High-flow Nasal Cannula Devices Research Articles

The Impact of Various High-Flow Nasal Cannula Devices on Transnasal Aerosol Delivery.

Aerosol delivery via high-flow nasal cannula (HFNC) has gained popularity due to the increased use of the modality for treating hypoxemic and hypercapnic respiratory failure. Various HFNC devices are available in the United States; however, the effectiveness of aerosol delivery via HFNC devices remains unclear. Thus, this study aimed to investigate the impact of various commercially available devices on transnasal aerosol delivery. This was a bench study that used a 2-chamber lung model, in which one chamber was connected to an adult manikin with anatomically correct upper-airway proportions. The other chamber was connected to a critical care ventilator used to simulate spontaneous breathing. A size large nasal cannula was placed at the nasal opening of the manikin. Five different HFNC devices (Hamilton-C1, OptiFlow, Airvo2, V60 Plus, and Vapotherm) were compared. Four flow settings were used on each device, with a vibrating mesh nebulizer placed at the humidifier. Salbutamol (2.5 mg/3 mL) was used during the experiments to quantify inhaled drug doses. A collection filter was placed between the manikin's trachea and the lung model. The drug was eluted from the filter and assayed with ultraviolet spectrophotometry (276 nm). Among the 5 HFNC devices, OptiFlow had the highest inhaled dose at 10 L/min (mean ± SD 18.2% ± 1.2%). At 20 L/min, the Hamilton-C1 (mean ± SD 13.5% ± 0.4%) performed marginally better than the OptiFlow (mean ± SD 12.6% ± 1.9%) and Airvo2 (mean ± SD 12.8% ± 1%). At high flow settings (40-60 L/min), the inhaled dose of Hamilton-C1 was 2-3 times that of the Airvo2 and V60 Plus. When compared with the other devices, the mean inhaled dose with the Vapotherm was lower (0.9-2.5%). In all devices, the inhaled dose decreased as the flow increased. Transnasal aerosol delivery was significantly impacted by the types of HFNC devices and flow settings. Nominal doses might need to be adjusted if changing HFNC devices or flow is not an option.

Comparison of actual performance in humidification among different high-flow nasal cannula devices: a bench study

BackgroundThe physiological effects of HFNC devices are closely related to temperature and humidity. HFNC devices from different manufacturers may have varied performances. It is unclear whether there are differences in the humidification performance of different HFNC devices and the degree of differences.MethodsFour integrated HFNC devices (AIRVO 2, Fisher & Paykel Healthcare, Auckland, New Zealand; TNI softFlow 50, TNI Medical AG, Würzburg, Germany; HUMID-BH, RESPIRACARE, Shenyang, China; OH-70C, Micomme, Hunan, China) and a ventilator with an HFNC module (bellavista 1000, Imtmedical, Buchs, Switzerland) were evaluated using their matching circuits. The dew point temperature was set at 31, 34, and 37°C (set-DP). In MR850, it was set to non-invasive mode (34°C/−3°C) and invasive mode (40°C/−3°C), respectively. At each level of set-DP, the flow was set from 20 L/min up to its maximum set limit at a gradient of 5 L/min or 10 L/min. After stabilization, the dew point temperature, temperature, relative humidity, and flow rate of the delivered gas from the cannulas were recorded.ResultsThere were significant differences in actual-DP among these devices at any set-DP (p < 0.001). The actual-DP of OH-70C and TNI softFlow 50 was lower than set-DP, and the difference between the actual-DP and the set-DP of these two devices increased with the increase of set-DP. AIRVO 2, bellavista 1000 (MR850), and HUMID-BH can provide the nominal humidity at 37°C. The actual-DP increased with the increase of set-flow under each set-DP in AIRVO 2, TNI softFlow 50 and bellavista 1000 (MR850), but decreased when the set-flow was greater than 60 L/min. The actual-T of the delivered gas was higher than actual-DP in all devices and was higher than set-DP in AIRVO 2 and HUMID-BH.ConclusionSet-flow, set-DP, and types of devices will affect the actual temperature and humidity of the delivered gas. AIRVO 2, bellavista 1000 (MR850), and HUMID-BH can provide the nominal humidity at 37°C and may be more suitable for tracheotomy patients. The flow rate over 60 L/min should be set with caution.

