The Reverse Cannula: A Novel Technique of Withdrawing Blood

The Editor, Intravenous cannulation is a technique which anesthesiologists do often in their daily practice. It is a technique in which a cannula is placed inside a vein to provide venous access. It allows sampling of blood, fluids, medications, parenteral nutrition, chemotherapy as well as blood products. Intravenous cannula can be used to take blood samples even if it is inside the vein as cannula is just a plastic device inside the vein and there is no risk of "blowing" the vein by the needle once the cannula is inside especially in case of a difficult cannulation or a very small vein.