Single-Center Experience With Venovenous ECMO for Influenza-Related ARDS

Outcomes following additional drainage during veno-venous extracorporeal membrane oxygenation: A single-center retrospective study

Refractory hypoxemia during veno-venous (V-V) extracorporeal membrane oxygenation (ECMO) may require an additional cannula (VV-V ECMO) to improve oxygenation. This intervention includes risk of recirculation and other various adverse events (AEs) such as injury to the lung, cannula malpositioning, bleeding, circuit or cannula thrombosis requiring intervention (i.e., clot), or cerebral injury. During the study period, 23 of 142 V-V ECMO patients were converted to VV-V utilizing two separate cannulas for bi-caval drainage with an additional upper extremity cannula placed for return. Of those, 21 had COVID-19. In the first 24 h after conversion, ECMO flow rates were higher (5.96 vs 5.24 L/min, p = .002) with no significant change in pump speed (3764 vs 3630 revolutions per minute [RPMs], p = .42). Arterial oxygenation (PaO2) increased (87 vs 64 mmHg, p < .0001) with comparable pre-oxygenator venous saturation (61 vs 53.3, p = .12). By day 5, flows were similar to pre-conversion values at lower pump speed but with improved PaO2. Unadjusted survival was similar in those converted to VV-V ECMO compared to V-V ECMO alone (70% [16/23] vs 66.4% [79/119], p = .77). In a mixed effect regression model, any incidence of AEs, demonstrated a negative impact on PaO2 in the first 48 h but not at day 5. VV-V ECMO improved oxygenation with increasing flows without a significant difference in AEs or pump speed. AEs transiently impacted oxygenation. VV-V ECMO is effective and feasible strategy for refractory hypoxemia on VV-ECMO allowing for higher flow rate and unchanged pump speed.

CT findings of 144 in-hospital patients with influenza pneumonia: A retrospective analysis

BACKGROUND/PURPOSE

Patients with influenza infection during their period of admission may have worse computed tomography (CT) manifestation according to the clinical status. This study aimed to evaluate the CT findings of in-hospital patients due to clinically significant influenza pneumonia with correlation of clinical presentations.

METHODS

In this retrospective, single center case series, 144 patients were included. All in-hospital patients were confirmed influenza infection and underwent CT scan. These patients were divided into three groups according to the clinical status of the most significant management: (1) without endotracheal tube and mechanical ventilator (ETTMV) or extracorporeal membrane oxygenation (ECMO); (2) with ETTMV; (3) with ETTMV and ECMO. Pulmonary opacities were scored according to extent. Spearman rank correlation analysis was used to evaluate the correlation between clinical parameters and CT scores.

RESULTS

The predominant CT manifestation of influenza infection was mixed ground-glass opacity (GGO) and consolidation with both lung involvement. The CT scores were all reach significant difference among all three groups (8.73 ± 6.29 vs 12.49 ± 6.69 vs 18.94 ± 4.57, p < 0.05). The chest CT score was correlated with age, mortality, and intensive care unit (ICU) days (all p values were less than 0.05). In addition, the CT score was correlated with peak lactate dehydrogenase (LDH) level and peak C-reactive protein (CRP) level (all p values were less than 0.05). Concomitant bacterial infection had higher CT score than primary influenza pneumonia (13.02 ± 7.27 vs 8.95 ± 5.99, p < 0.05).

CONCLUSION

Thin-section chest CT scores correlated with clinical and laboratory parameters in in-hospital patients with influenza pneumonia.

COVID-19 outcomes of venovenous extracorporeal membrane oxygenation for acute respiratory failure vs historical cohort of non-COVID-19 viral infections

INTRODUCTION

Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become a support modality for patients with acute respiratory failure refractory to standard therapies. VV ECMO has been increasingly used during the current COVID-19 pandemic for patients with refractory respiratory failure. The object of this study was to evaluate the outcomes of VV ECMO in patients with COVID-19 compared to patients with non-COVID-19 viral infections.

METHODS

We retrospectively reviewed all patients supported with VV ECMO between 8/2014 and 8/2020 whose etiology of illness was a viral pulmonary infection. The primary outcome of this study was to evaluate in-hospital mortality. The secondary outcomes included length of ECMO course, ventilator duration, hospital length of stay, incidence of adverse events through ECMO course.

