High-flow Nasal Oxygen Therapy Research Articles

Performance Characterisation of the Airvo2TM Nebuliser Adapter in Combination with the Aerogen SoloTM Vibrating Mesh Nebuliser for in Line Aerosol Therapy during High Flow Nasal Oxygen Therapy.

High flow oxygen (HFO) therapy is a well-established treatment in respiratory disease. Concurrent aerosol delivery can greatly expediate their recovery. The aim of this work was to complete a comprehensive characterisation of one such HFO therapy system, the Airvo2TM, used in combination with the Aerogen SoloTM vibrating mesh nebuliser. Representative adult, infant, and paediatric head models were connected to a breathing simulator via a collection filter placed at the level of the trachea. A tracheostomy interface and nasal cannulas were used to deliver the aerosol. Cannula size and gas flow rate were varied across the full operating range recommended by the manufacturer. The tracheal and emitted doses were quantified via UV-spectrophotometry. The aerosol droplet diameter at the exit of the nares and tracheal interface was measured via cascade impaction. High gas flow rates resulted in low emitted and tracheal doses (%). Nasal cannula size had no significant effect on the tracheal dose (%) available in infant and paediatric models. Higher gas flow rates resulted in smaller aerosol droplets at the exit of the nares and tracheostomy interface. Gas flow rate was found to be the primary parameter affecting aerosol delivery. Thus, gas flow rates should be kept low and where possible, delivered using larger nasal cannulas to maximise aerosol delivery.

New Treatment modality for Burn Injury Related ARDS : High-Flow Nasal Oxygen Therapy in Major Burns.

Pulmonary insufficiency is the primary cause of death in cases of major burns accompanied by inhalation damage. It is important to consider the impact on the face and neck in flame burns. Early implementation of bronchial hygiene measures and oxygenation treatment in inhalation injury can reduce mortality. This case series presents the effects of high-flow nasal oxygen application on patient outcomes in major burns and inhalation injury. This report discusses three different patients. One patient, a 29-year-old male with 35% TBSA burns, received high-flow nasal oxygen (HFNO) treatment for inhalation injury on the sixth day after the trauma. After 72 hours of HFNO application, the patient's pulmonary symptoms improved. The second patient had 60% TBSA burns and developed respiratory distress symptoms on the fifth day after the trauma. After 7 days of HFNO application, all symptoms and findings of acute respiratory distress syndrome (ARDS) were resolved. HFNO has used for the treatment of ARDS releated to major burn ( 60% of burned TBSA) 28 years-old patient and improvement was achived. The use of HFNO in pulmonary insufficiency among burn patients has not been reported previously. This series of patient cases demonstrates the successful application of HFNO in treating inhalation injury and burn-related ARDS. However, further clinical studies are necessary to increase its clinical utilization.

High velocity nasal insufflation versus non-invasive ventilation in acute respiratory failure: a comparative study

Background In order to treat respiratory failure, thermo-humidified nasal high flow oxygen (NHFO) therapy is being used more and more. In several clinical scenarios, NHFO has recently gained popularity as alternative noninvasive respiratory ventilation. Aim The aim is to assess the role of high velocity nasal insufflation (HVNI) versus noninvasive ventilation (NIV) in acute respiratory failure. Patients and methods This is a prospective randomized clinical study conducted on 60 patients admitted to the Chest Department at Menoufia University Hospital with acute respiratory failure. Patients were randomized to receive either noninvasive positive pressure ventilation using an oronasal mask or high-velocity nasal insufflation (initial flow was at 30-40 l/min; temperature was adjusted to 37°C; fraction of inspired oxygen 1.0) with clinical monitoring and arterial blood gas (ABG) monitoring after 2, 6, 12, and 24 h. Results The therapeutic impact of both, HVNI and NIV, on pressure of arterial carbon dioxide (PaCO2), hydrogen ion concentration, arterial oxygen saturation and pressure of arterial oxygen (PaO2) over time was almost similar. There was an improvement in dyspnea and a decrease in respiratory rate over time when compared with baseline results in both groups. There was no statistical difference between both groups. The failure rate in type I respiratory failure (RF) was 33.3% in the HVNI group and 28.6% in the NIV group (P-value 0.7). The failure rate in type II RF was 41.7% in the HVNI group and 25% in the NIV group (P-value 0.3). HVNI was more comfortable for patients and provided better communication and oral intake. Conclusion This study demonstrates that the HVNI was comparable to the NIV in the management of hypoxemic respiratory failure and could be used as a noninvasive method of ventilation alternative to the BiPAP in hypercapnic RF, with more comfortability and better communication in the HVNI group.

