an auxiliary flow; a shunt; a surgically created pathway circumventing the normal anatomical pathway, such as in an artery or the intestine.
Bypass. Single artery bypass of an occluded right coronary artery. From Dorland's, 2000.
aortofemoral bypass insertion of a vascular prosthesis from the aorta to the femoral artery to bypass atherosclerotic occlusions in the aorta and the iliac artery.
aortoiliac bypass insertion of a vascular prosthesis from the abdominal aorta to the femoral artery to bypass intervening atherosclerotic segments.
axillofemoral bypass insertion of a vascular prosthesis or section of saphenous vein from the axillary artery to the ipsilateral femoral artery to relieve lower limb ischemia in patients in whom normal anatomic placement of a graft is contraindicated, as by abdominal infection or aortic aneurysm.
axillopopliteal bypass insertion of a vascular prosthesis from the axillary artery to the popliteal artery to relieve lower limb ischemia in patients in whom the femoral artery is unsuitable for axillofemoral bypass.
diversion of the flow of blood from the entrance to the right atrium directly to the aorta, usually via a pump oxygenator
, avoiding both the heart and the lungs; a form of extracorporeal circulation
used in heart
(coronary artery bypass
) a section of saphenous vein or other conduit grafted between the aorta and a coronary artery distal to an obstructive lesion in the latter; called also aortocoronary bypass
extra-anatomic bypass an arterial bypass that does not follow the normal anatomic pathway, such as an axillofemoral bypass.
extracranial/intracranial bypass anastomosis of the superficial temporal artery to the middle cerebral artery to preserve function or prevent stroke or death in patients with stenosis of the internal carotid or middle cerebral artery.
femorofemoral bypass insertion of a vascular prosthesis between the femoral arteries to bypass an occluded or injured iliac artery.
femoropopliteal bypass insertion of a vascular prosthesis from the femoral to the popliteal artery to bypass occluded segments.
hepatorenal bypass insertion of a vascular prosthesis between the common hepatic artery and the renal artery, serving as a passage around an occluded segment of renal artery.
left heart bypass diversion of the flow of blood from the pulmonary veins directly to the aorta, avoiding the left atrium and the left ventricle.
partial bypass the deviation of only a portion of the blood flowing through an artery.
partial ileal bypass anastomosis of the proximal end of the transected ileum to the cecum, the bypass of the portion of the small intestine resulting in decreased intestinal absorption of and increased fecal excretion of cholesterol; sometimes used in treatment of hyperlipidemia.
right heart bypass diversion of the flow of blood from the entrance of the right atrium directly to the pulmonary arteries, avoiding the right atrium and right ventricles.
A means of circumvention; a shunt. It is used surgically to install an alternative route for the blood to flow past an obstruction if a main or vital artery, e.g., the abdominal aorta or a coronary artery, becomes obstructed. The various procedures are named according to the arteries involved, e.g., coronary artery, aortoiliac, or femoropopliteal bypasses. The circulation of the heart may be bypassed by providing an extracorporeal device to pump blood while a surgical procedure is being done on the coronary arteries or cardiac valves.
aortocoronary bypassCoronary artery bypass.
CORONARY ARTERY BYPASS: Myocardial reperfusion by coronary artery bypass graft surgery
coronary artery bypass
Surgical establishment of a shunt that permits blood to travel from the aorta or internal mammary artery to a branch of the coronary artery at a point past an obstruction. It is used to treat coronary artery disease.
Traditional surgery requires opening the chest and sternum, spreading the ribs, and use of external heart/lung oxygenation. Less invasive techniques use several small incisions (keyhole surgery), smaller surgical instruments, and fiber-optic cameras. Recovery time is reduced and there are fewer postoperative complications. See: illustration
Preoperative: The surgical procedure and the equipment and procedures used in the postanesthesia and intensive care units are explained. If possible, a tour of the facilities is arranged for the patient. The nurse assists with insertion of arterial and central lines and initiates cardiac monitoring when the patient enters the operating room.
Postoperative: Initially the postoperative patient will be intubated, mechanically ventilated, and will undergo cardiac monitoring. He will also have a nasogastric tube, a chest tube and drainage system, an indwelling urinary catheter, arterial and venous lines, epicardial pacing wires, and, often, a pulmonary artery catheter.
