Demand Oxygen Delivery System Research Articles

OxySaver: highly conserving demand oxygen delivery system with increased throughput

Since the beginning of the twentieth century, oxygen has been an essential therapeutic drug. Patients with chronic lung disease and other conditions rely on supplemental oxygen provided by oxygen cylinders for treatment. Because of the sudden increase in oxygen demand caused by the COVID-19 pandemic, combined with a lack of oxygen supply, new methods of oxygen delivery have been investigated as a potential solution. We propose OxySaver, a novel low-cost (∼60$) demand oxygen delivery system that may significantly reduce oxygen consumption. The proposed system consists of a pressure sensor that detects the patient’s demand for oxygen, a normally open solenoid valve that switches the supply ON/OFF on demand, and a processing unit that ensures the supply of oxygen only during the patients’ inhalation. It is simple to install using existing oxygen cylinders and oxygen pipelines in hospitals. The preliminary prototype tests have been promising, with OxySaver able to save up to 67% more oxygen than conventional methods. OxySaver’s pulse setting can reach 18 LPM, as opposed to the 0.2–4 LPM typically found in oxygen concentrators. The system only needs 3.72 W at 50 bpm, which is less than other similar devices. OxySaver in multiplexing mode has the potential to reduce the logistical challenges associated with oxygen refilling and transport. The device is now ready for clinical testing at the bedside.

P1-31: A randomized crossover exploratory study comparing the effect of an auto-demand oxygen delivery system with that of a normal demand oxygen delivery system.

P1-31: A randomized crossover exploratory study comparing the effect of an auto-demand oxygen delivery system with that of a normal demand oxygen delivery system.

A randomized crossover pilot study comparing the efficacy of an auto-demand oxygen delivery system with that of a conventional demand oxygen delivery system in patients with chronic respiratory failure.

Introduction: When using portable oxygen, a demand oxygen delivery system (DODS), which senses the beginning of inhalation and delivers a bolus of oxygen, is often used. However, conventional DODS may not supply sufficient oxygen when reduced tidal flow fails to trigger the flow sensor. Recently, “auto-DODS,” which detects the negative pressure of inhalation and switches among 3 trigger sensitivity levels (standard, high, and extra high), has been developed to improve the efficacy of oxygenation. An auto-DODS can also supply pulsed-flow oxygen when it detects apnea, whereas a conventional DODS has only standard sensitivity. This randomized, open-label, crossover pilot study compared the performance of an auto-DODS with that of a conventional DODS.Methods: We recruited patients with chronic obstructive pulmonary disease (COPD) or interstitial pneumonia receiving long-term oxygen therapy. Interventions were performed on 2 different days for each participant. On each day, an auto-DODS or a conventional DODS were tested at rest for 30 minutes and during the 6-minute walk test. The primary outcome was mean oxygen saturation (SpO2). Secondary outcomes were the ratios of time for each sensitivity level and pulsed-flow oxygen when using the auto-DODS, total time desaturated below SpO2 90%, percentage of time desaturated below SpO2 90%, minimum SpO2, mean and maximum pulse rate, six-minute walk distance, recovery time after 6-minute walk test, modified Borg scale, comfort, and discomfort index.Results: When using the auto-DODS at rest, a high or extra high sensitivity level was observed in addition to standard sensitivity in 6 of 8 participants. During the 6-minute walk test, only standard sensitivity was observed in 6 participants. Mean SpO2 differences between the auto-DODS and conventional DODS at rest and during the 6-minute walk test were −0.6 [−4.5, 3.4] and 0.0 [−2.5, 2.5] ([95% confidence interval]), respectively, neither of which were significant (P = .73 and P = .99). There were no significant differences in secondary outcomes. There were no adverse events when using the auto-DODS.Conclusions: This study showed that the auto-DODS did not show superiority in oxygenation either at rest or during exercise compared to a conventional DODS. The auto-DODS was shown to supply oxygen safely and detect inhalations with various trigger sensitivities.

Comparison of supplemental oxygen delivery by continuous versus demand based flow systems in hypoxemic COPD patients - A randomized, single-blinded cross-over study.

