Immunocompromised patients with acute respiratory distress syndrome: secondary analysis of the LUNG SAFE database

ICU Complications of Hematopoietic Stem Cell Transplant, Including Graft vs Host Disease

Hematopoietic stem cell transplant (HSCT) is an essential treatment modality for many malignant and non-malignant hematologic diseases. Advances in HSCT techniques have dramatically decreased peri-transplant morbidity and mortality, but it remains a high-risk procedure, and a significant number of patients will require critical care during the transplant process. Complications of HSCT are both infectious and non-infectious, and the intensivist must be familiar with common infections, the management of neutropenic sepsis and septic shock, the management of respiratory failure in the immunocompromised host, and a plethora of HSCT-specific complications. Survival from critical illness after HSCT is improving, but the mortality rate remains unacceptably high. Continued research and optimization of critical care provision in this population should continue to improve outcomes.

Noninvasive Oxygen Therapies in Oncologic Patients

Acute hypoxemic respiratory failure (ARF) is the most common cause of critical illness in oncologic patients. Despite significant advancements in survival of oncologic patients who develop critical illness, mortality rates in those requiring invasive mechanical ventilation have improved but remain high. Avoiding intubation is paramount to the management of oncologic patients with ARF. There are important differences between the oncologic patient with ARF compared to the general ICU population that likely underlie the increased mortality once intubated. Noninvasive oxygen modalities have been recognized as an important therapeutic approach to prevent intubation. Continuous low-flow oxygen therapy, noninvasive ventilation, and high-flow nasal cannula are the most commonly used noninvasive oxygen therapies in recent years. They have unique physiologic properties. The data surrounding their efficacy in the general ICU population and oncologic population has evolved over time reflecting the changes in the oncologic population. This chapter reviews the three different noninvasive oxygen modalities, their physiologic impact, and evidence surrounding their effectiveness.

RNAi therapeutic strategies for acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS), replacing the clinical term acute lung injury, involves serious pathophysiological lung changes that arise from a variety of pulmonary and nonpulmonary injuries and currently has no pharmacological therapeutics. RNA interference (RNAi) has the potential to generate therapeutic effects that would increase patient survival rates from this condition. It is the purpose of this review to discuss potential targets in treating ARDS with RNAi strategies, as well as to outline the challenges of oligonucleotide delivery to the lung and tactics to circumvent these delivery barriers.

Tidal Volume Estimation during Helmet Noninvasive Ventilation: an Experimental Feasibility Study

We performed a bench (BS) and human (HS) study to test the hypothesis that estimation of tidal volume (V_T) during noninvasive helmet pressure support ventilation (nHPSV) would be possible using a turbine driven ventilator (TDV) coupled with an intentional leak single-limb vented circuit. During the BS a mannequin was connected to a lung simulator (LS) and at different conditions of respiratory mechanics, positive end expiratory pressure (PEEP) levels and leaks (30, 50 and 80 L/min). All differences were within the 95% limits of agreement (LoA) in all conditions in the Bland-Altman plot. The overall bias (difference between V_T measured by TDV and LS) was 35 ml (95% LoA 10 to 57 ml), 15 ml (95% LoA −40 to 70 ml), 141 ml (95% LoA 109 to 173 ml) in the normal, restrictive and obstructive conditions. The bias at different leaks flow in normal condition was 29 ml (95% LoA 19 to 38 ml). In the HS four healthy volunteers using nHPSV had a pneumotachograph (P) inserted through a mouthpiece to measure subject’s V_T.The bias showed a scarce clinical relevance. In conclusions, V_T estimation seems to be feasible and accurate in all conditions but the obstructive one. Additional leaks seem not to affect V_T reliability.

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.

High-flow nasal oxygen therapy alone or with non-invasive ventilation in immunocompromised patients admitted to ICU for acute hypoxemic respiratory failure: the randomised multicentre controlled FLORALI-IM protocol

INTRODUCTION

Non-invasive ventilation (NIV) is recommended as first-line therapy in respiratory failure of critically ill immunocompromised patients as it can decrease intubation and mortality rates as compared with standard oxygen. However, its recommendation is only conditional. Indeed, the use of NIV in this setting has been challenged recently based on results of trials finding similar outcomes with or without NIV or even deleterious effects of NIV. To date, NIV has been compared with standard oxygen but not to high-flow nasal oxygen therapy (HFOT) in immunocompromised patients. Several studies have found lower mortality rates using HFOT alone than when using HFOT with NIV sessions in patients with de novo respiratory failure, and even in immunocompromised patients. We are hypothesising that HFOT alone is more effective than HFOT with NIV sessions and reduces mortality of immunocompromised patients with acute hypoxemic respiratory failure.

