Brachial Artery Catheterization in Swine
PREPARAÇÃO DO INSTRUTOR
CONCEITOS
PROTOCOLO DO ALUNO
All procedures on experimental animals described in both the video and manuscript were approved by the Institutional Animal Care and Use Committee of the University of Alberta
1. Surgical anesthesia and surgical preparation of the pigs.
- Premedicate 50 kg Landrace-Yorkshire commercial pigs intramuscularly with the anesthetic drug cocktail containing ketamine hydrochloride (22 mg/kg,), xylazine hydrochloride (2.2 mg/kg) and glycopyrrolate hydrochloride (10 µg/kg).
- Set up all equipment involved with monitoring clinical parameters at the end of the table near the pig's head. Ensure the equipment will not restrict access to the pig. Produce accurate arterial blood pressure measurement by placing the pressure transducer in a horizontal plane, level with the heart.
- Anesthetize the pigs with inhaled isoflurane gas (4%-5% isoflurane at 500-1000 mL/min O2) using a properly sized face mask. Visualize the vocal cords with a veterinary laryngoscope (17-25 cm long straight blade) and apply topical 10% lidocaine spay to the vocal cords to limit the risk of laryngospasm and airway obstruction.
- Intubate the pigs by inserting a cuffed endotracheal tube (9.0 mm internal diameter (ID)) through the vocal cords and maintain anesthesia with isoflurane gas (0.5%-3.0% isoflurane at 1000-2000 mL/min O2). Ventilate the pig on a mechanical ventilator (18-22 breaths/min) and ensure all expired anesthetic gas is scavenged and vented outside the surgical suite. Assess the level of anesthesia by jaw tone, and both pedal and palpebral reflex responses.
NOTE: Administer intravenous Lactated Ringer's Solution (LRS, 10-50 mL/kg/h; see step 1.6) to enhance hemodynamic function and reduce isoflurane gas anesthesia induced depression of cardiovascular output in swine26. - Secure a pulse oximeter to the mucosal surface of the tongue with medical tape to monitor heart rate and the saturation of peripheral blood oxygenation (SpO2). Insert a temperature probe approximately 2-4 cm into the nasal cavity to monitor body temperature. Place the pigs on a heated table to maintain normal body temperature (38-40 °C) during the surgical procedure.
- Ensure surgical sterility with proper tissue preparation.
- Clean the external surface of the ear to prepare for venous catheterization with 10% povidone-iodine surgical scrub solution and allow the solution to air dry.
- With a 20 G, 1 inch intravenous catheter, catheterize a marginal ear vein to deliver either intravenous fluids (LRS; 10-50 mL/kg/h) or the addition of other anesthetic agents.
- Enhance pig anesthesia and analgesia if needed for invasive procedures with continuous intravenous remifentanil hydrochloride infusion (0.05-0.14 µg/kg/min).
- Place the pig in a lateral recumbent position and gently extend the front leg approximately 10-12 cm away from the shoulder. Clip the hair on the skin surface of the medial aspect of the brachium (upper forelimb). Landmark the distal brachial artery pulse by palpation.
NOTE: The landmarked location of the artery lies along an oblique plane with the brachium approximately 9 cm from the olecranon, and 5 cm from the flexor aspect of the elbow joint. The brachial artery travels proximally towards the caudal third of the scapula traversing the humerus. - Similarly to step 1.6, ensure surgical sterility with proper tissue preparation. Clean the skin surface with 10% povidone-iodine surgical scrub solution and allow the solution to air dry. Drape the brachial artery catheterization site with four small disposable surgical drapes.
2. Tissue dissection and catheterization of the brachial artery
- Make a 6 cm skin incision with a scalpel blade to expose the underlying tissue. Bluntly dissect with Metzenbaum scissors along the medial surfaces of the biceps brachii, deepening the dissection, until the pulsating artery is identified.
- Use cotton swabs to gently tease away the adventitia from the brachial artery, median nerve and brachial vein; structures that are in close proximity and within the same fascial plane. Gentle dissection is required, importantly ensuring minimal injury to the median nerve during the procedure. The brachial artery lies approximately 2.0-2.5 cm underneath the skin and is medial to coracobrachialis and lateral to the tensor fasciae antibrachii and overlies a small segment of the medial head of the triceps muscle27,28.
