CPT® Code 94450

This pulmonary function test, identified by CPT® Code 94450, is designed to assess the patient's breathing response to hypoxia, which is a condition characterized by a deficiency of oxygen in the tissues. The procedure involves the use of a mask that covers the patient's mouth and nose, allowing for the controlled administration of a gas mixture with progressively decreasing levels of oxygen, specifically ranging from 20% to 12%. To ensure that the carbon dioxide (CO2) levels remain within a normal range, CO2 is added to the gas mixture during the test. As the patient inhales this gas mixture through the mask, the exhaled gases are collected and analyzed using gas analyzers. These analyzers measure the composition of the exhaled gases, providing critical data regarding the patient's respiratory function. Concurrently, the patient's peripheral artery oxygen (PaO2) levels are monitored, which can be done through pulse oximetry or by utilizing an indwelling arterial catheter. The primary objective of this test is to observe how the body reacts to decreasing oxygen levels in the inhaled air. As the oxygen concentration is lowered, the physiological responses are recorded, leading to the generation of a hypoxic response curve via computer analysis. This curve illustrates the relationship between the oxygen levels in the inhaled gas and the corresponding changes in the patient's breathing and oxygenation status. Following the test, the physician is responsible for reviewing the data collected, including the variations in exhaled gases and the peripheral artery oxygen levels, and subsequently providing a comprehensive written interpretation of the findings. This detailed analysis is crucial for understanding the patient's respiratory capabilities and potential underlying conditions related to oxygen deficiency.