Hospital survival rates of patients with acute respiratory failure in modern respiratory intensive care units. An international, multicenter, prospective survey

Understanding ventilator-induced lung injury: The role of mechanical power

Mechanical ventilation stands as a life-saving intervention in the management of respiratory failure. However, it carries the risk of ventilator-induced lung injury. Despite the adoption of lung-protective ventilation strategies, including lower tidal volumes and pressure limitations, mortality rates remain high, leaving room for innovative approaches. The concept of mechanical power has emerged as a comprehensive metric encompassing key ventilator parameters associated with the genesis of ventilator-induced lung injury, including volume, pressure, flow, resistance, and respiratory rate. While numerous animal and human studies have linked mechanical power and ventilator-induced lung injury, its practical implementation at the bedside is hindered by calculation challenges, lack of equation consensus, and the absence of an optimal threshold. To overcome the constraints of measuring static respiratory parameters, dynamic mechanical power is proposed for all patients, regardless of their ventilation mode. However, establishing a causal relationship is crucial for its potential implementation, and requires further research. The objective of this review is to explore the role of mechanical power in ventilator-induced lung injury, its association with patient outcomes, and the challenges and potential benefits of implementing a ventilation strategy based on mechanical power.

Elevation of serum lactate dehydrogenase during methylprednisolone pulse therapy as a predictor of high mortality in acute respiratory failure: A single-center, retrospective study

Background

Corticosteroids are common treatments in certain diseases that cause acute respiratory failure (ARF) and are sometimes administered empirically for patients with critical ARF. Associations between changes in clinical parameters following initiation of steroid pulse therapy and mortality in patients with ARF have not been previously investigated.

Methods

This was a single-center and retrospective cohort study. Parameters on the day of methylprednisolone pulse therapy initiation (day 1) and the day following the end of methylprednisolone therapy (day 4) in patients who were admitted because of ARF and underwent methylprednisolone pulse therapy between October 2008 and July 2021 were reviewed.

Results

A total of 98 patients were included in our analysis, and 45 (46%) died at our hospital. Change in lactate dehydrogenase (LDH) from day 1 to day 4 (ΔLDH) was significantly higher in the in-hospital death group than in the survival group (-68 IU/L in the survival group versus 46 IU/L in the in-hospital death group, p < 0.01). Multivariate logistic analyses showed that age >75 years old (odds ratio (OR), 3.88; 95% confidence interval (CI), 1.38-10.9; p < 0.01), previously diagnosed interstitial lung disease (OR, 3.43; 95% CI, 1.10-10.7; p = 0.03), ΔLDH > 0 (OR, 6.47; 95% CI, 2.30-18.2; p < 0.01), and ΔSequential Organ Failure Assessment score > 0 (OR, 3.06; 95% CI, 1.10-8.51; p = 0.03) were significantly associated with in-hospital mortality.

Conclusions

This study showed that elevation of serum LDH level during methylprednisolone pulse therapy was a predictive factor for high in-hospital mortality in patients with ARF.

Oxygenator impact on peramivir in extra-corporeal membrane oxygenation circuits

INTRODUCTION

This study aims to determine the oxygenator impact on alterations of peramivir (PRV) in a contemporary neonatal/pediatric (1/4-inch) and adolescent/adult (3/8-inch) extra-corporeal membrane oxygenation (ECMO) circuit including the Quadrox-i^® oxygenator.

METHODS

1/4-inch and 3/8-inch, simulated closed-loop ECMO circuits were prepared with a Quadrox-i pediatric and Quadrox-i adult oxygenator and blood primed. Additionally, 1/4-inch and 3/8-inch circuits were also prepared without an oxygenator in series. A one-time dose of PRV was administered into the circuits and serial pre- and post-oxygenator concentrations were obtained at 5-min and 1-, 2-, 3-, 4-, 5-, 6-, 8-, 12-, and 24-h time points. PRV was also maintained in a glass vial, and samples were taken from the vial at the same time periods for control purposes to assess for spontaneous drug degradation.

RESULTS

For the 1/4-in. circuit with an oxygenator, there was < 15% PRV loss, and for the 1/4-in. circuit without an oxygenator, there was < 3% PRV loss during the study period. For the 3/8-in. circuits with an oxygenator, there was < 15% PRV loss, and for the 3/8-in. circuits without an oxygenator, there was < 3% PRV loss during the study period.

CONCLUSION

There was no significant PRV loss over the 24-h study period in either the 1/4-in. or 3/8-in circuit, regardless of the presence of the oxygenator. The concentrations obtained pre- and post-oxygenator appeared to approximate each other, suggesting there may be no drug loss via the oxygenator. This preliminary data suggests PRV dosing may not need to be adjusted for concern of drug loss via the oxygenator. Additional single and multiple dose studies are needed to validate these findings.

Impact of prone positioning duration on the outcome of patients receiving venovenous extracorporeal membrane oxygenation for acute respiratory distress syndrome: A meta-analysis

Purpose

Research has shown that prone positioning (PP) improves the survival of patients receiving venovenous extracorporeal membrane oxygenation (V-V ECMO) for acute respiratory distress syndrome (ARDS). However, the reported impact of PP duration on the outcome of V-V ECMO patients with ARDS varies across studies.

Methods

A meta-analysis approach was used to identify studies that investigated the impact of PP duration on the outcome of ARDS patients who were treated with V-V ECMO; the following databases were used: MEDLINE, Embase, Wanfang, and the China National Knowledge Infrastructure. The primary outcome was cumulative survival. Secondary outcomes were length of stay in an intensive care unit, exchange of arterial blood gases, and adverse events.

Results

A total of 8 studies were included in the final meta-analysis. Patients with longer duration of PP (≥12 h) had a longer survival period (risk ratio: 1.24; 95% confidence interval: 1.00, 1.54]) than those with PP < 12 h. There was no evidence of publication bias across the studies.

Conclusion

Our results imply that a longer duration of PP ≥ 12 h might improve the outcome of patients with ARDS who receive V-V ECMO therapy.

Adult ECMO in the En Route Care Environment: Overview and Practical Considerations of Managing ECMO Patients During Transport

Purpose of Review

The authors’ experience as a part of the U.S. Military ECMO program to include the challenges and successes learned from over 200 transports via ground and air is key to the expertise provided to this article. We review the topic of ECMO transport from a historical context in addition to current capabilities and significant developments in transport logistics, special patient populations, complications, and our own observations and approaches to include team complement and feasibility.

Recent Findings

ECMO has become an increasingly used resource during the last couple of decades with considerable increase during the Influenza pandemic of 2009 and the current COVID-19 pandemic. This has led to a corresponding increase in the air and ground transport of ECMO patients.

Summary

As centralized ECMO resources become available at health care centers, the need for safe and effective transport of patients on ECMO presents an opportunity for ongoing evaluation and development of safe practices.

Whole-lung finite-element models for mechanical ventilation and respiratory research applications

Mechanical ventilation has been a vital treatment for Covid-19 patients with respiratory failure. Lungs assisted with mechanical ventilators present a wide variability in their response that strongly depends on air-tissue interactions, which motivates the creation of simulation tools to enhance the design of ventilatory protocols. In this work, we aim to create anatomical computational models of the lungs that predict clinically-relevant respiratory variables. To this end, we formulate a continuum poromechanical framework that seamlessly accounts for the air-tissue interaction in the lung parenchyma. Based on this formulation, we construct anatomical finite-element models of the human lungs from computed-tomography images. We simulate the 3D response of lungs connected to mechanical ventilation, from which we recover physiological parameters of high clinical relevance. In particular, we provide a framework to estimate respiratory-system compliance and resistance from continuum lung dynamic simulations. We further study our computational framework in the simulation of the supersyringe method to construct pressure-volume curves. In addition, we run these simulations using several state-of-the-art lung tissue models to understand how the choice of constitutive models impacts the whole-organ mechanical response. We show that the proposed lung model predicts physiological variables, such as airway pressure, flow and volume, that capture many distinctive features observed in mechanical ventilation and the supersyringe method. We further conclude that some constitutive lung tissue models may not adequately capture the physiological behavior of lungs, as measured in terms of lung respiratory-system compliance. Our findings constitute a proof of concept that finite-element poromechanical models of the lungs can be predictive of clinically-relevant variables in respiratory medicine.

Mean platelet volume as a predictive biomarker for in-hospital mortality in patients receiving invasive mechanical ventilation

Background

Although mean platelet volume (MPV) has been reported to be associated with poor prognosis of various critical illness, the relationship between MPV and in-hospital mortality among patients undergoing invasive mechanical ventilation (IMV) is unclear.

