCT showed intravenous magnesium sulphate does not improve clinical outcome after aneurysmal subarachnoid haemorrhage, therefore routine administration of magnesium cannot be recommended.
Magnesium for aneurysmal subarachnoid haemorrhage (MASH-2): a randomised placebo-controlled trial
Lancet 2012 July 7; 380(9836): 44–49 Free full text
[EXPAND Click to read abstract]


Background Magnesium sulphate is a neuroprotective agent that might improve outcome after aneurysmal subarachnoid haemorrhage by reducing the occurrence or improving the outcome of delayed cerebral ischaemia. We did a trial to test whether magnesium therapy improves outcome after aneurysmal subarachnoid haemorrhage.

Methods We did this phase 3 randomised, placebo-controlled trial in eight centres in Europe and South America. We randomly assigned (with computer-generated random numbers, with permuted blocks of four, stratified by centre) patients aged 18 years or older with an aneurysmal pattern of subarachnoid haemorrhage on brain imaging who were admitted to hospital within 4 days of haemorrhage, to receive intravenous magnesium sulphate, 64 mmol/day, or placebo. We excluded patients with renal failure or bodyweight lower than 50 kg. Patients, treating physicians, and investigators assessing outcomes and analysing data were masked to the allocation. The primary outcome was poor outcome—defined as a score of 4–5 on the modified Rankin Scale—3 months after subarachnoid haemorrhage, or death. We analysed results by intention to treat. We also updated a previous meta-analysis of trials of magnesium treatment for aneurysmal subarachnoid haemorrhage. This study is registered with controlled-trials.com (ISRCTN 68742385) and the EU Clinical Trials Register (EudraCT 2006-003523-36).

Findings 1204 patients were enrolled, one of whom had his treatment allocation lost. 606 patients were assigned to the magnesium group (two lost to follow-up), 597 to the placebo (one lost to follow-up). 158 patients (26·2%) had poor outcome in the magnesium group compared with 151 (25·3%) in the placebo group (risk ratio [RR] 1·03, 95% CI 0·85–1·25). Our updated meta-analysis of seven randomised trials involving 2047 patients shows that magnesium is not superior to placebo for reduction of poor outcome after aneurysmal subarachnoid haemorrhage (RR 0·96, 95% CI 0·86–1·08).

Interpretation Intravenous magnesium sulphate does not improve clinical outcome after aneurysmal subarachnoid haemorrhage, therefore routine administration of magnesium cannot be recommended.

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All Updates, ICU, PHARM, Resus

Current Controversy in RSI

A review article in Anesthesia and Analgesia provides a summary of the literature surrounding RSI controversies.

  • Should a pre-determined dose of induction drug be given or should it be titrated to effect prior to giving suxamethonium?
  • Should fast acting opioids be coadministered to blunt the pressor response?
  • What is the optimal dose of suxamethonium?
  • Should defasciculating doses of neuromuscular blocking drugs be given?
  • What is the ‘priming’ technique with rocuronium and is it necessary?
  • Is it really bad to bag-mask ventilate the patient after induction prior to intubation? Which patients might this benefit?
  • Should patients with full stomachs be anaesthetised sitting up, supine, or head down?
  • Is cricoid pressure a good or a bad thing?

Not surprisingly the jury is still out on these, which is of course why they remain ‘controversies’. The review article provides a readable, interesting, and up to date summary of the evidence to date.

Rapid Sequence Induction and Intubation: Current Controversy
Anesth Analg. 2010 May 110(5):1318-25

All Updates, ICU, Resus

Inhaled NPA

A case is reported of a stroke patient who aspirated his nasopharyngeal airway, resulting in coughing and desaturation. After iv propofol and topical anaesthesia to the oropharynx and hypopharynx, it was seen on laryngoscopy to be within the trachea but could not be retrieved with Magill forceps. Instead, his doctors inserted a well lubricated 14 Fr foley catheter through the lumen of the tube, inflated the balloon, and pulled it out.
Retrieval of Aspirated Nasopharyngeal Airway Using Foley Catheter
Anesth Analg. 2010 Apr;110(4):1245-6

Fascinomata

A close look at the Sun

NASA’s recently launched Solar Dynamics Observatory, or SDO, is returning early images that confirm an unprecedented new capability for scientists to better understand our sun’s dynamic processes. These solar activities affect everything on Earth.
Some of the images from the spacecraft show never-before-seen detail of material streaming outward and away from sunspots. Others show extreme close-ups of activity on the sun’s surface. The spacecraft also has made the first high-resolution measurements of solar flares in a broad range of extreme ultraviolet wavelengths.
“These initial images show a dynamic sun that I had never seen in more than 40 years of solar research,” said Richard Fisher, director of the Heliophysics Division at NASA Headquarters in Washington. “SDO will change our understanding of the sun and its processes, which affect our lives and society. This mission will have a huge impact on science, similar to the impact of the Hubble Space Telescope on modern astrophysics.”

Launched on Feb. 11, 2010, SDO will provide images with clarity 10 times better than high-definition television. SDO will send 1.5 terabytes of data back to Earth each day, which is equivalent to a daily download of half a million songs onto an MP3 player.
The SDO “is shedding new light on our closest star, the sun, discovering new information about powerful solar flares that affect us here on Earth by damaging communication satellites and temporarily knocking out power grids. Better data means more accurate solar storm warnings.”
More information from NASA

All Updates, Kids, Resus

Scalp veins

While clearing up after teaching with my bald colleague Dr Phil Hyde yesterday I noticed his bulging scalp veins and this reminded me that we don’t talk about this route much in our Paediatric Emergency Medicine Course.
This prompted me to look up the complications of scalp vein access in neonates and infants, which include:

  • scalp abscess
  • alopecia
  • intracranial abscess
  • thrombophlebitis
  • intracranial venous sinus air embolism
  • scalp necrotising fasciitis

Phil's bulging scalp veins

Suggested ways to decrease the risk of complications include:

  • A vein should not be used for more than 24 h at a time
  • The needle entry point should not be covered
  • The butterfly needle should be immobilized to avoid movements of the needle into the tissue with consequent extravasation of fluid
  • The infusion site should be monitored by regular examination
  • If a swelling or leakage of fluid is noted, the infusion should be discontinued immediately from that site
  • The hair should be properly shaved
  • If the line is required for more than 24 h, a peripheral venous cutdown or central venous line should be considered, after initial resuscitation
  • An alternative route for rehydration (e.g. intraosseous infusion) should be considered initially, rather than risk multiple, unsuccessful attempts at scalp vein cannulation.

Complications of scalp vein infusion in infants
Trop Doct. 2005 Jan;35(1):46-7
Air emboli in the intracranial venous sinuses of neonates
Am J Perinatol. 2002 Jan;19(1):55-8

Resuscitation Medicine from Dr Cliff Reid