Monitoring the Occurrence of Alarms in High Flow Nasal Cannula (HNFC) Using IoT-Based Thinger.io Platform for COVID-19 Isolation Room

Covid-19 has become a virus that has become a world pandemic and this virus has caused mass deaths because medical personnel have difficulty treating patients when oxygen levels in the blood have fallen to critical levels. HFNC (High Flow Nasal Cannula) is a method of administering additional oxygen to patients with acute respiratory failure. The use of HFNC in recent years has been highly recommended as a solution to provide supplemental oxygen to patients. Administration of HFNC to COVID-19 patients begins at a flow range of 30-60 LPM.Unfortunately, HFNC, which used to exist, can only be monitored manually, resulting in the transmission of HFNC-produced aerosols between patients and staff. So this study aims to analyze errors in HFNC that cause a decrease in flow to HFNC using a flow sensor as a sensor to detect leaks or other flow errors from the HFNC output hose and monitor if there is a blockage through IoT in the form of notifications.This research method uses the Pre-experimental with the After Only Design type. In this design, the researcher only used one group of subjects and only looked at the results without measuring and knowing the initial conditions, but there was already a comparison group. The independent variable in this study was the HFNC error condition. While the dependent variable in this study is the data flow read by the sensor, where IoT notifications and device status show error leaks. The sensors used in this research are MPX5700GP pressure sensors and SEN0343 Differential Pressure sensors as flow sensors. The benefit of this research is that in addition to reducing the burden on medical staff in handling Covid-19 patients, it can also minimize transmission between staff and patients caused by high aerosol production by this HFNC device, this is because HFNC device alarm monitoring can be monitored in the nurse's room via internet technology. In conclusion, to obtain maximum benefits from this research, it is necessary to select a sensor that truly has a high enough resistance to humidity produced by this HFNC humidifier's water vapor.

High-flow nasal cannula: Evaluation of the perceptions of various performance aspects among Chinese clinical staff and establishment of a multidimensional clinical evaluation system.

ObjectiveIn order to facilitate education for clinical users, performance aspects of the high-flow nasal cannula (HFNC) devices were evaluated in the present study. A multidimensional HFNC clinical evaluation system was established accordingly.Materials and MethodsClinical staff from Chinese hospitals were invited to participate in an online questionnaire survey. The questionnaire was mainly about the accuracy of temperature, flow rate, and oxygen concentration of HFNC, as well as its humidification capacity. We also investigated how the clinical staff of different professions made decisions on HFNC evaluation indicators. Based on the results of the questionnaire survey of clinicians with rich experience in using HFNC, the relative weights of temperature accuracy, flow velocity accuracy, oxygen concentration accuracy, and humidification ability of HFNC equipment were calculated by the AHP to establish a clinical evaluation system. Four kinds of common HFNC devices were tested and evaluated, and the clinical performance of the four kinds of HFNC devices was evaluated by the new scoring system.ResultsA total of 356 clinicians participated in and completed the questionnaire survey. To ensure the reliability of the HFNC evaluation system, we only adopted the questionnaire results of clinicians with rich experience in using HFNCs. Data from 247 questionnaires (80 doctors, 105 nurses, and 62 respiratory therapists [RTs]) were analyzed. A total of 174 participants used HFNC more than once a week; 88.71% of RTs used HFNC ≥ 1 score daily, 62.86% of nurses used HFNC ≥ 1 score daily, and 66.25% of doctors used HFNC ≥ 1 daily. There was no significant difference in the frequency of use between doctors and nurses. Finally, the relative weights of temperature accuracy (0.088), humidification capacity (0.206), flow velocity accuracy (0.311), and oxygen concentration accuracy (0.395) in the HFNC clinical evaluation system were obtained. The relative weights of clinicians with different occupations and the frequency of HFNC use were obtained. After testing four kinds of HFNC devices through the evaluation system, it was found that the four kinds of HFNC devices have different advantages in different clinical performances, and AiRVO2 has excellent performance with regard to temperature accuracy and humidification ability. HF-75A and NeoHiF-i7 are good at ensuring the stability of oxygen concentration and the accuracy of the flow velocity of the transported gas, while OH-80S is relatively stable in all aspects.ConclusionThe clinical evaluation system of HFNC is based on the weight of the experience of clinical personnel with different medical backgrounds. Although the existing practitioners have different educational backgrounds (academic qualifications, majors), our evaluation system can enhance clinical staff’s awareness of HFNC and further optimize the clinical use of HFNC.

A Bench Comparison of the Effect of High-Flow Oxygen Devices on Work of Breathing.