Methods

A retrospective observational study including patients receiving IMV was conducted from January, 2014 to January, 2019. The patients were divided into two groups by MPV cutoff value. The receiver operating characteristics curve was used to evaluate the predictive ability of MPV for in-hospital mortality. Univariate and multivariate Cox regression analysis were conducted to analyze the value of MPV for predicting in-hospital mortality. Kaplan–Meier cumulative incidence curve was employed to observe the incidence of in-hospital mortality.

Results

A total of 274 patients were enrolled in the study, and 42 patients (15.3%) died in hospital. MPV > 11.4 fl was a valuable predictor for in-hospital mortality (AUC0.848; 95%CI, 0.800–0.889) with sensitivity 66.7%, and specificity = 86.21%. MPV > 11.4 fl was an independent risk factor for in-hospital mortality (adjusted HR 2.640, 95%CI, 1.208–5.767, P = 0.015). Compared to the group of MPV ≤ 11.4 fl, patients with MPV > 11.4 fl had increased mortality (log-rank test = 40.35, HR = 8.723, P < 0.0001). The relationship between MPV and in-hospital mortality was stronger in female patients than in male patients.

Conclusion

MPV > 11.4 fl is a more useful marker for predicting in-hospital mortality among critically ill patients receiving IMV, especially in female patients. Attention to the MPV marker is simple and profitable with immediate applicability in daily clinical practice.

In-hospital mortality of critically Ill patients with interactions of acute kidney injury and acute respiratory failure in the resource-limited settings: Results from SEA-AKI study

PURPOSE

Our goal was to describe clinical outcomes and explore the physiological interactions between acute kidney injury (AKI) and acute respiratory failure (ARF) in critically ill patients.

MATERIALS AND METHODS

Data were retrieved from the SEA-AKI study, a multinational multicenter database of adult ICUs from Thailand, Laos, and Indonesia. AKI was defined using KDIGO criteria stage 2-3. ARF was defined by being mechanically ventilated. Patients were assigned into 6 patterns based on AKI and ARF sequence: "no AKI/ARF", "ARF alone", "AKI alone", "ARF first", "AKI first", and "Concurrent AKI-ARF". The primary outcome was in-hospital mortality of each pattern.

RESULTS

A final cohort of 5468 patients were eligible for the analysis. The "Concurrent AKI-ARF" had the highest in-hospital mortality of 69.6%. The "AKI first" and the "ARF first" had in-hospital mortality of 54.4% and 53%, respectively. Among patients with single organ failure, in-hospital mortality was 14.6% and 31.5% in the "AKI alone" and the "ARF alone", accordingly. In-hospital mortality was 12.4% in patients without AKI and ARF.

CONCLUSION

Critically ill patients with ARF and AKI are at higher risk of in-hospital death. Different patterns of AKI and ARF interaction result in unique clinical outcomes as well as risk factors.

A Case Report of Combat Blast Injury Requiring Combat Casualty Care, Far-Forward ECMO, Air Transport, and All Levels of Military Critical Care

We describe a 34-year-old soldier who sustained a blast injury in Syria resulting in tracheal 5 cm tracheal loss, cervical spine and cord injury with tetraplegia, multiple bilateral rib fractures, esophageal injury, traumatic brain injury, globe evisceration, and multiple extremity soft tissue and musculoskeletal injuries including a left tibia fracture with compartment syndrome. An emergent intubation of the transected trachea was performed in the field, and the patient was resuscitated with whole blood prehospital. During transport to the Role 2, the patient required cardiopulmonary resuscitation for cardiac arrest. On arrival, he underwent a resuscitative thoracotomy and received a massive transfusion exclusively with whole blood. A specialized critical care team transported the patient to the Role 3 hospital in Baghdad, and the DoD extracorporeal membrane oxygenation (ECMO) team was activated secondary to his unstable airway and severe hypoxia secondary to pulmonary blast injury. The casualty was cannulated in Baghdad approximately 40 hours after injury with bifemoral cannulae in a venovenous configuration. He was transported from Iraq to the U.S. Army Institute of Surgical Research Burn Center in San Antonio without issue. Extracorporeal membrane oxygenation support was successfully weaned, and he was decannulated on ECMO day 4. The early and en route use of venovenous ECMO allowed for maintenance of respiratory support during transport and bridge to operative management and demonstrates the feasibility of prolonged ECMO transport in critically ill combat casualties.

The effect of high flow nasal oxygen therapy in intensive care units: a systematic review and meta-analysis

BACKGROUND

High flow nasal oxygen (HFNO) therapy has been widely used in intensive care units (ICU); however, its efficacy remains inconclusive. This systematic review and meta-analysis aimed to compare the efficacy of HFNO therapy with th at of alternative noninvasive oxygen therapies such as conventional oxygen therapy (COT) and noninvasive ventilation (NIV) in ICU.

METHODS

A Pubmed, Embase, Web of Science, Cochrane Library database search was performed in March 2020. Results: The meta-analysis ultimately included 17 clinical studies. Compared with the overall effect of COT and NIV, HFNO was associated with a low incidence of pneumonia (95% CI: 0.6-0.99, P = 0.04) and improvement in lowest pulse oxygen saturation (SpO₂) during oxygenation (95% CI: 0.02-1.61; P = 0.04). However, no differences were detected in the following outcomes: length of ICU stay, the rate of intubation or reintubation, mortality at day 28, hospital mortality, and SpO₂ at the end of oxygen therapy (all P > 0.05).

CONCLUSIONS

In adult patients in ICU, HFNO may improve oxygenation and decrease pneumonia rate without affecting the length of ICU stay, intubation or reintubation rate, mortality, and SpO₂ at the end of oxygen therapy.

Extracorporeal support for trauma: A trauma quality improvement project (TQIP) analysis in patients with acute respiratory distress syndrome

INTRODUCTION

The use of extracorporeal membrane oxygenation (ECMO) in trauma patients with severe acute respiratory distress syndrome (ARDS) continues to evolve. The objective of this study was to perform a comparative analysis of trauma patients with ARDS who received ECMO to a propensity matched cohort of patients who underwent conventional management.

METHODS

The Trauma Quality Improvement Program (TQIP) database was queried from 2013 to 2016 for all patients with ARDS and those who received ECMO. Demographics, as well as clinical, injury, intervention, and outcome data were collected and analyzed. Patients with ARDS were divided into two groups, those who received ECMO and those who did not. A propensity score analysis was performed using the following criteria: age, gender, vital signs (HR, SBP) and GCS on admission, Injury Severity Score (ISS), and Abbreviated Injury Scale (AIS) score in several body regions. Outcomes between the groups were subsequently compared using univariate as well as Cox regression analyses. Secondary outcomes such as hospitalization (HLOS), ICU length-of-stay (LOS) and ventilation days stratified for patient demographics, timing of ECMO and anticoagulation status were compared.

RESULTS

Over the 3-year study period, 8990 patients with ARDS were identified from the TQIP registry. Following exclusion, 3680 were included in the final analysis, of which 97 (2.6%) received ECMO. On univariate analysis following matching, patients who underwent ECMO had lower overall hospital mortality (23 vs 50%, p < 0.001) with higher rates of complications (p < 0.005), including longer HLOS. In those undergoing ECMO, early initiation (<7 days) was associated with shorter HLOS, ICU LOS, and fewer ventilator days. No difference was observed between the two groups with regard to anticoagulation.

CONCLUSION

Extracorporeal membrane oxygenation use in trauma patients with ARDS may be associated with improved survival, especially for young patients with thoracic injuries, early in the course of ARDS. Anticoagulation while on circuit was not associated with increased risk of hemorrhage or mortality, even in the setting of head injuries. The mortality benefit suggested with ECMO comes at the expense of a potential increase in complication rate and prolonged hospitalization.

Evolution of the United States Military Extracorporeal Membrane Oxygenation Transport Team

INTRODUCTION

The use of extracorporeal membrane oxygenation (ECMO) for the care of critically ill adult patients has increased over the past decade. It has been utilized in more austere locations, to include combat wounded. The U.S. military established the Acute Lung Rescue Team in 2005 to transport and care for patients unable to be managed by standard medical evacuation resources. In 2012, the U.S. military expanded upon this capacity, establishing an ECMO program at Brooke Army Medical Center. To maintain currency, the program treats both military and civilian patients.

