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ECC Environmental Emergencies 2

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sihirlifil's version from 2018-05-02 15:20

Drowning

Question Answer
Drowning & submersion injury: pathophysHypoxemia --> intrapulmonary shunting --> V/Q mismatch
Bronchospasms
Loss of surfactant --> atelectasis
Chemical pneumonitis
what is dry drowning?victims who do not aspirate liquid into lungs (10% of the time)
Laryngospasm prevents aspiration of air (hypoxemia --> V/Q mismatch, CNS effx of hypoxia)
hypoxemia can result from what two different processes with drowning? Laryngospasm from dry drowning –no aspiration of water. Loss of surfactant –aspiration of water (alveoli stick together). Also risk bronchospasm, atelectasis, and ARDS (<--LOTS OF INFLAMMATION-->leaky capillaries-->pulm edema)
does fresh vs salt water make a difference?nope-- pathophys is the same. WASHOUT OF SURFACTANT-->atelectasis-->Intrapulmonary shunt--> Global hypoxia--> Tissue injury--> Neurologic damage--> Cardiovascular collapse--> death
why are there neuro signs with drowning?BC HYPOXIA! hypoxia-->Induces brain injury ( Severity of injury depends on duration of hypoxia)
what are the CV effects of drowning?Cardiac arrhythmias & dysfunction because of HYPOXIA-->ischemia-->acidemia-->E’lyte abnormalities (& catecholamine surge)-->Hypothermia
Myocardial hypoxia --> ischemia of mycocardium
does water type or water temp affect survival more?salt vs fresh doesnt matter, TEMP DOES
*explain how temperature of water has effect on survival ratesIf there is ICE COLD WATER (<5*C), it will INC your chances of survival, because there is a diving reflex where as cold water hits your face, the trigeminal nerve causes bradycardia, hypertension, Preferential shunting of blood to cerebral & coronary circulation----> essentially, BRAIN AND HEART PROTECTION
Triage at scene of drowningRemove from water (duh lol), wrap in blanket, mouth to snout breathing, transport to ER
explain drowning txGOAL is improve tissue oxygenation. Do CPR if indicated and able. Oxygen, intubation, mechanical ventilation. Artificial surfactant?, Antibiotics? If BAL supports. Fluid therapy? YES-- they are in SHOCK, whether it is distributive or hypovolemic. So want to restore effective circulating volume (RESTORE PERFUSION), correct acid-base abnormalities, and improve tissue perfusion. Hyperosmotic fluids if indicated based on neuro
Tx: RESPIRATORYOz: intubate, & ~PPV if PaO2 <60mmHg or SpO2 <90%
Antibx (C&S) for ALL PATIENTS b/c bact sitting in swimming pool
Artificial surfactant
Tx: NEUROHypertonic saline
Tx: CVSFluids, antiarrhythmics, defib as needed
Tx: GIOrogastric tube (reduce pressure diaphragm from belly full of water)
prog of drowning?Unknown in veterinary patients but in humans 100% mortality if Submersion > 25 minutes/CPR > 25 minutes/ Pulseless cardiac arrest on presentation to hospital (Vtach, Vfib, tachycardia, fixed pupils, respiratory arrest)
WORSE PROGNOSIS IFV-tac, fixed pupils, severe acidosis, resp arrest
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Hypothermia