Supplemental oxygen is a recommended therapy option in stable hypoxemic COPD patients. Often, supplemental oxygen is provided by continuous flow (CF). However, demand oxygen delivery systems (DODS) that provide an oxygen bolus only during inspiration have gained increasing use as they prolong oxygen cylinder life (beside battery life). However, there is a lack of evidence if different DODS and CF devices are equivalent. Seventy hypoxemic COPD patients (FEV1 32 ± 9% predicted, PaO2 56±7 mmHg) on long-term oxygen therapy were included in this prospective single-blinded, randomized cross-over trial. Following an initial incremental shuttle walk test, patients performed 3 endurance shuttle walk tests (ESWT) at 85% of their maximum walking speed in random order with: (A) CF (ESWT-CF), (B) a DODS based on liquid oxygen (ESWT-DL) and (C) an DODS oxygen concentrator (ESWT-DC). The primary outcome was oxygen saturation (SpO2) at ESWT isotime. Secondary outcomes were total ESWT duration, heart rate (HR) and breathing frequency (BF) at isotime and dyspnea at end-exercise. SpO2 at ESWT isotime was not clinically different between devices: 90 ± 4% (CF), 89 ± 5% (DL) and 90 ± 5% (DC). However, 20% of the patients showed a ≥4% lower oxygen desaturation while using a DODS device. Secondary outcomes were similar under the three conditions. Oxygen supplementation via DODS (based on liquid oxygen or as a concentrator) yielded comparable physiological effects during standardized walking in stable hypoxemic COPD patients like CF. However, 20% of patients showed a clinically relevant lower oxygen saturation while using a DODS device. Therefore, we suggest individual testing of oxygen saturation of DODS suitability.

Are Oxygen-Conserving Devices Effective for Correcting Exercise Hypoxemia?

Correction of exercise hypoxemia in advanced lung diseases is crucial and often challenging. However, oxygen-conserving devices have been introduced in the market with limited evidence of effectiveness. In the present study the efficacy of 2 oxygen-conserving devices, a pulse demand oxygen delivery (DOD) system and pendant reservoir cannula (PRC), were evaluated in subjects with COPD and interstitial lung disease (ILD). A cross-sectional, crossover study included 28 COPD and 31 ILD subjects with oxygen desaturation on the 6-min walk test (average S(pO2) < 88%). Each subject underwent 3 walk tests with DOD, PRC, and continuous oxygen flow by standard nasal cannula (CFNC), in random order, taking average S(pO2) ≥ 90% as the resaturation criterion. Exercise desaturation was corrected in 79%, 79%, and 86% of COPD subjects with CFNC, DOD, and PRC, respectively, and in 77%, 61%, and 81% of ILD subjects with CFNC, DOD, and PRC, respectively. When compared to CFNC, the oxygen-conserving devices showed similar efficacy, except a lower performance for the DOD in the ILD subjects (P = .01). Although these oxygen-conserving devices corrected exercise hypoxemia in most COPD and ILD subjects, correction was not achieved in about 20% of the severe COPD subjects, regardless of the device, and in nearly 40% of the ILD subjects with the DOD device. These findings underscore that individualized adjustment of oxygen flow is needed for optimal correction of exercise hypoxemia, especially with a DOD in an ILD patient. (ClinicalTrials.gov NCT01086891).

The effectiveness of oxygen conserving device of a demand oxygen delivery system based on FIO2 equivalency

Recently demand oxygen delivery (DOD) system has been preferred to continuous flow oxygen (CFO) method for long term oxygen therapy in patients with chronic obstructive pulmonary disease, since DOD system supplies oxygen during only inhalation and saves oxygen consumption. However, the oxygen saving ratio have not properly compared without considering fraction of inspired oxygen (FIO2), though FIO2 determines the efficacy of treatment. The purpose of this study was 1) to investigate the equivalence between the CFO method and a DOD system in terms of FIO2 with considering dead space under various breathing parameters, 2) to propose and calculate the new effective oxygen saving ratio of the DOD method, 3) to compare FIO2 obtained from calculation with that from experiment. The mathematical and experimental models of human respiratory system were developed. FIO2 was calculated depending upon various breathing parameters and the new effective oxygen saving ratio was calculated to accurately compare oxygen saving consumption between the DOD and CFO method. Results of this study have shown that as supplied volume of oxygen increased, FIO2 linearly increased. As beat per minute or tidal volume increased, FIO2 decreased. The obtained FIO2 between mathematical model and experiment showed errors less than 5% in CFO method and less than 11% in DOD method. Effective conserving oxygen ratios of the DOD system changed between 3.4 and 3.8, but had higher values when the volume of supplied oxygen was larger. In conclusion, CFO method had different equivalent values of FIO2 depending on breathing parameters. Therefore it is appropriate to take into account of FIO2 when considering performance of oxygen saving devices. The effective oxygen saving ratio proposed in this study may provide the new valuable index of oxygen saving of the DOD method while maintaining the same treatment effect compared with CFO method. In addition, the mathematical model developed in this study seems to predict FIO2 similarly as obtained using experiment.