MATERIALS AND METHODS

We conducted a single-center retrospective review of all patients transported by the sole U.S. military ECMO program from September 2012 to December 2019. We analyzed basic demographic data, ECMO indication, transport distance range, survival to decannulation and discharge, and programmatic growth.

RESULTS

The U.S. military ECMO team conducted 110 ECMO transports. Of these, 88 patients (80%) were transported to our facility and 81 (73.6%) were cannulated for ECMO by our team prior to transport. The primary indication for ECMO was respiratory failure (76%). The range of transport distance was 6.5 to 8,451 miles (median air transport distance = 1,328 miles, median ground transport distance = 16 miles). In patients who were cannulated remotely, survival to decannulation was 76% and survival to discharge was 73.3%.

CONCLUSIONS

Utilization of the U.S. military ECMO team has increased exponentially since January 2017. With an increased tempo of transport operations and distance of critical care transport, survival to decannulation and discharge rates exceed national benchmarks as described in ELSO published data. The ability to cannulate patients in remote locations and provide critical care transport to a military medical treatment facility has allowed the U.S. military to maintain readiness of a critical medical asset.

Effects of hypercapnia in sepsis: A scoping review of clinical and pre-clinical data

BACKGROUND

Perform a scoping review of (1) pre-clinical studies testing the physiological effects of higher PaCO2 levels in the setting of sepsis models and (2) clinical investigations testing the effects of hypercapnia on clinical outcomes in mechanically ventilated patients with sepsis.

METHODS

We performed a search of CENTRAL, PUBMED, CINAHL, and EMBASE. Study inclusion criteria for pre-clinical studies were: (1) bacterial sepsis model (2) measurement of PaCO2 , and (3) comparison of outcome measure between different PaCO2 levels. Inclusion criteria for clinical studies were: (1) diagnosis of sepsis, (2) receiving invasive mechanical ventilation, (3) measurement of PaCO2 , and (4) comparison of outcomes between different PaCO2 levels. We performed a qualitative analysis to collate and summarize the physiological and clinical effects of hypercapnia according to the recommended methodology from the Cochrane Handbook.

RESULTS

Fifteen pre-clinical and nine clinical studies were included. Among pre-clinical studies, the individual studies found higher PaCO2 augments tissue blood flow and oxygenation, and attenuates inflammation and lung injury; however, all pre-clinical studies were found to have some degree of risk of bias. Six of the nine clinical studies were deemed to be good quality. Among clinical studies hypercapnia was associated with increased cerebral perfusion and oxygenation; however, there were conflicting results testing the association between hypercapnia and mortality.

CONCLUSION

While individual pre-clinical studies identified potential mechanisms by which changes in PaCO2 levels could affect pathophysiology in sepsis, there is a paucity of clinical data as to the optimal PaCO2 range, demonstrating a need for future research.

REGISTRATION

PROSPERO number CRD42018086703.

Veno-Venous Extracorporeal Lung Support as a Bridge to or Through Lung Volume Reduction Surgery in Patients with Severe Hypercapnia

Extracorporeal lung support (ECLS) represents an essential support tool especially for critically ill patients undergoing thoracic surgical procedures. Lung volume reduction surgery (LVRS) is an important treatment option for end-stage lung emphysema in carefully selected patients. Here, we report the efficacy of veno-venous ECLS (VV ECLS) as a bridge to or through LVRS in patients with end-stage lung emphysema and severe hypercapnia. Between January 2016 and May 2017, 125 patients with end-stage lung emphysema undergoing LVRS were prospectively enrolled into this study. Patients with severe hypercapnia caused by chronic respiratory failure were bridged to or through LVRS with low-flow VV ECLS (65 patients, group 1). Patients with preoperative normocapnia served as a control group (60 patients, group 2). In group 1, VV ECLS was implemented preoperatively in five patients and in 60 patients intraoperatively. Extracorporeal lung support was continued postoperatively in all 65 patients. Mean length of postoperative VV ECLS support was 3 ± 1 day. The 90 day mortality rate was 7.8% in group 1 compared with 5% in group 2 (p = 0.5). Postoperatively, a significant improvement was observed in quality of life, exercise capacity, and dyspnea symptoms in both groups. VV ECLS in patients with severe hypercapnia undergoing LVRS is an effective and well-tolerated treatment option. In particular, it increases the intraoperative safety, supports de-escalation of ventilatory strategies, and reduces the rate of postoperative complications in a cohort of patients considered "high risk" for LVRS in the current literature.

Elevated plasma phenylalanine predicts mortality in critical patients with heart failure

Aims

Previous studies found a relationship between elevated phenylalanine levels and poor cardiovascular outcomes. Potential strategies are available to manipulate phenylalanine metabolism. This study investigated whether increased phenylalanine predicted mortality in critical patients with either acute heart failure (HF) or acute on chronic HF, and its correlation with inflammation and immune cytokines.

Methods and results

This study recruited 152 subjects, including 115 patients with HF admitted for critical conditions and 37 normal controls. We measured left ventricular ejection fraction (LVEF), plasma concentrations of phenylalanine, C‐reactive protein, albumin, pre‐albumin, transferrin, and pro‐inflammatory and immune cytokines. Acute Physiology and Chronic Health Evaluation (APACHE II), Sequential Organ Failure Assessment (SOFA), and maximal vasoactive–inotropic scores (VIS_max) were calculated. Patients were followed up until death or a maximum of 1 year. The primary endpoint was all‐cause death. Of the 115 patients, 37 (32.2%) were admitted owing to acute HF, and 78 (67.8%) were admitted owing to acute on chronic HF; 64 (55.7%) had ST elevation/non‐ST elevation myocardial infarction. An LVEF measured during the hospitalization of <40%, 40–50%, and ≥50% was noted in 51 (44.3%), 15 (13.1%), and 49 (42.6%) patients, respectively. During 1 year follow‐up, 51 (44.3%) patients died. Death was associated with higher APACHE II, SOFA, and VIS_max scores; higher levels of C‐reactive protein and phenylalanine; higher incidence of atrial fibrillation and use of inotropic agents; lower cholesterol, albumin, pre‐albumin, and transferrin levels; and significant changes in pro‐inflammatory and immune cytokines. Phenylalanine levels demonstrated an area under the receiver operating characteristic curve of 0.80 for mortality, with an optimal cut‐off value set at 112 μM. Phenylalanine ≥ 112 μM was associated with a higher mortality rate than was phenylalanine < 112 μM (80.5% vs. 24.3%, P < 0.001) [hazard ratio = 5.07 (2.83–9.05), P < 0.001]. The Kaplan–Meier curves revealed that phenylalanine ≥ 112 μM was associated with a lower accumulative survival rate (log rank = 36.9, P < 0.001). Higher phenylalanine levels were correlated with higher APACHE II and SOFA scores, higher C‐reactive protein levels and incidence of using inotropic agents, and changes in cytokines suggestive of immunosuppression, but lower levels of pre‐albumin and transferrin. Further multivariable analysis showed that phenylalanine ≥ 112 μM predicted death over 1 year independently of age, APACHE II and SOFA scores, atrial fibrillation, C‐reactive protein, cholesterol, pre‐albumin, transferrin, and interleukin‐8 and interleukin‐10.

Conclusions

Elevated phenylalanine levels predicted mortality in critical patients, phenotypically predominantly presenting with HF, independently of traditional prognostic factors and cytokines associated with inflammation and immunity.

Survival of mechanically ventilated patients admitted to intensive care units. Results from a tertiary care center between 2016-2018

Objectives:

To estimate the survival of adult and pediatric patients receiving mechanical ventilation and determine the associated risk factors

Methods:

A retrospective cohort study was carried out in the intensive care unit (ICU) at King Abdulaziz Medical City (KAMC) and King Abdullah Children’s Specialist Hospital (KACSH), Riyadh, Saudi Arabia. The analysis includes data from medical records of all patients admitted to ICUs who received mechanical ventilation between 2016-2018. For each patient, potential risk factors were collected. The main outcome of this study was the mortality during the stay in ICU after receiving mechanical ventilation

Results:

A total of 262 adults and 175 pediatric patients were admitted to ICUs and received mechanical ventilation during the study period. For adult patients, the overall mortality was 37%, with a median survival time of 11 days (interquartile range [IQR] 6-20 days). The main risk factors independently associated with the increased mortality rate were being aged 51-60 (odds ratio [OR] 2.6, 95% confidence interval [CI] 6.7-1.0) and factors related to ICU admission. For the pediatric population, the mortality rate was 17%, with a median survival time of 16 days (IQR 7-37 days). Prematurity with respiratory problems was the main recorded cause of initiation of mechanical ventilation (50% of patients). Neonates who had mechanical ventilation within one month of their birth and were born extremely preterm had a high mortality rate after the initiation of mechanical ventilation.

