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.

Safety and efficacy of noninvasive ventilation for acute respiratory failure in general medical ward: a prospective cohort study

Background

Noninvasive ventilation (NIV) is recommended for use in patients with acute respiratory failure of various etiologies. However, we do not know whether the use of NIV in general medical wards is safe and effective. This study aimed to evaluate the safety and efficacy of using NIV and factors associated with NIV failure in general medical wards.

Methods

A prospective cohort study was conducted in general medical wards of the University Hospital. Adult patients with acute respiratory failure treated with NIV were enrolled. The subjects were managed by a multidisciplinary care team that was well trained in the NIV device. The primary outcome was the rate of NIV failure at 48 hours. Secondary outcomes included hospital mortality and factors associated with NIV failure.

Results

A total of 86 patients were enrolled. The mean age was 70±17 years old. The Acute Physiology and Chronic Health Evaluation (APACHE) III and the Sequential Organ Failure Assessment (SOFA) scores were 56±17 and 4±3, respectively. The most common indication of NIV use was cardiogenic pulmonary edema (34.9%). The rate of NIV failure at 48 hours and hospital mortality were 20.9% and 12.8%, respectively. The SOFA score was associated with failure of NIV at 48 hours [odds ratio (OR) 1.48, 95% confidence interval (CI): 1.16-1.89; P=0.002].

Conclusions

NIV was safe and effective on general medical wards. Cardiogenic pulmonary edema was the most common indication for the application of NIV. The SOFA score was associated with the failure of NIV at 48 hours.

Effects of 2 modes of positive pressure ventilation on respiratory mechanics and gas exchange in foals

BACKGROUND

Continuous positive airway pressure (CPAP) and pressure support ventilation (PSV) can improve respiratory mechanics and gas exchange, but different airway pressures have not been compared in foals.

HYPOTHESIS/OBJECTIVES

Assess the effect of different airway pressures during CPAP and PSV have on respiratory function in healthy foals with pharmacologically induced respiratory insufficiency. We hypothesized that increased airway pressures would improve respiratory mechanics and increased positive end-expiratory pressure (PEEP) would be associated with hypercapnia.

ANIMALS

Six healthy foals from a university teaching herd.

METHODS

A prospective, 2-phase, 2-treatment, randomized cross-over study design was used to evaluate sequential interventions in sedated foals using 2 protocols (CPAP and PSV). Outcome measures included arterial blood gases, spirometry, volumetric capnography, lung volume and aeration assessed using computed tomography (CT).

RESULTS

Sedation and dorsal recumbency were associated with significant reductions in arterial oxygen pressure (PaO₂ ), respiratory rate, and tidal volume. Continuous positive airway pressure was associated with improved PaO₂ , without concurrent hypercapnia. Volumetric capnography identified improved ventilation:perfusion (V/Q) matching and increased carbon dioxide elimination during ventilation, and spirometry identified decreased respiratory rate and increased tidal volume. Peak inspiratory pressure was moderately associated with PaO₂ and lung volume. Improved pulmonary aeration was evident in CT images, and lung volume was increased, particularly during CPAP.

CONCLUSIONS AND CLINICAL IMPORTANCE

Both CPAP and PSV improved lung mechanics and gas exchange in healthy foals with induced respiratory insufficiency.

Identifying themes to inform nursing decisions when caring for patients with acute exacerbation of chronic obstructive pulmonary disease on noninvasive ventilation: A qualitative descriptive study

Prior studies analyzing patient experience with noninvasive ventilation (NIV) found the most impactful interaction that patients remembered was with nurses, however a survey of nurses regarding the management of patients treated with NIV has shown that most nurses felt unprepared to care for these sick patients. Our qualitative descriptive study explored the current nursing experience using NIV as a treatment for acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Nine (n = 9) subject matter expert nurses practicing in a variety of clinical settings participated in semi-structured interviews. The COnsolidated criteria for REporting Qualitative research checklist was followed for interview development. Interview transcripts were subsequently analyzed using deductive thematic analysis. Themes identified from the interviews pertained to patient assessment, novice nurses' need for clinical support, team communication, and nursing education. Improving interprofessional team communication and collaboration skills, and implementing guidelines for NIV utilization were specified as essential components of NIV education for nurses. Even though the nursing role in the care of AECOPD NIV patient could be institution dependent, the themes presented in our study are useful in identifying opportunities for NIV nursing education and areas for further research. Patient or Public Contribution: Nurses served as interviewees for this study.