Observance à l’oxygénothérapie gazeuse de déambulation. Évaluation et déterminants chez des patients bénéficiant d’une oxygénothérapie de longue durée

The provision of ambulatory oxygen in addition to a stationary oxygen supply has been suggested to increase adherence to long-term oxygen therapy (LTOT) and promote ambulation. The degree of adherence to ambulatory oxygen therapy and the determinants of adherence remain largely unknown. These were assessed in patients treated with LTOT (oxygen concentrator plus small oxygen cylinders with a demand oxygen delivery system [DODS]) in a tertiary care hospital supplied according to the Belgian criteria for LTOT refunding. Adherence to ambulatory oxygen was defined as mean use of ambulatory oxygen greater than 30 min/day. Patients' files were reviewed and a questionnaire was sent for assessing patients' view on the use of ambulatory oxygen. Forty-six patients were included. Mean use of ambulatory oxygen was 40±36min/day. Twenty-three patients were adherent to ambulatory oxygen according to our definition. There was no difference between adherent and non-adherent patients regarding lung function or blood gases, nor was there any correlation between mean daily ambulatory oxygen use and any parameter. However, patients with MMRC 4 dyspnoea scale had a significantly lower use of ambulatory oxygen than patients with less severe dyspnoea (mean 33±24 vs 42±39min/day ; P=0.03) despite self reporting better adherence to LTOT. Adherence to ambulatory oxygen in this series of patients is quite low but at the higher end of data reported previously. Patients with MMRC 4 dyspnoea scale had a lower use of ambulatory oxygen despite reporting better adherence to LTOT. We could not identify any other predictive factors of adherence to ambulatory oxygen.

Effect of on-demand inhalation of dry oxygen on nasal mucociliary clearance

To determine whether nasal mucociliary clearance is affected by dry oxygen delivered on demand. Saccharin nasal transit time was measured as an index of nasal mucociliary clearance. One group of patients was given dry oxygen via a nasal cannula and a demand delivery system, and another group was given dry oxygen by continuous inhalation. In each group, continuous inhalation of humidified oxygen served as the control. Saccharin transit time was measured before and after 8 hours of oxygen inhalation. The subjects were 25 patients with chronic respiratory failure who were receiving home oxygen therapy via nasal cannula. All the subjects were clinically stable (age 72.1, mean +/- SE), %VC 46.6 +/- 3.0. FEV/FVC% 9.0 +/- 1.5, PaO2 55.7 +/- 2.0 Torr. PaCO2 53.9 +/- 1.9 Torr). Saccharin transit time after inhalation of dry oxygen on demand did not differ from that after continuous inhalation of humidified oxygen (15.6 +/- 1.5 vs 14.9 +/- 1.4 min). Saccharin transit time after continuous inhalation of dry oxygen was significantly lower than that after continuous inhalation of humidified oxygen (26.6 +/- 5.4 vs 16.7 +/- 2.6 min. p > 0.05). We conclude that using the demand oxygen delivery system with a nasal cannula for 8 hours had no adverse effects on nasal mucociliary clearance.