METHODS AND ANALYSIS

This study is an investigator-initiated, multicentre randomised controlled trial comparing HFOT alone or with NIV in immunocompromised patients admitted to intensive care unit (ICU) for severe acute hypoxemic respiratory failure. Around 280 patients will be randomised with a 1:1 ratio in two groups. The primary outcome is the mortality rate at day 28 after inclusion. Secondary outcomes include the rate of intubation in each group, length of ICU and hospital stay and mortality up to day 180.

ETHICS AND DISSEMINATION

The study has been approved by the ethics committee and patients will be included after informed consent. The results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02978300.

High-flow nasal therapy versus noninvasive ventilation in COPD patients with mild-to-moderate hypercapnic acute respiratory failure: study protocol for a noninferiority randomized clinical trial

Background

Noninvasive ventilation (NIV) is indicated to treat respiratory acidosis due to exacerbation of chronic obstructive pulmonary disease (COPD). Recent nonrandomized studies also demonstrated some physiological effects of high-flow nasal therapy (HFNT) in COPD patients. We designed a prospective, unblinded, multicenter, randomized controlled trial to assess the noninferiority of HFNT compared to NIV with respect to the reduction of arterial partial pressure of carbon dioxide (PaCO₂) in patients with hypercapnic acute respiratory failure with mild-to-moderate respiratory acidosis.

Methods

We will enroll adult patients with acute hypercapnic respiratory failure, as defined by arterial pH between 7.25 and 7.35 and PaCO₂ ≥ 55 mmHg. Patients will be randomly assigned 1:1 to receive NIV or HFNT. NIV will be applied through a mask with a dedicated ventilator in pressure support mode. Positive end-expiratory pressure will be set at 3–5 cmH₂O with inspiratory support to obtain a tidal volume between 6 and 8 ml/kg of ideal body weight. HFNT will be initially set at a temperature of 37 °C and a flow of 60 L/min. At 2 and 6 h we will assess arterial blood gases, vital parameters, respiratory rate, treatment intolerance and failure, need for endotracheal intubation, time spent under mechanical ventilation (both invasive and NIV), intensive care unit and hospital length of stay, and hospital mortality.

Based on an α error of 5% and a β error of 80%, with a standard deviation for PaCO₂ equal to 15 mmHg and a noninferiority limit of 10 mmHg, we computed a sample size of 56 patients. Considering potential drop-outs and nonparametric analysis, the final computed sample size was 80 patients (40 per group).

Discussion

HFNT is more comfortable than NIV in COPD patients recovering from an episode of exacerbation. If HFNT would not be inferior to NIV, HFNT could be considered as an alternative to NIV to treat COPD patients with mild-to-moderate respiratory acidosis.

Trial registration

ClinicalTrials.gov, NCT03370666. Registered on December 12, 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3514-1) contains supplementary material, which is available to authorized users.

Noninvasive Oxygenation Strategies in Immunocompromised Patients With Acute Hypoxemic Respiratory Failure: A Pairwise and Network Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

Acute hypoxemic respiratory failure (AHRF) is a leading cause of intensive care unit (ICU) admission among immunocompromised patients. Invasive mechanical ventilation is associated with increased morbidity and mortality.

OBJECTIVE

To evaluate the efficacy of various oxygenation strategies including noninvasive ventilation (NIV), high-flow nasal cannula (HFNC), and conventional oxygen therapy in immunocompromised patients with AHRF.

METHODS

Electronic databases including PubMed, Embase, and the Cochrane Library were reviewed from inception to December 2018. We included all randomized controlled trials (RCTs) comparing different modalities of initial oxygenation strategies in immunocompromised patients with AHRF. Our primary outcome was the need for intubation and invasive mechanical ventilation while secondary outcomes were ICU acquired infections and short- and long-term mortality. Data were extracted separately and independently by 2 reviewers. We performed a Bayesian network meta-analysis to calculate odds ratio (OR) and Bayesian 95% credible intervals (CrIs).

RESULTS

Nine RCTs were included (1570 patients, mean age 61.1 ± 13.8 years with 64% male). Noninvasive ventilation was associated with a significantly reduced intubation rate compared with standard oxygen therapy (OR: 0.53; 95% CrI: 0.26-0.91). There were no significant reductions of intubation between NIV versus HFNC (OR: 0.83; 95% CrI: 0.35-2.11) or HFNC versus standard oxygen therapy (OR: 0.65; 95% CrI: 0.26-1.24). There were no significant differences between all groups regarding short-term (28-day or ICU) mortality or long-term (90-day or hospital) mortality or ICU-acquired infections (P > 0.05).

CONCLUSION

Among immunocompromised patients with AHRF, NIV was associated with a significant reduction of intubation compared with standard oxygen therapy. There were no significant differences among all oxygenation strategies regarding mortality and ICU-acquired infections.

