Flow-Sizing Critical Care Resources.

OBJECTIVES: To describe the factors affecting critical care capacity and how critical care organizations (CCOs) within academic centers in the U.S. flow-size critical care resources under normal operations, strain, and surge conditions. DATA SOURCES: PubMed, federal agency and American Hospital Association reports, and previous CCO survey results were reviewed. STUDY SELECTION: Studies and reports of critical care bed capacity and utilization within CCOs and in the United States were selected. DATA EXTRACTION: The Academic Leaders in the Critical Care Medicine Task Force established regular conference calls to reach a consensus on the approach of CCOs to "flow-sizing" critical care services. DATA SYNTHESIS: The approach of CCOs to "flow-sizing" critical care is outlined. The vertical (relation to institutional resources, e.g., space allocation, equipment, personnel redistribution) and horizontal (interdepartmental, e.g., emergency department, operating room, inpatient floors) integration of critical care delivery (ICUs, rapid response) for healthcare organizations and the methods by which CCOs flow-size critical care during normal operations, strain, and surge conditions are described. The advantages, barriers, and recommendations for the rapid and efficient scaling of critical care operations via a CCO structure are explained. Comprehensive guidance and resources for the development of "flow-sizing" capability by a CCO within a healthcare organization are provided. CONCLUSIONS: We identified and summarized the fundamental principles affecting critical care capacity. The taskforce highlighted the advantages of the CCO governance model to achieve rapid and cost-effective "flow-sizing" of critical care services and provide recommendations and resources to facilitate this capability. The relevance of a comprehensive approach to "flow-sizing" has become particularly relevant in the wake of the latest COVID-19 pandemic. In light of the growing risks of another extreme epidemic, planning for adequate capacity to confront the next critical care crisis is urgent.

A Randomized Double-Blinded Placebo Controlled Trial of Clazakizumab for the Treatment of COVID-19 Pneumonia With Hyperinflammation.

OBJECTIVES: We designed this study to test whether clazakizumab, a direct interleukin-6 inhibitor, benefits patients hospitalized with severe or critical COVID-19 disease accompanied by hyperinflammation. DESIGN: Multicenter, randomized, double-blinded, placebo-controlled, seamless phase II/III trial. SETTING: Five U.S. medical centers. PATIENTS: Adults inpatients with severe COVID-19 disease and hyperinflammation. INTERVENTIONS: Eighty-one patients enrolled in phase II, randomized 1:1:1 to low-dose (12.5 mg) or high-dose (25 mg) clazakizumab or placebo. Ninety-seven patients enrolled in phase III, randomized 1:1 to high-dose clazakizumab or placebo. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 28-day ventilator-free survival. Secondary outcomes included overall survival, frequency and duration of intubation, and frequency and duration of ICU admission. Per Data Safety and Monitoring Board recommendations, additional secondary outcomes describing clinical status and status changes, as measured by an ordinal scale, were added. Bayesian cumulative proportional odds, logistic, and Poisson regression models were used. The low-dose arm was dropped when the phase II study suggested superiority of the high-dose arm. We report on 152 patients, 74 randomized to placebo and 78 to high-dose clazakizumab. Patients receiving clazakizumab had greater odds of 28-day ventilator-free survival (odds ratio [OR] = 3.84; p [OR > 1] 99.9%), as well as overall survival at 28 and 60 days (OR = 1.75; p [OR > 1] 86.5% and OR = 2.53; p [OR > 1] 97.7%). Clazakizumab was associated with lower odds of intubation (OR = 0.2; p [OR] < 1; 99.9%) and ICU admission (OR = 0.26; p [OR < 1] 99.6%); shorter durations of ventilation and ICU stay (risk ratio [RR] < 0.75; p [RR < 1] > 99% for both); and greater odds of improved clinical status at 14, 28, and 60 days (OR = 2.32, p [OR > 1] 98.1%; OR = 3.36, p [OR > 1] 99.6%; and OR = 3.52, p [OR > 1] 99.8%, respectively). CONCLUSIONS: Clazakizumab significantly improved 28-day ventilator-free survival, 28- and 60-day overall survival, as well as clinical outcomes in hospitalized patients with COVID-19 and hyperinflammation.

First Use of a Novel Extracorporeal Life Support System: Successful Application in Tracheoesophageal Fistula Repair.

