What age group has the most prominent mammalian dive reflex?

Children

What is the mammalian dive reflex?

 (3 components)

1. Bradycardia

2. Blood shunting to the

 CNS

3. Decreased metabolism

What is meant by “secondary drowning?”

Secondary drowning –

Death by ARDS after a drowning incident

Is drowning in salt water better than drowning in freshwater? (likely to result in a better outcome)

No

When is a drowning patient most likely to develop ARDS?

24–36 h after the incident

Can ARDS occur after a drowning, if the patient did not get any water in the lungs?

Yes

(may be a type of neurogenic pulmonary edema – mechanism not clear)

What is the main predictor of outcome in drowning?

Duration of immersion

TV shows have made much of the potential to survive drowning if the water is cold enough. In general, drowning in a water temperature <6 °C has what implication for outcome?

Better prognosis than warm water drowning

(meaning resuscitation may be possible after a longer period of time in the cold water case)

Spectacular cases of survival after very prolonged submersion are occasionally reported. What is the typical pattern in these cases?

 (3 important aspects)

Water temperatures are VERY cold

Often young children

The patient becomes rapidly hypothermic while still able to breathe, then submerged

Other than motor

vehicle collision, the

most common “accidental”

cause of death in

children is ________?

Drowning

Middle, inner, and outer ear areas can be affected by barotraumas.

Which is most serious?

Inner ear –

can produce hearing loss and vertigo/nausea/nystagmus

Is it alright for your patient with asthma to take scuba training?

Yes – IF the asthma is mild intermittent type

Other than psychosis, are there any psychiatric disorders that make scuba diving a bad idea?

Panic disorder

Should seizure disorder patients scuba dive?

Of course not!

If you are sending a patient on an air transport, and the patient has an ET tube or foley in place, what modification must you make to this equipment?

Fill with water not air

(Otherwise, the equipment is likely to fall out when the air expands and your balloons pop!)

How can you differentiate mild vs. severe hypothermia?

Severe has altered mental status

(mild has normal mental status)

What EKG wave is a buzzword for hypothermia? What does it look like?

• The Osborne or “J” wave

• An extra hump or slope on the

 down (right) side of the QRS

In a cold patient, is shivering a good or bad sign?

It is a good sign (normal heat generating response – also means that the patient is not terribly cold)

What two body systems are profoundly affected by cold, frequently leading to life-threatening complications?

1. The heart – highly prone to fatal arrhythmia when cold

2. The blood – all coagulation factors are temperature dependent (cold often produces or worsens DIC)

Are temperatures measured with a standard thermometer valid in a hypothermic or hyperthermic patient?

No – especially for cold patients, they are often not accurate.

(Use a specially calibrated thermometer with a rectal or other deep internal probe to get the “core” temp)

In a bradycardic, hypothermic patient, should you do CPR?

No –

If there is a pulse you should not do CPR. The mechanical stimulation can cause an arrhythmia

If your hypothermic patient is in V-fib, and you have shocked without success, what must you wait for before shocking again?

Core temp >85 °F

Should you perform CPR on a hypothermic patient in V-fib, while you wait for the temperature to rise?

Yes!

(CPR is avoided only if the patient has a perfusing heart beat – in a non-perfusing rhythm, some circulation is better than no circulation!)

What types of rewarming should you use for hypothermic patients?

 (3 types)

First – Passive external

Second – Active external

Third – Active core

(although none of it should interfere with resuscitation efforts)

What are passive external rewarming techniques?

Dry the patient

Remove wet clothes

Wrap in warm dry blankets

Heat lamps

(Same types of things you do in the delivery room!)

What are some active external rewarming techniques?

Warm O₂

Warm IV fluid

Forced convection (BAIR HUGGER blanket)

What are typical active core rewarming techniques?

Warm NG & foley lavage

Warm peritoneal lavage

(last ditch – fem-fem bypass or ECMO to rewarm blood externally)

If a hypothermic patient suddenly starts to generate an unusually large amount of urine output, it is called “cold diuresis.”

What transient kidney dysfunction causes cold diuresis?

Collecting duct failure to reabsorb water

Which patient groups are most at risk for hypothermia?

(5 groups: 2 “accident” types 2 medical condition groups 1 medication-related)

1. Burn patients (rapid loss)

2. Trauma patients (exposure)

3. Endocrine patients

 (hypothyroid & DM)

4. CNS & psychiatric patients

 (behavioral errors producing

 exposure)

5. Alcohol/sedative impaired

Now that Bretylium is not available, what is the drug of choice for arrhythmia in hypothermic patients?

Amiodarone

Regular defibrillation protocols cannot be followed for hypothermic patients. When can you repeat defibrillation, after the initial shock?

Core temp above 85 °F

What is “classic heat stroke?”

