p.24
Types of Decompression Sickness
What is a characteristic manifestation of Type II Decompression Sickness (DCS)?
Circulatory manifestation.
p.24
Types of Decompression Sickness
Is circulatory collapse common in Type II DCS?
No, circulatory collapse is rare.
What characterizes the disturbance stage of hypoxia?
Insufficient physiological compensation.
p.12
Time of Useful Consciousness (TUC)
What is the significance of TUC?
It represents the time from decreased O2 to when useful function is lost.
p.1
Causes of Hyperventilation
What can trigger hyperventilation?
Anxiety, panic attacks, or high altitudes.
p.6
Factors Affecting DCS Incidence and Severity
What are the factors influencing the appearance and severity of hypoxia?
Altitude, rate of ascent, duration at altitude, ambient temperature, physical activity, and individual factors.
p.2
Classification of Hypoxia
What is hypoxia?
A condition where there is a deficiency of oxygen in the tissues.
p.22
Types of Decompression Sickness
What does the mottled appearance of the skin indicate in Type 1 DCS?
A cyanotic appearance or marbling with intense pruritus (cutis marmorata) that requires recompression to resolve.
What visual effect occurs during the indifferent stage of hypoxia?
Dark adaptation is affected.
p.16
Effects of Hyperventilation
What psychomotor effect is associated with hyperventilation?
Deterioration of muscular control and coordination, especially when P a CO 2 falls below 25 mmHg.
p.14
Causes of Hyperventilation
What physiological condition results from hyperventilation?
Respiratory alkalosis with hypocapnia.
How does hypoxia affect mental processes in the disturbance stage?
Intellectual impairment, slow thinking, poor calculation ability, faulty memory, poor judgment, and delayed reaction time.
p.5
Causes of Hyperventilation
What is the main cause of hypaemic/anaemic hypoxia?
Decreased RBC count due to Fe2+ deficiency and bleeding.
p.1
Prophylaxis and Treatment of Hypoxic Hypoxia
What is the primary prevention method for decompression sickness?
Following proper ascent rates and safety stops during diving.
p.22
Types of Decompression Sickness
What is the most common manifestation of Type 1 DCS?
Deep, throbbing pain in and around the joints, commonly referred to as 'bends'.
p.4
Classification of Hypoxia
What is hypoxic hypoxia?
A type of hypoxia caused by decreased PO2 in the lungs or decreased O2 diffusion across the alveolar-capillary membrane.
p.3
Classification of Hypoxia
What is hypoxia?
A syndrome that is usually acute, resulting from inadequate oxygenation of tissue.
p.21
Bubble Effects in DCS
What do intravascular bubbles act as in the body?
Foreign bodies causing enzyme release.
p.1
Causes of Hyperventilation
What is hyperventilation?
An increase in the rate and depth of breathing, often leading to decreased carbon dioxide levels.
p.1
Decompression Sickness (DCS)
What is decompression syndrome?
A condition that occurs when a diver ascends too quickly, causing nitrogen bubbles to form in the body.
p.23
Types of Decompression Sickness
What neurological symptoms can occur with Type II DCS?
Paraplegia, monoplegia, spasticity, loss of bladder and anorectal control, muscle weakness, altered reflexes, and paraesthesia.
p.12
Time of Useful Consciousness (TUC)
What happens after TUC is exceeded?
Individuals may undergo loss of consciousness (LOC).
p.1
Prophylaxis and Treatment of Hypoxic Hypoxia
How can hypoxia be treated?
By administering supplemental oxygen and addressing the underlying cause.
p.22
Types of Decompression Sickness
What skin symptoms are associated with Type 1 DCS?
Pruritus, formication, paraesthesia, numbness, and skin crepitations caused by subcutaneous emphysema.
p.5
Classification of Hypoxia
What happens to venous HbO2 saturation in histotoxic hypoxia?
