mitral valve replacement

1. Mitral stenosis, severe calcification of the valve. 2. Mitral stenosis, severe valve contracture, heavy lesions under the valve, can not be repaired by the formation method. 3. Mitral stenosis and insufficiency, the latter can not be resolved with a plastic surgery. 4. Simple mitral regurgitation, can not be corrected with plastic surgery. Treatment of diseases: mitral stenosis mitral regurgitation Indication 1. Mitral stenosis, severe calcification of the valve. 2. Mitral stenosis, severe valve contracture, heavy lesions under the valve, can not be repaired by the formation method. 3. Mitral stenosis and insufficiency, the latter can not be resolved with a plastic surgery. 4. Simple mitral regurgitation, can not be corrected with plastic surgery. Contraindications Patients with symptomatic moderate or severe mitral stenosis* with moderate to severe mitral regurgitation should undergo mitral valve replacement unless a surgical procedure can be performed. Preoperative preparation 1. Eliminate all infected lesions. 2. Correct malnutrition, anemia, and liver, kidney, and other organ dysfunction. 3. Correct heart failure or put the patient in the best possible condition. 4. Stop the digitalis and diuretics 48 hours before surgery. 5. Use an ordinary diet 1 week before surgery to adjust the electrolyte balance. If the patient takes long-term diuretics, the oral potassium chloride should be increased in the first week before surgery to overcome the deficiency of potassium in the body. 6. Start antibiotics with antibiotics on the 3rd day before surgery. Give a dose of antibiotics when you use the medicine before surgery. 7. In severe cases, glucose, insulin and potassium chloride solution (gik) were intravenously administered 1 week before surgery to protect the myocardium. 8. Psychotherapy should be performed on patients before surgery to eliminate concerns and enhance cooperation between doctors and patients. Let the patient understand the various situations that may occur during the operation to facilitate the patient's active cooperation. 9. Stop diuretics 24 to 48 hours before surgery. Surgical procedure 1. Incision and establishment of extracorporeal circulation 1. Incision: The sternal median incision is a standard extracorporeal circulation open heart surgery incision, which is well exposed and suitable for cardiac surgery in any part. The incision was slightly from the sternal notch and reached about 5 cm below the xiphoid. 2. Saw the sternum: Cut the sternal periosteum with an electric knife along the center, and separate the sternal incision to the sternum; then dissect the xiphoid and separate the posterior sternal space. After the xiphoid is removed, the sternum is sawn along the midline with a wind (electric) saw. The periosteum is electrocoagulated to stop bleeding, and the sternum is stopped by bone wax. 3. Cut the happy bag: cut the happy bag in the middle of the line, get the ascending aorta reflexed part, release the diaphragm, and cut the lower part of the incision to the side to facilitate the exposure. After that, the pericardial margin is sutured to the soft tissue outside the sternum, and the sternum is opened with a spreader to reveal the heart. 4. Extracardiac exploration: Exploring the size, tension, and tremor of the aorta, pulmonary artery, left and right atrium, left and right ventricles, superior and inferior vena cava, and pulmonary veins. Also check for the presence of left superior vena cava and other abnormalities that can be found outside the heart. 5. Establish extracorporeal circulation (1) Vena cava strap: first separate the gap between the aorta and the pulmonary artery, lift the aortic band, pull the band on the ascending aorta to the left, reveal the inside of the superior vena cava, and use the right angle pliers to wrap around the inside of the superior vena cava. After the strap. In the same way, the lower vena cava was placed around the inferior vena cava with a lower lumen. (2) Arterial intubation: At the distal end of the ascending aorta, the concentric purse is sutured with the 7th line, and the blood vessels are not penetrated, and are sutured in the adventitia of the aorta, and the opening of the purse line is one by one. Put the purse string into the hemostatic device to stop bleeding and fix when intubating. The outer membrane of the central portion of the purse is removed. After injecting heparin into the right atrial appendage (3mg/kg), use a small round (tip) blade to cut a small incision in the center of the purse, which is slightly smaller than the diameter of the arterial cannula. When the blade is withdrawn, the artery cannula is sent