Esophageal Pressure Measurement in Acute Hypercapnic Respiratory Failure Due to Severe COPD Exacerbation Requiring NIV-A Pilot Safety Study

Esophageal pressure (Pes) measurements could optimise ventilator parameters in acute respiratory failure (ARF) patients requiring noninvasive ventilation (NIV). Consequently, the objectives of our study were to evaluate the safety and accuracy of applying a Pes measuring protocol in ARF patients with AECOPD under NIV in our respiratory intermediate care unit (RICU). An observational cohort study was undertaken. The negative inspiratory swing of Pes (ΔPes) was measured: in an upright/supine position in the presence/absence of NIV at D1 (day of admission), D3 (3rd day of NIV), and DoD (day of discharge). A digital filter for artefact removal was developed. We included 15 patients. The maximum values for ∆Pes were recorded at admission (mean ∆Pes 23.2 cm H2O) in the supine position. ∆Pes decreased from D1 to D3 (p < 0.05), the change being BMI-dependent (p < 0.01). The addition of NIV decreased ∆Pes at D1 and D3 (p < 0.01). The reduction of ∆Pes was more significant in the supine position at D1 (8.8 cm H2O, p < 0.01). Under NIV, ∆Pes values remained higher in the supine versus upright position. Therefore, the measurement of Pes in AECOPD patients requiring NIV can be safely done in an RICU. Under NIV, ∆Pes reduction is most significant within the first 24 h of admission.

Factors influencing the use of postoperative bilevel positive airway pressure (BiPAP) in patients undergoing adult cardiac surgery: A retrospective cohort study

BAckground and Aims

Respiratory complications are one of the biggest challenges following cardiac surgery, which can lead to hypoxia and acute respiratory failure (ARF). The aim of this study to identify the factors led to BiPAP application for postoperative respiratory complications and its effectiveness as the main outcome measures after cardiac surgery.

Methods

It was a retrospective cohort study with consecutive sampling technique. A total of 335 postcardiac surgery patients medical record was reviewed who were underwent for surgery from November 1, 2018 to November 30, 2019. 265 patients were finalized for the recruitment, five patients were excluded before the final analysis. Data of 260 patients were analyzed for compiling of results.

Results

The mean age was 59 years. 196 (75.4%) patients were males and females were 64 (24.6%). Mean weight was 72 kg and mean body mass index (BMI) 26.67 kg/m²_. BiPAP application was in 38 (14.6%) patients and significantly high in with high BMI, (p < 0.05). There are significant associations of BiPAP application patients with COPD (p < 0.05). Patients with positive fluid balance, cardiac dysfunction, and required inotropic support were significantly associated with BiPAP need (p < 0.05), respectively.

Conclusion

BiPAP is effective to treat ARF and other respiratory complications after adult cardiac surgeries. High BMI, atelectasis, and pneumonia are also the independent factors causing ARF. BiPAP can be a successful tool for preventing the adverse effects of postoperative pulmonary complications after cardiac surgery.

Alveolar Ventilation-Targeted Versus Spontaneous/Timed Mode for Home Noninvasive Ventilation in Amyotrophic Lateral Sclerosis

BACKGROUND

Home noninvasive ventilation (NIV) is increasingly used in amyotrophic lateral sclerosis (ALS) to improve symptoms and survival. Our primary objective was to compare intelligent volume-assured pressure support (iVAPS) versus spontaneous/timed (S/T) modes regarding time to first change in ventilator parameters and the number of interventions over 6 months in subjects with ALS in a respiratory therapist (RT)-led program.

METHODS

In this study, 30 subjects with ALS meeting criteria for NIV initiation were randomized to iVAPS or S/T. NIV was initiated using standardized protocols targeting optimal tidal volume and comfort in a daytime session. Download data were recorded at 1 week and 1 and 6 months. Any changes in ventilator parameters were recorded.

