Predictors of failure of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multi-center study

High-flow nasal cannula therapy for acute respiratory failure in patients with interstitial pneumonia: a retrospective observational study

High-flow nasal cannula (HFNC) oxygen is a therapy that has demonstrated survival benefits in acute respiratory failure (ARF). However, the role of HFNC in ARF due to interstitial pneumonia (IP) is unknown. The aim of this study was to compare the effects of HFNC therapy and non-invasive positive pressure ventilation (NPPV) in ARF due to IP. This retrospective observational study included 32 patients with ARF due to IP who were treated with HFNC (n = 13) or NPPV (n = 19). The clinical characteristics, intubation rate and 30-day mortality were analyzed and compared between the HFNC group and the NPPV group. Predictors of 30-day mortality were evaluated using a logistic regression model. HFNC group showed higher mean arterial blood pressure (median 92 mmHg; HFNC group vs 74 mmHg; NPPV group) and lower APACHEII score (median 22; HFNC group vs 27; NPPV group) than NPPV group. There was no significant difference in the intubation rate at day 30 between the HFNC group and the NPPV group (8% vs 37%: p = 0.069); the mortality rate at 30 days was 23% and 63%, respectively. HFNC therapy was a significant determinant of 30-day mortality in univariate analysis, and was confirmed to be an independent significant determinant of 30-day mortality in multivariate analysis (odds ratio, 0.148; 95% confidence interval, 0.025–0.880; p = 0.036). Our findings suggest that HFNC therapy can be a possible option for respiratory management in ARF due to IP. The results observed here warrant further investigation of HFNC therapy in randomized control trials.

Noninvasive ventilation and high-flow oxygen therapy for severe community-acquired pneumonia

PURPOSE OF REVIEW

We review the evidence on the use of noninvasive respiratory supports (noninvasive ventilation and high-flow nasal cannula oxygen therapy) in patients with acute respiratory failure because of severe community-acquired pneumonia.

RECENT FINDINGS

Noninvasive ventilation is strongly advised for the treatment of hypercapnic respiratory failure and recent evidence justifies its use in patients with hypoxemic respiratory failure when delivered by helmet. Indeed, such interface allows alveolar recruitment by providing high level of positive end-expiratory pressure, which improves hypoxemia. On the other hand, high-flow nasal cannula oxygen therapy is effective in patients with hypoxemic respiratory failure and some articles support its use in patients with hypercapnia. However, early identification of noninvasive respiratory supports treatment failure is crucial to prevent delayed orotracheal intubation and protective invasive mechanical ventilation.

SUMMARY

Noninvasive ventilation is the first-line therapy in patients with acute hypercapnic respiratory failure because of pneumonia. Although an increasing amount of evidence investigated the application of noninvasive respiratory support to hypoxemic respiratory failure, the optimal ventilatory strategy in this setting is uncertain. Noninvasive mechanical ventilation delivered by helmet and high-flow nasal cannula oxygen therapy appear as promising tools but their role needs to be confirmed by future research.

Blunt Chest Trauma and Regional Anesthesia for Analgesia of Multitrauma Patients in French Intensive Care Units: A National Survey

BACKGROUND

Chest injuries are associated with mortality among patients admitted to the intensive care unit (ICU) and require multimodal pain management strategies, including regional anesthesia (RA). We conducted a survey to determine the current practices of physicians working in ICUs regarding RA for the management of chest trauma in patients with multiple traumas.

METHODS

An online questionnaire was sent to medical doctors (n = 1230) working in French ICUs, using the Société Française d'Anesthésie Réanimation (SFAR) mailing list of its members. The questionnaire addressed 3 categories: general characteristics, practical aspects of RA, and indications and contraindications.

RESULTS

Among the 333 respondents (response rate = 27%), 78% and 40% of 156 respondents declared that they would consider using thoracic epidural analgesia (TEA) and thoracic paravertebral blockade (TPB), respectively. The main benefits declared for performing RA were the ability to have effective analgesia, a more effective cough, and early rehabilitation. For 70% of the respondents, trauma patients with a theoretical indication of RA did not receive TEA or TPB for the following reasons: the ICU had no experience of RA (62%), no anesthesiologist-intensivist working in the ICU (46%), contraindications (27%), ignorance of the SFAR guidelines (19%), and no RA protocol available (13%). In this survey, 95% of the respondents thought the prognosis of trauma patients could be influenced by the use of RA.

CONCLUSIONS

While TEA and TPB are underused because of several limitations related to the patterns of injuries in multitrauma patients, lack of both experience and confidence in combination with the absence of available protocols appear to be the major restraining factors, even if physicians are aware that patients' outcomes could be improved by RA. These results suggest the need to strengthen initial training and provide continuing education about RA in the ICU.

A simple nomogram for predicting failure of non-invasive respiratory strategies in adults with COVID-19: a retrospective multicentre study

Background

Non-invasive respiratory strategies (NIRS) including high-flow nasal cannula (HFNC) and non-invasive ventilation (NIV) have become widely used in patients with COVID-19 who develop acute respiratory failure. However, use of these therapies, if ineffective, might delay initiation of invasive mechanical ventilation (IMV) in some patients. We aimed to determine early predictors of NIRS failure and develop a simple nomogram and online calculator that can identify patients at risk of NIRS failure.

Methods

We did a retrospective, multicentre observational study in 23 hospitals designated for patients with COVID-19 in China. Adult patients (≥18 years) with severe acute respiratory syndrome coronavirus 2 infection and acute respiratory failure receiving NIRS were enrolled. A training cohort of 652 patients (21 hospitals) was used to identify early predictors of NIRS failure, defined as subsequent need for IMV or death within 28 days after intensive care unit admission. A nomogram was developed by multivariable logistic regression and concordance statistics (C-statistics) computed. C-statistics were validated internally by cross-validation in the training cohort, and externally in a validation cohort of 107 patients (two hospitals).

Findings

Patients were enrolled between Jan 1 and Feb 29, 2020. NIV failed in 211 (74%) of 286 patients and HFNC in 204 (56%) of 366 patients in the training cohort. NIV failed in 48 (81%) of 59 patients and HFNC in 26 (54%) of 48 patients in the external validation cohort. Age, number of comorbidities, respiratory rate–oxygenation index (ratio of pulse oximetry oxygen saturation/fraction of inspired oxygen to respiratory rate), Glasgow coma scale score, and use of vasopressors on the first day of NIRS in the training cohort were independent risk factors for NIRS failure. Based on the training dataset, the nomogram had a C-statistic of 0·80 (95% CI 0·74–0·85) for predicting NIV failure, and a C-statistic of 0·85 (0·82–0·89) for predicting HFNC failure. C-statistic values were stable in both internal validation (NIV group mean 0·79 [SD 0·10], HFNC group mean 0·85 [0·07]) and external validation (NIV group value 0·88 [95% CI 0·72–0·96], HFNC group value 0·86 [0·72–0·93]).

Interpretation

We have developed a nomogram and online calculator that can be used to identify patients with COVID-19 who are at risk of NIRS failure. These patients might benefit from early triage and more intensive monitoring.

Funding

Ministry of Science and Technology of the People's Republic of China, Key Research and Development Plan of Jiangsu Province, Chinese Academy of Medical Sciences.

A scoring system derived from electronic health records to identify patients at high risk for noninvasive ventilation failure

OBJECTIVE

To develop and validate a clinical risk prediction score for noninvasive ventilation (NIV) failure defined as intubation after a trial of NIV in non-surgical patients.

DESIGN

Retrospective cohort study of a multihospital electronic health record database.

PATIENTS

Non-surgical adult patients receiving NIV as the first method of ventilation within two days of hospitalization.

MEASUREMENT

Primary outcome was intubation after a trial of NIV. We used a non-random split of the cohort based on year of admission for model development and validation. We included subjects admitted in years 2010-2014 to develop a risk prediction model and built a parsimonious risk scoring model using multivariable logistic regression. We validated the model in the cohort of subjects hospitalized in 2015 and 2016.

MAIN RESULTS

Of all the 47,749 patients started on NIV, 11.7% were intubated. Compared with NIV success, those who were intubated had worse mortality (25.2% vs. 8.9%). Strongest independent predictors for intubation were organ failure, principal diagnosis group (substance abuse/psychosis, neurological conditions, pneumonia, and sepsis), use of invasive ventilation in the prior year, low body mass index, and tachypnea. The c-statistic was 0.81, 0.80 and 0.81 respectively, in the derivation, validation and full cohorts. We constructed three risk categories of the scoring system built on the full cohort; the median and interquartile range of risk of intubation was: 2.3% [1.9%-2.8%] for low risk group; 9.3% [6.3%-13.5%] for intermediate risk category; and 35.7% [31.0%-45.8%] for high risk category.

CONCLUSIONS

In patients started on NIV, we found that in addition to factors known to be associated with intubation, neurological, substance abuse, or psychiatric diagnoses were highly predictive for intubation. The prognostic score that we have developed may provide quantitative guidance for decision-making in patients who are started on NIV.

Ventilation of coronavirus disease 2019 patients

PURPOSE OF REVIEW

To summarize the current knowledge of pathophysiology and ventilatory management of acute respiratory failure in COVID-19.

RECENT FINDINGS

Early reports suggested that COVID-19 is an 'atypical ARDS' with profound hypoxemia with normal respiratory system compliance (Crs). Contrarily, several more populated analyses showed that COVID-19 ARDS has pathophysiological features similar to non-COVID-19 ARDS, with reduced Crs, and high heterogeneity of respiratory mechanics, hypoxemia severity, and lung recruitability. There is no evidence supporting COVID-19-specific ventilatory settings, and the vast amount of available literature suggests that evidence-based, lung-protective ventilation (i.e. tidal volume ≤6 ml/kg, plateau pressure ≤30 cmH2O) should be enforced in all mechanically ventilated patients with COVID-19 ARDS. Mild and moderate COVID-19 can be managed outside of ICUs by noninvasive ventilation in dedicated respiratory units, and no evidence support an early vs. late intubation strategy. Despite widely employed, there is no evidence supporting the efficacy of rescue therapies, such as pronation, inhaled vasodilators, or extracorporeal membrane oxygenation.

