Oxygen devices and delivery systems

Humidification during Invasive and Non-Invasive Ventilation: A Starting Tool Kit for Correct Setting

The humidification process of medical gases plays a crucial role in both invasive and non-invasive ventilation, aiming to mitigate the complications arising from bronchial dryness. While passive humidification systems (HME) and active humidification systems are prevalent in routine clinical practice, there is a pressing need for further evaluation of their significance. Additionally, there is often an incomplete understanding of the operational mechanisms of these devices. The current review explores the historical evolution of gas conditioning in clinical practice, from early prototypes to contemporary active and passive humidification systems. It also discusses the physiological principles underlying humidity regulation and provides practical guidance for optimizing humidification parameters in both invasive and non-invasive ventilation modalities. The aim of this review is to elucidate the intricate interplay between temperature, humidity, and patient comfort, emphasizing the importance of individualized approaches to gas conditioning.

Pulse versus non-pulse corticosteroid therapy in patients with acute exacerbation of idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

Corticosteroids are commonly used for the treatment of acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF); however, the optimal initial dose of corticosteroids remains uncertain due to a lack of sufficient evidence. We evaluated whether the administration of a pulse dose of corticosteroids resulted in improved survival outcomes compared with conventional non-pulse dose of corticosteroids.

METHODS

We retrospectively analysed 238 patients with AE-IPF treated with corticosteroids at a tertiary referral hospital between January 2013 and December 2021. Based on whether a pulse dose of corticosteroids (methylprednisolone of ≥250 mg/day or equivalent) was administered within 7 days of hospitalization for AE-IPF, the patients were divided into the pulse and non-pulse regimen groups. The survival outcomes were compared between the two groups using multivariable regression and propensity score-matched analyses.

RESULTS

Among the 238 patients, 59 patients received pulse dose of corticosteroids, whereas 179 patients received conventional non-pulse dose of corticosteroids. After adjusting for the confounding factors related to the baseline clinical and radiographic severity, compared with the conventional non-pulse regimen, the pulse regimen of corticosteroids did not reduce the risk of mortality at the 3-month (aHR 0.84, 95% CI 0.45-1.38) or 12-month (aHR 0.96, 95% CI 0.60-1.25) follow-ups. Propensity score-matched analysis revealed similar results.

CONCLUSION

The survival outcomes of patients with AE-IPF who received a pulse dose of corticosteroids did not differ from those of patients who received conventional non-pulse dose of corticosteroids. Further prospective studies are required to establish the optimal initial dose of corticosteroids for the treatment of AE-IPF.

The novel LESS (low-cost entrainment syringe system) O2 blender for use in modified bubble CPAP circuits: a clinical study of safety

Background

Bubble continuous positive airway pressure (bCPAP) is used in resource-limited settings for children with respiratory distress. Low-cost modifications of bCPAP use 100% oxygen and may cause morbidity from oxygen toxicity. We sought to test a novel constructible low-cost entrainment syringe system (LESS) oxygen blender with low-cost modified bCPAP in a relevant clinical setting.

Methods

We conducted a clinical trial evaluating safety of the LESS O2 blender among hospitalized children under five years old in rural Cambodia evaluating the rate of clinical failure within one hour of initiation of the LESS O2 blender and monitoring for any other blender-related complications.

Findings

Thirty-two patients were included. The primary outcome (clinical failure) occurred in one patient (3.1%, 95% CI = 0.1-16.2%). Clinical failure was defined as intubation, death, transfer to another hospital, or two of the following: oxygen saturation <85% after 30 min of treatment; new signs of respiratory distress; or partial pressure of carbon dioxide ≥60 mmHg and pH <7.2 on a capillary blood gas. Secondary outcomes included average generated FiO2's with blender use, which were 59% and 52% when a 5 mm entrainment was used vs. a 10 mm entrainment port with 5-7 cm H2O of CPAP and 1-7 L/min (LPM) of flow; and adverse events including loss of CPAP bubbling (64% of all adverse events), frequency of repair or adjustment (44%), replacement (25%), and median time of respiratory support (44 h).

Interpretation

Overall the LESS O2 blender was safe for clinical use. The design could be modified for improved performance including less repair needs and improved nasal interface, which requires modification for the blender to function more consistently.

Efficacy of Oxygen Treatment Using Home Oxygen Concentrators for the Treatment of Cluster Headaches: A Randomized, Crossover, Multicenter Study

BACKGROUND AND PURPOSE

Oxygen treatment is the first-line acute treatment for cluster headaches (CHs), but this can be impeded by insurance coverage and oxygen-tank maintenance. Oxygen concentrators filter nitrogen from ambient air to produce oxygen-rich gas, and can therefore be an alternative to conventional oxygen therapy using a tank. We investigated the effectiveness and safety of using two home oxygen concentrators and compared them with using oral zolmitriptan for the acute treatment of CHs.

METHODS

Forty patients with episodic CHs in an active cluster period were enrolled in this randomized, crossover, multicenter study. Two attacks during the cluster period were treated using oxygen delivered by connecting two home oxygen concentrators, whereas the other two attacks were treated using oral zolmitriptan (5 mg) in a random sequence. The primary endpoint was substantial pain reduction (0 or 1 on a five-point rating scale from 0 to 4 points) at 15 min after treatment.