RESULTS

Of the 30 subjects, 56.7% had bulbar onset ALS, 8 died, and 11 in each group completed the study. Median time to first parameter change was 33.5 (interquartile range [IQR] 7.7-96.0) d versus 41.0 (IQR 12.5-216.5) d for iVAPS versus S/T groups, respectively, (P = .48). The average number of RT interventions was similar between groups (1.1 ± 1.1 vs 0.9 ± 0.9 at 1 month, P = .72; 2.4 ± 2.1 vs 2.4 ± 2.3 at 6 months, P = .95, for iVAPS vs S/T, respectively). Adherence was significantly lower with iVAPS than S/T at 1 week but not at 1 or 6 months. Download parameters were similar between groups at 1 week and 6 months except for higher residual apnea-hypopnea index (AHI) and less spontaneously triggered breaths with iVAPS at 6 months.

CONCLUSIONS

The time to first change of parameters and the number of interventions at 6 months from NIV initiation were similar for the iVAPS and S/T modes in subjects with ALS. With iVAPS, adherence was lower transiently at NIV initiation, and the residual AHI was higher at 6 months. Alveolar ventilation-targeted NIV may require a longer adaptation period and result in greater upper-airway instability predominantly in patients with bulbar ALS.

Noninvasive ventilation in patients with COVID-19 from the perspective of the risk of contamination: a narrative review

INTRODUCTION

noninvasive ventilation (NIV) can be a useful resource to treat acute respiratory failure (ARF), which occurs in patients with COVID-19. However, it is important to consider that there are still no clinical studies that have verified the safety of its use in increase of contamination.

AREAS COVERED

Given the potential benefits and simultaneous concerns over the use of NIV in patients with COVID-19, further inquiry is necessary to reach a clinical consensus and provide recommendations for safe use, avoiding contamination. In this context, this narrative review, which included articles published in the Embase, SciELO, PEDro, PubMed and Cochrane up to August 2021, is focused to evaluate available studies related to interfaces, types of circuits, recommended filters, cares for the environment and protective factors for NIV use in patients with COVID-19.

EXPERT OPINION

The studies analyzed recommend that the use of NIV can be safe: 1) with equipment that allows the use of the helmet as a safer interface; 2) with double circuit and antimicrobial filter in the expiratory branch; 3) in an environment that allows negative pressure, reducing the dispersion of aerosol particles in the environment; 4) the health team must use the recommended PPE to avoid contamination.

Randomized Controlled Trial of a Novel Communication Device Assessed During Noninvasive Ventilation Therapy

BACKGROUND

Noninvasive ventilation (NIV), a form of positive airway pressure (PAP) therapy, is the standard of care for various forms of acute respiratory failure (ARF). Communication impairment is a side effect of NIV, impedes patient care, contributes to distress and intolerance, and potentially increases intubation rates. This study aimed to evaluate communication impairment during CPAP therapy and demonstrate communication device improvement with a standardized protocol.

RESEARCH QUESTION

How does an oronasal mask affect communication intelligibility? How does use of an NIV communication device change this communication intelligibility?

STUDY DESIGN AND METHODS

A single-center randomized controlled trial (36 outpatients with OSA on CPAP therapy) assessed exposure to CPAP 10 cm H₂O and PAP communication devices (SPEAX, Ataia Medical). Communication impairment was evaluated by reading selected words and sentences for partners to record and were tabulated as %words correct. Each outpatient-partner pair performed three assessments: (1) baseline (conversing normally), (2) mask baseline (conversing with PAP), and (3) randomized to functioning device (conversing with PAP and device) or sham device. After each stage, both outpatients and partners completed Likert surveys regarding perceived intelligibility and comfort.

RESULTS

While conversing with PAP, word and sentence intelligibility decreased relatively by 52% (87% vs 41%) and relatively by 57% (94% vs 40%), respectively, compared with normal conversation. Word and sentence intelligibility in the intervention arm increased relatively by 75% (35% vs 61%; P < .001) and by 126% (33% vs 76%; P < .001) higher than the control arm, respectively. The device improved outpatient-perceived PAP comfort relatively by 233% (15% vs 50%, P = .042) and partner-perceived comfort by relatively 245% (20% vs 69%, P = .0074).

INTERPRETATION

Use of this PAP communication device significantly improves both intelligibility and comfort. This is one of the first studies quantifying communication impairment during PAP delivery.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03795753; URL: www.clinicaltrials.gov.

Effect of high-flow nasal cannula versus conventional oxygen therapy and non-invasive ventilation for preventing reintubation: a Bayesian network meta-analysis and systematic review

Background

Adequate respiratory support can improve clinical outcomes in patients who are ready for weaning from a ventilator. We aimed to investigate the efficacy of respiratory methods in adults undergoing planned extubation using a Bayesian network meta-analysis.