SUMMARY

Given the lack of evidence-based specific ventilatory strategies and a large amount of literature showing pathophysiological features similar to non-COVID-19 ARDS, evidence-based lung-protective ventilatory strategies should be pursued in all patients with COVID-19 ARDS.

Noninvasive ventilation in critically ill very old patients with pneumonia: A multicenter retrospective cohort study

Background

Very old patients (≥ 80 years-old, VOP) are increasingly admitted to intensive care units (ICUs). Community-acquired pneumonia (CAP) is a common reason for admission and the best strategy of support for respiratory failure in this scenario is not fully known. We evaluated whether noninvasive ventilation (NIV) would be beneficial compared to invasive mechanical ventilation (IMV) regarding hospital mortality.

Methods

Multicenter cohort study of VOPs admitted with CAP in need of IMV or NIV to 11 Brazilian ICUs from 2009 through 2012. We used logistic regression models to evaluate the association between the initial ventilatory strategy (NIV vs. IMV) and hospital mortality adjusting for confounding factors. We evaluated effect modification with interaction terms in pre-specified sub-groups.

Results

Of 369 VOPs admitted for CAP with respiratory failure, 232 (63%) received NIV and 137 (37%) received IMV as initial ventilatory strategy. IMV patients were sicker at baseline (median SOFA 8 vs. 4). Hospital mortality was 114/232 (49%) for NIV and 90/137 (66%) for IMV. For the comparison NIV vs. IMV (reference), the crude odds ratio (OR) was 0.50 (95% CI, 0.33–0.78, p = 0.002). This association was largely confounded by antecedent characteristics and non-respiratory SOFA (_adjOR = 0.70, 95% CI, 0.41–1.20, p = 0.196). The fully adjusted model, additionally including P_ao₂/F_io₂ ratio, pH and P_aco₂, yielded an _adjOR of 0.81 (95% CI, 0.46–1.41, p = 0.452). There was no strong evidence of effect modification among relevant subgroups, such as P_ao₂/F_io₂ ratio ≤ 150 (p = 0.30), acute respiratory acidosis (p = 0.42) and non-respiratory SOFA ≥ 4 (p = 0.53).

Conclusions

NIV was not associated with lower hospital mortality when compared to IMV in critically ill VOP admitted with CAP, but there was no strong signal of harm from its use. The main confounders of this association were both the severity of respiratory dysfunction and of extra-respiratory organ failures.

Safety and Efficacy of Dexmedetomidine in Acutely Ill Adults Requiring Noninvasive Ventilation: A Systematic Review and Meta-analysis of Randomized Trials

BACKGROUND

Although clinical studies have evaluated dexmedetomidine as a strategy to improve noninvasive ventilation (NIV) comfort and tolerance in patients with acute respiratory failure (ARF), their results have not been summarized.

RESEARCH QUESTION

Does dexmedetomidine, when compared with another sedative or placebo, reduce the risk of delirium, mortality, need for intubation and mechanical ventilation, or ICU length of stay (LOS) in adults with ARF initiated on NIV in the ICU?

STUDY DESIGN AND METHODS

We electronically searched MEDLINE, EMBASE, and the Cochrane Library from inception through July 31, 2020, for randomized clinical trials (RCTs). We calculated pooled relative risks (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes with the corresponding 95% CIs using a random-effect model.

RESULTS

Twelve RCTs were included in our final analysis (n = 738 patients). The use of dexmedetomidine, compared with other sedation strategies or placebo, reduced the risk of intubation (RR, 0.54; 95% CI, 0.41-0.71; moderate certainty), delirium (RR, 0.34; 95% CI, 0.22-0.54; moderate certainty), and ICU LOS (MD, -2.40 days; 95% CI, -3.51 to -1.29 days; low certainty). Use of dexmedetomidine was associated with an increased risk of bradycardia (RR, 2.80; 95% CI, 1.92-4.07; moderate certainty) and hypotension (RR, 1.98; 95% CI, 1.32-2.98; moderate certainty).

INTERPRETATION

Compared with any sedation strategy or placebo, dexmedetomidine reduced the risk of delirium and the need for mechanical ventilation while increasing the risk of bradycardia and hypotension. The results are limited by imprecision, and further large RCTs are needed.

TRIAL REGISTRY

PROSPERO; No.: 175086; URL: www.crd.york.ac.uk/prospero/.

Multidimensional prognostic index (MPI) predicts non-invasive ventilation failure in older adults with acute respiratory failure

BACKGROUND

Acute respiratory failure (ARF) is a very common complication among hospitalized older adults. Non-invasive ventilation (NIV) may avoid admission to intensive care units, intubation and their related complication, but still lacks specific indications in older adults. Multidimensional Prognostic Index (MPI) based on comprehensive geriatric assessment (CGA) could have a role in defining the short-term prognosis and the best candidates for NIV among older adults with ARF.

METHODS

This is a retrospective observational study which enrolled patients older than 70 years, consecutively admitted to an acute geriatric unit with ARF. A standardized CGA was used to calculate the MPI at admission. Multivariate Cox regression models were used to test if MPI score could predict in-hospital mortality and NIV failure. Receiver operator curve (ROC) analysis was used to identify the discriminatory power of MPI for NIV failure.

RESULTS

We enrolled 231 patients (88.2 ± 5.9 years, 47% females). Mean MPI at admission was 0.76±0.16. In-hospital mortality rate was 33.8%, with similar incidence in patients treated with and without NIV. Among NIV users (26.4%), NIV failure occurred in 39.3%. Higher MPI scores at admission significantly predicted in-hospital mortality (β=4.46, p<0.0001) among patients with ARF and NIV failure (β=7.82, p = 0.001) among NIV users. MPI showed good discriminatory power for NIV failure (area under the curve: 0.72, 95% CI: 0.58-0.85, p<0.001) with optimal cut-off at MPI value of 0.84.

CONCLUSIONS

MPI at admission might be a useful tool to early detect patients more at risk of in-hospital death and NIV failure among older adults with ARF.

Multidisciplinary Approach to the Diagnosis and In-Hospital Management of COVID-19 Infection: A Narrative Review

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2 or COVID-19 disease) was declared a pandemic on 11th March 2020 by the World Health Organization. This unprecedented circumstance has challenged hospitals' response capacity, requiring significant structural and organizational changes to cope with the surge in healthcare demand and to minimize in-hospital risk of transmission. As our knowledge advances, we now understand that COVID-19 is a multi-systemic disease rather than a mere respiratory tract infection, therefore requiring holistic care and expertise from various medical specialties. In fact, the clinical spectrum of presentation ranges from respiratory complaints to gastrointestinal, cardiac or neurological symptoms. In addition, COVID-19 pandemic has created a global burden of mental illness that affects the general population as well as healthcare practitioners. The aim of this manuscript is to provide a comprehensive and multidisciplinary insight into the complexity of this disease, reviewing current scientific evidence on COVID-19 management and treatment across several medical specialties involved in the in-hospital care of these patients.

Noninvasive ventilation with a helmet in patients with acute respiratory failure caused by chest trauma: a randomized controlled trial

Noninvasive ventilation (NIV) is beneficial in acute respiratory failure (ARF) caused by chest trauma; however, NIV-related complications affect the efficacy. We evaluated whether NIV with helmet decreases the incidence of complications and improves its effects in a single center. Patients with ARF after chest trauma were randomized to receive NIV with helmet or face mask. The primary outcome was the rate of NIV-related complications. Secondary outcomes were PaO₂/FiO₂, patient’s tolerance, intubation rate, length of intensive care unit (ICU) stay, and ICU mortality. The trial was terminated early after an interim analysis with 59 patients. The incidence of complications was lower in the helmet group [10% (3/29) vs 43% (13/30), P = 0.004], and PaO₂/FiO₂s were higher at 1 h and at the end of NIV (253.14 ± 64.74 mmHg vs 216.06 ± 43.86 mmHg, 277.07 ± 84.89 mmHg vs 225.81 ± 63.64 mmHg, P = 0.013 and 0.012) compared with them in face mask group. More patients reported excellent tolerance of the helmet vs face mask after 4 h of NIV [83% (24/29) vs 47% (14/30), P = 0.004] and at the end of NIV [69% (20/29) vs 30% (9/30), P = 0.03]. Differences in intubation rate, ICU stay, and mortality were non-significant (P = 0.612, 0.100, 1.000, respectively). NIV with helmet decreased NIV-related complications, increased PaO₂/FiO₂, and improved tolerance compared with NIV with face mask in patients with chest trauma.

Trial registration: Registered in the Chinese Clinical Trial Registry (ChiCTR1900025915), a WHO International Clinical Trials Registry Platform (http://www.chictr.org.cn/searchprojen.aspx).

Diagnosis and Management of Acute Respiratory Distress Syndrome in a Time of COVID-19

Acute respiratory distress syndrome (ARDS) remains a serious illness with significant morbidity and mortality, characterized by hypoxemic respiratory failure most commonly due to pneumonia, sepsis, and aspiration. Early and accurate diagnosis of ARDS depends upon clinical suspicion and chest imaging. Coronavirus disease 2019 (COVID-19) is an important novel cause of ARDS with a distinct time course, imaging and laboratory features from the time of SARS-CoV-2 infection to hypoxemic respiratory failure, which may allow diagnosis and management prior to or at earlier stages of ARDS. Treatment of ARDS remains largely supportive, and consists of incremental respiratory support (high flow nasal oxygen, non-invasive respiratory support, and invasive mechanical ventilation), and avoidance of iatrogenic complications, all of which improve clinical outcomes. COVID-19-associated ARDS is largely similar to other causes of ARDS with respect to pathology and respiratory physiology, and as such, COVID-19 patients with hypoxemic respiratory failure should typically be managed as other patients with ARDS. Non-invasive respiratory support may be beneficial in avoiding intubation in COVID-19 respiratory failure including mild ARDS, especially under conditions of resource constraints or to avoid overwhelming critical care resources. Compared to other causes of ARDS, medical therapies may improve outcomes in COVID-19-associated ARDS, such as dexamethasone and remdesivir. Future improved clinical outcomes in ARDS of all causes depends upon individual patient physiological and biological endotyping in order to improve accuracy and timeliness of diagnosis as well as optimal targeting of future therapies in the right patient at the right time in their disease.

