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Intermittent Venting of the Left Ventricle
Intermittent Venting of the Left Ventricle Ian M. Ross, C.P., and Terrill E. Theman, F.R.C.S.(C)
ABSTRACT A technique is described for intermit- ter) tubing connected to an air-bleed valve and tent decompression of the left ventricle. This method a standard vacuum gauge. Prior to the start of provides all of the advantages of left ventricular cardiopulmonary bypass, the vent tubing is venting while eliminating the hazards. The tech- clamped on the patient side of the Y connector nique is most advantageous in coronary artery oper- and the pump is set at one-third speed. The air-bleed valve is then adjusted to maintain a ations, vacuum of 120 torr, after which the clamp is reAs coronary artery bypass operations become moved. This prevents collapse of the vent, and more commonplace, the surgical techniques the air-bleed valve allows adjustment for more are, in general, being standardized. One area of or less venting. It is our technique to connect the vent to controversy persists, however: the necessity to decompress the left ventricle [l]. There are gentle suction soon after the initiation of carsome who advocate routine venting of the left diopulmonary bypass to reduce left ventricular ventricle [2,31,while others maintain that there work. During this period the blood cardiois no need for such a technique [4-61.Most sur- plegia solution is cooled and the saphenous geons who do not use left ventricular vents vein graft is prepared. Following aortic cross-clamping, the cold argue that venting prolongs the operation, damages the myocardium, and risks the intro- blood cardioplegia solution is infused into the duction of air into the aortic root 14-91. aortic root and the left ventricular intracaviNevertheless, it is difficult to ignore the pio- tary pressure is monitored by the perfusionist. neering work of Buckberg [2,31 regarding the Suction is not applied to the vent unless the favorable effect of venting on left ventricular left ventricular pressure exceeds 15 torr. This method permits the aortic root and left venwork and subendocardial blood flow. tricular cavity to remain fluid filled and free from entrained air. Method Once all of the distal coronary artery anasOnce cardiopulmonary bypass is established in the routine manner, the left ventricle is vented tomoses have been completed, the aortic crosswith a Sarns curved left heart vent catheter clamp is removed and the left ventricular vent is passed from the right superior pulmonary vein attached to gentle suction. With reperfusion of across the mitral valve into the left ventricle. A the coronary bed, spontaneous normal cardiac side port on the vent is attached to a pressure activity usually follows, thus creating a vented, transducer while the main channel is connected beating heart. A partial occlusion clamp is used to a roller pump (Fig 1). for the proximal graft anastomoses. As Figure 2 illustrates, the vent tubing has a Y After the proximal coronary anastomoses junction before it enters the roller pump. The have been completed and air bubbles have second limb of the Y consists of a 50.8 cm (20 been removed from the vein grafts, the anasinch) piece of 0.6 cm (0.25 inch) (inner diame- tomoses all are carefully examined and hemostasis is assured. With the patient at normothermia and a satisfactory cardiac rhythm, From the Division of Cardiac Surgery, Health Sciences the vent is turned off and removed. A left atrial Centre, Memorial University of Newfoundland, St. John's, line is routinely inserted at this stage to enable Newfoundland, Canada. accurate monitoring of the left heart filling Accepted for publication Mar 3, 1980. pressures during weaning from cardiopulmoAddress reprint requests to Dr. Theman, Division of Cardiac Surgery, Memorial University of Newfoundland, St. nary bypass. This left atrial line is usually left in place for the first 24 hours postoperatively. John's, Newfoundland, Canada AlB 3V6. 379 0003-4975/81/040379-02$01.25 @ 1980 by The Society of Thoracic Surgeons
380 The Annals of Thoracic Surgery Vol 31 No 4
April 1981
u'
R SUPERIOR PULMONARY VEIN
II:no/
Fig 1 . The left ventricular vent catheter properly positioned. The side port for pressure measurement and the main line for suction to the pump are diagramed.
r
ventricle. In our experience of more than 100 patients having open-heart operation, the use of a left ventricular vent inserted through the pulmonary vein does not prolong the operative procedure by more than five minutes, and has never resulted in myocardial injury. By reducing left ventricular work, this technique creates a favorable myocardial oxygen supplyldemand ratio both before aortic crossclamping as well as after the removal of the cross-clamp [31. The provision of a vented beating, nonworking left ventricle following removal of the cross-clamp offers a n opportunity to repay any oxygen debt incurred during the anoxic phase [ll. The technique is easy to use and does not involve any methods not already employed by the majority of cardiac surgeons. For more than a year, its efficacy and safety have been demonstrated i n our patient population in whom it has been used.