It is higher than normal due to no unloading of O2.
p.5
Classification of Hypoxia
What is stagnant hypoxia?
A condition caused by decreased circulation to the tissues.
What changes occur in respiratory rate during the compensatory stage?
Increased respiratory rate (↑ RR) and depth of respiration.
p.27
Types of Decompression Sickness
What condition must be met before flying again after Type I DCS?
Complete resolution of symptoms.
p.3
Classification of Hypoxia
What are the four types of hypoxia?
Hypoxic hypoxia, hypaemic/anaemic hypoxia, histotoxic hypoxia, stagnant hypoxia.
p.17
Decompression Sickness (DCS)
What is the doctor's role in managing decompression sickness?
To diagnose and initiate management of the condition.
p.23
Types of Decompression Sickness
What are the pulmonary symptoms of Type II DCS?
A triad of dry, progressive cough, dyspnoea, and burning substernal pain worse on inspiration.
p.20
Bubble Effects in DCS
What cardiac issues can arise from airlock in ventricles due to DCS?
Interference with cardiac contraction, leading to infarction and ventricular failure.
p.21
Bubble Effects in DCS
How do intravascular bubbles affect intravascular fluid volume?
Decreases intravascular fluid volume.
p.14
Effects of Hyperventilation
What happens to cerebral vessels during hyperventilation?
They vasoconstrict, inhibiting blood flow and O2 transport to the brain.
p.6
Factors Affecting DCS Incidence and Severity
What role does the rate of ascent play in hypoxia?
A faster rate of ascent can lead to more severe hypoxia.
p.2
Causes of Hyperventilation
What can trigger hyperventilation?
Anxiety, panic attacks, or strenuous exercise.
p.2
Decompression Sickness (DCS)
What is decompression sickness?
A condition that occurs when a diver ascends too quickly, causing nitrogen bubbles to form in the body.
p.3
Causes of Hyperventilation
What causes hypoxia?
Decreased partial pressure of oxygen in inspired air.
What are some common symptoms experienced during the disturbance stage of hypoxia?
Fatigue, lassitude, somnolence, dizziness, headache, breathlessness, and euphoria.
p.12
Time of Useful Consciousness (TUC)
Is TUC the same as the time to total unconsciousness?
No, TUC is not the time to total unconsciousness.
p.14
Causes of Hyperventilation
What mechanism does low CO2 in the blood trigger during hyperventilation?
It induces the respiratory center to inhibit breathing to retain CO2.
p.6
Factors Affecting DCS Incidence and Severity
How does altitude affect hypoxia?
Higher altitudes can increase the severity of hypoxia.
p.5
Causes of Hyperventilation
What substances can cause hypaemic hypoxia by binding with Hb?
Carbon monoxide, nitrates, and sulfa drugs.
p.25
Factors Affecting DCS Incidence and Severity
What impact does the rate of ascent have on DCS?
A faster ascent can increase the risk of DCS.
What characterizes the critical stage of hypoxia?
LOC due to circulatory failure or CNS failure.
p.20
Bubble Effects in DCS
What can occur if bubbles in DCS become too large?
They can tear and cause destruction of tissues.
What symptoms are associated with hyperventilation during the disturbance stage of hypoxia?
Hyperventilation symptoms and cyanosis.
p.21
Bubble Effects in DCS
What are the effects of serotonin and epinephrine released due to bubbles?
Causing vasoconstriction.
p.3
Classification of Hypoxia
What is stagnant hypoxia?
A type of hypoxia caused by inadequate blood flow to tissues.
p.23
Types of Decompression Sickness
What cognitive symptoms may occur in Type II DCS?
Headache, confusion, and personality changes.
p.26
Prophylaxis and Treatment of Hypoxic Hypoxia
What should you be aware of regarding DCS?
Delayed DCS manifestations.
p.6
Factors Affecting DCS Incidence and Severity
How does physical activity impact hypoxia?
Increased physical activity can exacerbate the effects of hypoxia.
