Home oxygen therapy: re-thinking the role of devices

Evaluation of a portable, lightweight modular system to deliver high inspired oxygen to trauma casualties without the use of pressurised cylinders

INTRODUCTION

Administering supplemental oxygen is a standard of care for trauma casualties to minimise the deleterious effects of hypoxaemia. Forward deployment of oxygen using pressurised cylinders is challenging, for example, logistics (weight and finite resource) and environmental risk (fire and explosion). Oxygen concentrators may overcome these challenges. Although previous studies successfully demonstrated fractional inspired oxygen (FiO2) >0.8 using oxygen concentrators and ventilators, the systems did not fulfil the size, weight and power requirements of agile military medical units. This study evaluated whether a modular system of commercially available clinical devices could supply high FiO2 to either ventilated or spontaneously breathing casualties.

METHODS

As a proof of principle, we configured an Inogen One G5 oxygen concentrator, Ventway Sparrow ventilator and Wenoll rebreather system to ventilate a simulated lung (tidal volume 500 mL). Casualty oxygen consumption (gas withdrawal inspiratory limb) and carbon dioxide (CO2) production (CO2 added expiratory limb) were simulated (respiratory quotient of 0.7-0.8). Three circuit configurations were evaluated: open (supplementary oxygen introduced into air inlet of ventilator); semiclosed (ventilator replaces rebreather bag of Wenoll, oxygen connected to either ventilator or Wenoll); and semiclosed with reservoir tubing (addition of 'deadspace' tube between ventilator patient circuit and Wenoll). Data presented as mean and 95% reference range.

RESULTS

There were modest increases in FiO2 with increasing Inogen settings in 'open' configuration 0.23 (0.23-0.24) and 0.30 (0.28-0.32) (Inogen output 420 and 1260 mL/min, respectively). With the 'semiclosed' configuration and oxygen added directly into rebreather circuit, FiO2 increased to 0.36 (0.36-0.37). The addition of the 'reservoir tubing' elevated FiO2 to 0.78 (0.71-0.85). FiO2 remained stable over a 4-hour evaluation period. Fractional inspired carbon dioxide CO2 increased over time, reaching 0.005 after 170 (157-182) min.

CONCLUSION

Combining existing lightweight devices can deliver high (>0.8) FiO2 and offers a potential solution for the forward deployment of oxygen without needing pressurised cylinders.

Recent trends in the nanozeolites-based oxygen concentrators and their application in respiratory disorders

Medical-grade oxygen is the basic need for all medical complications, especially in respiratory-based discomforts. There was a drastic increase in the demand for medical-grade oxygen during the current pandemic. The non-availability of medical-grade oxygen led to several complications, including death. The oxygen concentrator was only the last hope for the patient during COVID-19 pandemic around the globe. The demands also are everlasting during other microbial respiratory infections. The yield of oxygen using conventional molecular zeolites in the traditional oxygen concentrator process is less than the yield noticed when its nano-form is used. Nanotechnology has enlightened hope for the efficient production of oxygen by such oxygen concentrators. Here in the current review work, the authors have highlighted the basic structural features of oxygen concentrators along with the current working principle. Besides, it has been tried to bridge the gap between conventional oxygen concentrators and advanced ones by using nanotechnology. Nanoparticles being usually within 100 nm in size have a high surface area to volume ratio, which makes them suitable adsorbents for oxygen. Here authors have suggested the use of nano zeolite in place of molecular zeolites in the oxygen concentrator for efficient delivery of oxygen by the oxygen concentrators.

Outpatient surveillance programme for health workers with COVID 19 in Mexico: an observational study of ambulatory treatment and early hospitalization

Introduction:

International guidelines recommend hospital care for patients with severe Coronavirus disease (COVID-19), but fragile health care systems struggle to cope with high number of admissions, placing patients at risk of receiving substandard care. We describe an outpatient ambulatory surveillance and treatment strategy (OPAT) for health care workers (HCWs) with severe COVID-19 during low hospital bed availability periods in Mexico City.

Methods:

In this observational, descriptive, retrospective study, we included HCWs with severe disease for whom there were no hospital beds available at the time of evaluation. We provided daily assessments by infectious disease specialists, daily ambulatory steroid, oral thromboprophylaxis and domiciliary low-dose oxygen. We recorded the number of patients who recovered, were hospitalized or died on follow-up.

Results:

From 18 March 2020 to 16 July 2021, 1739 HCWs attended our service. A total of 540 were diagnosed with COVID-19. Seventy-four had severe COVID-19 and needed hospitalization. Immediate hospitalization was not possible in 56 patients who were sent to the OPAT and included in our study. Twenty-four patients subsequently required hospitalization and 32 recovered as outpatients.

Conclusions:

We describe a feasible and safe outpatient management strategy for HCWs with severe COVID-19 in a low-resource setting.

