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(1) RN, Anaesthetics / Operating Theatres, St. Vincent's Hospital
(2) RN, Operating Theatres, St Vincent's Private Hospital
[Abstract] [Introduction] [Background] [The Technology] [Procedure] [Nursing Care] [Benefits for Patients] [Considerations] [Potential complications] [Considerations for implementation] [Future implications] [References]
Major heart surgery without the need for a sternotomy? Heartport is providing a revolutionary technology that enables the surgeon to perform a wide variety of cardiac surgery via small incisions using minimally invasive techniques. This surgery, recently introduced to Australia, uses minimally invasive techniques for coronary bypass grafting and mitral valve replacement These are some of the surgeries successfully performed at St Vincent's Hospital, Sydney.
By eliminating the need for a painful sternotomy the greatest benefit for the patent is to recover and resume 'normal' activities much quicker than those patients following conventional cardiac surgery. Hereby allowing for shorter hospital stays. Other advantages in recovery will also be discussed.
The system of catheters and cannulae and their function, provided by Heartport will be explored, as an understanding of the new technology is important to all those involved ranging from the ward nurse to the cardiac specialist.
Perioperative nursing roles are extended and nursing care postoperative is positively effected as recovery period and hospital stays are reduced. Other considerations regarding nursing care for the patient undergoing minimally invasive cardiac surgery will be explored.
Recently performed in Australia, Heartport has already shown some of the benefits mentioned and hopefully will become an alternative technique to conventional cardiac surgery as laparascopic techniques are to gall bladder surgery.
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Recent developments in cardiac surgery are utilising minimally invasive approaches which eliminate the need for sternotomy. Two techniques have emerged. In one, known as "MIDCAB" (or minimally invasive direct coronary artery bypass), grafting is performed on the beating heart. The second technique, known as "Port Access" utilises peripheral cardiopulmonary bypass to operate on the still heart via small incisions or ports between the ribs. This paper discusses the "Port Access" technique which has recently been introduced at St Vincent's Hospital.
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Coronary artery disease (CAD) is the leading cause of death in Australia accounting for 24% of all deaths in 1995. This is an alarming figure when compared to Motor Vehicle Accidents which accounted for 1.6% of all deaths in the same year (Heart Foundation of Australia, 1996).
CAD affects the arteries of the heart and leads to a reduced flow of blood, oxygen and nutrients to the myocardium. CAD is ' associated with angina, myocardial infarction, chronic disability and death. Treatment focuses on preventing the progression of the disease, reducing heart muscle requirements, and increasing coronary artery blood flow (McCance & Heuther, 1994).
Proficiency in the use of percutaneous transluminal coronary angioplasty, atherectomy, intra-coronary stents, and laser balloon angioplasty have expanded the options for many patients with CAD. However, invasive surgical intervention remains at the forefront of treatment.
The first coronary artery bypass grafting surgery (CABG) was performed by Favaloro at the Cleveland Clinic in 1968 and in Australia by Windsor and Shanahan at St Vincent's Hospital in 1969 (Shanahan, 1984). Since then cardiac surgery has witnessed the widespread performance of safe and effective operations to correct even complex heart disease. Over the last three decades, advances in operative technique, myocardial protection, and technology have improved results in cardiac surgery.
CABG surgery involves the surgeon bypassing the blocked artery by connecting a conduit graft to the aorta and anastomosing it beyond the blockage. Blood will then flow from the aorta, through the bypass graft and into the coronary artery beyond the area of disease. The type of graft used has no effect on the early postoperative outcome, however, long term patency rates and patient's survival rates are higher with Internal, Mammary Artery grafts as opposed to Saphenous Vein and Radial Artery grafts (Glanze, 1990).
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Conventional heart surgery requires a sternotomy to enable the surgeon to stop and protect the heart and place the patient on Cardiopulmonary Bypass (CPB) before proceeding with grafting. While extremely effective in treating CAD, the trauma caused due to the sternotomy is associated with pain, an increased risk of infection, extended hospitalisation and a long recovery period (Peters et al, 1996).