Extracorporeal life support, commonly referred to as extracorporeal membrane oxygenation (ECMO), is indicated when conventional medical and surgical measures fail to support a patient during cardiac or respiratory failure. Increased use of ECMO in recent years has led to innovation that has improved safety in appropriate candidates. This has resulted in the application of novel approaches to complex surgical problems. Herein, we describe a simple, novel, and new-to-market ECMO circuit used for successful perioperative veno-venous ECMO support of a patient undergoing complex repair of a tracheoesophageal fistula. We believe that this circuit and its use for intra-and post-operative extracorporeal support provides a framework for safe and simple ECMO support in the future, including perioperative support for patients undergoing complicated and challenging thoracic procedures.

Risk Factors for and Outcomes Associated With Peri-Intubation Hypoxemia: A Multicenter Prospective Cohort Study.

BACKGROUND: Little is known about hypoxemia surrounding endotracheal intubation in the critically ill. Thus, we sought to identify risk factors associated with peri-intubation hypoxemia and its effects' on the critically ill. METHODS: Data from a multicenter, prospective, cohort study enrolling 1,033 critically ill adults who underwent endotracheal intubation across 16 medical/surgical ICUs in the United States from July 2015-January 2017 were used to identify risk factors associated with peri-intubation hypoxemia and its effects on patient outcomes. We defined hypoxemia as any pulse oximetry ≤ 88% during and up to 30 minutes following endotracheal intubation. RESULTS: In the full analysis (n = 1,033), 123 (11.9%) patients experienced the primary outcome. Five risk factors independently associated with our outcome were identified on multiple logistic regression: cardiac related reason for endotracheal intubation (OR 1.67, [95% CI 1.04, 2.69]); pre-intubation noninvasive ventilation (OR 1.66, [95% CI 1.09, 2.54]); emergency intubation (OR 1.65, [95% CI 1.06, 2.55]); moderate-severe difficult bag-mask ventilation (OR 2.68, [95% CI 1.72, 4.19]); and crystalloid administration within the preceding 24 hours (OR 1.24, [95% CI 1.07, 1.45]; per liter up to 4 liters). Higher baseline SpO2 was found to be protective (OR 0.93, [95% CI 0.91, 0.96]; per percent up to 97%). Consistent results were seen in a separate analysis on only stable patients (n = 921, 93 [10.1%]) (those without baseline hypoxemia ≤ 88%). Peri-intubation hypoxemia was associated with in-hospital mortality (OR 2.40, [95% CI 1.33, 4.31]; stable patients: OR 2.67, [95% CI 1.38, 5.17]) but not ICU length of stay (point estimate 0.9 days, [95% CI -1.0, 2.8 days]; stable patients: point estimate 1.5 days, [95% CI -0.4, 3.4 days]) after adjusting for age, body mass index, illness severity, airway related reason for intubation (i.e., acute respiratory failure), and baseline SPO2. CONCLUSIONS: Patients with pre-existing noninvasive ventilation and volume loading who were intubated emergently in the setting of hemodynamic compromise with bag-mask ventilation described as moderate-severe were at increased risk for peri-intubation hypoxemia. Higher baseline oxygenation was found to be protective against peri-intubation hypoxemia. Peri-intubation hypoxemia was associated with in-hospital mortality but not ICU length of stay. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02508948 and Registered Report Identifier: RR2-10.2196/11101.

Reversible cardiac dysfunction in severe COVID-19 infection, mechanisms and case report.

A previously healthy 49-year-old male patient presented with COVID-19 infection and required mechanical ventilation and extracorporeal membrane oxygenation due to severe hypoxemia. Echocardiography showed cardiac dysfunction with an apical sparing strain pattern, which rapidly normalized within a week. Apical sparing myocardial strain in patients with COVID-19 infection may suggest reverse-type stress cardiomyopathy.

Effect of Ascorbic Acid, Corticosteroids, and Thiamine on Organ Injury in Septic Shock: The ACTS Randomized Clinical Trial.