Early Inspiratory Effort Assessment by Esophageal Manometry Predicts Noninvasive Ventilation Outcome in De Novo Respiratory Failure. A Pilot Study

Rationale: The role of inspiratory effort still has to be determined as a potential predictor of noninvasive mechanical ventilation (NIV) failure in acute hypoxic de novo respiratory failure.Objectives: To explore the hypothesis that inspiratory effort might be a major determinant of NIV failure in these patients.Methods: Thirty consecutive patients with acute hypoxic de novo respiratory failure admitted to a single center and candidates for a 24-hour NIV trial were enrolled. Clinical features, tidal change in esophageal pressure (ΔPes), tidal change in dynamic transpulmonary pressure (ΔPl), expiratory Vt, and respiratory rate were recorded on admission and 2-4 to 12-24 hours after NIV start and were tested for correlation with outcomes.Measurements and Main Results: ΔPes and ΔPes/ΔPl ratio were significantly lower 2 hours after NIV start in patients who successfully completed the NIV trial (n = 18) compared with those who needed endotracheal intubation (n = 12) (median [interquartile range], 11 [8-15] cm H₂O vs. 31.5 [30-36] cm H₂O; P < 0.0001), whereas other variables differed later. ΔPes was not related to other predictors of NIV failure at baseline. NIV-induced reduction in ΔPes of 10 cm H₂O or more after 2 hours of treatment was strongly associated with avoidance of intubation and represented the most accurate predictor of treatment success (odds ratio, 15; 95% confidence interval, 2.8-110; P = 0.001 and area under the curve, 0.97; 95% confidence interval, 0.91-1; P < 0.0001).Conclusions: The magnitude of inspiratory effort relief as assessed by ΔPes variation within the first 2 hours of NIV was an early and accurate predictor of NIV outcome at 24 hours.Clinical trial registered with www.clinicaltrials.gov (NCT03826797).

Continuous Positive Airway Pressure (CPAP) face-mask ventilation is an easy and cheap option to manage a massive influx of patients presenting acute respiratory failure during the SARS-CoV-2 outbreak: A retrospective cohort study

INTRODUCTION

Because of the COVID-19 pandemic, intensive care units (ICU) can be overwhelmed by the number of hypoxemic patients.

MATERIAL AND METHODS

This single centre retrospective observational cohort study took place in a French hospital where the number of patients exceeded the ICU capacity despite an increase from 18 to 32 beds. Because of this, 59 (37%) of the 159 patients requiring ICU care were referred to other hospitals. From 27th March to 23rd April, consecutive patients who had respiratory failure or were unable to maintain an SpO2 > 90%, despite receiving 10-15 l/min of oxygen with a non-rebreather mask, were treated by continuous positive airway pressure (CPAP) unless the ICU physician judged that immediate intubation was indicated. We describe the characteristics, clinical course, and outcomes of these patients. The main outcome under study was CPAP discontinuation.

RESULTS

CPAP was initiated in 49 patients and performed out of ICU in 41 (84%). Median age was 65 years (IQR = 54-71) and 36 (73%) were men. Median respiratory rate before CPAP was 36 (30-40) and median SpO2 was 92% (90-95) under 10 to 15 L/min oxygen flow. Median duration of CPAP was 3 days (IQR = 1-5). Reasons for discontinuation of CPAP were: intubation in 25 (51%), improvement in 16 (33%), poor tolerance in 6 (12%) and death in 2 (4%) patients. A decision not to intubate had been taken for 8 patients, including the 2 who died while on CPAP. Two patients underwent less than one hour CPAP for poor tolerance. In the end, 15 (38%) out of 39 evaluable patients recovered with only CPAP whereas 24 (62%) were intubated.

CONCLUSIONS

CPAP is feasible in a non-ICU environment in the context of massive influx of patients. In our cohort up to 1/3 of the patients presenting with acute respiratory failure recovered without intubation.

Non-Invasive Ventilation in a Non-Standard Setting – Is it Safe to Ventilate Outside the ICU?

Non-invasive ventilation (NIV) is considered a fundamental method in treating patients with various disorders, requiring respiratory support. Often the lack of beds in the intensive care unit (ICU) and the concomitant medical conditions, which refer patients as unsuitable for aggressive treatment in the ICU, highlight the need of NIV application in general non-monitored wards and unusual settings – most commonly emergency departments, high-dependency units, pulmonary wards, and even ambulances. Recent studies suggest faster improvement of all physiological variables, reduced intubation rates, postoperative pulmonary complications and hospital mortality with better outcome and quality of life by early well-monitored ward-based NIV compared to standard medical therapy in patients with exacerbation of a chronic obstructive pulmonary disease, after a surgical procedure or acute hypoxemic respiratory failure in hematologic malignancies. NIV is a ceiling of treatment and a comfort measure in many patients with do-not-intubate orders due to terminal illnesses. NIV is beneficial only by proper administration with appropriate monitoring and screening for early NIV failure. Successful NIV application in a ward requires a well-equipped area and adequately trained multidisciplinary team. It could be initiated not only by attending physicians, respiratory technicians, and nurses but also by medical emergency teams. Ward-based NIV is supposed to be more cost-effective than NIV in the ICU, but further investigation is required to establish the safety and efficacy in hospital wards with a low nurse to patient ratio.

Risk factors for non-invasive ventilation failure in influenza infection with acute respiratory failure in emergency department

OBJECTIVE

Non-invasive ventilation (NIV) has been widely used in hypoxemic acute respiratory failure (ARF) due to influenza pneumonia in the emergency department (ED). However, NIV used in influenza-associated acute respiratory failure had a variable rate of failure. Previous studies have reported that prolonged use of NIV was associated with increased mortality. Our study aimed to identify risk factors for NIV failure in influenza infection with acute respiratory failure in ED.

METHOD

We performed a retrospective cohort observational study. Enrolled patients were older than 18 years who used NIV due to influenza infection with ARF between 1 January 2017 to 31 December 2018 in Ramathibodi Emergency Department. Patients characteristics, comorbidity, clinical, laboratory outcome, chest imaging, initial NIV setting, and parameters were collected in ED setting. Sequential organ failure assessment (SOFA) score and PaO2/FiO2 (PF) ratio were calculated from the first arterial blood gas in ED. We followed the outcome success or failure of the NIV used.

RESULTS

A total of 162 patients were enrolled and 72 (44%) suffered NIV failure in influenza infection with ARF. We used univariate and multivariate logistic analyses to assess risk factors for NIV failure. The ability of risk factor to predict NIV failure was analyzed using the area under the receiver operating characteristic (AUROC). Risk factors of NIV failure included SOFA score (P = 0.001), PF ratio (P = 0.001) and quadrant infiltrations in chest x-rays (CXR) (P = 0.001). SOFA score, PF ratio, and number quadrant infiltrations in chest radiography have good ability to predict NIV failure, AUROC 0.894 (95%CI 0.839-0.948), 0.828 (95%CI 0.764-0.892), and 0.792 (95%CI 0.721-0.863), respectively and no significant difference in the ability to predict NIV failure among three parameters. The use of PF ratio plus number quadrant infiltrations in chest radiography demonstrated a higher predictive ability for NIV failure in influenza infection with ARF.

CONCLUSIONS

SOFA score, PF ratio, and quadrant infiltrations in chest radiography were good predictors of NIV failure in influenza infection with ARF.

Clinical Challenges in an Outbreak of COVID-19 in Wuhan, China: Concerns from Frontiers

PURPOSE OF REVIEW

In December 2019, outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected pneumonia patients were discovered in Wuhan City, Hubei Province, China. With the spread of the epidemic, new cases have been found in other regions of China and abroad. This review summarizes the current coronavirus disease 2019 (COVID-19) transmission pathways, high-risk factors, diagnostic points, pathogenesis, and therapeutic drugs to provide the prevention and treatment theories for COVID-19.

RECENT FINDINGS

COVID-19 is highly contagious and is transmitted mainly through the respiratory tract. Most patients with SARS-CoV-2 infection have milder symptoms. Some patients will have mild disease in the early stage, suddenly exacerbate later, and eventually die of multiple organ failure caused by cytokine storm. The basis for clinical diagnosis of COVID-19 is not just the detection of viral nucleic acids as the gold standard. The diagnostic accuracy improves when viral nucleic acid test is combined with clinical symptoms, CT results, and biochemical tests. For the treatment of COVID-19, the specific antiviral agents have not been developed, except for symptomatic supportive treatments.

SUMMARY

The methods for detecting SARS-CoV-2 infection have become increasingly mature, but specific antiviral drugs for the treatment of COVID-19 have not yet been developed. Treatment must pay attention to the cytokine storm that leads to the seriousness of COVID-19.

Current Controversies in Caring for the Critically Ill Pulmonary Embolism Patient

Emergency physicians must be prepared to rapidly diagnose and resuscitate patients with pulmonary embolism (PE). Certain aspects of PE resuscitation run counter to typical approaches. A specific understanding of the pathophysiology of PE is required to avoid cardiovascular collapse potentially associated with excessive intravenous fluids and positive pressure ventilation. Once PE is diagnosed, rapid risk stratification should be performed and treatment guided by patient risk class. Although anticoagulation remains the mainstay of PE treatment, emergency physicians also must understand the indications and contraindications for thrombolysis and should be aware of new therapies and models of care that may improve outcomes.