Life cycle of medical oxygen from production to consumption

Oxygen is used extensively in illnesses involving respiratory system. In emergencies such as the one created by the flare of Covid-19, oxygen consumption has increased tremendously. This article aims to improve our understanding about the medical oxygen, its production (air separation unit, pressure swing adsorption, oxygen concentrators), the supply chain, storage methods, and the final delivery system to the patient. This article also provides a comprehensive review on the additions in the medical infrastructure during the time of oxygen crisis in India along with the introduction of certain novel approaches towards oxygen production and conservation. We aim to minimize the panic among our readers by giving them an insight about the course behind the oxygen supply in that oxygen mask.

Patient's treatment burden related to care coordination in the field of respiratory diseases

The management of respiratory diseases requires various levels of care: multidisciplinary teams, educational and behavioural interventions, self-management and home-based technical support are vital to ensure adequate care management. However, it is often difficult to access these networks due to fragmentation of patient care and treatment burden. Care coordination aims to ensure patients have a central role and that there is continuity of care among various levels and professionals involved. Moreover, the coronavirus disease pandemic has caused strain on the global healthcare system, with care coordination becoming increasingly important in increasing the resilience of health systems, supporting healthcare professionals and ensuring the right treatment and adequate level of care for these patients.

[Guideline for Long-Term Oxygen Therapy - S2k-Guideline Published by the German Respiratory Society]

Long-term oxygen therapy is of great importance both for reducing mortality and for improving performance in patients with chronic lung diseases. The prerequisites for Long-term oxygen therapy are adequate diagnostics and clearly defined indication. A causal distinction into chronic hypoxaemic and hypercapnic respiratory failure is reasonable, from which the differential indication for non-invasive ventilation results.The revised guideline covers the diagnostics and indication of chronic lung and heart diseases, the role of oxygen in terminal illness and gives a detailed description of available oxygen devices. The guideline is intended to help avoid undersupply, oversupply and false prescriptions. Furthermore, the chapter "Postacute Oxygen Therapy" discusses the procedure, relevant in everyday life, but not yet clearly defined, for prescribing oxygen therapy for the home at the end of an inpatient stay. Another important point, the correct prescription of mobile oxygen systems, is also presented in the guideline. This document is a revised version of the guideline for longterm oxygen therapy and replaces the version of 2008.

Short Term Home Oxygen Therapy for COVID-19 patients: The COVID-HOT algorithm

Innovative solutions are required to effectively address the unprecedented surge of demand on our healthcare systems created by the COVID-19 pandemic. Home treatment and monitoring of patients who are asymptomatic or mildly symptomatic can be readily implemented to ameliorate the health system burden while maintaining safety and effectiveness of care. Such endeavor requires careful triage and coordination, telemedicine and technology support, workforce and education, as well as robust infrastructure. In the understandable paucity of evidence-based, protocolized approaches toward HOT for COVID-19 patients, our group has created the current document based on the cumulative experience of members of the Joint ACAIM-WACEM COVID-19 Clinical Management Taskforce. Utilizing available evidence-based resources and extensive front-line experience, the authors have suggested a pragmatic pathway for providing safe and effective home oxygen therapy in the community setting.

Contemporary portable oxygen concentrators and diverse breathing behaviours -- a bench comparison

Background

Decades of clinical research into pulsed oxygen delivery has shown variable efficacy between users, and across a user’s behaviours (sleep, rest, activity). Modern portable oxygen concentrators (POCs) have been shown as effective as other oxygen delivery devices in many circumstances. However, there are concerns that they are not effective during sleep when the breathing is shallow, and at very high respiratory rates as during physical exertion. It can be challenging to examine the determinants of POC efficacy clinically due to the heterogeneity of lung function within oxygen users, the diversity of user behaviour, and measurement issues. Representative bench testing may help identify key determinants of pulsed-oxygen device efficacy.

Methods

Three contemporary devices were bench-evaluated across three simulated breathing behaviours: activity, rest, & oronasal breathing during sleep. Emphasis was placed on breathing patterns representative of oxygen users.

Results

All three POCs performed well during simulated breathing during exertion and at rest. Differences in triggering ability were noted for the scenario of oronasal breathing during sleep.

Conclusions

The results are supportive of contemporary POC triggering abilities. The differences shown in ultimate trigger sensitivity may have relevance to oronasal breathing during sleep or other challenging scenarios for pulsed oxygen delivery, such as dominant mouth breathing during exertion or unfavourable nasal geometry.

Oxygen devices and delivery systems

Oxygen use has extended from inpatient to outpatient settings for patients with chronic pulmonary diseases and complications of hypoxaemia. This article presents an overview of oxygen devices (oxygen concentrators, compressed gas cylinders and liquid oxygen) and delivery systems (high- and low-flow). The indications, advantages and disadvantages of each device and delivery system are presented, aiming to offer updated knowledge to the multidisciplinary team members managing patients with respiratory failure, and therefore allowing appropriate selection of devices and delivery systems that are tailored to the needs of each patient.