Ultrasound in Distinguishing between Cardiogenic Pulmonary Edema and ARDS Ananya Anne

Case  64 y/o man with pmh of CHF, COPD, IDDM2, is sent from his nursing home with altered mental status. On presentation he is AAOX1 and follows some commands. His vitals are stable except for O2 sat which is 88%. On physical exam, there are some fine crackles to auscultation in the posterior lung fields. He has 1+ pitting edema in the lower extremities. JVP is not appreciable. His echocardiogram from one month prior shows an EF ~45%. His EKG is unchanged with no acute changes.

CXR Intensive Care Med Nov;39(11):

ARDS? Pulmonary Edema? Both?

Cardiogenic pulmonary edema

Challenges with xray and CT  ARDS not associated with cardiomegaly and cephalization of pulmonary vasculature. Also, not usually associated with pleural effusions.  These differences are difficult to discern in a supine patient and if there is a white out  It takes hours for these differences to show up on chest x ray.  In initial stages, CT shows bilateral areas of diffuse opacification, with aerial bronchograms which can be found in both ARDS and CPE.  CT not an option in unstable patient, is more costly, and exposes patients to radiation.

What’s the utility of sonography is differentiating ARDS from CPE?  Copetti et al, Cardiovascular Ultrasound,  Methods  18 patients admitted to ICU with ARDS based on American-European Consensus Conference: - 1) acute onset, bilateral infiltrates on chest radiography 2) pulmonary- artery wedge pressure less than 18 mmHg or the absence of clinical evidence of left atrial hypertension 3) PaO 2 /FiO 2 ratio <= 200 in ARDS  40 patients with CPE based on: - clinical signs and symptoms, electrocardiogram, chest x-ray, and Color- Doppler echocardiography.

-Convex probe: mHz -Linear probe: 5-7 mHz - 5 areas

 Ultrasound performed on first day of admission after diagnosis. Evaluated based on following signs:  AIS defined as more than 3 ULCs for each area  Pleural line abnormalities  Areas with reduced lung sliding  Spared areas  Consolidations  Pleural effusion  Lung pulse

Ultrasound Lung Comets (ULC)

Pleural Line Abnormalities

Spared Areas

Consolidations

Pleural Effusion

Lung Pulse

Results Distribution of ultrasound signs in the two groups ALI/ARDS (18 pt.)APE (40 pt.)p Sex (n° males)11 (61%)25 (62.5%)0.92 (ns) Mechanical ventilation (n) 16 (88.8%)8 (20%)< AIS18 (100%)40 (100%)ns Pleural line abnormalities 18 (100%)10 (25%)< Reduction or absence of lung sliding 18 (100%)0< "Spared areas"18 (100%)0< Consolidations15 (83.3%)0< Pleural effusion12 (66.6%)38 (95%)0.004 "Lung pulse"9 (50%)0<

Sensitivity and Specificity of Sonographic Signs in Each Group SONOGRAPHIC SIGNS SENSITIVITYSPECIFICITY ALI/ARDSAPEALI/ARDSAPE AIS100% 0% Pleural line abnormalities 100%25%45%0% Reduction or absence of lung sliding 100%0%100%0% "Spared areas"100%0%100%0% Consolidations83.3%0%100%0% Pleural effusion66.6%95%5%33.3% "Lung pulse"50%0%100%50%

Other Observations  Posterior lung fields had more homogenous evidence of AIS.  Areas of consolidation and air bronchograms were often found in posterior lung fields at the bases.  Relative compactness of ULCs seemed to correlate with reduced lung sliding in those areas and level of lung injury.  Compactness of ULCs also seemed to correlate with the lung pulse sign  Involvment of pleural line followed degree and distribution of ALI.  Pleural effusion more often present and larger in CPE vs ARDS, but cannot be relied upon for differential diagnosis.  Changes in consolidation areas were observed using sono after start of mechanical ventilation in ARDS.

Limitations  Diagnosis known before lung findings  Chest x ray as part of the criteria  Sample size  Mixed picture  Time from presentation to ultrasonography  Counfounding comorbidities  Skill of ultrasonographer?

Conclusion “In critically ill patients ultrasound demonstration of a dyshomogeneous AIS with spared areas, pleural line modifications and lung consolidations is strongly predictive, in an early phase, of a non cardiogenic pulmonary edema” There is utility of ultrasound in distinguishing between ARDS and CPE in the critically ill patient. The repeatability of ultrasound may be useful in assessing patient responsiveness to mechanical ventilation in ARDS.

References  American Journal Of Emergency Medicine (2012). "Three-view Bedside Ultrasound for the Differentiation of Acute Respiratory Distress Syndrome from Cardiogenic Pulmonary Edema." American Journal of Emergency Medicine 30 (2012): n. pag. Web.  Copetti, Roberto, Gino Soldati, and Paolo Copetti. "Chest Sonography: A Useful Tool to Differentiate Acute Cardiogenic Pulmonary Edema from Acute Respiratory Distress Syndrome." Cardiovascular Ultrasound 6.16 (2008): n. pag. Web.  Ishii, Hiroshi. "Comparison Of Ct Features Of Ali/Ards And Cardiogenic Pulmonary Edema." Chest (2011): n. pag. Web.  Durant, Andrea. "Ultrasound Detection of Lung Hepatization." Western Journal of Emergency Medicine 11.4 (2010): n. pag. Web.