Gastric Insufflation with High Flow Nasal Oxygen Therapy in Adult Patients Admitted to Intensive Care Unit: An Observational Study.

With the provision of a small positive end-expiratory pressure (PEEP) effect, high-flow nasal oxygen (HFNO) therapy carries a risk of stomach distension. The present study was conducted to find out the air leak in the gastric antrum leading to gastric distension in adult patients with acute respiratory failure receiving HFNO therapy. Adult patients with early hypoxemic respiratory failure requiring HFNO therapy were enrolled in this trial. Before initiation of HFNO therapy, baseline gastric volume (GV) and the average number of peristaltic contractions over one minute were measured using ultrasound. Once the patient was stabilized on HFNO therapy, a 2nd, 3rd, and 4th ultrasound scans were acquired at 10, 20, and 30 minutes respectively. Vitals and blood gas values were recorded at the baseline and after 30 min of initiation of HFNO therapy. Patient comfort, duration of HFNO therapy, and outcome were also recorded. The GV at 10, 20, and 30 minutes were significantly larger (p < 0.001) compared to baseline. This increase in GV was associated with a significantly increased number of peristaltic contractions and had a significant positive correlation with the HFNO flow (r = 0.541; p < 0.001). The HFNO therapy was well tolerated by most of the patients and led to a significant improvement in the vitals and blood gas parameters at 30 minutes after initiation of HFNO therapy. In adult patients with hypoxemic respiratory failure, the use of HFNO therapy produces gas leaks into the stomach leading to increased gastric volume. The gastric distension increases the peristaltic contraction and higher flows result in more distension. Ramachandran A, Bhatia P, Mohammed S, Kamal M, Chhabra S, Paliwal B. Gastric Insufflation with High Flow Nasal Oxygen Therapy in Adult Patients Admitted to Intensive Care Unit: An Observational Study. Indian J Crit Care Med 2024;28(4):393-398.

High flow nasal oxygen vs. conventional oxygen therapy over respiratory oxygenation index after esophagectomy: an observational study.

Postoperative pulmonary complications after esophagectomy still represent a matter of concern. High flow nasal cannula (HFNC) early after major abdominal and thoracic surgery has demonstrated some advantages over conventional oxygen therapy. Data about respiratory effect of HFNC after esophagectomy is scarce. The primary aim of this study is to investigate if the early use of HFNC after esophagectomy could enhance patients' postoperative respiratory oxygenation (ROX) index and, ultimately, reduce postoperative pneumonia. In this single center retrospective study all patients undergoing to esophagectomy for cancer from May 2020 to November 2022 were evaluated. Historical cohort (HC) received postoperative oxygen supplementation with Venturi mask or nasal goggles, and a cohort was put under HFNC (HFNC cohort). ROX index, blood gas analysis, radiological atelectasis score (RAS), post-operative complications' data and information on hospital stay have been collected and analyzed. Seventy-one patients were included for the final statistical analysis, 31 in the HFNC and 40 in the HC cohort. Mean age was 64±10 years and body mass index (BMI) was 26 [24-29] kg/m2. ROX index was higher in the HFNC patients than in the HC, 20.8 [16.7-25.9] vs. 14.9 [10.8-18.2] (P<0.0001). In the HFNC cohort patients, pH was higher, 7.42 [7.40-7.44] vs. 7.39 [7.37-7.43] than HC, while PaCO2 was lower in HFNC cohort compared with HC, 39 [36-41] vs. 42 [39-45] mmHg, respectively (P=0.01). RAS was similar between the two cohorts of patients, 1.5±0.98 vs. 1.4±1.04 in the HFNC and the HC cohort, respectively (P=0.611). Lower acute respiratory failure (ARF) rate was recorded among HFNC than HC cohort, 0% vs. 13% respectively, P=0.06. No difference in pneumonia frequency between two cohorts was shown. HFNC improved the ROX index after esophagectomy through significant respiratory rate reduction. This tool should be considered for early respiratory support after extubation in this category of patients, not only as a rescue therapy for ARF, but also to optimize early postoperative respiratory function. Whether this will improve patients' outcomes requires further large randomized controlled trials.