NOTE: Place a retractor to keep the skin incision open, allowing easier access to the brachial artery. Place a second retractor (optional) to further assist in vessel exposure. - Moisten all tissues with warm saline (37 °C) for the entire dissection to retain better structural integrity and improved tissue handling during the procedure.
- Create a tunnel under the artery with blunted forceps, then pass three 2-0 polyglactin sutures underneath the artery. Intentionally, leave the ends of this suture relatively long (3-4 cm) to secure the catheter to the artery. Add a "loose suture tie" allowing for quick catheter fastening, to the first two sutures that are separated 1.0 cm from each other and are approximately 1.5-2.0 cm proximal to the third distal suture. Ligate the most distal suture first to occlude the artery.
- Insert a 22 G, 1 inch peripheral venous catheter into the artery and then advance the catheter (completely to the catheter hub) off the stylet into the vessel. Partially withdraw the stylet from the catheter to visualize arterial blood, ensuring proper vessel placement of the catheter. Then, firmly secure the catheter in the vessel by tying the middle suture. Remove the stylet and quickly cap the catheter to minimize bleeding.
- Flush the incision and catheter with warm saline (37 °C). Tie the most proximal suture and importantly ensure that the distal suture is tightly secured around the catheter hub as this improves catheter stability and reduces accidental slippage of the catheter from the artery (i.e., during pig repositioning).
NOTE: If the initial placement of the catheter into the artery fails, or the vessel is injured, reinsert the catheter into the artery at a position approximately 0.25 cm proximal to the initial catheter insertion site. - Quickly attach the LRS filled intravenous extension line with the connected arterial pressure transducer to the catheter, and then lavage the surgical site with warm saline (37 °C), keeping tissues moist, and clean any blood that spilled into the surrounding tissue. Flush the catheter with saline to ensure catheter patency and prevent blood clots from forming along the catheter wall.
NOTE: Check for transducer arterial blood pressure line failures (i.e., leaks), establish transducer baseline by zeroing arterial pressure monitor measurements, and ensure proper arterial blood pressure wave formations. - Ensure continued catheter patency by maintaining the flush port of the extension line pressurized above 250 mmHg, with a pressure infuser bag delivering 3-5 mL/min LRS.
- Optional: Place either two 2-0 polypropylene or two 2-0 polyglactin sutures around the catheter hub or intravenous extension line hub to further improve catheter stability within the artery.
3. Tissue closure and body positioning
- Close the muscle layers with a simple continuous suture pattern with a 2-0 polyglactin suture on a cutting or tapered needle and close the skin in a simple interrupted suture pattern with a 2-0 polypropylene suture on a cutting needle.
NOTE: Interchangeably, 2-0 polyglactin or 2-0 polypropylene sutures can be used to close muscle and skin. - Place the pig in ventral recumbency by rotating the abdomen of a lateral recumbent pig toward the surgical table. A left sided lateral recumbent pig is rotated in a clockwise direction, while a right sided lateral recumbent pig is rotated in a counter clockwise direction.
- Place the catheterized forelimb at a 40° angle to the midline of the vertebral column of the pig. This forelimb positioning generates the best arterial blood flow and the most accurate arterial blood pressure measurements.
4. Monitoring clinical parameters
- Measure hemodynamic and respiratory parameters as well as temperature throughout the entire anesthetic and surgical procedure using proper monitoring equipment.
