Oxygen Delivery Devices Research Articles

Performance of a new oxygen delivery device for potentially infectious critically ill patients

In patients with highly contagious diseases that are spread by respiratory droplets or air-borne particles, the use of high-flow oxygen may carry a significant risk of nosocomial transmission. We tested a new oxygen delivery device designed to address these problems by simulating 108 patients with sepsis and respiratory failure. The device being tested consisted of an airtight mask, a bacterial and viral filter, a T-shaped reservoir (50 and 100 ml) and oxygen delivery tubing connected directly to the mask. When tested with a 50-ml reservoir, a high fractional oxygen concentration was achieved: mean (SD) 0.83 (0.11) at a flow of 15 l.min(-1) oxygen. The 50-ml reservoir, when compared with the 100-ml reservoir, was associated with reduced carbon dioxide rebreathing (mean (SD) inspired fractional carbon dioxide concentration 2.5 (1.0) vs 3.0 (1.1), respectively, p = 0.009) and reduced inspiratory resistive work of breathing (mean (SD) 1.0 (0.6) J.l(-1) vs 1.2 (0.5) J.l(-1), respectively, p = 0.028). However, rebreathing and work of breathing were relatively high if a high respiratory rate was simulated. We conclude that the novel oxygen device we describe, equipped with the 50-ml T-shaped reservoir, is suitable for potentially infectious patients with type-1 respiratory failure but without marked tachypnoea.

Long-term oxygen therapy

Long-term oxygen therapy (LTOT) has been shown to reduce pulmonary hypertension and improve survival in patients with chronic obstructive pulmonary disease and resting hypoxemia (reduced arterial partial pressure of oxygen ≤55 mmHg). However, the benefit of its use for chronic pulmonary diseases other than chronic obstructive pulmonary disease as well as for nonpulmonary conditions is debatable. Its role in patients with mild hypoxemia (reduced arterial partial pressure of oxygen >55 mmHg at rest) is presently being investigated in the LOTT. A meta-analysis of four controlled trials reporting the role of LTOT in patients with either nocturnal desaturation or daytime moderate hypoxemia found no difference in survival between patients on LTOT than those without. Advances in oxygen delivery and conservation devices have made domiciliary oxygen therapy more practical and popular for patients. There still remain concerns with the actual compliance of therapy among the needy patients.

Descriptive analysis of emergency department oxygen use in acute exacerbation of chronic obstructive pulmonary disease

Inconsistencies in oxygen therapy recommendations in acute exacerbation of chronic obstructive pulmonary disease (COPD) may result in variability in emergency department (ED) oxygen management of patients with COPD. The aim of this study was to describe oxygen management in the first 4 h of ED care for patients with exacerbation of COPD. A retrospective medical record audit was conducted at four public and one private ED in Melbourne, Australia. Participants were 273 adult ED patients with COPD presenting with a primary complaint of shortness of breath from July 2006 to July 2007. Outcome measures were physiological data, including oxygen saturation (SpO(2)), oxygen delivery devices and flow rates on ED arrival, 1 and 4 h. Oxygen was used in 82.0% of patients. Patients who required oxygen had higher incidence of ambulance transport (P < 0.001), triage category 2 (P = 0.006), home oxygen use (P < 0.001), and increased work of breathing on ED arrival (P < 0.001), and higher median respiratory rate (P < 0.001) and heart rate (P = 0.001). SpO(2) > 90% occurred in the majority of patients (87.5%; 96.4%; 95.6%); however, a considerable number of patients with SpO(2) < 90% were not given oxygen (61.8%; 30%; 45.5%). A number of patients with documented hypoxaemia were not given oxygen and there may be variables other than oxygen saturation that may influence oxygen use. Future research should focus on increasing the evidence-based supporting oxygen use and better understanding of clinicians' oxygen decision-making in patients with COPD.