IMPORTANCE: The combination of ascorbic acid, corticosteroids, and thiamine has been identified as a potential therapy for septic shock. OBJECTIVE: To determine whether the combination of ascorbic acid, corticosteroids, and thiamine attenuates organ injury in patients with septic shock. DESIGN, SETTING, AND PARTICIPANTS: Randomized, blinded, multicenter clinical trial of ascorbic acid, corticosteroids, and thiamine vs placebo for adult patients with septic shock. Two hundred five patients were enrolled between February 9, 2018, and October 27, 2019, at 14 centers in the United States. Follow-up continued until November 26, 2019. INTERVENTIONS: Patients were randomly assigned to receive parenteral ascorbic acid (1500 mg), hydrocortisone (50 mg), and thiamine (100 mg) every 6 hours for 4 days (n = 103) or placebo in matching volumes at the same time points (n = 102). MAIN OUTCOMES AND MEASURES: The primary outcome was change in the Sequential Organ Failure Assessment (SOFA) score (range, 0-24; 0 = best) between enrollment and 72 hours. Key secondary outcomes included kidney failure and 30-day mortality. Patients who received at least 1 dose of study drug were included in analyses. RESULTS: Among 205 randomized patients (mean age, 68 [SD, 15] years; 90 [44%] women), 200 (98%) received at least 1 dose of study drug, completed the trial, and were included in the analyses (101 with intervention and 99 with placebo group). Overall, there was no statistically significant interaction between time and treatment group with regard to SOFA score over the 72 hours after enrollment (mean SOFA score change from 9.1 to 4.4 [-4.7] points with intervention vs 9.2 to 5.1 [-4.1] points with placebo; adjusted mean difference, -0.8; 95% CI, -1.7 to 0.2; P = .12 for interaction). There was no statistically significant difference in the incidence of kidney failure (31.7% with intervention vs 27.3% with placebo; adjusted risk difference, 0.03; 95% CI, -0.1 to 0.2; P = .58) or in 30-day mortality (34.7% vs 29.3%, respectively; hazard ratio, 1.3; 95% CI, 0.8-2.2; P = .26). The most common serious adverse events were hyperglycemia (12 patients with intervention and 7 patients with placebo), hypernatremia (11 and 7 patients, respectively), and new hospital-acquired infection (13 and 12 patients, respectively). CONCLUSIONS AND RELEVANCE: In patients with septic shock, the combination of ascorbic acid, corticosteroids, and thiamine, compared with placebo, did not result in a statistically significant reduction in SOFA score during the first 72 hours after enrollment. These data do not support routine use of this combination therapy for patients with septic shock. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03389555.

Ascorbic acid, corticosteroids, and thiamine in sepsis: a review of the biologic rationale and the present state of clinical evaluation.

The combination of thiamine, ascorbic acid, and hydrocortisone has recently emerged as a potential adjunctive therapy to antibiotics, infectious source control, and supportive care for patients with sepsis and septic shock. In the present manuscript, we provide a comprehensive review of the pathophysiologic basis and supporting research for each element of the thiamine, ascorbic acid, and hydrocortisone drug combination in sepsis. In addition, we describe potential areas of synergy between these therapies and discuss the strengths/weaknesses of the two studies to date which have evaluated the drug combination in patients with severe infection. Finally, we describe the current state of current clinical practice as it relates to the thiamine, ascorbic acid, and hydrocortisone combination and present an overview of the randomized, placebo-controlled, multi-center Ascorbic acid, Corticosteroids, and Thiamine in Sepsis (ACTS) trial and other planned/ongoing randomized clinical trials.

Ultrasound-Enabled Noninvasive Management of Inadvertent Carotid Cannulation.

INTRODUCTION: Despite ultrasound use, accidental carotid cannulation is possible during placement of a central venous catheter (CVC), requiring operative repair of the carotid artery and removal of the catheter. CASE PRESENTATION: We report 2 cases-a 59-year-old Hispanic man and an 86-year-old white man-of inadvertent placement of a CVC into the left common carotid artery, removed via a pull-and-pressure technique under real-time ultrasound guidance. No complications occurred and follow-up imaging was negative for fistula creation, hematoma, or cerebral infarcts. DISCUSSION: Prior cases have reported accidental carotid cannulations that required operative repair. Our discussion focuses on the complications of removal of CVCs from the common carotid, and the utility, feasibility, and safety of using real-time ultrasound guidance in the removal. CONCLUSION: While operative removal of CVCs accidentally placed in the carotid is recommended, an ultrasound-enabled pull-and-pressure technique may prevent complications and avoid need for surgical repair in critically ill patients.

Chloride Content of Fluids Used for Large-Volume Resuscitation Is Associated With Reduced Survival.

