KC Environment Flashcards
*What are the definitions of mild, moderate, severe and profound hypothermia?
- Mild: 33-35 degrees Celsius
- Moderate: 29-32 degrees Celsius
- Severe: 22-28 degrees Celsius
- Profound: 20 degrees and lower
*What are the indications for active external rewarming?
Previously healthy patients with acute hypothermia are optimal candidates for AER
*What are the indications for active core rewarming?
- Moderate or severe hypothermia (temperature <= 32 degrees Celsius)
- Cardiovascular instability
- Inadequate rate of rewarming or failure to rewarm
- Endocrinologic insufficiency (e.g. adrenal insufficiency, DKA, hypopit)
- Traumatic or toxicological peripheral vasodilation (e.g. spinal cord transection)
- Secondary hypothermia impairing thermoregulation
*Temperature doesn’t rise with interventions, why not?
(1) Adrenal insufficiency - give methylprednisolone or hydrocortisone.
(2) Myxedema - levothyroxine
(3) Sepsis - Ab
(4) Hypoglycemia - D50
*5 methods of heat loss
- Radiation
- Conduction
- Convection
- Respiration
- Evaporation
*5 methods of noninvasive rewarming
Rewarming options include plumbed garments that circulate warm fluids, hot water bottles, heating pads, forced air warming systems, and radiant sources.
*2 methods of invasive rewarming
Airway rewarming
Peritoneal dialysis
Heated irrigation
Endovascular rewarming
ECMO rewarming
*4 causes of failure to rewarm and interventions for each
(1) Adrenal insufficiency - give methylprednisolone or hydrocortisone.
(2) Myxedema - levothyroxine
(3) Sepsis - Ab
(4) Hypoglycemia - D50
*In the setting of hypothermia, please provide the temperature at which the following physiologic changes occur
1 Ataxia and apathy develop
2 Extinguishing of shivering thermogenesis
3 At this temperature the body assumes a poikilothermic state
4 Temperature above which ACLS medications are indicated for arrested patient
5 Onset of VF susceptibility; 50% decrease in 02 consumption
1 Ataxia and apathy develop -33
2 Extinguishing of shivering thermogenesis -31
3 At this temperature the body assumes a poikilothermic state -30
4 Temperature above which ACLS medications are indicated for arrested patient - 30
5 Onset of VF susceptibility; 50% decrease in 02 consumption - 28
*6 EKG changes in hypothermia
- Osborne waves
- Sinus Bradycardia
- Prolonged QT, PR, QRS
- VF
- Asystole
- Atrial fibrillation
*What effect does hypothermia have on the oxy-Hb dissociation curve
Left shift
*The ABG machine heats the blood to 37 C.
i) The result of the PO2 will appear higher/lower
ii) The result of the pH will appear higher/lower
i) Increases the partial pressure of blood gases – higher P02 and higher PC02
ii) Lower ph
*4 mechanisms of heat loss in the treatment of hyperthermia and list 1 example for each
- Conduction - cool water bath
- Convection - fan at bedside
- Radiation - take off clothes (facilitate radiation)
- Evaporation – spray with normothermic mist
*3 immediate treatments for core temp <28
Active rewarming, options listed above
2 end points for termination of resusciation of *hypothermic patient
Temp > 32 with asystole on monitor and no cardiac activity on US
Valid DNR order
obvious signs of irreversible death - non compressive chest, decapitation
conditions unsafe for rescuers
avalanche burial 35 min or +, airway packed with snow
serum K+> 12
*Risk factors for Hypothermia in elderly patients
-Poly-pharmacy / medications
-Dementia/ cognitive deficits
-Poor (low socioeconomic)
-Endocrine disease
-Malnourished
-Social isolation
-Age (impaired thermoregulation)
*What 3 things can be done in a pre-hospital environment for this patient specifically to lower core temperature?
Ice water immersion
Removal from hot environment (move to ac, shade…)
Fan
Remove clothes
ICe packs.
*4 mechanisms of heat loss in the treatment of hyperthermia and list 1 example for each
-Conduction - cool water bath
-Convection - fan at bedside
-Radiation - take off clothes (facilitate radiation)
-Evaporation – spray with normothermic mist
*3 findings that differentiate heat stroke and heat exhaustion
Altered mental status
Core temperature >40.5 (loss of compensation)
End-organ damage
*6 pharmacologic causes of this presentation (different classes) (Hot and crazy)
- Anticholinergic
- Sympathomimetics
- EtOH withdrawal
- Benzo withdrawal
- ASA/clopidogrel
- NMS
- MH
*What are 3 management points for heat stroke
Cooling
Correct electrolyte imbalance/fluid deficit
Control seizure (benzo),
Limit shivering (paralysis and intubation PRN).
