The challenge of avoiding intubation in immunocompromised patients with acute respiratory failure

Outcomes in immunocompromised patients with acute hypoxemic respiratory failure treated by high-flow nasal oxygen

PURPOSE

Acute hypoxemic respiratory failure (ARF) is a major challenge in immunocompromised patients, often complicated by severe respiratory distress and organ dysfunction. High-flow nasal oxygen (HFNO) therapy is the standard of care, but data on its effectiveness and outcomes are limited. This study evaluated the outcomes of HFNO in this population, predictors of invasive mechanical ventilation (IMV), and factors associated with 28-day mortality.

METHODS

We analyzed data from a multicenter cohort of 986 immunocompromised patients with ARF treated with HFNO. Predictive factors for IMV and mortality were assessed using multivariable survival models, and the predictive value of the respiratory rate‑oxygenation (ROX) index for IMV was evaluated.

RESULTS

Patients had a median age of 63 years [IQR 54-70], and 66% were male. Primary causes of immunosuppression included hematologic malignancies (55%), solid tumors (30%), and solid-organ transplantation (10%). Bacterial pneumonia (40%) and opportunistic infections (15%) were the most common ARF etiologies. IMV was required in 46% of patients. Day 28 mortality was 33%, with better outcomes for solid-organ transplant recipients compared to hematologic malignancy or solid tumor (70% vs. 48% vs. 51% mortality, respectively). Predictors of IMV included a lower ROX index, higher respiratory rates, and lower PaO2/FiO2 ratios. Mortality was highest among patients requiring IMV, particularly those with myeloid malignancies or viral pneumonia.

CONCLUSIONS

HFNO outcomes in immunocompromised patients with ARF vary widely, influenced by immunosuppression type, ARF etiology, and clinical factors. Optimizing treatment and identifying high-risk patients could improve outcomes. Prospective studies are needed to enhance HFNO strategies.

Escalation of Oxygenation Modalities and Mortality in Critically Ill Immunocompromised Patient With Acute Hypoxemic Respiratory Failure: A Clustering Analysis of a Prospectively Multicenter, Multinational Dataset

OBJECTIVES

Acute hypoxemic respiratory failure in immunocompromised patients remains the leading cause of admission to the ICU, with high case fatality. The response to the initial oxygenation strategy may be predictive of outcome. This study aims to assess the response to the evolutionary profiles of oxygenation strategy and the association with survival.

DESIGN

Post hoc analysis of EFRAIM study with a nonparametric longitudinal clustering technique (longitudinal K-mean).

SETTING AND PATIENTS

Multinational, observational prospective cohort study performed in critically ill immunocompromised patients admitted for an acute respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 1547 patients who did not require invasive mechanical ventilation (iMV) at ICU admission were included. Change in ventilatory support was assessed and three clusters of change in oxygenation modality over time were identified. Cluster A: 12.3% iMV requirement and high survival rate, n = 717 patients (46.3%); cluster B: 32.9% need for iMV, 97% ICU mortality, n = 499 patients (32.3%); and cluster C: 37.5% need for iMV, 0.3% ICU mortality, n = 331 patients (21.4%). These clusters demonstrated a high discrimination. After adjustment for confounders, clusters B and C were independently associated with need for iMV (odds ratio [OR], 9.87; 95% CI, 7.26-13.50 and OR, 19.8; 95% CI, 13.7-29.1).

CONCLUSIONS

This study identified three distinct highly performing clusters of response to initial oxygenation strategy, which reliably predicted the need for iMV requirement and hospital mortality.

Management of analgosedation during noninvasive respiratory support: an expert Delphi consensus document developed by the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care (SIAARTI)

BACKGROUND

Discomfort can be the cause of noninvasive respiratory support (NRS) failure in up to 50% of treated patients. Several studies have shown how analgosedation during NRS can reduce the rate of delirium, endotracheal intubation, and hospital length of stay in patients with acute respiratory failure. The purpose of this project was to explore consensus on which medications are currently available as analgosedatives during NRS, which types of patients may benefit from analgosedation while on NRS, and which clinical settings might be appropriate for the implementation of analgosedation during NRS.

METHODS

The Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care (SIAARTI) selected a panel of experts and asked them to define key aspects of the use of analgesics and sedatives during NRS treatment. The methodology applied is in line with the principles of the modified Delphi and RAND-UCLA methods. The experts developed statements and supportive rationales which were then subjected to blind votes for consensus.

