Danielle Parker, DO | EM PGY3

The Article: Randomized, Controlled Trial of Immediate Versus Delayed Goal-Directed Ultrasound To Identify The Cause of Nontraumatic Hypotension In Emergency Department Patients. Jones et al. (2004), Crit Care Med Vol 32, No. 8

The Idea: To determine if the use of physician-performed immediate vs. delayed goal-directed ultrasound protocol in the management of non-traumatic, symptomatic, hypotensive ER patients led to increased diagnosis accuracy

The Study: This was a randomized, control trial performed between July 2002 and September 2003 in the emergency department of Carolinas Medical Center which is an urban tertiary care center with over 100,000 patient visits per year. 184 patients were randomized into two groups: group 1 received immediate (time 0) goal-directed ultrasound in addition to standard care (history, physical, lab work, x ray); group 2 received a delayed goal-directed ultrasound 15 mins after receiving standard care.

Inclusion criteria included: nontrauma emergency department patients age of 17 or older; initial vitals consistent with shock (systolic blood pressure < 100 mmHg systolic or shock index >1) and agreement of two independent observers for at least one sign and one symptom of shock (inadequate tissue perfusion). Once a patient was deemed to be eligible for the study, attending ER physicians and third year ER residents received a random numbered, sealed envelope that contained the randomization assignment (group 1 (immediate US) or 2 (delayed US)) and data collection sheets. Both groups of patients received standard history and physical, lab work, blood gases and xrays. Group 1 received an immediate ultrasound (at time 0) which included the following views: subcostal to assess for RV diastolic collapse, IVC to assess intravascular volume status, parasternal long axis to assess LV function and pericardial effusion, apical 4 chamber to compare ventricle size, hepatorenal recess to assess for free intraperitoneal fluid, pelvis to assess for intraperitoneal fluid and aorta to assess for AAA. Goal-directed US was performed by either a board certified ER attending or a third year ER resident. At time 15 mins examining physicians in both groups completed a data sheet with their differential diagnoses based on the information they had acquired. Group 2 participants then received the same goal-directed US after 15 minutes (time = 15). At 30 mins both groups completed the data sheets again.

The Findings:

Outcomes included the number of viable diagnoses at 15 mins and the rank of their likelihood of occurrence at both 15 and 30 mins. At 15 minutes, group 1 had a median of 4 differential diagnoses while group 2 had a median of 9 (median difference= 5; 95% CI, 4 - 6; Mann-Whitney U test, p < .0001). At 30 minutes group 1 still had a median of 4 diagnoses while group 2 had a revised median of 3 diagnoses (Mann-Whitney U test, p < .4463). At time 15 mins physicians in group one indicated the correct diagnosis in 80% (95% CI, 70 – 87%) of their patients while group 2 was only 50% (95% CI, 40-60%). There was no difference in mortality between patients in group 1 and 2.

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The Takeaway:

It was determined that the incorporation of goal-directed ultrasound in the evaluation of nontraumatic, symptomatic, undifferentiated hypotension helped physicians determine fewer viable diagnoses and causes. Goal-directed ultrasound results in a more accurate impression of patients and final diagnosis.

Robert Cameron Sooby, DO| EM PGY3

The Article:

Accuracy of early rapid ultrasound in shock (RUSH) examination performed by emergency physician for diagnosis of shock etiology in critically ill patients. Ghane et al. (2015). Journal of Emergencies, Trauma, and Shock. 8(1): 5–10.

The Idea:

To determine the accuracy of early RUSH examination in predicting shock type in critically ill patients, and thus allowing for earlier identification of shock etiology and initiation of shock-specific treatments.

The Study:

This was a prospective study performed between April 2013 and October 2013. A total of 52 patients in shock state (defined as SBP < 100 or shock index (HR/SBP) > 1) were enrolled. Excluded were patients with a clear cause for shock (external hemorrhage, active GI bleeding, etc.). Early bedside RUSH was performed on all patients by a single board-certified ED physician, and all patients received standard of care without delay. All patients were followed to document their final diagnosis. Of note, subsequent physicians were not blinded to results of RUSH examination. A one-page checklist was designed incorporating the main components of the RUSH exam, which included evaluation of heart, IVC, thoracic and abdominal compartments, and large vessels. Five subtypes were defined for shock: hypovolemic, distributive, cardiogenic, obstructive and mixed shock. Agreement (Kappa index) of initial impression provided by RUSH with final diagnosis, and also sensitivity, specificity, PPV, and NPV of RUSH for diagnosis of each shock type were calculated.

The Findings:

The mean duration for exam (patient's arrival till RUSH conclusion) was 20 minutes (range, 10-25 minutes). The most frequent types of shock were cardiogenic shock (12 patients, 23.1%) and mixed shock (10 patients, 19.2%). Eight patients had hypovolemic, eight distributive, and seven obstructive type of shock. Seven cases (13.5%) died before the precise cause of shock could be determined and was classified as “not defined etiology”. Kappa index for general agreement between shock type using RUSH protocol and final diagnosis was 0.70 (P value = 0.000), reflecting acceptable general agreement. For hypovolemic shock, RUSH showed excellent sensitivity and good specificity (100% and 94.6%, respectively). NPV and PPV were 94.6% and 80%, respectively. In hypovolemic patients, RUSH protocol showed 86% agreement with final diagnosis (P value < 0.001). For cardiogenic shock, RUSH showed good sensitivity (91.7%) and specificity (97.0%). RUSH showed 89% agreement (P value < 0.001) with final diagnosis. PPV and NPV were 91.7 and 97.0%, respectively. For obstructive shock, RUSH showed excellent sensitivity (100%) and good specificity (97.0%). It had the largest agreement with final diagnosis (92%, P value < 0.001). PPV and NPV were 87.5% and 100%, respectively. For distributive shock, RUSH had excellent specificity (100%) but low sensitivity (75%). It had an acceptable agreement with final diagnosis (83%, P value < 0.001). PPV and NPV were 100% and 94.9%, respectively. For mixed etiology shock, RUSH had excellent specificity (100%) but had the lowest sensitivity (70%). It also had the lowest agreement (74%, P value < 0.001) with final diagnosis. PPV and NPV were 100% and 92.1%, respectively.

The Takeaway:

When performed by experienced clinicians, RUSH can rapidly and accurately diagnose shock type in the undifferentiated hypotensive patient. This in turn allows the clinician to initiate goal-directed therapies earlier and with greater confidence. Due to its inherently dynamic physiologic nature, RUSH was less sensitive in diagnosing distributive shock. Further studies utilizing more physicians and a larger sample size will need to be conducted to assess the shortcomings of this particular study.