Ralstonia mannitolilyticaand COPD: a case report

To the Editors: Ralstonia mannitolilytica is a recently established species of clinical significance and was previously known as Pseudomonas thomasii or Ralstonia pickettii biovar 3/ thomasii [1]. It has been recovered from the respiratory tract of patients with cystic fibrosis and has also been associated with catheter-associated bacteraemia, recurrent meningitis, infection of a haemoperitoneum, urinary tract infection and post-renal transplant infection. Hospital outbreaks of R. mannitolilytica due to contamination of water [2], saline solutions [3] or oxygen-delivery devices [4] have also been reported. However, this bacterium has not been reported in patients with respiratory illnesses other than cystic fibrosis. Isolate G100 was recovered from a sputum sample from a male, 78-yr-old patient in April, 2010. This patient was presented with cough and gradually worsening dyspnoea for 1 month, but without fever. He received no antimicrobial agents prior to admission. This patient had a 20-yr history of intermittent cough, and chronic obstructive pulmonary disease (COPD) was diagnosed 10 yrs previously. He had also had type II diabetes mellitus for 5 yrs and had been a cigarette smoker for >20 yrs, but had stopped smoking 10 yrs previously. Physical examination revealed a “barrel-shaped” chest, reduced breath sounds and crackles. On admission, a full …

Humidified High-Flow Nasal Oxygen Utilization in Patients with Cancer at Memorial Sloan-Kettering Cancer Center

Respiratory signs and symptoms are commonly encountered by physicians who care for cancer patients. Supplemental oxygen (SOx) has long been used for treatment of hypoxic respiratory insufficiency, but data reveal mixed efficacy results. The use and outcome patterns of technologically advanced oxygen delivery devices, such as humidified high-flow nasal oxygen (HHFNOx), are incompletely understood. Institutional database search of the number of patient cases in which the current HHFNOx device was used, and abstraction of 183 patient medical records for usage characteristics. Patients have been treated with HHFNOx at Memorial Sloan Kettering Cancer Center (MSKCC) since 2008. Of the 183 patients randomly selected for our study, 72% received HHFNOx in the intensive care unit (ICU) because of hypoxia. Patients usually improved (41%) or remained stable (44%) while on the device, whereas 15% declined. At study completion, 45% of patients were living, and 55% had died. The median time on HHFNOx was 3 days (range: 1-27). A do not resuscitate (DNR) order was present in 101 (55%) patients, either before (12%) or after (43%) device utilization. The majority (78%) of these 101 patients died at MSKCC. Dyspnea is a common and important symptom in cancer patients for which SOx traditionally has had no clear basis except in select cases of hypoxia and patient preference. Our institutional experience with HHFNOx contributes to the understanding of the applications and challenges surrounding the use of new medical devices in the cancer population. Physiologic and quality-of-life benefits of HHFNOx compared with traditional oxygen delivery methods should be studied prospectively.

A measurement setup for direct 17O MRI at 7 T

An efficient breathing system was designed for direct (17)O MRI to perform oxygen metabolism studies of the human brain. The breathing system consists of a demand oxygen delivery device for (17)O(2) supply and a custom-built re-breathing circuit with pneumatic switching valve. To efficiently deliver the (17)O gas to the alveoli of the lungs, the system applies short gas pulses upon an inspiration trigger via a nasal cannula. During and after (17)O(2) administration, the exhaled gas volumes are stored and filtered in the re-breathing section to make the most efficient use of the rare (17)O gas. In an inhalation experiment, 2.2 ± 0.1 L of 70%-enriched (17)O(2) were administered to a healthy volunteer and direct (17)O MRI was performed for a total imaging time of 38 min with a temporal resolution of 50 s per 3D data set. Mapping of the maximum signal increase was carried out showing regional variations of oxygen concentration of up to 30% over the natural abundance of (17)O water.

A simple, innovative way to reduce rhinitis symptoms after sedation during endoscopy.