RESULTS

The use of an analgosedation strategy in adult patients with acute respiratory failure of different origins may be useful where there is a need to manage discomfort. This strategy should be considered after careful assessment of other potential factors associated with respiratory failure or inappropriate noninvasive respiratory support settings, which may, in turn, be responsible for NRS failure. Several drugs can be used, each of them specifically targeted to the main component of discomfort to treat. In addition, analgosedation during NRS treatment should always be combined with close cardiorespiratory monitoring in an appropriate clinical setting.

CONCLUSIONS

The use of analgosedation during NRS has been studied in several clinical trials. However, its successful application relies on a thorough understanding of the pharmacological aspects of the sedative drugs used, the clinical conditions for which NRS is applied, and a careful selection of the appropriate clinical setting.

Incidence of noninvasive ventilation failure and mortality in patients with acute respiratory distress syndrome: a systematic review and proportion meta-analysis

BACKGROUND

Noninvasive ventilation (NIV) is commonly used in patients with acute respiratory distress syndrome (ARDS). However, the incidence and distribution of treatment failure are unclear.

METHODS

A comprehensive online search was conducted to select potentially eligible studies with reports of the rate of NIV failure in patients with ARDS. A manual search was also performed to identify additional studies. Data were extracted to calculate the pooled incidences of NIV failure and mortality. Based on oxygenation, the severity of the disease was classified as mild, moderate, or severe ARDS. Based on etiologies, ARDS was defined as being of pulmonary origin or extrapulmonary origin.

RESULTS

We enrolled 90 studies in this meta-analysis, involving 98 study arms. The pooled incidence of NIV failure was 48% (n = 5847, 95% confidence interval [CI]: 43-52%). The pooled incidence of ICU mortality was 29% (n = 2363, 95%CI: 22-36%), and that of hospital mortality was 33% (n = 2927, 95%CI: 27-40%). In patients with mild, moderate, and severe ARDS, the pooled incidence of NIV failure was 30% (n = 819, 95%CI: 21-39%), 51% (n = 1332, 95%CI: 43-60%), and 71% (n = 525, 95%CI: 62-79%), respectively. In patients with pulmonary ARDS, it was 45% (n = 2687, 95%CI: 39-51%). However, it was 30% (n = 802, 95%CI: 21-38%) in those with extrapulmonary ARDS. In patients with immunosuppression, the incidence of NIV failure was 62% (n = 806, 95%CI: 50-74%). However, it was 46% (n = 5041, 95%CI: 41-50%) in those without immunosuppression.

CONCLUSIONS

Nearly half of patients with ARDS experience NIV failure. The incidence of NIV failure increases with increasing ARDS severity. Pulmonary ARDS seems to have a higher rate of NIV failure than extrapulmonary ARDS. ARDS patients with immunosuppression have the highest rate of NIV failure.

Sepsis and acute respiratory failure in patients with cancer: how can we improve care and outcomes even further?

PURPOSE OF REVIEW

Care and outcomes of critically ill patients with cancer have improved over the past decade. This selective review will discuss recent updates in sepsis and acute respiratory failure among patients with cancer, with particular focus on important opportunities to improve outcomes further through attention to phenotyping, predictive analytics, and improved outcome measures.

RECENT FINDINGS

The prevalence of cancer diagnoses in intensive care units (ICUs) is nontrivial and increasing. Sepsis and acute respiratory failure remain the most common critical illness syndromes affecting these patients, although other complications are also frequent. Recent research in oncologic sepsis has described outcome variation - including ICU, hospital, and 28-day mortality - across different types of cancer (e.g., solid vs. hematologic malignancies) and different sepsis definitions (e.g., Sepsis-3 vs. prior definitions). Research in acute respiratory failure in oncology patients has highlighted continued uncertainty in the value of diagnostic bronchoscopy for some patients and in the optimal respiratory support strategy. For both of these syndromes, specific challenges include multifactorial heterogeneity (e.g. in etiology and/or underlying cancer), delayed recognition of clinical deterioration, and complex outcomes measurement.

SUMMARY

Improving outcomes in oncologic critical care requires attention to the heterogeneity of cancer diagnoses, timely recognition and management of critical illness, and defining appropriate ICU outcomes.

Cardiac arrest and complications during non-invasive ventilation: a systematic review and meta-analysis with meta-regression

PURPOSE

The aim of this study was to perform a systematic review and meta-analysis to investigate the incidence rate of cardiac arrest and severe complications occurring under non-invasive ventilation (NIV).