Comparison of Two Demand Oxygen Delivery Devices for Administration of Oxygen in COPD

Demand oxygen delivery systems (DODSs) were developed to secure the mobility of patients requiring oxygen therapy. The aim of the present study was to compare the efficacy of two currently available DODS with continuous oxygen administration (CONT). Thirteen patients with COPD (mean [+/- SD] FEV1, 28 +/- 5.2% predicted; mean P(O2), 56.4 +/- 8.1 mm Hg [breathing room air]). Treatment for 30 min with CONT at a flow rate of 2 L/min, with the DODSs Oxytron 3 (Weinmann; Hamburg, Germany) or DeVilbiss EX 3000 (Somerset, PA) in random sequence. Arterialized blood samples were obtained from a hyperaemized ear lobe after 15 and 30 min. After 15 min, no significant differences in P(O2) or arterial oxygen saturation (Sa(O2)) were observed. In comparison with CONT (mean P(O2), 70.5 +/- 10.4 mm Hg; mean Sa(O2), 94.8 +/- 2.13%), oxygenation with the Oxytron 3 (mean P(O2), 66.3 +/- 10.3 mm Hg; mean Sa(O2), 93.5 +/- 2.6%) was significantly less after 30 min when measured independently by blood gas analysis and pulse oximetry. The DeVilbiss EX 3000 (mean P(O2), 69.1 +/- 12.0 mm Hg; mean Sa(O2), 94.5 +/- 3.2%) and CONT showed no differences. P(O2) did not reach equilibrium after 15 min of treatment with the DODSs. The titration of a patient to a DODS is recommended, since simply accepting the manufacturer's information on oxygen equivalent does not guarantee an adequate supply of oxygen.

Auto-Adjusting Demand Oxygen Delivery System that Minimizes SaO2 Swings Between Rest and Exertion

PURPOSE: Oxygen therapy for hypoxemic COPD patients improves survival, quality of life, and supports exercise training. Patients periodically desaturate throughout the day, as they neglect to adjust their O2 setting during exertion. This study evaluates the ability of an activity tracking/adaptive demand O2 delivery system (ADODS) to maintain SaO2 as patients change between rest and exertion.

Comparison of four demand oxygen delivery systems at rest and during exercise for chronic obstructive pulmonary disease

Objectives: The aim of this study was to assess the performance of four demand oxygen delivery systems (DODS) in improving oxygenation and effort tolerance, at rest and during exercise, in chronic obstructive pulmonary disease (COPD) patients.Materials and methods: Thirteen COPD patients were prospectively included. Four DODS (Oxiclip, Versatile, Venture and Impulse) were compared with continuous-flow oxygen (CFO).Nine of these patients performed 6-min walking tests on room air and on 3l/min oxygen by DODS and CFO; Oxygen saturation, walking distance and the Borg dyspnea score were recorded.Results: With all four DODS devices arterial oxygenation was improved with lower oxygen flow rates than with CFO. Oxygen economy was best with Impulse, but at a cost of less satisfactory oxygenation. Exercise desaturation was similar with CFO, Oxiclip, Venture, and Impulse but significantly higher with Versatile (P<0.05). Borg dyspnea scores were similar with CFO, Oxiclip, Venture, and Versatile but worse with Impulse (P<0.05). There was no significant difference in walking distances.Conclusions: All four DODS improved oxygen saturation and saved oxygen. However, performance was better with the two devices (Oxiclip and Venture) that deliver a bolus of oxygen at inspiration onset.

Effektivität von Sauerstoff-Demand-Systemen bei Patienten mit chronisch obstruktiver Atemwegserkrankung

To maintain mobility in patients with chronic hypoxemia who are under long-term oxygen therapy, portable oxygen systems are available. They have the disadvantage of a short range. To prolong the range and to reduce the cost of oxygen treatment, demand oxygen delivery systems (DODS) are used. Aim of the study was to compare three DODS (DOC-2000 [D], TransTracheal Inc.; Oxytron [O], Weinmann; Pulsair [P], DeVilbiss, Sunrise Medical) with continuous oxygen delivery. 17 patients (age 67.82 +/- 9.46 years; FEV1 1.23 +/- 0.69 l; PaO2 48.8 +/- 6.7 mm Hg) were studied. The continuous flow oxygen (CONT) and the DODS were applied to the patients for 30 minutes each in random sequence with an airflow of 2 l/min. After 15 and 30 minutes arterial blood gas analysis was done. Oxygen saturation was recorded continuously by pulseoximetry. After 15 minutes no significant differences in PaO2 were found between CONT and DODS. After 30 minutes no significant difference in PaO2 was found in CONT as compared to P. Significant lower PaO2 values were found for O and D as compared to CONT (p < 0.01). With P the range of a portable oxygen source was increased by 161.5 percent, with O by 172 percent, with D the range was increased by only 17.2 percent. Prolongation of range of a portable oxygen source can be achieved by means of DODS without a decrease of PaO2 and thus without loss of quality of the oxygen treatment. However, there are differences in efficacy between the DODS.