RESULTS

Eighty-nine patients were included (35 COVID-19 vs 54 non-COVID-19). Forty (74%) of the non-COVID-19 patients had influenza virus. Prior to cannulation, COVID-19 patients had longer ventilator duration (3 vs 1 day, p = .003), higher PaCO2 (64 vs 53 mmHg, p = .012), and white blood cell count (14 vs 9 ×103/μL, p = .004). Overall in-hospital mortality was 33.7% (n = 30). COVID-19 patients had a higher mortality (49% vs. 24%, p = .017) when compared to non-COVID-19 patients. COVID-19 survivors had longer median time on ECMO than non-COVID-19 survivors (24.4 vs 16.5 days p = .03) but had a similar hospital length of stay (HLOS) (41 vs 48 Extracorporeal Membrane Oxygenationdays p = .33).

CONCLUSION

COVID-19 patients supported with VV ECMO have a higher mortality than non-COVID-19 patients. While COVID-19 survivors had significantly longer VV ECMO runs than non-COVID-19 survivors, HLOS was similar. This data add to a growing body of literature supporting the use of ECMO for potentially reversible causes of respiratory failure.

Extracorporeal membrane oxygenation for COVID-19 and influenza associated acute respiratory distress syndrome: a systematic review

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used extensively for H1N1 influenza and coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) to improve gas exchange and quickly correct hypoxemia and hypercapnia. This systematic review summarized the evidence on ECMO for the treatment of COVID-19 and influenza-associated ARDS.

RESEARCH DESIGN AND METHODS

This is a systematic review and meta-analysis of studies to compare the efficacy and safety of ECMO with conventional mechanical ventilation in adults with COVID-19 and influenza-associated ARDS. The study performed a structured search on PubMed, Embase, Web of Science, Scopus and The Cochrane Library. The primary outcome was hospital mortality.

RESULTS

The study included 15 observational studies with 5239 patients with COVID-19 and influenza-associated ARDS. The use of ECMO significantly reduced in-hospital mortality in COVID-19-associated ARDS (OR = 0.40; 95% CI = 0.27-0.58; P < 0.00001) but did not reduce influenza-related mortality (OR = 1.08; 95% CI = 0.41-2.87; P = 0.87). Moreover, ECMO treatment meaningfully increased the incidence of bleeding complications (OR = 7.66; 95% CI = 2.47-23.72; P = 0.0004).

CONCLUSION

The use of ECMO significantly reduced in-hospital mortality in COVID-19- associated ARDS, which may be related to the advances in ECMO-related techniques and the increased experience of clinicians. However, the incidence of bleeding complications remains high. [Figure: see text].

A descriptive evaluation of causes of death in venovenous extracorporeal membrane oxygenation

Veno-venous extracorporeal membrane oxygenation (VV ECMO) has become an important support modality for patients with acute respiratory failure refractory to optimal medical therapy, such as low tidal volume mechanical ventilator support, early paralytic infusion, and early prone positioning. The objective of this cohort study was to investigate the causes and timing of in-hospital mortality in patients on VV ECMO. All patients, excluding trauma and bridge to lung transplant, admitted 8/2014-6/2019 to a specialty ICU for VV ECMO were reviewed. Two hundred twenty-five patients were included. In-hospital mortality was 24.4% (n = 55). Most non-survivors (46/55, 84%) died prior to lung recovery and decannulation from VV ECMO. Most common cause of death (COD) for patients who died on VV ECMO was removal of life sustaining therapy (LST) in setting of multisystem organ failure (MSOF) (n = 24). Nine patients died a median of 9 days [6, 11] after decannulation. Most common COD in these patients was palliative withdrawal of LST due to poor prognosis (n = 3). Non-survivors were older and had worse predictive mortality scores than survivors. We found that death in patients supported with VV ECMO in our study most often occurs prior to decannulation and lung recovery. This study demonstrated that the most common cause of death in patients supported with VV ECMO was removal of LST due MSOF. Acute hemorrhage (systemic or intracranial) was not found to be a common cause of death in our patient population.