RESULTS

In total, 125 attacks among 32 patients were randomized and treated (63 attacks using oxygen and 62 using zolmitriptan) according to the study protocol. More attacks treated using oxygen reached the primary endpoint than did those treated using zolmitriptan (31.7% [20/63] vs. 12.9% [8/62], p=0.013). After 30 min, 57.1% of the patients who received oxygen and 38.7% who received zolmitriptan reported pain relief (p=0.082). All patients treated using oxygen reported an improvement in pain, and 61.3% preferred oxygen while only 9.7% preferred zolmitriptan. No adverse events occurred during the oxygen treatment.

CONCLUSIONS

Oxygen treatment administered using two home oxygen concentrators resulted in better pain relief than oral zolmitriptan in patients with episodic CHs. Our results suggest that home oxygen concentrators are capable of efficiently supplying oxygen in a similar manner to using an oxygen tank.

Understanding the use of oxygen delivery devices

Many nurses will care for a patient who requires oxygen therapy, either to treat an acute respiratory condition, such as a lung infection, or a chronic condition, such as chronic obstructive pulmonary disease. This article discusses the physiology of gaseous exchange and provides an overview of some of the main respiratory conditions that may result in the need for oxygen therapy. The author also describes the oxygen delivery devices commonly used in clinical practice, such as simple face masks and nasal cannulas, to assist nurses in selecting the most appropriate device.

Glycerol-weighted chemical exchange saturation transfer nanoprobes allow 19F/1H dual-modality magnetic resonance imaging-guided cancer radiotherapy

Recently, radiotherapy (RT) has entered a new realm of precision cancer therapy with the introduction of magnetic resonance (MR) imaging guided radiotherapy systems into the clinic. Nonetheless, identifying an optimized radiotherapy time window (ORTW) is still critical for the best therapeutic efficacy of RT. Here we describe pH and O2 dual-sensitive, perfluorooctylbromide (PFOB)-based and glycerol-weighted chemical exchange saturation transfer (CEST) nano-molecular imaging probes (Gly-PFOBs) with dual fluorine and hydrogen proton based CEST MR imaging properties (19F/1H-CEST). Oxygenated Gly-PFOBs ameliorate tumor hypoxia and improve O2-dependent radiotherapy. Moreover, the pH and O2 dual-sensitive properties of Gly-PFOBs could be quantitatively, spatially, and temporally monitored by 19F/1H-CEST imaging to optimize ORTW. In this study, we describe the CEST signal characteristics exhibited by the glycerol components of Gly-PFOBs. The pH and O2 dual-sensitive Gly-PFOBs with19F/1H-CEST MR dual-modality imaging properties, with superior therapeutic efficacy and biosafety, are employed for sensitive imaging-guided lung cancer RT, illustrating the potential of multi-functional imaging to noninvasively monitor and enhance RT-integrated effectiveness.

Xylazine in the drug supply: Emerging threats and lessons learned in areas with high levels of adulteration

BACKGROUND

Xylazine, a sedative analgesic drug approved as an animal tranquilizer but not for human use, has become an adulterant in the illicit opioid marketplace in North America. Recently declared an emerging health threat in the U.S., the prevalence of xylazine in overdose deaths increased 5.5-fold between 2019 and 2021. More information is needed about the impact of xylazine on opioid users and harm reduction service providers.

METHODS

The impact of xylazine adulteration was triangulated through examination of (1) opioid overdose fatalities in Connecticut between 2017 and 2021 reported by the Office of the Chief Medical Examiner data, (2) a convenience survey of people in Connecticut who use drugs (PWUD) regarding their knowledge of and attitude about the local illicit drug supply, and (3) semi-structured interviews of harm reduction service providers in Connecticut and Philadelphia in response to prompts on the impacts of and responses to xylazine adulteration.

RESULTS

The presence of fentanyl or its analogues in fatal opioid overdoses was a statistically significant predictor of xylazine presence [OR = 25.0, 95%CI (10.7,81.1)] as was being Hispanic [OR = 1.36, 95%CI (1.03,1.77)]. A survey of people who used drugs revealed that 43% (n = 286) were concerned that the drug supply was always unpredictable. Three-quarters of respondents were aware of xylazine and two-thirds would use a xylazine test strip if one was available. Respondents who identified as White, Hispanic were most likely to be aware of xylazine, to have used a fentanyl test strip, and to be interested in a xylazine test strip. Respondents who injected drugs were 3.6-fold more likely than those who did not inject to endorse an interest in a xylazine test strip. Harm reduction service providers were cognizant of a range of problems surrounding the use and injection of xylazine. Although they reported implementing practices to better respond to xylazine harms, they recognized the absence of solutions to many of the problems encountered.

CONCLUSION

The prevalence of xylazine has expanded, especially in combination with fentanyl. Harm reduction education efforts with fidelity to best practices have emerged, but the harms persist and community prevention needs are largely unmet.