Question Answer
3 mechanisms of hypothermia?Increased heat loss, Reduced heat production, Disruption of thermoregulation
explain primary vs secondary hypothermiaPRIMARY: exposure to low temps. SECONDARY: Result of disease, trauma, surgery, drug Induced alteration <--more common (both can have mild, mod or severe ranges)
Compensatory response to hypothermia =Shivering
Involuntary oscillatory skeletal activity to produce heat. Relies on glyconeogenolysis (??) or lipid/protein catabolism. Increases metab rate 4-10x baseline!
Diminished ability to compensate in who?Cachectic, young, old, thin
Compensation: why cant neonates do it well?Larger surface area = accelerated heat loss
Less lipid/protein stores for shivering
Compensation: why cant cachectic do it?Less lipid/protein for catabolism
Less fat = faster heat loss
Compensation: why cant debilitated patients do it?Inability to seek & retain heat
Inability to mount physiologic response
Rate of heat production dependent on ...metabolic rate
where is most heat generated?metabolically active systems: Brain, organs, and active muscles
3 mechanisms of heat loss (again)(1) convection (body surface to air- think fan) (2) conduction (body to object like floor) (3) radiation heat transfer (surrounding structures not in contact) (4) Evaporative heat transfer (Loss from moisture on body surfaces (respiratory tract) to envt.)
Which systems affected?
hypothermia affect on resp system? Reduced RR & depth, Pulmonary tissue injury, Oxygen dissociation disturbances, (reduced cell metabolism --> lower CO2 production in tissues= less respiratory stimulus= reduced RR, lower tidal vol --> hypoxia)
Reduced Mucociliary escalator fxn (pneumonia risk) --> pulm edema --> ARDS (worst cast scenario)
*****If core body temp drops by _________*C, leads to _________% drop in CO28* = 50% drop!
how does hypothermia affect the CV system?Inotropy: Decreased sensitivity to catecholamines --> progressive decrease contraction ability of myocardium, vasoconstrictive ability of vessels --> vasodilation --> decreased CO
Rhythm: progressive bradycardia & arrhythmias --> V-Fib at low temps
what stimulates breathing?CO2! and hypo-->dec metabolism--> dec CO2--> slow breathing
neuro effects of hypothermia?unconsciousness common, Cerebral metabolism drops 6-10% for each 1‘C decrease in core body temp! This is protective at first-- patient might appear dead (bradycardia and unconsciousness).
Neuro signs of hypothermiaAtaxia, hyporeflexia, sluggish PLRs, decreased mentation --> loss of consciousness
*****If core body temp drops by _________*C, leads to _________% reduction in cerebral perfusion1* = 6-10%
explain metabolic effects of hypothermiathere is Cold diuresis (perceived hypervolemia bc dec CO and bradycardia-- careful this can lead to dehydration). Reduction in hepatic enzyme systems (reduced metabolism). Acidosis (mixed), Immune impairment
Why does acidosis happen?Mixed resp & metabolic (reduced resp drive & perfusion --> lactate)
Reduced hepatic metabolism & renal clearance. Metabolic compensation takes a while! wont happen if no blood flow to kidneys
Metabolic effx: RENAL pathophysDiuresis (perceived increase in blood vol)
Reduced ADH responsiveness (loss H2O & e-lytes)
Metabolic effx: IMMUNOLOGIC pathophysImpaired WBC fxn
Metabolic effx: HEPATIC pathophysReduced perfusion
Reduced enzyme activity **important w/ ANX drugs**
*****If core body temp drops by _________*C, need additional _________ min of ANX recovery time2* = 40 min!!
explain primary vs secondary coagulation in the face of hypothermiaPRIMARY: Apparent thrombocytopenia due to sequestration in the spleen, Platelet dysfunction (reduced THROMBOXANE B2), Disruption of the fibrinolytic system (--> DIC!). SECONDARY: Prolongation PT, PTT. Warming blood results in NORMAL coag results!
**what should you know about the clotting probs caused by hypothermia?******ONCE PATIENT NORMOTHERMIC COAG PARAMETERS NORMALIZE (machine warming ‘solves’ problem)
how do you reheat with mild hypothermia?(32-37*C) passive rewarming (insulating blankets, slow, uses patient’s own heat) (think jrsx)
how do you reheat with moderate hypothermia?(28-32*C) active EXTERNAL rewarming + passive. forced heat, heat lamps, heated water blankets
Avoid direct contact!
AIM AT TRUNK not extremities
Complications of MODERATE rewarming treatmentVasodilation & relative hypovolemia, rewarming acidosis (built up lactate all getting circulated now)
******when you are rewarming hypothermia pt, what is super important to know about how you are doing it? where should you focus your re-warming?~***NO DIRECT CONTACT BETWEEN PT AND WARMING DEVICE-- vasoconstricted skin unable to transfer heat away= burns! FOCUS ON TRUNK
what is "rewarming shock"?Heating extremities initially causes pooling of “warm blood” in extremities, and Cool blood stays in core circulation and returns to the heart. This results in peripheral vasodilation--> HYPOTENSION AND SHOCK. ****THIS IS WHY WARMING THE CORE IS MORE IMPORTANT THAN WARMING THE EXTREMITIES
How do you rewarm a SEVERE hypothermia pt?(<28*C) ACTIVE CORE WARMING + external + passive. Warm IV fluids, Pleural –peritoneal lavage ( Fluids warmed to 104 –113 ‘F), Admin warm humidified air via face mask, ET tube, cannulas...basically want to inc core temp, can be invastive
Complications of SEVERE rewarming treatmentHge, invasive
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