Advanced Respiratory Support in the Contemporary Cardiac ICU

Extra-cardiac management of cardiogenic shock in the intensive care unit

Cardiogenic shock (CS) is a heterogeneous clinical syndrome characterized by low cardiac output leading to end-organ hypoperfusion. Organ dysoxia ranging from transient organ injury to irreversible organ failure and death occurs across all CS etiologies but differing by incidence and type. Herein, we review the recognition and management of respiratory, renal and hepatic failure complicating CS. We also discuss unmet needs in the CS care pathway and future research priorities for generating evidence-based best practices for the management of extra-cardiac sequelae. The complexity of CS admitted to the contemporary cardiac intensive care unit demands a workforce skilled to care for these extra-cardiac critical illness complications with an appreciation for how cardio-systemic interactions influence critical illness outcomes in afflicted patients.

Guide to Lung-Protective Ventilation in Cardiac Patients

The incidence of acute respiratory insufficiency has continued to increase among patients admitted to modern-day cardiovascular intensive care units. Positive pressure ventilation (PPV) remains the mainstay of treatment for these patients. Alterations in intrathoracic pressure during PPV has distinct effects on both the right and left ventricles, affecting cardiovascular performance. Lung-protective ventilation (LPV) minimizes the risk of further lung injury through ventilator-induced lung injury and, hence, an understanding of LPV and its cardiopulmonary interactions is beneficial for cardiologists.

Propofol vs etomidate for induction prior to invasive mechanical ventilation in patients with acute myocardial infarction

BACKGROUND

Patients with acute myocardial infarction (AMI) requiring invasive mechanical ventilation (IMV) have a high mortality. However, little is known regarding the impact of induction agents, used prior to IMV, on clinical outcomes in this population. We assessed for the association between induction agent and mortality in patients with AMI requiring IMV.

METHODS

We compared clinical outcomes between those receiving propofol compared to etomidate for induction among adults with AMI between October 2015 and December 2019 using the Vizient® Clinical Data Base, a multicenter, US national database. We used inverse probability treatment weighting (IPTW) to assess for the association between induction agent and in-hospital mortality.

RESULTS

We identified 5,147 patients, 1,386 (26.9%) of received propofol and 3,761 (73.1%) received etomidate for IMV induction. The mean (SD) age was 66.1 (12.4) years, 33.0% were women, and 51.6% and 39.8% presented with STEMI and cardiogenic shock, respectively. Patients in the propofol group were more likely to require preintubation vasoactive medication and mechanical circulatory support (both, P < .05). Utilization of propofol was associated with lower mortality compared to etomidate (32.3% vs 36.1%, P = .01). After propensity weighting, propofol use remained associated with lower mortality (weighted mean difference -4.7%; 95% confidence interval: -7.6% to -1.8%, P = .002). Total cost, ventilator days, and length of stay were higher in the propofol group (all, P < .001).

CONCLUSIONS

Induction with propofol, compared with etomidate, was associated with lower mortality for patients with AMI requiring IMV. Randomized trials are needed to determine the optimal induction agent for this critically ill patient population.

Complex Heart-Lung Ventilator Emergencies in the CICU

This review aims to enhance the comprehension and management of cardiopulmonary interactions in critically ill patients with cardiovascular disease undergoing mechanical ventilation. Highlighting the significance of maintaining a delicate balance, this article emphasizes the crucial role of adjusting ventilation parameters based on both invasive and noninvasive monitoring. It provides recommendations for the induction and liberation from mechanical ventilation. Special attention is given to the identification of auto-PEEP (positive end-expiratory pressure) and other situations that may impact hemodynamics and patients' outcomes.

