By D. Altus. California State University, Dominguez Hills.
The Freestyle bioprosthesis can usually be oriented in its anatomic position without tension on the coronary button anastomoses purchase genuine tadapox online. In fact tadapox 80 mg with amex, the outpouching nature of bioprosthetic coronary stumps reduces the need for extensive mobilization of the coronary artery buttons discount 80 mg tadapox overnight delivery. However, when the native coronary buttons are more than 120 degrees apart as in a congenitally bicuspid valve, the stentless valve should be rotated 120 degrees. For reattachment of the coronary artery buttons, only one of the coronary stumps is removed and a second opening is made in the noncoronary sinus of the bioprosthesis using a 4-mm aortic punch. Aortic Valve-Sparing Root Replacement Patients with aortic root disease, such as those with Marfan syndrome, have progressive dilation of the aortic sinuses and aortic annulus, which can lead to aortic valve insufficiency despite normal aortic valve leaflets. In these patients, it is possible to replace the diseased aortic root and preserve the aortic valve by reimplanting it inside a Dacron tube graft. All three sinuses of Valsalva are excised, leaving approximately 5 mm of arterial wall attached to the aortic annulus. Where the aortic valve is attached to ventricular muscle, the sutures follow the contour of the commissure between the left and right coronary sinuses. On the side of the left ventricular outflow tract where the aortic valve is attached to fibrous tissue, the sutures are placed in a single horizontal plane. Traditionally, a Dacron tube graft with a diameter matching the calculated external diameter of the ventriculoaortic junction is chosen according to the formula: Diameter = (Average leaflet height × 1. However, to simulate the natural mechanics of the sinuses of Valsalva, a graft 4 to 6 mm larger is selected instead. Theoretically, the creation of these pseudosinuses minimizes systolic contact between the valve cusps and the Dacron graft and reduces diastolic closing leaflet stresses, both of which may enhance valve durability. The previously placed horizontal mattress sutures are then passed through the Dacron graft, taking care to match the commissures to the markings on the graft. Because there are more sutures in the fibrous portion of the left ventricular outflow tract in patients with annuloaortic ectasia, they are placed correspondingly closer in the Dacron graft, thereby correcting the dilation. The tube is lowered over the scalloped aortic valve and the sutures are tied on the outside with a narrow strip of felt sandwiched into the suture line. The graft is cut 2 to 3 cm above the commissures, which are suspended to the graft with mattress 4-0 Prolene sutures reinforced with pledgets. The graft is filled with saline solution to confirm the correct orientation of the commissures and the competence of the valve. The valve is reimplanted inside the graft using the 4-0 or 5-0 Prolene sutures in a running manner. The coronary buttons are then reattached to their respective neosinuses on the graft using 5-0 Prolene sutures. The root reconstruction is completed by placing a figure of eight 5-0 Prolene suture to plicate 2 to 3 mm of graft material in each sinus, 1 cm above and between the commissures. Instead, a second, smaller tube graft corresponding to the external diameter of the ventriculoaortic junction according to the preceding formula is anastomosed to the top of the aortic root graft, thereby effectively reducing the neosinotubular junction. The technique involves the use of deep hypothermic arrest and selective antegrade cerebral protection through right axillary artery perfusion. Selective antegrade cerebral perfusion is begun and the flow adjusted to maintain a perfusion pressure of 50 to 60 mm Hg. The limbs of the trifurcation graft are trimmed to appropriate lengths and sutured sequentially to the arch vessels with 5-0 Prolene beginning with the left subclavian artery, then the left carotid artery, and finally the innominate artery. With an intact Circle of Willis, there is usually back bleeding to allow flushing of air and debris through these side branches into the main graft. The main graft is clamped proximal to the side branches to allow antegrade perfusion to the head and upper extremities. An aortotomy is made across the arch, the redundant arch tissue with debris and blood clots is removed, and ascending and descending aortic segments are completely divided. A Hemashield tube graft of appropriate size is introduced into the lumen of the descending aorta. Perfusion to the lower body is gradually instituted while the arch graft is aspirated to evacuate air. At this time, an opening in the arch graft is made and the beveled end of the trifurcation graft is sewn to the arch graft with 5-0 Prolene suture. During this anastomosis, the heart is perfused with warm blood through the retrograde cardioplegia cannula. Elephant-Trunk Technique When the descending aorta is also diseased and requires subsequent excision and replacement, an elephant- trunk technique is