Episode 4: Chemical incidents

01/06/16 • 42 min

https://phemcast.co.uk/wp-content/uploads/2016/01/chemical-incidents.mp3

We hope you enjoyed this PHEMCast. Please feedback your comments via the blog, twitter or email us on [email protected].

The NARU video we mention in the podcast can be accessed here:

http://naru.org.uk/videos/ior-nhs/

And the paper we discuss is:

Chilcott RP. Managing mass casualties and decontamination. Environmental International. 2014; 72: 37-45.

This is the Step 1,2,3 tool described:

For more information on the toxidromes associated with various chemicals, biological agents and radiation sources have a look at this document (admittedly it’s a few years old but the content is still good, especially the flow chart which is pasted below):

http://www.gov.uk/government/uploads/system/uploads/attachment_data/file/340709/Chemical_biological_radiological_and_nuclear_incidents_management.pdf

What is an anti-muscarinic chemical?

Anti-muscarinic = blocking the muscarinic receptors, ie blocking the effect of acetylcholine, hence also called anti-cholinergic. Impacts on parasympathetic stimulation. Antimuscarinic effects include dilated pupils (leading to blurred vision), reduced secretion of saliva (hence dry mouth), sweat and digestive juices. Relaxation of smooth muscle causing urinary retention, ileus. Also tachycardia, confusion progressing to delirum/coma.
Nerve agents inhibit anticholinesterase therefore there is an excess of acetylcholine resulting in opposite features: diarrhoea, urination, miosis, increased bronchial secretions, bronchoconstriction, vomiting, lacrimation, salivation.

Always ahead of the curve... St Emlyns have recently published a blog post on this very topic! It’s great, so have a read:

http://stemlynsblog.org/cbrn-an-introduction/

Further Reading

Monteith RG. Pearce LDR. Self-care Decontamination within a Chemical Exposure Mass-casualty Incident. Prehospital and Disaster Medicine. 2015; 30: 288-296.
http://chemm.nlm.nih.gov/mmghome.htm
Centers for Disease Control and Prevention. Chemical Suicides in Automobiles – Six States, 2006-2010. JAMA. 2001; 306(16): 1751-1753.
http://www.msdmanuals.com/en-gb/professional/injuries;-poisoning/poisoning/general-principles-of-poisoning#v1118045
https://www.england.nhs.uk/wp-content/uploads/2015/04/eprr-chemical-incidents.pdf
JRCALC http://www2.warwick.ac.uk/fac/med/research/hsri/emergencycare/prehospitalcare/jrcalcstakeholderwebsite/guidelines/chemical_biological_radiological_and_nuclear_incidents_2006.pdf

How to cite this podcast:

Nutbeam T, Bosanko C. Chemical Incidents. PHEMCAST. 2016 [cite Date Accessed]. Available from: http://www.phemcast.co.uk

https://phemcast.co.uk/wp-content/uploads/2016/01/chemical-incidents.mp3

We hope you enjoyed this PHEMCast. Please feedback your comments via the blog, twitter or email us on [email protected].

The NARU video we mention in the podcast can be accessed here:

http://naru.org.uk/videos/ior-nhs/

And the paper we discuss is:

Chilcott RP. Managing mass casualties and decontamination. Environmental International. 2014; 72: 37-45.

This is the Step 1,2,3 tool described:

http://www.gov.uk/government/uploads/system/uploads/attachment_data/file/340709/Chemical_biological_radiological_and_nuclear_incidents_management.pdf

What is an anti-muscarinic chemical?

Anti-muscarinic = blocking the muscarinic receptors, ie blocking the effect of acetylcholine, hence also called anti-cholinergic. Impacts on parasympathetic stimulation. Antimuscarinic effects include dilated pupils (leading to blurred vision), reduced secretion of saliva (hence dry mouth), sweat and digestive juices. Relaxation of smooth muscle causing urinary retention, ileus. Also tachycardia, confusion progressing to delirum/coma.
Nerve agents inhibit anticholinesterase therefore there is an excess of acetylcholine resulting in opposite features: diarrhoea, urination, miosis, increased bronchial secretions, bronchoconstriction, vomiting, lacrimation, salivation.

Always ahead of the curve... St Emlyns have recently published a blog post on this very topic! It’s great, so have a read:

http://stemlynsblog.org/cbrn-an-introduction/

Previous Episode

Episode 3: Hyperoxia

https://phemcast.co.uk/wp-content/uploads/2015/12/episode-3-hyperoxia.mp3

Hello and welcome to our next episode – we hope you enjoy it. This episode concentrates on hyperoxia – the delivery of lots (often too much) oxygen and the harms it may cause our patients. We both had colds – many apologies for the blocked noses and many sniffs!

We hope you find it useful.

To follow: Dr Matt Thomas from the Great Western Air Ambulance discussing his groups work around reducing hyperoxia post-rosc.

Next Episode

Episode 5: Amputation

https://phemcast.co.uk/wp-content/uploads/2016/02/amputation.mp3

Welcome to PHEMCAST episode 5: Amputation

One of the things we never want to have to do, but need to be prepared for. Have a listen, consider your kit, your top-cover arrangements, and when and how you may need to get this done.

This podcast covers, which patients to consider, how to do it and discussion around consent, capacity and top-cover arrangements.

This podcast features interviews with Professor Sir Keith Porter and Caroline Leech, which we hope you will enjoy.

Which patients / scenarios:

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.

Which kit:

CAT x 2
Scalpel
Gigli saw (and spare)
Arterial forceps x 4
Tuff Cut scissors
Appropriate dressing (e.g. Israeli combat bandage)

Preparation:

Sedation or anaesthesia
Brief team
Plan next phase

Stages of amputation process:

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.

(consider IV antibiotics if can be delivered as concurrent activity)

Please contribute to the blog below – specifically around top cover arrangements, decision making and individual competency around this procedure.

References:

Porter KM. Prehospital amputation. Emerg Med J. 2010 Dec 1;27(12):940–2.

Reid C, Clancy M. Life, limb and sight-saving procedures–the challenge of competence in the face of rarity. Emerg Med J. 2013 Feb 1;30(2):89–90. .

Porter K. Ketamine in prehospital care. Emerg Med J. 2004 May 1;21(3):351–

Brodie S, Hodgetts TJ, Ollerton J, McLeod J, Lambert P, Mahoney P. Tourniquet use in combat trauma: UK military experience. J R Army Med Corps. 2007 Dec 1;153(4):310–3.

Akporehwe NA, Wilkinson PR, Quibell R, Akporehwe KA. Ketamine: a misunderstood analgesic? BMJ. 2006 Jun 24;332(7556):1466.

McNicholas MJ, Robinson SJ, Polyzois I, Dunbar I, Payne AP, Forrest M. ‘Time critical’ rapid amputation using fire service hydraulic cutting equipment. Injury. 2011; 42: 1333-1335.