Supplmental oxygen is routinely given via nasal cannula (NC) to patients undergoing moderate sedation for endoscopy. Some patients complain of profuse rhinorrhea and⁄or sneezing after the procedure, which results in additional medical costs and patient dissatisfaction. To determine the causal relationship between the route of oxygen delivery and troublesome nasal symptoms, and to seek possible solutions. Patients (n=836) were randomly assigned to one of the three following groups: the NC group (n=294), the trimmed NC (TNC) group (n=268) and the nasal mask (NM) group (n=274). All received alfentanil 12.5 μg⁄kg and midazolam 0.06 mg⁄kg, and adjunct propofol for sedation. Supplemental oxygen at a flow rate of 4 L⁄min was used in the NC and TNC groups, and 6 L⁄min in the NM group. The incidence of nasal symptoms and hypoxia were assessed. The incidence of rhinitis symptoms was significantly higher in the NC group (7.1%) than in the TNC (0.4%) and NM (0%) groups (P<0.001). The incidence of hypoxia was lower in the NC group (3.1%) (P=0.040). All hypoxia events were transient (ie, less than 30 s in duration). On spirometry, the mean value of the lowest saturation of peripheral oxygen was found to be significantly lower in the NM group (96.8%) than in the NC group (97.7%) (P=0.004). Trimming the NC or using NMs reduced the incidence of rhinitis symptoms; however, the incidence of hypoxia was higher. Further investigation regarding the efficiency of oxygen supplementation is warranted in the design of novel oxygen delivery devices.

Knowledge of oxygen delivery among paediatric trainee doctors and experienced paediatric nurses

Aims Assess the knowledge of oxygen delivery among paediatric junior doctors and nurses. Methods A paper survey was developed, piloted, refined and completed by junior doctors at induction to a children9s hospital, and experienced paediatric nurses attending post registration courses. The purpose was to identify and direct address knowledge gaps. Respondents needed to identify various oxygen delivery devices (nasal cannulae, face mask, face mask and reservoir bag, head box, tracheostomy mask, bag-valve-mask (BVM) and Ayre9s T-piece), specify maximum percentage (%) of oxygen that can be delivered, flow rates required, use with spontaneously breathing patients and possibility of delivering continuous positive airway pressure. Results A total of 152 surveys were completed, 29 of these by nurses. Identification: Nasal cannulae, tracheostomy mask and BVM were correctly identified 98%, 89% and 94% of the time. There was confusion over headbox (63% correct), face mask and reservoir bag (22% correct) and Ayre9s t-piece (36% correct). Knowledge of maximum % oxygen delivered by each device was poor: nasal cannulae had 28% (32/114) correct answers; 42/114 responded that nasal cannulae delivered >40% oxygen. BVM and Ayre9s T-piece had the most correct answers (69% and 82%). Flow rate responses showed poor knowledge of carbon dioxide clearance with oxygen delivery: 30% (37/125) would give Conclusion There are significant knowledge gaps regarding oxygen therapy despite their frequent use. Maximum % oxygen delivery and flow rates were particularly poor, with potential negative impact on patient care including: delivering too little oxygen in emergencies with BVM and face masks and reservoir, or too low flow rates with face masks and head boxes leading to CO 2 retention. The correct use of BVM requires particular clarification. This survey informed interactive teaching focusing on this common, important and life-saving therapy.

Getting inspired about oxygen delivery devices

Learn the ins and outs of supplemental oxygen therapy, including which delivery device is best for your patient.