Noninvasive Ventilation in the Cardiac Intensive Care Unit

Over the last several decades, the cardiac intensive care unit (CICU) has seen an increase in the complexity of the patient population and etiologies requiring CICU admission. Currently, respiratory failure is the most common reason for admission to the contemporary CICU. As a result, noninvasive ventilation (NIV), including noninvasive positive-pressure ventilation and high-flow nasal cannula, has been increasingly utilized in the management of patients admitted to the CICU. In this review, we detail the different NIV modalities and summarize the evidence supporting their use in conditions frequently encountered in the CICU. We describe the unique pathophysiologic interactions between positive pressure ventilation and left and/or right ventricular dysfunction. Additionally, we discuss the evidence and strategies for utilization of NIV as a method to reduce extubation failure in patients who required invasive mechanical ventilation. Lastly, we examine unique considerations for managing respiratory failure in certain, high-risk patient populations such as those with right ventricular failure, severe valvular disease, and adult congenital heart disease. Overall, it is critical for clinicians who practice in the CICU to be experts with the application, risks, benefits, and modalities of NIV in cardiac patients with respiratory failure.

The Changing Epidemiology of the Cardiac Intensive Care Unit

Coronary care units (CCUs) were originally designed to monitor and treat peri-infarction ventricular arrhythmias but have evolved into highly specialized cardiac intensive care units (CICUs) that provide care to a patient population that is increasingly heterogeneous and complex. Paralleling broader epidemiologic trends, patients admitted to contemporary CICUs are older and have a greater burden of cardiovascular and non-cardiovascular comorbidities. Moreover, contemporary CICU patients have high illness severity and often present with acute noncardiac organ dysfunction. In addition to these shifting demographic patterns, there have been important epidemiologic changes in CICU technologies, multidisciplinary systems of care, and physician staffing and training.

Research Priorities in Critical Care Cardiology: JACC Expert Panel

Over the last several decades, the cardiac intensive care unit (CICU) has seen a substantial evolution in the patient population, comorbidities, and diagnoses. However, the generation of high-quality evidence to manage these complex and critically ill patients has been slow. Given the scarcity of clinical trials focused on critical care cardiology (CCC), CICU clinicians are often left to extrapolate from studies that either exclude or poorly represent the patient population admitted to CICUs. The lack of high-quality evidence and limited guidance from society guidelines has led to significant variation in practice patterns for many of the most common CICU diagnoses. Several barriers, both common to critical care research and unique to CCC, have impeded progress. In this multinational perspective, we describe key areas of priority for CCC research, current challenges for investigation in the CICU, and essential elements of a path forward for the field.

Clinical Predictors and Outcomes After Left Ventricular Assist Device Implantation and Tracheostomy

BACKGROUND

Postoperative respiratory failure is a major complication that affects up to 10% of patients who undergo cardiac surgery and has a high in-hospital mortality rate. Few studies have investigated whether patients who require tracheostomy for postoperative respiratory failure after continuous-flow left ventricular assist device (CF-LVAD) implantation have worse survival outcomes than patients who do not.

OBJECTIVE

To identify risk factors for respiratory failure necessitating tracheostomy in CF-LVAD recipients and to compare survival outcomes between those who did and did not require tracheostomy.

METHODS

Consecutive patients who underwent primary CF-LVAD placement at a single institution between August 1, 2002, and December 31, 2019, were retrospectively reviewed. Propensity score matching accounted for baseline differences between the tracheostomy and nontracheostomy groups. Multivariate logistic regression was used to identify tracheostomy risk factors and 90-day survival; Kaplan-Meier analysis was used to assess midterm survival.