Outcomes of Minority COVID-19 patients managed with ECMO: A single-center experience

Background

The coronavirus disease 2019 (COVID‐19) pandemic has significantly burdened the global healthcare system since December 2019. Minority populations are found to have a higher incidence of hospitalization and higher mortality when compared to Caucasians. Extracorporeal membrane oxygenation (ECMO) is reserved for COVID‐19 patients who develop respiratory failure refractory to conventional management. To our knowledge, no data has been reported on outcome differences between Minority COVID‐19 patients and Caucasian COVID‐19 patients managed with ECMO. We aimed to investigate the outcome differences between these two groups.

Methods

Our retrospective cohort study had 23 adults (aged 18 and older) diagnosed with COVID‐19 by polymerase chain reaction. All patients developed acute respiratory distress syndrome (ARDS), refractory to conventional treatment, and were managed on ECMO support. The primary outcome of interest was mortality; the secondary outcome was the rate of ECMO‐related complications.

Results

The overall mortality rate of our study was higher (70%) than other reports of the COVID‐19 population on ECMO. Caucasians in our study had more severe respiratory acidosis with carbon dioxide retention and appeared to have a higher mortality rate of 85.7% compared to Minorities (62.5%). No differences in complication rates between these two groups were identified.

Conclusions

Our cohort revealed a high overall mortality rate of COVID‐19 patients on ECMO support. The Caucasian group was observed to have higher mortality than the Minority group. The high overall mortality was likely attributed to the Caucasian group, which had more severe respiratory acidosis before ECMO initiation, a known predictor of poor prognosis in ARDS patients. Our cohort's ethnic composition may also partially explain the high mortality rate since COVID‐19 Minorities are reported to have worse outcomes than Caucasians. Larger and randomized studies are needed to investigate further the mortality and complication differences between Minority and Caucasian patients diagnosed with COVID‐19 and managed by ECMO.

Extracorporeal Membrane Oxygenation Support for Influenza A: Retrospective Review of the Extracorporeal Life Support Organization Registry Comparing H1N1 With Other Subtypes

Supplemental Digital Content is available in the text.

OBJECTIVES:

Although there is a substantial published experience of extracorporeal membrane oxygenation during the H1N1 pandemic, less is known about the use of extracorporeal membrane oxygenation in patients with other subtypes of the influenza A virus. We hypothesized that the severity of illness and survival of patients supported with extracorporeal membrane oxygenation would differ for those with H1N1 influenza A compared with other subtypes of influenza A.

DESIGN, SETTING, PATIENTS:

Retrospective study of extracorporeal membrane oxygenation–supported adults (> 18 yr) with influenza A viral infection reported to the Extracorporeal Life Support Organization Registry between 2009 and 2019. We describe the frequency and compare characteristics and factors associated with in-hospital survival using a least absolute shrinkage and selection operator regression analysis.

MAIN OUTCOMES AND MEASURES:

Of 2,461 patients supported with extracorporeal membrane oxygenation for influenza A, 445 had H1N1, and 2,004 had other subtypes of influenza A. H1N1 was the predominant subtype between 2009 and 2011. H1N1 patients were younger, with more severe illness at extracorporeal membrane oxygenation cannulation and higher reported extracorporeal membrane oxygenation complications than those with other influenza A subtypes. Patient characteristics including younger age and higher weight and patient management characteristics including longer ventilation duration before extracorporeal membrane oxygenation were associated with worse survival. Extracorporeal membrane oxygenation complications were associated with reduced survival. There was no difference in survival to hospital discharge according to influenza subtype after adjusting for other characteristics.

CONCLUSIONS:

Patients supported with extracorporeal membrane oxygenation for H1N1 were younger, with more severe illness than those supported for other influenza A subtypes. Survival to hospital discharge was associated with patient characteristics, management characteristics, and extracorporeal membrane oxygenation complications but was not impacted by the specific influenza A subtype.