*List two early physiologic responses to heat stress
- earlier onset of sweating (ie at lower core temp)
- lowered sweat Na
- increased sweat V
- Expanded / increased plasma V
- Lower HR with higher stroke V
- earlier release of aldosterone (and lower amounts)
*One lab result most characteristic of heat stroke
Transaminitis
*Two ways of quickly cooling patients
- Evaporative cooling using fans and skin wetting (spraying)
- Ice water immersion (conduction)
*8 clinical features of heatstroke
• Exposure to heat stress, endogenous or exogenous
• Signs of severe central nervous system dysfunction (coma, seizures, delirium)
• Core temperature usually > 40.5° C (105° F), but may be lower
• Hot skin common, and sweating may persist
• Marked elevation of hepatic transaminase levels
- DIC
- Renal failure
- Rhabdo
- Diarrhea
- Pancreatitis …
*8 factors that impair the body’s ability to disperse or dissipate heat and which may predispose to heat stroke
No longer a table in new Rosens, but:
Pump: cardiac disease, beta blockers
Thermoregulation: age, chronci illness, CNS bleeding
Fluid: dehydration, inadequate fluid inatke
Evaporation: vaso-occlusive clothing, anticholinergic medication, burns
Increased production: fever, exercise, NMS, drugs, thyroid storm, malignant hyperthermia, seizures
*4 complications of heat stroke
CNS - cerebral edema, seizures, coma
CVS - peripheral vasodilation and central vasoconstriction
Liver - failure
Kidney - failure
Heme - DIC
Muscles - Rhabdo
Pancreas - itis
*4 examples of burns from electrical injuries
Entrance and exit site burns: deep tissue burns may be more significant than visible tissue burns
Arc burns, kissing burns: due to current jumping across flexed surfaces of the body
Thermal burns: due to fire started by lightning
Flash burns: skin burns caused by brief flashes of electrical current or radiation
*6 physical exam findings suggestive of a lightning strike, other than burns
CNS: Apnea, LOC, amnesia, peripheral nerve damage/paralysis, keraunoparalysis, seizures, cerebellar ataxia, cognitive dysfunction, facial nerve paralysis,
CVS: Asystole, dysrhythmias, vasospasm
HEENT: Tympanic membrane rupture, hearing loss, tinnitus, vertigo, nystagmus, cataracts
Resp: Respiratory muscle/centre paralysis
GI: Pancreatitis, solid organ injury, hepatitis, rhabomyolysis
MSK: Fracture, dislocation, rhabdomyolysis, compartment syndrome, osteonecrosis
*5 potential ECG findings after a lightning injury
ST segment elevation
QT interval prolongation
Atrial fibrillation
Inverted or flattened T waves
Myocardial infarction pattern without cardiac sequelae
*What is EMSs top priority in managing the scene of a lightening strike?
- Secure the scene
- Triage
- VSA first ** as pts rarely die from lightning unless present with cardiac arrest “At some point, the intrinsic pacemaker activity of the heart brings about a resumption of cardiac activity. However, if the respiratory center has not been reactivated, hypoxia follows, and the cardiac rhythm will deteriorate into ventricular fibrillation.”
*Injuries listed – more likely caused by electrical injury or lightning?
- Rhabdo (E)
- TM perf (L)
- Keraunoparalysis (L)
- Vascular thrombosis (E)
- Pulmonary Contusion (L)
*5 ways in which lightening can injure a casualty
- Force of the strike
- Blunt trauma from being thrown
- Superheating of metallic objects in contact
- Blast-type effects and barotrauma
- Shrapnel
*Fernlike patterns of erythematous streaks
Lichtenberg figure
*6 indications for ECG monitoring in electrical injury
Not in new Rosen, but indications are listed for lightning: suspected direct strike, loss of consciousness, focal neurologic complaint, chest pain or dyspnea, associated traumatic injuries, pregnancy, and burns of the cranium or legs or on more than 10% of the total body surface area.
*4 ddx for chest and shoulder pain and mottling 24 hours post dive
DCS I
Lymphatic obstruction
Trauma?
Compartment syndrome?