used. The double-layer tube graft edge is then sewn to the descending aorta, buttressed with a Teflon felt strip on the outside with a continuous suture of 3-0 Prolene. At the completion of the anastomosis, the longer segment of the graft is pulled out of the lumen of the tube graft, leaving a “trunk” of approximately 3 cm behind within the lumen of the descending aorta. The trunk is anastomosed to another tube graft when excision of the descending thoracic aorta is undertaken weeks to months subsequently. If a neck for the elephant-trunk anastomosis is not present distal to the left subclavian artery, the site of the distal suture line can be as far proximally as the ascending aorta depending on the narrowest part of the aortic arch. In contradistinction to type A aortic dissection, which requires urgent surgical intervention, patients with type B dissection have a relatively good prognosis with medical therapy. However, elective surgical intervention remains the best form of management and provides superior long-term results in patients who are young and free of other concomitant diseases. Therefore, replacement or stenting of the descending thoracic aorta is the treatment of choice in young, otherwise healthy patients with chronic type B dissection and in older patients with expanding descending aortic aneurysms. Nevertheless, patients who continue to have pain despite maximal medical management, have evidence of contained rupture, or have ischemia of a limb or major organ owing to involvement of an arterial branch by the dissection process should undergo urgent surgical intervention. Interventional radiologists have been important participants in the care of patients with aortic dissections. They are often able to reestablish flow to compromised or occluded aortic branches by fenestrating the intimal flap or stenting the true or false lumen. This may allow a patient with a type B dissection to be stabilized and have surgery on an elective basis. More recently, segments of contained rupture in the acutely dissected descending aorta have been stent grafted (see subsequent text). Some patients with type A dissections continue to demonstrate clinically significant obstruction to flow in one or more aortic branches after ascending aortic replacement. Technique for Replacement of the Descending Thoracic Aorta A postero-lateral thoracotomy through the fifth intercostal space provides adequate exposure of the descending thoracic aorta. A plane of dissection is identified, and vascular loops or umbilical tapes are passed around the transverse arch between the left carotid and the left subclavian arteries, the left subclavian artery, and the descending aorta distally. We routinely use partial left-sided heart bypass for nearly all surgeries on the descending thoracic aorta. The femoral artery is cannulated for arterial return, and either the femoral vein, pulmonary artery, or pulmonary vein is selected for venous drainage (see Replacement of the Ascending Aorta section). The distal aorta is clamped a short distance below the proximal clamp, although the distal extent of aortic dissection may have progressed well below the P.
If the coronary sinus has been placed on the left atrial side of the patch buy tadapox with visa, this will result in high coronary venous pressure cheap tadapox master card, which may impair coronary arterial perfusion purchase tadapox overnight. It is sometimes better to overcorrect and produce mild stenosis than to accept even mild mitral valve insufficiency. Incorrect Height of Patches A perfect valvular repair can be distorted, leading to mitral valve incompetence if either the ventricular or atrial septal patch is too tall or too short. One-Patch Technique Before cannulation, a large piece of pericardium is harvested, placed in glutaraldehyde, and rinsed in saline. A 6-0 Prolene suture is placed at the leading edges of the inferior and superior leaflets to determine the point of partition of the common atrioventricular valve into left- and right-sided valves. The distance between the two points on opposite sides of the annulus where the ventricular septal crest meets the atrioventricular groove is measured. If the patch is too wide, the left atrioventricular valve annulus will be increased, and this may lead to mitral regurgitation. If the left atrioventricular valve tissue is believed to be insufficient, then the width of the patch should be less than the measured distance between the two points on the annulus. This will reduce the size of the left atrioventricular valve annulus and help create a competent valve. Leaflet incisions are nearly always required in the superior and inferior leaflets to allow placement of the pericardial patch. The leaflets should be incised in a line parallel with and overlying the ventricular septal crest, with the incision extending to the level of the annulus. Inadequate Left-Sided Valve Tissue the superior and inferior leaflets should be divided somewhat on the right ventricular side to ensure adequate left-sided leaflet tissue for a competent mitral valve. The pericardial patch is attached to the right ventricular