Real-life evaluation of NIV to CPAP switch in patients with chronic respiratory failure. A case control study.

BACKGROUND: Non-invasive ventilation (NIV) is a standard of care for hypercapnic chronic respiratory failure (CRF). Obstructive sleep apnea syndrome (OSA) frequently contributes to hypoventilation in CRF patients. CPAP improves hypercapnia in selected COPD and obese patients, like NIV. We aimed to describe the profile of patients switching from NIV to CPAP in a cohort of patients on long-term ventilation and to identify the factors associated with a successful switch. METHODS: In this case-control study, 88 consecutive patients who were candidates for a NIV-CPAP switch were compared with 266 controls among 394 ventilated patients treated at the Dijon University Hospital between 2015 and 2020. They followed a standardized protocol including a poly(somno)graphy recorded after NIV withdrawal for three nights. CPAP trial was performed if severe OSA was confirmed. Patients were checked for recurrent hypoventilation after 1 and 23[14-46] nights under CPAP. RESULTS: Patients were 53% males, median age 65 [56-74] years, and median BMI 34 [25-38.5] kg/m2. Sixty four percent of patients were safely switched and remained on long-term CPAP. In multivariate analysis, the probability of a NIV-CPAP switch was correlated to older age (OR: 1.3 [1.01-1.06]), BMI (OR: 1.7 [1.03-1.12]), CRF etiology (OR for COPD: 20.37 [4.2-98,72], OR for obesity: 7.31 [1.58-33.74]), circumstances of NIV initiation (OR for acute exacerbation: 11.64 [2.03-66.62]), lower pressure support (OR: 0.90 [0.73-0.92]), lower baseline PaCO2 (OR: 0.85 [0.80-0.91]) and lower compliance (OR: 0.76 [0.64-0.90]). Among 72 patients who went home under CPAP, pressure support level was the only factor associated with the outcome of the NIV-CPAP switch, even after adjustment for BMI and age (p=0.01) with a non-linear correlation. Etiology of chronic respiratory failure, age, BMI, baseline PaCO2, circumstances of NIV initiation, time under home NIV or NIV compliance were not predictive of the outcome of the NIV-CPAP switch. CONCLUSIONS: A NIV-CPAP switch is possible in real life conditions in stable obese and COPD patients with underlying OSA.

Measurement of thoraco-abdominal synchrony using respiratory inductance plethysmography: technical aspects and a proposal to overcome its limitations.

BACKGROUND: Thoraco-abdominal asynchrony (TAA) is usually assessed by respiratory inductance plethysmography. The main parameter used for its assessment is the calculation of the phase angle based on Lissajous plots. However, there are some mathematical limitations to its use. RESEARCH DESIGN AND METHODS: Sequences of five breaths were selected from a) normal subjects, b) COPD patients, both at rest and during exercise, and c) patients with obstructive apnea syndrome. Automated analysis was performed calculating phase angle, loop rotation (clockwise or counterclockwise), global phase delay and loop area. TAA severity was estimated quantitatively and in subgroups. RESULTS: 2290 cycles were analyzed (55% clockwise rotation). Phase angle ranged from -86.90 to + 88.4 degrees, while global phase delay ranged from -179.75 to + 178.54. Despite a good correlation with global phase delay (p < 0.01, ANOVA test), phase angle and loop area were not able to correctly classify breaths with severe deviation and paradoxical movements (p=ns, Bonferroni post hoc test). CONCLUSIONS: Global phase delay covers the whole spectrum of TAA situations in a single value. It may be a relevant parameter for diagnosis and follow-up of clinical conditions leading to TAA. CLINICAL TRIAL REGISTRATION: The trial from which the traces were obtained was registered at ClinicalTrials.gov ;(identifier: NCT04597606).

Is COVID-19 Infection a Multiorganic Disease? Focus on Extrapulmonary Involvement of SARS-CoV-2.