Defining and understanding the "extra-corporeal membrane oxygenation gap" in the veno-venous configuration: Timing and causes of death

In‐hospital mortality of adult veno‐venous extracorporeal membrane oxygenation (V‐V ECMO) patients remains invariably high. However, little is known regarding timing and causes of in‐hospital death, either on‐ECMO or after weaning. The current review aims to investigate the timing and causes of death of adult patients during hospital admittance for V‐V ECMO, and to define the V‐V ECMO gap, which is represented by the patients that are successfully weaned of ECMO but still die during hospital stay. A systematic search was performed using electronic MEDLINE and EMBASE databases through PubMed. Studies reporting on adult V‐V ECMO patients from January 2006 to December 2020 were screened. Studies that did not report on at least on‐ECMO mortality and discharge rate were excluded from analysis as they could not provide the required information regarding the proposed V‐V ECMO‐gap. Mortality rates on‐ECMO and after weaning, as well as weaning and discharge rates, were analyzed as primary outcomes. Secondary outcomes were the causes of death and complications. Initially, 35 studies were finally included in this review. Merely 24 of these studies (comprising 975 patients) reported on prespecified V‐V ECMO outcomes (on‐ECMO mortality and discharge rate). Mortality on V‐V ECMO support was 27.8% (95% confidence interval (CI) 22.5%‐33.2%), whereas mortality after successful weaning was 12.7% (95% CI 8.8%‐16.6%, defining the V‐V ECMO gap). 72.2% of patients (95% CI 66.8%‐77.5%) were weaned successfully from support and 56.8% (95% CI 49.9%‐63.8%) of patients were discharged from hospital. The most common causes of death on ECMO were multiple organ failure, bleeding, and sepsis. Most common causes of death after weaning were multiorgan failure and sepsis. Although the majority of patients are weaned successfully from V‐V ECMO support, a significant proportion of subjects still die during hospital stay, defining the V‐V ECMO gap. Overall, timing and causes of death are poorly reported in current literature. Future studies on V‐V ECMO should describe morbidity and mortality outcomes in more detail in relation to the timing of the events, to improve patient management, due to enhanced understanding of the clinical course.

Critical Care Considerations in Adult Patients With Influenza-Induced ARDS

TOPIC

Acute respiratory distress syndrome is a complex respiratory disease that can be induced by influenza virus infection. Critical care providers are uniquely positioned to manage this pathological progression in adult patients through evidence-based practice.

CLINICAL RELEVANCE

Influenza and subsequent acute respiratory distress syndrome are associated with extremely high morbidity and mortality in adult patients in the United States. Although evidence-based medical management strategies can alter the clinical trajectory of acute respiratory distress syndrome and improve outcomes, critical care providers do not always implement these measures.

PURPOSE

To provide critical care providers with an overview of the pathological progression of influenza-induced acute respiratory distress syndrome and the current evidence-based strategies for management.

CONTENT COVERED

This article reviews the epidemiology and pathophysiology associated with influenza-induced acute respiratory distress syndrome, the criteria for diagnosis, and the evidence-based medical management.

Clinical features and risk factors for severe influenza in children: A study from multiple hospitals in Shanghai

BACKGROUND

The incidence and mortality of influenza in children had risen, but data are limited on children with severe influenza virus infection in China.

METHODS

We conducted a retrospective case-control study and collected the patients' clinical data. Clinical data including demography, clinical presentation, laboratory findings, radiologic findings, treatment and outcomes were collected. Children were clinically confirmed to have virus infection in Shanghai in three hospitals from June 2014 to June 2019.

RESULTS

During the study, 36,047 children were enrolled. Among them, 118 met the criteria for severe flu. Clinical symptoms such as fever, cough, gastrointestinal symptoms, coma and epilepsy were higher in the severe group. Complications such as pneumorrhagia, heart failure, septic shock, acute renal failure and influenza-associated encephalitis were higher in the severe influenza group than the death group. The laboratory findings including decreased hemoglobin, high alanine aminotransferase, high urea nitrogen and high lactate levels were risk factors for death in children with influenza.

CONCLUSION

Influenza-associated encephalopathy (IAE), acute respiratory distress syndrome (ARDS) were the common clinical manifestations and complications for the severe influenza, and delayed use of oseltamivir was found to be associated with fatality.