Methods

We searched PubMed, Embase, and ClinicalTrials.gov for unpublished and ongoing trials up to November 2019 for randomized controlled trials (RCTs) published in English that compared conventional oxygen therapy (COT), a high-flow nasal cannula (HFNC), and noninvasive ventilation (NIV) for post-extubation respiratory support. Screening of citations, study selection, data extraction, and assessment of risk were performed independently by two authors. The primary outcome was the reintubation rate.

Results

Twenty-two studies (4,218 patients) were included in our meta-analysis. Extubated patients supported with NIV had a significantly lower incidence of reintubation than those supported with COT [odds ratio (OR): 0.63, 95% confidence interval (CI): 0.42, 0.89]. However, there was no significant difference in the reintubation rate between the HFNC and NIV, and HFNC and COT groups (OR: 1.05, 95% CI: 0.60, 1.81; OR: 0.60, 95% CI: 0.33, 1.02, respectively). HFNC and NIV reduced the incidence of hospital-acquired pneumonia (HAP) (OR: 0.50, 95% CI: 0.25, 0.93; OR: 0.55, 95% CI: 0.27, 0.87, respectively) and post-extubation acute respiratory failure (ARF) (OR: 0.35, 95% CI: 0.14, 0.89; OR: 0.31, 95% CI: 0.14, 0.63, respectively) compared with COT. There was no significant difference in a decreased incidence of HAP (OR: 1.1, 95% CI: 0.56, 1.8) or post-extubation ARF (OR: 0.87, 95% CI: 0.33, 2.1) between NIV and HFNC. There were also no significant differences in improvements in other clinical outcomes, including intensive care unit (ICU) and hospital mortality and the length of stay (LOS) between NIV and HFNC.

Conclusions

NIV reduces the reintubation rate in adult patients undergoing planned extubation compared with COT and HFNC.

A Review on Non-invasive Respiratory Support for Management of Respiratory Distress in Extremely Preterm Infants

Majority of extremely preterm infants require positive pressure ventilatory support at the time of delivery or during the transitional period. Most of these infants present with respiratory distress (RD) and continue to require significant respiratory support in the neonatal intensive care unit (NICU). Bronchopulmonary dysplasia (BPD) remains as one of the major morbidities among survivors of the extremely preterm infants. BPD is associated with long-term adverse pulmonary and neurological outcomes. Invasive mechanical ventilation (IMV) and supplemental oxygen are two major risk factors for the development of BPD. Non-invasive ventilation (NIV) has been shown to decrease the need for IMV and reduce the risk of BPD when compared to IMV. This article reviews respiratory management with current NIV support strategies in extremely preterm infants both in delivery room as well as in the NICU and discusses the evidence to support commonly used NIV modes including nasal continuous positive airway pressure (NCPAP), nasal intermittent positive pressure ventilation (NIPPV), bi-level positive pressure (BI-PAP), high flow nasal cannula (HFNC), and newer NIV strategies currently being studied including, nasal high frequency ventilation (NHFV) and non-invasive neutrally adjusted ventilatory assist (NIV-NAVA). Randomized, clinical trials have shown that early NIPPV is superior to NCPAP to decrease the need for intubation and IMV in preterm infants with RD. It is also important to understand that selection of the device used to deliver NIPPV has a significant impact on its success. Ventilator generated NIPPV results in significantly lower rates of extubation failures when compared to Bi-PAP. Future studies should address synchronized NIPPV including NIV-NAVA and early rescue use of NHFV in the respiratory management of extremely preterm infants.

Respiratory management of acute exacerbation of interstitial pneumonia using high-flow nasal cannula oxygen therapy: a single center cohort study

Background

The role of high-flow nasal cannula oxygen therapy (HFNC) in respiratory management of acute exacerbation of interstitial pneumonia (AE-IP) is unknown.