into the ascending aortic incision. Tighten the hemostats of the two purse lines and secure the arterial cannula to the hemostat with a thick wire. Finally, the arterial cannula is fixed on the edge of the incision or the petiole of the distractor, and the cannula is connected to the artificial heart-lung machine. (3) Cavernous vein cannulation: a purse string is sutured in the right atrial appendage and the right atrium, and a hemostatic device is placed, and then the incision is inserted into the superior and inferior vena cava cannula (generally inserted through the atrial appendage) to tighten the hemostat. A 2 to 3 mm atrial appendage and atrial wall below the incision were ligated around the cannula with a thick wire, and the upper and lower lumen cannula was fixed by the ligature to prevent slipping. Connect the upper and lower lumen cannula to the artificial heart-lung machine. (4) Cold heart cardioplegic perfusion cannula: a suture was placed on the anterior lateral membrane of the ascending aorta and placed in a hemostat. The cold heart cardioplegia is filled with the needle and the gas is inserted into the central part of the sacral suture into the ascending aorta. The hemostasis is tightened, and the cannula and the hemostat are fixed together by thick lines. Connect the cannula to the infusion device. (5) Left heart drainage cannula: You can choose one of the following: Left atrial drainage: a large suture suture at the junction of the right upper pulmonary vein root and the left atrium, with a hemostat. After cutting a small opening in the fistula suture, insert the left atrial drainage tube into the left atrium and tighten. The hemostat is ligated with a thick wire and the drainage tube is fixed to the hemostat. Connect the drainage tube to the artificial heart-lung machine. Left ventricular drainage: some patients have better left ventricular drainage, a suture in the left ventricle near apical avascular region, a hemostat, a small incision in the center of the sacral suture, and a small incision The left ventricular drainage tube tightens the hemostat and fixes the drainage tube together with the hemostat. Connect the drainage tube to the artificial heart-lung machine system. Check all the pipes and their connections without error. It is sure that there is no obstacle in each channel, and the extracorporeal circulation can be started. After several minutes of parallel circulation, the upper and lower vena cava are blocked and enter the complete extracorporeal circulation. At this time, the upper and lower vena cava blood It is completely intubated into the artificial heart-lung machine and does not flow into the right atrium. At the same time, the blood is cooled. (6) Blocking the ascending aorta: When the whole body temperature drops to about 30 °C, lift the ascending aorta and use the aortic occlusion forceps to block the ascending aorta. Immediately, 4°C cold heart cardioplegia (1015ml/kg) was injected from the perfusion tube of the aortic root, and the surface of the heart was cooled with 4°C iced saline or ice particles to make the heart stop quickly. The operational indicators of cardiopulmonary bypass are as follows: Mean arterial pressure: 5.33 ~ 9.33 kPa (60 ~ 90 mmhg). Central venous pressure: 0.59 ~ 1.18kpa (6 ~ 12cmh2). Body temperature: general surgery about 28 ° C; complex heart surgery can be used at a low temperature of 20 ° C ~ 25 ° C. The myocardial temperature is maintained at 15 ° C to 20 ° C. Flow rate: 50 ~ 60ml / kg for medium flow; 70 ~ 80ml / kg for high flow, clinically used high flow. Children and infants should have a higher flow rate than adults. The dilution cell volume is generally about 25% to 30%. Blood gas analysis: pao2: 13.3 ~ 26.6kpa (100 ~ 200mmhg). Pvo2: 3.3 to 5.3 kPa (25 to 40 mmhg). Ph: 7.35 to 7.45. Paco2: 4.6 ~ 6.0kpa (35 ~ 45mmhg). Urine volume: 2 ~ 10ml / kg / hour. Blood potassium: During the extracorporeal circulation, k+ is maintained at 4-6 mmol/l, and potassium chloride should be given 1 to 2 mmol/kg per hour. Heparinization: human body according to 3mg/kg; pre-filled liquid 1mg/100ml; after 1 hour of operation, heparin was supplemented by artificial heart-lung machine. The act should be kept at around 600 seconds during operation. 6. The heart incision 1 room ditch behind the longitudinal incision into the left atrium, if the room ditch is too short, the lower end of the incision can be extended to the lower rear; 2 through the right atrial incision: cut the right atrium 2cm above the atrioventricular groove, along the atrioventricular The ditch extends downwards. After entering the right atrium, cut the fossa ovalis longitudinally, and expand up and down. When extending downward, it should be biased to the direction of the lower cavity; extend upward to avoid inward deviation, so as not to accidentally injure the aortic sinus. 