RESULTS

During the study period, 664 patients received a CF-LVAD; 106 (16.0%) underwent tracheostomy for respiratory failure. Propensity score matching produced 103 matched tracheostomy-nontracheostomy pairs. Patients who underwent tracheostomy were older (mean [SD] age, 57.9 [12.3] vs 54.6 [13.9] years; P = .02) and more likely to need preoperative mechanical circulatory support (61.3% vs 47.8%; P = .01) and preoperative intubation (27.4% vs 8.8%; P < .001); serum creatinine was higher in the tracheostomy group (mean [SD], 1.7 [1.0] vs 1.4 [0.6] mg/dL; P < .001), correlating with tracheostomy need (odds ratio, 1.76; 95% CI, 1.21-2.56; P = .003). Both before and after propensity matching, 30-day, 60-day, 90-day, and 1-year survival were worse in patients who underwent tracheostomy. Median follow-up was 0.8 years (range, 0.0-11.2 years). Three-year Kaplan-Meier survival was significantly worse for the tracheostomy group before (22.0% vs 61.0%; P < .001) and after (22.4% vs 48.3%; P < .001) matching.

CONCLUSION

Given the substantially increased probability of death in patients who develop respiratory failure and need tracheostomy, those at high risk for respiratory failure should be carefully considered for CF-LVAD implantation. Comprehensive management to decrease respiratory failure before and after surgery is critical.

RIGHT VENTRICULAR DYSFUNCTION IN SEPSIS: AN UPDATED NARRATIVE REVIEW

ABSTRACT

Sepsis is a multisystem disease process, which constitutes a significant public health challenge and is associated with high morbidity and mortality. Among other systems, sepsis is known to affect the cardiovascular system, which may manifest as myocardial injury, arrhythmias, refractory shock, and/or septic cardiomyopathy. Septic cardiomyopathy is defined as the reversible systolic and/or diastolic dysfunction of one or both ventricles. Left ventricle dysfunction has been extensively studied in the past, and its prognostic role in patients with sepsis is well documented. However, there is relatively scarce literature on right ventricle (RV) dysfunction and its role. Given the importance of timely detection of septic cardiomyopathy and its bearing on prognosis of patients, the role of RV dysfunction has come into renewed focus. Hence, through this review, we sought to describe the pathophysiology of RV dysfunction in sepsis and what have we learnt so far about its multifactorial nature. We also elucidate the roles of different biomarkers for its detection and prognosis, along with appropriate management of such patient population.

Management of Cardiogenic Shock Unrelated to Acute Myocardial Infarction

Cardiogenic shock is an extreme manifestation of acute decompensated heart failure. Cardiogenic shock is often caused by-and has traditionally been studied in the setting of-acute myocardial infarction (AMI CS); however, there is increasing incidence and recognition of cardiogenic shock not associated with acute myocardial infarction (non-AMI CS) as a distinct entity. Despite decades of study and technologic advancements, cardiogenic shock mortality remains as high as 50%, regardless of etiology. New approaches to shock phenotyping and classification have emerged, with a focus on appropriately matching patient physiology to a growing list of available interventions. Further study is needed to determine whether these efforts will lead to more nuanced use of mechanical circulatory support and improved patient outcomes, especially in non-AMI CS. In the meantime, models of care incorporating multidisciplinary decision making, such as shock teams, may improve patient selection and outcomes.

Liberation From Mechanical Ventilation in the Cardiac Intensive Care Unit

The prevalence of respiratory failure is increasing in the contemporary cardiac intensive care unit (CICU) and is associated with a significant increase in morbidity and mortality. For patients that survive their initial respiratory decompensation, liberation from invasive mechanical ventilation (IMV) and the decision to extubate requires careful clinical assessment and planning. Therefore, it is essential for the CICU clinician to know how to assess and manage the various stages of IMV liberation, including ventilator weaning, evaluation of extubation readiness, and provide post-extubation care. In this review, we provide a comprehensive approach to liberation from IMV in the CICU, including cardiopulmonary interactions relative to withdrawal from positive pressure ventilation, evaluation of readiness for and assessment of spontaneous breathing trials, sedation management to optimize extubation, strategies for patients at a high risk for extubation failure, and tracheostomy in the cardiovascular patient.