Oxygen therapy via high-flow nasal cannula (HFNC) has been extensively used during the COVID-19 pandemic. The number of devices has also increased. We conducted this study to answer the following questions: Do HFNC devices differ from the original device for work of breathing (WOB) and generated PEEP? Seven devices were tested on ASL 5000 lung model. Compliance was set to 40 mL/cm H2O and resistance to 10 cm H2O/L/s. The devices were connected to a manikin head via a nasal cannula with FIO2 set at 0.21. The measurements were performed at baseline (manikin head free of nasal cannula) and then with the cannula and the device attached with oxygen flow set at 20, 40, and 60 L/min. WOB and PEEP were assessed at 3 simulated inspiratory efforts (-5, -10, -15 cm H2O muscular pressure) and at 2 breathing frequencies (20 and 30 breaths/min). Data were expressed as median (first-third quartiles) and compared with nonparametric tests to the Optiflow device taken as reference. Baseline WOB and PEEP were comparable between devices. Over all the conditions tested, WOB was 4.2 (1.0-9.4) J/min with the reference device, and the relative variations from it were 0, -3 (2-4), 1 (0-1), -2 (1-2), -1 (1-2), and -1 (1-2)% with Airvo 2, G5, HM80, T60, V500, and V60 Plus devices, respectively, (P < .05 Kruskal-Wallis test). PEEP was 0.9 (0.3-1.5) cm H2O with Optiflow, and the relative differences were -28 (22-33), -41 (38-46), -30 (26-36), -31 (28-34), -37 (32-42), and -24 (21-34)% with Airvo 2, G5, HM80, T60, V500, and V60 Plus devices, respectively, (P < .05 Kruskal-Wallis test). WOB was marginally higher and PEEP marginally lower with devices as compared to the reference device.

High-Flow Nasal Cannula Oxygen Therapy: Physiological Mechanisms and Clinical Applications in Children.

High-flow nasal cannula (HFNC) oxygen therapy has rapidly become a popular modality of respiratory support in pediatric care. This is undoubtedly due to its ease of use and safety, which allows it to be used in a wide variety of settings, ranging from pediatric intensive care to patients' homes. HFNC devices make it possible to regulate gas flow and temperature, as well as allowing some nebulized drugs to be administered, features very useful in children, in which the balance between therapeutic effectiveness and adherence to treatment is pivotal. Although the physiological effects of HFNC are still under investigation, their mechanisms of action include delivery of fixed concentration of oxygen, generation of positive end-expiratory pressure, reduction of the work of breathing and clearance of the nasopharyngeal dead space, while providing optimal gas conditioning. Nevertheless, current evidence supports the use of HFNC mainly in moderate-to-severe bronchiolitis, whereas for asthma exacerbations and breath sleeping disorders there is a lack of randomized controlled trials comparing HFNC to continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV), which are essentials for the identification of response and non-response predictors. In this regard, the development of clinical guidelines for HFNC, including flow settings, indications, and contraindications is urgently needed.

Mitigating Fugitive Aerosols During Aerosol Delivery via High-Flow Nasal Cannula Devices.

Aerosol delivery via high-flow nasal cannula (HFNC) has attracted clinical interest in recent years. However, both HFNC and nebulization are categorized as aerosol-generating procedures (AGPs). In vitro studies raised concerns that AGPs had high transmission risk. Very few in vivo studies examined fugitive aerosols with nebulization via HFNC, and effective methods to mitigate aerosol dispersion are unknown. Two HFNC devices (Airvo 2 and Vapotherm) with or without a vibrating mesh nebulizer were compared; HFNC alone, surgical mask over HFNC interface, and HFNC with face tent scavenger were used in a random order for 9 healthy volunteers. Fugitive aerosol concentrations at sizes of 0.3-10.0 μm were continuously measured by particle sizers placed at 1 and 3 ft from participants. On a different day, 6 of the 9 participants received 6 additional nebulizer treatments via vibrating mesh nebulizer or small-volume nebulizer (SVN) with a face mask or a mouthpiece with/without an expiratory filter. In vitro simulation was employed to quantify inhaled dose of albuterol with vibrating mesh nebulizer via Airvo 2 and Vapotherm. Compared to baseline, neither HFNC device generated higher aerosol concentrations. Compared to HFNC alone, vibrating mesh nebulizer via Airvo 2 generated higher 0.3-1.0 μm particles (all P < .05), but vibrating mesh nebulizer via Vapotherm did not. Concentrations of 1.0-3.0 μm particles with vibrating mesh nebulizer via Airvo 2 were similar with vibrating mesh nebulizer and a mouthpiece/face mask but less than SVN with a mouthpiece/face mask (all P < .05). Placing a surgical mask over HFNC during nebulization reduced 0.5-1.0 μm particles (all P < .05) to levels similar to the use of a nebulizer with mouthpiece and expiratory filter. In vitro the inhaled dose of albuterol with vibrating mesh nebulizer via Airvo 2 was ≥ 6 times higher than vibrating mesh nebulizer via Vapotherm. During aerosol delivery via HFNC, Airvo 2 generated higher inhaled dose and consequently higher fugitive aerosols than Vapotherm. Simple measures, such as placing a surgical mask over nasal cannula during nebulization via HFNC, could effectively reduce fugitive aerosol concentrations.