Machine learning prediction of the failure of high-flow nasal oxygen therapy in patients with acute respiratory failure

Acute respiratory failure (ARF) is a prevalent and serious condition in intensive care unit (ICU), often associated with high mortality rates. High-flow nasal oxygen (HFNO) therapy has gained popularity for treating ARF in recent years. However, there is a limited understanding of the factors that predict HFNO failure in ARF patients. This study aimed to explore early indicators of HFNO failure in ARF patients, utilizing machine learning (ML) algorithms to more accurately pinpoint individuals at elevated risk of HFNO failure. Utilizing ML algorithms, we developed seven predictive models. Their performance was evaluated using various metrics, including the area under the receiver operating characteristic curve, calibration curve, and precision recall curve. The study enrolled 700 patients, with 490 in the training group and 210 in the validation group. The overall HFNO failure rate was 14.1% among the 700 patients. The ML algorithms demonstrated robust performance in our study. This research underscores the potential of ML techniques in creating clinically relevant models for predicting HFNO outcomes in ARF patients. These models could play a pivotal role in enhancing the risk management of HFNO, leading to more patient-centered and personalized care approaches.

Trans-nasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) and its Utility in Otolaryngology, Head and Neck Surgery: A Literature Review.

High-flow nasal oxygen (HFNO) therapy is extensively used in critical care units for spontaneously breathing patients. Trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) is a method of apnoeic oxygenation with continuous nasal delivery of warmed, humidified oxygen at high-flow rates up to 70L/min. THRIVE extends the apnoeic window before desaturation occurs so that tubeless anaesthesia is possible. The advent of THRIVE has had a monumental impact on anaesthetic practice, with a diverse range of clinical applications and it has been incorporated into difficult airway guidelines. THRIVE has many applications in otolaryngology and head and neck surgery. It is used as a pre-oxygenation tool during induction in both anticipated and unanticipated difficult airway scenarios and as a method of oxygenation for tubeless anaesthesia in elective laryngotracheal and hypopharyngeal surgeries and during emergence from anaesthesia. In this scoping review of the literature, we aim to provide an overview on the utility of THRIVE in otolaryngology, including the underlying physiologic principles, current indications and limitations, and its feasibility and safety in different surgical contexts and specific population groups.

Efficiency of continuous positive airway pressure and high-flow nasal oxygen therapy in critically ill patients with COVID-19.

Critically ill patients with COVID-19 develop acute respiratory distress syndrome characterized by relatively well-preserved pulmonary compliance but severe hypoxemia. The challenge in managing such patients lies in optimizing oxygenation, which can be achieved through either high oxygen flow or noninvasive mechanical ventilation. This study was performed to compare the efficiency of two methods of noninvasive oxygen therapy: continuous positive airway pressure (CPAP) and high-flow nasal oxygen therapy (HFNO). This retrospective cohort study involved 668 patients hospitalized in the intensive care unit (ICU) of the "Sf. Apostol Andrei" Emergency Clinical Hospital, Galati, Romania from 1 April 2020 to 31 March 2021 (CPAP, n = 108; HFNO, n = 108). Mortality was significantly lower in the CPAP and HFNO groups than in the group of patients who underwent intubation and mechanical ventilation after ICU admission. Mortality in the ICU was not significantly different between the CPAP and HFNO groups. HFNO and CPAP represent efficient alternative therapies for patients with severe COVID-19 whose respiratory treatment has failed. Studies involving larger groups of patients are necessary to establish a personalized, more complex management modality for critically ill patients with COVID-19.