METHODS

We performed a systematic review and meta-analysis of studies between 1981 and 2020 that enrolled adults in whom NIV was used to treat acute respiratory failure (ARF). We generated the pooled incidence and confidence interval (95% CI) of NIV-related cardiac arrest per patient (primary outcome) and performed a meta-regression to assess the association with study characteristics. We also generated the pooled incidences of NIV failure and hospital mortality.

RESULTS

Three hundred and eight studies included a total of 7,601,148 participants with 36,326 patients under NIV (8187 in 138 randomized controlled trials, 9783 in 99 prospective observational studies, and 18,356 in 71 retrospective studies). Only 19 (6%) of the analyzed studies reported the rate of NIV-related cardiac arrest. Forty-nine cardiac arrests were reported. The pooled incidence was 0.01% (95% CI 0.00-0.02, I² = 0% (0-15)). NIV failure was reported in 4371 patients, with a pooled incidence of 11.1% (95% CI 9.0-13.3). After meta-regression, NIV failure and the study period (before 2010) were significantly associated with NIV-related cardiac arrest. The hospital mortality pooled incidence was 6.0% (95% CI 4.4-7.9).

CONCLUSION

Cardiac arrest related to NIV occurred in one per 10,000 patients under NIV for ARF treatment. NIV-related cardiac arrest was associated with NIV failure.

High-flow nasal cannula failure in critically ill cancer patients with acute respiratory failure: Moving from avoiding intubation to avoiding delayed intubation

Background

High-flow nasal cannula (HFNC) is increasingly used in critically ill cancer patients with acute respiratory failure (ARF) to avoid mechanical ventilation (MV). The objective was to assess prognostic factors associated with mortality in ICU cancer patients requiring MV after HFNC failure, and to identify predictive factors of intubation.

Methods

We conducted a retrospective study from 2012–2016 in a cancer referral center. All consecutive onco-hematology adult patients admitted to the ICU treated with HFNC were included. HFNC failure was defined by intubation requirement.

Results

202 patients were included, 104 successfully treated with HFNC and 98 requiring intubation. ICU and hospital mortality rates were 26.2% (n = 53) and 42.1% (n = 85) respectively, and 53.1% (n = 52) and 68.4% (n = 67) in patients requiring MV. Multivariate analysis identified 4 prognostic factors of hospital mortality after HFNC failure: complete/partial remission (OR = 0.2, 95%CI = 0.04–0.98, p<0.001) compared to patients with refractory/relapse disease (OR = 3.73, 95%CI = 1.08–12.86), intubation after day 3 (OR = 7.78, 95%CI = 1.44–41.96), number of pulmonary quadrants involved on chest X-ray (OR = 1.93, 95%CI = 1.14–3.26, p = 0.01) and SAPSII at ICU admission (OR = 1.06, 95%CI = 1–1.12, p = 0.019). Predictive factors of intubation were the absence of sepsis (sHR = 0.32, 95%CI = 0.12–0.74, p = 0.0087), Sp02<95% 15 minutes after HFNC initiation (sHR = 2.05, 95%CI = 1.32–3.18, p = 0.0014), number of quadrants on X-ray (sHR = 1.73, 95%CI = 1.46–2.06, p<0.001), Fi02>60% at HFNC initiation (sHR = 3.12, 95%CI = 2.06–4.74, p<0.001) and SAPSII at ICU admission (sHR = 1.03, 95%CI = 1.02–1.05, p<0.01).

Conclusion

Duration of HFNC may be predictive of an excess mortality in ARF cancer patients. Early warning scores to predict HFNC failure are needed to identify patients who would benefit from early intubation.

High Flow Nasal Cannula as Support in Immunocompromised Patients with Acute Respiratory Failure: A Retrospective Study

Introduction:

High Flow Nasal Cannula (HFNC) is a novel technique for respiratory support that improves oxygenation. In some patients, it may reduce the work of breathing. In immunocompromised patients with Acute Respiratory Failure (ARF), Non-Invasive Ventilation (NIV) is the main support recommended strategy, since invasive mechanical ventilation could increase mortality rates. NIV used for more than 48 hours may be associated with increased in-hospital mortality and hospital length of stay. Therefore HFNC seems like a respiratory support alternative.

Objective:

To describe clinical outcomes of immunocompromised patients with ARF HFNC-supported.