Is Extracorporeal Membrane Oxygenation the Standard Care for Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a type of acute respiratory failure syndrome characterised by severe respiratory distress and stubborn hypoxaemia. Patients with ARDS have a prolonged hospital stay and high mortality rate. Over long-term follow-up, ARDS is found to be associated with a high incidence of long-term complications and decreased quality of life. Venovenous extracorporeal membrane oxygenation (vv-ECMO) has been widely used for the treatment of refractory ARDS. However, it is not the standard treatment as recommended by ARDS guidelines.

AIM

The aim of this study was to compare the effects of ECMO (vv-ECMO) and conventional mechanical ventilation (CMV) on the clinical outcomes in patients with ARDS.

METHOD

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Medline, EMBASE, Web of Science, and PubMed databases up to November 2019. We selected appropriate studies according to our inclusion and exclusion criteria, and extracted and analysed the data using RevMan 5.0 software to evaluate the effectiveness of ECMO systematically.

RESULTS

A total of 18 articles and 2,399 patients were included in this meta-analysis: 898 patients in the ECMO group and 1,501 patients in the CMV group. Treatment with ECMO may be associated with reduced 1-year mortality (95% confidence interval [CI], 0.27-0.83; p=0.009) and 60-day mortality (95% CI, 0.37-0.86; p=0.008), but increased Intensive Care Unit mortality (95% CI, 1.26-2.36; p=0.0007) of patients with ARDS. Extracorporeal membrane oxygenation may not be related to 30-day mortality or complications such as nosocomial pneumonia, haemorrhagic stroke, or continuous renal replacement therapy in patients with ARDS. However, some results showed heterogeneity, such as bleeding complications and in-hospital mortality. Subgroup analysis showed that ECMO treatment might increase ICU mortality (p=0.002) and nosocomial pneumonia complications (p=0.03) in patients with H1N1 ARDS.

CONCLUSIONS

Compared with CMV, ECMO contributed to lower 60-day and 1-year mortality, and increased ICU mortality in patients with ARDS. However, H1N1 ARDS was independently associated with higher ICU mortality and nosocomial pneumonia. The results were not affected by removing retrospective control studies or articles published >20 years ago from the sensitivity analysis. This meta-analysis demonstrates the effectiveness of ECMO and its importance in standard treatment of patients with ARDS.

Comparative outcomes between COVID-19 and influenza patients placed on veno-venous extracorporeal membrane oxygenation for severe ARDS

BACKGROUND

ECMO is an established supportive adjunct for patients with severe, refractory ARDS from viral pneumonia. However, the exact role and timing of ECMO for COVID-19 patients remains unclear.

METHODS

We conducted a retrospective comparison of the first 32 patients with COVID-19-associated ARDS to the last 28 patients with influenza-associated ARDS placed on V-V ECMO. We compared patient factors between the two cohorts and used survival analysis to compare the hazard of mortality over sixty days post-cannulation.

RESULTS

COVID-19 patients were older (mean 47.8 vs. 41.2 years, p = 0.033), had more ventilator days before cannulation (mean 4.5 vs. 1.5 days, p < 0.001). Crude in-hospital mortality was significantly higher in the COVID-19 cohort at 65.6% (n = 21/32) versus 36.3% (n = 11/28, p = 0.041). The adjusted hazard ratio over sixty days for COVID-19 patients was 2.81 (95% CI 1.07, 7.35) after adjusting for age, race, ECMO-associated organ failure, and Charlson Comorbidity Index.

CONCLUSION

ECMO has a role in severe ARDS associated with COVID-19 but providers should carefully weigh patient factors when utilizing this scarce resource in favor of influenza pneumonia.

Decreased CO2 Levels as Indicators of Possible Mechanical Ventilation-Induced Hyperventilation in COVID-19 Patients: A Retrospective Analysis

Background: Six months since the outbreak of coronavirus disease (COVID-19), the pandemic continues to grow worldwide, although the outbreak in Wuhan, the worst-hit area, has been controlled. Thus, based on the clinical experience in Wuhan, we hypothesized that there is a relationship between the patient's CO₂ levels and prognosis.