Methods

We retrospectively reviewed patients with AE-IP who were admitted to our hospital from June 2009 - May 2015 and compared mortality, complications, sedatives and analgesia use, and oral intake between cohorts before (pre-HFNC: June 2009 - May 2012) and after (post-HFNC: June 2012 - May 2015) the introduction of HFNC. In the pre-HFNC cohort, standard oxygen therapy, noninvasive ventilation (NIV), and invasive mechanical ventilation (IMV) were used for respiratory management of AE-IP. In the post-HFNC cohort, HFNC was also used as an alternative to NIV in patients (I) who had refused NIV; (II) unable to cooperate, (III) intolerant to NIV, or (IV) who improved in respiratory parameters after NIV treatment for weaning.

Results

Fifty-three pre-HFNC patients and 43 post-HFNC patients were enrolled. Neither the baseline characteristics at admission nor the major pharmacotherapy for AE-IP differed between the two cohorts. Twenty-eight (52.8%) patients and 19 (44.2%) patients required any respiratory support, in pre- and post-HFNC cohort, respectively (P=0.40). After introduction of HFNC, it was used in 40% of the patients who required respiratory support and NIV use was significantly reduced from 49.1% to 16.3% (P<0.001). The post-HFNC cohort had significantly lower in-hospital mortality than the pre-HFNC cohort (27.9% vs. 49.1%, P=0.04). The incidence of complications was not significantly different between the two cohorts. The use of sedoanalgesia during respiratory support and the number of patients who discontinued oral intake for >24 hours were decreased after the introduction of HFNC (78.6% vs. 31.6%, P<0.001; 52.8% vs. 23.3%, P=0.003).

Conclusions

HFNC might be a feasible option in respiratory management of AE-IP.

Risk factors for noninvasive ventilation failure in patients with post-extubation acute respiratory failure after cardiac surgery

Background

The effect of noninvasive ventilation (NIV) in patients with acute respiratory failure (ARF) after cardiac surgery is controversial. This study identified the feasibility of NIV and assessed the risk factors of NIV failure in patients with ARF after cardiac surgery.

Methods

We retrospectively reviewed data from 112 patients with ARF requiring NIV and categorized them into the NIV failure and success groups. Patient data were extracted for further analysis, the primary outcomes were the need for endotracheal intubation and NIV-related in-hospital mortality. The risk factors for NIV failure in patients with post-extubation ARF was analyzed.

Results

The median time from extubation to NIV was 11 hours. No difference in the EuroSCORE existed between the two groups. NIV failed in 38.4% of the patients. The NIV failure group had a higher in-hospital mortality and stay at the longer intensive care unit (ICU). Most cases of NIV failure occurred within 1-48 hours of the treatment. The main causes of early NIV failure were a weak cough reflex and/or excessive secretions and hemodynamic instability. A Sequential Organ Failure Assessment (SOFA) score ≥10.5, vasoactive-inotropic score ≥6, and pneumonia were predictors of NIV failure, whereas a body mass index (BMI) ≥25.0 kg/m² predicted NIV success.

Conclusions

NIV was effective in the study population. Multiple organ dysfunction, pneumonia, and significant inotropic drug support before NIV were associated with NIV failure, whereas a BMI ≥25 kg/m² was a predictor of NIV success.

Use of Noninvasive Ventilation During Feeding Tube Placement

Parenteral nutrition is indicated in amyotrophic lateral sclerosis (ALS) when dysphagia, loss of appetite, and difficulty protecting the airways cause malnutrition, severe weight loss, dehydration, and increased risk of aspiration pneumonia. The aim of this review is to compare percutaneous endoscopic gastrostomy (PEG), radiologically inserted G-tube (RIG), and percutaneous radiologic gastrostomy (PRG) in patients with ALS, performed with or without noninvasive ventilation (NIV). We searched PubMed, MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), the EBSCO Online Research Database, and Scopus up to December 2015. A priori selection included all randomized controlled trials (RCTs), quasi-randomized trials, and prospective and retrospective studies. The primary outcome was 30-d survival. We found no RCTs or quasi-RCTs. Seven studies about the implementation of the PEG/RIG procedure during the use of NIV and 5 studies without NIV were included. In another study of 59 subjects undergoing open gastrostomy, all with vital capacity < 30% of normal, 18 of whom were dependent on continuous NIV at full ventilatory support settings, there were no respiratory complications. Thus, the use of NIV during the implementation of these procedures, especially when used at full ventilatory support settings of pressure preset 18-25 cm H₂O, can support alveolar ventilation before, during, and after the procedures and prevent respiratory complications. The procedures investigated appear equivalent, but the methodological quality of the studies could be improved. Possible benefits with regard to nutrition parameters, quality of life, and psychological features need to be further investigated.