Conclusion:

Both patient age and the causes of the initiation of mechanical ventilation were influencing the survival of patients who required mechanical ventilation.

Two-dimensional echocardiography after return of spontaneous circulation and its association with in-hospital survival after in-hospital cardiopulmonary resuscitation

This retrospective cohort study investigated the association between in-hospital survival and two-dimensional (2D) echocardiography within 24 hours after the return of spontaneous circulation (ROSC) in patients who underwent in-hospital cardiopulmonary resuscitation (ICPR) after in-hospital cardiopulmonary arrest (IHCA). The 2D-echo and non-2D-echo groups comprised eligible patients who underwent transthoracic 2D echocardiography performed by the cardiology team within 24 hours after ROSC and those who did not, respectively. After propensity score (PS) matching, 142 and 284 patients in the 2D-echo and non-2D-echo groups, respectively, were included. A logistic regression analysis showed that the likelihood of in-hospital survival was 2.35-fold higher in the 2D-echo group than in the non-2D-echo group (P < 0.001). Regarding IHCA aetiology, in-hospital survival after cardiac arrest of a cardiac cause was 2.51-fold more likely in the 2D-echo group than in the non-2D-echo group (P < 0.001), with no significant inter-group difference in survival after cardiac arrest of a non-cardiac cause (P = 0.120). In this study, 2D echocardiography performed within 24 hours after ROSC was associated with better in-hospital survival outcomes for patients who underwent ICPR for IHCA with a cardiac aetiology. Thus, 2D echocardiography may be performed within 24 hours after ROSC in patients experiencing IHCA to enable better treatment.

Effect of fluid balance control in critically ill patients: Design of the stepped wedge trial POINCARE-2

A high number of recent studies have shown that a positive fluid balance is independently associated with impaired prognosis in specific populations of patients hospitalized in intensive care unit (ICU): acute kidney injury, acute respiratory distress syndrome (ARDS), sepsis, high risk surgery. However, to date, there is no evidence that control of fluid overload reduces mortality in critically ill patients. The main objective is to assess the efficacy of a strategy limiting fluid overload on mortality in unselected critically ill patients hospitalized in ICU. We hypothesized that a strategy based on a weight-driven recommendation of restricted fluid intake, diuretics, and ultrafiltration initiated from 48 h up to 14 days after admission in critically ill patients would reduce all-cause mortality as compared to usual care. We use a stepped wedge cluster randomized controlled trial combined with a quasi-experimental (before-and-after) study. Patients under mechanical ventilation, admitted since >48 h and < 72 h in ICU, and with no discharge planned for the next 24 h are eligible. A total of 1440 patients are expected to be enrolled in 12 ICUs. Sociodemographic and clinical data are collected at inclusion, and outcomes are collected during the follow-up. Primary outcome is all-cause mortality at 60 days after admission. Secondary outcomes are patients weight differences between admission and day7 (or day 14), 28-day, in-hospital, and 1-year mortality, end-organ damages, and unintended harmful events. Analyses will be held in intention-to-treat. If POINCARE-2 strategy proves effective, then guidelines on fluid balance control might be extended to all critically ill patients. Trial registration: ClinicalTrials.govNCT02765009.

Etiology and Outcomes of ARDS in a Resource Limited Urban Tropical Setting

BACKGROUND

Several studies have been published in the western literature on the incidence, clinical course and outcome of patients with ARDS. However, there is limited data about ARDS in the tropics and moreover, the etiology and outcomes of ARDS in tropical countries are different from those of western nations. In tropical countries like India, resources are limited and costs of therapy play a major role in deciding treatment options. This prospective observational study was designed to analyze the clinical profile, outcomes and predictors of mortality of patients with ARDS in an urban tropical setting.

METHODS

75 patients ≥13 years, admitted in the medical intensive care unit of a teaching hospital in Kerala, India between March 2013 and February 2014, satisfying Berlin definition for ARDS were enrolled in the study. Lung protective ventilation strategy as laid by ARDS Network protocol was followed for every patient on mechanical ventilation. Due to scarcity of ventilators in our institution, invasive ventilation could not be provided for all ARDS patients. The criteria used for patient selection for non-invasive ventilation were hemodynamic stability, well compliant to the use of NIV mask and PaO2/FiO2 ratio >180 at the time of admission.

RESULTS

Out of the 75 patients, 51% were females and the mean age of the study population was 39.8 ± 3.3 years. Common aetiologies were leptospirosis (18.7%), bronchopneumonia (17.3%), scrub typhus and dengue (12% each). Lung injury score and sequential organ failure assessment score scores had statistically significant association with the severity of ARDS. Forty patients (53.3%) received invasive mechanical ventilation and 35 patients were managed with non-invasive ventilation at the time of admission. The mortality in our study was 45%. Altered sensorium (p-0.002), central cyanosis (p-0.024), elevated creatinine (p-0.036), acidosis (p < 0.001), hypotension (p < 0.001), multiorgan dysfunction (p-0.017), PEEP >12 cm H2O (p-0.036), days on ventilator <7 (p-0.014), PaO2/FiO2 Ratio <100 (p < 0.001), LIS>2.5 (p < 0.001) and SOFA score>11 (p < 0.001) were individual predictors of mortality.

CONCLUSION

Tropical infections form a major etiological component of ARDS in a developing country like India. More studies are required for determining criteria for using NIV in mild ARDS patients which would be helpful in resource limited countries. Timely administration of effective antimicrobial therapy in patients in the rural tropics may help to reduce mortality and financial burden due to ARDS.

Optimization of Positive End-Expiratory Pressure Targeting the Best Arterial Oxygen Transport in the Acute Respiratory Distress Syndrome: The OPTIPEP Study

The optimal setting for positive end-expiratory pressure (PEEP) in mechanical ventilation remains controversial in the treatment of acute respiratory distress syndrome (ARDS). The aim of this study was to determine the optimum PEEP level in ARDS, which we defined as the level that allowed the best arterial oxygen delivery (DO2). We conducted a physiologic multicenter prospective study on patients who suffering from ARDS according to standard definition and persistent after 6 hours of ventilation. The PEEP was set to 6 cm H2O at the beginning of the test and then was increased by 2 cm H2O after at least 15 minutes of being stabilized until the plateau pressure achieved 30 cm H2O. At each step, the cardiac output was measured by transesophageal echocardiography and gas blood was sampled. We were able to determine the optimal PEEP for 12 patients. The ratio of PaO2/FiO2 at inclusion was 131 ± 40 with a mean FiO2 of 71 ± 3%. The optimal PEEP level was lower than the higher PEEP despite a constant increase in SaO2. The optimal PEEP levels varied between 8 and 18 cm H2O. Our results show that in patients with ARDS the optimal PEEP differs between each patient and require being determined with monitoring.

Factors determining outcomes in adult patient undergoing mechanical ventilation: A "real-world" retrospective study in an Indian Intensive Care Unit

Background:

Characteristics of patients admitted to intensive care units with respiratory failure (RF) and undergoing mechanical ventilation (MV) have been described for particular indications and diseases, but there are few studies in the general Intensive Care Unit (ICU) population and even lesser from developing countries.

Objective:

This study aims to study clinical characteristics, outcomes, and factors affecting outcomes in adult patients with RF on MV admitted to ICU.

Methods:

A retrospective study of medical records of all patients admitted to ICU between January 1, 2015, and March 31, 2016. Patients receiving MV for more than 6 h were included in the study. Patients younger than 12 years were excluded. Data were recorded of all patients receiving MV during this period regarding demographics, indications for MV, type and characteristics of ventilation, concomitant complications and treatment, and outcomes. Data were recorded at the initiation of MV and daily all throughout the course of MV. The main outcome measure was all-cause mortality at the end of ICU stay.

