Home oxygen therapy

A randomized, double-blind, crossover trial of the effect of oxygen on dyspnea in patients with advanced cancer

Dyspnea is a common symptom in palliative care. Despite this, there is uncertainty regarding the role of oxygen to treat the symptom in patients with advanced illness. This randomized, double-blind, crossover trial examined the effect of oxygen versus air on the relief of dyspnea in patients with advanced cancer. Following the blinded administration of air and oxygen via nasal prongs, 51 patients rated dyspnea and indicated preferences for the blinded treatments. On average, patients improved symptomatically with both air and oxygen, and there were no significant differences between the treatments. The subgroup of 17 hypoxic patients overall did not demonstrate a significant difference between air and oxygen, despite having improved oxygen saturations when administered oxygen. Hypoxia was corrected in 13 of 17 patients using the treatment dose of 4 L/min of oxygen. The experience of dyspnea is a complex, multifactorial phenomenon, with oxygen tension not correlating with the subjective experience. The administration of either air or oxygen via nasal prongs on average confers improvement of the symptom.

Continuous oxygen monitoring--a better way to prescribe long-term oxygen therapy

STUDY OBJECTIVE

The purpose of this study was to determine if an oxygen prescription based on continuous oximetry monitoring, would result in an increased percentage of time spent within an SpO2 level between 88% and 92%.

METHODS

We conducted a prospective, cohort study in an outpatient, pulmonary setting in a tertiary care referral center, on 17 patients with stable chronic obstructive pulmonary disease (COPD) who had previously been prescribed long-term oxygen therapy. The patients were monitored for approximately 24h with a portable oximeter that recorded SpO2 and EKG readings. During the initial 24h of monitoring, the patients were on their previous oxygen prescription. Their oxygen prescription was then altered based on a predetermined protocol described below. The patients were then monitored for an additional 24h.

RESULTS

Sixteen patients completed the study. Based on the initial continuous oximetry, the median oxygen prescription was reduced from 2.5 to 1.2 L/min (P < 0.001). The oxygen prescription during exercise, rest, and sleep decreased from 3.0 +/- 0.9 to 1.8 +/- 1.3 L/min (P < 0.001), 2.2+/-0.4 to 0.8 +/- 0.7 L/min (P < 0.001), and 2.2 +/- 0.4 to 0.9 +/- 0.8 L/min (P < 0.001) respectively. After the oxygen prescription was adjusted, the percentage of the time that the SpO2 was between 88 and 92% increased from 24.8 +/- 21.7% to 52.8 +/- 25.0% (P = 0.001), but the percentage of time that the SpO2 was below 88% did not change significantly (2.8 +/- 6.1% to 4.3 +/- 8.1%).

CONCLUSIONS

This study demonstrates that an oxygen prescription based on continuous oximetry monitoring results in (1) a significant increase in the percentage of time that the SpO2 is between 88% and 92%, (2) a significant decrease in the amount of oxygen prescribed, (3) a slight increase in the amount of time that the SpO2 is below 88% that was not statistically significant.

Home Oxygen Therapy: Adjunct or Risk Factor?

The use of home oxygen therapy has become increasingly commonplace and is frequently prescribed by medical specialists. In this study, we have identified a generally unexpected risk of home oxygen therapy. We performed a retrospective review of 3673 consecutive patients treated at our adult burn center over a 10-year period from 1992 to 2001. We identified 27 patients with burns directly attributable to oxygen therapy and also noted an increased incidence of these injuries over the study period. The average age of the patients was 68.1 +/- 9.2 years (range, 40-82 years). Twenty-three were using oxygen at home, three in nursing homes, and one was an inpatient in an acute care facility. Twenty-five patients (93%) were receiving oxygen therapy for the diagnosis of chronic obstructive pulmonary disease. Twenty-four patients (89%) were smoking while using oxygen, two were lighting pilot lights, and one was lighting his wife's cigarette. Four patients (15%) sustained burns greater than 10% TBSA. Seventeen patients (63%) had only partial thickness burns. Thirteen patients (48%) required admission for treatment of their burn injuries. The average length of stay for those admitted was 4.4 days. The average hospital charge for admitted patients was US dollars 8055. There were four deaths (15%), all of which were correlated only with the extent of injury. Although intuitively obvious to most health care professionals, not all patients understand that oxygen therapy and cigarettes or open flame can result in a significant injury. Although some practitioners have advocated not prescribing home oxygen for those who continue to smoke, an alternative means of reducing the incidence of this preventable complication appears warranted. Prevention efforts should focus on the counseling of patients and their caregivers as well as educating primary care physicians, nurses, and home health providers as to the dangers of oxygen use.

Effects of supplemental oxygen during activity in patients with advanced COPD without severe resting hypoxemia

STUDY OBJECTIVES

To assess oxygen desaturation during activities and to evaluate the short-term effects of supplemental O(2) use in patients with severe COPD who do not qualify for long-term O(2) therapy.

DESIGN

A double-blind, randomized, placebo-controlled trial.

SETTING

Outpatients from the pulmonary diseases division of a tertiary-care university hospital.

PATIENTS

Twenty patients with stable COPD with FEV(1)/FVC ratios of < 50%, FEV(1) levels < 55% of the predicted normal value, and PaO(2) levels of > 60 mm Hg when resting.

