JOURNAL
OF SURGICAL
RESEARCH
21, 117.-119
Carotid Repeated W. KIRT
(1976)
Artery
Arterial
NICHOLS,
Transposition Pressure
M.D.,’
AND
for
Measurements
W. FORD
KEITZER,
M.D.2
Peripheral Vascular Laboratory, Department of Surgery, University of Missouri Medical Center, Columbia, Missouri 65201 and The Harry S. Truman Memorial Veterans Administration Hospital, Columbia, Missouri65201 Submitted
for publication
The technique for carotid loop formation has been used since Van Leersum first described it in 1911 [3]. A carotid loop is an excellent means to gain access to the carotid artery for chronic blood pressure measurements, drawing of arterial blood samples, and catheterization of the heart and great vessels. The carotid loop has found its widest application in animal experimentation involving hypertension. Originally, carotid loop blood pressure measurements were made using a specially designed sphygmomanometer cuff to occlude the artery and then noting the blood pressure with the reappearance of the Korotkoff sounds or by palpation. Recently, the use of the carotid loop to measure blood pressure by percutaneous needle puncture of the underlying artery has been popularized [2]. Comparison between this technique and the original method, in our lab, show the percutaneous technique is far more accurate and reproducible. We have abandoned the use of carotid loops in our studies of persistent, experimental hypertension in favor of bilateral carotid transposition because of recurrent problems with infection, loop necrosis, and carotid blowout with exsanguination of our experimental animal. In addition, the length of time between construction and use of a carotid loop is unfavorably long (20-30 days)
111. TECHNIQUE Dogs are anesthetized with intravenous Nembutal, 25 mg/kg, and an endotracheal ‘Assistant 2Professor
Professor of Surgery. of Surgery.
January
tube is inserted. The neck is hyperextended and then prepared by using any standard technique. A single midline incision approximately 10 cm long is made (Fig. 1A). The loose cervical skin including the platysma muscle is raised as a broad flap on either side of the incision exposing the strap muscles (Fig. 1B). An anterior approach between the sternothyroid and sternohyoid muscles is used on each side, and the carotid sheath is identified. The sheath is entered and the carotid artery is freed from the vagus nerve and internal jugular vein. A segment of artery approximately 8-10 cm in length is isolated and brought up between the sternohyoid and sternothyroid muscles. These muscles are then closed beneath the artery with a nonabsorbable suture leaving the carotid artery in a superficial position (Fig. lC, D). The skin flap is then sutured to the underlying fascia, both lateral and medial to the vessel, using an interrupted technique. This immobilizes the vessel and forms a subcutaneous tunnel for it (Fig. lE, F). The procedure is then repeated on the opposite side, and the incision is closed in layers using a subcuticular chromic suture for the skin (Fig. 1G). The preparation is usually ready for use in about lo- 13 days. Pressures are measured using a percutaneous needle puncture technique. A 22-gauge needle is attached to a Statham SP37 pressure transducer, and by palpation the artery is localized. The vessel is punctured and pressures are recorded on a direct writing recorder (Fig. 2). All pressures are recorded in unanesthetized erect dogs restrained loosely by the experimentor. After 117
Copyright All rights
@ 1976 by Academic Press, Inc. of reproduction in any form reserved.
12, 1976
118
JOURNAL
OF
SURGICAL
v
,
RESEARCH:
Carotid
VOL.
loops
21, NO.
2, AUGUST
1976
elevated
,/-‘ i
/ J! j,,,
FIG.
1 A-G.
Technique
for bilateral
transposition
of carotid
arteries
(see text for description).
NICHOLS
F ‘ICi. 2. Percutaneous tran sducer with attached
AND
KEITZER:
CAROTID
ARTERY
puncture technique. (A) Neck extended. Both carotids needle used for direct punctureof right carotid artery.
the pressure is recorded and the needle removed, digital pressure for 3-5 min controls bleeding. COMMENTS This technique was developed because of recurrent problems with the construction and maintenance of carotid loops in dogs. Advantages we have found using this technique compared with carotid loops include shorter delay between preparation and use, no problems with infection, necrosis, and carotid blowout, and a bilateral preparation allows one to alter the site of puncture each time. We have used this technique in more than 50 dogs over a 3-year period and find it to be superior to the carotid loop in our hands. All vessels have remained patent after repeated puncture. SUMMARY A technique for the preparation of animals to allow chronic, percutaneous recording of
119
TRANSPOSITION
visible
(arrows).
(B) Statham
SP. -37
arterial blood pressure is presented. We feel this method is superior to the carotid loop in our hands for the following reasons: (1) no problem with infection, necrosis of skin flaps, or carotid blowout has been encountered; (2) shorter delay (lo- 13 days compared to more than 20 days) between construction and use; (3) both carotids are prepared, giving one the option to alternate sides for pressure measurements, reducing the risk of occlusion by repeated punctures of one vessel. REFERENCES 1. Meier, M. D., and Long, D. M. Carotid artery loop for repeated catheterization of the left ventricle in dogs. Surgery 70:797, 197 1. 2. O’Brien, D. J., Chapman, W. H., Rudd, F. V., and McRoberts, J. W. Carotid artery loop methods of blood pressure measurement in the dog. J. Appl. Physiol. 30:161, 1971. 3. Van Leersum, E. C. Eine Method zur Erleichterung der Blutdruckmessung bei Tieren, Pfluger. Arch. Ges. Physiol. 142:377, 1911.