First described in December 2019 in Wuhan (China), COVID-19 disease rapidly spread worldwide, constituting the biggest pandemic in the last 100 years. Even if SARS-CoV-2, the agent responsible for COVID-19, is mainly associated with pulmonary injury, evidence is growing that this virus can affect many organs, including the heart and vascular endothelial cells, and cause haemostasis, CNS, and kidney and gastrointestinal tract abnormalities that can impact in the disease course and prognosis. In fact, COVID-19 may affect almost all the organs. Hence, SARS-CoV-2 is essentially a systemic infection that can present a large number of clinical manifestations, and it is variable in distribution and severity, which means it is potentially life-threatening. The goal of this comprehensive review paper in the series is to give an overview of non-pulmonary involvement in COVID-19, with a special focus on underlying pathophysiological mechanisms and clinical presentation.

Residual upper airway obstruction during nocturnal noninvasive ventilation despite high positive expiratory pressure. Impact of oronasal mask to nasal mask switch.

BACKGROUND: Nasal mask (NM) and oronasal masks (OM) can be used to provide noninvasive ventilation (NIV). Recent studies suggested that OM is the most used interface and that there is no difference in efficacy or in tolerance between OM and NM for chronic use. However, studies focusing on video laryngoscopy underlined the impact of OM in residual upper airway obstruction (UAO) under NIV. We sought to assess the real-life practice of switching from OM to NM when UAO events persist despite high EPAP levels. METHODS: In an open-label single center prospective cohort study, data from files and full night polysomnography on NM and OM were collected for patients wearing OM and presenting an UAO index ≥15/h despite an EPAP level ≥ 10 cmH20. RESULTS: Forty-four patients were included in the study. In 31 patients (74 %), switching to a NM reduced UAOi to ≥10/h. Interestingly, 92 % of these patients still had NM at 3 to 12 months of follow-up. Switching to a NM was also associated with a trend in paCO2 reduction and significant improvements in Epworth, sleep quality and NIV compliance. Successful interface switching was significantly associated with female gender, and a trend was observed in non-smokers. CONCLUSION: As for CPAP, switching to a NM improved NIV efficacy in a selected group of patients presenting residual UAO events despite high EPAP levels. Additionally, this switch has an impact on compliance and subjective sleepiness. Thus, in patients with persisting UAO on OM, switching to a NM could be a first-line intervention before considering further investigation such as polygraphy or video laryngoscopy. We also derive an algorithm for mask allocation and adaptation in acute and chronic NIV use.

Home NIV treatment quality in patients with chronic respiratory failure having participated to the French nationwide telemonitoring experimental program (The TELVENT study).

BACKGROUND: The ETAPES program is a national telemedicine experiment conducted in France between 2018 and 2023 to investigate whether home non-invasive ventilation (NIV) telemonitoring improves healthcare pathways in patients with chronic respiratory failure (CRF) and impacts healthcare organization. The program provides a combination of therapeutic education and NIV telemonitoring with data processed by an algorithm generating alerts. The TELVENT study objective was to analyze the evolution of ventilation quality in patients included in the ETAPES program. METHODS: Multicentric cohort study on patients undergoing long-term NIV included in the ETAPES program between September 2018 and December 2020 and who did not refuse the use of their data for this research. Data were obtained from homecare provider databases. The primary endpoint was to attain successful NIV treatment, which was determined by a combination of daily NIV usage for > 4 h per day, low leaks, and a low apnea-hypopnea index (AHI) identified by the NIV device. Respiratory disability was assessed using the DIRECT questionnaire. RESULTS: 329 patients were included in the study of which 145 had COPD and 83 had started NIV and ETAPES within one-month delay. Approximately 25% of patients did not achieve the criteria for successful NIV at ETAPES entry. The proportion of patients with successful NIV treatment increased to 86.8% at six months (p = 0.003, Cochran-Armitage trend test) regardless of NIV history and continued to increase at 12 months in newly equipped NIV patients (93.8%, at month 12, p = 0.0026 for trend test). Over time, a significant increase in NIV use and compliance was observed, while AHI significantly decreased in the overall population. No significant decrease was observed for non-intentional leaks. Approximately 4.9 alerts were generated per patient per 6 months. Their number and type (low NIV use, high AHI or leaks) differed among patients based on their NIV history. Respiratory disability score decreased over time compared with baseline. CONCLUSION: The TELVENT study highlights the importance of remote NIV monitoring to rapidly identify patients with unsuccessful ventilation. The combination of remote monitoring and therapeutic education may improve the quality of home NIV, especially in the first months of treatment.

