Initial/Ongoing Management QM 2014. Before we begin; EBR on TBI secondary to ballistic wounds appear...
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Transcript of Initial/Ongoing Management QM 2014. Before we begin; EBR on TBI secondary to ballistic wounds appear...
Before we begin;EBR on TBI secondary to ballistic wounds
appear contradictoryFollowing is based on 1. US, UK, ADF conflict stats 2. Civilian critique of research methods
by Smith et al. 3. Hellenic Military Academy – ‘unique’U.S. Civilian Forensic Experts, Texas,
USAQM 2014
Basic background to BallisticsHi/Low Velocity RoundsBasic Wound Types Upon Presentation (What to look for)
Secondary complications/ ‘Sequelae’Initial /Ongoing Management
QM 2014
KISS
No two situations are the same.However, if the victim is able to give:
1. Distance – approximate (from assailant)2. Round Type – Pistol or longarm (rifle)
Management approach can be pre-emptedBut first the basic differences in weapon
types …
QM 2014
Muzzle velocity is the initial speed of the round as it exits the barrel – particular relevance to close proximity pistol round wounds
Pistol rounds (9mm) have relatively high muzzle velocity, 300 – 350m/s, with exceptional penetrating power at short distances for both soft and hard nose rounds (round = bullet)
Rapid decrease in velocity over short distance (20 - 60 metres)
QM 2014
Any form of deflection, obstacle has significant effect on penetrating power eg. thin, outer panel of car door (mushrooming, tumbling).
Centrefire longarms have higher muzzle velocity, 900 – 950 m/s and higher speeds over longer distances – due to design, rifling – as opposed to pistol rounds.
QM 2014
High Velocity Rounds Bone - Shattering - Non-Reparable - Complex, distal effectsHigh Velocity Rounds Flesh – Depends on round type - Tumbling - Penetrating Tumbling – Extensive, complex Penetrating – Possibility of very little damage as opposed to low velocity
roundsQM 2014
Low Velocity Rounds
Bone - Lower possibility of shattering - Significantly reduced possibility of distal effects, TBI
Flesh - Depends on round type (hollow point) - Likelihood of extensive damage,
used deliberately in CQB, by SF/SO
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Not all research papers recognise the significant difference in round velocity to distance in handgun bullet wounds
‘(In ballistic wounds) the essential condition is the distance to target’ - Alexandropoulou & Panagiotopoulos, 2012
QM 2014
In summary, large calibre longarms and most pistols (9mm +) at close range significantly increase likelihood of TBI from pressure waves
Pistols at ‘most’ distances cause significant damage to flesh
Victim may be ‘lucky’ with high velocity flesh wound from a longarm*
QM 2014
In addition to the penetration medium (bone, flesh or combination) three other factors affect wound type
Permanent cavity destroyed upon entry – missile morphology and velocity
Fragmentation – missile or bone – not all wounds
AND …. QM 2014
Temporary cavity (5 – 12cm radius) – extension of permanent cavity by kinetic energy transported in tissues by missile
– Serious implications for surgery within the first 3 hour window in assessing tissue to be excised.
Vasospasm – approx. 3 hrs. from hi-vel. wound – colour, bleeding, contractility and consistency parameters for surgery assessment.
3 hrs. vasospasm/constriction followed by hyperaemia*
QM 2014
TBI from a distal injury not to be confused with injuries from the temporary cavity.
‘Injuries from the temporary cavity are more common in closer proximity to less elastic (brain, liver spleen), fluid filled and dense tissue. Elastic tissue (skeletal muscle) and lower density (lung) are less affected.’
Snow and Bozeman, 2010
QM 2014
Pressure Wave induced TBI‘ … instantaneous perturbation of dentate inter-neuronal networks by a transient pressure wave-delivered to the neocortex (2)’Results from combined human (DVBIC) USA), animal and simulated compound researchNeuron loss in the hippocampus – Hilus of the dentate gyrus due to pressure waveCells are large and not tightly packed
QM 2014
TBI - Damage to the hippocampus, then damage to the hypothalamus if pressure wave strong enough
BBB - appears to open periodically within first 24 hours of TBI – allowing passage of proteins and substances otherwise excluded from the brain . Alterations to brain osmolarity and oedema formation
QM 2014
Over expression of Aquaporin channels – permit movement of water into lateral ventricles > exacerbate cerebral oedema
Glutamate (excitatory neurotransmitter) causes influx of Sodium and calcium > hi intra cellular concentrations after TBI.
QM 2014
Excess Calcium initially buffered by sarcoplasmic reticulum, eventually saturated, excess taken up by mitochondria acting as ‘calcium sink’ under stress situations
With other stimuli, mitochondrial permeability transition pore forms > depolarization, swell with calcium intake, leak due to intra-organelle oedema and ATP production becomes deficient. In a highly metabolically active cell > energy failure. Cytochrome C is also released which promotes apoptosis.
High IC Ca+ attacks cytoskeleton, cytosolic proteins and DNA structures
QM 2014
A – Airway – C Spine protection/Haemorrhage controlB – BreathingC – Circulation/CompressionsD – Defib./Disability Observe for: Ecchymosis (do not confuse w/bruising) Paralysis of face muscles Declination of eyes to one side CSF liquid from ear, nose or wound One short, lucid interval followed by reduced LOC, headache, nausea and vomiting
QM 2014
Ideal state – Eu to moderate hypervolaemia
Isotonic and hypertonic fluids – essential early intervention to maintain cerebral perfusion. To be managed with delayed hyperaemia that can lead to cerebral oedema and inc. ICP
NS not Lactated Ringers/Hartmann's
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Fluids do not replace O2 carrying capacity. At some point blood will have to be given in severe cases.
