Chest
EditorialsIntermittent Flow Oxygen Devices: Technically Feasible, but Rarely Used
REFERENCES (4)
- D Auerbach et al.
A new oxygen cannula system using intermittent-demand nasal flow
Chest
(1978) - AE Pflug et al.
Evaluation of an intermittent oxygen flow system
Am Rev Respir Dis
(1971)
Cited by (7)
Performance of a reservoir nasal cannula (Oxymizer) during sleep in hypoxemic patients with COPD
1993, ChestTo determine whether a reservoir nasal cannula (RNC) (Oxymizer) provides an arterial hemoglobin oxygen saturation as measured by pulse oximetry (SpO2) equivalent to that provided by the standard nasal cannula (SNC) during sleep in hypoxemic patients with COPD while reducing oxygen flow requirement and cost.
The study took place in a sleep laboratory for three nights, with the first night for acclimatization to the new sleeping environment. In a repeated-measures design, on the second and third nights, subjects used the SNC for one night and the RNC on another night. The order in which they received the two devices was counterbalanced.
The subjects were patients with COPD who had a stable PaO2 of 55 mm Hg or less or had a value of 56 to 59 mm Hg with evidence of cor pulmonale or polycythemia (or both) and an FEV1/FVC of less than 70 percent.
A pulse oximeter was used to measure SpO2. An arterial blood gas measurement was taken on each night while the patients with COPD were receiving oxygen therapy via the assigned device. An EEG machine was used to record measurements of electro-oculography, chin electromyography (EMG), anterior tibialis EMG and EEG. Measurements and main results: There was a statistically significant difference between mean SpO2 during sleep (RNC, 91 percent; SNC, 93 percent; F = 7.89; p = 0.01). Nocturnal SpO2 was less than 90 percent for 24.2 percent of the time with the RNC and for 17.5 percent of the time with the SNC (F = 5.41; p = 0.03), but there was no significant difference in the amount of time that SpO2 was less than 85 percent. Compared to the SNC, in 4 of 26 patients with COPD, the RNC performed better; in 12 patients with COPD, the RNC performed the same, and in 10 patients with COPD the RNC performed worse during sleep. Sleep parameters were not significantly different between the two devices.
The difference of 2 percent in mean SpO2 is within the range of SpO2 measurement error. Therefore, the two devices are equally effective when the sample is considered as a whole. Nighttime oximetry is necessary prior to prescription, since nighttime efficacy of the RNC cannot be predicted on the basis of daytime pulse oximetry.
Oxygen therapy through a transtracheal catheter has been used increasingly for the long-term delivery of continuous oxygen. Compared to nasal cannula it results in significant reduction in oxygen flow requirements. This form of therapy has gained patient acceptance because of several advantages including improved convenience, aesthetics, compliance, and mobility. Reported complications generally have been minor, including subcutaneous emphysema, cough, “mucous ball” formation and mild hemoptysis. In this report, we describe a case of granulation tissue formation at the transtracheal catheter puncture site which was treated with Nd:YAG laser bronchoscopy to reestablish patency of the upper airway. No recurrence was noted after two years of follow-up.
Pulse flow oxygen administered during early inspiration is a promising approach to oxygen conservation. Previous short-term studies show equivalent arterial PO2, 55 to 60 percent oxygen savings, and no reduction of nasal humidity when compared with continuous flow nasal cannula oxygen. This study compares the clinical efficacy of pulse flow and continuous flow oxygen in 100 patients recently hospitalized for diseases requiring O2 therapy. In an unblinded crossover design, pulse and continuous O2 were administered alternately during four 5 1/2-hour periods. Oxygen saturation was monitored continuously during the 23-hour study. Mean SaO2 on pulse flow (95.6 ±2.7 percent) was clinically the same as continuous flow (95.3 ± 2.6 percent). Mean SaO2 on pulse flow during the 30 minutes before or after each crossover (95.5 ± 3.3 percent) was similar to continuous flow during the 30 minutes near crossover (95.3 ±3.1 percent). It is concluded that the two delivery systems produce similar levels of SaO2 over the course of a day and night. Analysis of potential cost savings achieved by use of the device for a 350-bed hospital suggests a savings of about $50,000 yearly when accompanied by termination of oxygen humidification.
(Chest 1990; 97:369–72)
Chronic obstructive pulmonary disease
1988, Disease-a-MonthChronic obstructive pulmonary disease (COPD) is equated with chronic bronchitis and emphysema as one disease entity. In COPD airflow lindtation is relatively persistent unlike asthma. Tests for “small-airways disease” form no part of routine practice, for their accuracy in detecting pathological change is debatable. The proteolytic theory of the pathogenesis of emphysema highlights the role of neutrophel elastase, antielastases, oxidants, antioxidants, and thus of potential new treatments. Clinical features of COPD include breathlessness, cough, and sputum, with airflow obstruction and lung hyperinflation. The differential diagnosis includes bronchiectasis, cystic fibrosis, and pulmonary hypertension, but pulmonary fibrosis, etc., is distinguished by radiological infiltrates. Plain chest radiography cannot reliably diagnose emphysema in life, but a new method measuring lung density from the computed tomographic (CT) scan allows ration, quant tation, and diagnosis of emphysema (defined by enlargement of distal air spaces) in humans in life. “Pink puffers” with breathlessness, hyperinflation, mild hypoxemia, and a low Pco2 are contrasted with “blue bloaters” with hypoxenda, secondary polycythemia, CO2 retention, and pulmonary hypertension and cor pulmonare. Antismoking measures are a major aim in management. A bronchodilator regimen combining a slow release oral theophylline with an inhaled β2-agonist, ipratropium, and high-dose inhaled steroids is proposed because even modest improvement in obstruction can help these patients. in acute exacerbat ns with purulent sputum, antimicrobials against Streptococcus pneunundee and Hemophilus irfluenzae are used with controlled oxygen therapy aiming to keep the arterial Po2 over 50 mm Hg without the pH falling below 7.25. Influenza prophylaxis is recommended, but pneumococcal vaccination remains debatable. Chronic undernutrition in “emphysema” implies controlled trials of feeding regimens-but these remain to be assessed. Long-term oxygen therapy is the only treatment known to prolong life in blue bloaters, and oxygen concentrators and transtracheal oxygen delivery are discussed. Pulmonary vasodilators (e.g., (3z agonists, hydralazine, nifedipine, angiotensin-converting enzyme [ACE) inhibitors, etc.) have not yet been proved to provide long-term reduction in pulmonary arterial pressure. Blue bloaters have severe nocturnal hypoxemia in rapid eye movement (REM) sleep that is corrected by oxygen or the investigational drug almitrine. Combination of obstructive sleep apnea with COPD (the “overlap syndrome”) may require nasal continuous positive airway pressure (CPAP) as well as nocturnal oxygen. The value of inspiratory muscle training is not yet established by controlled trials, and the role of theophylline in improving diaphragmatic contractility remains controversial.
Options for home oxygen therapy equipment: Storage and metering of oxygen in the home
2013, Respiratory CareDomiciliary oxygen therapy
2012, Chronic Obstructive Pulmonary Disease, Second Edition