Methods:

Retrospective study in patients admitted with ARF and HFNC-supported. 25 adult patients were included, 21 pharmacologically and 4 non- pharmacologically immunosuppressed. Median age of the patients was 64 [60-76] years, APACHE II 15 [11-19], and PaO2:FiO2 218 [165-248]. Demographic information, origin of immunosuppression, Respiratory Rate (RR), Heart Rate (HR), Mean Arterial Pressure (MAP), oxygen saturation (SpO2) and PaO2:FiO2 ratio were extracted from clinical records of our HFNC local protocol. Data acquisition was performed before and after the first 24 hours of connection. In addition, the need for greater ventilatory support after HFNC, orotracheal intubation, in-hospital mortality and 90 days out-patients’ mortality was recorded.

Results:

Mean RR before the connection was 25±22 breaths/min and 22±4 breaths/min after the first 24 hours of HFNC use (95% CI; p=0.02). HR mean before connection to HFNC was 96±22 beats/min, and after, it was 86±15 beats/min (95%CI; p=0.008). Previous mean MAP was 86±15 mmHg, and after HFNC, it was 80±12 mmHg (95%CI; p=0.09); mean SpO2 after was 93±5% and before it was 95±4% (95% CI; p=0.13); and previous PaO2:FiO2 mean was 219±66, and after it was 324±110 (95%CI; p=0.52). In-hospital mortality was 28% and 90 days out-patients’ mortality was 32%.

Conclusion:

HFNC in immunosuppressed ARF subjects significantly decreases HR and RR, being apparently an effective alternative to decrease work of breathing. In-hospital mortality in ARF immunosuppressed patients was high even though respiratory support was used. Better studies are needed to define the role of HFNC-support in ARF.

Oxygenation strategy during acute respiratory failure in immunocompromised patients

Acute respiratory failure (ARF) in immunocompromised patients remains challenging to treat. A large number of case require admission to intensive care unit (ICU) where mortality remains high. Oxygenation without intubation is important in this setting. This review summarizes recent studies assessing oxygenation devices for immunocompromised patients. Previous studies showed that non-invasive ventilation (NIV) has been associated with lower intubation and mortality rates. Indeed, in recent years, the outcomes of immunocompromised patients admitted to the ICU have improved. In the most recent randomized controlled trials, including immunocompromised patients admitted to the ICU with ARF, neither NIV nor high-flow nasal oxygen (HFNO) could reduce the mortality rate. In this setting, other strategies need to be tested to decrease the mortality rate. Early admission strategy and avoiding late failure of oxygenation strategy have been assessed in retrospective studies. However, objective criteria are still lacking to clearly discriminate time to admission or time to intubation. Also, diagnosis strategy may have an impact on intubation or mortality rates. On the other hand, lack of diagnosis has been associated with a higher mortality rate. In conclusion, improving outcomes in immunocompromised patients with ARF may include strategies other than the oxygenation strategy alone. This review discusses other unresolved questions to decrease mortality after ICU admission in such patients.

Oxygenation Strategy During Acute Respiratory Failure in Critically-Ill Immunocompromised Patients

OBJECTIVES

To assess the response to initial oxygenation strategy according to clinical variables available at admission.

DESIGN

Multicenter cohort study.

SETTING

Thirty French and Belgium medical ICU.

SUBJECTS

Immunocompromised patients with hypoxemic acute respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were extracted from the Groupe de Recherche en Reanimation Respiratoire du patient d'Onco-Hématologie database. Need for invasive mechanical ventilation was the primary endpoint. Secondary endpoint was day-28 mortality. Six-hundred forty-nine patients were included. First oxygenation strategies included standard oxygen (n = 245, 38%), noninvasive ventilation (n = 285; 44%), high-flow nasal cannula oxygen (n = 55; 8%), and noninvasive ventilation + high-flow nasal cannula oxygen (n = 64; 10%). Bilateral alveolar pattern (odds ratio = 1.67 [1.03-2.69]; p = 0.04), bacterial (odds ratio = 1.98 [1.07-3.65]; p = 0.03) or opportunistic infection (odds ratio = 4.75 [2.23-10.1]; p < 0.001), noninvasive ventilation use (odds ratio = 2.85 [1.73-4.70]; p < 0.001), Sequential Organ Failure Assessment score (odds ratio = 1.19 [1.10-1.28]; p < 0.001), and ratio of PaO2 and FIO2 less than 100 at ICU admission (odds ratio = 1.96 [1.27-3.02]; p = 0.0002) were independently associated with intubation rate. Day-28 mortality was independently associated with bacterial (odds ratio = 2.34 [1.10-4.97]; p = 0.03) or opportunistic infection (odds ratio = 4.96 [2.11-11.6]; p < 0.001), noninvasive ventilation use (odds ratio = 2.35 [1.35-4.09]; p = 0.003), Sequential Organ Failure Assessment score (odds ratio = 1.19 [1.10-1.28]; p < 0.001), and ratio of PaO2 and FIO2 less than 100 at ICU admission (odds ratio = 1.97 [1.26-3.09]; p = 0.003). High-flow nasal cannula oxygen use was neither associated with intubation nor mortality rates.

