Kenton L. Anderson

Diagnosing heart failure among acutely dyspneic patients with cardiac, inferior vena cava, and lung ultrasonography☆ , ☆☆ ,★

BACKGROUND Rapid diagnosis (dx) of acutely decompensated heart failure (ADHF) may be challenging in the emergency department (ED). Point-of-care ultrasonography (US) allows rapid determination of cardiac function, intravascular volume status, and presence of pulmonary edema. We test the diagnostic test characteristics of these 3 parameters in making the dx of ADHF among acutely dyspneic patients in the ED. METHODS This was a prospective observational cohort study at an urban academic ED. Inclusion criteria were as follows: dyspneic patients, at least 18 years old and able to consent, whose differential dx included ADHF. Ultrasonography performed by emergency sonologists evaluated the heart for left ventricular ejection fraction (LVEF), the inferior vena cava for collapsibility index (IVC-CI), and the pleura sampled in each of 8 thoracic regions for presence of B-lines. Cutoff values for ADHF were LVEF less than 45%, IVC-CI less than 20%, and at least 10 B-lines. The US findings were compared with the final dx determined by 2 emergency physicians blinded to the US results. RESULTS One hundred one participants were enrolled: 52% male, median age 62 (25%-75% interquartile, 53-91). Forty-four (44%) had a final dx of ADHF. Sensitivity and specificity (including 95% confidence interval) for the presence of ADHF were as follows: 74 (65-90) and 74 (62-85) using LVEF less than 45%, 52 (38-67) and 86 (77-95) using IVC-CI less than 20%, and 70 (52-80) and 75 (64-87) using B-lines at least 10. Using all 3 modalities together, the sensitivity and specificity were 36 (22-51) and 100 (95-100). As a comparison, the sensitivity and specificity of brain natriuretic peptide greater than 500 were 75 (55-89) and 83 (67-92). CONCLUSION In this study, US was 100% specific for the dx of ADHF.

Antinociception induced by chronic exposure of rats to cigarette smoke

To investigate if chronic exposure to cigarette smoke induces analgesia, rats were exposed to concentrated cigarette smoke in an environmental chamber over four successive 5-day blocks (6 h/day), with 2 smoke-free days between blocks. A control group was exposed to room air. Tail flick latencies increased significantly (analgesia) during each smoke exposure block, with a relative decline in analgesia across blocks (tolerance) and a return to control levels during the first three smoke-free interludes while remaining higher after the conclusion of the 4-week exposure period. Mechanical (von Frey) withdrawal thresholds declined over time in smoke-exposed and control groups, with the smoke-exposed group showing significantly lower thresholds. Plasma nicotine reached 95.4 +/- 32 (S.D.) ng/ml at the end of weekly smoke exposure and declined to 44.9 +/- 10.6 ng/ml 24 h after withdrawal. Rats lost weight during smoke exposure and quickly regained weight during smoke-free interludes and at the cessation of smoke exposure. Analgesia may contribute to the initiation of smoking, and rapid reversal of the analgesic effect following acute exposure may contribute to the difficulty in quitting smoking.

Foreign Bodies in the Gastrointestinal Tract and Anorectal Emergencies

Of all ingested foreign bodies (FBs) brought to the attention of physicians (probably a small minority of the total), 80% to 90% pass spontaneously; however, 10% to 20% require endoscopic removal, and about 1% require surgery. The article divides the GI tract into regions in which the anatomy, presentation, clinical findings, and management of FBs are distinct. The final third of this article describes the management of anorectal emergencies. An understanding of anatomy and common pathological conditions allows the emergency physician to make a diagnosis and provide relief and/or resolution in most cases.

The effect of vessel depth, diameter, and location on ultrasound-guided peripheral intravenous catheter longevity

INTRODUCTION Ultrasound-guided peripheral intravenous catheters (USGPIVs) have been observed to have poor durability. The current study sets out to determine whether vessel characteristics (depth, diameter, and location) predict USGPIV longevity. METHODS A secondary analysis was performed on a prospectively gathered database of patients who underwent USGPIV placement in an urban, tertiary care emergency department. All patients in the database had a 20-gauge, 48-mm-long catheter placed under ultrasound guidance. The time and reason for USGPIV removal were extracted by retrospective chart review. A Kaplan-Meier survival analysis was performed. RESULTS After 48 hours from USGPIV placement, 32% (48/151) had failed prematurely, 24% (36/151) had been removed for routine reasons, and 44% (67/151) remained in working condition yielding a survival probability of 0.63 (95% confidence interval [CI], 0.53-0.70). Survival probability was perfect (1.00) when placed in shallow vessels (<0.4 cm), moderate (0.62; 95% CI, 0.51-0.71) for intermediate vessels (0.40-1.19 cm), and poor (0.29; 95% CI, 0.11-0.51) for deep vessels (≥1.2 cm); P < .0001. Intravenous survival probability was higher when placed in the antecubital fossa or forearm locations (0.83; 95% CI, 0.69-0.91) and lower in the brachial region (0.50; 95% CI, 0.38-0.61); P = .0002. The impact of vessel depth and location was significant after 3 hours and 18 hours, respectively. Vessel diameter did not affect USGPIV longevity. CONCLUSION Cannulation of deep and proximal vessels is associated with poor USGPIV survival. Careful selection of target vessels may help improve success of USGPIV placement and durability.