Validity of a clinical scale in predicting the failure of non-invasive ventilation in hypoxemic patients

INTRODUCTION

The HACOR scale is a clinical score that can predict early failure of NIV in hypoxemic acute respiratory failure (ARF) The aim of this study is to analyze the validity of the HACOR scale.

METHODS

A retrospective study of a cohort of over 2749 episodes on 2711 consecutive patients requiring NIV for hypoxemic ARF in a polyvalent intensive care unit. The scale was measured before starting NIV and at 1, 6, 12, 24 and 48 h after the initiation of NIV.

RESULTS

NIV failure occurred in 963 patients (35%). The value of the HACOR scale before NIV did not differ between success and failure. However, at 1, 6, 12, 24 and 48 h of NIV, the scale values clearly differed between the two groups. The HACOR scale at NIV initiation accurately predicts NIV failure in the first hour, with an optimal cut-off value of 8 points. The AUC for predicting NIV failure with HACOR at 1 h is greater than 0.9 in patients with pneumonia and adult respiratory distress syndrome (ARDS).

CONCLUSIONS

The HACOR scale measured at 1 h after NIV initiation accurately predicts NIV failure, especially in pneumonia and ARDS.

Predictive Factors for Failure of Noninvasive Ventilation in Adult Intensive Care Unit: A Retrospective Clinical Study

Background

Noninvasive ventilation (NIV) has been reported to be beneficial for patients with acute respiratory failure in intensive care unit (ICU); however, factors that influence the clinical outcome of NIV were unclarified. We aim to determine the factors that predict the failure of NIV in critically ill patients with acute respiratory failure (ARF). Setting. Adult mixed ICU in a medical university affiliated hospital. Patients and Methods. A retrospective clinical study using data from critical adult patients with initial NIV admitted to ICU in the period August 2016 to November 2017. Failure of NIV was regarded as patients needing invasive ventilation. Logistic regression was employed to determine the risk factor(s) for NIV, and a predictive model for NIV outcome was set up using risk factors.

Results

Of 101 included patients, 50 were unsuccessful. Although more than 20 variables were associated with NIV failure, multivariate logistic regression demonstrated that only ideal body weight (IBW) (OR 1.110 (95%1.027-1.201), P=0.009), the maximal heart rate during NIV period (HR-MAX) (OR 1.024 (1.004-1.046), P=0.021), the minimal respiratory rate during NIV period (RR-MIN) (OR 1.198(1.051-1.365), P=0.007), and the highest body temperature during NIV period (T-MAX) (OR 1.838(1.038-3.252), P=0.037) were independent risk factors for NIV failure. We set up a predictive model based on these independent risk factors, whose area under the receiver operating characteristic curve (AUROC) was 0.783 (95% CI: 0.676-0.899, P < 0.001), and the sensitivity and specificity of model were 68.75% and 71.43%, respectively, with the optimal cut-off value of 0.4863.

Conclusion

IBW, HR-MAX, RR-MIN, and T-MAX were associated with NIV failure in patients with ARF. A predictive model based on the risk factors could help to discriminate patients who are vulnerable to NIV failure.

Factors for Predicting Noninvasive Ventilation Failure in Elderly Patients with Respiratory Failure

Noninvasive ventilation (NIV) is useful when managing critically ill patients. However, it is not easy to apply to elderly patients, particularly those with pneumonia, due to the possibility of NIV failure and the increased mortality caused by delayed intubation. In this prospective observational study, we explored whether NIV was appropriate for elderly patients with pneumonia, defined factors that independently predicted NIV failure, and built an optimal model for prediction of such failure. We evaluated 78 patients with a median age of 77 years. A low PaCO2 level, a high heart rate, and the presence of pneumonia were statistically significant independent predictors of NIV failure. The predictive power for NIV failure of Model III (pneumonia, PaCO2 level, and heart rate) was better than that of Model I (pneumonia alone). Considering the improvement in parameters, patients with successful NIV exhibited significantly improved heart rates, arterial pH and PaCO2 levels, and patients with NIV failure exhibited a significantly improved PaCO2 level only. In conclusion, NIV is reasonable to apply to elderly patients with pneumonia, but should be done with caution. For the early identification of NIV failure, the heart rate and arterial blood gas parameters should be monitored within 2 h after NIV commencement.

Noninvasive ventilation failure in patients with hypoxemic respiratory failure: the role of sepsis and septic shock

BACKGROUND

Sepsis and septic shock are common in noninvasive ventilation (NIV) patients. However, studies on the association between sepsis and NIV failure are lacking.

METHODS

A prospective multi-center observational study was performed in 16 Chinese intensive care units (ICUs). Patients who used NIV due to hypoxemic respiratory failure were enrolled. Sepsis and septic shock were diagnosed according to the guideline of sepsis-3.

RESULTS

A total of 519 patients were enrolled. Sepsis developed in 365 patients (70%) and septic shock developed in 79 patients (15%). However, 75 patients (14%) had no sepsis. NIV failure was 23%, 38%, and 61% in patients, with no sepsis, sepsis, and septic shock, respectively. Multivariate analysis found that sepsis [odds ratio (OR) = 1.95, 95% confidence interval (CI): 1.06-3.61] and septic shock (OR = 2.47, 95% CI: 1.12-5.45) were independently associated with NIV failure. In sepsis and septic shock population, the NIV failure was 13%, 31%, 37%, 53%, and 67% in patients with sequential organ failure assessment (SOFA) scores of ⩽2, 3-4, 5-6, 7-8, and ⩾9, respectively. Patients with nonpulmonary induced sepsis had similar NIV failure rate compared with those with pulmonary induced sepsis, but had higher proportion of septic shock (37% versus 10%, p ⩽ 0.01) and lower ICU mortality (10% versus 22%, p ⩽ 0.01).

CONCLUSIONS

Sepsis was associated with NIV failure in patients with hypoxemic respiratory failure, and the association was stronger in septic shock patients. NIV failure increased with the increase of organ dysfunction caused by sepsis. The reviews of this paper are available via the supplemental material section.

Position Paper for the State-of-the-Art Application of Respiratory Support in Patients with COVID-19

Against the background of the pandemic caused by infection with the SARS-CoV-2 virus, the German Respiratory Society has appointed experts to develop therapy strategies for COVID-19 patients with acute respiratory failure (ARF). Here we present key position statements including observations about the pathophysiology of (ARF). In terms of the pathophysiology of pulmonary infection with SARS-CoV-2, COVID-19 can be divided into 3 phases. Pulmonary damage in advanced COVID-19 often differs from the known changes in acute respiratory distress syndrome (ARDS). Two types (type L and type H) are differentiated, corresponding to early- and late-stage lung damage. This differentiation should be taken into consideration in the respiratory support of ARF. The assessment of the extent of ARF should be based on arterial or capillary blood gas analysis under room air conditions, and it needs to include the calculation of oxygen supply (measured from the variables of oxygen saturation, hemoglobin level, the corrected values of Hüfner's factor, and cardiac output). Aerosols can cause transmission of infectious, virus-laden particles. Open systems or vented systems can increase the release of respirable particles. Procedures in which the invasive ventilation system must be opened and endotracheal intubation carried out are associated with an increased risk of infection. Personal protective equipment (PPE) should have top priority because fear of contagion should not be a primary reason for intubation. Based on the current knowledge, inhalation therapy, nasal high-flow therapy (NHF), continuous positive airway pressure (CPAP), or noninvasive ventilation (NIV) can be performed without an increased risk of infection to staff if PPE is provided. A significant proportion of patients with ARF present with relevant hypoxemia, which often cannot be fully corrected, even with a high inspired oxygen fraction (FiO2) under NHF. In this situation, the oxygen therapy can be escalated to CPAP or NIV when the criteria for endotracheal intubation are not met. In ARF, NIV should be carried out in an intensive care unit or a comparable setting by experienced staff. Under CPAP/NIV, a patient can deteriorate rapidly. For this reason, continuous monitoring and readiness for intubation are to be ensured at all times. If the ARF progresses under CPAP/NIV, intubation should be implemented without delay in patients who do not have a "do not intubate" order.

Consequences and Solutions for the Impact of Communication Impairment on Noninvasive Ventilation Therapy for Acute Respiratory Failure: A Focused Review

Objectives:

With over 2 million cases of acute respiratory failure in the United States per year, noninvasive ventilation has become a leading treatment modality, often supplanting invasive mechanical ventilation as the initial treatment of choice. Most acute respiratory failure patients use a full face (oronasal) mask with noninvasive ventilation, which is known to impair communication, but its popularity and benefit has led many providers to accept the communication impairment. Medical staff periodically remove masks to communicate with patients, but patients are often limited to short utterances and risk lung derecruitment upon removal of positive pressure. These problems can lead to noninvasive ventilation failure, which is often linked to worse outcomes than first initiating invasive mechanical ventilation and can lead to increased hospitalization costs.

Data Sources:

We searched MEDLINE and Google Scholar for “speech,” “communication,” “impairment,” “failure,” “complications,” “NIPPV,” “NIV,” and “noninvasive ventilation.”

Study Selection:

We included articles with patients in acute respiratory failure. We excluded articles for patients using noninvasive ventilation therapy for obstructive sleep apnea.

Data Synthesis:

Communication impairment has been associated with increasing noninvasive ventilation anxiety (odds ratio, 1.25). Of patients using noninvasive ventilation, 48% require early discontinuation, 22% refuse noninvasive ventilation, and 9% are ultimately intubated. Improvements to communication have been shown to reduce fear and anxiety in invasive mechanical ventilation patients. Analogous communication problems exist with effective solutions in other fields, such as fighter pilot masks, that can be easily implemented to enhance noninvasive ventilation patient care, increase adherence to noninvasive ventilation treatment, and improve patient outcomes.

Conclusions:

Communication impairment is an underappreciated cause of noninvasive ventilation complications and failure and requires further characterization. Analogous solutions—such as throat microphones and mask-based microphones—that can be easily implemented show potential as cost-effective methods to reduce noninvasive ventilation failure.