Results:

Of the 500 patients admitted to the ICU during the period of the study, a total of 122 patients received MV (and were included in study) for mean (standard deviation [SD]) duration of 4 (3.4) days. The mean (SD) stay in ICU and hospital was 4.49 (3.52) and 6.4 (3.6), respectively. Overall mortality for the unselected general ICU patients on MV was 67.21% while that for ARDS patients was 76.1%. The main factors independently associated with increased mortality were (i) pre-MV factors: age, Apache II scores, heart failure (odds ratio [OR], 1.42; 95% confidence interval [CI], 0.54–3.73; P < 0.001); (ii) patient management factors: positive end-expiratory pressure (OR, 2.69; 95% CI, 0.84–8.61; P < 0.001); (iii) Factors occurring over the course of MV: PaO₂/FiO₂ ratio < 100 (OR, 1.66; 95% CI, 0.67–4.11; P < 0.001) and development of renal failure (OR, 2.33; 95% CI, 2.05–2.42; P < 0.001) and hepatic failure (OR, 2.07; 95% CI, 1.91–2.24; P < 0.001) after initiation of MV.

Conclusions:

Outcomes of patients undergoing MV are dependent on various factors (including patient demographics, nature of associated morbidity, characteristics of the MV received, and conditions developing over course of MV) and these factors may be present before or develop after initiation of MV.

Management of mechanical ventilation in patients with hospital-acquired pneumonia: A retrospective, observational study

BACKGROUND

Hospital-acquired pneumonia (HAP) in intensive care patients is a frequent reason for mechanical ventilation (MV). The management of MV and ventilator weaning vary, depending on the type of lung inflammation. This retrospective, observational study screened the data from all patients admitted to the intensive care unit (ICU) of the Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc between 2011 and 2016. The aims were to determine the parameters of pressure-controlled ventilation, the frequencies of tracheostomy, bronchoscopy, reconnection to MV, the length of ICU and hospital stay and the mortality in subgroups with early-/late-onset HAP compared to a subgroup with community-acquired pneumonia (CAP) and patients with MV without pneumonia. The primary outcome of this study was MV length.

RESULTS

Over the study period, a total of 2672 patients were hospitalised. Excluded were 137 organ donors, 66 patient without MV and 20 patients placed on volume-controlled ventilation. The cohort comprised 2.447 patients requiring MV. A total of 1.927 patients (78.7%) were indicated for MV without signs of pneumonia. CAP was diagnosed in 131 patients (5.4%). The criteria for HAP were met by 389 patients (16.0%). Early-onset and late-onset HAP was diagnosed in 63 (2.6%) and 326 (13.3%) patients, respectively. In the subgroups without pneumonia, with CAP, early- and late-onset HAP, the median MV times were 3, 6, 6 and 12 days, respectively, and the median peak inspiratory pressure (Pinsp) of MV was 20, 25, 25 and 27 cm H₂O, respectively. The median positive end-expiratory pressure (PEEP) was 5, 8, 8 and 11 cm H₂O, respectively. The median inspired oxygen concentrations (FiO₂) were 0.45, 0.7, 0.7 and 0.8, respectively. The median length of hospital stays was 8, 15, 15 and 17 days. The mortality rates were 11.4%, 3.8%, 9.5% and 31.3%, respectively.

CONCLUSIONS

During MV, the late-onset HAP subgroup was shown to have the highest Pinsp, PEEP and FiO₂, the longest MV time, ICU and hospital stay, the highest frequency of tracheostomy, reconnection to MV, pulmonary hygiene bronchoscopy and the highest mortality compared to the early-onset HAP and CAP subgroups. The lowest values were found in the mechanically ventilated patients without pneumonia. The differences were due to the severity of lung damage that is graduated from CAP over early-onset HAP after late-onset HAP.

Therapeutic bronchoscopy vs. standard of care in acute respiratory failure: a systematic review

BACKGROUND

We aimed to assess patient-important benefits and harms of therapeutic bronchoscopy vs. standard of care (no bronchoscopy) in critically ill patients with acute respiratory failure (ARF).

METHODS

We conducted a systematic review with meta-analysis and trial sequential analysis (TSA) according to the Cochrane Handbook and GRADE methodology, including a predefined protocol (PROSPERO no. CRD42016046235). We included randomized clinical trials (RCTs) comparing therapeutic bronchoscopy to standard of care in critically ill patients with ARF. Two reviewers independently assessed trials for inclusion, extracted data and assessed risk of bias. Risk ratios (RR) with 95% confidence intervals (CI) were estimated by conventional meta-analysis. The risk of random errors was assessed by TSA. Exclusively patient-important outcomes were evaluated.

RESULTS

We included five trials (n = 212); all were judged as having high risk of bias. There was no difference in all-cause mortality between therapeutic bronchoscopy and standard of care (TSA adjusted RR 0.39; 95% CI 0.14 to 1.07; I² 0%), and only 3% of the required information size had been accrued. There was no difference in ICU length of stay. A shorter duration of mechanical ventilation was suggested by conventional meta-analysis, however TSA highlighted that only 42% of the required information size had been accrued, indicating high risk of random errors. No trials reported data on adverse events, hospital length of stay, quality of life or performance status.

CONCLUSIONS

The quantity and quality of evidence supporting therapeutic bronchoscopy in critically ill patients with ARF is very low with no firm evidence for benefit or harm.

The Effect of ARDS on Survival: Do Patients Die From ARDS or With ARDS?

OBJECTIVE:

To investigate the contribution of acute respiratory distress syndrome (ARDS) in of itself to mortality among ventilated patients.

DESIGN AND SETTING:

A longitudinal retrospective study of ventilated intensive care unit (ICU) patients.

PATIENTS:

The analysis included patients ventilated for more than 48 hours. Patients were classified as having ARDS on admission (early-onset ARDS), late-onset ARDS (ARDS not present during the first 24 hours of admission), or no ARDS. Primary outcomes were mortality at 28 days, and secondary outcomes were 2-year mortality rate from ICU admission.

RESULTS:

A total of 1411 ventilated patients were enrolled: 41% had ARDS on admission, 28.5% developed ARDS during their ICU stay, and 30.5% did not meet the ARDS criteria prior to ICU discharge or death. The non-ARDS group was used as the control. We also divided the cohort based on the severity of ARDS. After adjusting for covariates, mortality risk at 28 days was not significantly different among the different groups. Both early- and late-onset ARDS as well as the severity of ARDS were found to be significant risk factors for 2 years from ICU survival.

CONCLUSION:

Among patients who were ventilated on ICU admission, neither the presence, the severity, or the timing of ARDS contribute independently to the short-term mortality risk. However, acute respiratory distress syndrome does contribute significantly to 2-year mortality risk. This suggests that patients may not die acutely from ARDS itself but rather from the primary disease, and during the acute phase of ARDS, clinicians should focus on improving treatment strategies for the diseases that led to ARDS.

Extracorporeal membrane oxygenation in severe influenza infection with respiratory failure: A systematic review and meta-analysis

Introduction:

Extracorporeal membrane oxygenation (ECMO) has been extensively used for potentially reversible acute respiratory failure associated with severe influenza A (H1N1) pneumonia; however, it remains an expensive, resource-intensive therapy, with a high associated mortality. This systematic review and meta-analysis aims to summarize and pool outcomes data available in the published literature to guide clinical decision-making and further research.

Methods:

We conducted a systematic search of MEDLINE (1966 to April 15, 2015), EMBASE (1980 to April 15, 2015), CENTRAL, and Google Scholar for patients with severe H1N1 pneumonia and respiratory failure who received ECMO. The study validity was appraised by Newcastle–Ottawa Scale. The primary outcome was all-cause mortality. The secondary outcomes were duration of ECMO therapy, mechanical ventilation, and Intensive Care Unit (ICU) length of stay.

Results:

Of 698 abstracts screened and 142 full-text articles reviewed, we included 13 studies with a total of 494 patients receiving ECMO in our final review and meta-analysis. The study validity was satisfactory. The overall mortality was 37.1% (95% confidence interval: 30–45%) limited by underlying heterogeneity (I² = 65%, P value of Q statistic = 0.006). The median duration for ECMO was 10 days, mechanical ventilation was 19 days, and ICU length of stay was 33 days. Exploratory meta-regression did not identify any statistically significant moderator of mortality (P < 0.05), except for the duration of pre-ECMO mechanical ventilation in days (coefficient 0.19, standard error: 0.09, Z = 2.01, P < 0.04, R² = 0.16). The visual inspection of funnel plots did not suggest the presence of publication bias.

Conclusions:

ECMO therapy may be used as an adjunct or salvage therapy for severe H1N1 pneumonia with respiratory failure. It is associated with a prolonged duration of ventilator support, ICU length of stay, and high mortality. Initiating ECMO early once the patient has been instituted on mechanical ventilation may result in improved survival.