Exhaled Air and Aerosolized Droplet Dispersion During Application of a Jet Nebulizer

BackgroundAs part of our influenza pandemic preparedness, we studied the dispersion distances of exhaled air and aerosolized droplets during application of a jet nebulizer to a human patient simulator (HPS) programmed at normal lung condition and different severities of lung injury.MethodsThe experiments were conducted in a hospital isolation room with a pressure of − 5 Pa. Airflow was marked with intrapulmonary smoke. The jet nebulizer was driven by air at a constant flow rate of 6 L/min, with the mask reservoir filled with sterile water and attached to the HPS via a nebulizer mask. The exhaled leakage jet plume was revealed by a laser light sheet and images captured by high-definition video. Smoke concentration in the plume was estimated from the light scattered by smoke and droplet particles.FindingsThe maximum dispersion distance of smoke particles through the nebulizer side vent was 0.45 m lateral to the HPS at normal lung condition (oxygen consumption, 200 mL/min; lung compliance, 70 mL/cm H2O), but it increased to 0.54 m in mild lung injury (oxygen consumption, 300 mL/min; lung compliance, 35 mL/cm H2O), and beyond 0.8 m in severe lung injury (oxygen consumption, 500 mL/min; lung compliance, 10 mL/cm H2O). More extensive leakage through the side vents of the nebulizer mask was noted with more severe lung injury.InterpretationHealth-care workers should take extra protective precaution within at least 0.8 m from patients with febrile respiratory illness of unknown etiology receiving treatment via a jet nebulizer even in an isolation room with negative pressure.

Transdermal Oxygen Delivery to Diabetic Wounds

To evaluate the use of a transdermal sustained oxygen delivery system to promote the healing of chronic lower extremity wounds in patients with diabetes. Six patients (5 men, 1 woman; age range, 32-77 years) with diabetes and chronic lower extremity wounds unresponsive to previous multimodal therapy were treated with transdermal sustained oxygen. The transdermal sustained oxygen delivery device (EpiFLO; Ogenix Corp, Cleveland, Ohio) delivered 100% oxygen at 3 mL/h with ambient humidity, 24 h/day, directly to the wound site, which was covered by an occlusive dressing. Despite chronicity of wounds (aged 4 months to >15 years) and nonresponsiveness to previous treatments, all wounds in this case series treated with transdermal sustained oxygen therapy improved within 2 to 20 weeks, within which time 5 of the 6 wounds had healed completely. In 2 cases, scheduled amputations were prevented. The results of the 6 cases reported here strongly support the use of transdermal sustained oxygen therapy in promoting the healing of diabetic foot and leg ulcers refractory to previous treatments. In addition, amputation was prevented in 2 cases, thus reducing prolonged costly patient care.

Characterization of sterilization techniques on a microfluidic oxygen delivery device

A microfluidic oxygen delivery device was designed to regulate the exposure of cells in culture to oxygen, facilitating experiments involving oxygen-dependent cell processes. Most of the device is composed of the biocompatible elastomer PDMS (polydimethylsiloxane), including the thin gas-permeable membrane which serves as a diffusive interface between a flowing gas source and the cell culture media. Because cell cultures require a sterile environment, the device must be sterile as well. This study was designed to investigate the effects of common sterilization techniques on the diffusive properties of the device. Devices were sterilized repetitively with autoclaving, UV light, Dri-Clean detergent soaks, or ethanol soaks. Diffusion of oxygen across the device membranes was periodically measured using fluorescent microscopy. After 32 treatments no significant changes were seen in oxygen diffusion over time or in sterilization groups compared to control, meaning that the utility of the device is not adversely affected by repetitive sterilization.

High-flow humidified oxygen therapy used to alleviate respiratory distress

This article describes the utilization of humidified high-flow oxygen therapy systems, which can comfortably deliver optimal humidified high-flow oxygen therapy, via nasal cannulae, at flow rates of up to 40 litres per minute to adult patients, in hospital or at home. The oxygen is saturated with water vapour at body temperature allowing flow to be well tolerated. First, to set the scene, three clinical scenarios are presented of patients nursed in intensive care, who suffered severe respiratory distress. Respiratory failure is explained, and the need for oxygen therapy set out. Alternative oxygen delivery devices and systems are then outlined, and an example of a high-flow system introduced. Set-up of the system is explained and the need for decontamination propounded. Finally, the benefits of the humidified high-flow oxygen system are exemplified, with particular reference to the critically ill patients presented here.