Critical Care Cardiology Trials Network (CCCTN): a cohort profile

AIMS

The aims of the Critical Care Cardiology Trials Network (CCCTN) are to develop a registry to investigate the epidemiology of cardiac critical illness and to establish a multicentre research network to conduct randomised clinical trials (RCTs) in patients with cardiac critical illness.

METHODS AND RESULTS

The CCCTN was founded in 2017 with 16 centres and has grown to a research network of over 40 academic and clinical centres in the United States and Canada. Each centre enters data for consecutive cardiac intensive care unit (CICU) admissions for at least 2 months of each calendar year. More than 20 000 unique CICU admissions are now included in the CCCTN Registry. To date, scientific observations from the CCCTN Registry include description of variations in care, the epidemiology and outcomes of all CICU patients, as well as subsets of patients with specific disease states, such as shock, heart failure, renal dysfunction, and respiratory failure. The CCCTN has also characterised utilization patterns, including use of mechanical circulatory support in response to changes in the heart transplantation allocation system, and the use and impact of multidisciplinary shock teams. Over years of multicentre collaboration, the CCCTN has established a robust research network to facilitate multicentre registry-based randomised trials in patients with cardiac critical illness.

CONCLUSION

The CCCTN is a large, prospective registry dedicated to describing processes-of-care and expanding clinical knowledge in cardiac critical illness. The CCCTN will serve as an investigational platform from which to conduct randomised controlled trials in this important patient population.

Outcomes of Patients With Primary Cardiac Diagnoses Admitted to Cardiac vs Noncardiac Intensive Care Units

BACKGROUND

Demographics in cardiac intensive care units (CICUs) have evolved, with increased prevalence of noncardiac critical illnesses.

OBJECTIVES

This study compares outcomes of patients with primary cardiac diagnoses admitted to CICUs vs those of patients with primary cardiac diagnoses admitted to noncardiac ICUs.

METHODS

The Cerner Health Facts Database was queried to identify adults with primary cardiac diagnoses admitted to ICUs within 48 hours of presentation between 2009 and 2014. Only hospitals with multiple ICUs including a CICU were studied. Information on ICU staffing was not available. A univariate analysis of ICU type (model 1) and multivariate analyses incorporating patient- and hospital-level variables (model 2) and concurrent, noncardiac, ICU-level diagnoses (model 3) were utilized to assess the impact of ICU type on inpatient mortality.

RESULTS

Of 16,163 encounters across 14 hospitals, 8,499 (52.6%) were admitted to CICUs and 7,664 (47.4%) to noncardiac ICUs. Univariate analysis (model 1) demonstrated increased mortality in noncardiac ICUs compared to CICUs (odds ratio [OR]: 1.47, 95% CI: 1.32-1.64; P < 0.0001). This risk dissipated (OR: 1.04, 95% CI: 0.91-1.18; P = 0.56) after controlling for patient- and hospital-level variables (model 2). Inclusion of concurrent, noncardiac, ICU-level diagnoses (model 3) lead to a reversal with decreased mortality in noncardiac ICUs (OR: 0.86, 95% CI: 0.76-0.98; P = 0.03).

CONCLUSIONS

In this historical cohort study evaluating CICU outcomes prior to the evolution of proposed staffing and care model modernization, survival of cardiac patients with concurrent, noncardiac critical illnesses may have been better with the expertise available in general system ICUs. These results may support contemporary efforts to increase the capacity to manage noncardiac critical illnesses in CICUs.