OBJECTIVE: We sought to investigate if the chloride content of fluids used in resuscitation was associated with short- and long-term outcomes. DESIGN: We identified patients who received large-volume fluid resuscitation, defined as greater than 60 mL/kg over a 24-hour period. Chloride load was determined for each patient based on the chloride ion concentration of the fluids they received during large-volume fluid resuscitation multiplied by the volume of fluids. We compared the development of hyperchloremic acidosis, acute kidney injury, and survival among those with higher and lower chloride loads. SETTING: University Medical Center. PATIENTS: Patients admitted to ICUs from 2000 to 2008. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among 4,710 patients receiving large-volume fluid resuscitation, hyperchloremic acidosis was documented in 523 (11%). Crude rates of hyperchloremic acidosis, acute kidney injury, and hospital mortality all increased significantly as chloride load increased (p < 0.001). However, chloride load was no longer associated with hyperchloremic acidosis or acute kidney injury after controlling for total fluids, age, and baseline severity. Conversely, each 100 mEq increase in chloride load was associated with a 5.5% increase in the hazard of death even after controlling for total fluid volume, age, and severity (p = 0.0015) over 1 year. CONCLUSIONS: Chloride load is associated with significant adverse effects on survival out to 1 year even after controlling for total fluid load, age, and baseline severity of illness. However, the relationship between chloride load and development of hyperchloremic acidosis or acute kidney injury is less clear, and further research is needed to elucidate the mechanisms underlying the adverse effects of chloride load on survival.

Mechanical circulatory assist devices: a primer for critical care and emergency physicians.

Mechanical circulatory assist devices are now commonly used in the treatment of severe heart failure as bridges to cardiac transplant, as destination therapy for patients who are not transplant candidates, and as bridges to recovery and "decision-making". These devices, which can be used to support the left or right ventricles or both, restore circulation to the tissues, thereby improving organ function. Left ventricular assist devices (LVADs) are the most common support devices. To care for patients with these devices, health care providers in emergency departments (EDs) and intensive care units (ICUs) need to understand the physiology of the devices, the vocabulary of mechanical support, the types of complications patients may have, diagnostic techniques, and decision-making regarding treatment. Patients with LVADs who come to the ED or are admitted to the ICU usually have nonspecific clinical symptoms, most commonly shortness of breath, hypotension, anemia, chest pain, syncope, hemoptysis, gastrointestinal bleeding, jaundice, fever, oliguria and hematuria, altered mental status, headache, seizure, and back pain. Other patients are seen for cardiac arrest, psychiatric issues, sequelae of noncardiac surgery, and trauma. Although most patients have LVADs, some may have biventricular support devices or total artificial hearts. Involving a team of cardiac surgeons, perfusion experts, and heart-failure physicians, as well as ED and ICU physicians and nurses, is critical for managing treatment for these patients and for successful outcomes. This review is designed for critical care providers who may be the first to see these patients in the ED or ICU.

Identification of dynamic prehospital changes with continuous vital signs acquisition.

OBJECTIVE: In most trauma registries, prehospital trauma data are often missing or unreliable because of the difficult dual task consigned to prehospital providers of recording vital signs and simultaneously resuscitating patients. The purpose of this study was to test the hypothesis that the analysis of continuous vital signs acquired automatically, without prehospital provider input, improves vital signs data quality, captures more extreme values that might be missed with conventional human data recording, and changes Trauma Injury Severity Scores compared with retrospectively compiled prehospital trauma registry data. METHODS: A statewide vital signs collection network in 6 medevac helicopters was deployed for prehospital vital signs acquisition using a locally built vital signs data recorder (VSDR) to capture continuous vital signs from the patient monitor onto a memory card. VSDR vital signs data were assessed by 3 raters, and intraclass correlation coefficients were calculated to test interrater reliability. Agreement between VSDR and trauma registry data was compared with the methods of Altman and Bland including corresponding calculations for precision and bias. RESULTS: Automated prehospital continuous VSDR data were collected in 177 patients. There was good agreement between the first recorded vital signs from the VSDR and the trauma registry value. Significant differences were observed between the highest and lowest heart rate, systolic blood pressure, and pulse oximeter from the VSDR and the trauma registry data (P< .001). Trauma Injury Severity Scores changed in 12 patients (7%) when using data from the VSDR. CONCLUSION: Real-time continuous vital signs monitoring and data acquisition can identify dynamic prehospital changes, which may be missed compared with vital signs recorded manually during distinct prehospital intervals. In the future, the use of automated vital signs trending may improve the quality of data reported for inclusion in trauma registries. These data may be used to develop improved triage algorithms aimed at optimizing resource use and enhancing patient outcomes.

