Barotrauma Flashcards
what is the % breakdown of air?
21% oxygen
79% nitrogen (and others) - nitrogen is inert
What is Dalton’s law?
The pressure of a gas mixture is equal to the sum of the partial pressures of its component gases
What is the equation for Dalton’s law?
Ptotal = PO2 +PN2 + PX
Ptotal - total pressure
PO2 - partial pressure of oxygen
PN2 - PArtial pressure of nitrogen
Px - partial pressure of remaining gases
Define Boyles Law
- at a constant temperature, the volume of a given mass of gas is inversely proportional to its pressure
What is an example of a complication that arises when we interfere with Daltons Law?
Hypoxia
What is an example of a complication that can arise that is directly tied to Boyles Law?
- pneumothorax
- air embolism
Define Henrys Law
The quantity of gas dissolved in a liquid is proportional to the partial pressure of the gas in contact with liquid
What is the patho of Henrys law
decrease in atmospheric pressure, decreased pressure at alveolar level therefore less oxygen dissolving in blood
What are signs and symptoms of barotrauma of descent (aka the squeeze)
- pain (in small caviites)
- bleeding from nose or ears
- sensation of fullness
- HA disorientation
- tinnitus
What are some causes of pulmonary barotrauma
- breath holding during ascent or ascending too quickly
What does POPS stand for?
Pulmonary Over-Pressurization Syndrome.
What are some symptoms of POPS
- pneumothorax
- subcutaneous emphysema
- alveolar rupture
- air embolism
What is general prehospital care for barotrauma of ascent?
administer high flow O2
possible needle decompression or hyperbaric chamber
What is the patho of an air embolism
- Expanding air disrupts tissues
- Air forced into circulatory system
- Air passes through left side of heart
- enters systemic circulation which may
- block cerebral, coronary and other small arterioles
- block distal circulation
Signs and symptoms of an air embolism
- blood tinged sputum
- paralysis or sensory change
- aphasia
- confusion
- blindness
- seizures
- LOC
Prehospital care ofr air embolism
- ABCs - high flow O2
- transport left lateral position
- consideration for ACP
- air transport in pressurized cabin or low altitude
- hyperbaric chamner
Define Decompression Sickness
Nitrogen in compressed air converts from solution to gas, which forms bubbles in tissues and blood
Signs and Symptoms of decompression sickness
MSK
- joint pain (shoulders, elbows, knees)
- crepitus
Cutaneous
- itch, rash
Neurologic
weakness, fatigue, vertigo, paresthesia, seizures, LOC
Pulmonary
- Dyspnea
Prehospital Care for decompression sickness
- support vital function
- high concentration O2
- fluid resuscitation
- rapid transport to hyperbaric chamber if local bypass exists
Define Nitrogen Narcosis
Occurs when divers remain at depth for a prolonged period breathing compressed gas (too much nitrogen dissolved in blood)
Signs and Symptoms of Nitrogen Narcosis
- altered LOC
- impaired judgement
- slowed motor response
- euphoria
- potential memory loss
- severe cases can lead to hallucinations, coma or death
Treatment for Nitrogen narcosis
- early identification
- supportive care
- usually symptoms will reverse upon ascent
- transport
Define Acute Mountain Sickness
- happens above 8000 ft above sea level
- reduced atmospheric pressure
- hypobaric hypoxia
- associated with rapid ascent of unacclimatized person to high altitudes
Symptoms of Acute Mountain Sickness
- onset 4-6 hours after reaching altitude
- maximally symptoms within 24-48 hours
- subsides on 3rd or 4th day
- HA, tiredness, nausea, dizziness, SOB, ataxia, altered LOC
Prehospital treatment for Acute Mountain Sickness
- O2 therapy
- descent
What is the patho of a hgih altitude pulmonary edema? (HAPE)
- Pulmonary hypertension develops in response to hypoxia
- Increased SNS response and vasoconstriction
- increased capillary stress resulting in increased vessel permeability
- leakage of fluid into extravascular spaces
- occurs 24-72 hours after reaching high altitudes
Symptoms of high Altitude Pulmonary Edema
- SOB on exertion or at rest
- Crackles
- cough (may have blood tinged sputum)
- lethargic, weak
Emergency care for High altitude pulmonary edema
- oxygen/respiratory support
- descent
Define High Altitude Cerebral Edema (HACE)
- severe acute high-altitude illness
- related to increased intracranial pressure from cerebral edema (HA, ataxia, disorientation, n/v, lethargy, decreased LOC
How do you differentiate between High Altitude Cerebral Edema and Acute Mountain Sickness
- mild AMS to unconcious with HACE can occur within 12 hours
- urgent management is needed to prevent coma or death