aspect of the defect beginning in the midportion with a running 5-0 Prolene suture. The suture line is continued, weaving in and out of the chordal attachments, until the annulus of the atrioventricular valve is reached both superiorly and inferiorly. With the two ends of this running suture tagged, the pericardial patch is held up within the atrium and the leaflets are suspended from the patch at the correct level with the chordal structures under slight tension. The left-(mitral) and right-(tricuspid) sided valve components are reattached to the pericardial patch initially with a running 6-0 Prolene suture that is secured on both ends of the patch by tying it to the previously placed 5-0 Prolene stitch. The leaflet attachment to the pericardium is then reinforced with multiple pericardial pledgeted horizontal mattress sutures of 5-0 or 6-0 Prolene. Traction sutures on the upper edges of the pericardial patch allow the surgeon to deflect the patch back and forth to visualize the left and then the right side of the repair. The cleft between the superior and inferior leaflet components of the left atrioventricular valve is approximated with interrupted sutures as described in the preceding text. The left atrioventricular valve is again tested with saline, and any areas of regurgitation are noted and repaired as discussed in the Two- Patch Technique section. The remainder of the pericardial patch is then secured to the atrial septal defect as described previously. Running suture is completed inferiorly and interrupted reinforcing mattress sutures are placed from the left side through the mitral component, patch, and then tricuspid component and tied on the right side. One-Patch Technique with Direct Ventricular Defect Closure Recently, some surgeons have advocated direct suture closure of the ventricular septal defect in patients with complete atrioventricular septal defects. These sutures are brought up through the superior and inferior bridging leaflets and then through the pericardial patch used to close the atrial defect. When deficient left-sided leaflet tissue is present, the sutures are placed more toward the right side to create a larger mitral valve. The cleft between the left superior and inferior leaflets is closed with interrupted 6-0 or 7-0 Prolene sutures. The mitral valve is tested with saline, and if needed, annuloplasty sutures are placed as described in the preceding text. The pericardial patch is sewn into place with a continuous 6-0 Prolene suture, taking shallow bites between the annulus inferiorly and the coronary sinus to avoid the atrioventricular node. If the ventricular septal defect is too deep, the tension required to pull the leaflets down to the septum may cause the sutures to pull through the muscle or may distort the valve and lead to unacceptable mitral insufficiency. At least theoretically, this direct closure of the ventriculoseptal defect could cause left ventricular outflow tract obstruction. A modification of this technique, closing the superior and/or inferior most extents of the ventricular septal defect directly and patching the other side or midportion of the defect may be useful. If the operation has been performed on cardiopulmonary bypass, rewarming is begun during closure of the atrial septal defect component. After closing the right atrium, the heart is filled, the aortic cross-clamp is removed, and deairing procedures are performed. If the operation has been accomplished under circulatory arrest, the heart is filled with saline after closing the right atriotomy. Cardiopulmonary bypass is recommenced, the aortic cross-clamp is removed while deairing through the ascending aorta, and rewarming is carried out in the usual manner. Most of these patients are not candidates for biventricular repair and should undergo a Norwood-type initial procedure followed by staging to a completion Fontan operation (see Chapters 30 and 31). Patients with unbalanced atrioventricular septal defects to the left may tolerate a biventricular approach by leaving a restrictive atrial septal defect. Alternatively, they may be candidates for a one and one-half ventricle repair combining a septation procedure with a bidirectional cavopulmonary anastomosis (see Chapter 31). Obstruction can occur at a specific site or involve many segments of the right ventricular outflow tract. Obstruction of the right ventricular outflow tract is commonly associated with other cardiac anomalies. An enlarged acute marginal branch of the right coronary artery often overlies the area of obstruction where an area of “dimpling” of the right ventricular free wall is also often present. Most often, a double-chambered right ventricle is associated with a perimembranous type of ventricular septal defect. After identifying the papillary muscles of the tricuspid valve, the remainder of the obstructing muscle is resected until the fibrous “os infundibulum” is visible. Misidentifying the Ventricular Septal Defect the circular opening visualized if a right ventriculotomy approach is used may, on first examination, appear to be the ventricular septal defect. Creating a Right