The Impact of High-Flow Nasal Cannula Device, Nebulizer Type, and Placement on Trans-Nasal Aerosol Drug Delivery.

Aerosol delivery via high-flow nasal cannula (HFNC) has been increasingly used in recent years. However, the effects of different HFNC devices, nebulizer types, and placement on aerosol deposition remain largely unknown. An adult manikin with anatomically correct upper airway was used with a collection filter placed between the manikin's trachea and a breathing simulator, composed of a dual-chamber model lung driven by a critical care ventilator. Three HFNC device configurations were compared, with vibrating mesh nebulizer and small-volume nebulizer placed at the humidifier (inlet for Optiflow and outlet for Airvo 2) and proximal to the nasal cannula at gas flows of 10, 20, 40 and 60 L/min, in quiet and distressed breathing patterns. Albuterol (2.5 mg) was nebulized for each condition (no. = 3). The drug was eluted from the collection filter and assayed with ultraviolet spectrophotometry (276 nm). At all settings, except when a nebulizer was placed proximal to the nasal cannula with the Optiflow and when the HFNC flow was set at 60 L/min, the vibrating mesh nebulizer generated a higher inhaled dose than did the small-volume nebulizer (all P < .05). With the exception of distressed breathing at an HFNC flow of 10 L/min, the inhaled dose with the vibrating mesh nebulizer placed at the humidifier was greater than with the vibrating mesh nebulizer placed proximal to the nasal cannula (all P < .05), Optiflow provided a higher inhaled dose than did Airvo 2 with either AirSpiral or 900PT501 circuits with the vibrating mesh nebulizer placed at the humidifier (all P < .05). During transnasal aerosol delivery, the vibrating mesh nebulizer generated a higher inhaled dose than did the small-volume nebulizer when the nebulizer was placed at the humidifier. With the vibrating mesh nebulizer placed at the humidifier and an HFNC flow > 10 L/min, the inhaled dose was higher than with the vibrating mesh nebulizer placed proximal to the nasal cannula, and the inhaled dose was higher with Optiflow than with Airvo 2.

Hygrometric Performances of Different High-Flow Nasal Cannula Devices: Bench Evaluation and Clinical Tolerance.

High-flow nasal cannula (HFNC) is increasingly used for the management of respiratory failure. Settings include [Formula: see text], total gas flow, and temperature target. Resulting absolute humidity (AH) at the nasal cannula may affect clinical tolerance, and optimal settings with respect to hygrometry remain poorly documented. A bench study was designed to assess AH delivered by 4 HFNC devices (Optiflow, Airvo 2, Precision Flow, and Hydrate) according to flow, ambient temperature, and other available settings. Clinical tolerance of different levels of hygrometry (20, 30, and 40 mg H2O/L) was evaluated in 15 healthy volunteers. With [Formula: see text] set at 1.0, normal ambient temperature, and settings made accordingly to the manufacturers' recommendations, mean ± SD AH was 42.2 ± 3.1, 39.5 ± 1.8, 35.7 ± 2.0, and 32.9 ± 2.7 mg H2O/L for the Airvo 2, Optiflow, Hydrate, and Precision Flow, respectively, (P < .001). AH dropped from -3.5 to -10.7 mg H2O/L (P <. 001) with high ambient temperature, except for the Precision Flow. Increasing flow did not significantly affect AH except for the Precision Flow (from 36.4 ± 1.6 to 29.8 ± 0.2 mg H2O/L at 10 and 40 L/min, respectively, [P < .001]). The lowest AH was encountered with the Optiflow set with noninvasive ventilation (NIV) mode, without compensation algorithm, and at high ambient temperature (14.2 ± 1.5 mg H2O/L). In studied subjects, AH significantly affected breathing comfort, reduced from 7.0 ± 1.0 to 3.0 ± 2.0 at 40 and 20 mg H2O/L, respectively, (P < .001). Comfort was similar at 30 and 40 mg H2O/L. When used according to manufacturer's recommendations and at normal ambient temperature, all the HFNC devices evaluated achieved satisfactory hygrometric output with respect to breathing comfort evaluated in healthy subjects (≥ 30 mg H2O/L). Substantial differences exist between devices, and optimal knowledge of their working principles is required as inappropriate usage may dramatically alter efficacy and clinical tolerance.

Pharyngeal pressure due to high-flow nasal cannula devices in preterm infants.

