At high altitudes (typically over 2,500 meters above sea level) people expose themselves to Low air pressure and low oxygen environments (hypobaric hypoxia) during days to weeks or even longer.
In our country too, traveling by airplane, which has become extremely popular over the past few years, has further increased the number of people that are transiently exposed to a hypoxic (low oxygen) environment, as the lower limit of cabin pressure is equivalent to 2,430 m (8,000 ft) of altitude.
The normal FiO2 level (concentration of oxygen in the gas mixture that a person inhales) is 21 per cent at room air, which is the same at all altitudes. At altitudes above 2,500 metres, the barometric pressure is lower, which results in a decrease in the actual amount of oxygen that reaches the alveoli (lungs) resulting in hypoxia (less oxygen in the blood).
Therefore, the lung seeks to compensate for the lack of oxygen, by redistributing blood flow, which results in a condition termed High altitude pulmonary hypertension (also called mountain sickness). This can result in fluid oozing into the lungs one or more of the following symptoms: breathlessness on the slightest exertion, cough, haemoptysis (coughing up blood), chest tightness, fatigue, lower extremity swelling, dizziness or syncope (fainting).
Patients who present with these signs and symptoms should be evaluated by a physician at the earliest for heart failure and pulmonary hypertension.
Diagnostic tests that can be utilized are an ECG, echocardiogram, chest X-ray and pulmonary function tests
It is vital to recognize altitude-related illness symptoms, since early detection and treatment can significantly improve the prognosis. Those suffering from this condition should be strongly urged to descend to lower altitudes to lower their pulmonary artery pressures.
Before planning their trips to high altitude areas, one should take into consideration the need for acclimatization, which includes steps such as ensuring proper rest and sleep and remaining well hydrated.
Gradual acclimatization by allowing one’s body time to acclimatize to the altitude by slowly increasing your physical exertion over a few days, without strenuous activities initially also helps. It is best to avoid intoxicants, sleeping pills, alcohol and smoking. One can also consider taking appropriate medication in consultation with your physician, which can help prevent and alleviate symptoms.
The above measures would enable a traveller to enjoy the scenic beauty and landscape of the high-altitude areas without being hindered by related medical ailments. However, one should not fail to disregard warning signs and symptoms and should seek medical help at the earliest whenever necessary.
(The writer is Consultant Interventional Cardiology, Manipal Hospital Goa)