Comparison between nasal high-flow oxygen therapy and noninvasive ventilation on the outcome of patients with chronic interstitial lung disease complicated with acute respiratory failure

Abstract Background Interstitial lung disease (ILD) is a wide range of illnesses that damage the lung parenchyma and have varying etiologies, clinical presentations, radiographic patterns, and histological appearances. The common characteristic is the occurrence of inflammatory and fibrous changes. This work aimed to compare the clinical outcome of high-flow nasal oxygen therapy and noninvasive ventilation in patients presenting with acute exacerbation of chronic interstitial lung disease. Materials and Methods This prospective, randomized work was performed on 40 individuals with acute exacerbation of ILD. Participants were categorized into two equal groups: Group1 were treated with high-flow nasal oxygen therapy (HFNOT), aged from 27–82 years. Group 2 were treated with noninvasive ventilation (NIV), aged from 40 to 80 years. Results A substantial negative association existed among the HACOR score and ROX index as a low HACOR score and a high ROX index is predicting for success and vice versa. Mortality rate and survival are equal in both groups but HFNOT is more comfortable and better tolerated than NIV, and is also expected to maintain a better quality of life because it easily allows food intake and conversations. Conclusion HFNOT is considered to be the first noninvasive option as a noninvasive ventilator in individuals with acute exacerbation of ILD after the failure of conventional oxygen therapy with same efficacy, more tolerability, and less complication carrying the same mortality rate in comparison with NIV.

Analysis of therapeutic effects on type II respiratory failure and impact on blood gas changes: high-flow nasal oxygen therapy vs. non-invasive positive pressure ventilation

Analysis of therapeutic effects on type II respiratory failure and impact on blood gas changes: high-flow nasal oxygen therapy vs. non-invasive positive pressure ventilation

Normal saline for children with bronchiolitis: study protocol for a randomised controlled non-inferiority trial

IntroductionBronchiolitis is one of the most common reasons for hospital admissions in early childhood. As supportive treatment, some treatment guidelines suggest using nasal irrigation with normal saline (NS) to facilitate...

Personalized Noninvasive Respiratory Support in the Perioperative Setting: State of the Art and Future Perspectives.

Background: Noninvasive respiratory support (NRS), including high-flow nasal oxygen therapy (HFNOT), noninvasive ventilation (NIV) and continuous positive airway pressure (CPAP), are routinely used in the perioperative period. Objectives: This narrative review provides an overview on the perioperative use of NRS. Preoperative, intraoperative, and postoperative respiratory support is discussed, along with potential future areas of research. Results: During induction of anesthesia, in selected patients at high risk of difficult intubation, NIV is associated with improved gas exchange and reduced risk of postoperative respiratory complications. HFNOT demonstrated an improvement in oxygenation. Evidence on the intraoperative use of NRS is limited. Compared with conventional oxygenation, HFNOT is associated with a reduced risk of hypoxemia during procedural sedation, and recent data indicate a possible role for HFNOT for intraoperative apneic oxygenation in specific surgical contexts. After extubation, "preemptive" NIV and HFNOT in unselected cohorts do not affect clinical outcome. Postoperative "curative" NIV in high-risk patients and among those exhibiting signs of respiratory failure can reduce reintubation rate, especially after abdominal surgery. Data on postoperative "curative" HFNOT are limited. Conclusions: There is increasing evidence on the perioperative use of NRS. Use of NRS should be tailored based on the patient's specific characteristics and type of surgery, aimed at a personalized cost-effective approach.

Pre-oxygenation with high-flow oxygen through the nasopharyngeal airway compared to facemask on carbon dioxide clearance in emergency adults: a prospective randomized non-blinded clinical trial.