Brachial Artery Catheterization in Swine
Learning Objectives
Brachial artery catheterization allows for continuous monitoring of arterial blood pressure and intermittent sampling of arterial blood during extended surgical procedures in swine. Measured parameters were collected from seven 50 kg Landrace-Yorkshire commercial pigs as described. The total time required to catheterize the brachial artery was 35.2 ± 4.4 min from the initial artery landmarking to final surgical incision closure (Figure 1). The arterial pressures were measured over 120 min and the systolic, diastolic, and mean arterial pressures were 102.9 ± 1.76, 61.2 ± 0.92 and 74.8 ± 0.89 mmHg, respectively (Figure 2). Data from Figure 2 shows a transient drop in systolic blood pressure at 75 min and 120 min during the procedure with subsequent recovery. This is a difficult observation to explain as the event had a short duration and did not appear to have any deleterious effects to the pigs. It is possible the culmination of prolonged surgery, combination of anesthesia (isoflurane gas) and analgesics (remifentanil hydrochloride) affected the systolic blood pressure, but further investigations are needed to determine the mechanism(s) resulting in this observation. Importantly, these measured pressures were similar to arterial pressures observed in pigs anesthetized with either a combination of injectable synthetic narcotic and isoflurane gas or isoflurane gas alone29,30,31. The measured arterial blood gas components over 120 min are shown in Table 1 and include chemical parameters to evaluate acid base balance, hemoglobin content, and electrolyte concentrations. The values presented were within documented arterial blood pressure and clinical chemistry reference ranges for swine18,32,33,34; however a notable finding was the increased anion gap and reduced total hemoglobin at 120 min. These changes in values were likely associated with physiological changes that can occur during a substantive surgical procedure. Importantly, and in the context of arterial catheterization, the information provided underscores that accurate measures of arterial pressures and arterial blood chemistry are easily obtained from brachial artery catheterization.
Figure 1: Time requirement: Catheterization of the brachial artery in pigs. Results are expressed as mean ± SEM (n = 7). Solid bar = mean and shaded area = SEM.
Figure 2: Brachial arterial pressures in pigs. Systolic = systolic arterial pressure; Diastolic = diastolic arterial pressure; MAP = mean arterial pressure. Results are expressed as mean ± SEM (n = 7).
| Time (min) |
pH | HCO3 (mmol/L) |
AnGap (mmol/L) |
Base Excess (mmol/L) |
PCO2 (mmHg) |
Total Hb (g/dL) |
Na+ (mmol/L) |
K+ (mmol/L) |
Cl– (mmol/L) |
| 0 | 7.50 ± 0.03 | 24.8 ± 1.9 | 11.5 ± 1.1 | 3.0 ± 1.7 | 34.3 ± 3.2 | 13.1 ± 1.1 | 141.0 ± 1.1 | 4.5 ± 0.5 | 109.2 ± 1.5 |
| 120 | 7.47± 0.03 | 25.0 ± 2.7 | 14.0 ±1.2 | 2.0 ± 1.3 | 34.0 ± 3.9 | 10.3 ± 0.8 | 139.4 ± 0.6 | 5.0 ± 0.4 | 107.5 ± 0.6 |
Table 1: Brachial arterial blood measurements in pigs. Results are expressed as mean ± SEM (n = 7).
List of Materials
| 0.9% NaCl (Saline) Solution | EMRN | JB1322P | 1 x1 liter bag |
| 10% Lidocaine spray | AstraZeneca | DIN:02039508 / 1 x 50 ml bottle | |
| 10% Povidone-Iodine scrub | Purdue Pharma | 521232 | 1 x 500 ml bottle |
| 20 ga 1-inch angiocatheter | Becton Dickinson | 381433 | 1 x angiocatheter |
| 2-0 polyglactin suture (Vicryl) | Ethicon | J339H | 2-0 vicryl / 1 packet of suture |
| 2-0 polypropylene suture (Prolene) | Ethicon | 8833H | 2-0 prolene / 1 packet of suture |
| 22 ga 1-inch angiocatheter | Becton Dickinson | 381423 | 1 x angiocatheter |
| 9 ID mm endotracheal tube | Jorvet | J0835P | 1 x endotracheal tube |
| Arterial blood pressure IV line | Argon Medical Devices | 112411 | 1 x arterial blood pressure IV line |
| Disposable drapes | Halyard Sales LLC | 89731 | 4-8 x disposable drapes |
| Glycopyrrolate hydrochloride | Sandoz | DIN:02039508 / 1 x 20ml vial | |
| Isoflurane | Abbott Animal Health | 05260-5 | 1 x 250ml bottle |
| Kelly forceps-curved (14cm) | Stevens | 162-7-38 | 8-10 instruments |
| Ketamine hydrochloride | Vetoquinol | DIN:02374994 / 1 x 10ml vial | |
| Lactated Ringer's Solution | Hospira | 0409-7953-09 | 4 x1 liter bag |
| Metzenbaum scissors | Fine Science | 14518-18 | |
| Miller laryngoscope blade | Welch Allyn | 68044 | 182 mm length / 1 instrument |
| Nasal temperature probe | Surgivet | V3417 | 1 probe |
| Needle Drivers | Stevens | 162-V98-42 | 2 instruments |
| Q tip applicators | Fisher Scientific | 22-037-960 | 20-40 app |
| Remifentanil hydrochloride | TEVA | DIN:0234432 / 1 mg vial | |
| Surgivet advisor: Vital signs monitor | Surgivet | V9203 | 1 monitor |
| Weitlaner retractor | Stevens | 162-11-602 | 2 retractors |
| Xylazine hydrochloride | Bayer | DIN:02169606 1 x 50ml bottle |