[Position Paper for the State of the Art Application of Respiratory Support in Patients with COVID-19 - German Respiratory Society]

Against the background of the pandemic caused by infection with the SARS-CoV-2, the German Society for Pneumology and Respiratory Medicine (DGP e.V.), in cooperation with other associations, has designated a team of experts in order to answer the currently pressing questions about therapy strategies in dealing with COVID-19 patients suffering from acute respiratory insufficiency (ARI).The position paper is based on the current knowledge that is evolving daily. Many of the published and cited studies require further review, also because many of them did not undergo standard review processes.Therefore, this position paper is also subject to a continuous review process and will be further developed in cooperation with the other professional societies.This position paper is structured into the following five topics:1. Pathophysiology of acute respiratory insufficiency in patients without immunity infected with SARS-CoV-22. Temporal course and prognosis of acute respiratory insufficiency during the course of the disease3. Oxygen insufflation, high-flow oxygen, non-invasive ventilation and invasive ventilation with special consideration of infectious aerosol formation4. Non-invasive ventilation in ARI5. Supply continuum for the treatment of ARIKey points have been highlighted as core statements and significant observations. Regarding the pathophysiological aspects of acute respiratory insufficiency (ARI), the pulmonary infection with SARS-CoV-2 COVID-19 runs through three phases: early infection, pulmonary manifestation and severe hyperinflammatory phase.There are differences between advanced COVID-19-induced lung damage and those changes seen in Acute Respiratory Distress Syndromes (ARDS) as defined by the Berlin criteria. In a pathophysiologically plausible - but currently not yet histopathologically substantiated - model, two types (L-type and H-type) are distinguished, which correspond to an early and late phase. This distinction can be taken into consideration in the differential instrumentation in the therapy of ARI.The assessment of the extent of ARI should be carried out by an arterial or capillary blood gas analysis under room air conditions and must include the calculation of the oxygen supply (measured from the variables of oxygen saturation, the Hb value, the corrected values of the Hüfner number and the cardiac output). In principle, aerosols can cause transmission of infectious viral particles. Open systems or leakage systems (so-called vented masks) can prevent the release of respirable particles. Procedures in which the invasive ventilation system must be opened, and endotracheal intubation must be carried out are associated with an increased risk of infection.The protection of personnel with personal protective equipment should have very high priority because fear of contagion must not be a primary reason for intubation. If the specifications for protective equipment (eye protection, FFP2 or FFP-3 mask, gown) are adhered to, inhalation therapy, nasal high-flow (NHF) therapy, CPAP therapy or NIV can be carried out according to the current state of knowledge without increased risk of infection to the staff. A significant proportion of patients with respiratory failure presents with relevant hypoxemia, often also caused by a high inspiratory oxygen fraction (FiO2) including NHF, and this hypoxemia cannot be not completely corrected. In this situation, CPAP/NIV therapy can be administered under use of a mouth and nose mask or a respiratory helmet as therapy escalation, as long as the criteria for endotracheal intubation are not fulfilled.In acute hypoxemic respiratory insufficiency, NIV should be performed in an intensive care unit or in a comparable unit by personnel with appropriate expertise. Under CPAP/NIV, a patient can deteriorate rapidly. For this reason, continuous monitoring with readiness to carry out intubation must be ensured at all times. If CPAP/NIV leads to further progression of ARI, intubation and subsequent invasive ventilation should be carried out without delay if no DNI order is in place.In the case of patients in whom invasive ventilation, after exhausting all guideline-based measures, is not sufficient, extracorporeal membrane oxygenation procedure (ECMO) should be considered to ensure sufficient oxygen supply and to remove CO2.

Use, timing and factors associated with tracheal intubation in septic shock: a prospective multicentric observational study

Background

No recommendation exists about the timing and setting for tracheal intubation and mechanical ventilation in septic shock.

Patients and methods

This prospective multicenter observational study was conducted in 30 ICUs in France and Spain. All consecutive patients presenting with septic shock were eligible. The use of tracheal intubation was described across the participating ICUs. A multivariate analysis was performed to identify parameters associated with early intubation (before H8 following vasopressor onset).

Results

Eight hundred and fifty-nine patients were enrolled. Two hundred and nine patients were intubated early (24%, range 4.5–47%), across the 18 centers with at least 20 patients included. The cumulative intubation rate during the ICU stay was 324/859 (38%, range 14–65%). In the multivariate analysis, seven parameters were significantly associated with early intubation and ranked as follows by decreasing weight: Glasgow score, center effect, use of accessory respiratory muscles, lactate level, vasopressor dose, pH and inability to clear tracheal secretions. Global R-square of the model was only 60% indicating that 40% of the variability of the intubation process was related to other parameters than those entered in this analysis.

Conclusion

Neurological, respiratory and hemodynamic parameters only partially explained the use of tracheal intubation in septic shock patients. Center effect was important. Finally, a vast part of the variability of intubation remained unexplained by patient characteristics.

Trial registration Clinical trials NCT02780466, registered on May 23, 2016. https://clinicaltrials.gov/ct2/show/NCT02780466?term=intubatic&draw=2&rank=1.

Severe diffuse alveolar hemorrhage related to autoimmune disease: a multicenter study

BACKGROUND

Diffuse alveolar hemorrhage (DAH) occurs during the course of autoimmune disease and may be life threatening. The objective was to assess characteristics and prognosis factors of DAH who required intensive care unit (ICU) admission in patients with autoimmune diseases.

METHODS

French multicenter retrospective study including patients presenting DAH related to autoimmune diseases requiring ICU admission from 2000 to 2016.

RESULTS

One hundred four patients (54% of men) with median age of 56 [32-68] years were included with 79 (76%) systemic vasculitis and 25 (24%) connective tissue disorders. All patients received steroids, and 72 (69%), 12 (11.5%), and 57 (55%) patients had cyclophosphamide, rituximab, and plasma exchanges, respectively. During ICU stay, 52 (50%), 36 (35%), and 55 (53%) patients required mechanical ventilation, vasopressor use, and renal replacement therapy, respectively. Factors associated with mechanical ventilation weaning were age (HR [95%CI] 0.97 [0.96-0.99] per 10 years, p < 0.0001), vasculitis-related DAH (0.52 [0.27-0.98], p = 0.04), and time from dyspnea onset to ICU admission (0.99 [0.99-1] per day, p = 0.03). ICU mortality was 15%. Factors associated with alive status at ICU discharge were chronic cardiac failure (HR [95%CI] 0.37 [0.15-0.94], p = 0.04), antiphospholipid syndrome-related DAH (3.17 [1.89-5.32], p < 0.0001), SAPS II (0.98 [0.97-0.99], p = 0.007), and oxygen flow at ICU admission (0.95 [0.91-0.99] per liter/min, p = 0.04).

CONCLUSION

DAH in autoimmune diseases is a life-threatening complication which requires mechanical ventilation in half of the cases admitted to ICU.

Trends in mechanical ventilation use and mortality over time in patients receiving mechanical ventilation in Spain from 2001 to 2015

BACKGROUND

We examined trends in the incidence of ventilator support with noninvasive ventilation (NIV) or invasive mechanical ventilation (IMV) among patients hospitalized in Spain from 2001 to 2015. We also assessed in-hospital mortality (IHM) after receiving these types of ventilator support.

METHODS

This study was an observational retrospective epidemiological study. Our data source was the Spanish National Hospital Discharge Database.

RESULTS

In total, 1,031,497 patients received ventilator support in Spain over the study period. NIV use increased from 18.8 patients per 100.000 inhabitants in 2001 to 108.7 in 2015. IMV utilization increased significantly from 2001 to 2003 and then decreased from 2003 until 2015. Patients who required NIV had the highest mean Charlson Comorbidity Index (CCI) score. Patients who received IMV had the highest in-hospital mortality. Factors associated with an increased risk for IHM were sex, age, conditions included in the CCI (except for COPD and diabetes), haemodialysis, presence of a peripheral arterial catheter, presence of a central venous catheter, readmission and emergency room admission. Undergoing a surgical procedure was a risk factor only for IMV. IHM decreased significantly from 2001 to 2015 in patients who underwent NIV or IMV.

CONCLUSIONS

We identified an increase in the utilization of NIV over time, whereas use of IMV decreased from 2003 until 2015 after an initial increase from 2001 to 2003. We also found a significant decrease in IHM over time.

Diagnostic Accuracy of Diaphragm Ultrasound in Detecting and Characterizing Patient-Ventilator Asynchronies during Noninvasive Ventilation

BACKGROUND

Management of acute respiratory failure by noninvasive ventilation is often associated with asynchronies, like autotriggering or delayed cycling, incurred by leaks from the interface. These events are likely to impair patient's tolerance and to compromise noninvasive ventilation. The development of methods for easy detection and monitoring of asynchronies is therefore necessary. The authors describe two new methods to detect patient-ventilator asynchronies, based on ultrasound analysis of diaphragm excursion or thickening combined with airway pressure. The authors tested these methods in a diagnostic accuracy study.

METHODS

Fifteen healthy subjects were placed under noninvasive ventilation and subjected to artificially induced leaks in order to generate the main asynchronies (autotriggering or delayed cycling) at event-appropriate times of the respiratory cycle. Asynchronies were identified and characterized by conjoint assessment of ultrasound records and airway pressure waveforms; both were visualized on the ultrasound screen. The performance and accuracy of diaphragm excursion and thickening to detect each asynchrony were compared with a "control method" of flow/pressure tracings alone, and a "working standard method" combining flow, airway pressure, and diaphragm electromyography signals analyses.

RESULTS

Ultrasound recordings were performed for the 15 volunteers, unlike electromyography recordings which could be collected in only 9 of 15 patients (60%). Autotriggering was correctly identified by continuous recording of electromyography, excursion, thickening, and flow/pressure tracings with sensitivity of 93% (95% CI, 89-97%), 94% (95% CI, 91-98%), 91% (95% CI, 87-96%), and 79% (95% CI, 75-84%), respectively. Delayed cycling was detected by electromyography, excursion, thickening, and flow/pressure tracings with sensitivity of 84% (95% CI, 77-90%), 86% (95% CI, 80-93%), 89% (95% CI, 83-94%), and 67% (95% CI, 61-73%), respectively.