Epidemiological analysis of 9,596 patients with acute lung injury at Chinese Military Hospitals

Acute lung injury (ALI) is a common and severe disease that has been associated with significant morbidity and mortality. Understanding the epidemiology of ALI is vital for its prevention and treatment. The present study aimed to analyze the epidemiology of ALI by collecting data from patients that were submitted between 2000 and 2008 into the 'No. 1 Military Medical Project' information system. A total of 9,596 ALI patients were analyzed retrospectively, including 7,284 males (75.91%) and 2,312 females (24.09%). The median age of the patients was 44 years (interquartile range, 31-63 years), and there was a significant difference between the median ages of male and female patients (P<0.01). The number of patients with ALI admitted to the hospitals showed an increasing trend over time. However, there was no significant difference in the annual gender distribution (P>0.05). In addition, ALI was more prevalent in May, July, August, October, November and December, as compared with the other months. ALI occurred at any age, although 40-years-old was the peak age. There was a significant difference in the age group distributions of male and female ALI patients (P<0.01). Among the predisposing conditions, pulmonary contusion represented the highest proportion (45.71%), followed by pneumonia or respiratory tract infection (23.68%) and pulmonary malignant tumor (6.30%). Of the 581 (6.05%) mortalities, pneumonia was the most common cause (37.87%), followed by malignancies (16.87%) and pulmonary embolism (11.02%). However, the highest mortality rate was associated with cardiopulmonary resuscitation (48.28%). In conclusion, the results of the present study suggested that ALI should be increasingly monitored in the future, and predisposing conditions should be regarded as one of the most important features determining the management of ALI.

Can High-flow Nasal Cannula Reduce the Rate of Endotracheal Intubation in Adult Patients With Acute Respiratory Failure Compared With Conventional Oxygen Therapy and Noninvasive Positive Pressure Ventilation?: A Systematic Review and Meta-analysis

BACKGROUND

The effects of high-flow nasal cannula (HFNC) on adult patients with acute respiratory failure (ARF) are controversial. We aimed to further determine the effectiveness of HFNC in reducing the rate of endotracheal intubation in adult patients with ARF by comparison to noninvasive positive pressure ventilation (NIPPV) and conventional oxygen therapy (COT).

METHODS

The PubMed, Embase, Medline, and the Cochrane Central Register of Controlled Trials databases, as well as the Information Sciences Institute Web of Science, were searched for all controlled studies that compared HFNC with NIPPV and COT in adult patients with ARF. The primary outcome was the rate of endotracheal intubation; the secondary outcomes were ICU mortality and length of ICU stay.

RESULTS

Eighteen trials with a total of 3,881 patients were pooled in our final studies. Except for ICU mortality (I² = 67%, χ² = 12.21, P = .02) and rate of endotracheal intubation (I² = 63%, χ² = 13.51, P = .02) between HFNC and NIPPV, no significant heterogeneity was found in outcome measures. Compared with COT, HFNC was associated with a lower rate of endotracheal intubation (z = 2.55, P = .01) while no significant difference was found in the comparison with NIPPV (z = 1.40, P = .16). As for ICU mortality and length of ICU stay, HFNC did not exhibit any advantage over either COT or NIPPV.

CONCLUSIONS

In patients with ARF, HFNC is a more reliable alternative than NIPPV to reduce the rate of endotracheal intubation than COT.

Mechanical ventilation in patients in the intensive care unit of a general university hospital in southern Brazil: an epidemiological study

OBJECTIVES

To determine the characteristics, the frequency and the mortality rates of patients needing mechanical ventilation and to identify the risk factors associated with mortality in the intensive care unit (ICU) of a general university hospital in southern Brazil.

METHOD

Prospective cohort study in patients admitted to the ICU who needed mechanical ventilation for at least 24 hours between March 2004 and April 2007.

RESULTS

A total of 1,115 patients admitted to the ICU needed mechanical ventilation. The mortality rate was 51%. The mean age (± standard deviation) was 57±18 years, and the mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 22.6±8.3. The variables independently associated with mortality were (i) conditions present at the beginning of mechanical ventilation, age (hazard ratio: 1.01; p<0.001); the APACHE II score (hazard ratio: 1.01; p<0.005); acute lung injury/acute respiratory distress syndrome (hazard ratio: 1.38; p=0.009), sepsis (hazard ratio: 1.33; p=0.003), chronic obstructive pulmonary disease (hazard ratio: 0.58; p=0.042), and pneumonia (hazard ratio: 0.78; p=0.013) as causes of mechanical ventilation; and renal (hazard ratio: 1.29; p=0.011) and neurological (hazard ratio: 1.25; p=0.024) failure, and (ii) conditions occurring during the course of mechanical ventilation, acute lung injuri/acute respiratory distress syndrome (hazard ratio: 1.31; p<0.010); sepsis (hazard ratio: 1.53; p<0.001); and renal (hazard ratio: 1.75; p<0.001), cardiovascular (hazard ratio: 1.32; p≤0.009), and hepatic (hazard ratio: 1.67; p≤0.001) failure.

CONCLUSIONS

This large cohort study provides a comprehensive profile of mechanical ventilation patients in South America. The mortality rate of patients who required mechanical ventilation was higher, which may have been related to the severity of illness of the patients admitted to our ICU. Risk factors for hospital mortality included conditions present at the start of mechanical ventilation conditions that occurred during mechanical support.

Epidemiological trends in invasive mechanical ventilation in the United States: A population-based study

PURPOSE

Epidemiological trends for invasive mechanical ventilation (IMV) have not been clearly defined. We sought to define trends for IMV in the United States and assess for disease-specific variation for 3 common causes of respiratory failure: pneumonia, heart failure (HF), and chronic obstructive pulmonary disease (COPD).

METHODS

We calculated national estimates for utilization of nonsurgical IMV cases from the Nationwide Inpatient Sample from 1993 to 2009 and compared trends for COPD, HF, and pneumonia.

RESULTS

We identified 8309344 cases of IMV from 1993 to 2009. Utilization of IMV for nonsurgical indications increased from 178.9 per 100000 in 1993 to 310.9 per 100000 US adults in 2009. Pneumonia cases requiring IMV showed the largest increase (103.6%), whereas COPD cases remained relatively stable (2.5% increase) and HF cases decreased by 55.4%. Similar demographic and clinical changes were observed for pneumonia, COPD, and HF, with cases of IMV becoming younger, more ethnically diverse, and more frequently insured by Medicaid. Outcome trends for patients differed based on diagnosis. Adjusted hospital mortality decreased over time for cases of pneumonia (odds ratio [OR] per 5 years, 0.89; 95% confidence interval [CI], 0.88-0.90) and COPD (OR per 5 years, 0.97; 95% CI, 0.97-0.98) but increased for HF (OR per 5 years, 1.10; 95% CI, 1.09-1.12).

CONCLUSION

Utilization of IMV in the US increased from 1993 to 2009 with a decrease in overall mortality. However, trends in utilization and outcomes of IMV differed markedly based on diagnosis. Unlike favorable outcome trends in pneumonia and COPD, hospital mortality for HF has not improved. Further studies to investigate the outcome gap between HF and other causes of respiratory failure are needed.

[Extracorporeal pulmonary support procedures in intensive care medicine 2014]

BACKGROUND

In recent years a rapid expansion of extracorporeal devices for support of severe lung failure has been witnessed. Systems for veno-venous extracorporeal membrane oxygenation (VV-ECMO) or for extracorporeal carbon dioxide elimination are distinguished depending on the indications.

OBJECTIVES

The state of the art of extracorporeal lung support is presented with an overview of the different systems, the indications, efficiency and potential side effects.

METHODS

By means of a selective literature research and based on personal experience, the principles and techniques, efficiency and potential side-effects of the new modalities are described.

RESULTS

The VV-ECMO systems may be indicated in severe, refractory and predominantly hypoxemic lung failure (pAO2/FIO2 <80 mmHg). Both life-saving gas exchange and a reduction of ventilator-induced lung injury by means of a more protective ventilation can be achieved. Experienced centers can obtain survival rates of more than 60%. Either pumpless arterio-venous devices, also called interventional lung assist (ILA) or low-flow ECMO devices can be used for extracorporeal carbon dioxide elimination in refractory respiratory acidosis. Severe complications can occur with all modalities of extracorporeal support and have to be rapidly recognized and controlled. It must be pointed out that secure evidence based on prospective randomized studies is currently limited for all modalities.

CONCLUSION

Modern extracorporeal lung support devices allow an effective extracorporeal gas exchange and have become an inherent component of intensive care treatment of critically ill patients. Due to potentially severe complications the use should be restricted to specialized centers with experience in the treatment of severe acute respiratory distress syndrome (ARDS).