Before tracheal intubation, it is essential to provide sufficient oxygen reserve for emergency patients with full stomachs. Recent studies have demonstrated that high-flow nasal oxygen (HFNO) effectively pre-oxygenates and prolongs apneic oxygenation during tracheal intubation. Despite its effectiveness, the use of HFNO remains controversial due to concerns regarding carbon dioxide clearance. The air leakage and unknown upper airway obstruction during HFNO therapy cause reduced oxygen flow above the vocal cords, possibly weaken the carbon dioxide clearance. Patients requiring emergency surgery who had fasted < 8h and not drunk < 2h were randomly assigned to the high-flow group, who received 100% oxygen at 30-60 L/min through nasopharyngeal airway (NPA), or the mask group, who received 100% oxygen at 8 L/min. PaO2 and PaCO2 were measured immediately before pre-oxygenation (T0), anesthesia induction (T1), tracheal intubation (T2), and mechanical ventilation (T3). The gastric antrum's cross-sectional area (CSA) was measured using ultrasound technology at T0, T1, and T3. Details of complications, including hypoxemia, reflux, nasopharyngeal bleeding, postoperative pulmonary infection, postoperative nausea and vomiting (PONV), and postoperative nasopharyngeal pain, were recorded. The primary outcomes were PaCO2 measured at T1, T2, and T3. The secondary outcomes included PaO2 at T1, T2, and T3, CSA at T1 and T3, and complications happened during this trial. Pre-oxygenation was administered by high-flow oxygen through NPA (n = 58) or facemask (n = 57) to 115 patients. The mean (SD) PaCO2 was 32.3 (6.7) mmHg in the high-flow group and 34.6 (5.2) mmHg in the mask group (P = 0.045) at T1, 45.0 (5.5) mmHg and 49.4 (4.6) mmHg (P < 0.001) at T2, and 47.9 (5.1) mmHg and 52.9 (4.6) mmHg (P < 0.001) at T3, respectively. The median ([IQR] [range]) PaO2 in the high-flow and mask groups was 404.5 (329.1-458.1 [159.8-552.9]) mmHg and 358.9 (274.0-413.3 [129.0-539.1]) mmHg (P = 0.007) at T1, 343.0 (251.6-428.7 [73.9-522.1]) mmHg and 258.3 (162.5-347.5 [56.0-481.0]) mmHg (P < 0.001) at T2, and 333.5 (229.9-411.4 [60.5-492.4]) mmHg and 149.8 (87.0-246.6 [51.2-447.5]) mmHg (P < 0.001) at T3, respectively. The CSA in the high-flow and mask groups was 371.9 (287.4-557.9 [129.0-991.2]) mm2 and 386.8 (292.0-537.3 [88.3-1651.7]) mm2 at T1 (P = 0.920) and 452.6 (343.7-618.4 [161.6-988.1]) mm2 and 385.6 (306.3-562.0 [105.5-922.9]) mm2 at T3 (P = 0.173), respectively. The number (proportion) of complications in the high-flow and mask groups is shown below: hypoxemia: 1 (1.7%) vs. 9 (15.8%, P = 0.019); reflux: 0 (0%) vs. 0 (0%); nasopharyngeal bleeding: 1 (1.7%) vs. 0 (0%, P = 1.000); pulmonary infection: 4 (6.9%) vs. 3 (5.3%, P = 1.000); PONV: 4 (6.9%) vs. 4 (7.0%, P = 1.000), and nasopharyngeal pain: 0 (0%) vs. 0 (0%). Compared to facemasks, pre-oxygenation with high-flow oxygen through NPA offers improved carbon dioxide clearance and enhanced oxygenation prior to tracheal intubation in patients undergoing emergency surgery, while the risk of gastric inflation had not been ruled out. This trial was registered prospectively at the Chinese Clinical Research Registry on 26/4/2022 (Registration number: ChiCTR2200059192).