CONCLUSIONS

Ultrasound is a simple, bedside adjustable, clinical tool to detect the majority of patient-ventilator asynchronies associated with noninvasive ventilation leaks, provided that it is possible to visualize the airway pressure curve on the ultrasound machine screen. Ultrasound detection of autotriggering and delayed cycling is more accurate than isolated observation of pressure and flow tracings, and more feasible than electromyogram.

Dose-response characteristics of noninvasive ventilation in acute respiratory failure

Acute noninvasive ventilation (NIV) is a well-established therapy for acute respiratory failure but the dose–response characteristics of this therapy have not been defined. The aim of this study was to define this dose–response relationship.

This study was a retrospective review of patients receiving NIV for acute respiratory failure in a tertiary hospital respiratory high-dependency unit between July 2012 and June 2017. Mask-on time (rather than the period that NIV was in use) as the “dose” was compared with hospital survival as the “response”.

654 patients were included, 594 (91%) with hypercapnic respiratory failure (HCRF). NIV was used for a median (interquartile range (IQR)) duration of 2.74 (1.51–4.73) days and median (IQR) mask-on time was 34 (18–60) h (56.1% (41.2–69.5%) of treatment time). There was evidence of a dose–response relationship in the HCRF group up to a ceiling of 24 h mask-on time, but not in the hypoxaemic respiratory failure (HRF) group. There was a difference in survival with as little as 2 h mask-on time (92% compared with 73%; p<0.001). Patients requiring NIV for 80–100% of therapy time had lower survival.

We conclude that there is evidence of a dose–response relationship between cumulative NIV usage (mask-on time) and survival from as little as 2 h to a ceiling of ∼24 h in HCRF, but not in HRF.

Acute NIV in respiratory failure has a dose–response effect on survival from as little as 2 h of therapyhttp://bit.ly/2okErQZ

ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs

A. ACUTE HYPERCAPNIC RESPIRATORY FAILURE A1. Acute Exacerbation of COPD: Recommendations: NIV should be used in management of acute exacerbation of COPD in patients with acute or acute-on-chronic respiratory acidosis (pH = 7.25-7.35). (1A) NIV should be attempted in patients with acute exacerbation of COPD (pH <7.25 & PaCO2 ≥ 45) before initiating invasive mechanical ventilation (IMV) except in patients requiring immediate intubation. (2A). Lower the pH higher the chance of failure of NIV. (2B) NIV should not to be used routinely in normo- or mildly hyper-capneic patients with acute exacerbation of COPD, without acidosis (pH > 7.35). (2B) A2. NIV in ARF due to Chest wall deformities/Neuromuscular diseases: Recommendations: NIV may be used in patients of ARF due to chest wall deformity/Neuromuscular diseases. (PaCO2 ≥ 45) (UPP) A3. NIV in ARF due to Obesity hypoventilation syndrome (OHS): Recommendations: NIV may be used in AHRF in OHS patients when they present with acute hypercapnic or acute on chronic respiratory failure (pH 45). (3B) NIV/CPAP may be used in obese, hypercapnic patients with OHS and/or right heart failure in the absence of acidosis. (UPP) B. NIV IN ACUTE HYPOXEMIC RESPIRATORY FAILURE: B1. NIV in Acute Cardiogenic Pulmonary Oedema: Recommendations: NIV is recommended in hospital patients with ARF, due to Cardiogenic pulmonary edema. (1A). NIV should be used in patients with acute heart failure/ cardiogenic pulmonary edema, right from emergency department itself. (1B) Both CPAP and BiPAP modes are safe and effective in patients with cardiogenic pulmonary edema. (1A). However, BPAP (NIV-PS) should be preferred in cardiogenic pulmonary edema with hypercapnia. (3A) B2. NIV in acute hypoxemic respiratory failure: Recommendations: NIV may be used over conventional oxygen therapy in mild early acute hypoxemic respiratory failure (P/F ratio <300 and >200 mmHg), under close supervision. (2B) We strongly recommend against a trial of NIV in patients with acute hypoxemic failure with P/F ratio <150. (2A) B3. NIV in ARF due to Chest Trauma: Recommendations: NIV may be used in traumatic flail chest along with adequate pain relief. (3B) B4. NIV in Immunocompromised Host: Recommendations: In Immunocompromised patients with early ARF, we may consider NIV over conventional oxygen. (2B). B5. NIV in Palliative Care: Recommendations: We strongly recommend use of NIV for reducing dyspnea in palliative care setting. (2A) B6. NIV in post-operative cases: Recommendations: NIV should be used in patients with post-operative acute respiratory failure. (2A) B6a. NIV in abdominal surgery: Recommendations: NIV may be used in patients with ARF following abdominal surgeries. (2A) B6b. NIV in bariatric surgery: Recommendations: NIV may be used in post-bariatric surgery patients with pre-existent OSA or OHS. (3A) B6c. NIV in Thoracic surgery: Recommendations: In cardiothoracic surgeries, use of NIV is recommended post operatively for acute respiratory failure to improve oxygenation and reduce chance of reintubation. (2A) NIV should not be used in patients undergoing esophageal surgery. (UPP) B6d. NIV in post lung transplant: Recommendations: NIV may be used for shortening weaning time and to avoid re-intubation following lung transplantation. (2B) B7. NIV during Procedures (ETI/Bronchoscopy/TEE/Endoscopy): Recommendations: NIV may be used for pre-oxygenation before intubation. (2B) NIV with appropriate interface may be used in patients of ARF during Bronchoscopy/Endoscopy to improve oxygenation. (3B) B8. NIV in Viral Pneumonitis ARDS: Recommendations: NIV cannot be considered as a treatment of choice for patients with acute respiratory failure with H1N1 pneumonia. However, it may be reasonable to use NIV in selected patients with single organ involvement, in a strictly controlled environment with close monitoring. (2B) B9. NIV and Acute exacerbation of Pulmonary Tuberculosis: Recommendations: Careful use of NIV in patients with acute Tuberculosis may be considered, with effective infection control precautions to prevent air-borne transmission. (3B) B10. NIV after planned extubation in high risk patients: Recommendation: We recommend that NIV may be used to wean high risk patients from invasive mechanical ventilation as it reduces re-intubation rate. (2B) B11. NIV for respiratory distress post extubation: Recommendations: We recommend that NIV therapy should not be used to manage respiratory distress post-extubation in high risk patients. (2B) C. APPLICATION OF NIV: Recommendation: Choice of mode should be mainly decided by factors like disease etiology and severity, the breathing effort by the patient and the operator familiarity and experience. (UPP) We suggest using flow trigger over pressure triggering in assisted modes, as it provides better patient ventilator synchrony. Especially in COPD patients, flow triggering has been found to benefit auto PEEP. (3B) D. MANAGEMENT OF PATIENT ON NIV: D1. Sedation: Recommendations: A non-pharmacological approach to calm the patient (Reassuring the patient, proper environment) should always be tried before administrating sedatives. (UPP) In patients on NIV, sedation may be used with extremely close monitoring and only in an ICU setting with lookout for signs of NIV failure. (UPP) E. EQUIPMENT: Recommendations: We recommend that portable bilevel ventilators or specifically designed ICU ventilators with non-invasive mode should be used for delivering Non–invasive ventilation in critically ill patients. (UPP) Both critical care ventilators with leak compensation and bi-level ventilators have been equally effective in decreasing the WOB, RR, and PaCO2. (3B) Currently, Oronasal mask is the most preferred interface for non-invasive ventilation for acute respiratory failure. (3B) F. WEANING: Recommendations: We recommend that weaning from NIV may be done by a standardized protocol driven approach of the unit. (2B)

How to cite this article: Chawla R, Dixit SB, Zirpe KG, Chaudhry D, Khilnani GC, Mehta Y, et al. ISCCM Guidelines for the Use of Non-invasive Ventilation in Acute Respiratory Failure in Adult ICUs. Indian J Crit Care Med 2020;24(Suppl 1):S61–S81.

Indications for Non-Invasive Ventilation in Respiratory Failure

BACKGROUND

Non-invasive ventilation (NIV) is increasingly being used to treat episodes of acute respiratory failure not only in critical care and respiratory wards, but also in emergency departments.

AIM

Aim of this review is to summarize the current indications for the management of NIV for respiratory failure.

METHODS

Current literature about the topic was reviewed and critically reported to describe the rationale and physiologic advantages of NIV in various situations of respiratory failure.

RESULTS

Early NIV use is commonly associated with the significant decrease in endotracheal intubation rate, the incidence of infective complications (especially ventilatory associated pneumonia), Intensive Care Units and the length of hospital stay and, in selected conditions, also in mortality rates. Severe acute exacerbation of chronic obstructive pulmonary disease (pH<7.35 and relative hypercarbia) and acute cardiogenic pulmonary oedema are the most common NIV indications; in these conditions NIV advantages are clearly documented. Not so evident are the NIV benefits in hypoxaemic respiratory failure occurring without prior chronic respiratory disease (De novo respiratory failure). One recent randomized control trial reported in hypoxaemic respiratory failure a survival benefit of high-flow nasal cannulae over standard oxygen therapy and bilevel NIV. Evidence suggests the advantages of NIV also in respiratory failure in immunocompromised patients or chest trauma patients. Use during a pandemic event has been assessed in several observational studies but remains controversial; there also is not sufficient evidence to support the use of NIV treatment in acute asthma exacerbation.

CONCLUSION

NIV eliminates morbidity related to the endotracheal tube (loss of airway defense mechanism with increased risk of pneumonia) and in selected conditions (COPD exacerbation, acute cardiogenic pulmonary edema, immunosuppressed patients with pulmonary infiltrates and hypoxia) is clearly associated with a better outcome in comparison to conventional invasive ventilation. However, NIV is associated with complications, especially minor complications related to interface. Major complications like aspiration pneumonia, barotrauma and hypotension are infrequent.