Evaluation of Nasopharyngeal Oxygen, Nasal Prongs and Facemask Oxygen Therapy Devices in Adult Patients: A Randomised Crossover Trial

Nasopharyngeal oxygen (NPO) therapy may overcome some of the difficulties associated with nasal prongs and facemask oxygen delivery devices. In response to a lack of published studies of NPO therapy in adults, we conducted a prospective randomised crossover trial to compare the effectiveness of NPO, nasal prongs (NP) and facemasks (FM) when used in an adult population (n = 37) from the intensive care unit and general hospital wards. We measured oxygen saturation (SpO2) using pulse oximetry, oxygen flow (litres per minute), respiration rate (per minute) and comfort using a horizontal visual analogue scale. All three devices were effective in maintaining a SpO2 of > or = 95% (NP 97.0 +/- 1.9, NPO 97.7 +/- 1.7, FM 98.8 +/- 1.3%). NPO therapy consumed less oxygen than NP and FM therapy (NP 2.6 +/- 1.0, NPO 2.2 +/- 0.9, FM 6.1 +/- 0.4 l/min, P < 0.001). There was no significant difference in patients' respiratory rates (NP 19.9 +/- 3.2, NPO 19.9 +/- 3.0, FM 19.8 +/- 3.1 per minute, P = 0.491). In terms of comfort, patients rated NP higher than NPO and FM using a horizontal visual analogue scale (100 mm = most comfortable) (NP 65.5 +/- 14.3, NPO 62.8 +/- 19.4, FM 49.4 +/- 21.4 mm, P < 0.001). We conclude that for adult patients, nasal prongs and nasopharyngeal oxygen therapy consume less oxygen and provide greater comfort than facemasks while still maintaining SpO2 > or = 95%.

A National Outbreak of Ralstonia mannitolilytica Associated With Use of a Contaminated Oxygen-Delivery Device Among Pediatric Patients

In August 2005, the Centers for Disease Control and Prevention was notified of a Ralstonia species outbreak among pediatric patients receiving supplemental oxygen therapy with the Vapotherm 2000i (Vapotherm, Inc, Stevensville, MD). The Vapotherm 2000i is a reusable medical device that was used in >900 hospitals in the United States in 2005. Ralstonia are waterborne bacilli that have been implicated in hospital-acquired infections. We initiated an investigation to determine the source of the outbreak and implement infection control and prevention measures. We performed a case-control study at 1 hospital and conducted national case findings to obtain clinical and environmental samples for laboratory analysis. Case-patients had health care-acquired Ralstonia colonization or infection. Isolates were compared by using pulsed-field gel electrophoresis. We tested manufacturer-recommended disinfection protocols for the Vapotherm 2000i under simulated-use conditions. Case-patients at the hospital (n = 5) were more likely to have received Vapotherm therapy than controls. Nationally, Ralstonia mannitolilytica was confirmed in 38 patients (aged 5 days to 7 years); 35 (92%) of the patients were exposed to the Vapotherm 2000i before recovery of the organism. Pulsed-field gel electrophoresis showed related R. mannitolilytica strains from isolates sent from 18 hospitals in 12 states. A Vapotherm machine reprocessed with a protocol proposed by the manufacturer grew Ralstonia spp after 7 days of simulated use. In December 2005, Vapotherm recalled the 2000i. Our findings suggest intrinsic contamination of Vapotherm devices with Ralstonia spp. New medical devices may provide therapy equivalent to current devices yet pose novel reprocessing challenges.

Oxygen: Can we prescribe it correctly?