Use of veno-venous extracorporeal membrane oxygenation in a female patient with severe acute respiratory distress syndrome and peri-intubation cardiac arrest. Clinical observation

Acute respiratory distress syndrome (ARDS) is a life-threatening form of respiratory failure which can occur in people of any age. It comprises about 10 % of all admissions in intensive care units. The cornerstone of treatment of severe forms of this disorder is protective mechanical ventilation but in patients with initial hypoxia and/or hypotension tracheal intubation is associated with the risk of significant hemodynamic abnormalities. Mortality from severe forms of ARDS remains high. COVID-19 pandemic led to worldwide wider use of such techniques of respiratory support as high-flow nasal oxygen therapy and non-invasive ventilation, the necessity of which is proposed to be used as one of classifying signs of ARDS in addition to the Berlin criteria. If the respiratory therapy is ineffective, veno-venous extracorporeal membrane oxygenation is used for gaseous exchange and decreasing undesirable effects of high pressure in the respiratory pathways. The success of its application strongly depends on the optimal timing of its initialization. The performance of this technique is associated with a number of complications (hemorrhage, thrombosis, sepsis, etc.). Effective treatment of ARDS requires utilization of a large amount of resources and educated staff.

In-Line Aerosol Therapy via Nasal Cannula during Adult and Paediatric Normal, Obstructive, and Restrictive Breathing.

High-flow nasal oxygen therapy is being increasingly adopted in intensive and home care settings. The concurrent delivery of aerosolised therapeutics allows for the targeted treatment of respiratory illnesses. This study examined in-line aerosol therapy via a nasal cannula to simulated adult and paediatric models with healthy, obstructive and restrictive lung types. The Aerogen Solo vibrating mesh nebuliser was used in combination with the InspiredTM O2FLO high-flow therapy system. Representative adult and paediatric head models were connected to a breathing simulator, which replicated several different states of lung health. The aerosol delivery was quantified at the tracheal level using UV-spectrophotometry. Testing was performed at a range of supplemental gas flow rates applicable to both models. Positive end-expiratory pressure was measured pre-, during and post-nebulisation. The increases in supplemental gas flow rates resulted in a decrease in aerosol delivery, irrespective of lung health. Large tidal volumes and extended inspiratory phases were associated with the greatest aerosol delivery. Gas flow to inspiratory flow ratios of 0.29-0.5 were found to be optimum for aerosol delivery. To enhance aerosol delivery to patients receiving high-flow nasal oxygen therapy, respiratory therapists should keep supplemental gas-flow rates below the inspiratory flow of the patient.

Ultrasound Assessment of Gastric Volume in Parturients After High-flow Nasal Oxygen Therapy

(Anesth Analg. 2023;137:176–181) High-flow nasal oxygen (HFNO) therapy is a preferred method of respiratory support for pregnant women but concerns have been raised for gastric complications because of the positive airway pressure. Pregnancy causes physiological changes that can increase the risk of oxygen insufflation into the stomach, as well as the risk of aspiration. Aspiration risk can be determined by ultrasound assessment of gastric volume and antral cross-sectional area (CSA). This study was designed to assess the safety of HFNO therapy by examining changes in antral CSA and gastric volume via ultrasonography before and after HFNO administration, with a hypothesis that 20 minutes of HFNO therapy would increase gastric volume by 50%.

Ventilatory support and inflammatory peptides in hospitalised patients with COVID-19: A prospective cohort trial.