What happens to cardiac output during the compensatory stage?
It increases (↑ Cardiac Output).
p.25
Factors Affecting DCS Incidence and Severity
What impact does temperature have on DCS?
Extreme temperatures can affect DCS risk.
p.19
Bubble Effects in DCS
What are 'silent' bubbles in the context of DCS?
They are bubbles that are frequently seen in moderate numbers and usually disappear without any consequences.
p.17
Decompression Sickness (DCS)
What can happen if decompression sickness is inadequately treated?
It can lead to permanent disability or death.
Which senses are affected last during the disturbance stage of hypoxia?
Hearing, which can be impaired or lost.
p.5
Classification of Hypoxia
What is hypaemic/anaemic hypoxia?
A condition characterized by decreased capacity of blood to carry sufficient O2.
p.26
Prophylaxis and Treatment of Hypoxic Hypoxia
What should you do after descending when experiencing DCS?
Land while remaining on O2.
p.26
Prophylaxis and Treatment of Hypoxic Hypoxia
What advice should be sought from a hyperbaric chamber physician?
Transport advice and possibility of recompression in a hyperbaric chamber.
p.25
Factors Affecting DCS Incidence and Severity
How does previous injury influence DCS susceptibility?
Previous injuries may increase the risk of DCS.
p.18
Decompression Sickness (DCS)
What happens to nitrogen during rapid ascent to higher altitudes?
N2 comes out of solution in the form of bubbles.
p.27
Types of Decompression Sickness
What condition must be met before flying again after Type II DCS?
Successful recompression therapy and complete resolution of symptoms.
p.12
Time of Useful Consciousness (TUC)
What does TUC stand for?
Time of Useful Consciousness.
p.3
Classification of Hypoxia
What is hypaemic/anaemic hypoxia?
A type of hypoxia resulting from reduced oxygen-carrying capacity of the blood.
p.1
Classification of Hypoxia
What are the symptoms of hypoxia?
Symptoms can include shortness of breath, confusion, and cyanosis.
p.21
Bubble Effects in DCS
What happens to blood viscosity and fibrinogen levels due to intravascular bubbles?
Increased blood viscosity and fibrinogen levels.
p.5
Classification of Hypoxia
What is histotoxic hypoxia?
A condition where tissue utilization of O2 is prevented despite normal supply, often caused by cyanides, alcohol, or narcotics.
p.6
Factors Affecting DCS Incidence and Severity
What is the significance of acclimatization in relation to hypoxia?
Acclimatization can improve tolerance to hypoxia.
p.25
Factors Affecting DCS Incidence and Severity
What role does body fat play in DCS risk?
Higher body fat can increase the risk of DCS.
p.25
Factors Affecting DCS Incidence and Severity
How does diving activity prior to flying influence DCS risk?
Diving before flying increases the risk of DCS.
p.18
Decompression Sickness (DCS)
What causes Decompression Sickness (DCS)?
Bubbles of N2 formation within body tissues and vascular spaces during rapid decrease in atmospheric pressure.
p.4
Causes of Hyperventilation
What are specific causes of hypoxic hypoxia?
1. Decreased atmospheric pressure leading to decreased PAO2. 2. Decreased pulmonary ventilation of any cause. 3. Thickening of alveolar-capillary membranes, such as from pneumonia.
p.16
Effects of Hyperventilation
What is a neuromuscular effect of hyperventilation?
Increased pH leads to increased calcium binding to plasma proteins, causing hypocalcemia and tingling sensations in extremities.
p.16
Effects of Hyperventilation
What muscular symptoms can occur due to hyperventilation?
Muscular spasms in extremities, facial muscle spasms, and generalized muscle tetany.
What personality traits may be altered during the disturbance stage of hypoxia?
Euphoria, elation, and overconfidence.
What psychomotor functions are affected in the disturbance stage of hypoxia?