Relation of Ischemic Heart Disease to Outcomes in Patients With Acute Respiratory Distress Syndrome

Patients with ischemic heart disease (IHD) are often excluded from acute respiratory distress syndrome (ARDS) clinical trials. As a result, little is known about the impact of IHD in this population. We sought to assess the association between IHD and clinical outcomes in patients with ARDS. Participants from 4 ARDS randomized controlled trials with shared study criteria, definitions, and end points were included. Using multivariable logistic regression, we assessed for the association between IHD and a primary outcome of 60-day mortality. Secondary outcomes included 90-day mortality, 28-day ventilator-free days, and 28-day organ failure. Among 1,909 patients, 102 had a history of IHD (5.4%). Patients with IHD were more likely to be older and male (p <0.05). Noncardiac co-morbidities, severity of illness, and other markers of ARDS severity were not statistically different (all, p >0.05). Patients with IHD had a higher 60-day (39.2% vs 23.3%, p <0.001) and 90-day (40.2% vs 24.0%, p <0.001) mortality, and experienced more frequent renal (45.1% vs 32.0%, p = 0.006) and hepatic (35.3% vs 25.2%, p = 0.023) failure. After multivariable adjustment, 60-day (odds ratio [OR] 1.76; 95% confidence interval [CI]: 1.07 to 2.89, p = 0.025) and 90-day (OR 1.74; 95% CI: 1.06 to 2.85, p = 0.028) mortality remained higher. IHD was associated with 10% fewer ventilator-free days (incidence rate ratio 0.90; 95% CI: 0.85 to 0.96, p = 0.001). In conclusion, co-morbid IHD was associated with higher mortality and fewer ventilator-free days in patients with ARDS. Future studies are needed to identify predictors of mortality and improve treatment paradigms in this critically ill subgroup of patients.

Oxygen Supplementation and Hyperoxia in Critically Ill Cardiac Patients: From Pathophysiology to Clinical Practice

Oxygen supplementation has been a mainstay in the management of patients with acute cardiac disease. While hypoxia is known to be detrimental, the adverse effects of artificially high oxygen levels (hyperoxia) have only recently been recognized. Hyperoxia may induce harmful hemodynamic effects, including peripheral and coronary vasoconstriction, and direct cellular toxicity through the production of reactive oxygen species. In addition, emerging evidence has shown that hyperoxia is associated with adverse clinical outcomes. Thus, it is essential for the cardiac intensive care unit (CICU) clinician to understand the available evidence and titrate oxygen therapies to specific goals. This review summarizes the pathophysiology of oxygen within the cardiovascular system and the association between supplemental oxygen and hyperoxia in patients with common CICU diagnoses, including acute myocardial infarction, heart failure, shock, cardiac arrest, pulmonary hypertension, and respiratory failure. Finally, we highlight lessons learned from available trials, gaps in knowledge, and future directions.

Staffing models in the cardiac intensive care unit

PURPOSE OF REVIEW

The modern cardiac intensive care unit (CICU) has evolved into a high-intensity unit that cares for critically ill patients. Despite this transformation, changes to the staffing model and organizational structure in these specialized units have only recently begun to meet these challenges. We describe the most recent evidence which will inform future CICU staffing models.

RECENT FINDINGS

In the United States, the majority of CICUs are open as opposed to closed units, yet recent data suggests that transition to a closed staffing model is associated with a decrease in mortality. These reductions in mortality in closed CICUs are most pronounced in the most critically ill populations, such as patients with mechanical circulatory support, cardiac arrest, and respiratory failure. In addition, one study has shown that transition to a cardiac intensivist staffed CICU was associated with a reduction in mortality. Finally, multidisciplinary and protocolized teams imbedded within the CICU, specifically 'shock teams,' have recently been developed and may reduce mortality in this particularly sick patient population.

SUMMARY

Although the preponderance of data suggests improved outcomes with a closed, intensivist staffed CICU model, future multicenter studies are needed to better define the ideal staffing models for the contemporary CICU.

