Oxygen conserving methods for adults

An On-Demand Oxygen Flow Meter for Enhanced Patient Comfort and Reduced Oxygen Cost in Hospitals

Background: Hypoxemia is currently treated in hospital wards with oxygen, released continuously by "conventional" flow meters. A new type of hybrid flow meter allows to switch between on-demand and continuous mode. The aim of this observational study was to assess whether this new device reduces oxygen expenditure, is well accepted in a hospital setting and improves patient comfort during oxygen therapy. Methods: Oxygen was administered in hypoxemic patients with conventional or hybrid flow meters to maintain an oxygen saturation of ≥ 92% over a 12-week period. Every two weeks conventional and hybrid flow meters were switched. The overall oxygen delivery to the ward was continuously measured with a data logging device installed in the main oxygen pipeline and corrected for multiple confounding factors. Humidity measurements, for which a sensor placed in front of one of the nostrils, and patient questionnaires, were used to assess patient comfort during continuous and on-demand flow. Results: Overall oxygen delivery decreased by 39% when switching from continuous flow to on-demand therapy after correction for confounding factors. Continuous flows significantly decreased relative humidity more than equivalent on-demand settings and the latter tended to increase comfort. Conclusions: Hybrid flow meters cause a significant reduction in oxygen delivery in a hospital ward, which may lead to financial savings. Using the on-demand technology also lowers the dryness of the upper airways (and may increase patient comfort), while maintaining an adequate oxygenation.

Reservoir Cannulas for Pediatric Oxygen Therapy: A Proof-of-Concept Study

Hypoxemia is a complication of pneumonia-the leading infectious cause of death in children worldwide. Treatment generally requires oxygen-enriched air, but access in low-resource settings is expensive and unreliable. We explored use of reservoir cannulas (RCs), which yield oxygen savings in adults but have not been examined in children. Toddler, small child, and adolescent breathing profiles were simulated with artificial lung and airway models. An oxygen concentrator provided flow rates of 0 to 5 L/min via a standard nasal cannula (NC) or RC, and delivered oxygen fraction (FdO₂) was measured. The oxygen savings ratio (SR) and absolute flow savings (AFS) were calculated, comparing NC and RC. We demonstrated proof-of-concept that pendant RCs could conserve oxygen during pediatric therapy. SR mean and standard deviation were 1.1 ± 0.2 to 1.4 ± 0.4, 1.1 ± 0.1 to 1.7 ± 0.3, and 1.3 ± 0.1 to 2.4 ± 0.3 for toddler, small child, and adolescent models, respectively. Maximum AFS observed were 0.3 ± 0.3, 0.2 ± 0.1, and 1.4 ± 0.3 L/min for the same models. RCs have the potential to reduce oxygen consumption during treatment of hypoxemia in children; however, further evaluation of products is needed, followed by clinical analysis in patients.

[Analysis of logistical and organizational aspects of a cruise for patients with chronic respiratory insufficiency. The RESpIRA Expedition and the COPD Cruise]

Patients with chronic respiratory insufficiency who are receiving domiciliary oxygen therapy and mechanical ventilation report great difficulty in taking complex trips involving several destinations and prolonged stays away from home. Such patients share a common need for home equipment whose technology is relatively sophisticated, a condition that limits their freedom of movement. We are referring to systems for delivering oxygen therapy and mechanical respirators. Given that such patients have problems traveling by air, we hypothesized that a cruise would be an ideal alternative, given that travel would take place in the hotel itself. A cruise would facilitate the logistics of the journey, given that the equipment would have to be set up at only one setting. Working with these assumptions, we have thus far organized two cruises for chronic respiratory insufficiency patients: the "RESpIRA Expedition" and the "COPD Cruise". Our experience shows that the organizational problems to be coped with are patient recruitment, financing and choice of itinerary. With those aspects clear, organizers must then obtain the authorization of the cruise operator, including the approval of the medical and safety personnel on board. After obtaining permission for the cruise and as soon as the organizers know how many patients will travel, a list of oxygen therapy equipment (respirators and disposable supplies) must be compiled. Finally, equipment suppliers must be found. Afterwards, all that remains is to enjoy the trip. The participation of physicians responsible for domiciliary oxygen therapy and mechanical ventilation programs is essential for making patients feel safe and for assuring solutions for technical and medical problems that might arise.

