Hyperbaric Therapy and Gas Toxicity

This set of flashcards covers essential concepts regarding hyperbaric therapy, gas toxicity, and diving physiology as presented in the lecture notes.

What is Boyle's Law in relation to gas dynamics?

Boyle's Law states that for an enclosed volume of gas at a constant temperature, the pressure and volume are inversely related (PV = constant).

What are some conditions that can be treated with hyperbaric therapy?

Conditions include radiation tissue damage, clostridial myonecrosis, compromised skin grafts, crush injury, compartment syndrome, infections, acute carbon monoxide poisoning, and decompression sickness.

What is the potential risk of ascending too quickly during a dive?

Ascending too quickly can result in over-expansion of the lungs, leading to dive injuries such as arterial gas embolism or pneumothorax.

What maneuver can divers use to equalize pressure in their ears?

Divers can use the Valsalva Maneuver to open the Eustachian tube and equalize pressure.

What happens if a diver fails to equalize pressure in their mask?

Failure to equalize pressure can lead to mask squeeze, which occurs when the pressure inside the mask is lower than outside.

What is a shallow water blackout?

A shallow water blackout occurs when breath-hold divers lose consciousness due to low oxygen levels after hyperventilating before a dive.

What physiological change does hyperventilation cause before diving?

Hyperventilation decreases carbon dioxide levels (pCO2) and can lead to dangerously low pO2 levels during a dive.

What is the effect of altitude on diving and hyperbaric treatment?

Altitude can influence the efficacy of gas exchange and can lead to conditions such as high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE).

What is the purpose of a Gamow Bag?

A Gamow Bag is a portable hyperbaric chamber used to treat altitude sickness by applying higher-than-normal air pressure.

What can cause mediastinal emphysema during diving?

Mediastinal emphysema can occur when air leaks from ruptured alveoli into the mediastinum.

Describe the difference between high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE).

HAPE involves fluid accumulation in the lungs, while HACE involves fluid accumulation in the brain.

What is arterial gas embolism (AGE)?

AGE occurs when gas bubbles enter the bloodstream, blocking blood flow and causing ischemic damage.

What causes pressure-related injuries during descent and ascent in diving?

Pressure-related injuries can occur due to rapid changes in pressure affecting gas-filled spaces in the body, such as the lungs and ears.

What is the definition of decompression sickness (DCS)?

DCS occurs when dissolved gases come out of solution and form bubbles in the bloodstream due to a rapid decrease in pressure.

What effects can a cold or upper respiratory tract infection have on diving?

A cold or URTI can prevent proper equalization of pressure, leading to ear or sinus squeeze.

What is the significance of pCO2 levels before a dive?

Elevated pCO2 levels stimulate the urge to breathe; hyperventilation lowers pCO2, which can lead to decreased oxygen levels.

What can result from over-expansion of alveoli during a rapid ascent?

Over-expansion can cause rupture of the alveoli, leading to dive injuries such as air embolism.

What is bullous emphysema?

Bullous emphysema is a permanent deformation of alveoli due to expansion beyond their elastic limit, potentially without rupture.

What is a common cause of unconsciousness in breath-hold divers?

Unconsciousness can occur if pO2 levels drop below 0.1 atm due to hyperventilation and lack of proper oxygen during a dive.

What hazards are associated with the use of air-activated heat packs during diving?

Using air-activated heat packs at high pressures can cause auto-ignition, leading to burns and other injuries.

What should divers avoid to prevent ear injuries while descending?

Divers should avoid diving with an upper respiratory infection to prevent difficulties in equalizing ear pressure.

What is the effect of hyperbaric therapy on non-healing wounds?

Hyperbaric therapy can promote healing in non-healing wounds by delivering oxygen under higher pressures.

Why is it dangerous to hold your breath during an uncontrolled ascent?

Holding your breath can result in lung over-expansion and serious injuries during a rapid ascent.

What is a common injury associated with scuba diving in the context of equalization?

Sinus squeeze, which can occur if pressure is not equalized properly.

Describe the incident involving burns during the Lusitania dive.

A diver sustained severe burns due to auto-ignition of heat packs used at high pressure; the incident emphasized the dangers of using certain materials in dive suits.

What influences the urge to breathe in diving?

The urge to breathe is influenced by the levels of carbon dioxide (pCO2) in the blood.

What effects can arise from inadequate pressure equalization during a dive?

Inadequate equalization can lead to pain, injury, and conditions such as ear barotrauma.

What is the primary treatment for decompression sickness?

Decompression sickness is primarily treated with hyperbaric oxygen therapy.

What are the primary symptoms of high-altitude cerebral edema (HACE)?

Symptoms include confusion, inability to walk, and altered mental status due to brain swelling.

What role do the lungs play during the ascent in diving?

During ascent, the volume of air in the lungs must be managed to prevent over-expansion and potential injury.