Quality of Heart Failure Care in the Intensive Care Unit

Patients with heart failure (HF) who are seen in an intensive care unit (ICU) manifest the highest-risk, most complex and most resource-intensive disease states. These patients account for a large relative proportion of days spent in an ICU. The paradigms by which critical care is provided to patients with HF are being reconsidered, including consideration of various multidisciplinary ICU staffing models and the development of acute-response teams. Traditional HF quality initiatives have centered on the peri- and postdischarge period in attempts to improve adherence to guideline-directed therapies and reduce readmissions. There is a compelling rationale for expanding high-quality efforts in treating patients with HF who are receiving critical care so we can improve outcomes, reduce preventable harm, improve teamwork and resource use, and achieve high health-system performance. Our goal is to answer the following question: For a patient with HF in the ICU, what is required for the provision of high-quality care? Herein, we first review the epidemiology of HF syndromes in the ICU and identify relevant critical care and quality stakeholders in HF. We next discuss the tenets of high-quality care for patients with HF in the ICU that will optimize critical care outcomes, such as ICU staffing models and evidence-based management of cardiac and noncardiac disease. We discuss strategies to mitigate preventable harm, improve ICU culture and conduct outcomes review, and we conclude with our summative vision of high-quality of ICU care for patients with HF; our vision includes clinical excellence, teamwork and ICU culture.

The association between cardiac intensive care unit mechanical ventilation volumes and in-hospital mortality

AIMS

The incidence of respiratory failure and use of invasive or non-invasive mechanical ventilation (MV) in the cardiac intensive care units (CICUs) is increasing. While institutional MV volumes are associated with reduced mortality in medical and surgical ICUs, this volume-mortality relationship has not been characterized in the CICU.

METHODS AND RESULTS

National population-based data were used to identify patients admitted to CICUs (2005-2015) requiring MV in Canada. CICUs were categorized into low (≤100), intermediate (101-300), and high (>300) volume centres based on spline knots identified in the association between annual MV volume and mortality. Outcomes of interest included all-cause in-hospital mortality, the proportion of patients requiring prolonged MV (>96 h) and CICU length of stay (LOS). Among 47 173 CICU admissions requiring MV, 89.5% (42 200) required invasive MV. The median annual CICU MV volume was 43 (inter-hospital range 1-490). Compared to low-volume centres (35.9%), in-hospital mortality was lower in intermediate [29.2%, adjusted odds ratio (aOR) 0.84, 95% confidence interval (CI) 0.72-0.97, P = 0.019] and high-volume (18.2%; aOR 0.82, 95% CI 0.66-1.02, P = 0.076) centres. Prolonged MV was higher in low-volume (29.2%) compared to high-volume (14.8%, aOR 0.70, 95% CI 0.55-0.89, P = 0.003) and intermediate-volume (23.0%, aOR 0.85, 95% CI 0.68-1.06, P = 0.14] centres. Mortality and prolonged MV were lower in percutaneous coronary intervention (PCI)-capable and academic centres, but a shorter CICU LOS was observed only in subgroup of PCI-capable intermediate- and high-volume hospitals.

CONCLUSIONS

In a national dataset, we observed that higher CICU MV volumes were associated with lower incidence of in-hospital mortality, prolonged MV, and CICU LOS. Our data highlight the need for minimum MV volume benchmarks for CICUs caring for patients with respiratory failure.

Epidemiology and causes of cardiogenic shock

PURPOSE OF REVIEW

Cardiogenic shock is a complex clinical syndrome of end-organ hypoperfusion due to impaired cardiac performance. Although cardiogenic shock has traditionally been viewed as a monolithic disorder predominantly caused by severe left ventricular dysfunction complicating acute myocardial infarction (AMI), there is increasing recognition of the diverse causes of cardiogenic shock and wide spectrum of clinical severity. The purpose of this review is to describe the contemporary epidemiology of cardiogenic shock, including trends in clinical outcomes and recent efforts to refine risk assessment.

RECENT FINDINGS

The incidence of cardiogenic shock among patients with AMI has remained remarkably stable at 3-10%; however, the proportion of cardiogenic shock cases related to AMI has decreased over time to ∼30%, while the proportion of cardiogenic shock cases due to acute decompensated heart failure has steadily increased. Estimated in-hospital mortality from cardiogenic shock in contemporary registries is approximately 30-40%, suggesting modest improvement in cardiogenic shock outcomes over the last decade. There is a wide spectrum of clinical severity among patients presenting with cardiogenic shock, which is described by the Society for Cardiovascular Angiography and Interventions clinical staging criteria.