CONCLUSIONS

Some clinical characteristics at ICU admission including etiology and severity of acute respiratory failure enable to identify patients at high risk for intubation.

The Effect of Immunosuppression on Emergency Colectomy Outcomes: A Nationwide Retrospective Analysis

BACKGROUND

The impact of immunosuppression on the outcomes of emergent surgery remains poorly described. We aimed to quantify the impact of chronic immunosuppression on outcomes of patients undergoing emergent colectomy (EC).

METHODS

The Colectomy-Targeted ACS-NSQIP database 2012-2016 was queried for patients who underwent colectomy for an emergent indication. As per NSQIP, chronic immunosuppression was defined as the use of corticosteroid or immunosuppressant medication within the prior 30 days. Patients undergoing EC for any indication were divided into two groups: immunosuppressant use (IMS) and no immunosuppressant use (NIS). Patients were propensity-score-matched on demographics, comorbidities, preoperative laboratory values, and operative variables in a 1:1 ratio to control for confounding factors. The primary outcome was 30-day mortality. Secondary outcomes included overall 30-day morbidity, individual postoperative complications (e.g., wound dehiscence, anastomotic leak, and sepsis), and hospital length of stay.

RESULTS

Out of a total of 130,963 patients, 17,707 patients underwent an EC, of which 15,422 were NIS and 2285 were IMS. Totally, 2882 patients were matched (1441 NIS; 1441 IMS). The median age was 66 [IQR 56-76]; 56.8% were female; patients more frequently underwent a diversion procedure rather than primary anastomosis (68.4% vs 31.6%). Overall, as compared to NIS, IMS patients had higher 30-day mortality (21.4% vs 18.5%, p = 0.045) and overall morbidity (79.7% vs 75.7%, p = 0.011). Particularly, IMS patients had increased rates of unplanned intubations (11.5% vs 7.9%, p = 0.001), wound dehiscence (5.7% vs 3.5%, p = 0.006), progressive renal insufficiency 2.2% vs 1.2%, p = 0.042), pneumonia (12.6% vs 10.0%, p = 0.029), and longer median hospital length of stay [12.0 (8.0-21.0) vs 11.0 (7.0-19.0), p < 0.001] as compared to NIS patients.

CONCLUSIONS

Chronic immunosuppression is independently associated with a significant and quantifiable increase in 30-day mortality and complications for patients undergoing EC. Our results provide the emergency surgeon with quantifiable risk estimates that can help guide better patient counseling while setting reasonable expectations.

Association of Noninvasive Oxygenation Strategies With All-Cause Mortality in Adults With Acute Hypoxemic Respiratory Failure: A Systematic Review and Meta-analysis

IMPORTANCE

Treatment with noninvasive oxygenation strategies such as noninvasive ventilation and high-flow nasal oxygen may be more effective than standard oxygen therapy alone in patients with acute hypoxemic respiratory failure.

OBJECTIVE

To compare the association of noninvasive oxygenation strategies with mortality and endotracheal intubation in adults with acute hypoxemic respiratory failure.

DATA SOURCES

The following bibliographic databases were searched from inception until April 2020: MEDLINE, Embase, PubMed, Cochrane Central Register of Controlled Trials, CINAHL, Web of Science, and LILACS. No limits were applied to language, publication year, sex, or race.

STUDY SELECTION

Randomized clinical trials enrolling adult participants with acute hypoxemic respiratory failure comparing high-flow nasal oxygen, face mask noninvasive ventilation, helmet noninvasive ventilation, or standard oxygen therapy.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted individual study data and evaluated studies for risk of bias using the Cochrane Risk of Bias tool. Network meta-analyses using a bayesian framework to derive risk ratios (RRs) and risk differences along with 95% credible intervals (CrIs) were conducted. GRADE methodology was used to rate the certainty in findings.