Effects of long-term oxygen therapy on the mental state of patients with chronic obstructive pulmonary disease: A systematic review

OBJECTIVES

This systematic review aimed to examine the effects of long-term oxygen therapy on the mental state of patients with chronic obstructive pulmonary disease.

METHODS

Web of Science, Medline, CINAHL, EMBASE, ProQuest, and Cochrane Library were selected to search for relevant studies. We followed the Cochrane Handbook for Systematic Reviews of Interventions, adopted the Cochrane risk-of-bias tool and Risk Of Bias In Non-randomized Studies of Interventions tool, and synthesized the outcomes narratively with Grading of Recommendations, Assessment, Development and Evaluations evidence profile.

RESULTS

Six studies were included. Moderate quality of evidence supported no effects of long-term oxygen therapy on the mental state in patients with severe resting hypoxemia and moderate resting hypoxemia (or exertional desaturation) at follow-up of 6 to 12 months; however, adverse effects on mental state among patients with moderate resting or exertional desaturation were reported at the follow-up of 36 to 48 months.

DISCUSSION

Nurses should focus on the mental state of patients treated with long-term oxygen therapy, especially those who use it for a prolonged time. Due to ethical constraints in this study, a quasi-experimental study with faithful consideration of internal validity can be commenced in the future.

Oxygen Therapy in COPD

Long-term oxygen therapy (LTOT) is a mainstay treatment for patients with severe resting hypoxemia secondary to chronic respiratory conditions including COPD. The evidence for LTOT is based on two trials that are now several decades old but have been insufficiently revisited. Therefore, many questions remain about precisely which patients experience the most benefit from LTOT, as well as how to define that benefit. Most studies have examined LTOT's effect on longevity rather than its impact on quality of life. In addition, many challenges exist in training both clinicians and patients on best practices for LTOT and associated equipment. Reimbursement policies have reduced the kinds of equipment available to the LTOT patient community, presenting additional challenges. This paper will review the current evidence for LTOT in COPD, the challenges involved with providing optimal therapy, and potential avenues of modernizing this essential intervention.

COVOX: Providing oxygen during the COVID-19 health emergency

We introduce an autonomous oxygen concentrator that was designed in Peru to fight the oxygen shortage produced worldwide as a consequence of the COVID-19 pandemic. Oxygen concentrators represent a suitable and favorable option for administering this gas at the patient's bedside in developing countries, especially when cylinders and tubed systems are unavailable or when access to them is restricted by lack of accessories, inadequate power supply, or shortage of qualified personnel. Our system uses a pressure swing adsorption technique to provide oxygen to patients at a flow rate of up to 15 l/min ± 1,5 l/min and a concentration of 93 % ± 3 %, offering robustness, safety and functionality. The quality measurements obtained from the validation process demonstrate repeatability and accuracy. The complete design files are provided in the source file repository to facilitate oxygen concentrator production in low and middle income countries, where access to oxygen is still a major problem even after the pandemic. Oxygen is part of the World Health Organization Model List of Essential Medicines and is perhaps the only medicine that has no substitute. This device can provide a reliable supply of oxygen for critically ill patients and improve their chances of survival.

Helmet CPAP in the emergency department: A narrative review

BACKGROUND

The choice of correct interface for the right patient is crucial for the success of non-invasive ventilation (NIV) therapy. Helmet CPAP is a type of interface used to deliver NIV. Helmet CPAP improves oxygenation by keeping the airway open throughout the breathing cycle with positive end-expiratory pressure (PEEP).

OBJECTIVE

This narrative review describes the technical aspects and clinical indications of helmet continuous positive airway pressure (CPAP). In addition, we explore the advantages and challenges faced using this device at the Emergency Department (ED).

DISCUSSION

Helmet CPAP is tolerable than other NIV interfaces, provides a good seal and has good airway stability. During Covid-19 pandemic, there are evidences it reduced the risk of aerosolization. The potential clinical benefit of helmet CPAP is demonstrated in acute cardiogenic pulmonary oedema (ACPO), Covid-19 pneumonia, immunocompromised patient, acute chest trauma and palliative patient. Compare to conventional oxygen therapy, helmet CPAP had been shown to reduce intubation rate and decrease mortality.

CONCLUSION

Helmet CPAP is one of the potential NIV interface in patients with acute respiratory failure presenting to the emergency department. It is better tolerated for prolonged usage, reduced intubation rate, improved respiratory parameters, and offers protection against aerosolization in infectious diseases.

Evaluation of the Effects of PAKDAM, an Invented Device to Get Nitrous Oxide and Oxygen, in the Consumers: A Report of Pilot Study

Background

Since last decade, a device called PAKDAM (means clean inspiration) was invented in Iran which has been used in some cafe to prepare N2O and O2 as a new instrument instead of using water pipe. This study aimed to evaluate the respiratory and health effects of Pakdam and investigate its short and midterm side effects in users.

Materials and Methods

In a case-control pilot study between September 2021 and March 2022, 152 individuals were divided into two groups: 76 consumers (case) and 76 non- consumers (control). Both groups were divided into two groups of 36 smokers and 36 non-smokers. Participants signed the participation form and filled out the demographic data questionnaire, and then their vital signs, O2 saturation, expiratory CO, and spirometry tests were recorded.