OF SURGICAL
RESEARCH
21, 117.-119
Carotid Repeated W. KIRT
(1976)
Artery
Arterial
NICHOLS,
Transposition Pressure
M.D.,’
AND
for
Measurements
W. FORD
KEITZER,
M.D.2
Peripheral Vascular Laboratory, Department of Surgery, University of Missouri Medical Center, Columbia, Missouri 65201 and The Harry S. Truman Memorial Veterans Administration Hospital, Columbia, Missouri65201 Submitted
for publication
The technique for carotid loop formation has been used since Van Leersum first described it in 1911 [3]. A carotid loop is an excellent means to gain access to the carotid artery for chronic blood pressure measurements, drawing of arterial blood samples, and catheterization of the heart and great vessels. The carotid loop has found its widest application in animal experimentation involving hypertension. Originally, carotid loop blood pressure measurements were made using a specially designed sphygmomanometer cuff to occlude the artery and then noting the blood pressure with the reappearance of the Korotkoff sounds or by palpation. Recently, the use of the carotid loop to measure blood pressure by percutaneous needle puncture of the underlying artery has been popularized [2]. Comparison between this technique and the original method, in our lab, show the percutaneous technique is far more accurate and reproducible. We have abandoned the use of carotid loops in our studies of persistent, experimental hypertension in favor of bilateral carotid transposition because of recurrent problems with infection, loop necrosis, and carotid blowout with exsanguination of our experimental animal. In addition, the length of time between construction and use of a carotid loop is unfavorably long (20-30 days)
111. TECHNIQUE Dogs are anesthetized with intravenous Nembutal, 25 mg/kg, and an endotracheal ‘Assistant 2Professor
Professor of Surgery. of Surgery.
January
tube is inserted. The neck is hyperextended and then prepared by using any standard technique. A single midline incision approximately 10 cm long is made (Fig. 1A). The loose cervical skin including the platysma muscle is raised as a broad flap on either side of the incision exposing the strap muscles (Fig. 1B). An anterior approach between the sternothyroid and sternohyoid muscles is used on each side, and the carotid sheath is identified. The sheath is entered and the carotid artery is freed from the vagus nerve and internal jugular vein. A segment of artery approximately 8-10 cm in length is isolated and brought up between the sternohyoid and sternothyroid muscles. These muscles are then closed beneath the artery with a nonabsorbable suture leaving the carotid artery in a superficial position (Fig. lC, D). The skin flap is then sutured to the underlying fascia, both lateral and medial to the vessel, using an interrupted technique. This immobilizes the vessel and forms a subcutaneous tunnel for it (Fig. lE, F). The procedure is then repeated on the opposite side, and the incision is closed in layers using a subcuticular chromic suture for the skin (Fig. 1G). The preparation is usually ready for use in about lo- 13 days. Pressures are measured using a percutaneous needle puncture technique. A 22-gauge needle is attached to a Statham SP37 pressure transducer, and by palpation the artery is localized. The vessel is punctured and pressures are recorded on a direct writing recorder (Fig. 2). All pressures are recorded in unanesthetized erect dogs restrained loosely by the experimentor. After 117
Copyright All rights
@ 1976 by Academic Press, Inc. of reproduction in any form reserved.
12, 1976
118
JOURNAL
OF
SURGICAL
v
,
RESEARCH:
Carotid
VOL.
loops
21, NO.
2, AUGUST
1976
elevated
,/-‘ i
/ J! j,,,
FIG.
1 A-G.
Technique
for bilateral
transposition
of carotid
arteries
(see text for description).
NICHOLS
F ‘ICi. 2. Percutaneous tran sducer with attached
AND
KEITZER:
CAROTID
ARTERY
puncture technique. (A) Neck extended. Both carotids needle used for direct punctureof right carotid artery.
the pressure is recorded and the needle removed, digital pressure for 3-5 min controls bleeding. COMMENTS This technique was developed because of recurrent problems with the construction and maintenance of carotid loops in dogs. Advantages we have found using this technique compared with carotid loops include shorter delay between preparation and use, no problems with infection, necrosis, and carotid blowout, and a bilateral preparation allows one to alter the site of puncture each time. We have used this technique in more than 50 dogs over a 3-year period and find it to be superior to the carotid loop in our hands. All vessels have remained patent after repeated puncture. SUMMARY A technique for the preparation of animals to allow chronic, percutaneous recording of
119
TRANSPOSITION
visible
(arrows).
(B) Statham
SP. -37
arterial blood pressure is presented. We feel this method is superior to the carotid loop in our hands for the following reasons: (1) no problem with infection, necrosis of skin flaps, or carotid blowout has been encountered; (2) shorter delay (lo- 13 days compared to more than 20 days) between construction and use; (3) both carotids are prepared, giving one the option to alternate sides for pressure measurements, reducing the risk of occlusion by repeated punctures of one vessel. REFERENCES 1. Meier, M. D., and Long, D. M. Carotid artery loop for repeated catheterization of the left ventricle in dogs. Surgery 70:797, 197 1. 2. O’Brien, D. J., Chapman, W. H., Rudd, F. V., and McRoberts, J. W. Carotid artery loop methods of blood pressure measurement in the dog. J. Appl. Physiol. 30:161, 1971. 3. Van Leersum, E. C. Eine Method zur Erleichterung der Blutdruckmessung bei Tieren, Pfluger. Arch. Ges. Physiol. 142:377, 1911.
