Question

4:03 Homework #2.docx High Altitude Simulation Test (From the article "Problems of air travel for patients with lung disease: Clinical criteria and regulations) Homework #2 1) If a patient has a pneumothorax while taking a flight at 8000 ft, what will happen to the gas trapped inside the thoracic cavity? What gas law explains why this occurs? 2) What is the normal body response to an increase in altitude? 3) Absolute contraindications to flight are? 4) Why is the use of a hypobaric chamber have an advantage over a hypoxic inhalation challenge? 5) It is suggested that individuals with a resting saturation should not fly without supplemental oxygen. 6) What is the main patient population in which most of the High-Altitude Simulation Test data is based on?

Answer 1

Q 1. If a patient has a pneumothorax while taking a flight at 8000 ft, what will happen to the gas trapped inside the thoracic cavity? what gas law explains why this occurs?

Answer 1: The gas trapped inside thoracic cavity will expand. It can be explained by Boyle's law which states that as the pressure falls, the volume of gas rises. In other words, they are inversely proportional to each other. At normal sea level pressure is 760 mmHg but when flight reach at 8000 ft it falls to 560 mmHg (approx. 25% reduction), which mean that gas trapped inside thoracic cavity will expand by 25%.

Q2. what is the normal body response to an increase in altitude?

Answer 2. At higher altitudes the amount of oxygen available decreases which results in the lower oxygen saturation in blood. Our body tackles it by various ways. one is production of red blood cells increases to counteract the lower oxygen saturation. Another one is that it redistributes blood throughout the body for example amount of blood flowing to digestive organs in decreased and to vital organs such as brain, heart and lungs is increased.

Q3. absolute contraindications to flight are

Answer 3. According to WHO absolute contraindications to flight are as follows:

1. Infants less than 48 h old.
2. Women after the 36th week of pregnancy (32nd week for multiple pregnancies).
3. Those suffering from various illness such as angina; any active communicable disease, increased intracranial pressure due to hemorrhage, trauma or infection, infections of the sinuses or of the ear and nose, recent myocardial infarction and stroke, recent surgery or injury, severe chronic respiratory disease, breathlessness at rest, or unresolved pneumothorax; sickle-cell anemia and psychotic illness.

Q4. why is the use of a hypobaric chamber have an advantage over a hypoxic inhalation challenge?

Answer 4. Reproduction of the reduction in atmospheric pressure which is almost identical and likely to be experienced during the flight is the additional advantage of hypobaric chamber over hypoxic inhalation challenge.