Results

The subjects who used the device had a mean blood pressure of 123.71±16.11 mmHg, oxygen saturation of 97.2±1.9, exhaled carbon monoxide of 9.8±5.5, and an FVC / FEV1 ratio of 88.5±7.9. These figures in control group were (137.79±18.15) - (94.1±4.2) - (14.3 ± 9.3) and (83.9 ± 10.4), respectively. In addition to the effects on the respiratory system, consumers had lower heart rates and lower systolic and diastolic blood pressures.

Conclusion

The blood oxygen level and FEV1/FVC ratio were higher in subjects using Pakdam and the amount of exhaled carbon monoxide and blood pressure were lower. This condition was more common in smokers and less in non-smokers. It is possible to see the favorable effects of using Pakdam device on people especially in smokers.

Clinical review of high-flow nasal oxygen therapy in human and veterinary patients

Oxygen therapy is the first-line treatment for hypoxemic acute respiratory failure. In veterinary medicine this has traditionally been provided via mask, low-flow nasal oxygen cannulas, oxygen cages and invasive positive pressure ventilation. Traditional non-invasive modalities are limited by the maximum flow rate and fraction of inspired oxygen (FiO₂) that can be delivered, variability in oxygen delivery and patient compliance. The invasive techniques are able to provide higher FiO₂ in a more predictable manner but are limited by sedation/anesthesia requirements, potential complications and cost. High-flow nasal oxygen therapy (HFNOT) represents an alternative to conventional oxygen therapy. This modality delivers heated and humidified medical gas at adjustable flow rates, up to 60 L/min, and FiO₂, up to 100%, via nasal cannulas. It has been proposed that HFNOT improves pulmonary mechanics and reduces respiratory fatigue via reduction of anatomical dead space, provision of low-level positive end-expiratory pressure (PEEP), provision of constant FiO₂ at rates corresponding to patient requirements and through improved patient tolerance. Investigations into the use of HFNOT in veterinary patients have increased in frequency since its clinical use was first reported in dogs with acute respiratory failure in 2016. Current indications in dogs include acute respiratory failure associated with pulmonary parenchymal disease, upper airway obstruction and carbon monoxide intoxication. The use of HFNOT has also been advocated in certain conditions in cats and foals. HFNOT is also being used with increasing frequency in the treatment of a widening range of conditions in humans. Although there remains conflict regarding its use and efficacy in some patient groups, overall these reports indicate that HFNOT decreases breathing frequency and work of breathing and reduces the need for escalation of respiratory support. In addition, they provide insight into potential future veterinary applications. Complications of HFNOT have been rarely reported in humans and animals. These are usually self-limiting and typically result in lower morbidity and mortality than those associated with invasive ventilation techniques.

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.

Design and Development of a Novel System for Remote Control of Stationary Oxygen Concentrator Flow Rate

Purpose

Long-term oxygen therapy involves utilizing stationary oxygen concentrators to allow patients with respiratory illnesses to attain sufficient blood oxygenation via supplemental oxygen. Disadvantages of these devices include their lack of remote adjustability and domiciliary accessibility. To adjust oxygen flow, patients typically walk across their homes - a physically taxing activity - to manually rotate the knob of the concentrator flowmeter. The purpose of this investigation was to develop a control system device that allows patients to remotely adjust the oxygen flow rates on their stationary oxygen concentrator.

Methods

The engineering design process was used to develop the novel FLO2 device. The two-part system is composed of 1) a smartphone application and 2) an adjustable concentrator attachment unit that mechanically interfaces with the stationary oxygen concentrator flowmeter.

Results

Product testing indicates that users successfully communicated to the concentrator attachment from a maximum distance of 41m in an open field, suggesting usability from anywhere inside a standard home. The calibration algorithm adjusted oxygen flow rates with an accuracy of ±0.019 LPM and a precision of ±0.042 LPM.

Conclusion

Initial design testing suggests the device as a reliable and accurate method of wirelessly adjusting oxygen flow on a stationary oxygen concentrator, but further testing should be performed on different stationary oxygen concentrator models.

2022 Brazilian Thoracic Association recommendations for long-term home oxygen therapy

Some chronic respiratory diseases can cause hypoxemia and, in such cases, long-term home oxygen therapy (LTOT) is indicated as a treatment option primarily to improve patient quality of life and life expectancy. Home oxygen has been used for more than 70 years, and support for LTOT is based on two studies from the 1980s that demonstrated that oxygen use improves survival in patients with COPD. There is evidence that LTOT has other beneficial effects such as improved cognitive function, improved exercise capacity, and reduced hospitalizations. LTOT is indicated in other respiratory diseases that cause hypoxemia, on the basis of the same criteria as those used for COPD. There has been an increase in the use of LTOT, probably because of increased life expectancy and a higher prevalence of chronic respiratory diseases, as well as greater availability of LTOT in the health care system. The first Brazilian Thoracic Association consensus statement on LTOT was published in 2000. Twenty-two years la-ter, we present this updated version. This document is a nonsystematic review of the literature, conducted by pulmonologists who evaluated scientific evidence and international guidelines on LTOT in the various diseases that cause hypoxemia and in specific situations (i.e., exercise, sleep, and air travel). These recommendations, produced with a view to clinical practice, contain several charts with information on indications for LTOT, oxygen sources, accessories, strategies for improved efficiency and effectiveness, and recommendations for the safe use of LTOT, as well as a LTOT prescribing model.

