Some persist in thinking and teaching that the ‘vasopressor’ noradrenaline (norepinephrine) increases mean arterial pressure (MAP) simply by increasing systemic vascular resistance, leading to concerns that it may increase blood pressure at the expense of tissue perfusion. This assertion is contested by many, who now have further support from this study.
In 16 patients with septic shock, various measures of peripheral perfusion were recorded while the dose of noradrenaline was increased to achieve target MAPs. The use of noradrenaline to achieve incremental targets for MAP was associated with increases in global oxygen delivery, cutaneous microvascular flow, and tissue oxygenation in patients with established septic shock; there were no associated changes in the preexisting abnormalities of sublingual microvascular flow. The authors state that these findings suggest that in patients with septic shock, improvements in global hemodynamics and tissue oxygen delivery can be achieved with noradrenaline, without exacerbating microcirculatory flow abnormalities.
The effect of increasing doses of norepinephrine on tissue oxygenation and microvascular flow in patients with septic shock
Crit Care Med. 2009 Jun;37(6):1961-6
Category Archives: All Updates
MAU faster than wards, but slower than ED
In many UK hospitals patients referred to hospital by their family doctors may bypass the emergency department (ED) and be admitted straight to admissions units, where additional staff duplicate the assessment and investigation that would have been done in the ED. The ED continues to see self-presenting and emergency ambulance cases as well as patients who ‘spill over’ when the admission units are full.
The effect of the introduction of a Medical Admissions Unit (MAU) on times to key interventions for four acute medical conditions was assessed. Interventions were delivered significantly faster in the ED than on the MAU, which in turn provided specific interventions faster than the general medical wards.
The authors rightly conclude that acute admissions should be assessed in a dedicated unit fit for purpose. It would appear from their data that if the purpose is timely intervention, then the ED is the most fit.
Improvement in time to treatment following establishment of a dedicated medical admissions unit
Emerg Med J. 2009 Dec;26(12):878-80
No benefit from drugs in pre-hospital cardiac arrest
A Norwegian randomised controlled trial over five years compared out-of-hospital nontraumatic cardiac arrest outcomes between ACLS protocols with and without access to intravenous drugs (epinephrine/adrenaline, atropine, amiodarone).
Patients randomised to the drug group had a higher rate of hospital admission with return of spontaneous circulation, but there was no significant difference in survival to discharge, survival with favourable neurological outcome, or one year survival.
Intravenous Drug Administration During Out-of-Hospital Cardiac Arrest
JAMA. 2009 Nov 25;302(20):2222-9
Abdominal distension as a sign of tension pneumothorax
In both adults and children, abdominal distension (which may be massive in children) may be a sign of tension pneumothorax.
Crisis management during anaesthesia: pneumothorax
Qual Saf Health Care. 2005 June; 14(3): e18
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Characteristic ECG signs of LAD occlusion without ST elevation
In a single centre observational study over 10 years of patients undergoing acute PCI of the left anterior descending (LAD) artery, 35 of 1890 (2%) had a distinct non-ST elevation ECG pattern.
The ECG showed ST-segment depression at the J-point of at least 1 mm in the precordial leads with upsloping ST-segments continuing into tall, symmetrical T-waves. Patients also showed a mean J-point elevation of approximately 0.5 mm in lead aVR.
This novel ECG pattern resolved after reperfusion in all included patients.
The authors caution that these electrocardiographic changes may be missed or misdiagnosed as reversible ischaemia, which might substantially delay the transportation to a PCI centre or the start of reperfusion therapy
The authors conclude: “It is important for cardiologists and emergency care physicians to recognise this distinct ECG pattern, so they can triage such patients for immediate reperfusion therapy.”
Persistent precordial “hyperacute” T-waves signify proximal left anterior descending artery occlusion
Heart. 2009 Oct;95(20):1701-6
ACEP pneumonia statement
The American College of Emergency Physicians has conducted an evidence review and issued a policy regarding two critical issues surrounding ED management of pneumonia: whether blood cultures should be taken and in what time frame antibiotics should be administered.
The full document is available from the ACEP website:
Clinical Policy: Critical Issues in the Management of Adult Patients Presenting to the Emergency Department With Community-Acquired Pneumonia
Is cervical spine protection always necessary following penetrating neck injury?
This short cut review in the Best Bets format attempted to answer the question: “is cervical spine protection always necessary following penetrating neck injury?”
From the available evidence they draw the following conclusions:
- In stab wounds to the neck (with or without neurological deficit) an unstable spinal injury is very unlikely and c-spine immobilisation is not needed
- In gunshot wounds the value of cspine immobilisation is limited: for gunshot wounds without neurological deficit no immobilisation is required, while in cases of gunshot wounds with neurological deficit, or where the diagnosis cannot be made (ie, altered mental status), a collar or sandbag is advised once ABCs are stable, with close observation and intermittent removal to inspect and reassess.
- In the rare event of penetrating injury with combined blunt force trauma, a collar or sandbag is advised if possible, once ABCs are stable, with intermittent removal to reassess.
Emerg Med J. 2009 Dec;26(12):883-7
Full text at BestBets.org
New College of Emergency Medicine Guidelines
New guidelines from the (UK) College of Emergency Medicine are available at http://www.collemergencymed.ac.uk by going to he Clinical Effectiveness Committee page.
Can venous blood gases replace arterial gases?
A comprehensive summary of the literature presented by Professor Anne-Maree Kelly in June 2009 at 4ème SYMPOSIUM INTERNATIONAL BLOOD GASES AND CRITICAL CARE TESTING in France can be viewed on her presentation slides at the link below.
She summarises:
- pH – Close enough agreement for clinical purposes in DKA, isolated metabolic disease; more work needed in shock, mixed disease
- Bicarbonate – Close enough agreement for clinical purposes in most cases; more work needed in shock, mixed disease, calculated vs measured gap
- pCO2 – NOT enough agreement for clinical purposes; potential as a screening test
- Potassium – Insufficient agreement between serum and BG values for clinical purposes
- Base excess – Insufficient data
Can venous blood gas analysis replace arterial in emergency and critical care?
Spinal imaging and immobilisation may be unnecessary in many GSW patients
A retrospective review of 4204 patients sustaining gunshot wounds (GSW) to the head, neck or torso examined the incidence of spinal cord injury and bony spinal column injury required operative spinal intervention. None of the patients demonstrated spinal instability requiring operative intervention, and only 2/327 (0.6%) required any form of operative intervention for decompression. The authors concluded that spinal instability following GSW with spine injury is very rare, and that routine spinal imaging and immobilisation is unwarranted in examinable patients without symptoms consistent with spinal injury following GSW to the head, neck or torso.
The role of routine spinal imaging and immobilisation in asymptomatic patients after gunshot wounds
Injury. 2009 Aug;40(8):860-3