Fig. 1

Vena cava and lung ultrasound profiles. (Profile A) 66-year-old patient admitted to the intensive care unit for community-acquired pneumonia with acute kidney injury KDIGO 3 requiring hemodialysis. The patient had a positive fluid balance of 6.5 L and did not receive vasoactive support. In the right upper anterior thoracic region, multiple coalescent B lines issued from justapleural consolidations typical of bronchopneumonia are visible. As shown in the corresponding video file (Additional files 1, 2, 3, and 4), lung sliding is nearly abolished caused by inflammation/infection of pleural layers. The vena cava appears well filled and does not show any significant collapsibility with respiratory movements. (Profile B) 28-year-old patient admitted to the intensive care unit for a urinary tract infection, and acute kidney injury KDIGO 3 requiring dialysis was diagnosed. The patient had a positive fluid balance of 2.5 L, and he was on vasoactive support. In the right upper anterior thoracic region, predominant A lines are visible. As shown in the corresponding video file (Additional files 1, 2, 3, and 4), lung sliding is normal. The vena cava appears filled and shows not significant collapsibility with respiratory movements. (Profile C) 53-year-old patient admitted to the intensive care unit for an alcoholic acute pancreatitis. AKI (KDIGO) 2 was diagnosed, and intermittent dialysis was initiated. The patient had a positive fluid balance of 8.5 L, and he was on vasoactive support. In the right upper anterior thoracic region, white lines from the pleural line to the bottom (B–lines–comets) are visible. As shown in the corresponding video file (Additional files 1, 2, 3 and 4), lung sliding is normal. The vena cava appears collapsed with respiratory movements. (Profile D) 73-year-old patient admitted to the intensive care unit for an acute mesenteric ischemia treated by an extended right hemicolectomy. The patient developed AKI KDIGO 3, and intermittent dialysis was started. The patient had a positive fluid balance of 5.5 L and did not receive vasoactive support. In the right upper anterior thoracic region, horizontal lines (A lines) are visible. As shown in the corresponding video file (Additional files 1, 2, 3, and 4), lung sliding is normal. The vena cava appears collapsed with respiratory movements