High-flow nasal oxygen therapy and noninvasive ventilation in the management of acute hypoxemic respiratory failure

High-flow nasal cannula (HFNC) oxygen therapy is a recent technique delivering a high flow of heated and humidified gas. HFNC is simpler to use and apply than noninvasive ventilation (NIV) and appears to be a good alternative treatment for hypoxemic acute respiratory failure (ARF). HFNC is better tolerated than NIV, delivers high fraction of inspired oxygen (FiO₂), generates a low level of positive pressure and provides washout of dead space in the upper airways, thereby improving mechanical pulmonary properties and unloading inspiratory muscles during ARF. A recent multicenter randomized controlled trial showed benefits of HFNC concerning mortality and intubation in severe patients with hypoxemic ARF. In management of patients with hypoxemic ARF, NIV results have been conflicting. Despite improved oxygenation, NIV delivered with face mask may generate high tidal volumes and subsequent ventilator-induced lung injury. An approach applying NIV with a helmet, high levels of positive end-expiratory pressure (PEEP) and low pressure support (PS) levels seems to open new opportunities in patients with hypoxemic ARF. However, a large-scale randomized controlled study is needed to assess and compare this approach with HFNC.

Noninvasive Ventilation in Mustard Airway Diseases

BACKGROUND

Noninvasive ventilation (NIV) has been shown to improve numerous clinical measures in subjects with COPD, including gas exchange, exercise tolerance, dyspnea, hospitalizations, health-related quality of life (HRQOL), and functional status. Although useful for classical COPD, NIV has not been validated specifically as a treatment option for mustard airway disease. Our aim was to assess the efficacy of NIV in subjects with severe mustard airway disease.

METHODS

This study was performed over the course of 12 months on 20 subjects with severe mustard airway disease (Global Initiative for Chronic Obstructive Lung Disease criteria). Subjects were selected from the pulmonary clinic of Baqiyatallah Hospital in Tehran, Iran. Body mass index, lung function, dyspnea, exercise tolerance, HRQOL, sleep quality, and hospitalization measures were assessed before and after NIV treatment.

RESULTS

NIV improved HRQOL (P = .03) and sleep quality (P = .06) in very severe subjects and reduced hospitalizations (P = .003) and exacerbations (P = .01) in severe subjects. Chest imaging studies showed that these subjects had heterogeneous airway disease, the main finding of which was bronchiolitis obliterans.

CONCLUSIONS

NIV can be used as an effective new palliative method in the treatment of mustard airway disorders. Subjects with very severe and severe disease benefitted differently from NIV.

Efficient Nose-to-Lung (N2L) Aerosol Delivery with a Dry Powder Inhaler

PURPOSE

Delivering aerosols to the lungs through the nasal route has a number of advantages, but its use has been limited by high depositional loss in the extrathoracic airways. The objective of this study was to evaluate the nose-to-lung (N2L) delivery of excipient enhanced growth (EEG) formulation aerosols generated with a new inline dry powder inhaler (DPI). The device was also adapted to enable aerosol delivery to a patient simultaneously receiving respiratory support from high flow nasal cannula (HFNC) therapy.

METHODS

The inhaler delivered the antibiotic ciprofloxacin, which was formulated as submicrometer combination particles containing a hygroscopic excipient prepared by spray-drying. Nose-to-lung delivery was assessed using in vitro and computational fluid dynamics (CFD) methods in an airway model that continued through the upper tracheobronchial region.

RESULTS

The best performing device contained a 2.3 mm flow control orifice and a 3D rod array with a 3-4-3 rod pattern. Based on in vitro experiments, the emitted dose from the streamlined nasal cannula had a fine particle fraction <5 μm of 95.9% and mass median aerodynamic diameter of 1.4 μm, which was considered ideal for nose-to-lung EEG delivery. With the 2.3-343 device, condensational growth in the airways increased the aerosol size to 2.5-2.7 μm and extrathoracic deposition was <10%. CFD results closely matched the in vitro experiments and predicted that nasal deposition was <2%.

CONCLUSIONS

The developed DPI produced high efficiency aerosolization with significant size increase of the aerosol within the airways that can be used to enable nose-to-lung delivery and aerosol administration during HFNC therapy.