Decreased muscle coordination and inability to perform fine movements.
p.17
Decompression Sickness (DCS)
What are the symptoms of decompression sickness?
Symptoms range from mild joint pain to permanent neurological deficits to death.
p.3
Classification of Hypoxia
What is hypoxic hypoxia?
A type of hypoxia caused by low oxygen levels in the air.
p.20
Bubble Effects in DCS
How can bubbles mechanically obstruct vessels in DCS?
By causing ischaemia, which can lead to neurologic symptoms.
p.14
Causes of Hyperventilation
What is hyperventilation?
A condition in which respiratory ventilation is abnormally increased, causing excessive loss of CO2.
What sensory impairments occur during the disturbance stage of hypoxia?
Impaired peripheral and central vision, uncoordinated and weak extraocular muscles, decreased range of accommodation.
p.17
Decompression Sickness (DCS)
In what situations can decompression sickness occur?
During flight decompression, altitude chamber exposure, diving, working in pressurized tunnels, or hyperbaric chamber exposure.
p.19
Bubble Effects in DCS
Why are oxygen (O2) and carbon dioxide (CO2) less involved in DCS bubble formation compared to nitrogen (N2)?
Because O2 and CO2 are consumed and excreted, while N2 is not.
p.15
Causes of Hyperventilation
What can trigger voluntary and involuntary hyperventilation?
Anxiety and apprehensive states.
p.1
Types of Decompression Sickness
What are the types of decompression sickness?
Type I (mild) and Type II (severe), depending on the symptoms and affected areas.
p.12
Time of Useful Consciousness (TUC)
How much can TUC vary?
It can vary from 30 minutes down to 9 seconds.
p.22
Types of Decompression Sickness
What are the primary symptoms of Type 1 Decompression Sickness (DCS)?
Joint pain with cutaneous and lymphatic manifestations.
p.23
Types of Decompression Sickness
What auditory symptoms can occur if Type II DCS involves the inner ear?
Tinnitus (ringing in the ear), deafness, and vertigo.
p.2
Causes of Hyperventilation
What are the main causes of hypoxia?
Causes can include high altitude, respiratory diseases, and carbon monoxide poisoning.
p.6
Factors Affecting DCS Incidence and Severity
What individual factors can influence hypoxia tolerance?
Inherent tolerance, physical fitness, emotional state, and acclimatization.
p.2
Prophylaxis and Treatment of Hypoxic Hypoxia
What should you do if decompression sickness occurs?
Seek immediate medical attention and administer oxygen if available.
What physiological changes occur in heart rate during the indifferent stage?
Increased heart rate (↑ HR).
p.13
Prophylaxis and Treatment of Hypoxic Hypoxia
What is a method of prophylaxis against hypoxic hypoxia?
Being placed in a pressurized cabin or breathing pressurized air/oxygen.
p.18
Decompression Sickness (DCS)
How does nitrogen (N2) behave under pressure according to Henry's law?
Under pressure, more N2 is dissolved in body tissues; the higher the pressure, the more N2 is dissolved.
p.18
Decompression Sickness (DCS)
Why does nitrogen diffuse out slowly from fat tissues?
Because of its higher fat solubility.
p.4
Effects of Hyperventilation
What is the result of hypoxic hypoxia?
Inhibition of aerobic metabolism.
p.16
Effects of Hyperventilation
At what P a CO 2 level do neuromuscular effects of hyperventilation typically occur?
When P a CO 2 critically reaches 24 - 30 mmHg.
p.20
Bubble Effects in DCS
What happens when bubbles displace and deform adjacent structures in DCS?
They can impinge on nerve endings, resulting in pain.
p.1
Classification of Hypoxia
What is hypoxia?
A condition where there is a deficiency of oxygen in the tissues.
p.23
Types of Decompression Sickness
What systems are involved in Type II Decompression Sickness (DCS)?
CNS, PNS, and Cardio-pulmonary system.
p.19
Bubble Effects in DCS
Why does nitrogen (N2) accumulate in the body during DCS?
