Pericardial Effusions: Time to Intervention

Pericardial effusion byte

Emergency department point-of-care ultrasonography improves time to pericardiocentesis for clinically significant effusions

Clinical and Experimental Emergency Medicine September 2017 - Pubmed Link


Take Home Points

1. This study was limited but did not provide definitive evidence that point of care ultrasound improves time to intervention or mortality in patients with significant pericardial effusion.

2. Because classic signs and symptoms are often not present, maintain a low threshold to perform cardiac ultrasound to evaluate for pericardial effusion and tamponade.


Background

Point of care ultrasound thrives on identifying an actionable diagnosis in sick patients. That’s why cardiac tamponade is a great example of how POCUS can be useful. Your physical exam and history are not as accurate as you would like so being able to use ultrasound can help get the patient to the life-saving procedure they need. That’s the basis of this study. The authors wanted to see if using point of care ultrasound to identify significant pericardial effusions early would change patient centered outcomes such as time to intervention, length of stay, or mortality.


Questions

In patients with cardiac tamponade or a large pericardial effusion, does using POCUS in the emergency department affect time to procedure and outcomes?


Population

Single center in Israel

Data collected October 2007 to February 2012


Inclusion:

  • Presented to the emergency department and had hospital discharge diagnosis of cardiac tamponade or pericardial effusion

  • Clinically significant effusion. Defined as effusion that would lead to referral for pericardiocentesis or operative repair

Exclusion:

  • Trauma


Design

Retrospective cohort study, single center academic ED

Patient were identified from a hospital database (searching using an ICD code) who had a large pericardial effusion or tamponade. These were then split into two groups - POCUS (those who received a point of care ultrasound in the emergency department) and non-POCUS (those who had not).

They recorded information from chart including demographics, medical background, ECG, chest xray, ultrasound, official echocardiogram, patient outcomes, type of procedures, analysis of pericardial fluid, length of hospital stay, status at hospital discharge.

Door to pericariocentesis time recorded from a cardiology database system.

Outcomes:

  • Multiple Primary Outcomes (sad face): Door-to-pericardiocentesis time, Amount of pericardiocentesis fluid, and Length of hospital stay

  • Secondary Outcome: Mortality


Intervention

The intervention was receiving a point of care ultrasound in the emergency department.


Who did the ultrasounds?

6 physicians - 5 attendings and 1 fellow

  • Trained in emergency ultrasound according to curriculum of the Israeli Association of Emergency Medicine


The Scan

Phased array probe

Phased

Standard 4 view focused cardiac ultrasound


5 Minute Sono - Pericardial Effusion

5 Minute Sono - Tamponade

5 Minute Sono - Pericardiocentesis


Results

Patients

Over 4.5 years, there were 500,000 ED visits and 1000 POCUS studies.

73 total patients with significant pericardial effusions

  • 18 of these patients were diagnosed with POCUS

  • 55 were diagnosed by other means


Patient characteristics:

  • POCUS group had lower systolic BP (117.6 vs 134.8)

  • POCUS group had more syncope (3 vs 0)

  • POCUS had less infiltrates or effusions on CXR (17.6% vs 71.6%)

  • The majority of CXRs in both groups showed cardiomegaly (70.6% POCUS, 86.4% non-POCUS).

  • Malignancy was the most common cause of effusion in both groups

  • 82.6% underwent a pericardiocentesis or surgery


Primary Outcomes

Door to Pericardiocentesis → No statistically significant difference

POCUS: 11.3 hours (± 13.8)

Non-POCUS: 70.2 hours (± 126.2)

P = 0.055


Amount of Fluid Drained → No statistically significant difference

POCUS: 660.6 mLs (± 339.9)

Non-POCUS: 825.8 mLs (± 409.2)

P = 0.139


Length of Hospital Stay → No statistically significant difference

POCUS: 5.0 days (±0.6)

Non-POCUS: 7.0 days (±0.9)

P = 0.222


Secondary Outcomes

Death → No statistically significant difference

POCUS: 1 death (5.6%)

Non-POCUS: 4 deaths (7.3%)

P = 0.802


Limitations

Study performed in Israel which may have different patient population and practice environment, limiting external validity.

Retrospective design is not ideal. Many patients could have been missed. Although RCT may be best evidence, it would be unethical to randomize a patient with possible tamponade to not get an immediate ultrasound. One possibility would be prospective study of patients with possible tamponade who all get POCUS compared to matched controls.

Population may have been too small to draw conclusions from. Small number of POCUS studies, only 18 in this study.

No strict criteria for “significant” effusion. Do all effusions need pericardiocentesis? No. The decision to perform a procedure is multi-factorial and can be somewhat complex, this limits the conclusions drawn from these findings.

Not very sick population - very few deaths, very few hypotensive. Ultrasound is likely going to make the most difference in the most critically ill where time matters most.

Selection bias - those who got POCUS studies likely were thought to need them. You look because you think you might find something.


Discussion

The main question is - when to perform a scan for a pericardial effusion? Tamponade is a diagnosis you can't miss. Unfortunately, as this study shows, clinical diagnosis is difficult. Many of these patients were not hypotensive, less than half presented with dyspnea, and many even had an infiltrate on their chest xray! Another cool tamponade study confirmed that not many of these patients will present with Beck's triad or obvious clinical signs pointing towards this diagnosis. That is why many suggest performing a cardiac ultrasound in undifferentiated dyspnea, undifferentiated hypotension, and cardiac arrest. You can certainly find other important causes for the presentation as well. Some people might say that you shouldn't apply a test for a relatively rare disease to population with a common complaint (such as dyspnea). I think the risk of the study (taking time and resources) is low compared to the potential gains of finding a patient who needs a life-saving intervention. What do you think? When should we be doing cardiac ultrasounds for suspected pericardial effusion or tamponade?


Take Home Points

1. This study was limited but did not provide definitive evidence that point of care ultrasound improves time to intervention or mortality in patients with significant pericardial effusion.

2. Because classic signs and symptoms are often not present, maintain a low threshold to perform cardiac ultrasound to evaluate for pericardial effusion and tamponade.


Our score

2 Probes


Published on 12/18/17 04:00 AM
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