Noninvasive Ventilation for Critically Ill Subjects With Acute Respiratory Failure in the Emergency Department

BACKGROUND

We aimed to investigate the association between noninvasive ventilation (NIV) initiated in the emergency department and patient outcomes for those requiring invasive mechanical ventilation so that we could understand the effect of extended NIV use (ie, > 4 h) prior to invasive mechanical ventilation on patient outcomes.

METHODS

We conducted a retrospective single-center cohort study at an academic tertiary care hospital center. All emergency department patients with acute respiratory failure requiring invasive mechanical ventilation and admission to the ICU within 48 h of initial presentation over a 24-month period were included.

RESULTS

Subject characteristics, ventilator parameters, and clinical course were captured via electronic query, respiratory billing data, and standardized chart abstraction. A total of 431 subjects with acute respiratory failure requiring invasive mechanical ventilation within 48 h of arrival were identified, of whom 115 (26.7%) were exposed to NIV prior to invasive mechanical ventilation, with a median duration of 4 h (interquartile range 1.9-9.3). Based on a multivariable model controlling for covariates, any NIV exposure prior to invasive mechanical ventilation was not associated with an increased odds of persistent organ dysfunction or death. However, in the subset of subjects exposed to NIV, extended NIV use (ie, > 4 h) prior to invasive mechanical ventilation was associated with increased odds of persistent organ dysfunction or death (odds ratio 4.11, 95% CI 1.51-11.19). Extended NIV use was also associated with increased odds of in-hospital mortality (odds ratio 4.02, 95% CI 1.51-10.74).

CONCLUSIONS

Although any exposure to NIV prior to invasive mechanical ventilation did not appear to affect morbidity and mortality, extended NIV use prior to invasive mechanical ventilation was associated with worse patient outcomes, suggesting a need for additional study to better understand the ramifications of duration of NIV use prior to failure on outcomes. Given this early timeframe for intervention, future studies should be collaborations between the emergency department and ICU.

Pneumonia

Pneumonia is a common cause of hospital admission and community-acquired pneumonia (CAP) is a growing health problem in developed country and worldwide. Elderly patients suffer from more severe disease, require intensive care unit (ICU) admission, and exhibit higher mortality compared with their younger counterparts. The immunological changes that occur with age called “immunosenescence” (decreased efficiency of the adaptive and innate immune systems) are known to be responsible for the increased susceptibility of elderly persons to infectious diseases and for their limited response to vaccines [1].

Efficacy of protocol-based non-invasive positive pressure ventilation for acute respiratory distress syndrome: a retrospective observational study

Aim

The efficacy of non-invasive positive pressure ventilation (NPPV) in acute respiratory distress syndrome (ARDS) remains unclear. Variation in both the etiology of ARDS and patient factors has resulted in inconsistent application of NPPV. We have developed a protocol-based NPPV strategy as a first-line intervention for ARDS. The aim of this observational study was to determine if protocol-based NPPV improves the outcome in patients with ARDS.

Methods

We identified patients with ARDS treated by protocol-based NPPV at our institution between March 2006 and March 2010 and categorized them according to NPPV success or failure. Success was defined as avoidance of intubation and remaining alive during NPPV.

Results

Eighty-eight of 169 patients diagnosed with ARDS during the study period were treated using the protocol. Fifty-two (76%) of 68 patients who were eligible for the study were successfully treated and did not require endotracheal intubation. The overall mortality rate at 28 days after initiation of NPPV was 12%. The mortality rate was significantly lower in the success group than in the failure group (P < 0.01). The PaO₂/FiO₂ ratio after 12-24 h of NPPV was significantly higher in the success group than in the failure group (202 ± 63 versus 145 ± 46; P < 0.01).

Conclusions

The success rate was higher and the mortality was lower in patients than in historical controls. Protocol-based NPPV could be effective in patients with ARDS.

Breathing variability predicts the suggested need for corrective intervention due to the perceived severity of patient-ventilator asynchrony during NIV

Patient-ventilator asynchrony is associated with intolerance to noninvasive ventilation (NIV) and worsened outcomes. Our goal was to develop a tool to determine a patient needs for  intervention by a practitioner due to the presence of patient-ventilator asynchrony. We postulated that a clinician can determine when a patient needs corrective intervention due to the perceived severity of patient-ventilator asynchrony. We hypothesized a new measure, patient breathing variability, would indicate when corrective intervention is suggested by a bedside practitioner due to the perceived severity of patient-ventilator asynchrony. With IRB approval data was collected on 78 NIV patients. A panel of experts reviewed retrospective data from a development set of 10 NIV patients to categorize them into one of the three categories. The three categories were; "No to mild asynchrony-no intervention needed", "moderate asynchrony-non-emergent corrective intervention required", and "severe asynchrony-immediate intervention required". A stepwise regression with a F-test forward selection criterion was used to develop a positive linear logic model predicting the expert panel's categorizations of the need for corrective intervention. The model was incorporated into a software tool for clinical implementation. The tool was implemented prospectively on 68 NIV patients simultaneous to a bedside practitioner scoring the need for corrective intervention due to the perceived severity of patient-ventilator asynchrony. The categories from the tool and the practitioner were compared with the rate of agreement, sensitivity, specificity, and receiver operator characteristic analyses. The rate of agreement in categorizing the suggested need for clinical intervention due to the perceived presence of patient-ventilator asynchrony between the tool and experienced bedside practitioners was 95% with a Kappa score of 0.85 (p < 0.001). Further analysis found a specificity of 84% and sensitivity of 99%. The tool appears to accurately match the suggested need for corrective intervention by a bedside practitioner. Application of the tool allows for continuous, real time, and non-invasive monitoring of patients receiving NIV, and may enable early corrective interventions to ameliorate potential patient-ventilator asynchrony.

One-Year Outcomes in Patients With Acute Respiratory Distress Syndrome Enrolled in a Randomized Clinical Trial of Helmet Versus Facemask Noninvasive Ventilation

OBJECTIVES

Many survivors of acute respiratory distress syndrome have poor long-term outcomes possibly due to supportive care practices during "invasive" mechanical ventilation. Helmet noninvasive ventilation in acute respiratory distress syndrome may reduce intubation rates; however, it is unknown if avoiding intubation with helmet noninvasive ventilation alters the consequences of surviving acute respiratory distress syndrome.

DESIGN

Long-term follow-up data from a previously published randomized controlled trial.

PATIENTS

Adults patients with acute respiratory distress syndrome enrolled in a previously published clinical trial.

SETTING

Adult ICU.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was functional independence at 1 year after hospital discharge defined as independence in activities of daily living and ambulation. At 1 year, patients were surveyed to assess for functional independence, survival, and number of institution-free days, defined as days alive spent living at home. The presence of ICU-acquired weakness and functional independence was also assessed by a blinded therapist on hospital discharge. On hospital discharge, there was a greater prevalence of ICU-acquired weakness (79.5% vs 38.6%; p = 0.0002) and less functional independence (15.4% vs 50%; p = 0.001) in the facemask group. One-year follow-up data were collected for 81 of 83 patients (97.6%). One-year mortality was higher in the facemask group (69.2% vs 43.2%; p = 0.017). At 1 year, patients in the helmet group were more likely to be functionally independent (40.9% vs 15.4%; p = 0.015) and had more institution-free days (median, 268.5 [0-354] vs 0 [0-323]; p = 0.017).

CONCLUSIONS

Poor functional recovery after invasive mechanical ventilation for acute respiratory distress syndrome is common. Helmet noninvasive ventilation may be the first intervention that mitigates the long-term complications that plague survivors of acute respiratory distress syndrome managed with noninvasive ventilation.

Outcomes of Noninvasive Positive Pressure Ventilation in Acute Respiratory Distress Syndrome and Their Predictors: A National Cohort

Rationale

Although noninvasive positive pressure ventilation (NIPPV) is increasingly used in acute respiratory distress syndrome (ARDS) to avoid invasive mechanical ventilation (IMV), the data supporting its benefit for this indication are lacking.

Objectives

To analyze the all-cause in-hospital mortality rate and length of stay (LOS) for ARDS patients who received NIPPV in the United States (US) compared to those who were initially intubated. Our secondary outcome of interest was to determine the predicting factors for NIPPV failure.

Methods

We used the 2016 National Inpatient Sample database to identify 4,277 adult records with ARDS who required positive pressure ventilation. We divided the cohort into initial treatment with IMV or NIPPV. Then, the NIPPV group was further subdivided into NIPPV failure or success. We defined NIPPV failure as same-patient use of NIPPV and IMV either on the same day or using IMV at a later date. We analyzed the in-hospital mortality, LOS, and NIPPV failure rate. Linear regression of log-transformed LOS and logistic regression of binary outcomes were used to test for associations.

Results

The NIPPV success group had the lowest mortality rate (4.9% [3.8, 6.4]) and the shortest LOS (7 days [6.6, 7.5]). The NIPPV failure rate was 21%. Sepsis, pneumonia, and chronic liver disease were associated with higher odds of NIPPV failure (adjusted OR: 4.47, 2.65, and 2.23, respectively). There was no significant difference between NIPPV failure and IMV groups in-hospital mortality (26.9% [21.8, 32.8] vs. 25.1% [23.5, 26.9], p=0.885) or LOS (16 [14, 18] vs. 15.6 [15, 16.3], p=0.926).

Conclusions

NIPPV success in ARDS exhibits significantly lower hospital mortality rates and shorter LOS compared with IMV, and NIPPV failure exhibits no significant difference in hospital mortality or LOS compared with patients who were initially intubated. Therefore, an initial trial of NIPPV may be considered in ARDS. Sepsis, pneumonia, and chronic liver disease were associated with higher odds of NIPPV failure; these factors should be used to stratify patients to the most suitable ventilation modality.