Recent developments in CABG surgery explores the Minimally Invasive (MI) approach, similar to that utilised in laparoscopic procedures. The development of W CABG has followed two distinct paths. The first is performing grafts on the beating heart (known as MIDCAB or minimally invasive direct coronary artery bypass) and the second with peripheral CPB and cardioplegia known as "Port Access". Both avoid a sternotomy, with the port access system being favoured due to the improved anastomoses (Mundy, 1997).
The first port access CABG procedure was performed at Stanford University, California in April 1995 (Heartport August 24,1995), since then it has become an established alternative form of heart surgery. While still in the early stages of development in Australia, it offers potential for shorter hospitalisation time, less pain, quicker rehabilitation, less cost, a reduction in wound infection and a better cosmetic effect These advantages have been documented in medical literature (Schwartz et al, 1997 and Frann et al, 1997).
The Heartport Port Access system is a revolutionary technology for performing major heart surgeries with minimally invasive techniques. The Heartport Port Access system is an integrated system of catheters and cannulae that enable the surgeon to perform a wide variety of cardiac surgeries via small incisions between the patient's ribs eliminating the need for a sternotomy.
Minimally invasive cardiac surgery (MICS) procedures include single vessel CABG's, multiple vessel CABG's mitral valve repair (MVR) and aortic valve repair (AVR). The Heartport system allows enough access and manoeuvrability to harvest ideal replacement arteries while the heart is arrested and protected, using the endopulmonary bypass system (Heartport manual, 1997).
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The endopulmonary bypass system is a catheter based system of devices that permits the heart to be arrested and maintain bypass. The system also includes specially designed long fine instruments enabling access to the surgical field.
The system includes three catheters and two cannulae: endocoronary sinus catheter, endopulmonary vent catheter; endoarterial return cannula; the endoaortic clamp catheter and endovenous drainage cannula.
The endocoronary sinus catheter is inserted into the internal jugular or subclavian vein. This occludes the coronary sinus, monitoring coronary sinus pressure and central venous pressure (CVP) and delivers cardioplegia into the coronary sinus via a retrograde manner. The endopulmonary vent catheter is inserted via a neck vein into the pulmonary artery. This serves to remove blood from the pulmonary artery decompressing the heart. The endoarterial return cannula is inserted into the femoral artery. One arm returns oxygenated blood to the body and the other allows the passage of the endoaortic clamp catheter, allowing a single femoral incision. The endoaortic clamp catheter is used to occlude the ascending aorta. Similar to the cross-clamp used in open heart surgery, the catheter occludes the aorta with the inflation of its balloon, and is also used to deliver antegrade cardioplegia to the coronary arteries. It is also used as a vent for the aortic root and monitors pressures. The endovenous drainage catheter is inserted into the femoral vein, and is placed at the junction of the right atrium and superior vena cava. This allows venous drainage of blood from the right side of the heart ( Heartport manual, 1997).
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The Heartport Port Access system procedure involves many of the steps used for conventional heart surgery, but significantly, eliminates the need for a 30-38cm sternotomy. The patient is prepared in the same way as for conventional surgery with the exception that a double lumen endotracheal tube is used for intubation. This is to allow maintenance of ventilation in the right lung whilst the left lung is deflated to enable better visibility of the left internal mammary artery (LIMA).
CPB is achieved via the integrated system of catheters and cannulae that are inserted into the groin and neck and advanced until they reach the heart. The advancement and positioning of the catheters in the heart are monitored using fluoroscopy and transoesophageal echocardiography. This monitoring is essential throughout the entire case for both correct placement of all lines and maintenance of their position (Seigel et al, 1997). There is a potential for the endoaortic clamp to slip and occlude the arteries leading off the aortic arch, blocking blood flow to the rest of the body including the brain, causing right sided damage if not detected. This would be indicated by a, sudden drop in pressure. If a transcranial doppler is not used in assessing migration of the endoaortic clamp then' bilateral radial artery monitoring is used for the assessment. Close monitoring of ECG and aortic root pressures and myocardial temperature are maintained, throughout the procedure.
Surgeons operate through small ports between the ribs. If needed a small piece of rib or cartilage is removed to provide an optimal viewing field. Direct visualisation enables surgeons to operate on all areas of the heart. The small ports and incisions are different for various procedures.
At the end of the surgery the patient is re-warmed, bypass is weaned and pleural and pericardial drains are insertedThe aforementioned catheters and cannulae are removed. The patient is extubated and re-intubated with a single lumen tube, with the future potential of being extubated on the table.
