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AN IMPROVED CORONARY ARTERY PERFUSION CANNULA
A N IMPROVED C O R O N A R Y ARTERY PERFUSION C A N N U L A Brian ]. King, M.B., B. Chir.,* Rochester,
Minn.
A
CORONARY perfusion cannula has been developed at the Mayo Clinic which has proved superior to each of the various types previously employed. Cannulas of the new type are simply and quickly inserted into one or both coronary ostia, are free of leakage, require no further attention following insertion, are selfretaining, and do not restrict or encumber exposure of the operative area.
Fig. 1.—Five millimeter round-tipped cannula and cuff.
A coronary perfusion flow of approximately 150 ml. of blood per minute to each coronary vessel requires a pressure in the perfusion line of 50 to 300 mm. of mercury, depending upon the size of the vessel and the length and diameter of the tubing used. This pressure is a source of energy which is utilized to expand a small latex cuff attached to the tip of a stainless steel cannula (Fig. 1). The metal tip is attached to Tygon tubing, the external diameter of which is identical with that of the maximal over-all diameter of the tip. The shank of the cannula has two holes which communicate with the lumen. After the Tygon tubing is fitted to the shank, holes are burned in the tubing to correspond with the holes in the shank. An extremely thin latex cuff is fitted over the tip of the cannula and the attached Tygon tubing so that when blood flows through the cannula the pressure in the tubing is transmitted via the holes in the shank and in the Tygon tubing to the walls of the cuff. From the Mayo Clinic and Mayo Foundation, Rochester, Minn. Work on which this paper is based was carried out under the direction of Dr. Dwight C. McGoon. Received for publication Nov. 1, 1962. •Fellow in Surgery. 667
668
KING
J. Thoracic and Cardiovas. Surg.
The diameter of the lumen at the tip of the cannula is purposely reduced in comparison with the diameter of the lumen of the shank, thereby creating a fall in pressure across the tip when blood is flowing. The pressure within the cuff is thus identical with that in the Tygon tubing and is always higher than the blood pressure within the coronary vessel itself. The effect of this difference in pressure is to ensure that, as long as blood is flowing through the cannula, the cuff expands to the limits of the coronary lumen, seals off all blood leaks, and, by friction upon the walls of the vessel, holds the cannula in place.
Fig. 2.—Upper:
5 mm. cannula with tapered tip and cuff attached to Tygon tubing. 5 mm. cannula with round tip.
*
JwaSKiSty
*.-T'.V*».r
Fig. 3.—Special device for assembling cuffs on metal cannula.
Lower'
Vol. 45, No. 5 May, 1963
CORONARY ARTERY P E R F U S I O N CANNULA
669 VVU
There are two types of metal cannula tips, one rounded and the other tapered (Fig. 2). The rounded tip (5 mm. diameter) is preferred in most instances because it avoids injury to the intima of the vessel. The cuff is extremely thin walled (2/1000 to 4/1000 inch) yet does not overdistend, since all pressure within the cuff is ultimately assumed by the wall of the coronary vessel. A special device has been designed to allow correct placement of the cuffs over the metal tips with minimal risk of tearing or puncturing the cuffs (Fig. 3). It is essential that sterilization of the tubing, tips, and cuffs be effected by the use of ethylene oxide. These cuffed eannulas, which are available* in the rounded-tip pattern, either as separate items or as complete sets of eannulas, cuffs and the necessary instruments for fitting the cuffs, have been used successfully by the cardiac surgeons of the Mayo Clinic for 8 months. The technique of coronary artery perfusion will be the subject of another report (McGoon and associates, unpublished data 1 ). The author wishes to acknowledge the encouragement and stimulus afforded by his association with the cardiac surgeons of the Mayo Clinic, and the facilities made available by them, which led to the development of the cannula described. REFERENCE
1. McGoon, D. C , King, B. J., and Albertal, G.: Technique for Coronary Perfusion. published data.)
•From V. Mueller and Co., Rochester, Minnesota.
(Un-
Minn.
A
CORONARY perfusion cannula has been developed at the Mayo Clinic which has proved superior to each of the various types previously employed. Cannulas of the new type are simply and quickly inserted into one or both coronary ostia, are free of leakage, require no further attention following insertion, are selfretaining, and do not restrict or encumber exposure of the operative area.
Fig. 1.—Five millimeter round-tipped cannula and cuff.
A coronary perfusion flow of approximately 150 ml. of blood per minute to each coronary vessel requires a pressure in the perfusion line of 50 to 300 mm. of mercury, depending upon the size of the vessel and the length and diameter of the tubing used. This pressure is a source of energy which is utilized to expand a small latex cuff attached to the tip of a stainless steel cannula (Fig. 1). The metal tip is attached to Tygon tubing, the external diameter of which is identical with that of the maximal over-all diameter of the tip. The shank of the cannula has two holes which communicate with the lumen. After the Tygon tubing is fitted to the shank, holes are burned in the tubing to correspond with the holes in the shank. An extremely thin latex cuff is fitted over the tip of the cannula and the attached Tygon tubing so that when blood flows through the cannula the pressure in the tubing is transmitted via the holes in the shank and in the Tygon tubing to the walls of the cuff. From the Mayo Clinic and Mayo Foundation, Rochester, Minn. Work on which this paper is based was carried out under the direction of Dr. Dwight C. McGoon. Received for publication Nov. 1, 1962. •Fellow in Surgery. 667
668
KING
J. Thoracic and Cardiovas. Surg.
The diameter of the lumen at the tip of the cannula is purposely reduced in comparison with the diameter of the lumen of the shank, thereby creating a fall in pressure across the tip when blood is flowing. The pressure within the cuff is thus identical with that in the Tygon tubing and is always higher than the blood pressure within the coronary vessel itself. The effect of this difference in pressure is to ensure that, as long as blood is flowing through the cannula, the cuff expands to the limits of the coronary lumen, seals off all blood leaks, and, by friction upon the walls of the vessel, holds the cannula in place.
Fig. 2.—Upper:
5 mm. cannula with tapered tip and cuff attached to Tygon tubing. 5 mm. cannula with round tip.
*
JwaSKiSty
*.-T'.V*».r
Fig. 3.—Special device for assembling cuffs on metal cannula.
Lower'
Vol. 45, No. 5 May, 1963
CORONARY ARTERY P E R F U S I O N CANNULA
669 VVU
There are two types of metal cannula tips, one rounded and the other tapered (Fig. 2). The rounded tip (5 mm. diameter) is preferred in most instances because it avoids injury to the intima of the vessel. The cuff is extremely thin walled (2/1000 to 4/1000 inch) yet does not overdistend, since all pressure within the cuff is ultimately assumed by the wall of the coronary vessel. A special device has been designed to allow correct placement of the cuffs over the metal tips with minimal risk of tearing or puncturing the cuffs (Fig. 3). It is essential that sterilization of the tubing, tips, and cuffs be effected by the use of ethylene oxide. These cuffed eannulas, which are available* in the rounded-tip pattern, either as separate items or as complete sets of eannulas, cuffs and the necessary instruments for fitting the cuffs, have been used successfully by the cardiac surgeons of the Mayo Clinic for 8 months. The technique of coronary artery perfusion will be the subject of another report (McGoon and associates, unpublished data 1 ). The author wishes to acknowledge the encouragement and stimulus afforded by his association with the cardiac surgeons of the Mayo Clinic, and the facilities made available by them, which led to the development of the cannula described. REFERENCE
1. McGoon, D. C , King, B. J., and Albertal, G.: Technique for Coronary Perfusion. published data.)
•From V. Mueller and Co., Rochester, Minnesota.
(Un-