Inter-Rater Reliability of Quantifying Pleural B-Lines Using Multiple Counting Methods

Sonographic B‐lines are a sign of increased extravascular lung water. Several techniques for quantifying B‐lines within individual rib spaces have been described, as well as different methods for “scoring” the cumulative B‐line counts over the entire thorax. The interobserver reliability of these methods is unknown. This study examined 3 methods of quantifying B‐lines for inter‐rater reliability.

Cardiac Evaluation for Structural Abnormalities May Not Be Required in Patients Presenting With Syncope and a Normal ECG Result in an Observation Unit Setting

STUDY OBJECTIVE Patients with syncope are frequently managed in observation units and receive serial examinations, monitoring for arrhythmias, and structural analysis of the heart. The primary aim of this study is to determine the utility of structural analysis of the heart in syncope patients who are being managed in an observation unit and have a normal ECG result. METHODS This is a retrospective, observational chart review of all consecutive adult patients observed during 18 months at an urban, academic medical center. A case report form with demographics, ECG interpretations, and structural analysis of the heart data was generated and all variables were defined before data extraction. Subjects with an ECG demonstrating any arrhythmia, premature atrial contraction, premature ventricular contraction, pacing, second- and third-degree blocks, and left bundle branch block were excluded from the normal ECG group. An abnormal cardiac structure was defined as an ejection fraction less than 45%, severe hypertrophy, or severe valvular abnormality. Ten percent of cases were evaluated by a second extractor to verify accuracy. Descriptive statistics with confidence intervals (CIs) and interquartile ranges (IQRs; 25%, 75%) are used. RESULTS Three hundred twenty-three subjects were managed in the observation unit for syncope, 48% were men, and their median age was 66 years (25%, 75% IQR 52, 80). Two of 323 (0.6%; 95% CI 0.2% to 2.2%) had an arrhythmia; 1 of 323 had a non-ST-segment myocardial infarction (0.3%; 95% CI 0.1% to 1.7%). Of the 323 patients, 267 had a normal ECG result and 235 (88%) had their cardiac structure evaluated. Forty-eight percent of the normal ECG group were men, and the median age was 65 years (25%, 75% IQR 52, 79). Zero of 235 patients (0%; 95% CI 0% to 1.6%) had a structural abnormality identified on evaluation, and 2 of 18 (11%; 95% CI 3.1% to 32.8%) had an abnormal stress echocardiogram result. CONCLUSION Structural abnormalities are unlikely in syncope patients with a normal ECG result. Care should focus on excluding arrhythmias and acute coronary syndrome.

Left Ventricular Compressions Improve Hemodynamics in a Swine Model of Out-of-Hospital Cardiac Arrest

ABSTRACT Introduction: We hypothesized that chest compressions located directly over the left ventricle (LV) would improve hemodynamics, including coronary perfusion pressure (CPP), and return of spontaneous circulation (ROSC) in a swine model of cardiac arrest. Methods: Transthoracic echocardiography (echo) was used to mark the location of the aortic root and the center of the left ventricle on animals (n = 26) which were randomized to receive chest compressions in one of the two locations. After a period of ten minutes of ventricular fibrillation, basic life support (BLS) with mechanical cardiopulmonary resuscitation (CPR) was initiated and performed for ten minutes followed by advanced cardiac life support (ACLS) for an additional ten minutes. During BLS the area of maximal compression was verified using transesophageal echo. CPP and other hemodynamic variables were averaged every two minutes. Results: Mean CPP was not significantly higher in the LV group during all time intervals of resuscitation; mean CPP was significantly higher in the LV group during the 12–14 minute interval of BLS and during minutes 22–30 of ACLS (p < 0.05). Aortic systolic and diastolic pressures, right atrial systolic pressures, and end-tidal CO2 (ETCO2) were higher in the LV group during all time intervals of resuscitation (p < 0.05). Nine of the left ventricle group (69%) achieved ROSC and survived to 60 minutes compared to zero of the aortic root group (p < 0.001). Conclusions: In our swine model of cardiac arrest, chest compressions over the left ventricle improved hemodynamics and resulted in a greater proportion of animals with ROSC and survival to 60 minutes.