7. Cleavage: The mitral valve is exposed with a hook, and after the indication for changing the valve is determined, the large flap is sutured as a traction line with a thick thread, and the traction line is clamped with a right angle to expand the large flap. Make a small incision in the large valve about 3mm from the annulus, then use the scissors to cut the large valve forward and backward along the annulus 3mm away from the annulus, and cut the papillary muscle at the tip of the papillary muscle, but do not cut it off. Many, so as not to damage the left ventricular wall. After the junction before and after the arrival, continue to cut the small flap in the same way, try to save the third row of chordae of the small flap, or remove the small flap. Finally, the annulus is used to measure the size of the annulus to determine the desired artificial heart valve number. 8. Stitching: 2-0 with support pad double-needle nylon thread for intermittent suture stitching, needle from the side of the annulus, needle from the side of the chamber, and immediately suture the artificial heart valve from the lateral side of the chamber to the side of the room Stitching ring. The distribution of the suture on the annulus and on the suture ring of the artificial valve should be averaged, and the needle spacing should be adapted to each other. The position of the suture from the suture circle should be as close as possible to the edge. The distance between the sutures is 1 to 2 mm; continuous suture can also be used, but it must be revealed without difficulty. You can use a line of the first needle with a support pad for suture stitching, and then continuous suture to progress on both sides, and finally join the knot; you can also use several sutures for continuous suture, all continuous sutures must pay attention to each needle The suture is tightened to avoid leakage around the valve. 9. Implantation: After all the sutures (finger suture method) are straightened, the artificial flaps are sent into the annulus to confirm that the bed is in place, one by one, the nylon thread is to be hit with 5 knots, and when the thread is trimmed It should not be left too long, and when knotting, pay attention to the knot on the outer side of the seam (ie near the edge), so as to prevent the thread from falling to the center and hinder the function of the artificial flap. 10. Check the artificial flap closure and opening function. 11. Flush: Rinse the heart chamber thoroughly with cold saline. 12. Suture the incision: suture the left atrial incision, or suture the interatrial incision to suture the right atrial incision. All heart incisions are two consecutive sutures. When suturing, the suture must be tightened to prevent blood leakage. 13. Exhaust: Before suturing the left atrial incision, the left atrium and left ventricle should be filled with normal saline to drive out the gas; if the right atrium is used, the left atrium and left ventricle should be filled with normal saline at the interval of the interspersed room. When the right atrial incision is made, the right atrium and the right ventricle are filled with saline. After the heart incision is sutured, the left ventricle and the ascending aorta root are vented. The aortic root venting can be performed by the pinhole of the cardiac arrest fluid, which can be connected to the left heart drainage tube for exhausting or open. Exhaust, the left chamber is vented with a slotted needle. 14. Open ascending aortic occlusion forceps: The ascending aortic occlusion forceps should be opened as soon as possible (if the occlusion time is longer, in order to reduce the time to block the ascending aorta, the right atrium can be closed after the interatrial incision is sewed. Open the ascending aortic occlusion forceps first, then the heart can often automatically re-jump, if you can not automatically re-jump, the myocardium has a certain tension or ventricular fibrillation, you can shock defibrillation. complication 1, fully evaluate the patient's cardiopulmonary function, preoperative examination should be conducted breath test. The normal value is 20 to 35 seconds. The breath holding time is shortened, indicating that the breathing function is incomplete. Preoperative exercise breathing function (blowing balloon) and cough exercise. 2, patients with pulmonary insufficiency and patients with a history of smoking, preoperative and aerosol inhalation support treatment.

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