Outcomes in Patients with Acute Myocardial Infarction and Known Sleep Apnea: A Nationwide Analysis.

Background. Sleep apnea (SA) is a common breathing disorder characterized by repetitive upper airway narrowing and closure. Although SA has been demonstrated to be an independent risk factor for all-cause mortality, the direct contribution of SA to worse cardiovascular prognosis may be difficult to evaluate, and its independent association with the different types of cardiovascular outcomes may be debated, particularly in the context of patients with acute myocardial infarction (AMI). The aim of this study was to assess the impact of known SA on the outcomes of hospitalized patients who have had an AMI by analyzing 10-year data collected from a national registry. Methods. This longitudinal cohort study was based on the national hospitalization database that covers hospital care for the entire French population, including all patients admitted with AMI from January 2010 to June 2019. The clinical outcomes for the analysis were as follows: all-cause death, cardiovascular death, ischemic stroke, new-onset atrial fibrillation (FA), and re-hospitalization for heart failure (HF). Results. Among the 797,212 patients who presented with an AMI (528,351 men and 268,861 women), 37,075 (4.7%) had documented SA. During follow-up (mean [SD] 1.8 [2.4] years, median [interquartile range] 0.7 [0.1-3.1] years), 163,845 deaths (of which 85,649 were cardiovascular deaths), 20,168 ischemic strokes, 58,498 new-onset AF, and 92,381 rehospitalizations due to HF were recorded. Patients with known SA had a worse prognosis in the short and medium term, but after adjusting for all covariables, SA was only independently associated with a higher risk of rehospitalization for HF and new-onset AF in men and women. Conclusion. Data from our large nationwide analysis confirm that known SA is associated with poor cardiovascular outcomes in patients who have had an AMI. However, this impact is tem-pered when the model is adjusted for age, cardiovascular risk, or other covariables. Further studies need to be conducted to assess the independent impact of SA on the prognosis of patients with AMI.

Auto-adjusted versus fixed positive airway pressure in patients with severe OSA: A large randomized controlled trial.

BACKGROUND AND OBJECTIVE: Continuous positive airway pressure (CPAP) in the treatment of severe obstructive sleep apnoea (OSA) can be used in fixed CPAP or auto-adjusted (APAP) mode. The aim of this prospective randomized controlled clinical study was to evaluate the 3 month-efficacy of CPAP used either in fixed CPAP or APAP mode. METHODS: Eight hundred one patients with severe OSA were included in twenty-two French centres. After 7 days during which all patients were treated with APAP to determine the effective pressure level and its variability, 353 and 351 patients were respectively randomized in the fixed CPAP group and APAP group. After 3 months of treatment, 308 patients in each group were analysed. RESULTS: There was no difference between the two groups in terms of efficacy whatever the level of efficient pressure and pressure variability (p = 0.41). Exactly, 219 of 308 patients (71.1%) in the fixed CPAP group and 212 of 308 (68.8%) in the APAP group (p = 0.49) demonstrated residual apnoea hypopnoea index (AHI) <10/h and Epworth Score <11. Tolerance and adherence were also identical with a similar effect on quality of life and blood pressure evaluation. CONCLUSION: The two CPAP modes, fixed CPAP and APAP, were equally effective and tolerated in severe OSA patients.