The utility of transvaginal ultrasound in the ED evaluation of complications of first trimester pregnancy

BACKGROUND For patients with early intrauterine pregnancy (IUP), the sonographic signs of the gestation may be below the resolution of transabdominal ultrasound (TAU); however, it may be identified by transvaginal ultrasound (TVU). We sought to determine how often TVU performed in the emergency department (ED) reveals a viable IUP after a nondiagnostic ED TAU and the impact of ED TVU on patient length of stay (LOS). METHODS This was a retrospective cohort study of women presenting to our ED with complications of early pregnancy from January 1, 2007 to February 28, 2009 in a single urban adult ED. Abstractors recorded clinical and imaging data in a database. Patient imaging modality and results were recorded and compared with respect to ultrasound (US) findings and LOS. RESULTS Of 2429 subjects identified, 795 required TVU as part of their care. Emergency department TVU was performed in 528 patients, and 267 went to radiology (RAD). Emergency department TVU identified a viable IUP in 261 patients (49.6%). Patients having initial ED US had shorter LOS than patients with initial RAD US (median 4.0 vs 6.0 hours; P < .001). Emergency department LOS was shorter for women who had ED TVU performed compared with those sent for RAD TVU regardless of the findings of the US (median 4.9 vs 6.7 hours; P < .001). There was no increased LOS for patients who needed further RAD US after an indeterminate ED TVU (7.0 vs 7.1 hours; P = .43). There was no difference in LOS for those who had a viable IUP confirmed on ED TAU vs ED (median 3.1 vs 3.2 hours, respectively; P < .32). CONCLUSION When an ED TVU was performed, a viable IUP was detected 49.6% of the time. Emergency department LOS was significantly shorter for women who received ED TVU after indeterminate ED TAU compared with those sent to RAD for TVU, with more marked time savings among those with live IUP diagnosed on ED TVU. For patients who do not receive a definitive diagnosis of IUP on ED TVU, this approach does not result in increased LOS.

Point-of-care ultrasound diagnoses acute decompensated heart failure in the ED regardless of examination findings

44 (73%). Seemingly, the 2 most important clues of the diagnosis of ADHF in any clinical contextwerenot observed in all patients, andwedo should know also if and how these symptoms were associated. We wonder if such limitation could be related to the ill-defined quality of the assessment description of rales (basal or diffuse), which makes questionable even the diagnosis of ADHF or are a consequence of other factors, for instance the need of rush when facing critical patients. But how canwe trust in the diagnostic efficacy ofmore complex procedures if the rush is seemingly preventing even an adequate assessment of physical signs? The currentwork-up of patientswith ADHF includes the assessmentof pulmonary rales, usually alongwith themonitoringblood pressure, heart rate, pulse oximetry, and other measurements. In our opinion, someof themshouldbe included in the statistics of predictivity, and the failure of physicians to detect them deserves some comment. Ejection fraction (EF) assessedby echocardiography is included indata analysis, but echocardiographic assessment was quite limited: “Left ventricular EF was visually estimated as the reduction in the crosssectional area of the left ventricle viewed in the short axis.” Can authors comment on this point? Echocardiography [4] is probably faster to perform in comparison of the 8 areas assessment such as LUS scan does and the subsequent calculation of the score requires, at least in our experiencewithpostgraduate trainees. Authors [1] should report the time that was necessary to perform LUS in the patients observed in this study. Authors claim very serious limitations in the US assessment of inferior vena cava (IVC) respiratory changes: “The choice of sonographic window was determined by availability (limited by dressings, wounds, bowel gas, or habitus) and sonologist preference.” Despite these limitations, which apparently affected the actual feasibility of the procedure in some patients, US IVC is described as a very reliable measure to be used in the ADHF diagnosis work-up [1]. In addition, this point is not sufficiently discussed, and limitations of IVC collapsibility index criterion should be better considered. Briefly: 1) Canwe trust in adiagnosis ofADHFwithout any signof lung rales? 2) Physical examination clues, such as rales, were used in the single variables and in the combinations of multiple variables (LUS, EF, and IVC) predictivity analysis. 3) Interobserver/intraobserver variation analysis for b-line assessment should be reported. 4) Because it is known that b lines can be seen in other conditions, such as pulmonary fibrosis, COPD, and lymphangitis [5-9], we should know in how many patients with dyspnea but without ADHF, b-line (N10) increase was found: were they 0 of 57 in no-ADHF patients? 5) The lack of report of the likely presence of pleural effusion,which can be an additive clues useful in the diagnosis of ADHF [10] and the use of artifact insteadof LUS imaging [11,12] need comments.

Point-of-Care Ultrasound in Austere Environments: A Complete Review of Its Utilization, Pitfalls, and Technique for Common Applications in Austere Settings

With the advent of portable ultrasound machines, point-of-care ultrasound (POCUS) has proven to be adaptable to a myriad of environments, including remote and austere settings, where other imaging modalities cannot be carried. Austere environments continue to pose special challenges to ultrasound equipment, but advances in equipment design and environment-specific care allow for its successful use. This article describes the technique and illustrates pathology of common POCUS applications in austere environments. A brief description of common POCUS-guided procedures used in austere environments is also provided.