In infants, a high-flow nasal cannula (HFNC) generates continuous positive pressure on the upper airway. This study aimed to evaluate the association between pharyngeal pressure and flow rate, and the association between pharyngeal pressure and bodyweight for two types of HFNC devices commonly used in preterm infants: the Optiflow Junior, hereafter "FP" (Fisher & Paykel, Auckland, New Zealand), and the Precision Flow, hereafter "VT" (Vapotherm, Exeter, NH, USA). Pharyngeal pressure measurements were performed in 12 preterm infants who received HFNC support. Flow rates of 1 to 4L/kg/min were studied. The median weight at the time of measurement was 1,290g (range, 953-1,932g). The FP was used in eight infants and the VT in four. In both of the groups, the flow rate and pharyngeal pressure appeared to be positively correlated except for the premature cannula in the FP group. At a flow rate of ≥2L/kg/min, there was a positive correlation between the bodyweight and pharyngeal pressure in infants with premature and neonatal cannulas in the FP group. Conversely, at the same flow rate, there was a negative correlation between the bodyweight and pharyngeal pressure in infants with a SOLO cannula in the VT group. In preterm infants, the flow rate and pharyngeal pressure were positively correlated in many HFNC cannulas. However, the pharyngeal pressure and bodyweight appeared to be positively and negatively correlated in the FP and VT groups, respectively. Future studies with larger sample sizes should further investigate this issue.

High flow nasal cannula for adult acute hypoxemic respiratory failure in the ED setting.

IntroductionHigh flow nasal cannula (HFNC) is a noninvasive ventilation (NIV) system that has demonstrated promise in the emergency department (ED) setting.ObjectiveThis narrative review evaluates the utility of HFNC in adult patients with acute hypoxemic respiratory failure in the ED setting.DiscussionHFNC provides warm (37 °C), humidified (100% relative humidity) oxygen at high flows with a reliable fraction of inspired oxygen (FiO2). HFNC can improve oxygenation, reduce airway resistance, provide humidified flow that can flush anatomical dead space, and provide a low amount of positive end expiratory pressure. Recent literature has demonstrated efficacy in acute hypoxemic respiratory failure, including pneumonia, acute respiratory distress syndrome (ARDS), coronavirus disease 2019 (COVID-19), interstitial lung disease, immunocompromised states, the peri-intubation state, and palliative care, with reduced need for intubation, length of stay, and mortality in some of these conditions. Individual patient factors play an important role in infection control risks with respect to the use of HFNC in patients with COVID-19. Appropriate personal protective equipment, adherence to hand hygiene, surgical mask placement over the HFNC device, and environmental controls promoting adequate room ventilation are the foundation for protecting healthcare personnel. Frequent reassessment of the patient placed on HFNC is necessary; those with severe end organ dysfunction, thoracoabdominal asynchrony, significantly increased respiratory rate, poor oxygenation despite HFNC, and tachycardia are at increased risk of HFNC failure and need for further intervention.ConclusionsHFNC demonstrates promise in several conditions requiring respiratory support. Further randomized trials are needed in the ED setting.

Comparative study of high flow nasal catheter device and noninvasive positive pressure ventilation for sequential treatment in sepsis patients after weaning from mechanical ventilation in intensive care unit.

The hypoxemia condition after mechanical ventilation (MV) weaning is not rare among sepsis patients, so we compared the efficacy in two different intervention groups: high-flow nasal cannula device group and non-invasive positive pressure ventilation (NPPV) group. This is a retrospective cohort study. Participants were patients with sepsis receiving high-flow nasal catheter (HFNC) device or NPPV within 24 hours after weaning from MV. The primary outcome was tracheal re-intubation within 72 hours after extubation. Secondary outcomes included: oxygenation index, complication rate, patient comfort evaluation, HFNC/NPPV treatment time, ICU length of stay (LOS), ICU mortality, and in-hospital 28-day mortality. A total of 283 patients were included in the study with 167 in the HFNC group and 116 in the NPPV group. The re-intubation rates after extubation in both groups were respectively 4.2% and 5.2% without significant difference. Patients in the HFNC group experienced lower incidence of delirium, reflux aspiration, facial pressure ulcer and other complications, and higher score of patients comfort than that in the NPPV group. There was no significant difference in ICU LOS, ICU mortality and in-hospital 28-day mortality between the two groups. HFNC and NPPV have similar efficacy in the sequential treatment of sepsis patients after weaning from MV. Compared with NPPV, those extubated to HFNC had lower rate of complications such as reflux aspiration and facial pressure ulcers. The patients extubation to HFNC is more comfortable (and associated with less delirium) than to NPPV.

