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PRESSURE-PERFUSION CANNULA
PRESSURE-PERFUSION
CANNULA
A Simplified Method of Monitoring Central Arterial Pressure During Perfusion Joe D. Morris, M.D., and Edward B. Diethrich, M.D., Ann Arbor,
Mich.
T
HE value of monitoring central arterial pressures during cardiopulmonary bypass is well recognized. The technical problems involved, however, may at times be frustrating and time consuming. For this reason, a femoral artery perfusion cannula has been designed which permits simultaneous recording of central arterial pressure during perfusion. The major feature of the cannula is a sidearm through which a small bore arterial catheter may be introduced and passed by way of the main lumen of the perfusion cannula into the abdominal aorta. Clinical experience with this femoral artery pressure-perfusion cannula* has demonstrated that it provides a dependable and simplified method of monitoring central arterial pressure.
PRESSURE - PERFUSION
CANNULA
Fig. 1.—Pressure-perfusion
cannula.
The bayonet-shaped cannula (Fig. 1) is constructed entirely of stainless steel with special attention to highly polished edges and central bore. The upper edge of the cannula tip projects forward producing a reverse bevel and permitting easier introduction into the arterial lumen. The manifold Prom The St. Joseph Mercy Hospital Surgical Research Laboratory, and the Department of Surgery, The University of Michigan Medical Center, Ann Arbor, Mich. Received for publication May 2, 1961. •Available from Sarns, Inc., 1401 Hewett Drive, Ann Arbor, Mich. 822
Vol. 43, No. 6 June, 1962
P R E S S U R E - P E R F U S I O N GANNULA
823
assembly attached to the proximal portion of the bayonet tube has a tapered tubing connection with securing nut. It is impossible for the Tygon tubing to slip from the cannula once the nut is tightened. The knurling on the nut and the flat manifold assembly aid in securing the Tygon-cannula connection. A % 4 inch hole through the manifold body permits passage of a 2-0 silk skin suture. This allows the cannula to be secured firmly to the skin preventing possible movement during the perfusion. The sidearm projecting from the manifold assembly has a central bore communicating with the lumen of the bayonet tube. A stylet and rubber sealer prevent loss of blood during cannulation. "When the stylet is removed, a nylon catheter with a swedged adaptor can be threaded through the bayonet tube and up into the aorta. The adaptor makes a blood-tight seal in the sidearm. The steps involved in using the pressure-perfusion cannula are shown in Pig. 2. The artery is isolated and cannulated in the standard manner. The stylet in the sidearm prevents leakage of blood during cannulation (A).
Fig. 2.—Steps involved in using pressure-perfusion cannula A, Perfusion cannula in position in femoral artery. B, stylet removed from sidearm and nylon catheter being threaded into abdominal aorta. C, Catheter connected to pressure transducer by three-way stopcock and connecting tubing.
Once the cannula has been secured in place, attention is turned to estab lishing the pressure circuit. When the stylet is removed, the opening in the rubber sealer is closed by applying pressure between the thumb and index finger, thus eliminating any blood loss. The nylon catheter is then threaded through the sealer and sidearm into the artery itself (B). Again, pressure on the sealer prevents significant blood leakage while the catheter is being threaded. The adaptor fits tightly into the sidearm which assures a blood-tight connection even under high pressure conditions. The length of the catheter must be sufficient to insure its placement in the abdominal aorta.
MOEEIS AND D1ETHRICH
824
J. Thoracic and Cardiovas. Surg.
At the conclusion of the bypass, the catheter and cannula are removed in reverse order. Should continuous monitoring of the pressure be desired following removal of the cannula, the nylon catheter can be reintroduced through the suture line of the femoral arteriotomy. manifold assembly
tygon tube with securing nut
WWWF^1—
Kk,*-*«alln8
nylon catheter with adapter
nut
@k
Fig. 3.—This drawing depicts the the substitution of the threaded sealing nut for the rubber sealer and stylet as explained in the Addendum. ADDENDUM Since the submission of this article, design of the cannula has been refined by substi tuting a locking nut for the rubber sealer and stylet (Fig. 3 ) . This nut permits the nylon pressure catheter to be threaded through a small hole in the top of the nut. As the nut is tightened on the side arm, an enclosed Silastic washer provides a water-tight seal on the catheter. This permits the pressure catheter to be advanced or withdrawn to any desired position. The tip of the monitoring catheter may be introduced through the sealing nut for several inches and secured prior to introducing the cannula into the femoral artery, simpli fying the introduction of the catheter. When the cannula is properly positioned, the nut may be loosened and the catheter advanced to the desired level in the aorta. Following withdrawal of the catheter from the cannula, tightening the sealing nut will seal the side arm and no stylet is necessary.