Nocturnal Efficiency and Tolerance of a Demand Oxygen Delivery System in COPD Patients With Nocturnal Hypoxemia

We compared the efficacy of the standard nasal cannula and the demand oxygen delivery system (DODS) during sleep in patients with COPD. Twenty patients with moderate or severe COPD were included in the study. Four consecutive polysomnographic recordings were performed under the following conditions: DODS powered by compressed air (night 1 [N1]); oxygen delivered with a nasal cannula alone (night 2 [N2]); oxygen delivered through a DODS (night 3 [N3]); and oxygen delivered with nasal cannula alone (night 4 [N4]). Oxygen flow rates with and without DODS were adjusted the day before the first night so that the resulting transcutaneous arterial oxygen saturation (SaO2) was > or = 95%. The following parameters were evaluated each night: apnea-hypopnea index, nocturnal SaO2, total oxygen saving, and several neurophysiologic parameters. The oxygen saving with the DODS was, on average, 60%. All parameters obtained during N2 and N4 (oxygen alone) were identical. The percentage of total recording time spent at SaO2 > or = 95% was comparable between N2 ([mean +/- SD]; 69+/-32%) and N3 (61+/-31%) (difference is not significant [NS]), as was the time spent at SaO2 between 90% and 95% (N2, 29.8+/-31%; N3, 35.9+/-27%; NS) and < 90% (N2, 0.75+/-2.6%; N3, 2.5+/-8.6%; NS). Although the mean response time was not significantly different between N2 and N3, two patients experienced a substantial increase in response time with an SaO2 < 90% on the DODS. The DODS device did not induce any difference in the percentage of time spent in rapid eye movement (REM) sleep (N2, 12.3+/-8.7%; N3, 16.4+/-7.8%; NS) or non-REM sleep (N2, 87.7+/-8.7%; N3, 83.7+/-7.9%; NS). Non-REM distribution in stage 1-2 sleep and in stage 3-4 sleep was comparable between N2 and N3. Similarly, no difference was observed for the sleep efficiency index (N2, 71+/-15%; N3, 69.6+/-14%; NS). Differences between sleep onset latency times were NS. In a majority of moderate to severe COPD patients, the use of a DODS device does not induce any significant alteration of nocturnal neurophysiologic and ventilatory profiles. However, the presence of nocturnal desaturation in a few patients justifies the need to systematically perform a ventilatory polygraphic recording when prescribing a DODS device.

Efficacy of portable liquidoxygen system with demand oxygen delivery system

Efficacy of portable liquidoxygen system with demand oxygen delivery system

Demand Oxygen Delivery for Patients with Restrictive Lung Disease

The demand oxygen delivery system has been reported to improve oxygen delivery 7:1 vs steady flow during rest and exercise in COPD patients. The present study evaluates the DODS during rest and exercise in eight patients with restrictive lung disease. It was concluded that the DODS provides substantial oxygen savings in RLD patients, particularly during exercise.

Low-concentration Oxygen Therapy Via a Demand Oxygen Delivery System

Recent heightened concern about the costs of medical care has stimulated research and development in devices and schemes for saving costs while retaining quality of care. Consistent with that concern is the fact that standard steady-flow oxygen delivery is so wasteful. Almost its entire benefit occurs at the very beginning of inspiration. We compared the efficacy of nasal oxygen delivery via a new demand oxygen delivery system (DODS) with the standard steady-flow (SF) method. The DODS incorporates a valve and sensor interposed between the oxygen reservoir and the patient, which meters oxygen to the patient only during early inspiration. Twelve COPD subjects with hypoxemia at rest received oxygen at flow settings of 1 to 4 L/min via SF and at various breath interval settings via the DODS method, calculated to match the above spectrum of the SF. We measured oxygen delivery using an ear oximeter. The results indicate that significantly less oxygen was required to provide equivalent saturations using the DODS compared with the SF method (p less than .001). The mean comparative savings in oxygen is better than seven to one favoring the DODS over the SF method. Further study is warranted, since the widespread use of such a device could result in substantial cost saving while increasing the range of portable oxygen delivery.