Long-Term Oxygen Therapy Outpatient Considerations

Clinical Indications Persistent hypoxemia in a clinically stable patient that is otherwise optimally managed. Defined as SpO2 ≤ 88% or PaO2 ≤ 55 mmHg. Exceptions are made for patients who do not meet the above in the setting of cor pulmonale. These are medicare indications, which are discussed in more detail later. HCT > 55% Clinical evidence of RH failure. ECG evidence of P pulmonale (RA enlargement)

Evidence Best data are in COPD literature, all other indications are extrapolated, supported by small studies with surrogate endpoints in other diseases. Four RCTs NOTT (Ann Intern Med, 1980) MRC (Lancet, 1981) Gorecka et al (Thorax, 1997) Chaouat et al (Eur Respir J, 1999) NOTT, MRC studied more severe hypoxemia, found survival benefit. Other two were moderate hypoxemia, and demonstrated no survival benefit.

NOTT 203 patients with COPD and hypoxemia from 6 centers. PaO2 ≤ 55 or ≥59 with cor pulmonale. Nocturnal vs continuous (≥ 15 h/day) O2 titrated 1-4 LPM to PO2 60-80. Increased 1 LPM for sleep. Continuous Nocturnal Nocturnal oxygen treatment trial. Coordinated by Petty at CU. Particular benefit in patients with MPAP < 27, PaCO2 ≥ 43, preserved exercise capacity, and higher incidence of neuropsych or mood impairment by standard testing.

MRC 87patients with COPD and hypoxemia from 3 UK centers. PaO2 40-60. Continuous (≥ 15 h/day) O2 titrated to PO2 >60-80 vs no O2 controls. Medical research council.

2 Negative Studies in Moderate Dz Gorecka (Poland) Chaouat (Europe) 135 patients, 9 centers. PaO2 56-65 No O2 vs ≥ 17 h/day O2 titrated to PaO2 >65 No difference in 1, 2, and 3 year survival Survival in controls comparable to that of O2 groups in MRC and NOTT 76 patients, 6 centers. PaO2 56-69 with nocturnal desat < 90% but without OSA. Nocturnal O2 8-10 h/night, titrated to sat >90% No difference survival up to 5 years, nor in need for daytime LTOT ( PaO2 < 55) LTOT and NOT not beneficial for patients with mild hypoxemia.

Medicare/Medicaid Considerations Group I: PaO2 ≤ 55 mmHg or SpO2 ≤ 88% on room air at rest, sleep, or with exercise. Also: Sleep: normoxemic by day, but desat > 5% or >10 mmHg PaO2 “with symptoms or signs reasonably attributable to hypoxemia (e.g., impairment of cognitive processes and nocturnal restlessness or insomnia)” Must document correction of hypoxemia and dose (rest, sleep, exercise). If only nocturnal hypoxemia, CMS only covers stationary (concentrator). If only exertional hypoxemia, CMS only covers portable.

Medicare/Medicaid Considerations Group II: PaO2 56-59 mmHg or SpO2 > 88% on room air at rest, exercise, or sleep if there is evidence of cor pulmonale, PH, P pulmonale, peripheral edema, or HCT >55%.

Physician Documentation You must document abnormal oxygen findings in your note, along with correction of these findings and at what dose and in what state with supplemental oxygen. You must fill out the CMS certificate of medical necessity (CMN). You must document an etiology for hypoxemia and code for it in your billing. Hypoxemia alone doesn’t cut it.

 

Oxygen Therapy Clinic Follow-up You must see the patient and fill out the CMN at least annually. You do not necessarily need to retest for CMN, but as the clinical scenario dictates, retesting and prescription change may be appropriate.

Concentrators Works on the principle of cyclic nitrogen adsorption to aluminosilicate matrix under high pressure, collection of nitrogen-poor filtrate (O2, argon), and nitrogen desorption upon pressure release. Low end stationary devices go up to 5 LPM, newer devices can get to 10. Inogen One is an example of a portable concentrator (more later).

Portable (vs Ambulatory) Ambulatory (CMS does not recognize) devices should weigh less than 4.5 kg. Compressed O2 in C, D, (shoulder bag) or E cylinders (20 lb, with a cart) Home-fill liquid O2 (dewar or concentrator) Portable concentrator – battery powered. Limited by battery life and number of batteries. (Insurance issues?)

Conserving Device Reservoir – Pendant, Oxymizer. Transtracheal O2 – Eliminates deadspace of pharynx and proximal trachea. Demand pulse conservator – senses inspiratory flow and delivers a pulse of oxygen. Patient must be tested on the device as it will likely alter the prescription.

Travel with Oxygen Portable concentrators are the only devices FAA approved for air travel. Need to calculate battery life with regard to flight time. Cabins generally pressurized from 5,000-10,000 feet. Patients should carry copies of their air travel O2 prescription. Physician statement should be sent to the airline at least 10 days prior to flight.

Beyond LTOT Coexistence and comorbidity of sleep disordered breathing (SDB) is relatively common in COPD (~20%). These patients should be evaluated conventionally. Nocturnal NIPPV may be of utility in a subset of patients with COPD without SDB. Principles include respiratory muscle rest and blowing of CO2 retained during the day.

NIPPV in COPD - Evidence NIV in hypercapneic COPD patients improves daily PCO2, QOL, exercise tolerance. Small studies, systematic review. AVCAL – NIV improved sleep quality, mortality up to 36 months (then curves converged), but worsened QOL. Parasathy et al. Single center eval of multifaceted QI program including AVAPS reduced hospital readmission for COPD exacerbation over 12 months in patients who had had 2 admissions in the previous 12 months.

Mouthpiece Ventilation Case-control study found that mouthpiece and conventional NIPPV similarly reduced the risk of intubation in acute exacerbations of COPD. Mouthpiece ventilation was better tolerated than conventional NIPPV in another small COPD exacerbation study. Mouthpiece ventilation may be a reasonable alternative for patients with COPD exacerbation that do not tolerate mask ventilation.

NIPPV (BiPAP, E0470) in COPD: CMS ABG on pt’s O2 Rx with PaCO2 ≥ 52. Nocturnal oximetry with SPO2 ≤ 88% for ≥ 5 cumulative minutes over ≥ 2 hours of recording time. PSG excludes OSA. For coverage beyond first 3 months, requires face-to-face encounter between 31 and 91 days documenting improvement in sx and adherence (4h per night, ≥70% of ≥ 30 nights).

NIV with backup rate (E0471) in COPD Documentation of medical necessity due to severe or life-threatening disease. PaCO2≥ 49 or FEV1 ≤ 50% OR PaCO2 45-48 or FEV1 51-60% AND ≥ 2 respiratory hospitalizations in the past 12 months. No follow up or adherence requirements.

Resources General - http://www.nlhep.org/Pages/Default.aspx Air travel - http://www.airlineoxygencouncil.org/?page_id=17 CMS O2 - https://www.cms.gov/Outreach-and-Education/ Medicare-Learning-Network MLN/MLNProducts/Downloads/ Home-Oxygen-Therapy-ICN908804.pdf CMS PAP - https://www.cms.gov/Outreach-and-Education/ Medicare-Learning-Network-MLN/MLNProducts/downloads/ PAP_DocCvg_Factsheet_ICN905064.pdf CMS NIV - https://www.cgsmedicare.com/jc/mr/pdf/ mr_checklist_rad_e0471.pdf underscore underscore