Signs of hemodynamic compromise, e.g., severe hypotension, decreased cardiac output, and shock, are monitored; vital signs are obtained and documented according to protocol until the patient's condition stabilizes. Disturbances in heart rate or rhythm are monitored; any abnormalities are documented and reported. Preparations are made to initiate or assist with epicardial pacing, cardioversion, or defibrillation as necessary. Pulmonary artery, central venous, and left atrial pressures are monitored, and arterial pressure is maintained within prescribed guidelines (usually between 110 and 70 mm Hg). Peripheral pulses, capillary refill time, and skin temperature and color are assessed frequently; the chest is auscultated for changes in heart sounds or pulmonary congestion. Any abnormalities are documented and reported to the surgeon. Tissue oxygenation is monitored by assessing breath sounds, chest excursion, symmetry of chest expansion, pulse oximeter, and arterial blood gas (ABG) values. Ventilator settings are adjusted as needed. Fluid intake and output and electrolyte levels are assessed for imbalances. Chest tube drainage is maintained at the prescribed negative pressure (usually -10 to -40 cm H2O); chest tubes are inspected for patency. The patient is assessed for hemorrhage, excessive drainage (> 200 ml/hr), and sudden decrease or cessation of drainage. Prescribed analgesics and other medications are administered.
Throughout recovery the patient is evaluated for changes in oxygenation, ventilation, neurological status, and urinary output. After the patient is weaned from the ventilator and extubated, chest physiotherapy and incentive spirometry are used, and the patient is encouraged to breathe deeply and to cough to prevent atelectasis of the lung and to clear mucus from the airway. The patient is helped to change position frequently. Help is also given with range-of-motion exercises and with active leg movement and gluteal and quadriceps setting exercises.
Before discharge the patient is instructed to report any signs of infection (fever, sore throat, redness, swelling, or drainage from the leg or chest incisions) or cardiac complications (angina, dizziness, rapid or irregular pulse, or increasing fatigue or prolonged recovery time after activity or exercise). Postpericardiotomy syndrome often develops after open heart surgery. Postoperative depression may also develop weeks after discharge; both patient and family are reassured that this is normal and usually passes quickly. The patient is advised to observe any tobacco, sodium, cholesterol, fat, and calorie restrictions, which may help reduce the risk of recurrent arterial occlusion. The patient needs to maintain a balance between activity and rest and should schedule a short afternoon rest period and plan to get 8 hr of sleep nightly. Frequent rest should also follow any tiring activity. Participation in the prescribed cardiac rehabilitative exercise program is recommended, and any activity restrictions (avoiding lifting heavy objects, driving a car, or doing strenuous work until specific permission is granted) are reinforced. Appropriate reassurance is offered that the patient can climb stairs, engage in sexual activity, take baths or showers, and do light chores. The patient is referred to local information and support groups or organizations, such as the American Heart Association. Synonym: aortocoronary bypass
extra-anatomic vascular bypass
Surgical revascularization for peripheral vascular disease of the limbs, using a prosthetic graft (e.g., axillofemorally or femorofemorally) to divert blood to a site distal to an arterial obstruction.
Postoperatively, it is important to monitor the patient's vital signs for changes, esp. of pulse and rhythm, and to assess the patient for symptoms of angina pectoris or arrhythmias. Cardiac monitoring and frequent ECGs are routine aspects of care. The surgical wound is checked for bleeding or hematoma formation, or signs of infection or dehiscence. Peripheral pulses are palpated using a doppler, if necessary, to determine peripheral perfusion.
Any surgical procedure in which the stomach, or most of the stomach, is isolated and disconnected from the rest of the upper gastrointestinal tract. See: Roux-en-y gastric bypass
A surgical procedure for decreasing absorption of nutrients from the small intestine by anastomosing the proximal jejunum to the distal ileum. Although it can be used to treat obesity, jejunoileal bypass has been replaced by gastric bypass procedures because of the significant complications of jejunoileal bypass surgery.
minimally invasive direct coronary artery bypass Abbreviation: MIDCAB
The placement of a coronary artery graft without stopping the heart or using a cardiopulmonary bypass (heart-lung machine). A thoracotomy rather than a medial sternotomy is used to access the heart, which is then stabilized by use of a compression or suction device to decrease movement. The procedure is used primarily for grafting a single vessel, usually the left or right internal mammary artery. Although MIDCAB has the advantages of lower surgical costs and possibly a decreased risk of complications, it has the disadvantages of limited surgical visibility and more difficult suturing. Synonym: off-pump coronary artery bypass
off-pump coronary artery bypass Minimally invasive direct coronary artery bypass
Roux-en-y gastric bypass
A bariatric surgical procedure in which the superior portion of the stomach is isolated from the rest of the stomach and the jejunum is connected to it. As a result, food passes directly from the proximal stomach into the middle of the small intestine. It bypasses the majority of the stomach, which is isolated from the working portion of the stomach and from the duodenum. An opening is made in the duodenum and the jejunum, and the two organs are connected via a surgical stoma. This permits drainage into the jejunum of gastric secretions from the isolated greater curvature of the stomach. This form of gastric bypass is the most common bariatric surgical procedure and among the most successful. Since the duodenum absorbs many important vitamins and nutrients, including iron, vitamin B12, and calcium, nutritional deficiencies and iron-deficiency anemia are common complications. Others include nausea, vomiting, ulcers, and anastomotic leaks. illustrationillustration