CANNULA
A Simplified Method of Monitoring Central Arterial Pressure During Perfusion Joe D. Morris, M.D., and Edward B. Diethrich, M.D., Ann Arbor,
Mich.
T
HE value of monitoring central arterial pressures during cardiopulmonary bypass is well recognized. The technical problems involved, however, may at times be frustrating and time consuming. For this reason, a femoral artery perfusion cannula has been designed which permits simultaneous recording of central arterial pressure during perfusion. The major feature of the cannula is a sidearm through which a small bore arterial catheter may be introduced and passed by way of the main lumen of the perfusion cannula into the abdominal aorta. Clinical experience with this femoral artery pressure-perfusion cannula* has demonstrated that it provides a dependable and simplified method of monitoring central arterial pressure.
PRESSURE - PERFUSION
CANNULA
Fig. 1.—Pressure-perfusion
cannula.
The bayonet-shaped cannula (Fig. 1) is constructed entirely of stainless steel with special attention to highly polished edges and central bore. The upper edge of the cannula tip projects forward producing a reverse bevel and permitting easier introduction into the arterial lumen. The manifold Prom The St. Joseph Mercy Hospital Surgical Research Laboratory, and the Department of Surgery, The University of Michigan Medical Center, Ann Arbor, Mich. Received for publication May 2, 1961. •Available from Sarns, Inc., 1401 Hewett Drive, Ann Arbor, Mich. 822
Vol. 43, No. 6 June, 1962
P R E S S U R E - P E R F U S I O N GANNULA
823
assembly attached to the proximal portion of the bayonet tube has a tapered tubing connection with securing nut. It is impossible for the Tygon tubing to slip from the cannula once the nut is tightened. The knurling on the nut and the flat manifold assembly aid in securing the Tygon-cannula connection. A % 4 inch hole through the manifold body permits passage of a 2-0 silk skin suture. This allows the cannula to be secured firmly to the skin preventing possible movement during the perfusion. The sidearm projecting from the manifold assembly has a central bore communicating with the lumen of the bayonet tube. A stylet and rubber sealer prevent loss of blood during cannulation. "When the stylet is removed, a nylon catheter with a swedged adaptor can be threaded through the bayonet tube and up into the aorta. The adaptor makes a blood-tight seal in the sidearm. The steps involved in using the pressure-perfusion cannula are shown in Pig. 2. The artery is isolated and cannulated in the standard manner. The stylet in the sidearm prevents leakage of blood during cannulation (A).
Fig. 2.—Steps involved in using pressure-perfusion cannula A, Perfusion cannula in position in femoral artery. B, stylet removed from sidearm and nylon catheter being threaded into abdominal aorta. C, Catheter connected to pressure transducer by three-way stopcock and connecting tubing.
Once the cannula has been secured in place, attention is turned to estab lishing the pressure circuit. When the stylet is removed, the opening in the rubber sealer is closed by applying pressure between the thumb and index finger, thus eliminating any blood loss. The nylon catheter is then threaded through the sealer and sidearm into the artery itself (B). Again, pressure on the sealer prevents significant blood leakage while the catheter is being threaded. The adaptor fits tightly into the sidearm which assures a blood-tight connection even under high pressure conditions. The length of the catheter must be sufficient to insure its placement in the abdominal aorta.
MOEEIS AND D1ETHRICH
824
J. Thoracic and Cardiovas. Surg.
At the conclusion of the bypass, the catheter and cannula are removed in reverse order. Should continuous monitoring of the pressure be desired following removal of the cannula, the nylon catheter can be reintroduced through the suture line of the femoral arteriotomy. manifold assembly
tygon tube with securing nut
WWWF^1—
Kk,*-*«alln8
nylon catheter with adapter
nut
@k
Fig. 3.—This drawing depicts the the substitution of the threaded sealing nut for the rubber sealer and stylet as explained in the Addendum. ADDENDUM Since the submission of this article, design of the cannula has been refined by substi tuting a locking nut for the rubber sealer and stylet (Fig. 3 ) . This nut permits the nylon pressure catheter to be threaded through a small hole in the top of the nut. As the nut is tightened on the side arm, an enclosed Silastic washer provides a water-tight seal on the catheter. This permits the pressure catheter to be advanced or withdrawn to any desired position. The tip of the monitoring catheter may be introduced through the sealing nut for several inches and secured prior to introducing the cannula into the femoral artery, simpli fying the introduction of the catheter. When the cannula is properly positioned, the nut may be loosened and the catheter advanced to the desired level in the aorta. Following withdrawal of the catheter from the cannula, tightening the sealing nut will seal the side arm and no stylet is necessary.