Feasibility of Early Noninvasive Ventilation Strategy for Patients with Acute Onset Shortness of Breath in Emergency Department — A Prospective Interventional Study

Introduction

Noninvasive ventilation (NIV) has revolutionized the initial respiratory support provided to a patient in respiratory distress presenting to emergency department. Standardization of NIV practices and safety has always been a matter of concern and debate in emergency medicine. In this study, we tried to assess the clinical outcome of NIV in respiratory failures of varied etiologies.

Materials and methods

This study was conducted from August 2017 to August 2018 at our emergency department which is a tertiary care teaching institute. All patients presenting to the ED with shortness of breath were screened for acute respiratory failure and enrolled after confirming the inclusion criteria.

Results

Out of the 236 patients presenting with acute respiratory failure, 182 fulfilled the study criteria. However, 154 patients with a mean age of 55.19 + 16.73 years were enrolled in the study. Bilevel PAP was initiated in 103 patients whereas 51 patients received CPAP. 115 (74.67%) NIV trials were successful whereas 36 (23.37%) patients had to be intubated. 32 patients died among the study group among which 3 had not consented for intubation. The in-hospital mortality has been 20.77% whereas the percentage of NIV failure with consequent intubation was 25.32%.

Conclusion

In conclusion, our study shows that NIV is not only safe and efficacious but also significantly brings down the requirement of endotracheal intubations and its complications provided proper patient selection and close monitoring is assured.

How to cite this article

Nizami MI, Sharma A, Jayaram K. Feasibility of Early Noninvasive Ventilation Strategy for Patients with Acute Onset Shortness of Breath in Emergency Department — A Prospective Interventional Study. Indian J Crit Care Med 2019;23(9):400–404.

Predictors of success of high-flow nasal cannula in the treatment of acute hypoxemic respiratory failure

BACKGROUND

High-flow nasal cannula (HFNC) therapy is used in the treatment of acute respiratory failure (ARF) and is both safe and effective in reversing hypoxemia. In order to minimize mortality and clinical complications associated to this practice, a series of tools must be developed to allow early detection of failure. The present study was carried out to: (i)examine the impact of respiratory rate (RR), peripheral oxygen saturation (SpO₂), ROX index (ROXI=[SpO₂/FiO₂]/RR) and oxygen inspired fraction (FiO₂) on the success of HFNC in patients with hypoxemic ARF; and (ii)analyze the length of stay and mortality in the ICU, and the need for mechanical ventilation (MV).

METHODS

A retrospective study was carried out in the medical-surgical ICU of Hospital de Montilla (Córdoba, Spain). Patients diagnosed with hypoxemic ARF and treated with HFNC from January 2016 to January 2018 were included.

RESULTS

Out of 27 patients diagnosed with ARF, 19 (70.37%) had hypoxemic ARF. Fifteen of them (78.95%) responded satisfactorily to HFNC, while four (21.05%) failed. After two hours of treatment, RR proved to be the best predictor of success (area under the ROC curve [AUROC] 0.858; 95%CI: 0.63-1.05; P=.035). For this parameter, the optimal cutoff point was 29rpm (sensitivity 75%, specificity 87%). After 8hours of treatment, FiO₂ and ROXI were reliable predictors of success (FiO₂: AUROC 0.95; 95%CI: 0.85-1.04; P=.007 and ROXI: AUROC 0.967; 95%CI: 0.886-1.047; P=.005). In the case of FiO₂ the optimal cutoff point was 0.59 (sensitivity 75%, specificity 93%), while the best cutoff point for ROXI was 5.98 (sensitivity 100%, specificity 75%). Using a Cox regression model, we found RR<29rpm after two hours of treatment, and FiO₂<0.59 and ROXI>5.98 after 8hours of treatment, to be associated with a lesser risk of MV (RR: HR 0.103; 95%CI: 0.11-0.99; P=.05; FiO₂: HR 0.053; 95%CI: 0.005-0.52; P=.012; and ROXI: HR 0.077; 95%CI: 0.008-0.755; P=.028, respectively).

CONCLUSIONS

RR after two hours of treatment, and FiO₂ and ROXI after 8hours of treatment, were the best predictors of success of HFNC. RR<29rpm, FiO₂<0.59 and ROXI>5.98 were associated with a lesser risk of MV.

Is immunosuppression status a risk factor for noninvasive ventilation failure in patients with acute hypoxemic respiratory failure? A post hoc matched analysis

Background

Recent European/American guidelines recommend noninvasive ventilation (NIV) as a first-line therapy to manage acute hypoxemic respiratory failure in immunocompromised patients. By contrast, NIV may have deleterious effects in nonimmunocompromised patients and experts have been unable to offer a recommendation. Immunocompromised patients have particularly high mortality rates when they require intubation. However, it is not clear whether immunosuppression status is a risk factor for NIV failure. We assessed the impact of immunosuppression status on NIV failure in a post hoc analysis pooling two studies including patients with de novo acute hypoxemic respiratory failure treated with NIV. Patients with hypercapnia, acute exacerbation of chronic lung disease, cardiogenic pulmonary edema, or with do-not-intubate order were excluded.

Results

Among the 208 patients included in the analysis, 71 (34%) were immunocompromised. They had higher severity scores upon ICU admission, higher pressure-support levels, and minute ventilation under NIV, and were more likely to have bilateral lung infiltrates than nonimmunocompromised patients. Intubation and in-ICU mortality rates were higher in immunocompromised than in nonimmunocompromised patients: 61% vs. 43% (p = 0.02) and 38% vs. 15% (p < 0.001), respectively. After adjustment or using a propensity score-matched analysis, immunosuppression was not associated with intubation, whereas it remained independently associated with ICU mortality with an adjusted odds ratio of 2.64 (95% CI 1.24–5.67, p = 0.01).

Conclusions

Immunosuppression status may directly influence mortality but does not seem to be associated with an increased risk of intubation in patients with de novo acute hypoxemic respiratory failure treated with NIV. Studies in this specific population are needed.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0566-z) contains supplementary material, which is available to authorized users.

Predictors of Intubation in Patients With Acute Hypoxemic Respiratory Failure Treated With a Noninvasive Oxygenation Strategy

OBJECTIVES

In patients with acute hypoxemic respiratory failure, noninvasive ventilation and high-flow nasal cannula oxygen are alternative strategies to conventional oxygen therapy. Endotracheal intubation is frequently needed in these patients with a risk of delay, and early predictors of failure may help clinicians to decide early. We aimed to identify factors associated with intubation in patients with acute hypoxemic respiratory failure treated with different noninvasive oxygenation techniques.

DESIGN

Post hoc analysis of a randomized clinical trial.

SETTING

Twenty-three ICUs.

PATIENTS

Patients with a respiratory rate greater than 25 breaths/min and a PaO2/FIO2 ratio less than or equal to 300 mm Hg.

INTERVENTION

Patients were treated with standard oxygen, high-flow nasal cannula oxygen, or noninvasive ventilation.

MEASUREMENT AND MAIN RESULTS

Respiratory variables one hour after treatment initiation. Under standard oxygen, patients with a respiratory rate greater than or equal to 30 breaths/min were more likely to need intubation (odds ratio, 2.76; 95% CI, 1.13-6.75; p = 0.03). One hour after high-flow nasal cannula oxygen initiation, increased heart rate was the only factor associated with intubation. One hour after noninvasive ventilation initiation, a PaO2/FIO2 ratio less than or equal to 200 mm Hg and a tidal volume greater than 9 mL/kg of predicted body weight were independent predictors of intubation (adjusted odds ratio, 4.26; 95% CI, 1.62-11.16; p = 0.003 and adjusted odds ratio, 3.14; 95% CI, 1.22-8.06; p = 0.02, respectively). A tidal volume above 9 mL/kg during noninvasive ventilation remained independently associated with 90-day mortality.

CONCLUSIONS

In patients with acute hypoxemic respiratory failure breathing spontaneously, the respiratory rate was a predictor of intubation under standard oxygen, but not under high-flow nasal cannula oxygen or noninvasive ventilation. A PaO2/FIO2 below 200 mm Hg and a high tidal volume greater than 9 mL/kg were the two strong predictors of intubation under noninvasive ventilation.

High flow nasal cannula oxygen therapy versus non-invasive ventilation for chronic obstructive pulmonary disease with acute-moderate hypercapnic respiratory failure: an observational cohort study

Background

High-flow nasal cannula (HFNC) oxygen therapy in acute hypoxic respiratory failure is becoming increasingly popular. However, evidence to support the use of HFNC in acute respiratory failure (ARF) with hypercapnia is limited.

Methods

Chronic obstructive pulmonary disease (COPD) patients with moderate hypercapnic ARF (arterial blood gas pH 7.25–7.35, PaCO₂>50 mmHg) who received HFNC or non-invasive ventilation (NIV) in the intensive care uint from April 2016 to March 2018 were analyzed retrospectively. The endpoint was treatment failure, defined as either invasive ventilation, or a switch to the other study treatment (NIV for patients in the NFNC group, and vice-versa), and 28-day mortality.

Results

Eighty-two COPD patients (39 in the HFNC group and 43 in the NIV group) were enrolled in this study. The mean age was 71.8±8.2 and 54 patients (65.9%) were male. The treatment failed in 11 out of 39 patients with HFNC (28.2%) and in 17 of 43 patients with NIV (39.5%) (P=0.268). No significant differences were found for 28-day mortality (15.4% in the HFNC group and 14% in the NIV group, P=0.824). During the first 24 hrs of treatment, the number of nursing airway care interventions in the HFNC group was significantly less than in the NIV group, while the duration of device application was significantly longer in the HFNC group (all P<0.05). Skin breakdown was significantly more common in the NIV group (20.9% vs 5.1%, P<0.05).

Conclusion

Among COPD patients with moderate hypercarbic ARF, the use of HFNC compared with NIV did not result in increased rates of treatment failure, while there were fewer nursing interventions and skin breakdown episodes reported in the HFNC group.