Nurse-led medical emergency response reduces code blue team activations in non-hospitalized patients.

Objective: We describe the creation of a two-tier emergency response system with a nurse-led first responder program titled "MET-RN" (Medical Emergency Team-Registered Nurse) created for ambulatory settings supported by a critical care code blue team for escalation of care. This observational study evaluated the clinical characteristics and effects of a MET-RN program on the code blue response. Methods: A retrospective review of the MET-RN response data was assessed from January 2016 to June 2021. Data collected included time of call, call location, patient comorbidities, triage category (minor, urgent, or emergent), activation trigger, interventions performed, duration of the event, and patient disposition. In instances where the patient was admitted to the hospital, the discharge diagnosis and emergency department (ED) triage score were collected. Differences were tested using analysis of variance (ANOVA) F-tests, with Tukey post-hoc testing where applicable. Results: MET-RN responded to 6,564 encounters from January 2016 to June 2021. The most frequent trigger call was dizziness/lightheadedness, with a prevalence of 12.0%. 33.9% of the patients seen by MET-RN were transported to the ED for further evaluation. Establishing a MET-RN system led to an estimated median of 58.3% reduction in utilization of the code blue team per quarter. Conclusion: The creation of MET-RN first responder system enabled the ambulatory areas to receive minor, urgent, and emergent patient care support, leading to a decrease in utilization of the code blue team for the hospital. A two-tiered response system resulted in an improved allocation of hospital resources and kept critical care teams in high-acuity areas while maintaining patient safety.

Extracorporeal membrane oxygenation for general thoracic surgery: case series and narrative review.

Background and Objective: Extracorporeal membrane oxygenation (ECMO) has historically been utilized as a temporary life support option for patients with severe cardiac and pulmonary dysfunction. Recent advancements have enabled the safe application of ECMO in a wider variety of patients; we present a review of its use in patients undergoing general thoracic procedures supported by a case series at our institution. Methods: We review current literature focusing on ECMO applications in thoracic surgery outside of the traditional use. Additionally, we offer three cases of ECMO utilization to illustrate success stories and key lessons learned regarding the use of ECMO in general thoracic surgery. Key Content and Findings: Technologic advancements and enhanced safety profiles have enabled the safe application of ECMO in a wide array of patients far beyond the historic indications of cardiogenic shock and acute respiratory distress syndrome (ARDS). It is now feasible to consider ECMO for management of acute thoracic emergencies, as well as to better facilitate operative safety in complex general thoracic surgical procedures. Both venovenous and venoarterial ECMO can be utilized in carefully selected patients to provide cardiopulmonary support while enabling improved visualization and increased mobilization without concern for respiratory and/or cardiac compromise. Conclusions: Enthusiasm for the use of ECMO has increased in recent years. What was once considered a salvage therapy in cases of life-threatening cardiopulmonary decompensation now plays an increasingly important role in the safe conduct of complex thoracic surgery procedures, provides much needed time for organ recovery, and offers acute resuscitation options. This shift broadens our ability to deliver life-saving care to patients that previously would have otherwise had limited treatment options.

Towards evidence-based emergency medicine: best BETs from the Manchester Royal Infirmary. BET 1: Cricoid pressure in emergency rapid sequence induction.

A short-cut review was carried out to establish whether the application of cricoid pressure during the induction of general anaesthesia reduced the incidence of regurgitation and aspiration of gastric contents. One good quality review article, two studies and two abstracts provided the best evidence to answer the clinical question. The authors, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are tabulated (table 1). It is concluded that although there is a theoretical advantage to providing cricoid pressure during induction, there is little evidence of any benefit at this time.

Tracheostomy in high-risk patients on ECMO: A bedside hybrid dilational technique utilizing a Rummel tourniquet.