SUMMARY

Improved clinical characterization and risk assessment of patients with cardiogenic shock may facilitate more effective clinical investigations of this morbid clinical syndrome.

Trends in Therapy and Outcomes Associated With Respiratory Failure in Patients Admitted to the Cardiac Intensive Care Unit

PURPOSE

To describe the epidemiology, outcomes, and temporal trends of respiratory failure in the cardiac intensive care unit (CICU).

MATERIALS AND METHODS

Retrospective cohort analysis of 2,986 unique Mayo Clinic CICU patients from 2007 to 2018 with respiratory failure. Temporal trends were analyzed, along with hospital and 1-year mortality. Multivariable logistic regression was used to determine adjusted hospital mortality trends.

RESULTS

The prevalence of respiratory failure in the CICU increased from 15% to 38% during the study period (P < 0.001 for trend). Among patients with respiratory failure, the utilization of invasive ventilation decreased and noninvasive ventilation modalities increased over time. Hospital mortality and 1-year mortality were 24% and 54%, respectively, with variation according to the type of respiratory support (highest among patients receiving invasive ventilation alone: 35% and 46%, respectively). Hospital mortality was highest among patients with concomitant cardiac arrest and/or shock (52% for patients with both). Hospital mortality decreased in the overall population from 35% to 25% (P < 0.001 for trend), but was unchanged among patients receiving positive-pressure ventilation.

CONCLUSIONS

The prevalence of respiratory failure in CICU more than doubled during the last decade. The use of noninvasive respiratory support increased, while overall mortality declined over time. Cardiac arrest and shock accounted for the majority of deaths. Further research is needed to optimize the outcomes of high-risk CICU patients with respiratory failure.

Association between Respiratory Failure and Clinical Outcomes in Patients with Acute Heart Failure: Analysis of 5 Pooled Clinical Trials

BACKGROUND

Despite a temporal increase in respiratory failure in patients hospitalized with acute heart failure (HF), clinical trials have largely not reported the incidence or associated clinical outcomes for patients requiring mechanical ventilation.

METHODS AND RESULTS

After pooling 5 acute HF clinical trials, we used multivariable logistic regression adjusted for demographics, comorbidities, examinations, and laboratory findings to assess associations between mechanical ventilation and clinical outcomes. Among the 8296 patients, 210 (2.5%) required mechanical ventilation. Age, sex, smoking history, baseline ejection fraction, HF etiology, and the proportion of patients randomized to treatment or placebo in the original clinical trial were similar between groups (all, P > 0.05). Baseline diabetes mellitus was more common in the mechanical ventilation group (P = 0.02), but other comorbidities, including chronic lung disease, were otherwise similar (all P > 0.05). HF rehospitalization at 30 days (12.7% vs 6.6%, P < 0.001) and all-cause 60-day mortality (33.3% vs 6.1%, P < 0.001) was higher among patients requiring mechanical ventilation. After multivariable adjustment, mechanical ventilation use was associated with an increased 30-day HF rehospitalization (odds ratio 2.03; 95% confidence interval, 1.29-3.21, P = 0.002), 30-day mortality (odds ratio 10.40; 95% confidence interval, 7.22-14.98, P < 0.001), and 60-day mortality (odds ratio 7.68; 95% confidence interval, 5.50-10.74, P < 0.001). The influence of mechanical ventilation did not differ by HF etiology or baseline ejection fraction (both, interaction P > 0.20).

CONCLUSIONS

Respiratory failure during an index hospitalization for acute HF was associated with increased rehospitalization and all-cause mortality. The development of respiratory failure during an acute HF admission identifies a particularly vulnerable population, which should be identified for closer monitoring.