Open heart surgery

Arrhythmias. The first solution to cardiovascular problems arising from arrhythmias came about as a result of a complication caused by open-heart surgery. During procedures to correct congenital defects in children s hearts, the electrical conduction system often became impaired, and until it healed, the heart could not contract sufficiently without outside electrical stimulation. A system that plugged into a wall outlet was considered adequate until an electrical storm knocked out power, lea ding to the development of the first battery-powered external pacemaker. 

Valve Problems. The primary solution to valve problems has been implantable replacement valves. The introduction of these devices necessitates open-heart surgery. There are two types of valves available tissue (porcine and bovine) and mechanical. The disadvantage of tissue valves is that these have a limited life of about seven years before they calcify, stiffen, and have to be replaced. The mechanical valves can last a lifetime, but require anticoagulant therapy. In some patients, anticoagulants may not be feasible or may be contraindicated. Of the valves which require replacement, 99% are mitral and aortic valves. The valves on the left side of the heart are under much greater pressure because the left ventricle is pumping blood out to the entire body, instead of only to the lungs. Occasionally, two valves are replaced in the same procedure. 

Efforts to develop an artificial heart have resulted in a number of advancements in the assist area. The centrifugal pump for open-heart surgery, the product of such an effort, has frequently been used to support patients after heart surgery (post-cardiotomy), or as a bridge to life prior to transplant. 

Devices for the 1990s. The 1990s may turn out to be the decade of active arrhythmia-control devices. Implantable devices to pace, cardiovert, and defibrillate the heart without the need for open-heart surgery should become widely accepted before the year 2000. Dramatic developments and... 

Implantable valves, particularly mechanical valves which continue to encroach on tissue valves, are unique. Methods such as valvuloplasty, mitral valve repair, or use of ultrasound are unlikely to reduce the number of valve replacements into the twenty-first century. Valve selection remains in the hands of the surgeon because of the critical nature of the procedure. If anything goes wrong, the result can be catastrophic to the patient. Cost of a valve, from 3000— 4000, is a relatively small part of the cost of open-heart surgery which can mn as high as 30,000. Growth of the cardiovascular valve market has slowed in the United States with the decline of the threat of rheumatic fever. 

Ca.rdia.c-AssistDevices. The principal cardiac-assist device, the intra-aortic balloon pump (lABP), is used primarily to support patients before or after open-heart surgery, or patients who go into cardiogenic shock. As of the mid-1990s, the lABP was being used more often to stabilize heart attack victims, especially in community hospitals which do not provide open-heart surgery. The procedure consists of a balloon catheter inserted into the aorta which expands and contracts to assist blood flow into the circulatory system and to reduce the heart s workload by about 20%. The disposable balloon is powered by an external pump console. 

S100B Sensitive marker of hypoxic brain damage in infants and children undergoing open-heart surgery... 

Cardioplegia Arrest heart for open heart surgery repair of damaged vessels... 

PHB has been claimed to have piezo-electric properties similar to those of natural bone, giving it potential as biodegradable fixative plates that could actually stimulate bone formation and consequently promote the healing of the patient [117]. Furthermore, PHB has been used to produce non-woven patches for pericardium repair following open-heart surgery. 

J.H. Yun, L. Lee, J.A. Wahr, V.C. Yang, and M.E. Meyerhoff, Clinical application of disposable heparin sensors. Blood heparin measurements during open heart surgery. ASAIO J. 41, M661-M664 (1995). 

S. Watarida, S. Shiraishi, T. Sugita, K. Katsuyama, Y. Nakajima, R. Yamamoto, Y. Yamamoto, M. Imura, R. Hirokawa, A. Mori, Effects of Docarpamine on Hemodynamics after Open Heart Surgery in Children , Awn. Thorac. Cardiovasc. Surg. 2000, 6, 106-109. 

Analysers for clinical purposes have been designed [129-131] and even a bedside analyser for monitoring Na, K, Cs and jJ-D-glucose in patients blood [127] or a blood potassium analyser for use during open-heart surgery [109]. A computer-controlled interference correction has been proposed [44], in which the standards are mixed to match the electrode potential obtained in the test solution. A simple caUbration in flow systems [61] involves dilution of the standard solution and monitoring of the ISE potential as a function of the diluent volume and dilution time. 

Cardiac resuscitation After open heart surgery, when epinephrine fails to improve... 

Surgery of the heart and blood vessels Give an initial dose of not less than 150 units/kg to patients undergoing total body perfusion for open heart surgery. Often, 300 units/kg is used for procedures less than 60 minutes and 400 units/kg is used for procedures more than 60 minutes. 

Hypotension postbypass - Rare occasions of hypotension upon discontinuation of cardiopulmonary bypass during open-heart surgery in patients receiving amiodarone have been reported. 

IV Relief of severe pain pain of Ml used preoperatively to sedate the patient and allay apprehension, facilitate anesthesia induction, and reduce anesthetic dosage control postoperative pain relieve anxiety and reduce left ventricular work by reducing preload pressure treatment of dyspnea associated with acute left ventricular failure and pulmonary edema produce anesthesia for open-heart surgery. 

Up to 150 meg/kg may be necessary. It has been used for open heart surgery and other major surgical procedures to protect the myocardium from excess oxygen demand and for complicated neurological and orthopedic procedures. 

For preventative use during open heart surgery, give 1.5 g IV at the induction of anesthesia and every 12 hours thereafter for a total of 6 g. P.886... 

Phenytoin, like lidocaine, is more effective in the treatment of ventricular than supraventricular arrhythmias. It is particularly effective in treating ventricular arrhythmias associated with digitalis toxicity, acute myocardial infarction, open-heart surgery, anesthesia, cardiac catheterization, cardioversion, and angiographic studies. 

Treatment and prevention of acute hypotension shock (associated with cardiac decompensation, Ml, open heart surgery, renal failure, or trauma), treatment of low cardiac output, treatment of CHF IV 1 mcg/kg/min up to 50 mcg/kg/min titrated to desired response. 

It is indicated as a narcotic analgesic supplement in general or regional anaesthesia, as an anaesthetic agent with oxygen and skeletal relaxant in selected high risk patients (e.g. open heart surgery). 

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