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Flashcards in Enviro Emergencies Deck (55)
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1

distribution of elect. injuries?

- young kids: oral contact w/ electric cords and outlets
- adults: construction and electrical workers (90% men)

2

Mech of elect. injury?

- direct effect of electrical current on body tissues: severity depends on voltage, duration, type, current path throughout body, enviro factors
- conversion of elect energy to thermal energy results in deep and superficial burns
- exit wound often larger than entrance site
- as current flows through body, greatest damage is sustained by nerves, blood vessels and muscle

3

Low voltage AV current injury vs high voltage AC and DC injury?

- low voltage AC: will cause muscle tetany, causing injured person to cont grasp source, increasing contact time, tend to cause V fib
- high voltage: cause single violent muscular contraction which tends to throw victim from source, increasing risk of blunt trauma, and blast injuries, tend to cause asystole and resp arrest

4

initial PE of electrical injury?

- primary, secondary surveys, ABCs, C spine immobilization
- IV 2 large bores, fluid repalcement: isotonic crystalloid

5

Neuro PE of electrical injury?

- CNS: neuro impairment occurs in 50% of high voltage injuries, transient LOC, agitation, confusion, coma
- visual disturbances: pupils may be fixed and dilated or asymmetric due to autonomic dysfxn, 50-80% of those struck by lightening have ruptured eardrums
- spinal cord injuries:
fxs, current itself (ascending paralysis, spinal cord syndromes, can be immediate, transient or delayed)
- peripheral nerves: injuries often involve hand touching power source

6

PE for cutaneous wounds for electrical injury?

- burns: entry and exit pts
- look for entrance and exit wounds and degree of burns
- burns can be cleansed and dressed w/ silver suflfadizine
- extremities need careful exam for neurovasc compromise, compartment syndrome

- oral burns:
kids who chew on wires, vasc injury to labial artery can occur, responsible parents can do home monitoring

7

Bone PE in electrical injury?

- bone has highest resistance of any body tissue, generates greatest amt of heat when exposed to electrical current
- areas of greatest destruction are often deep tissue surrounding long bones
- deep electro-thermal tissue injury can result in edme and the development of compartment syndrome

8

Renal PE of electrical injury?

- rhabdo can occur and be complicated by pigment induced renal failure
- hypovolemia due to extravascular extravasation of fluid can lead to prerenal azotemia and acute tubular necrosis

9

Tx of electrical injury? labs?

- trauma: ABCs, c spine
- dysrythmias
- aggressive fluid replacement: isotonic crystalloid fluids, acute hypotension should prompt search for thoracic or intra-abd bleeding secondray to blunt trauma
- labs - lytes, BUN/Cr, CK, serum and urine myoglobin, CBC, EKG
- watch lytes
- wound care
- myoglobinurea: can cause renal failure, amputation may be necessary
- tetanus prophylaxis
- tx seizures
- consult to general surgeon
- kids w/ oral injuries: ENT
- preg women: OB

10

Monitoring electrical burns?

- continuous CV monitoring: arrhythmias occur 15% of time after injury
- needs to be monitored for development of compartment syndrome
- I and O followed, maintain output more than 100 mL/hr as goal, monitor for rhabdo, and renal failure

11

PP of lightning strikes?

- DC current
- can result in:
direct strike
side flash
ground current
step potential (cow is worse off than you)
- extensive tissue damage and renal failure are rare
- immed cardiac arrest result from direct current depolarization of myocardium and can result in systole
- resp arrest from depolarization and paralysis of medullary resp center

12

Minor injuries resulting from lightning strikes?

- stunned pt
- confusion, amnesia
- short term memory problems
- HA
- muscle pain
- parasthesias
- temporary visual or auditory problems
- most minor injuries have gradual improvement, no long term sequelae

13

What would alert you that the pt sustained a lightning injury?

- pt found unconscious or in arrest outside during weather conditions
- pupil dilation or aniscoria may occur
- ruptured tympanic memrbanes or fern like erythematous skin marking

14

Tx of lightning strike injury?

- aggressive resuscitation
- ACLS, CPR
- cardiac monitoring, SAO2, BP
- 2 large bore IVs
- high flow O2
- secondary survey for occult injuries:
cutaneous burns
ocular involvement
auditory involvement
MSK fxs
- labs
- tetanus
- moderate to severe injuries: admite to critical care unit
- minor: admit, closely monitor cardiac and neuro status

15

How common is drowning in US?

- 3rd MC cause of accidental death in US
- 2nd MC in those younger than 45
- leading cause of death in kids under 5 in states where pools and beaches are more accessible

16

RFs for near drowning?

