Environmental Emergencies Quiz

Questions and Answers

Which factor causes a decrease in PaO2 at high altitudes?

Increased water vapor pressure

Decreased venous return

Increased carbon dioxide levels

Decreased atmospheric pressure (correct)

What is a common characteristic of heat exhaustion?

Profuse sweating and decreased blood pressure (correct)

Altered consciousness and increased heart rate

Severe muscle cramps

Fever above 40.5°C

Which condition is specifically associated with hypoxia due to diffusion limitation?

Pulmonary fibrosis (correct)

Asthma

Chronic obstructive pulmonary disease

Cyanide poisoning

Which of the following is typically increased during exercise?

Ventilation rate Signup and view all the answers

What is the primary physiological change associated with altitude sickness?

Hyperventilation leading to respiratory alkalosis Signup and view all the answers

What is a common result of V/Q mismatch in the lungs?

Decreased arterial oxygen saturation Signup and view all the answers

Which of the following describes caisson disease?

Arthritis secondary to nitrogen bubble formation Signup and view all the answers

What happens to 2,3 BPG levels at high altitudes?

Increased levels help facilitate oxygen release Signup and view all the answers

Study Notes

Environmental Emergencies

Altitude Effects: Increased FiO2, decreased Pao2, and hyperventilation lead to respiratory alkalosis.
2,3 BPG Increase: Enhances oxygen release from hemoglobin, aiding in adaptation to high altitudes.
Pulmonary Vascular Resistance (PVR): Elevated due to hypoxia and vascular constriction.
Acute Mountain Sickness: Symptoms include headache, dizziness, and nausea due to rapid ascent in altitude.
HAPE (High-Altitude Pulmonary Edema): Characterized by fluid accumulation in lungs; medical interventions include rapid descent and possibly steroid treatment.
HACE (High-Altitude Cerebral Edema): Severe neurological impairment requiring immediate descent and hyperbaric oxygen treatment.
Hypothermia: Heat cramps arise from electrolyte loss, while heat exhaustion results from dehydration and decreased blood pressure.
Heat Stroke: Occurs at temperatures above 40.5°C, leading to altered consciousness and potential multisystem failure.
Frostbite: Results from extreme cold exposure; treatment includes gradual rewarming.

Exercise and Diving

Exercise Effects: Increases heart rate, stroke volume, and pulmonary blood flow, maintaining a uniform V/Q ratio.
Diving Risks: Includes barotrauma and caisson disease from nitrogen bubbles; slow ascent necessary to prevent decompression sickness.

V/Q Ratio and Hypoxia

Hypoxia Definition: Reduced oxygen delivery to tissues due to factors such as cardiac output, hypoxemia, and anemia.
Inspired Oxygen Tension (PIo2): Calculated as PIo2 = FiO2 x P - PH2O; altitude affects this relationship with decreased partial pressures.
Hypoventilation Mechanisms: Results in increased Paco2 from CNS depression, obesity hypoventilation syndrome, or neuromuscular disorders, diminishing oxygen supply.
Diffusion Limitation: Seen in conditions like pulmonary fibrosis, can present with normal or increased A-a gradients.
V/Q Mismatch: Normal perfusion with abnormal ventilation, typically seen in conditions like COPD, pulmonary edema, or embolism, leading to hypoxia.

Description

Test your knowledge on the effects of altitude and hypothermia on human health. This quiz covers acute mountain sickness, high-altitude pulmonary edema, and cerebral edema, as well as heat-related illnesses. Understand the physiological responses and medical interventions critical for survival in extreme environments.