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The nursing role for perioperative nurses is extended. Anaesthetic and scrub nurses prepare the catheters. A sterile technique is required for the preparation of the catheters, and the anaesthetic nurse is now required to scrub and assist the anaethetist in the insertion of the lines. The patient is prepared for theatres in the same way as for conventional surgery. Bilateral arterial lines are inserted if the radial artery is not required for grafting. The patient is kept warm whilst in the anaesthetic bay.
The immediate post-operative care of patients undergoing minimally invasive bypass grafting is, similar to the routine care provided for patients undergoing standard cardiopulmonary bypass surgery. Patients are presented to ITU with pleural. and pericardial drains in situ and are intubated. Currently patients are extubated within 4 hours of arriving in ITU. The patient requires intensive nursing during recovery as there is a potential for a decrease in oxygenation , status, haemodynamic instability, ECG changes and altered haemostatis ( Mizell et al, 1997).
Patients are monitored after general anaesthesia for the adequacy of oxygenation and the effectiveness of ventilation. Arterial blood gas analysis is routinely obtained 30 minutes after extubation and again the next morning. Pulse oximetry readings are monitored continually. After extubation a supplemental supply of oxygen therapy is used according to patients needs.
Ausultations of the lung are assessed every 1-2 hours for adequacy of lung sounds. Aggressive pulmonary toilets such as coughing and incentive spirometry are attended to mobilise secretions and thus reduce the potential for airway obstruction and atelectasis. Chest physiotherapy, low levels of analgesia and sedation, and progressive mobilisation are encouraged to prevent pulmonary deterioration. Once transferred to the ward patients can aim to progress to full mobilisation after two days and are discharged approximately 4 days post operatively if no complications are experienced ( Glennon et al, 1996).
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The port access system provides comparable safety and efficiency as well as reduced trauma, improved cosmetic effect due to a smaller scar from smaller incisions, shorter hospital stays and improved recovery times (Reichenspurner et al, 1997). According to studies (Vaca et al, 1997) patients experience less pain and return to normal activities faster. Hospital stays are shortened to 4-5 days or fewer, compared to 8-12 days for conventional heart surgery. The recovery period is reduced to 2-4 weeks instead of 8-12 weeks. Overall this leads to lower health care costs. Other patient benefits include the decrease in the incidence of atrial fibrillation (10-15% compared to 35-50% post conventional) therefore lowering morbidity.
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Although less invasive, this is still major heart surgery with the potential for risks and complications, including stroke and death. The success of any surgery is reliant on optimal surgical conditions. With minimally invasive procedures, there is a potential for excessive blood to obscure the operative field. If this occurs then the surgical team may need to ' revert to the conventional sternotomy approach. A patient's particular anatomy or clinical circumstance may cause the surgeon to switch to a sternotomy to complete the operation safely and effectively.
At this early stage not all patients are suitable for the minimally invasive approach. Currently it is restricted to patients who have stenosis in the left anterior descending (LAD) branch of the coronary artery. However it is expected that with experience the number of grafts able to be performed will increase. This has already been demonstrated by a surgeon in America who recently successfully achieved six grafts (Heartport, July 9,1997).
Risks and complications of any type of heart surgery include damage to major blood vessels or hew structures, chest wound pain or infection, bleeding from the wound or internal organs, irregular heartbeat, stroke and death. Risks associated with MICS include damage to major blood vessels, especially aortic dissection, and potential damage to ribs.
Experiences at St Vincent's so far have encountered minimal complications. However in those patients who needed to return to theatres due to bleeding the surgeons have been able to approach the problem through the same intercostal incision without the need for a sternotomy.
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Considerations for implementation:
Costs can be phenomenal as instruments are disposable, with new instruments being required for each operation. The initial cost of setting up a theatre with the correct equipment must also be considered. At St. Vincent's the operating table has had to be changed and new equipment purchased which is now a part of the cardiac theatre equipment. The purchase of a transoesophageal echo (TOE), image intensifier (H), used for fluoroscopy, and transcranial doppler have added to the costs. There is also the cost of the actual operation including the cost of the extra staff needed to operate the technology.