Methods: COVID-19 patients' information was retrospectively collected from medical records at the Leishenshan Hospital, Wuhan. Logistic and Cox regression analyses were conducted to determine the correlation between decreased CO₂ levels and disease severity or mortality risk. The Kaplan-Meier curve analysis was coupled with the log-rank test to understand COVID-19 progression in patients with decreased CO₂ levels. Curve fitting was used to confirm the correlation between computed tomography scores and CO₂ levels.

Results: Cox regression analysis showed that the mortality risk of COVID-19 patients correlated with decreased CO₂ levels. The adjusted hazard ratios for decreased CO₂ levels in COVID-19 patients were 8.710 [95% confidence interval (CI): 2.773–27.365, P < 0.001], and 4.754 (95% CI: 1.380–16.370, P = 0.013). The adjusted odds ratio was 0.950 (95% CI: 0.431–2.094, P = 0.900). The Kaplan-Meier survival curves demonstrated that patients with decreased CO₂ levels had a higher risk of mortality.

Conclusions: Decreased CO₂ levels increased the mortality risk of COVID-19 patients, which might be caused by hyperventilation during mechanical ventilation. This finding provides important insights for clinical treatment recommendations.

[Viruso-bacterial pneumonia, complicated by lightness pulmonary bleeding with death]

Despite the significant achievements and successes of medical science, the incidence of influenza, its complications and socio-economic damage do not decrease, remaining at a high level. In the clinic of Mechnikov North-Western State Medical University from December 2018 to February 2019, from 89 hospitalized patients with pneumonia/acute bronchitis viral etiology was determined in 29 (32%). In 27 (97%) patients it was virus A (H1N1), in 2 cases A (H3N2). 9 (31%) patients were sever and were hospitalized in intensive care unit. The case of severe viral pneumonia caused by A (H3N2) complicated by fulminant pulmonary hemorrhage with a lethal outcome is presented.

Extracorporeal Membrane Oxygenation for Coronavirus Disease 2019-Induced Acute Respiratory Distress Syndrome: A Multicenter Descriptive Study

OBJECTIVES

Severe acute respiratory distress syndrome is complicated with coronavirus disease 2019 and extracorporeal membrane oxygenation support may be necessary in severe cases. This study is to summarize the clinical features, extracorporeal membrane oxygenation characteristics, and outcomes of patients with severe acute respiratory syndrome coronavirus 2 pneumonia received extracorporeal membrane oxygenation.

DESIGN

Descriptive study from two hospitals.

SETTING

The ICUs from university hospitals.

PATIENTS

Patients with severe acute respiratory syndrome coronavirus 2 pneumonia received mechanical ventilation, including those underwent extracorporeal membrane oxygenation from Zhongnan Hospital of Wuhan University and Wuhan Pulmonary Hospital from January 8, 2020, to March 31, 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical records, laboratory results, ventilator parameters, and extracorporeal membrane oxygenation-related data were abstracted from the medical records. One-hundred twenty-nine critically ill patients with severe acute respiratory syndrome coronavirus 2 pneumonia were admitted to ICU of the two referral hospitals. Fifty-nine patients received mechanical ventilation and 21 of them received extracorporeal membrane oxygenation support (fourteen from Zhongnan hospital and seven from Wuhan pulmonary hospital). Compared to mechanical ventilation patients without extracorporeal membrane oxygenation support, there was a tendency of decline in mortality but with no significant difference (no-extracorporeal membrane oxygenation group 24/38 [63.2%] vs extracorporeal membrane oxygenation group 12/21 [57.1%]; p = 0.782). For those patients with extracorporeal membrane oxygenation, 12 patients died and nine survived by April 7, 2020. Among extracorporeal membrane oxygenation patients, the PaCO2 prior to extracorporeal membrane oxygenation was lower (54.40 mm Hg [29.20-57.50 mm Hg] vs 63.20 mm Hg [55.40-72.12 mm Hg]; p = 0.006), and pH prior to extracorporeal membrane oxygenation was higher (7.38 [7.28-7.48] vs 7.23 [7.16-7.33]; p = 0.023) in survivors than nonsurvivors.

CONCLUSIONS

Extracorporeal membrane oxygenation might be an effective salvage treatment for patients with severe acute respiratory syndrome coronavirus 2 pneumonia associated with severe acute respiratory distress syndrome. Severe CO2 retention and acidosis prior to extracorporeal membrane oxygenation indicated a poor prognosis.

