¿Cómo rehidratar terneros a través de la “vena de la oreja”?

Current recommendations for ear vein catheterization in neonatal calves are to use a 22 gauge, 1-in (0.9 × 25 mm) over-the-needle catheter (ie, Vasocan Braunüle, B. Braun Melsungen AG, Melsungen, Germany) with a butterfly-shaped wing. Other suitable catheters for ear vein catheterization should incorporate a guide wire needle to facilitate easier placement. Older calves and adult cattle require larger gauge sizes for increased flow rates. A disadvantage of the over-the-needle catheters is that they may fray or splinter at the tip during insertion and then must be discarded. Advancing an already frayed catheter should be avoided because it damages the internal wall of the vein and increases the risk of thrombosis.97

The anatomy of the ear veins may differ slightly among calves. Normally there are one or two cranial, one medial, and one caudal ear vein that are large enough for catheterization. Identification of the ear vessels is important to avoid arterial puncture or placement of the catheter into the auricular artery. This artery is located between the cranial ear vein and the medial ear vein. It is usually more prominent than the ear veins and is visible even before applying a tourniquet. Identification of the auricular artery by palpating for a pulse is difficult; however, the artery feels harder than the veins and can be rolled under the skin. The author prefers the cranial ear vein for catheterization (Fig. 3A) followed by the medial vein. The cranial vein runs dorsally across the auricular pinna, which is flatter and more rigid than the caudal part of the ear. Catheterization should begin as far distally as possible to allow for repeated attempts more proximally if the first attempt is not successful. If the tip of the catheter lies too close to the base of the ear, the fluid flow rate may be slow.