Several studies have shown that SARS-CoV-2 can induce a massive release of cytokines which contributes to disease severity and mortality. Therefore, cytokine levels in the serum may help to predict disease severity and survival in COVID-19 patients. In this prospective trial, 88 patients who were hospitalised for COVID-19 were enrolled. Blood samples for serum peptide measurements were taken at the time closest to hospitalisation, at day 5, 9 and 13 (±1). The concentrations of cytokines (IL-1α, IL-1β, IL-1RA, IL-6, L-7, L-10, IFN-γ and TNF-α), chemokines (CCL-3, CCL-4 and CCL-7) and growth factors (G-CSF, GM-CSF and VEGF) were assessed and correlated with the type of ventilation, occurrence of consolidations on imaging and the level of care. COVID-19 patients (median age 68 years, IQR 55-77) stayed in hospital between 5-171 days. Compared to patients in the general care unit, patients in the intermediate care unit (IMCU) and intensive care unit (ICU) presented significantly elevated serum IL-6 (p = 0.004) and lower IFN-γ levels (p = 0.005), respectively. The peak inspiratory pressure in ventilated patients correlated positively with IL-1RA, G-CSF and inversely with IFN-γ serum levels (all p<0.05). VEGF serum levels inversely correlated with the fraction of inspired oxygen in patients receiving high-flow nasal canula oxygen therapy (p = 0.047). No significant correlation between serum concentrations of the measured peptides and the type of ventilation, occurrence of radiological consolidations or in-hospital mortality has been observed. IL1-RA, IL-6, IFN-γ, G-CSF, CCL-7 and VEGF serum levels could prove helpful as biomarkers to assess disease severity and the need for intensive care in COVID-19 patients.

Failure of Non-Invasive Respiratory Support in Patients with SARS-CoV-2.

The objective of this study is to assess the failure of therapies with HFNO (high-flow nasal oxygen), CPAP, Bilevel, or combined therapy in patients with hypoxemic acute respiratory failure due to SARS-CoV-2 during their hospitalization. This was a retrospective and observational study of SARS-CoV-2-positive patients who required non-invasive respiratory support (NIRS) at the Reina Sofía General University Hospital of Murcia between March 2020 and May 2021. Of 7355 patients, 197 (11.8%) were included; 95 of them failed this therapy (48.3%). We found that during hospitalization in the ward, the combined therapy of HFNO and CPAP had an overall lower failure rate and the highest treatment with Bilevel (p = 0.005). In the comparison of failure in therapy without two levels of airway pressure, HFNO, CPAP, and combined therapy of HFNO with CPAP, (35.6% of patients) presented with 24.2% failure, compared to those who had two levels of pressure with Bilevel and combined therapy of HFNO with Bilevel (64.4% of patients), with 75.8% associated failure (OR: 0, 374; CI 95%: 0.203-0.688. p = 0.001). The use of NIRS during conventional hospitalization is safe and effective in patients with respiratory failure secondary to SARS-CoV-2 infection. The therapeutic strategy of Bilevel increases the probability of failure, with the combined therapy strategy of CPAP and HFNO being the most promising option.

Evaluation of Early Institution of High Flow Nasal Oxygen Therapy in Type 1 Respiratory Failure in COVID 19 Patients - An Observational Study

Evaluation of Early Institution of High Flow Nasal Oxygen Therapy in Type 1 Respiratory Failure in COVID 19 Patients - An Observational Study

The Momentum Battle in an Upper Airway During High Flow Nasal Cannula Oxygen Therapy

Abstract Two types of high flow nasal cannula (HFNC) oxygen therapy were tested using computational models of the human upper airway to investigate cannula geometry's effect on CO2 flush. Models were run with a generic HFNC geometry, two High Velocity Nasal Insufflation (HVNI) cannula geometries, and without any cannula, each for open and closed mouth patient scenarios. For the open mouth scenario, models included either an inflamed left nasal passageway or a healthy (uninflamed) left nasal passageway. With a healthy left nasal passageway and open mouth, the CO2 remaining in the airway at end-exhale was 1.88 mg and 1.84 mg for the HVNI cannulas, 2.56 mg for HFNC, and 10.0 mg for the model with no cannula. With an inflamed left nasal passageway and open mouth, the CO2 remaining was 1.97 mg, 1.95 mg, 4.24 mg, and 10.5 mg for the same sequence of therapy types. For the closed mouth models, the distinction between therapy types was negligible. It was found that the higher momentum from the HVNI cannulas created a higher resistance against the infiltration of exhaled CO2 into the upper airway. The HVNI cannulas also began flushing the airway (reducing total CO2 mass) earlier in the exhalation cycle than both the HFNC and no-cannula models. The higher resistance to expiratory flow entering the upper airway and earlier transition to flush led to HVNI therapy having the lowest values of CO2 remaining in the airway.