Acute Respiratory Failure in the Oncologic Patient: New Era, New Issues

Recent decades have seen an increase in the number of patients living with cancer. This trend has resulted in an increase in intensive care unit (ICU) utilization across this population [1]. Acute respiratory failure is the most frequent medical complication leading to critical illness in oncologic patients [2–4]. Historically, there had been a reluctance to admit cancer patients to the ICU given their poor outcomes, particularly in the setting of hematologic malignancy and invasive mechanical ventilation [5]. ICU treatment limitations or refusal of admission was advocated [6]. Major advances in oncologic care, critical care and more meticulous attention to where the conditions overlap, have resulted in marked improvement in short-term survival in this population [1, 7, 8]. Despite these major advances, acute respiratory failure in this population remains complex with unique challenges surrounding diagnosis and management compared to the general ICU population. This chapter provides a comprehensive overview of acute respiratory failure in the oncologic population and highlights specific considerations for the intensivist. We will focus on the important differences between the immunocompromised oncologic patient and general intensive care population, the spectrum of causes of acute respiratory failure with a specific focus on toxicities related to newer cancer therapies, diagnostic approach, management and an up-to-date overview of prognosis.

Acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is a common cause of respiratory failure in critically ill patients and is defined by the acute onset of noncardiogenic pulmonary oedema, hypoxaemia and the need for mechanical ventilation. ARDS occurs most often in the setting of pneumonia, sepsis, aspiration of gastric contents or severe trauma and is present in ~10% of all patients in intensive care units worldwide. Despite some improvements, mortality remains high at 30-40% in most studies. Pathological specimens from patients with ARDS frequently reveal diffuse alveolar damage, and laboratory studies have demonstrated both alveolar epithelial and lung endothelial injury, resulting in accumulation of protein-rich inflammatory oedematous fluid in the alveolar space. Diagnosis is based on consensus syndromic criteria, with modifications for under-resourced settings and in paediatric patients. Treatment focuses on lung-protective ventilation; no specific pharmacotherapies have been identified. Long-term outcomes of patients with ARDS are increasingly recognized as important research targets, as many patients survive ARDS only to have ongoing functional and/or psychological sequelae. Future directions include efforts to facilitate earlier recognition of ARDS, identifying responsive subsets of patients and ongoing efforts to understand fundamental mechanisms of lung injury to design specific treatments.

High flow nasal therapy in immunocompromised patients with acute respiratory failure: A systematic review and meta-analysis

PURPOSE

The role of high-flow nasal therapy (HFNT) as compared to conventional oxygen therapy (COT) in immunocompromised patients admitted to intensive care unit (ICU) with acute respiratory failure (ARF) remains unclear. We conducted a systematic review and meta-analysis in order to address this issue.

METHODS

We searched PubMed, Medline and Embase until November 7th, 2018. Randomized controlled trials (RCTs), non-randomized prospective and retrospective evidence were selected. Observational studies were considered for sensitivity analysis. Primary outcome was mortality rate; intubation rate was a secondary outcome.

RESULTS

We included four studies in the primary analysis: one RCT, two RCT's post-hoc analyses and one retrospective study. We found no significant difference in short-term mortality comparing HFNT vs. COT: 1) ICU: n = 872 patients, odds ratio (OR) = 0.80 [0.44,1.45], p = 0.46, I² = 30%, p = 0.24; 2) 28-day: n = 996 patients, OR = 0.79 [0.45,1.38], p = 0.40, I² = 52%, p = 0.12). Conversely, we found a reduction of intubation rate in the HFNT group (n = 1052 patients, OR = 0.74 [0.55,0.98], p = 0.03, I² = 7%, p = 0.36). The inclusion of one observational study for sensitivity analysis did not grossly change results.

CONCLUSIONS

We found no benefit of HFNT over COT on mortality in immunocompromised patients with ARF. However, HFNT was associated with a lower intubation rate warranting further research.

Prise en charge du transplanté rénal en réanimation

La transplantation rénale est la thérapeutique de choix de l’insuffisance rénale chronique au stade ultime, son usage est de plus en plus large. Les progrès réalisés dans les traitements immunosuppresseurs ont permis une amélioration de la durée de vie du greffon, mais au prix d’une augmentation des complications cardiovasculaires et infectieuses. Environ 5 % des transplantés rénaux présentent des complications sévères qui nécessitent une prise en charge intensive. Elles sont principalement de cause infectieuse et dominées par la défaillance respiratoire aiguë. L’insuffisance rénale aiguë est commune, elle affecte la fonction du greffon à court et long termes. La prise en charge en réanimation de ces complications doit prendre en compte le terrain particulier du transplanté rénal et les effets délétères de l’immunosuppression, condition nécessaire à une amélioration de la mortalité qui reste à plus de 30 %.