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause mortality up to 90 days. A secondary outcome was endotracheal intubation up to 30 days.

RESULTS

Twenty-five randomized clinical trials (3804 participants) were included. Compared with standard oxygen, treatment with helmet noninvasive ventilation (RR, 0.40 [95% CrI, 0.24-0.63]; absolute risk difference, -0.19 [95% CrI, -0.37 to -0.09]; low certainty) and face mask noninvasive ventilation (RR, 0.83 [95% CrI, 0.68-0.99]; absolute risk difference, -0.06 [95% CrI, -0.15 to -0.01]; moderate certainty) were associated with a lower risk of mortality (21 studies [3370 patients]). Helmet noninvasive ventilation (RR, 0.26 [95% CrI, 0.14-0.46]; absolute risk difference, -0.32 [95% CrI, -0.60 to -0.16]; low certainty), face mask noninvasive ventilation (RR, 0.76 [95% CrI, 0.62-0.90]; absolute risk difference, -0.12 [95% CrI, -0.25 to -0.05]; moderate certainty) and high-flow nasal oxygen (RR, 0.76 [95% CrI, 0.55-0.99]; absolute risk difference, -0.11 [95% CrI, -0.27 to -0.01]; moderate certainty) were associated with lower risk of endotracheal intubation (25 studies [3804 patients]). The risk of bias due to lack of blinding for intubation was deemed high.

CONCLUSIONS AND RELEVANCE

In this network meta-analysis of trials of adult patients with acute hypoxemic respiratory failure, treatment with noninvasive oxygenation strategies compared with standard oxygen therapy was associated with lower risk of death. Further research is needed to better understand the relative benefits of each strategy.

Noninvasive oxygenation strategies in adult patients with acute respiratory failure: a protocol for a systematic review and network meta-analysis

BACKGROUND

Acute hypoxemic respiratory failure is one of the leading causes of intensive care unit admission and is associated with high mortality. Noninvasive oxygenation strategies such as high-flow nasal cannula, standard oxygen therapy, and noninvasive ventilation (delivered by either face mask or helmet interface) are widely available interventions applied in these patients. It remains unclear which of these interventions are more effective in decreasing rates of invasive mechanical ventilation and mortality. The primary objective of this network meta-analysis is to summarize the evidence and compare the effect of noninvasive oxygenation strategies on mortality and need for invasive mechanical ventilation in patients with acute hypoxemic respiratory failure.

METHODS

We will search key databases for randomized controlled trials assessing the effect of noninvasive oxygenation strategies in adult patients with acute hypoxemic respiratory failure. We will exclude studies in which the primary focus is either acute exacerbations of chronic obstructive pulmonary disease or cardiogenic pulmonary edema. The primary outcome will be all-cause mortality (longest available up to 90 days). The secondary outcomes will be receipt of invasive mechanical ventilation (longest available up to 30 days). We will assess the risk of bias for each of the outcomes using the Cochrane Risk of Bias Tool. Bayesian network meta-analyses will be conducted to obtain pooled estimates of head-to-head comparisons. We will report pairwise and network meta-analysis treatment effect estimates as risk ratios and 95% credible intervals. Subgroup analyses will be conducted examining key populations including immunocompromised hosts. Sensitivity analyses will be conducted by excluding those studies with high risk of bias and different etiologies of acute respiratory failure. We will assess certainty in effect estimates using GRADE methodology.

DISCUSSION

This study will help to guide clinical decision-making when caring for adult patients with acute hypoxemic respiratory failure and improve our understanding of the limitations of the available literature assessing noninvasive oxygenation strategies in acute hypoxemic respiratory failure.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019121755.

Use of High-Flow Nasal Cannula for Immunocompromise and Acute Respiratory Failure: A Systematic Review and Meta-Analysis

BACKGROUND

Acute respiratory failure (ARF) is a common cause of emergency department (ED) and intensive care unit (ICU) admissions. High-flow nasal cannula oxygen therapy (HFNC) is widely used for patients with ARF.

OBJECTIVE

Our aim was to evaluate the latest evidence regarding the application of HFNC in immunocompromised patients with ARF.

METHODS

We searched PubMed, Embase, and Cochrane databases from inception to January 2019. The primary outcome was short-term mortality and the secondary outcomes were intubation rate and length of ICU stay.