Comparison of Actual Performance in the Flow and Fraction of Inspired O2 among Different High-Flow Nasal Cannula Devices: A Bench Study.

Background High-flow nasal cannula (HFNC) oxygen therapy has been recommended for use in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure and many other clinical conditions. HFNC devices produced by different manufacturers may have varied performance. Whether there is a difference in these devices and the extent of the differences in performance remain unknown. Methods Four HFNC devices (AIRVO 2, TNI softFlow 50, HUMID-BH, and OH-70C) and a ventilator with an HFNC module (bellavista 1000) were evaluated. The flow was set at 20, 25, 30, 35, 40, 45, 50, 60, 70, and 80 L/min, and the FiO2 was set at 21%, 26%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, and 90%. Then, one side of the cannulas was clipped to simulate the compression, bending, or blocking of the nasal cannulas. The flow and FiO2 of the delivered gas were recorded and compared among settings and devices. Results The actual-flow and actual-FiO2 delivered by different settings and devices varied. AIRVO 2 had superior performance in flow and FiO2 accuracy. bellavista 1000 and OH-70C had good performance in the accuracy of actual-flows and actual-FiO2, respectively. bellavista 1000 and HUMID-BH had a larger flow range from 10 to 80 L/min, but only bellavista 1000 could provide a stable flow with an excessive resistance up to 60 L/min. TNI softFlow 50 had the best flow compensation and could provide sufficient flow with excessive resistance at 20–50 L/min. Conclusions The variation in flow, FiO2 settings, and devices could influence the actual-flow and actual-FiO2 delivered. AIRVO 2 and OH-70C showed better FiO2 accuracy. TNI softFlow 50, bellavista 1000, and HUMID-BH could lower the risk of insufficient flow support due to accidental compression or blocking of the cannulas. In addition, ventilators with HFNC modules provided comparable flow and FiO2 and could be an alternative to standalone HFNC devices.

Low flow nasal oxygen supplementation in addition to non-rebreathing mask: An alternative to high flow nasal cannula oxygenation for acute hypoxemic COVID-19 patients in resource limited settings

Approximately 14% COVID-19 patients, develop acute hypoxic respiratory failure. A high flow nasal cannula device might be preferred to obtain an oxygen saturation above 90% in these cases. In resource limited settings, where high flow nasal cannula is not an option, additional low flow oxygen therapy through nasal prongs could be added to non-rebreathing mask with a reservoir bag. The possible mechanisms of the improved oxygenation could be: 1. improved oxygen-air mixing in large airways, 2. increased oxygen concentration inside the non-rebreathing mask, 3. decrease in rebreathing of carbon-dioxide from the non-rebreathing mask. This method of oxygen supplementation is easy to assemble, cost-effective and helpful in management of acute hypoxemic COVID-19 patients, whenever there is crisis of high flow nasal cannula machine. Its effectiveness needs to be assessed by a randomized controlled trial.

High-Flow Nasal Cannula Therapy for Exertional Dyspnea in Patients with Cancer: A Pilot Randomized Clinical Trial.

Exertional dyspnea is common in patients with cancer and limits their function. The impact of high-flow nasal cannula on exertional dyspnea in nonhypoxemic patients is unclear. In this double-blind, parallel-group, randomized trial, we assessed the effect of flow rate (high vs. low) and gas (oxygen vs. air) on exertional dyspnea in nonhypoxemic patients with cancer. Patients with cancer with oxygen saturation >90% at rest and exertion completed incremental and constant work (80% maximal) cycle ergometry while breathing low-flow air at 2 L/minute. They were then randomized to receive high-flow oxygen, high-flow air, low-flow oxygen, or low-flow air while performing symptom-limited endurance cycle ergometry at 80% maximal. The primary outcome was modified 0-10 Borg dyspnea intensity scale at isotime. Secondary outcomes included dyspnea unpleasantness, exercise time, and adverse events. Seventy-four patients were enrolled, and 44 completed the study (mean age 63; 41% female). Compared with low-flow air at baseline, dyspnea intensity was significantly lower at isotime with high-flow oxygen (mean change, -1.1; 95% confidence interval [CI], -2.1, -0.12) and low-flow oxygen (-1.83; 95% CI, -2.7, -0.9), but not high-flow air (-0.2; 95% CI, -0.97, 0.6) or low-flow air (-0.5; 95% CI, -1.3, 0.4). Compared with low-flow air, high-flow oxygen also resulted in significantly longer exercise time (difference + 2.5 minutes, p = .009), but not low-flow oxygen (+0.39 minutes, p = .65) or high-flow air (+0.63 minutes, p = .48). The interventions were well tolerated without significant adverse effects. Our preliminary findings support that high-flow oxygen improved both exertional dyspnea and exercise duration in nonhypoxemic patients with cancer. (ClinicalTrials.gov ID: NCT02357134). In this four-arm, double-blind, randomized clinical trial examining the role of high-flow nasal cannula on exertional dyspnea in patients with cancer without hypoxemia, high-flow oxygen, but not high-flow air, resulted in significantly lower dyspnea scores and longer exercise time. High-flow oxygen delivered by high-flow nasal cannula devices may improve clinically relevant outcomes even in patients without hypoxemia.

