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Flashcards in Enviro Emergencies Deck (55)
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distribution of elect. injuries?

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


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


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


initial PE of electrical injury?

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


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


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


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


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


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


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


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


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


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


Tx of lightning strike injury?

- aggressive resuscitation
- 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


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


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


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


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


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


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


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


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


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


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)


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


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


PP of hypothermia?

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


Presentation of mild hypothermia?

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


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


Presentation of severe hypothermia?

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


Dx of hypothermia?

- must use low reading thermometer
- labs to ID potential complications:
coag studies
EKG: elevation of J pt: J or osborne wave


Management of hypothermia?

- ABCs
- initiation of rewarming:
*passive external and *active external: combo of blankets, radiant heat, warm baths or forced warm air, risk is core temp afterdrop - occurs when trunk and extremities are warmed simult - so warm trunk 1st and minimize use of periph muscles
*active internal rewarming: can be used alone or w/ active external rewarming, pleural and peritoneal irrigation w/ warm saline, hemodialysis and cardiopulm bypass, warm humidified O2, warm IV fluids and bladder or GI irrigation w/ warm saline


Tx arrhythmias in hypothermia?

- hypothermic heart is very sensitive to movement and rough handling of pt may precipitate arrhythmias
- A fib and flutter usually resolve w/ rewarming
- management of V fib and asystole can be difficult - they may be refractory to therapy until pt has been rewarmed (core temp 86-90F)


PP of frostbite?

- freezing of tissue: disease of morbidity not mortality
tissue destruction due to:
- immed cold induced cell death
- more gradual development of localized inflammation and tissue ischemia - made worse in setting of thawing followed by refreezing


Classification of frostbite?

-1st degree: central area of pallor and anesthesia of skin surrounded by edema (superficial)
- 2nd: blisters form containing clear or milky fluid surrounded by edema/erythema w/in 24 hrs (superficial)
- 3rd: injury deeper than 2nd degree, blisters are hemorrhagic, progressing to black eschar over several weeks (deep)
- 4th: extends to muscle and bone, involves complete tissue necrosis (deep)


Simpler classification of frost bite?

- superficial corresponds to 1 and 2nd degree
- deep: 3-4th degree


Presentation of frostbite?

- pt c/o numbness, clumsiness of affected area
- skin may be insensate, white or grayish yellow in color and hard or waxy to touch
- bullae may be present
- cases of delayed presentation eschars or sign of tissue necrosis may be present


Dx of frostbite?

- made clinically
- dx studies helpful to determine existence of comorbidities and extent of injury:
Technetium-99 scintography used to predict long term viability of affected tissue
- goal is to allow earlier debridement or amputation of dead or dying areas while leaving viable tissue intact


Prehosp tx of frostbite?

- remove wet clothes
- avoid walking on frostbitten feet
- don't rewarm if there is possibility of refreezing
- don't rub frostbitten areas
- avoid use of stoves or fires to rewarm


What prog factors should you determine w/ frostbite?

- temp and wind velocity
- how long was extremity frozen
- if thawed, did refreezing occur
- was there any self tx: rubbing w/ aloe vera cream or ibuprofen
- recreational drugs or alcohol involved
- any predisposing medical conditions


Tx in hosp of frostbite?

- rapid rewarming:
waterbath heated to 40-42 C
- dry heat diff to regulate
- thawing usually completed in 15-30 min
- application of dressing, elevation, splinting
- tetanus proph
- topical aloe and ibuprofen
- in pts at high risk for life alt amputation: tPA
- surgical consultation: may reqr long term wound care, daily hydrotherapy, repeatd tissue debridement, escharotomy and poss delayed amputation


Managing blisters in frostbite pts?

- drain, debride, bandage large nonhemorrhagic bullae that interfere w/ movement
- hemorrhagic bullae of comparable size and location are drained by aspiration, but not debrided
- minor bullae should be left intact


Complications of frost bite?

- short term: infection, gangrene, autoamputation
- long term: hypersensitivity to cold w/ increased risk for developing frostbite again, chronic parasthesias, decreased sensation to touch when hands are involved


2 types of heat exhaustion?

- water depletion: inadequate fluid replacement by individuals working in hot enviro - can progress to heat stroke (hypovolemia)
- salt depletion: large volumes of thermal sweat are replaced w/ water w/ too little salt: hyponatremia, hypochloremia
- most cases are mixed


S/S of heat exhaustion?

- reflects sig vol depletion
- non-specific sxs:
weakness, malaise, fatigue, HA, lightheadedness, dizzines, N/V
- clinical manifestations: hypotension, tachycardia, tachypnea, diaphoresis, syncope


Tx of heat exhaustion?

- cool enviro
- vol and lyte replacement
- mild cases: oral replacement
- moderate cases: 1-2 L of NS, guided by serum lytes


What is heat stroke?

- life threatening emergency that occurs when homeostatic thermoregulatory mechanisms fair
- elevation of body temp over 40.5C (105F)
- w/ elevation of temp, cell damage occurs: tissue damage is affected by:
body temp
exposure time
work load
tissue perfusion


PP of heat stroke?

- CNS dysfxn w/ occurrence of cerebral edema is common:
ataxia, irritability, confusion, bizarre behavior, combativeness
- greatly increases skin blood flow: fxnl hypovolemia compensated by vasoconstriction of splanchnic and renal vasculature
- if severe heat stress cont: splanchnic vasoconstriction will fail, heated blood increases ICP, decreases mean arterial pressure


Dx of heatstroke?

- exposure to heat stress, endogenous or exogenous
- signs of severe CNS dysfxn
- core temp usually above 104.9F (40.5C)
- dry, hot skin, but sweating may persist
- marked elevation of liver transaminases


How can heatstroke kill?

- about 10% of cases are fatal
- vascular sock: reduces blood flow to brain, leads to nervous system malfxn
- irregular pulse: arrhythmia - Heart atatck
- kidney failure
- blood clots start to form affecting vessels throughout body


Tx of heatstroke?

- ABCs: O2, cardiac monitoring, pulse Ox
- primary survey
- cooling is immediate goal: once pt arrives at hop - clothes should be removed nad rectal thermostat probe inserted for cont temp monitoring
- cooling tech:
evap cooling
cold water immersion
ice packing: neck, groin, axillae
cold gastric lavage: NG tube
cold peritoneal lavage : also used in some cases of AMI and ischemic CVA to mitigate myocardial and cerebral tissue damage


What is evaporative cooling?

- positioning fans close to completely undressed pt then spraying them w/ water
- disadvantages:
shivering, inability of cardiac electrodes to adhere to skin


What is immersion cooling?

place undressed pt in tub of ice water deep enough to cover trunk and extremities


WHen should cooling efforts be d/c?

- when rectal temp reaches 40C (104F)
- continued cooling below this may lead to hypothermia


Why is airway control essential in heat stroke? Why should fluid admin be done carefully?

- seizures and aspiration are common: need airway control
- hypotension is common but fluid admin needs to be done carefully as some pts can develop pulm edema
- tachyarrhythmias often occur and usually resolve w/ cooling