RESULTS

Eight studies involving 2,179 immunocompromised subjects with ARF were included. No significant differences for short-term mortality were observed when comparing HFNC with conventional oxygen therapy (COT) (risk ratio [RR] 0.89; 95% confidence interval [CI] 0.73 to 1.09; p = 0.25, I² = 47%) and with noninvasive ventilation (NIV) (RR 0.66; 95% CI 0.37 to 1.18; p = 0.16, I² = 58%). Lower intubation rates were found when comparing HFNC with COT (RR 0.89; 95% CI 0.80 to 0.99; p = 0.03, I² = 0%) and no significant difference was found between HFNC and NIV (RR 0.74; 95% CI 0.46 to 1.19; p = 0.22, I² = 67%). The length of ICU stay was similar when comparing HFNC with COT (mean difference [MD] 0.59; 95% CI -1.68 to 2.85; p = 0.61, I² = 56%), but was significantly shorter when HFNC was compared with NIV (MD -2.13; 95% CI -3.98 to -0.29; p = 0.02, I² = 0%).

CONCLUSIONS

There was no significant difference in short-term mortality with use of HFNC when compared with COT or NIV for immunocompromised patients with ARF. A lower intubation rate than COT and a shorter length of ICU stay than NIV were observed in the HFNC group.

Causes of acute respiratory failure in the immunocompromised host

PURPOSE OF REVIEW

A wide spectrum of heterogeneous conditions can render a patient immunocompromised. Recent years have seen an increase in the number of immunocompromised patients given the earlier detection of conditions that require immunosuppressive therapies, changes in immunosuppressive regimens leading to increased survival or novel therapeutic advancements in oncologic care. Acute respiratory failure (ARF) is the leading cause of critical illness and mortality in this population. This review highlights the spectrum of causes of ARF in immunocompromised patients with a particular focus on acute toxicities of novel oncologic treatments.

RECENT FINDINGS

Recent years have seen improved survival amongst critically ill immunocompromised patients with ARF. This is likely attributable to patient selection of immunosuppressive therapy, improved noninvasive microbiologic diagnostic techniques, improved antimicrobial prophylaxis, treatment, stewardship, and advancements in supportive care including intensive care. Infectious complications remain the leading cause of ARF in this population. However, one of the greatest challenges physicians continue to face is accurate identification of the cause of ARF, given the vast (and increasing) noninfectious causes of ARF across these patients. Emerging therapies, such as immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell therapy (CAR T-cell) have contributed to this problem. Finally, undetermined ARF is reported in approximately 13% of immunocompromised and is associated with a worse prognosis.

SUMMARY

Infectious complications are still the leading cause of ARF in immunocompromised patients. However, noninfectious complications, derived from the underlying disease or treatment, should be always considered, including novel therapies, such as ICIs and CAR T cells. Further research should focus in improving the diagnostic rate in this subgroup.

Outcomes of hematopoietic cell transplant recipients requiring invasive mechanical ventilation: a two-centre retrospective cohort study

PURPOSE

Outcomes of critically ill, hematopoietic cell transplant patients who require prolonged mechanical ventilation are not well studied. We describe the baseline characteristics, critical care management, and outcomes of this population and explore potential predictors of mortality.

METHODS

We performed a retrospective cohort study in two critical care units in Ontario. We included adult intensive care unit patients who required invasive mechanical ventilation within 90 days of receiving a hematopoietic cell transplant. The primary outcome was mortality at 90 days. Using logistic regression, we explored predictors of mortality including type of transplant (allogeneic vs autologous), severity of illness (assessed using the Sequential Organ Failure Assessment [SOFA] score), and baseline characteristics (such as age and sex).

RESULTS

We included 70 patients from two study sites. Ninety-day mortality was 73% (n = 51) in the entire cohort, 58% (15/26) in patients post-autologous transplant, and 82% (36/44) in those post-allogeneic transplant. Ninety-one percent (10/11) of patients who required invasive mechanical ventilation for more than 21 days died. Independent predictors of all-cause mortality included allogeneic transplant, higher SOFA score, the presence of acute hypoxemic respiratory failure, and a longer interval between receiving the transplant and initiation of mechanical ventilation.

CONCLUSIONS

Our study shows high rates of mortality among hematopoietic cell transplant recipients that require invasive mechanical ventilation, particularly in those post-allogeneic transplant and in those who require prolonged ventilation for more than 21 days.