Because N2 is not consumed, excreted, actively controlled, and is bound to other molecules.
p.3
Classification of Hypoxia
What is histotoxic hypoxia?
A type of hypoxia where tissues are unable to utilize oxygen effectively.
p.12
Time of Useful Consciousness (TUC)
What can individuals do during the TUC?
They can take proper corrective and protective actions.
p.14
Effects of Hyperventilation
How does alkalosis affect the neuromuscular system?
It interferes with normal O2 utilization by brain cells, causing euphoria and potentially leading to unconsciousness.
What happens to the sensations of touch and pain during the disturbance stage of hypoxia?
They are diminished or lost.
p.23
Types of Decompression Sickness
What are some additional symptoms of Type II DCS?
Ataxia, seizures, dizziness, vertigo, nausea, vomiting, and unconsciousness.
p.12
Time of Useful Consciousness (TUC)
What factors influence the variation in TUC?
Individual variations and physical activity done.
p.15
Causes of Hyperventilation
What physiological changes occur at high altitudes that lead to hyperventilation?
Decreased PAO2 and PaO2 stimulate chemoreceptors, activating the respiratory center.
p.6
Factors Affecting DCS Incidence and Severity
How does the duration at altitude influence hypoxia?
Longer durations at altitude can increase the risk and severity of hypoxia.
p.26
Prophylaxis and Treatment of Hypoxic Hypoxia
Who should be consulted for DCS treatment?
A hyperbaric chamber physician.
p.25
Factors Affecting DCS Incidence and Severity
How does the duration of time at altitude influence DCS?
Longer duration increases the risk of DCS.
p.25
Factors Affecting DCS Incidence and Severity
How does exercise and fitness level affect DCS incidence?
Higher fitness levels may reduce the risk of DCS.
p.25
Factors Affecting DCS Incidence and Severity
How does denitrogenation relate to DCS?
Proper denitrogenation can reduce DCS risk.
p.17
Decompression Sickness (DCS)
What causes decompression sickness (DCS)?
Reduced atmospheric pressure on the body leading to the formation of bubbles of inert gas (nitrogen) within body tissues.
What speech issues may arise during the disturbance stage of hypoxia?
Stammering and illegible handwriting.
p.21
Bubble Effects in DCS
What is one effect of intravascular bubbles on platelets?
Causes platelet aggregation.
p.23
Types of Decompression Sickness
What visual disturbances are associated with Type II DCS?
Blurring of vision, scotomas, tunnel vision, diplopia, and visual field defects.
p.15
Causes of Hyperventilation
How can hyperventilation and anxiety affect each other?
Hyperventilation can lead to anxiety, which in turn can aggravate hyperventilation.
p.5
Classification of Hypoxia
At what level of reduced Hb does cyanosis occur?
When reduced Hb is greater than 5 g/100ml.
p.2
Causes of Hyperventilation
What is hyperventilation?
Rapid or deep breathing that can lead to decreased carbon dioxide levels in the blood.
What are the effects of the compensatory stage of hypoxia?
Usually latent unless in prolonged exposure.
p.25
Factors Affecting DCS Incidence and Severity
What is the relationship between high-altitude diving and DCS?
High-altitude diving can increase the risk of DCS.
p.5
Causes of Hyperventilation
What are usual causes of stagnant hypoxia?
Heart failure, arterial spasm, blood vessel occlusion, venous pooling during +G maneuvers, and pressure breathing.
p.25
Factors Affecting DCS Incidence and Severity
What is the effect of age on DCS incidence?
Older age may increase the risk of DCS.
p.25
Factors Affecting DCS Incidence and Severity
How does gender affect the incidence of DCS?
Gender differences can influence DCS risk.
p.25
Factors Affecting DCS Incidence and Severity
What is the effect of repeated exposure on DCS incidence?
Repeated exposure can increase the risk of DCS.