Ventilación no invasiva en sala de hospitalización general / Non-Invasive Ventilation in a Regular Hospital Ward

Introducción: La experiencia clínica ha permitido la ventilación no invasiva fuera de unidades críticas. Describimos el perfil clínico y evolución de pacientes que recibieron ventilación no invasiva en sala general. Material y métodos: Estudio retrospectivo en pacientes con soporte ventilatorio du rante un año en un hospital general. Resultados: Se utilizó ventilación no invasiva en 43 pacientes, 67,4% con hipercap nia. La relación hombre/mujer fue 1:1. La edad y el IMC fueron 68,3 ± 12,4 años y 30,1 ± 12,3 kg/m2 y los diagnósticos principales, enfermedad pulmonar obstructiva crónica, enfermedad neuromuscular y obesidad-hipoventilación. Un tercio inició la ventilación no invasiva en la unidad de cuidados intensivos, y dos tercios usaban ventilación no invasiva en domicilio antes del ingreso por exacerbación de la enfermedad pulmonar obstructiva crónica (39,5%) o progresión de la enfermedad (14%). La estancia hospi talaria fue 12,1 ± 7 d (14 ± 9 en supervivientes y 5,7 ± 3 en pacientes fallecidos). La gasometría arterial al ingreso reveló PaCO2: 52,7 ± 13,7 mmHg; PaO2: 72,2 ± 16,2 mmHg y pH de 7,36 ± 0,08. Se halló pH < 7,35 en el 18,6% y PaCO2 > 45 en el 57,4%. La PaCO2 al alta fue menor (46,1 ± 4,6; p > 0,05). El modo ST se utilizó en 34 (79%) pacientes. El período de ventilación fue 12,7 ± 10,2 días con uso de 6,9 ± 3,1 h/d. Un tercio recibió cuidados paliativos (13,9% de mortalidad). Tres pacientes (7%) fueron transferidos a la unidad de cuidados intensivos por deterioro clínico y treinta y cinco egresaron con ventilación crónica (94,6%). Conclusiones: Hubo escasas transferencias a la unidad de cuidados intensivos. La mortalidad hospitalaria fue baja y los que fallecieron tenían instrucciones anticipadas.

Introduction: Clinical experience has allowed the use of non-invasive ventilation out side the acute-care setting. We describe the clinical profile and evolution of patients who received non-invasive ventilation in a regular ward. Materials and methods: Retrospective study in patients with ventilatory support for one year in a general hospital. Results: Non-invasive ventilation was delivered to 43 patients, 67.4% of which had hy percapnia. The male/female ratio was 1:1. Age and BMI (Body Mass Index) were 68.3 ± 12.4 years and 30.1 ± 12.3 kg/m2, and the main diagnoses were chronic obstructive pulmonary disease, neuromuscular disease and obesity-hypoventilation. One third of patients began non-invasive ventilation in the Intensive Care Unit, and two thirds had been using non-invasive ventilation at their homes before being admitted with exacerba tion of chronic obstructive pulmonary disease (39.5%) or disease progression (14%). Hospital length of stay was 12.1 ± 7 d (14 ± 9 in survivors and 5.7 ± 3 in deceased patients). Arterial blood gas analysis on admission showed: PaCO2 (partial pressure of arterial carbon dioxide), 52.7 ± 13.7 mmHg; PaO2 (partial pressure of arterial oxygen), 72.2 ± 16.2 mmHg, and pH, 7.36 ± 0.08. A pH level < 7.35 was found in 18.6%, and PaCO2 > 45 in 57.4%. PaCO2 values upon discharge were lower (46.1 ± 4.6; p > 0.05). The ST (spontaneous-timed) mode was used in 34 patients (79%). The ventilation period was 12.7 ± 10.2 days, using 6.9 ± 3.1 h/d. One third of patients received palliative care (13.9% of mortality). Three patients (7%) were transferred to the Intensive Care Unit due to clinical decline, and thirty-five were discharged with chronic ventilation (94.6%). Conclusions: there were few referrals to the Intensive Care Unit. Hospital mortality was low, and patients who died had advance directives.

Long-Term Noninvasive Ventilation in Chronic Obstructive Pulmonary Disease: Association between Clinical Phenotypes and Survival.