?PTX
*3 things that can happen at depth
Nitrogen narcosis
Oxgen toxicity
Contaminated air
Hypothermia
Trauma
Drowning
*6 features of a dive profile
Depth
Length of the dive (bottom time)
Speed or time of ascent
Safety stop time and depth
Number of dives
Surface interval time
*1 thing you can do in the ED
100% oxygen
*Disposition
Hyperbaric chamber
*What are the formulas and descriptions for:
- Boyle’s law
- Dalton’s law
- Henry’s law
Boyle’s law: P1V1 = P2V2 (Pressure and volume are inversely proportional)
Dalton’s law: Pt = P1 + P2 + P3 … (Total pressure in a space is equal to the sum of all the gases)
Henry’s law: C=kPgas (The amount of a gas that will dissolve in a liquid at a given temperature is directly proportional to the partial pressure of that gas); this is the law that governs hyperbarics
*Scuba diver, unconscious, lateralizing to the right… 5 things on the differential
o AGE
o DCS II (involves CNS, inner ear, or lungs)
o SAH
o ischemic stroke
o CO toxicity
o post-ictal todd’s paralysis
*3 indications for hyperbaric oxygen after diving
o Decompression sickness Type 1
o Decompression sickness Type 2
o Arterial gas embolism
o Contaminated air (CO poisoning)
*One treatment to start before hyperbaric
100% oxygen
*One resource to consult
Diver Alert Network
*Diving stem: inexperienced divers dive to 130 feet (lost track of time/depth?), presents to ED with headache, malaise, lethargy onset right after surfacing, now neurologically normal. Choose the LEAST likely diagnosis:
a) DCS II
b) AGE
c) nitrogen narcosis
d) near drowning
*True or False
a At least 5% of near submersions have associated c‐spine injuries
b Antibiotics for submersion related aspiration are indicated
c DCS II commonly presents with loss of consciousness
a False
b False
c True
*Risk factors for DCS
age, obesity, fatigue, heavy exertion, dehydration, fever, cold ambient temperatures after diving, diving at high altitude, and flying after diving
*Contraindications for HBO
Not in new Rosen
-pneumothorax (untreated)
-pacemaker (can malfunction)
-claustrophobia
-history of seizures (decreases seizure threshold)
*Treatment options for DCS I
Fluids, analgesia, oxygen, HBO
*Patient is spending time at 4000 m, s/s: headache, fatigue, anorexia, dizziness: What is the diagnosis ?
AMS
*2 physiologic EARLY adaptations and what their mechanism is?
Hypoxic ventilatory response: increase in minute ventilation decreases the partial pressure of carbon dioxide in the alveolus and increases the partial pressure of oxygen in the alveolus. This results in a respiratory alkalosis; which limits the response
Hypoxemia also results in an increase in 2,3-diphosphoglycerate, causing a rightward shift of the oxyhemoglobin dissociation curve, which favors a release of oxygen from the blood to the tissues. This is counteracted by the leftward shift of the oxyhemoglobin dissociation curve caused by the respiratory alkalosis from hyperventilation.
Rapid release of catecholamines, increasing cardiac output and elevations in heart rate, stroke volume, blood pressure, and venous tone.
Erythropoietin is secreted in response to hypoxemia within hours of ascent, which in turn stimulates the production of red blood cells, leading to new circulatory red blood cells in 4 or 5 days.
*Two ways the Hb-oxygen dissociation curve changes at altitude and why?
2,3 DPG to the right to compensated by the decrease in CO2 (alkalosis) which shifts to the left
*3 non-pharmacologic ways to prevent AMS
- Slow ascent (gradual introduction of higher altitude)
- Allow time for acclimation period (ie, stay at basecamp to acclimate prior to ascent)
- Stay well hydrated
*2 treatments, their class, and mechanism of effect
Acetazolamide (carbonic anhydrase inhibitor): increases minute ventilation and enhances renal bicarb diuresis
Dexamethasone (steroid): anti-inflammatory, reduces cerebral blood flow and the release of inflammatoyr growth factors
*you decide to go on a relaxing weekend getaway vacation to the base-camp of K2. At 12,000 ft, a 28 year old male on vacation himself presents to you with headache, nausea, fatigue and malaise.
a. What could prevent this? (3)
- Gradual ascent
- Mild exercise
- Maintain hydration (not over hydrate, use balanced solution)
- Acetazolamide: 250mg BID 24H before and 1st 2 days
- Dexamethasone: 8mg first then at 4mg Q 6H if Acetaz not available
- Oxygen