How does switching from diving to altitude affect scuba divers?

Diving to high altitudes can increase the risk of DCS due to pressure changes and gas dynamics.

What medical complications are associated with a history of lung injury and diving?

Lung injuries can complicate diving experiences, increasing risks of embolisms and other pressure-related injuries.

What is the significance of using a pressure gauge in diving?

A pressure gauge helps divers monitor their depth and avoid rapid ascents that could cause injury.

What dives are most likely to result in shallow water blackouts?

Breath-hold dives, especially among inexperienced divers or those who hyperventilate prior to diving.

What is the recommended method for balancing ear pressure while diving?

The Valsalva Manoeuvre is recommended for balancing ear pressure.

What is the hazard of using goggles instead of a scuba mask during a dive?

Goggles do not allow for pressure equalization, which can lead to mask squeeze.

When should divers avoid diving altogether?

Divers should avoid diving if they are suffering from an upper respiratory infection to prevent pressure equalization issues.

What are some consequences of failing to equalize pressure?

Consequences can include pain, injury to the ears or sinus cavities, and barotrauma.

What are the primary components of hyperbaric oxygen therapy?

Hyperbaric oxygen therapy involves using increased atmospheric pressure and pure oxygen to treat certain medical conditions.

In what situations is a Gamow Bag particularly useful?

A Gamow Bag is useful for treating altitude sickness, such as HAPE or HACE.

What physiological changes occur during rapid ascent from a dive?

During rapid ascent, gas that is dissolved in blood can form bubbles causing embolism or DCS.

How do higher pressures benefit certain medical treatments?

Higher pressures enhance oxygen delivery to tissues, which can speed up healing processes for various conditions.

What essential information should divers be aware of regarding their respiratory system?

Divers should understand the impacts of pressure on gas-filled spaces in their body, including the lungs and sinuses.

What historical incident underscores the risks of heat packs in diving?

The Lusitania incident highlighted how high-pressure environments can ignite combustible materials.

How does hyperbaric therapy assist in treating carbon monoxide poisoning?

Hyperbaric therapy helps by removing carbon monoxide from the bloodstream and enhancing oxygen delivery.

What should divers do to mitigate the risk of a shallow water blackout?

Divers should avoid hyperventilation before diving to maintain balanced CO2 levels.

What is the importance of the Valsalva Manoeuvre in diving?

It helps to equalize ear pressure, preventing barotrauma and discomfort during descent or ascent.

What psychological profile is often seen in victims of shallow water blackout?

Victims often conform to a highly competitive psychological profile, driving them to risky behaviors.

What can be a consequence of ignoring ear pain during descent?

Ignoring pain can lead to more severe injuries, including perforation of the eardrum.

What physiological factor can cause users of heat packs to face risks underwater?

The combination of high oxygen levels and ambient pressure can lead to auto-ignition.

What important lesson can be learned from the RMS Lusitania incident regarding diving?

Safety protocols should include knowledge of equipment risks and consequences of using incompatible materials.

What type of injuries does hyperbaric therapy aim to resolve?

Hypoxia, gas embolism, and tissue damage related to pressure changes and oxygen supply.

What effects does hyperbaric therapy have on wound healing?

It promotes ischemic healing by improving oxygen supply to damaged tissues.

What relatives of ventilation in diving must be understood by divers?

Divers must understand the relationship between pressure, volume, and the need for proper equalization.

What conditions can lead to increased risks for scuba divers?

Conditions like respiratory infections, cold symptoms, and a lack of experience can raise risks.

What should be done in the event of a suspected air embolism during a dive?

Immediate medical assistance and hyperbaric treatment are needed for suspected air embolisms.

What external factors can complicate the safety of diving?

Environmental conditions, equipment malfunctions, and diver health can all complicate safety.

How should divers prepare for dives at different altitudes?

Divers must acclimate and understand how altitude affects diving physiology and gas ratios.

What role does understanding gas laws play in diving safety?

Knowledge of gas laws like Boyle's law prevents injuries by guiding safe ascent and descent rates.

What are the key factors for a safe ascent from a dive?

Controlled ascent rates, effective equalization, and awareness of body's gas dynamics are crucial.

What types of injuries may occur if divers do not adhere to safe diving practices?

Injuries may include barotrauma, embolisms, or hypoxic events during or after dives.

What anatomical structures are involved in pressure equalization while diving?

The Eustachian tubes and sinuses are crucial for pressure equalization.

What should divers understand about the risks of using air-filled equipment?

Air-filled equipment may pose risks due to changes in pressure and can contribute to barotrauma.

What specific symptoms might point to a need for hyperbaric therapy?

Symptoms like severe tissue damage from radiation or infections need hyperbaric intervention.

What is the primary mechanism that leads to a pneumothorax in diving?

A pneumothorax results from air leaking into the pleural space, often due to lung over-expansion.