Extracorporeal membranous oxygenation (ECMO) in polytrauma: what the radiologist needs to know

The purpose of this article is to review the spectrum of severe traumatic injuries treatable with ECMO and their imaging features, considerations for cannula placement, and complications that may arise in polytraumatized patients on extracorporeal life support. Recent major advances in miniaturization and biocompatibility of ECMO devices have dramatically increased their safety profile and expanded the application of ECMO to patients with severe polytrauma.

Does the Mean Arterial Pressure Influence Mortality Rate in Patients with Acute Hypoxemic Respiratory Failure under Mechanical Ventilation?

Background

In sepsis patients, target mean arterial pressures (MAPs) greater than 65 mm Hg are recommended. However, there is no such recommendation for patients receiving mechanical ventilation. We aimed to evaluate the influence of MAP over the first 24 hours after intensive care unit (ICU) admission on the mortality rate at 60 days post-admission in patients showing acute hypoxemic respiratory failure under mechanical ventilation.

Methods

This prospective, multicenter study included 22 ICUs and compared the mortality and clinical outcomes in patients showing acute hypoxemic respiratory failure with high (75-90 mm Hg) and low (65-74.9 mm Hg) MAPs over the first 24 hours of admission to the ICU.

Results

Of the 844 patients with acute hypoxemic respiratory failure, 338 had a sustained MAP of 65-90 mm Hg over the first 24 hours of admission to the ICU. At 60 days, the mortality rates in the low (26.2%) and high (24.5%) MAP groups were not significantly different. The ICU days, hospital days, and 60-day mortality rate did not differ between the groups.

Conclusion

In the first 24 hours of ICU admission, MAP range between 65 and 90 mm Hg in patients with acute hypoxemic respiratory failure under mechanical ventilation may not cause significantly differences in 60-day mortality.

Markers of poor outcome in patients with acute hypoxemic respiratory failure

PURPOSE

This study described the acute hypoxemic respiratory failure (AHRF) population and identified potential modifiable markers of outcome.

METHODS

A prospective, multicenter study was performed in 22 intensive care units (ICUs). The clinical outcomes of patients with acute respiratory distress syndrome (ARDS) were compared to the outcomes in patients with non-ARDS AHRF, and a propensity score matched analysis was performed.

RESULTS

A total 837 patients with an arterial oxygen tension/fraction of inspired oxygen ratio (Pao2/Fio2) less than 300 mm Hg on ICU admission were included. Of these, 163 patients met the criteria defining ARDS, whereas the remaining 674 patients who had unilateral or no pulmonary opacities were classified as non-ARDS AHRF. Baseline Pao2/Fio2 ratio, thrombocytopenia, increased positive end-expiratory pressure (PEEP) were significantly associated with the 60-day mortality in hypoxemic respiratory failure after multivariate analysis. However, ARDS was not associated with increased 60-day mortality when independent predictors for the 60-day mortality and propensity score were controlled. In the case-control study, the 60-day mortality rate was 38.6% in the ARDS group and 32.3% in the non-ARDS AHRF group. In both patients with ARDS and non-ARDS AHRF, the mortality rate increased proportionally to a lower baseline Pao2/Fio2.

CONCLUSION

Lower baseline oxygenation (Pao2/Fio2) is a poor prognostic marker in acute hypoxemic respiratory failure.

Evaluation of the oxygenation index in adult respiratory failure

BACKGROUND

The oxygenation index (mean airway pressure × FIO2 divided by PaO2) was originally devised to measure severity of illness and predict outcome in neonatal respiratory failure. We evaluated the discrimination of a modified oxygenation index (modified with age) for predicting 28-day mortality in adults with respiratory failure (adult respiratory distress syndrome [ARDS]) using the ALVEOLI section of the ARDSNet database and validated the results in the full ARDSNet database.

METHODS

We compared age-adjusted oxygenation index (AOI) on ventilator Days 1 to 4 with 28-day mortality.

RESULTS

AOI correlated positively with mortality (area under the receiver operating characteristic curve, 0.70-0.74, for ARDS Days 1-4). Following initial development, AOI related to mortality was validated in two other ARDSNet databases producing similar results (area under the receiver operating characteristic curve, 0.70-0.78).

CONCLUSION

The observed sensitivity and specificity analysis demonstrated that AOI is equivalent to or better than other mortality prediction systems used for ARDS.

LEVEL OF EVIDENCE

Prognostic, level III.

Extracorporeal pulmonary support in severe pulmonary failure in adults: a treatment rediscovered

BACKGROUND

Severe, acute respiratory failure in adults still carries a high mortality. In recent years, improved pulmonary support techniques have been used increasingly alongside conventional treatment. About 1000 such treatments are performed in Germany annually, and the number is rising rapidly. The two types of systems currently in use involve venovenous extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide elimination.

METHODS

The underlying principles, technical implementation, efficacy, and adverse effects of the new techniques are summarized in the light of a selective review of the literature, supplemented by the authors' personal experience. Recommendations are given for clinical use.

RESULTS

Currently, only limited high-quality data (from prospective randomized trials) are available to support the use of either of these techniques in adults. Veno-venous ECMO systems can effectively secure gas exchange in patients with severe respiratory failure, with experienced centers reporting survival rates from 63% to 75%. Either pump-free arteriovenous systems or low-flow ECMO systems can be used for extracorporeal carbon dioxide elimination. Complications can be serious or life-threatening and must, therefore, be rapidly recognized and treated: these include vascular injury during cannulation, venous thrombosis in a cannulated vessel, an increased hemorrhagic tendency, and thrombocytopenia.

CONCLUSION

Modern miniaturized pulmonary support systems enable protective mechanical ventilation with low tidal volumes, reduce ventilator-associated lung injury, and can improve survival rates in critically ill patients with a manageable adverse effect profile.

Sequential oxygenation index and organ dysfunction assessment within the first 3 days of mechanical ventilation predict the outcome of adult patients with severe acute respiratory failure

OBJECTIVE

To determine early predictors of outcomes of adult patients with severe acute respiratory failure.

METHOD

100 consecutive adult patients with severe acute respiratory failure were evaluated in this retrospective study. Data including comorbidities, Sequential Organ Failure Assessment (SOFA) score, Acute Physiological Assessment and Chronic Health Evaluation II (APACHE II) score, PaO2, FiO2, PaO2/FiO2, PEEP, mean airway pressure (mPaw), and oxygenation index (OI) on the 1st and the 3rd day of mechanical ventilation, and change in OI within 3 days were recorded. Primary outcome was hospital mortality; secondary outcome measure was ventilator weaning failure.

RESULTS

38 out of 100 (38%) patients died within the study period. 48 patients (48%) failed to wean from ventilator. Multivariate analysis showed day 3 OI (P=0.004) and SOFA (P=0.02) score were independent predictors of hospital mortality. Preexisting cerebrovascular accident (CVA) (P=0.002) was the predictor of weaning failure. Results from Kaplan-Meier method demonstrated that higher day 3 OI was associated with shorter survival time (log-Rank test, P<0.001).

CONCLUSION

Early OI (within 3 days) and SOFA score were predictors of mortality in severe acute respiratory failure. In the future, prospective studies measuring serial OIs in a larger scale of study cohort is required to further consolidate our findings.

[Decubitus prone position in patient with extracorporeal CO2 removal device Novalung(®)]

OBJECTIVE

To describe the course of a patient with the extracorporeal CO2 removal device and discover the effect of Novalung on ventilation, considering the patient's prone position and its influence on the device's blood flow. To develop a protocol of managing and specific care of a patient with Novalung.

MATERIAL AND METHODS

A case report of a patient with Novalung in a tertiary hospital ICU unit is reported. Parameters considered are hemodynamic, respiratory, pharmacological, analytical, neuromonitoring, managing of the Novalung and length of decubitus prone cycles. Anova Test, Student's T test, Wilcoxon-Mann Whitney and Spearman correlation. Significance p <0.05.