Introduction Oxygen is one of the most common drugs used in secondary care. It is often used incorrectly on hospital wards, and it has been suggested that prescribing oxygen would facilitate correct administration. However, the knowledge of hospital doctors who would prescribe oxygen, and that of nurses who administer it, has not been tested. Methods A questionnaire was prepared to test a person's knowledge of oxygen delivery devices and their use in different clinical scenarios. This questionnaire was given to 30 junior doctors and 53 nurses working on an acute medical ward in a district general hospital. Results The majority of doctors and nurses could not identify less commonly used oxygen delivery devices, such as a non-rebreathing mask with reservoir bag. A quarter of the doctors and nearly half the nurses were unable to select the correct dose and method of administration of oxygen in the event of cardiorespiratory arrest. The majority prescribed oxygen wrongly in the various clinical scenarios that dealt with respiratory failure. Conclusion Junior doctors and nurses do not have sufficient knowledge and understanding of oxygen therapy to be able to prescribe the drug appropriately and safely.

Oxygen delivery device can also deliver infections

Oxygen delivery device can also deliver infections

Comparison of two demand oxygen delivery devices for administration of oxygen in COPD: Chest 2005;128:2082–7

Comparison of two demand oxygen delivery devices for administration of oxygen in COPD: Chest 2005;128:2082–7

The OxyArm™: A Supplemental Oxygen Delivery Device

Facemasks and nasal cannulae are used to provide supplemental oxygen to patients in the postoperative period after general anesthesia. These devices are associated with several patient complications, including aspiration, hypercarbia, and mechanical trauma. A new device, the OxyArm, is designed to eliminate these problems. It is an "open oxygen" system that does not require physical contact with the patient's face. In this clinical study we evaluated the OxyArm in the immediate postoperative period. Sixty patients received supplemental oxygen via the OxyArm for the first 8 min after tracheal extubation after general anesthesia. Oxygen saturation values were continuously recorded during 3 4-min time periods: 1) while breathing oxygen through an endotracheal tube before tracheal extubation, 2) while breathing oxygen delivered by the OxyArm at 4 L/min 4 min after tracheal extubation, and 3) while breathing oxygen delivered by the OxyArm at 2 L/min 8 min after tracheal extubation. There were no significant differences in oxygen saturation among the three time periods and no patient experienced an oxygen desaturation event less than 88%. Patients and clinicians praised the OxyArm for its comfort and ease of use, allowing nursing facial care without interrupting oxygen therapy. We conclude that the OxyArm delivers adequate levels of oxygen for most patients during the early postoperative period.

Comparison of Nasal Cannulas and the OxyArm in Patients Requiring Chronic Domiciliary Oxygen Therapy

The present study was designed to compare the performance of a new oxygen delivery device, the OxyArm (OA) (Southmedic Inc, Canada), with a standard nasal cannula (NC) (Salter-Style 1600, Salter Labs, USA) for both oxygen delivery and patient preference in patients on long-term oxygen therapy (LTOT). Randomized crossover study conducted in an outpatient setting. Twenty-five clinically stable LTOT patients were randomly assigned to an oxygen device (NC or OA) sequence. The baseline saturation level was determined, and patients were then treated at oxygen flow rates of 2 L/min, 3 L/min, 4 L/min, 5 L/min, 6 L/min and 7 L/min for 10 min each while at rest. Patients were then crossed over to the second device and the procedure was repeated. Oximetry values were then obtained following a 5 min walk test using the same device sequence. Lastly, the patients were sent home for a four-week home OA trial, after which, they filled out a questionnaire. This sample of patients was primarily elderly ex-smokers with severe chronic obstructive pulmonary disease on oxygen therapy for the majority of the day. The primary findings were that the OA and NC were equally effective in delivering oxygen to patients and maintaining their oxygen saturation at both rest (P = 0.82) and during a 5 min walk test (P = 0.83). A patient's personal experience and comfort were identified as the most important factors in deciding on an oxygen device. Most patients felt that the OA was most suited for oxygen therapy while at rest. The OA proved to be similar to the NC in delivering oxygen and maintaining saturation in patients on LTOT. The OA is one of the few alternatives to using NCs for these patients and, with its current design, appears to be most suited for resting conditions.