BACKGROUND: Long-term noninvasive ventilation (LTNIV) is widely used in patients with chronic hypercapnic respiratory failure (CHRF) related to COPD. Prognosis of these patients is however poor and heterogenous. RESEARCH QUESTION: In COPD patients under LTNIV for CHRF, is it possible to identify specific phenotypes which are predictive of probability of pursuing NIV and survival? STUDY DESIGN AND METHODS: A latent class analysis was performed in a COPD population under LTNIV included in a comprehensive database of patients in the Geneva Lake area, to determine clinically relevant phenotypes. The observation period of this subgroup of COPD was extended to allow assessment of survival and/or pursuit of NIV for at least 2 years after inclusion. A logistic regression was conducted to generate an equation accurately attributing an individual patient to a defined phenotype. The identified phenotypes were compared on a series of relevant variables, as well as for probability of pursuing NIV or survival. A competitive risk analysis allowed to distinguish death from other causes of cessation of NIV. RESULTS: Two phenotypes were identified: a "respiratory COPD" profile with very severe airway obstruction, a low or normal body mass index, and a low prevalence of comorbidities and a "systemic COPD" profile of obese COPDs with moderate airway obstruction and a high rate of cardiovascular and metabolic comorbidities. The logistic regression correctly classified 95.7% of patients studied. Probability of pursuing NIV and survival were significantly related to these phenotypes, with a poorer prognosis for "respiratory COPD." Probability of death 5 years after implementing NIV was 22.3% (95% CI: 15.4-32.2) for "systemic COPD" versus 47.2% (37.4-59.6) for "respiratory COPD" (p = 0.001). CONCLUSION: The two distinct phenotypes of COPD under LTNIV for CHRF identified appear to be strongly related to prognosis and require further validation in other cohort studies.

Growth of home respiratory equipment from 2006 to 2019 and cost control by health policies.

BACKGROUND: Home respiratory equipment (HRE) designed for the management of chronic respiratory failure includes oxygen therapy (O2), noninvasive ventilation (NIV) and mechanical insufflation-exsufflation (MI-E). The growth of the number of patients treated by HRE, the prevalence and the associated costs in France have not been determined. METHODS: The French open access national health insurance aggregated data was used to estimate the evolution of theses parameters from 2006 to 2019. RESULTS: The number of patients treated by HRE increased by 117% between 2006 and 2019, reaching a total of 245,896 patients (367/100,000). Prescriptions for O2, NIV, and MI-E increased by 88%, 189% and 162%, respectively. In 2019, 139,323 patients received long-term home O2 alone (208/100,000) with a 13% decrease for liquid O2 compared to a 44% increase for O2 concentrator. The number of patients treated by portable oxygen concentrator increased by 509% over the last 5 years. In 2019, 96,126 patients received NIV (144/100,000) and 97% of these patients were treated by NIV for less than 12 h/day. A total of 9,158 patients were treated by MI-E in 2019 (13.6/100,000). Despite the global increase in the number of patients, health costs decreased from 9% to 8% of total medical device spending in 2019 due to adjustment of health policies, such as a reduction of reimbursement rates. CONCLUSION: Our results highlighted the high rate of HRE prescription, but with cost control as a result of adapted health policies.

Monitoring Long Term Noninvasive Ventilation: Benefits, Caveats and Perspectives.