(5 attributes that make it classic)

1. Epidemic (during a heat wave)

2. Nonexertional

3. Seen mainly in elderly & those with

 chronic disease

4. Not sweating

5. Often causes death

There are two types of heat stroke. What are they called?

Classic & exertional

What makes exertional heat stroke different from classic heat stroke?

(2 circumstances)

(1 typical patient)

(1 exam finding)

(1 outcome)

1. Exertional happens with

 exercise

2. Isolated case, not

 epidemic

3. Occurs in healthy young

 people

4. Profuse sweating

5. Complications are

 common (but not usually

 permanent or severe)

What complications of heat stroke are most troublesome?

1. CNS damage/seizures

2. Rhabdomyolysis

 (producing kidney

 failure)

3. DIC

4. Liver dysfunction

 (diffuse)

Why do cardiac disease and beta-blocker use contribute to heat illness?

Increased cardiac output is needed for increased heat loss

What is the difference between heat exhaustion and heat stroke?

Heat exhaustion presents with

• Nausea/vomiting/diarrhea

• Salt & water depletion

• Core temperature slightly

 elevated

Heat stroke = CNS dysfunction, severe core heat (>41 °C), death or permanent consequences common

Amongst healthy patients, which ones are at especially high risk of heat illness while exercising?

• Those who cannot escape the heat

• Those who do not have adequate fluids available

• The very motivated (such as athletes)

What is the mainstay of treatment for heat stroke?

What adjunct therapy can you use in heat stroke?

Evaporative cooling (fans & water)

1. IV fluids (fluids have a lower temperature than the body temp)

2. Cool peritoneal lavage

3. Ice packs to groin &

 axillae

4. Extracorporeal cooling

 (fem-fem bypass)

Which cooling technique is thought to be more rapid in young, healthy patients of exertional heat stroke?

Cold water/ice water immersion

This technique is often not practical in the healthcare setting, as patients cannot be properly monitored & resuscitated – it is also not recommended for other types of patients, as it may be physiologically too stressful & increase mortality!

If you are treating a heat stroke patient, at approximately what temperature should you stop cooling the patient?

102 °F

(39 °C)

Why is it important to stop cooling your patient at a specific temperature?

Because the temp will continue to drop after cooling efforts end – and hypothermia worsens clotting problems

Are heat stroke patients uniformly dehydrated?

Not always

(can be a failure of thermal regulation, inability to sweat, etc.)

What medications increase the likelihood of heat illness?

(3)

1. Beta blockers (can’t ↑ cardiac output!)

2. Anticholinergics (can’t sweat)

3. Diuretics (can’t sweat – less

 fluid)

Why are pediatric patients are at increased risk for heat illness?

Heat loss mechanisms are not fully mature until puberty

(also, like very elderly or ill patients, they may not be able to obtain fluids or seek cool shelter on their own)

What are the other types of types of less serious heat illness?

(not worrisome by themselves)

(4)

1. Prickly heat (ruptured, blocked

 sweat gland)

2. Heat cramps (local Na shift)

3. Heat edema

4. Heat syncope (if nothing else

 about the syncope is

   suspicious)

If your patient’s hands or feet swell during exposure to a hot environment, is there any cause for concern?

No –

It is a self-limited, normal cutaneous vasodilation.

What causes prickly heat rash?

Blocked sweat glands rupture → erythema and pruritis

What portions of the body usually develop prickly heat rash?

Clothed areas

Why do sweat glands become blocked in prickly heat?

The moist stratum corneum becomes macerated, and blocks the ducts

How is prickly heat treated?

Oatmeal baths & antihistamines (if needed) for pruritis

What is the main concern with prickly heat rash in children?

Superinfection from the itching (requiring antibiotic treatment)

How does “heat syncope” occur?

Dehydration + either heat vasodilation or low vasomotor tone for some other reason

How is heat syncope treated?

Rest

Remove from heat

IV & PO rehydration

(remember to consider other causes of syncope, of course, before making the heat syncope diagnosis)

Five medication groups are especially likely to give you sunburn. What are the five groups?

1. Sulfas

2. Tetracyclines

3. Thiazides

4. Phenothiazines

5. Psoralens (used by

 dermatologists to create

 photosensitivity for

 psoriasis treatment)

What infectious agents are often found in burn wounds?

(one specific bug, one group of bugs)

1. Pseudomonas

2. GRAM negatives, in

 general

(of course, Staph & Strep species are also common)

Which burns require hospitalization?

1. Circumferential

2. Over a joint

3. Perineal burns

4. Significant facial burns

5. Dominant hand burns

 (if significant)

In the old burn classification system, there were 1st- through 4th-degree burns. What are the new levels, in the new system?

Superficial

Partial thickness

Full thickness

Complete

Describe a superficial burn?