Douglas S. Ander

Undetected cardiogenic shock in patients with congestive heart failure presenting to the emergency department

The purpose of this study was to examine the use of lactic acid levels and continuous central venous oxygen saturation (central venous oximetry) to stratify and treat patients with acutely decompensated end-stage chronic congestive heart failure (CHF) presenting to the emergency department. This prospective, convenience, non-outcome study was performed at an urban tertiary care hospital. Patients with end-stage CHF with an ejection fraction <30% presenting in decompensated CHF were eligible for the study. Patients were assessed using the Killip classification and New York Heart Association criteria. After lactic acid levels were obtained, patients were managed according to a standardized protocol guided by central venous oximetry. The patients were divided into high lactic acid (n = 22), low lactic acid (n = 5), and control groups (stable patients presenting to a cardiology clinic, n = 17) for comparison. There was no statistical difference in vital signs, or Killip and New York Heart Association criteria among the 3 groups. Central venous oxygen saturation was significantly lower in the high lactic acid group (32 +/- 12%) than in the normal lactic acid (51 +/- 13%) and control groups (60 +/- 6%) (p < 0.001). After treatment there was a significant decrease in lactic acid (-3.65 +/- 3.65 mM/L) and an increase in central venous oxygen saturation (32 +/- 13%) in the high lactic acid group compared with the normal lactic acid group (p < 0.001). A significant subset of patients with decompensated end-stage CHF present to the emergency department in occult shock and are clinically indistinguishable from patients with mildly decompensated CHF and stable CHF. Once identified, these patients require aggressive alternative management and disposition. Further study is necessary to identify whether this intervention impacts morbidity, mortality, and health care resource consumption.

Society of Chest Pain Centers recommendations for the evaluation and management of the observation stay acute heart failure patient-parts 1-6.

Making the definitive diagnosis of heart failure in the acute care setting can be difficult. In the emergency department this needs to be done rapidly, frequently, and accurately, without access to a patient’s health records and while simultaneously initiating the appropriate diagnostic and therapeutic interventions. This section reviews the diagnostic strategies available to the physician confronted with a patient in whom the differential diagnosis includes acute heart failure. (Crit Pathways in Cardiol 2008;7: 91–95) Making the Diagnosis of Heart Failure When Patients Present With Symptoms Possibly Related to Acute Heart Failure Making the definitive diagnosis of heart failure (HF) in the acute care setting can be difficult. In the emergency department (ED) this needs to be done rapidly, frequently without access to a patient’s health records while simultaneously initiating the appropriate diagnostic and therapeutic interventions. The physician must determine the etiology of symptoms in patients with suspected HF based on the initial history, physical examination, diagnostic studies (laboratory data, electrocardiogram, and radiography), as well as response to empiric therapy. PubMed was searched in a systematic manner using a combination of search terms relevant to each topic specific to early diagnosis available in the emergency department setting. References from articles and guidelines so identified were also evaluated for additional pertinent literature. The Initial History and Physical Examination The most common symptom of HF is dyspnea. However, dyspnea is also common in the general population. Even in well persons, a lack of physical fitness may result in exertional dyspnea. Multiple other medical conditions also produce dyspnea, including chronic obstructive pulmonary disease (COPD), asthma, pneumonia, and myocardial ischemia (Table 1). In several studies and registries of presumed HF, up to 40% of patients had a history of COPD. Therefore, in the acute care setting, a chief complaint of dyspnea is very nonspecific. Other components of a complete history include assessment of abdominal distention, paroxysmal nocturnal dyspnea, orthopnea, fatigue, weakness, nausea, and vomiting. The presence of paroxysmal nocturnal dyspnea, orthopnea, or dyspnea on exertion increases the likelihood of HF, whereas their absence decreases its likelihood. One of the more reliable indicators that dyspnea is due to an acute exacerbation of HF is a previous history of HF. However, approximately 20% of patients admitted with acute heart failure have a history of COPD. A history is most beneficial when combined with other information but by itself will make the accurate diagnosis of HF challenging. Auscultation for an S3 gallop, assessment for jugular venous distension (JVD), auscultation for pulmonary rales, and assessment for leg edema should be part of the initial evaluation of a patient with suspected HF, and the presence of these signs increases the likelihood of HF. The absence of rales, edema, or JVD lowers the probability of HF. An S3 is difficult to detect in the emergency department. Electronic identification of an S3 should improve detection and diagnosis of HF, although studies have yet to show an effect on patient outcome.

Comparison of Expert and Novice Sonographers’ Performance in Focused Lung Ultrasonography in Dyspnea (FLUID) to Diagnose Patients With Acute Heart Failure Syndrome

OBJECTIVESnThe goal of this study was to examine the ability of emergency physicians who are not experts in emergency ultrasound (US) to perform lung ultrasonography and to identify B-lines. The hypothesis was that novice sonographers are able to perform lung US and identify B-lines after a brief intervention. In addition, the authors examined the diagnostic accuracy of B-lines in undifferentiated dyspneic patients for the diagnosis of acute heart failure syndrome (AHFS), using an eight-lung-zone technique as well as an abbreviated two-lung-zone technique.nnnMETHODSnThis was a prospective, cross-sectional study of patients who presented to the emergency department (ED) with acute dyspnea from May 2009 to June 2010. Emergency medicine (EM) resident physicians, who received a 30-minute training course in thoracic US examinations, performed lung ultrasonography on patients presenting to the ED with undifferentiated dyspnea. They attempted to identify the presence or absence of sonographic B-lines in eight lung fields based on their bedside US examinations. An emergency US expert blinded to the diagnosis and patient presentation, as well as to the residents interpretations of presence of B-lines, served as the criterion standard. A secondary outcome determined the accuracy of B-lines, using both an eight-lung-zone and a two-lung-zone technique, for predicting pulmonary edema from AHFS in patients presenting with undifferentiated dyspnea. Two expert reviewers who were blinded to the US results determined the clinical diagnosis of AHFS.nnnRESULTSnA cohort of 66 EM resident physicians performed lung US on 380 patients with a range of 1 to 28 examinations, a mean of 5.8 examinations, and a median of three examinations performed per resident. Compared to expert interpretation, lung US to detect B-lines by inexperienced sonographers achieved the following test characteristics: sensitivity 85%, specificity 84%, positive likelihood ratio (+LR) 5.2, negative likelihood ratio (-LR) 0.2, positive predictive value (PPV) 64%, and negative predictive value (NPV) 94%. Regarding the secondary outcome, the final diagnosis was AHFS in 35% of patients (134 of 380). For novice sonographers, one positive lung zone (i.e., anything positive) had a sensitivity of 87%, a specificity of 49%, a +LR of 1.7, a -LR of 0.3, a PPV of 50%, and an NPV of 88% for predicting AHFS. When all eight lung zones were determined positive (i.e., totally positive) by novice sonographers, the sensitivity was 19%, specificity was 97%, +LR was 5.7, -LR was 0.8, PPV was 76%, and NPV was 68% for predicting AHFS. The areas under the curve for novice and expert sonographers were 0.77 (95% CIxa0=xa00.72 to 0.82) and 0.76 (95% CIxa0=xa00.71 to 0.82), respectively.nnnCONCLUSIONSnNovice sonographers can identify sonographic B-lines with similar accuracy compared to an expert sonographer. Lung US has fair predictive value for pulmonary edema from acute heart failure in the hands of both novice and expert sonographers.