Preparação do Laboratório
The video describes in detail the catheterization of the distal brachial artery in swine. This technique enables researchers to measure arterial blood pressure continuously and collect arterial blood samples to assess arterial blood gas measurements. Arterial blood pressures and arterial blood gases are important physiological parameters to monitor during experimental procedures. In swine, four common methods of arterial catheterization have been described, including catheterization of the carotid, femoral, auricular, and medial saphenous arteries. Each of these techniques have advantages, such as ease of access for the auricular artery, and disadvantages that include deep tissue dissection for carotid artery catheterization. The described alternative method of arterial catheterization in swine, the catheterization of the distal aspect of the brachial artery, is a rapid procedure that requires relatively minimal tissue dissection and provides information that is in line with data collected from other arterial catheterization sites. The procedure uses a medial approach along an oblique plane of the lower brachium, positioned between the olecranon and the flexor aspect of the elbow joint, and this approach allows researchers the major advantage of unimpeded freedom for procedures that involve the caudoventral, caudodorsal back, or hind limbs of the pig. Due to the location of the upper forelimb of the catheterized vessel and potential challenges of effective homeostasis following catheter removal from the artery, this technique may be limited to non-recovery procedures.
The video describes in detail the catheterization of the distal brachial artery in swine. This technique enables researchers to measure arterial blood pressure continuously and collect arterial blood samples to assess arterial blood gas measurements. Arterial blood pressures and arterial blood gases are important physiological parameters to monitor during experimental procedures. In swine, four common methods of arterial catheterization have been described, including catheterization of the carotid, femoral, auricular, and medial saphenous arteries. Each of these techniques have advantages, such as ease of access for the auricular artery, and disadvantages that include deep tissue dissection for carotid artery catheterization. The described alternative method of arterial catheterization in swine, the catheterization of the distal aspect of the brachial artery, is a rapid procedure that requires relatively minimal tissue dissection and provides information that is in line with data collected from other arterial catheterization sites. The procedure uses a medial approach along an oblique plane of the lower brachium, positioned between the olecranon and the flexor aspect of the elbow joint, and this approach allows researchers the major advantage of unimpeded freedom for procedures that involve the caudoventral, caudodorsal back, or hind limbs of the pig. Due to the location of the upper forelimb of the catheterized vessel and potential challenges of effective homeostasis following catheter removal from the artery, this technique may be limited to non-recovery procedures.
Procedimento
The video describes in detail the catheterization of the distal brachial artery in swine. This technique enables researchers to measure arterial blood pressure continuously and collect arterial blood samples to assess arterial blood gas measurements. Arterial blood pressures and arterial blood gases are important physiological parameters to monitor during experimental procedures. In swine, four common methods of arterial catheterization have been described, including catheterization of the carotid, femoral, auricular, and medial saphenous arteries. Each of these techniques have advantages, such as ease of access for the auricular artery, and disadvantages that include deep tissue dissection for carotid artery catheterization. The described alternative method of arterial catheterization in swine, the catheterization of the distal aspect of the brachial artery, is a rapid procedure that requires relatively minimal tissue dissection and provides information that is in line with data collected from other arterial catheterization sites. The procedure uses a medial approach along an oblique plane of the lower brachium, positioned between the olecranon and the flexor aspect of the elbow joint, and this approach allows researchers the major advantage of unimpeded freedom for procedures that involve the caudoventral, caudodorsal back, or hind limbs of the pig. Due to the location of the upper forelimb of the catheterized vessel and potential challenges of effective homeostasis following catheter removal from the artery, this technique may be limited to non-recovery procedures.