Imaging studies such as X-ray and CT imaging of the chest may reveal thoracic infiltrates that can be seen as opaque patches. One distinct feature of HAPE is that pulse oximetry saturation levels (SpO2) are often decreased from what would be expected for the altitude. People typically do not appear as ill as SpO2 and chest X-ray films would suggest. Giving extra oxygen rapidly improves symptoms and SpO2 values; in the setting of infiltrative changes on chest X-ray, this is nearly pathognomonic for HAPE. Severity
The severity of HAPE is graded. The grades of mild, moderate, or severe HAPE are assigned based upon symptoms, clinical signs, and chest x-ray results for individuals. The symptoms that are taken in to account while evaluation the severity of HAPE are difficulty breathing while exerting or while at rest, the presence of a cough and the quality of that cough, and the level of fatigue of the patient. On physical exam of a suspected HAPE patient the exam findings used to grade the severity are the heart rate, respiratory rate, signs of cyanosis, and severity of lung sounds. Both symptoms and signs on physical exam can be used to evaluate a patient in the field. Chest X-rays are also used to evaluate the severity of HAPE when they are available. Differential diagnosis
Differential diagnosis:
Pneumonia
Bronchitis
Mucous plugging
Pulmonary embolism
Acute coronary syndrome
Acute decompensated heart failure
Asthma
Reactive airway disease
Exercise-associated hyponatremia
Pneumothorax

Prevention
The primary recommendation for the prevention of HAPE is gradual ascent.
In contrast, precocial animals are born with open eyes, have hair or down, have large brains, and are immediately mobile and somewhat able to flee from, or defend themselves against, predators. Primates are precocial at birth, with the exception of humans.The duration of gestation in placental mammals varies from 18 days in jumping mice to 23 months in elephants. Generally speaking, fetuses of larger land mammals require longer gestation periods. The benefits of a fetal stage means that young are more developed when they are born. Therefore, they may need less parental care and may be better able to fend for themselves. However, carrying fetuses exerts costs on the mother, who must take on extra food to fuel the growth of her offspring, and whose mobility and comfort may be affected (especially toward the end of the fetal stage). In some instances, the presence of a fetal stage may allow organisms to time the birth of their offspring to a favorable season. See also
References
External links

Prenatal Image Gallery Index at the Endowment for Human Development website, featuring numerous motion pictures of human fetal movement. In the Womb (National Geographic video). Fetal development: MedlinePlus Medical Encyclopedia