Ventriculotomy In resecting the dense muscle bundles of double chamber right ventricle, it is important not to debride muscle through (and out) the right ventricular free wall. As a general rule, if a right angle clamp can be placed behind the muscle bundle and the bundle divided over the clamp, the surgeon will not “button hole” the right ventricle. These children usually present with mild to moderate cyanosis and may have intermittent hypoxic spells. Echocardiography can demonstrate the presence of additional ventricular septal defects, can usually delineate the initial course of the right and left coronary arteries, and can size the main and proximal right and left pulmonary arteries. Cardiac catheterization is reserved for those patients in whom the echocardiographic diagnosis is incomplete, when aortopulmonary collateral vessels are suspected, or for patients with previous palliative procedures. Staged Approach Several centers have reported satisfactory results with complete repair of tetralogy of Fallot in neonates.
To date discount tadapox 80mg amex, governmental and private sector accrediting bodies have not coordinated their efforts to develop actionable discount 80mg tadapox visa, integrated generic tadapox 80mg online, validated, and reliable systems to measure and report medical errors and patient safety . In some cases, mandated reporting and specific treatment algorithms have been recommended for critical illness like sepsis and ventilator-associated pneumonia. Approaches to safety used by these industries include well-defined strategies to protect workers and customers. Technology-based approaches are part of this strategy, but organizational and psychological factors contribute as well. For example, developing a culture of safety has been identified as one important method of improving safety. Although technical, organizational, and psychological interventions have been effective for other industries, it is also worth noting the limits of these methods. Persistence of fatalities for the aviation and auto transportation industries suggests that safety efforts may be counterbalanced by other competing risk factors such as high volumes, greater complexity of the product, cost pressure, and rapidly changing designs. These risk factors are particularly relevant to healthcare because the patient population is changing (with greater numbers of very old, immunocompromised, and high-risk patients), and technology is evolving at very rapid rates . Thus, there is likely an upper limit in terms of cost-effective healthcare safety that can be reached. Specialized physician training and development of a culture of safety will also be essential in order to achieve such an excellent level of safety in the setting of intensive care. Freedom from accidental or preventable injuries produced by medical care Medical errors: Mistakes made in the process of care that result in or have the potential to result in harm to patients. Mistakes include the failure of a planned action to be completed as intended or the use of a wrong plan to achieve an aim. These can be the result of an action that is taken (error of commission) or an action that is not taken (error of omission) Active errors: Errors that occur at the interface between a human provider and a care delivery system (e. An example of a latent error would be understaffing of nurses in an intensive care unit Serious medical errors: A medical error that causes harm (or injury) or has the potential to cause harm. Does not include trivial errors with little or no potential for harm or nonpreventable adverse events Intercepted serious error: A serious medical error that is caught before reaching the patient Nonintercepted serious error: A serious medical error that is not caught and therefore reaches the patient but because of good fortune or because the patient had sufficient reserves to buffer the error, it did not cause clinically detectable harm Nonpreventable adverse event: Unavoidable injury due to appropriate medical care Preventable adverse event: Injury due to a nonintercepted serious error in medical care Slips: Failures of automatic behaviors or lapses in concentration (e. Within this context of safety, medical errors are defined as “mistakes made in the process of care that result in or have the potential to result in harm to patients. Mistakes include the failure of a planned action to be completed as intended or the use of a wrong plan to achieve an aim. These can be the result of an action that is taken (error of commission) or an action that is not taken (error of omission)” . Latent errors define a less obvious failure of a healthcare organization or structure that have contributed to errors or allowed the errors to harm patients. Other typologies include domains that ascribe characteristics of preventability, seriousness, and whether the error was intercepted before affecting a patient  (Table 134. Mistakes represent incorrect choices, such as choosing the wrong drug for a clinical condition, and typically result from inexperience or lack of knowledge or training. The remedies for these two types of errors