Consideration of surgery time is also required. The first procedure at St. Vincent's took approximately 8 hours to complete due to reorganisation of the theatre and learning curve of all involved. It is expected a surgical time of 4 hours, similar to conventional methods, will be achievable as surgeons and other team members become more experienced and confident in the technique.
Whilst the set-up costs have been high and the operational costs have increased in the long term it is anticipated that overall health cost will be lower due to the reduced hospitalisation and improved recovery time.
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The first world congress on MICS in Paris 1997, demonstrated that MICS is becoming an accepted and established alternative to conventional surgery. Recently introduced to Australia, St. Vincent's is keeping abreast with the latest advances in techniques and technologies thus providing patients with a choice in treatment. CABG's and MVR are some of the successful surgeries performed at St. Vincent's Hospital Sydney using the minimally invasive techniques.
Heartport's technology has the potential to change cardiac surgery in much the same way that laprascopic techniques have revolutionised gall bladder surgery. The concept of NfiCS will strongly influence surgery over the next decade.
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Fann, J. 1, Pompili i, M. F., Stevens J. H., Siegel, L. C., St Goar, F. G., Burdon T. A. & Reita, B. A. (1997) Port-Access Cardiac Operations with Cardloplegic Arrest, Annals of Thoracic Surgery, 63:535-9.
Glanze, ? (1990) Mosby's Medical, Nursing and Allied Health Dictionary (3rd edition). The CV Mosby Company: St. Louis. PP: 308-309.
Glennon, S. & Metcalfe, H. (1996) Minimally Invasive Cardiac Surgery, Nursing Standard, 11 (5):54.
Heart Foundation of Australia: NSW Division. (1996).
Heartport Port Access. Minimally Invasive Cardiac Surgery Training Manual (1997) Revised edition. Heartport Inc:USA.
Heartport's Port Access Systems used in six vessel Coronary Bypass
Operation, July 9, 1997. http://www.heartport.com/webpage_templates/press_release.php3?1997-07-09
{Web editor's note: note that this address is different
to the one in the origianal paper-based monographs. The address given
there is out of date, and the one above is correct. Note, also, that there
is much more information now available on this topic at http://www.heartport.com}
McCance, K. L. & Heuther, S. E. (1994) Pathophysiology. The biological basis for disease in adults and children. (2nd edition). Mosby: St Louis. pp: 1018-1022.
Mizell, J. L., Maglish, B. L. & Matheny R. G. (1997) Minimally invasive Direct Coronary Artery Bypass Graft Surgery. Introduction for Critical Care Nurses, Critical Care Nurse. 17(3):4657.
Mundy, J. Cardiothoracic Surgeon, St Vincents Hospital Sydney Ltd. Interview, October, 1997.
Peters, W. S., Smith, J. A. & Resenfeldt, F. L., (1996) A Current Review of Minimally Invasive Cardiac Surgery, Asia Pacific Heart Journal. 5(2):95 -102.
Reichenspurner, H-, Gulielmos, V., Dardel, W. G., & Schuler, S. (1997) Minimally Invasive Coronary Artery Bypass Surgery, New England Journal of Medicine. 336(l):67-68.
Shanahan, M. X, (1984) Coronary Artery Surgery in Australia, Medical Journal of Australia. Feburary 4,pp.128-130.
Schwartz, D. S., Ribakove, G. H., Grossi, F- A., Buttenhem, P. M., Schwartz J. D., Applebaum, R. M., Kronzon, 1, Baurnan F. G., Colvin, S. B. & Galloway, A. C. (1997) Minimally Invasive Mitral Valve Replacement Port-Access Technique, Feasibility And Myocardial Functional Preservation, The Journal Of Thoracic And Cardiovascular Surgery. 113(6):1022-1031.
Seigal, L C., St Goar, F. G., Stevens, J. H., Pompili, M. F., Burdon, T. A., Reitz, B. A. & Peters, W. S. (1997) Monitoring Considerations For Port-Access Cardiac Surgery, Circulation 96(2): 562-567.
Vaca, K. J. Daaki, C. 1, Lambrechts, D. S. (1997) Nursing Care patients undergoing thoroscopic minimally invasive bypass grafting, American Journal of Critical Care, 6(4):281-286.
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