Objective: Traditionally, critically ill patients requiring prolonged mechanical ventilation benefit from a long-term airway, thus necessitating tracheostomy. The widespread application of extracorporeal membrane oxygenation (ECMO) has exponentially increased in recent years, creating a new subset of patients necessitating tracheostomy with significantly increased bleeding risk. We present a hybrid dilational tracheostomy technique utilizing a Rummel tourniquet developed at our institution to mitigate bleeding risk in patients on ECMO necessitating long-term airway. Methods: A total of 24 patients on ECMO underwent bedside hybrid dilational tracheostomy with utilization of a Rummel tourniquet from 06/2020 to 01/2022 at our institution. These patients were followed longitudinally and evaluated for postoperative bleeding. Particular attention was paid to anticoagulation regimens pre- and post-operatively. Results: The primary outcome of the study, postoperative bleeding, was observed in four of the 24 study participants (16.67 %). Each of these complications were managed with tightening of the Rummel tourniquet and application of hemostatic packing agents; no operative interventions were required. Anticoagulation was held for a mean time of 4.33 h preoperatively and 5.2 h postoperatively. Conclusions: Our data support this hybrid tracheostomy technique with the addition of a Rummel tourniquet to be a safe and effective adjunct for perioperative hemostasis in high-risk patients necessitating tracheostomy while on ECMO. While this technique was initially developed for critically ill COVID-19 patients, we believe it can be applied to all patients on ECMO to help mitigate perioperative bleeding risk.

Spontaneous middle lobe torsion: An institutional case series.

Objective: Lobar torsion is a rare occurrence in which a portion of the lung is twisted on its bronchovascular pedicle. The vast majority are observed in the acute postoperative period often following right upper lobectomy. Spontaneous middle lobe torsion independent of pulmonary resection is exceptionally rarer; fewer than 15 cases have been recorded. We present an institutional case series of 2 patients postorthotopic liver transplantation who developed spontaneous middle lobe torsion due to large pleural effusions. Methods: We provide the medical course as well as intraoperative techniques for our 2 patients along with a review of the literature. Results: Both patients in this case series underwent orthotopic liver transplant complicated postoperatively by a large pulmonary effusion. Patient one developed an abdominal hematoma requiring evacuation and repair, after which he developed progressive shortness of breath. Bronchoscopy revealed a right middle lobe obstruction; upon thoracotomy, 180-degree torsion with widespread necrosis was evident and the middle lobe was removed. He is doing well to date. Patient 2 experienced postoperative pleural effusion and mucus plugging; computed tomography revealed abrupt middle lobe arterial occlusion prompting urgent operative intervention. Again, the middle lobe was grossly ischemic and dissection revealed a 360-degree torsion around the pedicle. It was resected. He is doing well to date. Conclusions: As the result of its rarity, radiographic and clinical diagnosis of spontaneous pulmonary lobar torsion is challenging; a high index of suspicion for spontaneous middle lobe torsion must be maintained to avoid delays in diagnosis. Prompt surgical intervention is essential to improve patient outcomes.

Inferior vena cava assessment in the bedside diagnosis of acute heart failure.

OBJECTIVES: The objective of this study was to determine the test characteristics of the caval index and caval-aortic ratio in predicting the diagnosis of acute heart failure in patients with undifferentiated dyspnea in the emergency department (ED). METHODS: This prospective observational study was performed at an urban ED that enrolled patients, 50 years or older, with acute dyspnea. A sonographic caval index was calculated as the percentage decrease in the inferior vena cava (IVC) diameter during respiration. A caval-aortic ratio was defined by the maximum IVC diameter divided by the aortic diameter. The sensitivity, specificity, and likelihood ratios of these measurements associated with heart failure were estimated. RESULTS: Eighty-nine patients were enrolled in the study with a mean age of 68 years. A caval index of less than 33% had 80% sensitivity (95% confidence interval [CI], 63%-91%) and 81% specificity (95% CI, 68%-90%) in diagnosing acute heart failure, whereas an index of less than 15% had a 37% sensitivity (95% CI, 22%-55%) and 96% specificity (95% CI, 86%-99%). The sensitivity of a caval-aortic ratio of more than 1.2 was 33% (95% CI, 18%-52%) and the specificity was 96% (95% CI, 86%-99%). Positive likelihood ratios were 10 for a caval index of less than 15%, 4.3 for an index of less than 33%, and 8.3 for a caval-aortic ratio of more than 1.2. CONCLUSION: Bedside assessments of the caval index or caval-aortic ratio may be useful clinical adjuncts in establishing the diagnosis of acute heart failure in patients with undifferentiated dyspnea.