differ; slips are more responsive to removing distractions from the workplace or automating monotonous tasks, whereas mistakes respond to increased training or supervision. Incidents are defined as unexpected or unanticipated events or circumstances not consistent with the routine care of a particular patient, which could have or did lead to an unintended or unnecessary harm to a person, or to a complaint, loss, or damage. The Critical Care Safety Study defines adverse events as “Any injury due to medical management, rather than the underlying disease” . As an example, if proper procedures are followed for central line placement but the patient develops a pneumothorax, this would constitute an adverse event. As the safety and quality movement has progressed, it is increasingly difficult to look at one aspect isolated from the other. Although it may be useful for research purposes to identify issues as either safety related or quality related, on a day-to-day basis the distinction between safety and quality issues is increasingly nominal. Structure is defined by the physical environment and plant (buildings, equipment, information technology resources). The most concrete outcome is mortality; the term can also include quality of life measures, specific morbidities, exercise capacity, and others. An additional dimension worth considering is the context in which care is delivered, also called “safety culture. Measurement of this dimension, while difficult, may be worthwhile as there is some evidence that variations in culture are linked to clinical outcomes . First, reports have been generated in a punitive environment that focuses on the provider who committed an error rather than on systems of care, and thus discourages self-reporting of errors . Second, each report of an error represents a “numerator” value that does not give insight into the denominator pool of patients at risk of similar errors. Third, definitions of errors used by incident reporting systems vary, which impedes data synthesis, analysis, collaborative work, and evaluation of the impact of changes in healthcare delivery . And fourth, appropriate functional data spanning the domains of structure, process, and outcome are not collected, which impedes the ability to “deconstruct” an error to understand its root causes and patient impact. Internet-based systems allow anonymous reporting of errors, encouraging providers who have either committed an error or have knowledge of an error to enter related information into a central data repository . Institutional commitment to a “culture of safety” has a motivational effect on error reporting because healthcare providers recognize that “someone is listening. This culture requires several essential process elements to enhance error reporting: A team (a) convenes to develop preventative solutions to a reported error, (b) generates plans to improve the care, and (c) has a method for implementing and measuring the impact of their plan . The taxonomy used was designed to conform to an analytical framework and common word usages to promote its use and the understanding of its output. Data entered allows classification of a patient safety event within five complementary primary groups: impact—the outcome or effects of medical error and systems failure, commonly referred to as harm to the patient; type—the implied or visible processes that were faulty or failed; domain—the characteristics of the setting in which an incident occurred and the type of individuals involved; cause—the factors and agents that led to an incident; and prevention and mitigation—the measures taken or proposed to reduce incidence and effects of adverse occurrences. These systems describe events with a multidimensional taxonomy to facilitate the comprehensive description and full deconstruction of errors to determine their root causes . However, even if the taxonomy issues of incidence reporting are improved, the problem of determining the true incidence rate remains. A comprehensively described and deconstructed incident only gives insight into the numerator; it does not provide information on the number of patients at risk and does not allow determination of true incidence rates. The denominators are especially difficult to determine because these measurements have major impacts on interpretation ; for instance, C. The numerator data are equally challenging because of the time and expense of chart extraction needed for their collection. If the characteristics of the patient population change over time, then these factors must be accounted for as well. For example, if the patient population changes or new services such as transplantation are offered by a given hospital, then the patient mix will change and adjusted hazard rates will be needed. Although most of these indicators relate to surgical patients, newer indicators are being designed to measure the safety of care for medical patients with critical illnesses, such as myocardial infarction, stroke, and congestive heart failure. Although this method is powerful and can be quite useful, it is important to also recognize its limitations.