Photosynthetic microorganisms for the oxygenation of advanced 3D bioprinted tissues

3D bioprinting technology has emerged as a tool that promises to revolutionize the biomedical field, including tissue engineering and regeneration. Despite major technological advancements, several challenges remain to be solved before 3D bioprinted tissues could be fully translated from the bench to the bedside. As oxygen plays a key role in aerobic metabolism, which allows energy production in the mitochondria; as a consequence, the lack of tissue oxygenation is one of the main limitations of current bioprinted tissues and organs. In order to improve tissue oxygenation, recent approaches have been established for a broad range of clinical applications, with some already applied using 3D bioprinting technologies. Among them, the incorporation of photosynthetic microorganisms, such as microalgae and cyanobacteria, is a promising approach that has been recently explored to generate chimerical plant-animal tissues where, upon light exposure, oxygen can be produced and released in a localized and controlled manner. This review will briefly summarize the state-of-the-art approaches to improve tissue oxygenation, as well as studies describing the use of photosynthetic microorganisms in 3D bioprinting technologies. STATEMENT OF SIGNIFICANCE: 3D bioprinting technology has emerged as a tool for the generation of viable and functional tissues for direct in vitro and in vivo applications, including disease modeling, drug discovery and regenerative medicine. Despite the latest advancements in this field, suboptimal oxygen delivery to cells before, during and after the bioprinting process limits their viability within 3D bioprinted tissues. This review article first highlights state-of-the-art approaches used to improve oxygen delivery in bioengineered tissues to overcome this challenge. Then, it focuses on the emerging roles played by photosynthetic organisms as novel biomaterials for bioink generation. Finally, it provides considerations around current challenges and novel potential opportunities for their use in bioinks, by comparing latest published studies using algae for 3D bioprinting.

Systems on Top of Nasal Cannula Improve Oxygen Delivery in Patients with COVID-19: a Randomized Controlled Trial

BACKGROUND

Treating hypoxemia while meeting the soaring demands of oxygen can be a challenge during the COVID-19 pandemic.

OBJECTIVE

To determine the efficacy of the surgical facemask and the double-trunk mask on top of the low-flow oxygen nasal cannula on arterial partial pressure of oxygen (PaO2) in hypoxemic COVID-19 patients.

DESIGN

Randomized controlled trial.

PARTICIPANTS

Hospitalized adults with COVID-19 and hypoxemia treated with the low-flow nasal cannula were enrolled between November 13, 2020, and March 05, 2021.

INTERVENTIONS

Patients were randomized in a 1:1:1 ratio to receive either the nasal cannula alone (control) or the nasal cannula covered by the surgical facemask or the double-trunk mask. Arterial blood gases were collected at baseline and 30 min after the use of each system. The oxygen output was adapted afterwards to retrieve the baseline pulse oxygen saturation. The final oxygen output value was recorded after another 30-min period.

MAIN MEASURES

The primary outcome was the absolute change in PaO2. Secondary outcomes included changes in oxygen output, arterial partial pressure of carbon dioxide (PaCO2), vital parameters, and breathlessness.

KEY RESULTS

Arterial blood samples were successfully collected in 24/27 (8 per group) randomized patients. Compared to the nasal cannula alone, PaO2 increased with the surgical facemask (mean change: 20 mmHg, 95% CI: 0.7-38.8; P = .04) and with the double-trunk mask (mean change: 40 mmHg; 95% CI: 21-59; P < .001). Oxygen output was reduced when adding the surgical facemask (median reduction: 1.5 L/min [95% CI: 0.5-4.5], P < .001) or the double-trunk mask (median reduction: 3.3 L/min [95% CI: 2-5], P < .001). The double-trunk mask was associated with a PaCO2 increase of 2.4 mmHg ([95% CI: 0-4.7], P = .049). Neither mask influenced vital parameters or breathlessness.

CONCLUSIONS

The addition of the surgical facemask or the double-trunk mask above the nasal cannula improves arterial oxygenation and reduces oxygen consumption.

A comparison of high-flow nasal cannula and standard facemask as pre-oxygenation technique for general anesthesia: A PRISMA-compliant systemic review and meta-analysis

BACKGROUND

Current practice guidelines recommend the use of nasal cannula as an alternative pre-oxygenation method for tracheal intubation. However, the efficacy of high-flow nasal oxygenation versus standard facemask oxygenation has not been fully evaluated.