- inability to swim or overestimation of swimming capabilities
- risk taking behavior
- use of EToH or drugs
- inadequate adult supervision
- hypothermia which can lead to rapid exhaustion or cardiac arrhythmias
- concomitant trauma, CVA or MI
- hyperventilation prior to shallow dive

17

PP of drowning?

- after submersion degree of pulm and in particular CNS insult determine ultimate outcome
- drowning begins w/ period of panic:
loss of normal breathing pattern, breath holding, air hunger and struggle to stay above water
- reflex inspiratory efforts occur:
leading to hypoxemia by:
aspiration, reflex laryngospasm

18

Diff b/t dry drowning and wet drowning?

- dry: 10-20% of submersion injuries, caused by laryngospasm, followed by hypoxia and LOC
- wet: aspiration of water, dilution and washout of pulmonary surfactant
- diminished gas transfer
- atelectasis
- ventilation-perfusion mismatch

19

Diff b/t fresh water and salt water drowning?

- fresh:
transient hemodilution, causing blood cells to swell and burst. If large enough vol are aspirated, sig hemolysis is possible
- salt water:
lungs fill w/ salt water which draws blood out of bloodstream and into lungs, build up of Na+ in alveoli stops O2 from reaching blood

20

End organ effects of drowning?

- pulm: fluid aspiration, both salf and fresh water: wash out surfactant, producing noncardiogenic edema and ARDS -S/S: SOB, rales, wheezing
- neuro: hypoxemia, ischemia cause neuronal damage, can produce cerebral edema and elevated ICP, 20% near drowning victims sustain neuro damage limiting fxnl recovery
- CV: arrhythmias 2nd to hypothermia and hypoxemia, sinus brady and fib more common
- acid-base and lytes: metabolic and/or resp acidosis often occurs, sig lyte imbalances don't generally occur except those submerged in unusual media: dead sea

21

Prehosp care of drowning victim?

- asses need for CPR (Pulses may be weak)
- support neck in neutral position
- heimlich manuever or other postural drainage techniques dont help - DON'T delay rescue breathing
- hypothermic pts should be rewarmed

22

Management of drowning victim in ER?

- continue resuscitative efforts
- head and spinal cord injuries should be sought (precip pre near drowning)
- re-warming: blankets, bair hugger, overhead warmers, continue resuscitation unitl pt is at 32-35 C (90-95 F)
- pts w/ GCS 13 or greater: O2, observation for 4-6 hrs, if pulm exam and room air O2 remain normal - d/c, if not better reassess and admit
- GCS less than 13: O2, CXR, labs: ABGs, CBC, CMP, could develop dilutional hyponatremia and have seizures
- PT/PTT UA, CK urine myoglobin, urine drug screen

23

Management of near drowning victim as inpt?

- neuro: major determinants of neuro outcome are:
duration of LOC, neuro state of pt at presentation, goal of management: prevent secondary injury: cerebral edema, hypoxemia, fluid and lytes imbalances, acidosis, seizure activity
- pulm: may need intubation w/ PEEP (ARDS), CXRs should only be done if indicated, bronchospasm is often seen and responds to beta agonists, glucocorticoids or prophylactic abx aren't helpful

24

What are factors assoc w/ a poor prognosis w/ near drowning victim?

- under for more than 10 min
- time to effective BLS: more than 10 min
- resuscitation over 25 min
- hypothermia w/ core temp (less than 33 C or 92F)
- GCS of 5 (comatose)
- younger than 3 yo
- persistent apnea and reqr of CPR in ER
- arterial blood pH less than 7.1
- water temp more than 10C (50F)

25

Define hypothermia?

- core temp less than 35C (95F)
- mild: core temp 90-95F
- mod: 82-90F
- severe: less than 82F
- while mostly seen in cold climates, can develop w/o exposure to extreme enviro conditions

26

What groups are at greatest risk for hypothermia?

- elderly: lose their ability to sense cold
- neonates: large surface to vol ratio
- both groups have limited ability to increase heat production and conserve body heat
- individuals w/ alt sensorium

27

PP of hypothermia?

- heat is generated by cellular metabolism (heart and liver)
- loss by skin and lungs:
evap
radiation
conduction
convection
- heat is preserved by:
periph vasoconstricition, shivering, non-shivering thermogenesis: increase in metabolic rate from thyroid and adrenal glands

28

Presentation of mild hypothermia?

- tachypnea, tachycardia, hyperventilation
- ataxia, dysarthria, impaired judgement
- shivering and cold diuresis

29

Presentation of mod. hypothermia?

- reductions in pulse rate and CO: hypoventilation - a fib, jxnl bradycardia can occur
- CNS depression, hyporeflexia
- decreased renal blood flow and loss of shivering
- paradoxical undressing

30

Presentation of severe hypothermia?

- pulmonary edema
- oliguria
- areflexia
- coma
- hypotension, bradycardia, ventricular arrhythmias, asystole