RESULTS

A 46-year old women with nosocomial pneumonia and acute respiratory failure with indication of Novalung to decrease hypercapnia and optimize ventilatory management of refractory hypoxemia. ICU Stay 26 days, MBP 82 ± 9 mmHg, HR 110 ± 6l pm during the admission, monitoring PICCO 5 days CI 3.2 ± 0.8 l/min/m2, ELWI 33 ± 4 ml, continuous hemofiltration 13.2 days with a median removal 50 cc/h. Norepinephrine dose 0.68 ± 0.79 μ/kg/min for 15 days. Respiratory parameters during the admission: PO2 59 ± 13 mmHg, PCO2 68 ± 35 mmHg, SatO2 85 ± 12%, PO2/FIO2 69 ± 35, tidal volume 389 ± 141 cc. Novalung® 13 days, heparin dose 181.42 ± 145 mIU/Kg/min, Cephalin time 57.56 ± 16.41 sec, O2 flow 7 ± 3 l/min, median blood flow 1030 cc/h, interquartile range 1447-612 cc/h. Prone cycles 4, duration 53 ± 27 hours. With Novalung® PCO2 decreased regardless of position 66 ± 21:56 ± 9, p=0.005. Tidal volume 512 ± 67:267 ± 72, p=0.0001. Blood flow on supine-prone position 1053 ± 82:113 ± 112, p=0.001. There was no link between blood flow and PCO2 (p=0.2) and between O2 and PO2 flow (p=0.05). Specific care: pedal and tibial pulse monitoring, keep circuit safe to prevent and detect signs of bleeding, femoral arterial and venous catheter care, coagulation monitoring.

COMMENTS

During the use of Novalung protective, ventilation, low tidal volumes, decreased pressure plateau, PEEP and hypercapnia were achieved. Blood flow decreased in prone position, but the PCO2 did not increase. The device did not coagulate.

Trends in and perspectives on extracorporeal membrane oxygenation for severe adult respiratory failure

Various approaches such as ventilator management involving lung-protective ventilation, corticosteroids, prone positioning, and nitric oxide have failed to maintain sufficient lung oxygenation or appropriate ventilation competence in very severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) has been aggressively introduced for such patients, although in only a few institutions. The clinical usefulness of ECMO in a large-scale multicenter study (CESAR trial, 2009) and continued development/improvement of ECMO devices have facilitated performance of ECMO, with further increase in the number of institutions adopting ECMO therapy. Clinical usefulness of ECMO was documented in many cases of severe ARDS secondary to influenza A (H1N1) 2009 infection. ECMO requires establishment of an appropriate management system to minimize fatal complications (e.g., hemorrhage), which requires a multidisciplinary team. This, in combination with a new technique, interventional lung assist, will further extend the indications for ECMO. ECMO can be expected to gain importance as a respiratory support technique.

A prognostic index for survival among mechanically ventilated hematopoietic cell transplant recipients

The prognosis of recipients of allogeneic hematopoietic cell transplantation (HCT) who require mechanical ventilation (MV) has historically been poor. Of 883 adults undergoing allogeneic HCT at the University of Minnesota between 1998 and 2009, 179 (20%) required MV before day 100 posttransplantation. We evaluated the outcomes of these patients to develop a prognostic index to predict the 100-day post-MV overall survival (OS) based on factors present at the time of MV. The 179 patients were divided at random into a training set (n = 119) and a validation set (n = 60). The 100-day postventilation OS was 17% for the total population. Multivariate Cox regression on the training set identified creatinine <2 mg/dL and platelet count >20 × 10(9)/L as significant predictors of better OS. Recursive partitioning classified patients with these good prognostic criteria into class A (n = 76); all other patients were classified as class B (n = 103). Among class A patients, 100-day OS was 29% in the training set and 30% in the validation set. Corresponding OS in class B patients was 5% and 15%, respectively. This prognostic index should help guide physicians in counseling HCT patients and their families regarding the use of MV and potential outcomes.

Extracorporeal membrane oxygenation for ARDS in adults

A 41-year-old woman presents with severe community-acquired pneumococcal pneumonia. Chest radiography reveals diffuse bilateral infiltrates, and hypoxemic respiratory failure develops despite appropriate antibiotic therapy. She is intubated and mechanical ventilation is initiated with a volume- and pressure-limited approach for the acute respiratory distress syndrome (ARDS). Over the ensuing 24 hours, her partial pressure of arterial oxygen (Pao2) decreases to 40 mm Hg, despite ventilatory support with a fraction of inspired oxygen (Fio2) of 1.0 and a positive end-expiratory pressure (PEEP) of 20 cm of water. She is placed in the prone position and a neuromuscular blocking agent is administered, without improvement in her Pao2. An intensive care specialist recommends the initiation of extracorporeal membrane oxygenation (ECMO).

Mortality and associated factors in a thoracic surgery ICU

OBJECTIVE

To assess mortality and identify mortality risk factors in patients admitted to a thoracic surgery ICU.

METHODS

We retrospectively evaluated 141 patients admitted to the thoracic surgery ICU of the Denizli State Hospital, located in the city of Denizli, Turkey, between January of 2006 and August of 2008. We collected data regarding gender, age, reason for admission, invasive interventions and operations, invasive mechanical ventilation, infections, and length of ICU stay.

RESULTS

Of the 141 patients, 103 (73.0%) were male, and 38 (23.0%) were female. The mean age was 52.1 years (range, 12-92 years), and the mortality rate was 16.3%. The most common reason for admission was trauma. Mortality was found to correlate with advanced age (p < 0.05), requiring invasive mechanical ventilation (OR = 42.375; p < 0.05), prolonged ICU stay (p < 0.05), and specific reasons for admission-trauma, gunshot wound, stab wound, and malignancy (p < 0.05 for all).

CONCLUSIONS

Among patients in a thoracic surgery ICU, the rates of morbidity and mortality are high. Increased awareness of mortality risk factors can improve the effectiveness of treatment, which should reduce the rates of morbidity and mortality, thereby providing time savings and minimizing costs.

Extracorporeal membrane oxygenation for acute respiratory distress syndrome: is the configuration mode an important predictor for the outcome?

Extracorporeal membrane oxygenation (ECMO) is increasingly applied as rescue-therapy for patients with severe acute respiratory distress syndrome (ARDS). Here, we evaluate the effect of different configuration strategies (venovenous vs. venoarterial vs. veno-venoarterial) on the outcome. From 2006 to 2008, 30 patients received ECMO for severe ARDS. Patients were divided into three groups according to the configuration: veno-venous (vv; n = 11), venoarterial (va; n=8) or veno-venoarterial (vva; n = 11). Data were prospectively collected and endpoint was 30-day mortality. To identify independent risk factors, univariate analysis was performed for clinical parameters, such as age, body mass index, gender, configuration, low-pH, oxygenation index (pO(2)/FiO(2)) and underlying disease. Thirty-day mortality was 53% (n = 16) for all comers: 63% (n = 7) died in the vv-group, 75% (n = 6) in the va-group and 27% (n = 3) in the vva-group. Although univariate analysis could not rule out a significant predictor for the outcome, there was a trend visible to decreased mortality in the vva-group when compared to vv- and va-groups (27% vs. 63% vs. 75%; P = 0.057). ECMO provides a survival benefit in patients when considering a predicted mortality rate of 80% in ARDS. The configuration mode appears to impact the outcome as the veno-venoarterial appears to further improve the survival in this subset of patients.

Shortening ventilatory support with a protocol based on daily extubation screening and noninvasive ventilation in selected patients

BACKGROUND

Prolonged invasive mechanical ventilation and reintubation are associated with adverse outcomes and increased mortality. Daily screening to identify patients able to breathe without support is recommended to reduce the length of mechanical ventilation. Noninvasive positive-pressure ventilation has been proposed as a technique to shorten the time that patients remain on invasive ventilation.

METHODS

We conducted a before-and-after study to evaluate the efficacy of an intervention that combined daily screening with the use of noninvasive ventilation immediately after extubation in selected patients. The population consisted of patients who had been intubated for at least 2 days.

RESULTS

The baseline characteristics were similar between the groups. The intervention group had a lower length of invasive ventilation (6 [4;9] vs. 7 [4;11.5] days, p = 0.04) and total (invasive plus noninvasive) ventilator support (7 [4;11] vs. 9 [6;8], p = 0.01). Similar reintubation rates within 72 hours were observed for both groups. In addition, a lower ICU mortality was found in the intervention group (10.8% vs. 24.3%, p = 0.03), with a higher cumulative survival probability at 60 days (p = 0.05). Multivariate analysis showed that the intervention was an independent factor associated with survival (RR: 2.77; CI 1.14-6.65; p = 0.03), whereas the opposite was found for reintubation at 72 hours (RR: 0.27; CI 0.11-0.65; p = 0.01).

CONCLUSION

The intervention reduced the length of invasive ventilation and total ventilatory support without increasing the risk of reintubation and was identified as an independent factor associated with survival.