INTERVENTIONS

Patients were initially evaluated with pulmonary function tests, blood gas analysis, and Doppler echocardiography, and they underwent the following three 6-min walking tests (WTs) in a random sequence: basal WT (BWT); WT while breathing compressed air (CAWT); and WT while breathing O(2) (O(2)WT).

MEASUREMENTS AND RESULTS

The distance walked was recorded in meters. Dyspnea was measured by Borg scale measurement before and after the tests, and arterial oxygen saturation measured by pulse oximetry (SpO(2)) was continuously monitored. Results were analyzed by grouping patients in the following manner: desaturators (DSs) (ie, patients with a drop in SpO(2) of at least 5% and < 90% during the WT) vs nondesaturators (NDSs); and O(2) responders (ie, patients with an increase of at least 10% in the distance walked and/or a decrease of at least 3 points in Borg index score) vs nonresponders. During the BWT, 11 of 20 patients (55%) were defined as desaturators. During the O(2)WT, the SpO(2) remained at > 90% in every patient. The distance walked increased by 22% (p < 0.02), and dyspnea decreased 36% (p < 0.01) in DS patients. In NDS patients, O(2) administration reduced dyspnea by 47% (p < 0.001), but the distance walked did not improve. Responses were markedly different from one patient to another. No significant differences were noticed between the results of the BWT and CAWT in any of the groups. Thirteen O(2) responders did not differ from 7 nonresponders either in basal data or in desaturation measure during the BWT, except that all walking responders (five patients) were above the median of basal left ventricle performance.

CONCLUSIONS

Most of the studied COPD patients desaturated during the BWT. O(2) administration avoided desaturation and could increase the distance walked and reduce dyspnea, but these effects were not related to walking desaturation in individual cases. Improvements were not a placebo effect. The therapeutic role of O(2) during activities in some patients with severe COPD needs to be individually assessed.

Ambulatory oximetry monitoring in patients with severe COPD: a preliminary study

BACKGROUND

The benefits of long-term oxygen supplementation in COPD patients with hypoxemia are well established. The standard approach to prescribing oxygen uses a static assessment of oxygen requirements in a hospital or clinic setting. The assumption behind this approach is that patients will maintain a "therapeutic" hemoglobin oxygen saturation (SpO2) in the outpatient setting. We questioned the validity of this assumption, and hypothesized that many patients may demonstrate significant oxygen desaturation during normal activities of daily living. STUDY DESIGN, METHODS, AND MEASUREMENTS: We determined if oxygen supplementation maintained a therapeutic SpO2 level in patients with COPD (n = 27), using the technique of ambulatory oximetry monitoring (AOM). AOM consisted of using a portable oximeter to monitor SpO2, pulse rate, and patient activity while patients were engaged in normal activities of daily living over an extended time period (approximately 18 h). The portable oximeter collected and stored these data every 15 s over the monitored time period. Each AOM recording was manually scored for desaturation events and other key variables, including average SpO2 over the monitoring period, the average number of desaturation events per hour, and the percentage of monitored time deleted secondary to artifacts.

SETTING

University-affiliated Veterans Affairs Medical Center.

PATIENTS

All subjects were patients with stable COPD with no recent history of hospitalization or exacerbation of their lung disease.

RESULTS

This cohort of patients demonstrated a surprising frequency of desaturation below the recommended target SpO2 value (90%), which averaged approximately 25% of AOM recording time. There was wide variability among patients in the percentage of time SpO2 was below the target value (range, 3 to 67% of AOM recording time). Motion artifact on the AOM recordings was not a major problem; an average of 8% of the recording time was deleted secondary to artifacts in this patient cohort.

CONCLUSIONS

The results demonstrate that AOM is feasible and accurate with an acceptable level of motion artifact. These results also suggest that the standard approach for prescribing oxygen may lead to subtherapeutic SpO2 values in the outpatient setting. AOM holds promise as a tool to monitor the adequacy of oxygen prescriptions in the outpatient setting in patients with lung disease.

Home oxygen therapy in Medicare beneficiaries, 1991 and 1992

STUDY OBJECTIVE

Obtain descriptive data on the use of home oxygen by Medicare beneficiaries and study the impact of certain demographic factors and diagnoses on oxygen use.

METHODS

A home oxygen user was defined as any Medicare beneficiary with at least one claim for home oxygen in the Health Care Financing Administration National Claims History 5% Physician Supplier Files for 1991 and 1992. Railroad board beneficiaries, health maintenance organization members, and those without continuous part B coverage were excluded.

RESULTS

In 1991, there were 21,489 beneficiaries in the sample who received oxygen therapy. In 1992, there were 8,418 new users. Twenty-six percent of new users died in 1992. Factors significantly associated with death included age 76 years or older (relative risk [RR], 1.3), pneumonia (RR, 1.3), lung cancer (RR, 3.8), male gender (RR, 1.2), heart failure (RR, 1.3), and diagnoses suggestive of COPD (RR, 0.45). Seven percent of new users discontinued therapy within 1 month, 28% within 6 months. Liquid oxygen was used by 19% of current and 14% of new users. Factors significantly associated with liquid oxygen use included portable oxygen claims (odds ratio [OR], 2.4), nonmetropolitan residence (OR, 0.73), and white race (OR, 1.2).

CONCLUSIONS

Descriptive information on patterns of home oxygen use, including associated medical conditions, types and duration of therapy, and survival is useful for regulatory purposes. This information supports concerns that current payment policy may discourage suppliers from providing liquid oxygen in underserved areas.