References 1. Arom KV, Vinas JF, Fewel JE, et al: Is a left
2. 3.
4.
5. 6.
Fig 2. The vent suction system.
7.
Comment The use of intermittent left ventricular venting
8.
offers the advantage of left ventricular decompression in both the beating heart and in the 9. arrested left ventricle without the risk of entrainment of air into the aortic root and left
ventricular vent necessary during cardiopulmonary bypass? Ann Thorac Surg 24:566, 1977 Buckberg GD: The importance of venting the left ventricle (editorial). Ann Thorac Surg 20:488,1975 Hottenrott C, Buckberg GD: Studies of the effects of ventricular fibrillation on the adequacy of regional myocardial flow: 11. Effects of ventricular distention. J Thorac Cardiovasc Surg 68:626, 1974 Okies JE, Phillips SJ, Crenshaw R, Starr A: "Novent" technique of coronary artery bypass. Ann Thorac Surg 19:191, 1975 Salerno TA, Charrette EJP: Elimination of venting in coronary artery surgery. Ann Thorac Surg 27:340, 1979 Zwart HHJ, Brainard JZ, DeWall RA: Ventricular fibrillation without left ventricular venting: observations in humans. Ann Thorac Surg 20:418, 1975 Harlan BJ, Kyger ER 111, Reul GJ Jr, Cooley DA Needle suction of the aorta for left heart decompression during aortic cross-clamping. Ann Thorac Surg 23:259, 1977 Heimbecker RO, McKenzie FN: A new approach to left heart decompression. Ann Thorac Surg 21:456, 1976 Lajos TZ, Lee AB, Schimert G: Decompression of the heart with siphon drainage. Ann Thorac Surg 25:454, 1978
ABSTRACT A technique is described for intermit- ter) tubing connected to an air-bleed valve and tent decompression of the left ventricle. This method a standard vacuum gauge. Prior to the start of provides all of the advantages of left ventricular cardiopulmonary bypass, the vent tubing is venting while eliminating the hazards. The tech- clamped on the patient side of the Y connector nique is most advantageous in coronary artery oper- and the pump is set at one-third speed. The air-bleed valve is then adjusted to maintain a ations, vacuum of 120 torr, after which the clamp is reAs coronary artery bypass operations become moved. This prevents collapse of the vent, and more commonplace, the surgical techniques the air-bleed valve allows adjustment for more are, in general, being standardized. One area of or less venting. It is our technique to connect the vent to controversy persists, however: the necessity to decompress the left ventricle [l]. There are gentle suction soon after the initiation of carsome who advocate routine venting of the left diopulmonary bypass to reduce left ventricular ventricle [2,31,while others maintain that there work. During this period the blood cardiois no need for such a technique [4-61.Most sur- plegia solution is cooled and the saphenous geons who do not use left ventricular vents vein graft is prepared. Following aortic cross-clamping, the cold argue that venting prolongs the operation, damages the myocardium, and risks the intro- blood cardioplegia solution is infused into the duction of air into the aortic root 14-91. aortic root and the left ventricular intracaviNevertheless, it is difficult to ignore the pio- tary pressure is monitored by the perfusionist. neering work of Buckberg [2,31 regarding the Suction is not applied to the vent unless the favorable effect of venting on left ventricular left ventricular pressure exceeds 15 torr. This method permits the aortic root and left venwork and subendocardial blood flow. tricular cavity to remain fluid filled and free from entrained air. Method Once all of the distal coronary artery anasOnce cardiopulmonary bypass is established in the routine manner, the left ventricle is vented tomoses have been completed, the aortic crosswith a Sarns curved left heart vent catheter clamp is removed and the left ventricular vent is passed from the right superior pulmonary vein attached to gentle suction. With reperfusion of across the mitral valve into the left ventricle. A the coronary bed, spontaneous normal cardiac