Enviro Emergencies Flashcards
1
Q
distribution of elect. injuries?
A
- young kids: oral contact w/ electric cords and outlets
- adults: construction and electrical workers (90% men)
2
Q
Mech of elect. injury?
A
- 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
Q
Low voltage AV current injury vs high voltage AC and DC injury?
A
- 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
Q
initial PE of electrical injury?
A
- primary, secondary surveys, ABCs, C spine immobilization
- IV 2 large bores, fluid repalcement: isotonic crystalloid
5
Q
Neuro PE of electrical injury?
A
- 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
Q
PE for cutaneous wounds for electrical injury?
A
- 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
Q
Bone PE in electrical injury?
A
- 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
Q
Renal PE of electrical injury?
A
- 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
Q
Tx of electrical injury? labs?
A
- 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
Q
Monitoring electrical burns?
A
- 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
Q
PP of lightning strikes?
A
- 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
Q
Minor injuries resulting from lightning strikes?
A
- 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
Q
What would alert you that the pt sustained a lightning injury?
A
- 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
Q
Tx of lightning strike injury?
A
- 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
Q
How common is drowning in US?
A
- 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
Q
RFs for near drowning?
A
- 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
Q
PP of drowning?
A
- 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
Q
Diff b/t dry drowning and wet drowning?
A
- 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
Q
Diff b/t fresh water and salt water drowning?
A
- 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
Q
End organ effects of drowning?
A
- 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
Q
Prehosp care of drowning victim?
A
- 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
Q
Management of drowning victim in ER?
A
- 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
Q
Management of near drowning victim as inpt?
A
- 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
Q
What are factors assoc w/ a poor prognosis w/ near drowning victim?
A
- 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
Q
Define hypothermia?
A
- 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
Q
What groups are at greatest risk for hypothermia?
A
- 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
Q
PP of hypothermia?
A
- 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
Q
Presentation of mild hypothermia?
A
- tachypnea, tachycardia, hyperventilation
- ataxia, dysarthria, impaired judgement
- shivering and cold diuresis
29
Q
Presentation of mod. hypothermia?
A
- 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
Q
Presentation of severe hypothermia?
A
- pulmonary edema
- oliguria
- areflexia
- coma
- hypotension, bradycardia, ventricular arrhythmias, asystole
31
Q
Dx of hypothermia?
A
- must use low reading thermometer
- labs to ID potential complications:
lytes
hematocrit
coag studies
ABGs
EKG: elevation of J pt: J or osborne wave
32
Q
Management of hypothermia?
A
- 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
33
Q
Tx arrhythmias in hypothermia?
A
- 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)
34
Q
PP of frostbite?
A
- 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
35
Q
Classification of frostbite?
A
- 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)
36
Q
Simpler classification of frost bite?
A
- superficial corresponds to 1 and 2nd degree
- deep: 3-4th degree
37
Q
Presentation of frostbite?
A
- 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
38
Q
Dx of frostbite?
A
- 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
39
Q
Prehosp tx of frostbite?
A
- 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
40
Q
What prog factors should you determine w/ frostbite?
A
- 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
41
Q
Tx in hosp of frostbite?
A
- 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
42
Q
Managing blisters in frostbite pts?
A
- 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
43
Q
Complications of frost bite?
A
- 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
44
Q
2 types of heat exhaustion?
A
- 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
45
Q
S/S of heat exhaustion?
A
- reflects sig vol depletion
- non-specific sxs:
weakness, malaise, fatigue, HA, lightheadedness, dizzines, N/V - clinical manifestations: hypotension, tachycardia, tachypnea, diaphoresis, syncope
46
Q
Tx of heat exhaustion?
A
- cool enviro
- vol and lyte replacement
- mild cases: oral replacement
- moderate cases: 1-2 L of NS, guided by serum lytes
47
Q
What is heat stroke?
A
- 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
48
Q
PP of heat stroke?
A
- 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
49
Q
Dx of heatstroke?
A
- 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
50
Q
How can heatstroke kill?
A
- 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
51
Q
Tx of heatstroke?
A
- 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
52
Q
What is evaporative cooling?
A
- positioning fans close to completely undressed pt then spraying them w/ water
- disadvantages:
shivering, inability of cardiac electrodes to adhere to skin
53
Q
What is immersion cooling?
A
place undressed pt in tub of ice water deep enough to cover trunk and extremities
54
Q
WHen should cooling efforts be d/c?
A
- when rectal temp reaches 40C (104F)
- continued cooling below this may lead to hypothermia
55
Q
Why is airway control essential in heat stroke? Why should fluid admin be done carefully?
A
- 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