Surgical mask on top of high-flow nasal cannula improves oxygenation in critically ill COVID-19 patients with hypoxemic respiratory failure

ObjectiveCritically ill patients admitted in ICU because of COVID-19 infection display severe hypoxemic respiratory failure. The Surviving Sepsis Campaign recommends oxygenation through high-flow nasal cannula over non-invasive ventilation. The primary outcome of our study was to evaluate the effect of the addition of a surgical mask on a high-flow nasal cannula system on oxygenation parameters in hypoxemic COVID-19 patients admitted in ICU who do not require urgent intubation. The secondary outcomes were relevant changes in PaCO2 associated with clinical modifications and patient’s feelings.DesignWe prospectively assessed 21 patients admitted in our mixed Intensive Care Unit of the Cliniques Universitaires Saint Luc.Main resultsWhile FiO2 was unchanged, we demonstrate a significant increase of PaO2 (from 59 (± 6), to 79 mmHg (± 16), p < 0.001), PaO2/FiO2 from 83 (± 22), to 111 (± 38), p < 0.001) and SaO2 (from 91% (± 1.5), to 94% (± 1.6), p < 0.001), while the patients were under the surgical mask. The SpO2 returned to pre-treatment values when the surgical mask was removed confirming the effect of the device rather than a spontaneous positive evolution.ConclusionA surgical mask placed on patient’s face already treated by a High-flow nasal cannula device improves COVID-19 patient’s oxygenation admitted in Intensive Care Unit for severe hypoxemic respiratory failure without any clinically relevant side.

High-flow nasal oxygen reduces endotracheal intubation: a randomized clinical trial.

Background:The benefits of high-flow nasal cannula (HFNC) as primary intervention in patients with acute hypoxemic respiratory failure (AHRF) are still a matter in debate. Our objective was to compare HFNC therapy versus conventional oxygen therapy (COT) in the prevention of endotracheal intubation in this group of patients.Methods:An open-label, controlled and single-centre clinical trial was conducted in patients with severe AHRF, defined by a PaO2/FIO2 ratio ⩽200, to compare HFNC with a control group (CG) treated by COT delivered through a face mask, with the need to perform intubation as the primary outcome. The secondary outcomes included tolerance of the HFNC device and to look for the predictive factors for intubation in these patients.Results:A total of 46 patients were included (22 in the COT group and 24 in the HFNC group) 48% of whom needed intubation: 63% in the COT group and 33% in the HFNC group, with significant differences both in intention to treat [χ2 = 4.2; p = 0.04, relative risk (RR) = 0.5; confidence interval (CI) 95%: 0.3–1.0] and also in treatment analysis (χ2 = 4.7; p = 0.03; RR = 0.5; IC 95%: 0.3–0.9) We obtained a number needed to treat (NNT) = 3 patients treated to avoid an intubation. Intubation occurred significantly later in the HFNC group. Estimated PaO2/FIO2, respiratory rate and dyspnea were significantly better in the HFNC group. Patients treated with HFNC who required intubation presented significant worsening after the first 8 h, as compared with non-intubated HFNC group patients. Mortality was 22% with no differences. The HFNC group patients were hospitalized for almost half of the time in the intensive care unit (ICU) and in the ward, with significantly less hospital length of stay. A total of 14 patients in the HFNC group (58%) complained of excessive heat and 17% of noise; 3 patients did not tolerate HFNC.Conclusion:Patients with severe acute hypoxemic respiratory failure who tolerate HFNC present a significantly lower need for endotracheal intubation compared with conventional oxygen therapy.Clinical Trial RegisterEUDRA CT number: 2012-001671-36 The reviews of this paper are available via the supplemental material section.

In vitro comparison of unit dose vs infusion pump administration of albuterol via high-flow nasal cannula in toddlers.

