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Pulse Oximetry in Primary Care Setting

Author: Article Date: 1/8/2007

In the early 1980s pulse oximetry was introduced and is now commonplace in the emergency and acute care market. It has become the standard non-invasive method of determining arterial oxygen saturation because of its simple functionality and high clinical value. Pulse oximetry has been on the increase in primary care settings as well. Small, inexpensive pulse oximeter units have changed the way primary care physicians evaluate, manage, and treat patients. It provides the physician with a quantitative assessment and measurement with which to manage patients’ chronic and acute illnesses.

Pulse oximetry procedures are billed under separate current procedural terminology (CPT) codes, and can be used in conjunction with other office and outpatient evaluation and management codes. Office staff can be easily trained to perform pulse oximetry, thereby increasing physician patient time, and office and physician revenue.

Pulse oximetry is a noninvasive measurement of arterial oxygen saturation. It measures oxygen saturation within the patient’s hemoglobin using both red and infrared light. The amplitudes of the light signals are measured and mathematically calculated to give oxygen saturation as a percentage. The medical device industry has created an apparatus standard for pulse oximetry. Pulse oximetry accuracy specifications are +/-2 digits. Although pulse oximetry readings may differ from manufacturer to manufacturer based on their proprietary algorithm, all must meet the industry’s device specifications. This value may be affected by other molecules that bind to the patient’s hemoglobin, like carbon monoxide, which produces a higher measurement of saturated hemoglobin. These high levels produce an inaccurate oxygen saturation reading on the pulse oximeter. Values obtained by pulse oximetry that do not correlate with the patient’s physical findings must be confirmed by arterial blood gas in a laboratory.

The patient with Chronic Obstructed Pulmonary Disease (COPD) may benefit from pulse oximetry with each primary care office visit. Pulse oximetry measurement gives the physician a baseline to evaluate and confirm clinical findings. Decreased oxygen saturation readings from the patient’s normal baseline can be an early identifier of infection, medication non-compliance, and disease exacerbation. In conjunction with the patient assessment, the oxygen saturation obtained by pulse oximetry may help avoid hospital admissions. Some COPD patients with hypoxemia may require long term oxygen therapy.

Patients who have oxygen saturations below 88% at rest, or have saturations below 88% with activity with a baseline reading of 89% or below qualify for home oxygen therapy under Medicare guidelines. These patients may need to be qualified or re-qualified periodically for home oxygen therapy. The primary care office can perform a baseline and exercise oximetry to qualify patients for home oxygen. Some oximeters like the Smiths 3401 FingerPrint® have a built-in printer that can assist the clinician in recording multiple measurements during exercise oximetry. Exercise oximetry is billed under CPT code 94761.

Patients diagnosed with COPD with substantial disease progression now have purchased small inexpensive pulse oximeters, like the Smiths 3420 Digit® oximeter. These small pulse oximeters assist the patient in monitoring their symptoms and oxygen saturation for early signs of infection or exacerbation, and they can notify their physicians of acute changes.

Patients can be instructed to record their oxygen saturation at specific times with certain activities, keeping records of their oxygen saturation readings for their physicians’ and other health care providers’ review.

The physician needs to write a prescription for these devices, and the patient may be reimbursed by some insurance plans.

Primary care physicians treat patients with pneumonia in their office on a routine basis. The pulse oximeter assists the physician in determining the severity of the disease and provides documentation to support hospital admission. Patients with aggressive pneumonias may present with decreased oxygen saturation levels and shortness of breath. Pulse oximetery helps quantify the need for hospital/acute care admission and supports the clinical findings of the physician.

The pulse oximeter can be used by the primary care physician as a screening tool for possible sleep disorders when used in conjunction with a patient history. Some portable pulse oximeters have the ability to record and store readings over a 24 hour period. Patients can be sent home with battery powered oximeters for an overnight recording of oxygen saturation. The patient places the oximetry probe on their finger and turns on the oximeter for an overnight recording at their normal bedtime.

The patient then returns the oximeter to the office the next day for downloading of the overnight information. A physician then can evaluate if the patient had any desaturations and the severity and length of these events. Frequency, severity, and length of the patient desaturation will determine the patient’s risk and need for subsequent overnight sleep testing. Reports generated by most portable oximeters are easy to read and quantify. These oximeters may require a PC, software, and printer in order to generate a report.

Pulse oximetry can be useful in treating infant and pediatric patients in the primary care setting. Infants with Respiratory Syncytial Virus (RSV) and other respiratory problems can present with increased respiratory rates, retractions and low oxygen saturation levels. Pulse oximetry can be a useful assessment tool in evaluating the severity of the illness, and the need for acute care intervention. Children with asthma and allergies can present with disease exacerbation where the evaluation of oxygen saturations can be helpful to assess disease severity. Pediatric patients with sleep disorders may also benefit from overnight oximetry screening to assess for obstructive sleep apnea, and other disorders.

Reimbursement for pulse oximetry in the primary care setting can be billed in addition to normal evaluation and management CPT codes. There are three CPT codes that can be used in the primary care setting for pulse oximetry.

A single spot check can be billed under CPT 94760, and multiple measurements for exercise oximetry can use CPT 94761. Overnight sleep screening with a pulse oximeter can use CPT 94162. All three of these procedural codes can be billed in conjunction with Evaluation and Management (E&M) codes.

Routine screening of all patients with pulse oximetry is not billable under these three CPT codes. The physician must show clinical justification for each test. Physicians cannot bill for the evaluation and review of the overnight pulse oximerty study, but can incorporate their interpretation time within the standard E&M visit codes.

The pulse oximeter is a valuable tool for the primary care physician. The clinical information that the pulse oximeter provides can be beneficial for the evaluation and management of different diseases. Pulse oximetry can help justify acute care intervention and placement, and help determine severity of a disease process. It can be used as an overnight screening tool for sleep disorders at a relatively low cost to the patient. A pulse oximeter is a dependable device that needs little maintenance, and can become an indispensable tool for the primary care physician.



References

Blonshine, S., Brown, R., et al. AARC clinical practice guidelines: pulse oximetry. Respiratory Care. 1991; 36: 1406-1409.

Booker, R. Pulse oximetry in primary care. The Airway Journal. 2004; 2(3)

Chatburn, R., Kallstrom, T., & Volsko, T. Evaluation of a commercial standard for checking pulse oximeter performance. Respiratory Care. 1996; 41(2).

Hannhart, B., Michalski, H., et al. Reliability of six pulse oximeters in chronic obstructive pulmonary disease. Chest. 1991; 99: 842-846.