Long term noninvasive ventilation (LTNIV) is a recognized treatment for chronic hypercapnic respiratory failure (CHRF). COPD, obesity-hypoventilation syndrome, neuromuscular disorders, various restrictive disorders, and patients with sleep-disordered breathing are the major groups concerned. The purpose of this narrative review is to summarize current knowledge in the field of monitoring during home ventilation. LTNIV improves symptoms related to CHRF, diurnal and nocturnal blood gases, survival, and health-related quality of life. Initially, patients with LTNIV were most often followed through elective short in-hospital stays to ensure patient comfort, correction of daytime blood gases and nocturnal oxygenation, and control of nocturnal respiratory events. Because of the widespread use of LTNIV, elective in-hospital monitoring has become logistically problematic, time consuming, and costly. LTNIV devices presently have a built-in software which records compliance, leaks, tidal volume, minute ventilation, cycles triggered and cycled by the patient and provides detailed pressure and flow curves. Although the engineering behind this information is remarkable, the quality and reliability of certain signals may vary. Interpretation of the curves provided requires a certain level of training. Coupling ventilator software with nocturnal pulse oximetry or transcutaneous capnography performed at the patient's home can however provide important information and allow adjustments of ventilator settings thus potentially avoiding hospital admissions. Strategies have been described to combine different tools for optimal detection of an inefficient ventilation. Recent devices also allow adapting certain parameters at a distance (pressure support, expiratory positive airway pressure, back-up respiratory rate), thus allowing progressive changes in these settings for increased patient comfort and tolerance, and reducing the requirement for in-hospital titration. Because we live in a connected world, analyzing large groups of patients through treatment of "big data" will probably improve our knowledge of clinical pathways of our patients, and factors associated with treatment success or failure, adherence and efficacy. This approach provides a useful add-on to randomized controlled studies and allows generating hypotheses for better management of HMV.

Documento internacional de consenso sobre apnea obstructiva del sueño / International Consensus Document on Obstructive Sleep Apnea

El objetivo principal de este documento internacional de consenso sobre apnea obstructiva del sueño es proporcionar unas directrices que permitan a los profesionales sanitarios tomar las mejores decisiones en la asistencia de los pacientes adultos con esta enfermedad según un resumen crítico de la literatura más actualizada. El grupo de trabajo de expertos se ha constituido principalmente por 17 sociedades científicas y 56 especialistas con amplia representación geográfica (con la participación de 4 sociedades internacionales), además de un metodólogo experto y un documentalista del Centro Cochrane Iberoamericano. El documento consta de un manuscrito principal, con las novedades más relevantes, y una serie de manuscritos online que recogen las búsquedas bibliográficas sistemáticas de cada uno de los apartados del documento internacional de consenso. Este documento no cubre la edad pediátrica ni el manejo del paciente en ventilación mecánica crónica no invasiva (que se publicarán en sendos documentos de consenso aparte). Palabras clave: Apnea obstructiva del sueño Diagnóstico Tratamiento

The main aim of this international consensus document on obstructive sleep apnea is to provide guidelines based on a critical analysis of the latest literature to help health professionals make the best decisions in the care of adult patients with this disease. The expert working group was formed primarily of 17 scientific societies and 56 specialists from a wide geographical area (including the participation of 4 international societies), an expert in methodology, and a documentalist from the Iberoamerican Cochrane Center. The document consists of a main section containing the most significant innovations and a series of online manuscripts that report the systematic literature searches performed for each section of the international consensus document. This document does not discuss pediatric patients or the management of patients receiving chronic non-invasive mechanical ventilation (these topics will be addressed in separate consensus documents). Keywords: Obstructive sleep apnea Diagnosis Treatment

International Consensus Document on Obstructive Sleep Apnea. / Documento internacional de consenso sobre apnea obstructiva del sueño.

The main aim of this international consensus document on obstructive sleep apnea is to provide guidelines based on a critical analysis of the latest literature to help health professionals make the best decisions in the care of adult patients with this disease. The expert working group was formed primarily of 17 scientific societies and 56 specialists from a wide geographical area (including the participation of 4 international societies), an expert in methodology, and a documentalist from the Iberoamerican Cochrane Center. The document consists of a main section containing the most significant innovations and a series of online manuscripts that report the systematic literature searches performed for each section of the international consensus document. This document does not discuss pediatric patients or the management of patients receiving chronic non-invasive mechanical ventilation (these topics will be addressed in separate consensus documents).

Results of the home mechanical ventilation national program among adults in Chile between 2008 and 2017.