METHODS

We searched PubMed, Cochrane Library, and ClinicalTrials.gov for English-language studies published from January 1, 2000 to November 30, 2021. We included randomized controlled trials which compared high-flow nasal oxygenation and facemask oxygenation as the pre-oxygenation maneuver. Primary outcome was arterial partial pressure of oxygen (PaO2) after pre-oxygenation. Secondary outcomes were safe apnea time, arterial desaturation during intubation, lowest peripheral capillary oxygen saturation during intubation, and patient comfort score. Random-effects models and Mantel-Haenszel method were used for data synthesis.

RESULTS

A total of 16 randomized controlled trials and 1148 patients were included. High-flow nasal oxygenation achieved a higher PaO2 compared with facemask, mean difference: 64.86 mm Hg (95% confidence interval [CI]: 32.33-97.40, P < .0001). Safe apnea time was longer in high-flow nasal oxygenation, mean difference: 131.03 seconds (95% CI: 59.39-202.66, P < .0001). There was no difference in the risk of peri-intubation desaturation or lowest peripheral capillary oxygen saturation between groups. Patient comfort score was higher in high-flow nasal oxygenation, mean difference: 1.00 (95% CI: 0.46-1.54, P = .0003).

CONCLUSION

High-flow nasal oxygenation better enhanced PaO2 and extended safe apnea time and is not inferior to facemask oxygenation in preventing desaturation during tracheal intubation. High-flow nasal oxygenation may be considered as an alternative method, especially for patients with a potential difficult airway.

Performance of Different Low-Flow Oxygen Delivery Systems

BACKGROUND

The delivery of a high and consistent [Formula: see text] is imperative to treat acute hypoxemia. The objective of this study was to analyze the effective inspired oxygen concentration delivered by different low-flow oxygen therapy systems challenged with different oxygen flows and respiratory patterns in an experimental lung model.

METHODS

An adult lung model ventilated in volume control mode simulated different respiratory patterns to obtain mean inspiratory flow of 22.5, 30.0, 37.5, or 45.0 L/min. The oxygen concentration sampled inside the lung model by nasal cannula, simple face mask, non-rebreather mask, and double-trunk mask above nasal cannula tested at oxygen flows of 10, 12.5, and 15 L/min was quantified. The 3 masks were sealed tight onto the model's airway opening. They were also tested with standardized leaks to determine their clinical performance.

RESULTS

All oxygen delivery systems delivered higher oxygen concentration with increasing oxygen flows, regardless of the respiratory pattern. Within each device, the increase in inspiratory flow decreased oxygen concentration when using nasal cannula (P = .03), the simple face mask (P = .03), but not the non-rebreather mask (P = .051) nor the double-trunk mask (P = .13). In sealed condition, the double-trunk mask outperformed the non-rebreather mask and simple face mask (P < .001); mean oxygen concentration was 84.2%, 68.5%, and 60.8%, respectively. Leaks amplified oxygen concentration differences between the double-trunk mask and the other masks as the oxygen delivery decreased by 4.6% with simple face mask (95% CI 3.1-6.1%, P < .001), 7.8% with non-rebreather mask (95% CI 6.3-9.3%, P < .001), and 2.5% with double-trunk mask (95% CI 1-4%, P = .002). With leaks, the oxygen concentration provided by the simple face mask and the non-rebreather mask was similar (P = .15).

CONCLUSIONS

Lung oxygen concentration values delivered by the double-trunk mask were higher than those obtained with other oxygen delivery systems, especially when leaks were present.

High-Flow-Sauerstofftherapie – Chancen und Risiken

Mit der High-Flow-Sauerstofftherapie („high flow nasal cannula“ [HFNC]), bei der ein Sauerstoff-Luft-Gasgemisch mit Flüssen zwischen 30 und 70 l/min appliziert wird, steht ein technisch einfaches und hocheffektives Verfahren zur Therapie einer respiratorischen Insuffizienz zur Verfügung. Des Weiteren kann die HFNC während einer Bronchoskopie zur Oxygenierung, vor einer Intubation zur Präoxygenierung und nach Extubation zur Vermeidung einer Re-Intubation verwendet werden. Durch die hohen Gasflüsse wird vermieden, dass der Patient Umgebungsluft inspiriert, sodass eine präzise Einstellung einer inspiratorischen Sauerstofffraktion möglich ist, des Weiteren wird durch einen entstehenden Staudruck ein positiver endexspiratorischer Druck aufgebaut, durch die Anfeuchtung und Erwärmung der Atemluft die mukoziliäre Clearance verbessert sowie die Atemarbeit durch Auswaschen der oberen Atemwege verringert. Im Vergleich zur konventionellen Sauerstofftherapie ist die Aerosolbildung durch eine HFNC nicht erhöht, sodass dieses Verfahren auch bei COVID-19 eingesetzt werden kann. Beim hyperkapnischen Lungenversagen liegen bisher keine konklusiven Daten für die Effekte der HFNC vor, hier sollte bevorzugt eine nichtinvasive Beatmung statt einer HFNC erfolgen. Bei der Anwendung darf nicht vergessen werden, dass die mit HFNC behandelten Patienten kritisch krank sind und daher kontinuierlich überwacht werden müssen. So muss sichergestellt sein, dass jederzeit eine Eskalation z. B. auf eine Intubation und invasive Beatmung erfolgen kann.

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.