Transnasal pulmonary aerosol delivery using high-flow nasal cannula (HFNC) devices has become a popular route of aerosol administration in toddlers. Clinically, albuterol is administered using an infusion pump or unit doses. However, little evidence is available to compare the two administration strategies. A toddler manikin (15 kg) with appropriate anatomic airway was connected with collecting filter to a simulator of distressed breathing. HFNC device with mesh nebulizer placed at the inlet of a humidifier at 37°C, with the gas flow set at 25 and 3.75 L/min. Five milligrams of albuterol was delivered in all experiments. With infusion pump administration, albuterol concentrations of 5 and 1 mg/mL were delivered at 4 and 20 mL/hr for 15 minutes. With unit dose administration, 1 mL (5 mg/mL) and 2 mL (2.5 mg/mL) of albuterol were nebulized. Additional tests with mouth open and nebulizers via mask were using 5 mg/1 mL for mesh nebulizer and 5 mg/3 mL for jet nebulizer (n = 3). The drug was eluted from the filter and assayed with UV spectrophotometry (276 nm). The inhaled dose was higher with unit dose than infusion pump administration with gas flows of 25 L/min (2.66 ± 0.38 vs 1.16 ± 0.28%; P = .004) and 3.75 L/min (10.51 ± 1.29 vs 8.58 ± 0.68%; P = .025). During unit dose administration, compared with closed-mouth breathing, open-mouth breathing generated a higher inhaled dose at 3.75 L/min and lower inhaled dose at 25 L/min. Compared to the nebulizers via mask with both open and closed-mouth breathing, nebulization via HFNC at 3.75 L/min generated greater inhaled dose, while HFNC at 25 L/min generated lower inhaled dose. During transnasal aerosol delivery, the inhaled dose was higher with medication administrated using unit dose than using an infusion pump.

High-flow versus standard nasal cannula in morbidly obese patients during colonoscopy: A prospective, randomized clinical trial

Study objectiveMorbid obesity is associated with adverse airway events including desaturation during deep sedation. Prior works have suggested that proprietary high-flow nasal cannula devices generate positive pressure to all airway structures and may be superior to standard (low-flow) nasal cannula for prevention of desaturation. We hypothesized that, at a similar fraction of inspired oxygen (FiO2), use of a High-Flow Nasal Cannula (HFNC) at maximum flow rate would result in a lower incidence of intra-procedural desaturation episodes in morbidly obese patients compared to standard nasal cannula (SNC) during deep sedation with propofol. DesignThis is a pragmatic, prospective, randomized clinical trial at one hospital (NCT03148262, UTSW#112016-058). Morbidly obese patients were randomized to HFNC during propofol sedation for colonoscopy. HFNC was performed using maximum flow rates of 60 liters per minute (LPM) and FiO2 of 0.36–0.40, whereas SNC was performed at 4LPM. The primary endpoint was incidence of arterial oxygen desaturation <90% measured by pulse oximetry. At midpoint enrollment the Data Monitoring Committee (DMC) performed a pre-planned O'Brien and Fleming futility test. Main resultsPatients were randomized to HFNC (n = 28) or SNC (n = 31). Interim analysis of the primary endpoint showed that the desaturation rates in the HFNC group (39.3%) and the SNC group (45.2%) were not significantly different (p = 0.79). The DMC halted the trial at that point due to futility. ConclusionAt similar FiO2, HFNC was not significantly different from SNC for prevention of arterial oxygen desaturation in morbidly obese patients undergoing propofol sedation for colonoscopy.

High-Flow Nasal Cannula Practice Patterns Reported by Neonatologists and Neonatal Nurse Practitioners in the United States.

High-flow nasal cannula (HFNC) is widely used to treat neonatal respiratory conditions. Significant evidence emerged in recent years to guide practice, yet current practice patterns and their alignment with the evidence remain unknown. To examine current HFNC practice patterns and availability of clinical practice guidelines used in neonatal intensive care units in the United States. A nonexperimental, descriptive study was designed using a web-based survey to elicit a convenience sample of US neonatal providers. Quantitative data were analyzed using descriptive statistics, χ tests were used to test for differences among the categories, and post hoc comparisons among each combination of categories were conducted using a Bonferroni-corrected α of .05 to determine significance as appropriate. A total of 947 responses were analyzed (626 neonatologists and 321 neonatal nurse practitioners). Univariate analyses suggested wide variations in practice patterns. One-third of the respondents used clinical guidelines, the majority utilized HFNC devices in conjunction with nasal continuous positive airway pressure, more than two-thirds used HFNC as a primary respiratory support treatment, and among all respondents, significant differences related to HFNC device types were reported. US providers revealed wide practice variations related to HFNC therapy. In addition, type of device used appears to impact practice patterns and approaches. Use of standardized guidelines was reported by one third of the respondents, and as such may be the contributing factor for wide practice variations. Future Research is needed to target aspects of practice where practice variations exist, or practice is not supported by evidence. Significant practice differences related to the device types should be considered in future research design.