side port on the vent is attached to a pressure activity usually follows, thus creating a vented, transducer while the main channel is connected beating heart. A partial occlusion clamp is used to a roller pump (Fig 1). for the proximal graft anastomoses. As Figure 2 illustrates, the vent tubing has a Y After the proximal coronary anastomoses junction before it enters the roller pump. The have been completed and air bubbles have second limb of the Y consists of a 50.8 cm (20 been removed from the vein grafts, the anasinch) piece of 0.6 cm (0.25 inch) (inner diame- tomoses all are carefully examined and hemostasis is assured. With the patient at normothermia and a satisfactory cardiac rhythm, From the Division of Cardiac Surgery, Health Sciences the vent is turned off and removed. A left atrial Centre, Memorial University of Newfoundland, St. John's, line is routinely inserted at this stage to enable Newfoundland, Canada. accurate monitoring of the left heart filling Accepted for publication Mar 3, 1980. pressures during weaning from cardiopulmoAddress reprint requests to Dr. Theman, Division of Cardiac Surgery, Memorial University of Newfoundland, St. nary bypass. This left atrial line is usually left in place for the first 24 hours postoperatively. John's, Newfoundland, Canada AlB 3V6. 379 0003-4975/81/040379-02$01.25 @ 1980 by The Society of Thoracic Surgeons
380 The Annals of Thoracic Surgery Vol 31 No 4
April 1981
u'
R SUPERIOR PULMONARY VEIN
II:no/
Fig 1 . The left ventricular vent catheter properly positioned. The side port for pressure measurement and the main line for suction to the pump are diagramed.
r
ventricle. In our experience of more than 100 patients having open-heart operation, the use of a left ventricular vent inserted through the pulmonary vein does not prolong the operative procedure by more than five minutes, and has never resulted in myocardial injury. By reducing left ventricular work, this technique creates a favorable myocardial oxygen supplyldemand ratio both before aortic crossclamping as well as after the removal of the cross-clamp [31. The provision of a vented beating, nonworking left ventricle following removal of the cross-clamp offers a n opportunity to repay any oxygen debt incurred during the anoxic phase [ll. The technique is easy to use and does not involve any methods not already employed by the majority of cardiac surgeons. For more than a year, its efficacy and safety have been demonstrated i n our patient population in whom it has been used.
References 1. Arom KV, Vinas JF, Fewel JE, et al: Is a left
2. 3.
4.
5. 6.
Fig 2. The vent suction system.
7.
Comment The use of intermittent left ventricular venting
8.
offers the advantage of left ventricular decompression in both the beating heart and in the 9. arrested left ventricle without the risk of entrainment of air into the aortic root and left
ventricular vent necessary during cardiopulmonary bypass? Ann Thorac Surg 24:566, 1977 Buckberg GD: The importance of venting the left ventricle (editorial). Ann Thorac Surg 20:488,1975 Hottenrott C, Buckberg GD: Studies of the effects of ventricular fibrillation on the adequacy of regional myocardial flow: 11. Effects of ventricular distention. J Thorac Cardiovasc Surg 68:626, 1974 Okies JE, Phillips SJ, Crenshaw R, Starr A: "Novent" technique of coronary artery bypass. Ann Thorac Surg 19:191, 1975 Salerno TA, Charrette EJP: Elimination of venting in coronary artery surgery. Ann Thorac Surg 27:340, 1979 Zwart HHJ, Brainard JZ, DeWall RA: Ventricular fibrillation without left ventricular venting: observations in humans. Ann Thorac Surg 20:418, 1975 Harlan BJ, Kyger ER 111, Reul GJ Jr, Cooley DA Needle suction of the aorta for left heart decompression during aortic cross-clamping. Ann Thorac Surg 23:259, 1977 Heimbecker RO, McKenzie FN: A new approach to left heart decompression. Ann Thorac Surg 21:456, 1976 Lajos TZ, Lee AB, Schimert G: Decompression of the heart with siphon drainage. Ann Thorac Surg 25:454, 1978