Measuring arterial blood pressure, and collecting arterial blood gas for analyzing arterial blood gases, are important considerations when monitoring animals undergoing surgery. This video describes in detail the catheterization of the brachial artery, a relatively fast and simple procedure, that is particularly useful for procedures that involve the caudal ventral and caudal dorsal back and hind limbs of pigs. This video is a compilation of the brachial artery catheterization of three pigs, and is also part of a non-recovery surgical procedure.
The anesthetic protocol includes, one, the intramuscular administration of a premedication cocktail that contains, ketamine hydrochloride, xylazine hydrochloride, and glycopyrrolate hydrochloride. Two, inhalational anesthesia with isoflurane gas, and three, intravenous analgesia, with continuous remifentanil hydrochloride infusion. The the distal brachial artery is found by digital palpation.
The surgical site is marked. The artery lies between the olecranon, and the flexor aspect of the elbow joint. The artery travels in a proximal direction towards the scapula, and traverses the humerus.
A 10%povidone iodine surgical scrub solution is applied to the site of brachial artery catheterization. To access the artery, the skin is incised with a scalpel. The skin incision is approximately six centimeters in length.
Use gentle tissue dissection with blunt instruments, and swabs, to identify the artery. A retractor is used to separate the tissues, allowing better access to the underlying structures. Continue gentle dissection.
Tissues are moistened with warm saline. The brachial artery, brachial vein, and median nerve, are identified by uppercase letters, A, V, and N, respectively. Create a tunnel underneath the artery with blunt instruments.
Three two zero polyglactin sutures are passed underneath the brachial artery. The artery displays strong arterial blood pressure pulsations. The sutures are intentionally placed loosely around the artery.
A distal suture is used to occlude the vessel, and later secures the catheter into the vessel. The proximal sutures are used to secure the catheter within the vessel. Insert the catheter into the artery, and advance the catheter into the vessel to the catheter hub.
The middle suture secures the catheter within the artery. Remove the stylet, and quickly cap the catheter to minimize bleeding. Flush the area with warm saline.
Secure the distal suture around the catheter hub. Attach the intravenous extension line to the catheter. Flush with warm saline, and clean the area.
Flush the catheter with saline to ensure catheter patency, and good arterial blood flow. Two additional sutures are secured around the catheter hub, to enhance catheter stability. The muscle layer is closed with two zero polyglactin suture, using a simple continuous suture pattern.
The skin is closed with two zero polypropylene suture, using a simple interrupted suture pattern. For optimal arterial blood pressure measurements, a catheterized foramen is extended at a 40-degree angle from the midline of the pig's vertebral column. The monitor shows hemodynamic and respiratory parameters, and body temperature.
The arterial blood pressure values, and arterial pressure waves, are shown in purple. Figure one represents the time required to catheterize the brachial artery in seven pigs. The average time to catheterize the pigs was 35.2 minutes.
The solid line represents the mean, and the shaded area represents the standard error of the mean. Figure two represents averaged arterial blood pressure measurements during 120 minutes of surgery. Blood pressure measurements include arterial systolic pressure, arterial diastolic pressure, and mean arterial pressure.
Table one represents average brachial artery blood measurements. Time zero minutes shows the arterial blood measurements collected prior to surgery. Time 120 minutes shows the brachial artery measurements following 120 minutes of surgery.
In conclusion, the catheterization of brachial arteries in pigs, is an excellent alternative method to measure arterial blood pressure, and collect arterial blood, for blood gas sampling. Although brachial artery catheterization requires modest amounts of tissue dissection, it is a relatively rapid procedure that can reliably produce accurate arterial blood measurements.