Oxigenoterapia domiciliar em crianças: relato de sete anos de experiência

Objetivo: Descrever os resultados de uma experiência de sete anos com uso de oxigenoterapia domiciliar em crianças com hipoxemia decorrente de doença pulmonar crônica. Pacientes e métodos: É um estudo retrospectivo e descritivo realizado no Hospital de Crianças Santo Antonio, de Porto Alegre, Rio Grande do Sul, na região Sul do Brasil. No geral, avaliaram-se as características das crianças com oxigenoterapia domiciliar acompanhadas durante o período de janeiro de 1993 a janeiro de 2000. Resultados: Dos 40 pacientes estudados, 29 (72,5%) eram meninos. A idade de início do oxigênio no domicílio variou de dois meses a 13 anos e seis meses, sendo que 18 (45%) eram menores de um ano (média: 24,8 meses; mediana: 13 meses). As enfermidades mais prevalentes foram: bronquiolite obliterante, 31 (77,5%); pneumopatia obstrutiva crônica secundária à aspiração, três; hipogamaglobulinemia, dois; pneumopatia supurativa crônica, dois; proteinose alveolar e tuberculose, um caso cada. O tempo da última internação antes de iniciar oxigênio domiciliar variou de nove a 240 dias (média: 64 dias; mediana 50 dias). A maioria dos pacientes recebeu oxigênio por aparelho concentrador, 30 (75%), e os demais, por cilindro. O tempo de uso variou de 27 a 1.620 dias, mediana de 392,5 dias. Ocorreram cinco óbitos por complicações da doença de base e um por retirada acidental da traqueostomia. Dos 19 pacientes em que o oxigênio foi suspenso, o diagnóstico era bronquiolite obliterante em 15, pneumonia aspirativa em dois e tuberculose e proteinose alveolar um caso cada. Conclusão: Apesar da necessidade de oxigênio por períodos prolongados, a evolução foi satisfatória na maioria das crianças. Oxigênio domiciliar para crianças oxigenodependentes é uma alternativa de tratamento que permite antecipar a alta hospitalar e o retorno ao ambiente familiar.

Update on pharmacologic therapy for chronic obstructive pulmonary disease

As described throughout this article, significant improvements continue to occur in the pharmacologic management of COPD. These improvements range from improved medication targeting to better understanding of mechanisms of action, to better delivery of medications, to lower side effects. New areas of pharmacologic intervention, if not ready for use today, hold great promise for the not-too-distant future. In addition to the many agents described here, multiple mediator antagonists and anti-inflammatory agents are also under investigation for use in COPD. Interestingly, repair of alveolar tissue may be possible. Indeed, preliminary animal studies suggest that retinoic acid may be able to induce regeneration of lung alveoli. Overall, more effort is needed to broaden awareness and provide for the appropriate diagnosis of COPD, better explain pharmacologic therapies for COPD, simplify and disseminate guidelines, and highlight key differences between asthma and COPD, including their treatment strategies. As interest in COPD continues to grow, future updates on COPD management will continue to add new pharmacologic options for this devastating and preventable disease.

Nocturnal efficiency and tolerance of a demand oxygen delivery system in COPD patients with nocturnal hypoxemia

OBJECTIVES

We compared the efficacy of the standard nasal cannula and the demand oxygen delivery system (DODS) during sleep in patients with COPD.

SUBJECTS

Twenty patients with moderate or severe COPD were included in the study.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Home oxygen therapy

Home oxygen therapy has well-established benefits for patients with chronic obstructive pulmonary disease and resting hypoxemia. The indications for therapy have been clearly defined in the United States by the Health Care Financing Administration (HCFA), and these guidelines have been accepted by most third-party payers. Controversies regarding the use of oxygen during sleep and exercise when daytime hypoxemia is not present have important therapeutic and financial implications. HCFA has recently proposed a substantial reduction in reimbursement for home oxygen which could have a major adverse effect if done on a global, across-the-board, basis. Some of the new technological developments in oxygen delivery systems are presented in this article.