BACKGROUND: Home mechanical ventilation (HMV) is a viable and effective strategy for patients with chronic respiratory failure (CRF). The Chilean Ministry of Health started a program for adults in 2008. METHODS: This study examined the following data from a prospective cohort of patients with CRF admitted to the national HMV program: characteristics, mode of admission, quality of life, time in the program and survival. RESULTS: A total of 1105 patients were included. The median age was 59 years (44-58). Women accounted for 58.1% of the sample. The average body mass index (BMI) was 34.9 (26-46) kg/m2. A total of 76.2% of patients started HMV in the stable chronic mode, while 23.8% initiated HMV in the acute mode. A total of 99 patients were transferred from the children's program. There were 1047 patients on non-invasive ventilation and 58 patients on invasive ventilation. The median baseline PaCO2 level was 58.2 (52-65) mmHg. The device usage time was 7.3 h/d (5.8-8.8), and the time in HMV was 21.6 (12.2-49.5) months. The diagnoses were COPD (35%), obesity hypoventilation syndrome (OHS; 23.9%), neuromuscular disease (NMD; 16.3%), non-cystic fibrosis bronchiectasis or tuberculosis (non-CF BC or TBC; 8.3%), scoliosis (5.9%) and amyotrophic lateral sclerosis (ALS; 5.24%). The baseline score on the Severe Respiratory Insufficiency questionnaire (SRI) was 47 (± 17.9) points and significantly improved over time. The lowest 1- and 3-year survival rates were observed in the ALS group, and the lowest 9-year survival rate was observed in the non-CF BC or TB and COPD groups. The best survival rates at 9 years were OHS, scoliosis and NMD. In 2017, there were 701 patients in the children's program and 722 in the adult´s program, with a prevalence of 10.4 per 100,000 inhabitants. CONCLUSION: The most common diagnoses were COPD and OHS. The best survival was observed in patients with OHS, scoliosis and NMD. The SRI score improved significantly in the follow-up of patients with HMV. The prevalence of HMV was 10.4 per 100,000 inhabitants. Trial registration This study was approved by and registered at the ethics committee of North Metropolitan Health Service of Santiago, Chile (N° 018/2021).

Recommended Approaches to Minimize Aerosol Dispersion of SARS-CoV-2 During Noninvasive Ventilatory Support Can Cause Ventilator Performance Deterioration: A Benchmark Comparative Study.

BACKGROUND: SARS-CoV-2 aerosolization during noninvasive positive-pressure ventilation may endanger health care professionals. Various circuit setups have been described to reduce virus aerosolization. However, these setups may alter ventilator performance. RESEARCH QUESTION: What are the consequences of the various suggested circuit setups on ventilator efficacy during CPAP and noninvasive ventilation (NIV)? STUDY DESIGN AND METHODS: Eight circuit setups were evaluated on a bench test model that consisted of a three-dimensional printed head and an artificial lung. Setups included a dual-limb circuit with an oronasal mask, a dual-limb circuit with a helmet interface, a single-limb circuit with a passive exhalation valve, three single-limb circuits with custom-made additional leaks, and two single-limb circuits with active exhalation valves. All setups were evaluated during NIV and CPAP. The following variables were recorded: the inspiratory flow preceding triggering of the ventilator, the inspiratory effort required to trigger the ventilator, the triggering delay, the maximal inspiratory pressure delivered by the ventilator, the tidal volume generated to the artificial lung, the total work of breathing, and the pressure-time product needed to trigger the ventilator. RESULTS: With NIV, the type of circuit setup had a significant impact on inspiratory flow preceding triggering of the ventilator (P < .0001), the inspiratory effort required to trigger the ventilator (P < .0001), the triggering delay (P < .0001), the maximal inspiratory pressure (P < .0001), the tidal volume (P = .0008), the work of breathing (P < .0001), and the pressure-time product needed to trigger the ventilator (P < .0001). Similar differences and consequences were seen with CPAP as well as with the addition of bacterial filters. Best performance was achieved with a dual-limb circuit with an oronasal mask. Worst performance was achieved with a dual-limb circuit with a helmet interface. INTERPRETATION: Ventilator performance is significantly impacted by the circuit setup. A dual-limb circuit with oronasal mask should be used preferentially.