Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) occurs in up to 10% of patients with respiratory failure admitted through the emergency department. Use of noninvasive respiratory support has proliferated in recent years; clinicians must understand the relative merits and risks of these technologies and know how to recognize signs of failure. The cornerstone of ARDS care of the mechanically ventilated patient is low-tidal volume ventilation based on ideal body weight. Adjunctive therapies, such as prone positioning and neuromuscular blockade, may have a role in the emergency department management of ARDS depending on patient and department characteristics.

A primer for managing cardiac transplant patients in the emergency department setting.

BACKGROUND: Cardiac transplant is an effective long-term management option for several severe cardiac diseases. These cardiac transplant patients may present to the emergency department with a range of issues involving the cardiac transplantation, including complications due to their transplant as well as altered presentations of disease resulting from their transplant. OBJECTIVE: This narrative review provides a focused guide to the evaluation and management of patients with cardiac transplantation and its complications. DISCUSSION: Cardiac transplant is an effective therapy for end-stage heart failure. A transplanted heart varies both anatomically and physiologically from a native heart. Several significant complications may occur. Graft failure, rejection, and infection are common causes of morbidity and mortality within the first year of transplant. As these patients are on significant immunosuppressive medication regimens, they are at risk of infection, but inadequate immunosuppression increases the risk of acute rejection. A variety of dysrhythmias such as atrial fibrillation and ventricular dysrhythmias may occur. These patients are also at risk of acute coronary syndrome, cardiac allograft vasculopathy, and medication adverse events. Importantly, patients with acute coronary syndrome can have an altered presentation with the so-called "painless" myocardial infarction. Consultation with the transplant physician is recommended, if available, for these patients to assist in evaluation and management. CONCLUSIONS: An understanding of the presentations and various complications that may affect patients with cardiac transplant will assist emergency clinicians in the care of these patients.

Vital sign patterns before shock-related cardiopulmonary arrest.

OBJECTIVE: Traditional vital sign thresholds reflect an increased risk of mortality, which may occur hours, days, or weeks following illness/injury, limiting immediate clinical significance to guide rescue therapy to avoid arrest. Our objective is to explore vital sign patterns prior to arrest due to shock. DESIGN: This retrospective observational analysis utilized physiological data from adult helicopter patients suffering provider-witnessed arrest. Pre-arrest values for systolic blood pressure (SBP), mean arterial pressure (MAP), heart rate (HR), shock index, and end-tidal carbon dioxide (EtCO2) were modeled against time using polynomial linear regression. The "terminal inflection point" beyond which arrest was imminent was identified where slope equals 1.0 (shock index) or -1.0 (SBP, MAP, HR, EtCO2) and was then compared to initial values. SETTING: Air ambulance services. PATIENTS: 70 helicopter patients over age fourteen suffering cardiac arrest. RESULTS: SBP and MAP demonstrated a gentle decline followed by acceleration beyond the inflection point (SBP 80.7 mmHg, MAP 61.9 mmHg). HR demonstrated an increase followed by a terminal drop, but inflection point values fell within normal range. Shock index increased gradually from a mean of 0.9 to the inflection point of 1.1. Initial EtCO2 values declined gradually from normal (34.4 mmHg) to the inflection point (24.7 mmHg), then dropped precipitously into arrest. All inflection points occurred 2-5 min prior to arrest. CONCLUSIONS: Vital sign patterns were defined for SBP, MAP, HR, shock index, and EtCO2 with clear inflection points identified 2-5 min prior to arrest. These patterns may help guide therapy to reverse deterioration and prevent arrest.

Systolic Blood Pressure Threshold for HEMS-Witnessed Arrests.

OBJECTIVE: Defining vital sign thresholds has focused on mortality, which may be delayed for hours, days, or weeks after injury. This limits the immediate clinical significance in guiding therapy to avoid arrest. The aim of this study was to identify a systolic blood pressure (SBP) threshold indicating imminent cardiopulmonary arrest. METHODS: This was a retrospective, observational study analyzing physiological data from air medical patients suffering witnessed arrest. We limited the analysis to a subgroup of adult (> 14 years) patients with hypoperfusion-related arrest. Prearrest SBP values were plotted over time, with arrest defined as "time zero." Multiple linear regression was used to define a best fit curve to identify an inflection point beyond which arrest was imminent. RESULTS: A total of 53 eligible patients were identified; 33 (62%) were trauma victims. A fifth-degree equation showed appropriate goodness of fit (r = -.66, P < .0001). An inflection point was identified at an SBP of 78 mm Hg, with arrest occurring approximately 3 minutes later. CONCLUSION: An inflection point below SBP 80 mm Hg was identified, suggesting a predictable physiological pattern for perfusion-related deterioration. This may help guide therapy to reverse deterioration and prevent arrest.