These images were obtained from a patient with acute kidney injury requiring renal replacement therapy. In the apical view, you can see a large anechoic area beside the left heart = left pleural effusion. Presence of collapsed lung is a clue that the effusion is around the lung. In poor quality images, this can be confused with pericardial effusion.

When possible, POCUS findings should be confirmed in multiple views. Here is the traditional mid-axillary plane view showing left pleural effusion. Note the jellyfish sign and spine sign.

Another example below. Collapsed lung is not very obvious and waiving at you but is still there with bright air next to the left ventricle.

We have previously discussed how right pleural effusion appears from the subcostal window. In here, you can actually see both right and left effusions. Note the anatomic correlation.

Take home point: Get used to appreciating pleural and pericardial effusions in multiple views. Not all patients have every scanning window available (due to body habitus, surgical dressings/drains etc.) Presence of collapsed lung is a big clue for pleural effusion in any view.

Another interesting thing to note in this context: If this patient becomes hypotensive during dialysis, think of left pleural effusion causing tamponade effect. During ultrafiltration, venous return/ intra-cardiac pressure drops. In a patient with low intravascular volume, extra-cardiac pressure due to pleural effusion might cause a drop in cardiac output in this scenario.

Below image obtained from a patient with CKD and hypervolemia demonstrates both pericardial and pleural effusions seen from the apical window (more lateral probe position).