ICP to be maintained at < 20mmHg and CPP at >60mmHg (hospital based monitoring)
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O2 – caution excess
Up to 50% pre-hospital admissions, inadvertent hyperventilation leads to pCO2 < 33mmHg > incr. mortality in patients with TBI.
Hypocapnea - Implications for vasoconstriction , reduced cerebral blood flow and regional ischemia.
QM 2014
O2 – Caution excess/under use
Insufficient O2 - Common problems associated with TBI are changing LOCs and transient periods of hypoxia. Hypoxic periods > bradycardia in TBI patients and exacerbate secondary brain injury
QM 2014
IIT background Lantus/Levemir, medium short acting if time, circumstances permit
Glucose Constant BGL monitoringConservative control, both hyper and
hypoglycaemia can aggravate primary brain injury
Insulin – assess short, medium, long actingSerious implications for brain energy‘Meta-analysis’ – does not support IIT
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Hypothermia
Randomized trials at 37 & 30 Degrees CelsiusReduce glutamate release and free radical
production after TBI. Essential to maintain therapeutic levels for CNS signalling. Excess glutamate responsible for neurological dysfunction associated with TBI.
Glutamate levels increase by over 250% in the dentate gyrus alone in mild brain injury
QM 2014
Magnesium Salts – with mannitol to improve brain bio-availability - Mg down regulates aquaporin 4 reducing cellular oedema*
MgSO4 induces smooth muscle relaxation, principally in the airway
Clinical trials stating that Mg was of no benefit – pts required intracranial brain surgery within 8 hrs or had the GCS of a rocking chair
Cyclosporine A – inhibit opening of the mitochondrial permeability transition pore.
QM 2014
DVT/PE ProphylaxisCompression stockingsHold LMW heparin/low dose unfractionated
heparin until 48 – 72 hours after admission – possible risk for expansion of intracranial haemorrhage
Stress Ulcer Prophylaxis (Severe TBI)PPI infusion – most effective (Pantoprazole)H2 blockers – block histamine, reduce enteric acid
(location)Sucralfate – duodenal ulcers – specific to stress
ulcer proph.Early enteral feeding
QM 2014
Avoid:
Calcium channel blockers Reduce systemic blood pressure and CPP
Corticosteroids Bleeding, hyperglycaemia, increase in
cerebral metabolic rate and fluid retention
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Principally hospital based
Prevent sequelae – ischemia, haematoma, vasospasm
Pulse OximetryIntraparenchymal Brain Catheters increasing in
use due to ease, versatility and ‘short learning curve’ (ICU)
ICP and PtiO2/PbrO2/PBTO2 determine treatment
QM 2014
To determine benefits of MgCl2 over MgSO4 – possibility of reduced toxicity with MgCl2
Possible benefits of Substance P inhibitors in TBI patients
Oestrogen and Progesterone in TBI management Mg in combination with Tirilazad – nonglucocorticoid neuroprotectant
to reduce vasospasm B2 – Antioxidant, NS function Dexanabinol – anticonvulsant, neuroprotectant
QM 2014
Tape paper bags to the hands of GSW victims until police swabs completed
Place any cut/discarded clothing in paper, not plastic bags due to condensation and damage to potential evidence.
QM 2014
Alexandropoulou, C., & Panagiotopoulos, E. (2010). Wound Ballistics: Analysis of Blunt and Penetrating Trauma Mechanisms. Health Science Journal, 4(4), 225-236.
Courtney, A., & Courtney, M. (2007). Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities. Brain Injury, 21(7), 657-662
Davis, D., Fakhry, S., Wang, H., Bulger, E., Domeier, R., Trask, A., & ... Robinson, L. (2007). Paramedic rapid sequence intubation for severe traumatic brain injury: perspectives from an expert panel. Prehospital Emergency Care, 11(1), 1-8.
Dr. Vincent J. M. Di Maio, Chief Medical Examiner and Director of the Regional Crime Laboratory, County of Bexar, San Antonio, Texas (from his Gunshot Wounds, CRC Press, Boca Raton, FL, 1985).
Sen, A, & Gulati, P. (2010). Use of Magnesium in Traumatic Brain Injury. Neurotherapeutics: The Journal of the American Society for Experimental NeuroTherapeutics.
Snow, A., & Bozeman, J. (2010). Role implications for nurses caring for gunshot wound victims. Critical Care Nursing Quarterly, 33(3), 259-264
Wallace, D. (2009). Improvised explosive devices and traumatic brain injury: the military experience in Iraq and Afghanistan. Australasian Psychiatry, 17(3), 218-224.
QM 2014
DVT Prophylaxishttp://www.sjtrem.com/content/20/1/12 IPBC;http://www.slideshare.net/pgpapanikolaou/08
3009papanikolaoupanagiotis439744
The Dentate Gyrus;http://www.jle.com/en/revues/bio_rech/mrh/e-
docs/00/04/11/9B/article.phtml
QM 2014