How to Calculate the Volume of Air of a Patient

Doctors calculate patients' lung capacities to determine their pulmonary health. Several diseases reduce the lungs' volume, including pneumothorax and pulmonary fibrosis. Other diseases, such as chronic obstructive pulmonary disorder and asthma, obstruct air flow. To calculate a patient's air volume, measure how much air they expel using a spirometer. An accurate estimate then requires that you edit your result to account for the lungs' residual volume.

Things You'll Need

• Spirometer

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Instructions

• 1

  Insert the spirometer's tube into the patient's mouth.

• 2

  Instruct the patient to exhale to the fullest extent possible.

• 3

  Note the spirometer's reading after exactly one second.

• 4

  Multiply your reading by 1.25. For instance, if the patient expelled 4.8 liters of air:

  4.8 * 1.25 = 6 liters