The effect of transnasal humidified rapid-insufflation ventilator exchange (THRIVE) versus nasal prongs on safe apnoea time in paralysed obese patients: a randomised controlled trial

BACKGROUND

Evidence is lacking regarding the efficacy of Optiflow transnasal humidified rapid-insufflation ventilator exchange (THRIVE™) in obese patients. We compared the impact of this technique at 70 L min^-1 with 4 L min^-1 oxygen via nasal prongs on safe apnoea times of paralysed obese patients.

METHODS

We randomised adults with a BMI >35 kg m^-2 undergoing elective bariatric surgery. While apnoeic and paralysed, Group T received 70 L min^-1 oxygen via Optiflow THRIVE™. Group N received nasal prong oxygen at 4 L min^-1. The primary outcome was time to SpO₂ ≤95% while apnoeic, with a 360 s cut-off. This was analysed by applying a time-to-event analysis.

RESULTS

Forty-two patients were included. The median (inter-quartile range) BMI was 44.8 kg m^-2 (40.0-50.0) in Group T and 42.0 kg m^-2 (39.3-45.1) in Group N. Median (inter-quartile range) time to SpO₂ ≤95% in Group T was 356 (165 to ≥360) s and in Group N, 210 (160-270) s. Using a survival analysis framework, median time-to-event in Group T was 356 s (95% confidence interval 165 s-upper limit not defined) and 210 s (95% confidence interval 160-242 s) (P=0.049) in Group N.

CONCLUSIONS

Compared with oxygen delivered via nasal prongs at 4 L min^-1, oxygen delivery via Optiflow THRIVE™ at a flow rate of 70 L min^-1 can prolong safe apnoea time, however, the results are statistically inconclusive. Optiflow THRIVE™ did decrease the rate of reduction in Pa_o2 during apnoea.

CLINICAL TRIAL REGISTRATION

ANZCTR 12618000445279.

Normobaric oxygen treatment for mild-to-moderate depression: a randomized, double-blind, proof-of-concept trial

Oxygen enriched air may increase oxygen pressure in brain tissue and have biochemical effects even in subjects without lung disease. Consistently, several studies demonstrated that normobaric oxygen treatment has clinical benefits in some neurological conditions. This study examined the efficacy of normobaric oxygen treatment in subjects with depression. In a randomized, double-blind trial, 55 participants aged 18-65 years with mild to moderate depression (had a Hamilton Rating Scale for Depression [HRSD] score of ≥ 8) were recruited to the study from the Southern district in Israel. Participants underwent a psychiatric inclusion assessment at baseline and then were randomly assigned to either normobaric oxygen treatment of 35% fraction of inspired oxygen or 21% fraction of inspired oxygen (room air) through a nasal tube, for 4 weeks, during the night. Evaluations were performed at baseline, 2 and 4 weeks after commencement of study interventions, using the following tools: HRSD; Clinical Global Impression (CGI) questionnaire; World Health Organization-5 questionnaire for the estimation of Quality of Life (WHO-5-QOL); Sense of Coherence (SOC) 13-item questionnaire; and, Sheehan Disability Scale (SDS). A multivariate regression analysis showed that the mean ± standard deviation [SD] changes in the HRSD scores from baseline to week four were - 4.2 ± 0.3 points in the oxygen-treated group and - 0.7 ± 0.6 in the control group, for a between-group difference of 3.5 points (95% confidence interval [CI] - 5.95 to - 1.0; P = 0.007). Similarly, at week four there was a between-group difference of 0.71 points in the CGI score (95% CI - 1.00 to - 0.29; P = 0.001). On the other hand, the analysis revealed that there were no significant differences in WHO-5-QOL, SOC-13 or SDS scores between the groups. This study showed a significant beneficial effect of oxygen treatment on some symptoms of depression.Trial registration: NCT02149563 (29/05/2014).

Basic Airway Management for the Professional Nurse

The registered nurse (RN) on a medical-surgical nursing unit may be the first health care professional to encounter a patient with the signs of impending respiratory failure. Importantly, the RN must recognize the signs of respiratory compromise and possess the competence and confidence to intervene without delay. Signs of respiratory deterioration, physical assessment, and respiratory laboratory studies are reviewed. Modes of oxygen therapy, basic airway management techniques, including bag mask ventilation, and use of oropharyngeal and nasopharyngeal airways are discussed. The assembly of equipment and medications frequently used for intubation are also outlined.

Oxygen and Ventilator Logistics During California's COVID-19 Surge: When Oxygen Becomes a Scarce Resource

The state of California, in the United States of America, has a population of nearly 40 million people and is the 5th largest economy in the world. During the coronavirus disease 2019 (COVID-19) pandemic in 2020-2021, the state experienced a medical surge that stressed its sophisticated health-care and public health system. During this period, ventilators, oxygen, and other equipment necessary for providing ventilatory support became a scarce resource in many health-care settings. When demand overwhelms supply, creative solutions are required at all levels of disaster management and health care. This study describes the disaster response by the state of California to mitigate the emergency demands for oxygen delivery resources.