Invasive pulmonary aspergillosis complicating severe influenza: epidemiology, diagnosis and treatment

PURPOSE OF REVIEW

Bacterial super-infection of critically ill influenza patients is well known, but in recent years, more and more reports describe invasive aspergillosis as a frequent complication as well. This review summarizes the available literature on the association of invasive pulmonary aspergillosis (IPA) with severe influenza [influenza-associated aspergillosis (IAA)], including epidemiology, diagnostic approaches and treatment options.

RECENT FINDINGS

Though IPA typically develops in immunodeficient patients, non-classically immunocompromised patients such as critically ill influenza patients are at high-risk for IPA as well. The morbidity and mortality of IPA in these patients is high, and in the majority of them, the onset occurs early after ICU admission. At present, standard of care (SOC) consists of close follow-up of these critically ill influenza patients with high diagnostic awareness for IPA. As soon as there is clinical, mycological or radiological suspicion for IAA, antifungal azole-based therapy (e.g. voriconazole) is initiated, in combination with therapeutic drug monitoring (TDM). Antifungal treatment regimens should reflect local epidemiology of azole-resistant Aspergillus species and should be adjusted to clinical evolution. TDM is necessary as azoles like voriconazole are characterized by nonlinear pharmacokinetics, especially in critically ill patients.

SUMMARY

In light of the frequency, morbidity and mortality associated with influenza-associated aspergillosis in the ICU, a high awareness of the diagnosis and prompt initiation of antifungal therapy is required. Further studies are needed to evaluate the incidence of IAA in a prospective multicentric manner, to elucidate contributing host-derived factors to the pathogenesis of this super-infection, to further delineate the population at risk, and to identify the preferred diagnostic and management strategy, and also the role of prophylaxis.

Pulmonary complications of influenza infection: a targeted narrative review

Severe influenza infection represents a leading cause of global morbidity and mortality. Several clinical syndromes that involve a number of organs may be associated with Influenza infection. However, lower respiratory complications remain the most common and serious sequel of influenza infection. These include influenza pneumonia, superinfection with bacteria and fungi, exacerbation of underlying lung disease and ARDS. This review analyzes the available literature on the epidemiology and clinical considerations of these conditions. It also provides an overview of the effects of type of influenza, antiviral therapy, vaccination and other therapies on the outcome of these complications.

Characteristics and Outcomes of Patients with Pulmonary Acute Respiratory Distress Syndrome Infected with Influenza versus Other Respiratory Viruses

Background

Although the frequency of respiratory viral infection in patients with pulmonary acute respiratory distress syndrome (ARDS) is not uncommon, clinical significance of the condition remains to be further elucidated. The purpose of this study was to compare characteristics and outcomes of patients with pulmonary ARDS infected with influenza and other respiratory viruses.

Methods

Clinical data of patients with pulmonary ARDS infected with respiratory viruses January 2014–June 2018 were reviewed. Respiratory viral infection was identified by multiplex reverse transcription–polymerase chain reaction (RT-PCR).

Results

Among 126 patients who underwent multiplex RT-PCR, respiratory viral infection was identified in 46% (58/126): 28 patients with influenza and 30 patients with other respiratory viruses. There was no significant difference in baseline and clinical characteristics between patients with influenza and those with other respiratory viruses. The use of extracorporeal membrane oxygenation (ECMO) was more frequent in patients with influenza than in those with other respiratory viruses (32.1% vs 3.3%, p=0.006). Co-bacterial pathogens were more frequently isolated from respiratory samples of patients with pulmonary ARDS infected with influenza virus than those with other respiratory viruses. (53.6% vs 26.7%, p=0.036). There were no significant differences regarding clinical outcomes. In multivariate analysis, acute physiology and chronic health evaluation II was associated with 30-mortality (odds ratio, 1.158; 95% confidence interval, 1.022–1.312; p=0.022).

Conclusion

Respiratory viral infection was not uncommon in patients with pulmonary ARDS. Influenza virus was most commonly identified and was associated with more co-bacterial infection and ECMO therapy.