Characteristics and predictors for silent hypoxemia in a cohort of hospitalized COVID-19 patients

Background

An intriguing feature recently unveiled in some COVID-19 patients is the “silent hypoxemia” phenomenon, which refers to the discrepancy of subjective well-being sensation while suffering hypoxia, manifested as the absence of dyspnea.

Objective

To describe the clinical characteristics and predictors of silent hypoxemia in hospitalized COVID-19 patients.

Methods

We conducted a prospective cohort study including consecutive hospitalized adult (≥ 18 years) patients with confirmed COVID-19 presenting to the emergency department with oxygen saturation (SpO2) ≤ 80% on room air from March 15 to June 30, 2020. We analyzed the characteristics, disease severity, and in-hospital outcomes of patients presenting with dyspnea and those without dyspnea (silent hypoxemia).

Results

We studied 470 cases (64.4% men; median age 55 years, interquartile range 46–64). There were 447 (95.1%) patients with dyspnea and 23 (4.9%) with silent hypoxemia. The demographic and clinical characteristics, comorbidities, laboratory and imaging findings, disease severity, and outcomes were similar between groups. Higher breathing and heart rates correlated significantly with lower SpO₂ in patients with dyspnea but not in those with silent hypoxemia. Independent predictors of silent hypoxemia were the presence of new-onset headache (OR 2.919, 95% CI 1.101–7.742; P = 0.031) and presenting to the emergency department within the first eight days after symptoms onset (OR 3.183, 95% CI 1.024–9.89; P = 0.045).

Conclusions

Patients with silent hypoxemia sought medical attention earlier and had new-onset headache more often. They were also likely to display lower hemodynamic compensatory responses to hypoxemia, which may underestimate the disease severity.

Protocol for assessing and predicting acute respiratory decline in hospitalized patients

This protocol aids both new and experienced researchers in designing retrospective clinical and translational studies of acute respiratory decline in hospitalized patients. This protocol addresses (1) the basics of respiratory failure and electronic health record research, (2) defining patient cohorts as "mild, progressive, or severe" instead of "ICU versus non-ICU", (3) adapting physiological indices, and (4) using biomarker trends. We apply these approaches to inflammatory biomarkers in COVID-19, but this protocol can be applied to any progressive respiratory failure study. For complete details on the use and execution of this protocol, please refer to Mueller et al. (2020).

Community distribution of oxygen: a unique COVID-19 intervention

The rapid spread of COVID-19 around the world has exposed some long-standing deficiencies in health systems, particularly in environments with low financial and medical resources. Most patients ill with COVID-19 require oxygen and supportive therapy for survival as there remains no conclusively established curative therapy. Following a number of critical research work and drawing from a millennia-long evolution of medical practice, respiratory support has been identified as a paramount intervention to ensure lives are saved when supportive care is required, and oxygen is an essential commodity to achieve this. This letter focuses on the numerous means for oxygen delivery to health facilities and in turn the end users and expands on the importance of innovation to improve oxygen supply. We describe a community distribution system with a telemedicine structure that can be leveraged for oxygen delivery.

Application of Radiosensitizers in Cancer Radiotherapy

Radiotherapy (RT) is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. Although great success has been achieved on radiotherapy, there is still an intractable challenge to enhance radiation damage to tumor tissue and reduce side effects to healthy tissue. Radiosensitizers are chemicals or pharmaceutical agents that can enhance the killing effect on tumor cells by accelerating DNA damage and producing free radicals indirectly. In most cases, radiosensitizers have less effect on normal tissues. In recent years, several strategies have been exploited to develop radiosensitizers that are highly effective and have low toxicity. In this review, we first summarized the applications of radiosensitizers including small molecules, macromolecules, and nanomaterials, especially those that have been used in clinical trials. Second, the development states of radiosensitizers and the possible mechanisms to improve radiosensitizers sensibility are reviewed. Third, the challenges and prospects for clinical translation of radiosensitizers in oncotherapy are presented.

[Oxygen therapy in emergency and intensive care medicine]

Oxygen treatment is being widely used in intensive care and emergency medicine and is required to maintain aerobic metabolism. It may be administered by nasal cannula, face mask, high-flow therapy, and by ventilation. Under clinical circumstances, blood oxygen concentration is not relevantly increased above a partial pressure of 80 mmHg. Although oxygen therapy is often life-saving, it has recently been shown that its indiscriminate administration may increase morbidity and mortality, presumably due to a formation of reactive-oxygen species.For ventilated critically ill patients the optimal targets need to be further defined but harm has been shown for mild hyperoxia. For patients with acute exacerbation of chronic obstructive lung disease hyperoxia may lead to an increase of hypercarbia. Hyperoxia may increase myocardial necrosis in myocardial infarction. For patients with stroke, data do not show any benefit or harm from oxygen administration.On the other hand, hyperoxia shall be used for treatment in patients with cardiac arrest until return of spontaneous circulation and in patients with carbon monoxide poisoning.For other conditions, no benefit has been shown for hyperoxia, but undoubtedly, hypoxemia must be avoided, as well. Therefore, a normoxic oxygenation strategy should be employed. The optimal oxygenation targets for distinct conditions need to be further defined.