By M. Pedar. Union University.
After administration of intravenous heparin buy cheap vastarel 20 mg online, a small side-biting vascular clamp is applied to the artery order vastarel with visa. Perfusion through a graft is safer than direct cannulation of the axillary artery and allows more accurate cerebral perfusion by monitoring the right radial artery pressure buy 20mg vastarel free shipping. During hypothermic circulatory arrest, axillary arterial blood flow is adjusted to maintain a right radial artery pressure of 50 to 60 mm Hg. It is important to monitor radial or brachial artery pressures on the side of arterial cannulation in order to prevent hyper-perfusion of the arm, which can lead to adverse outcomes, including limb loss. The need for any concomitant additional procedures, such as coronary artery bypass grafting, must be noted. When the nasopharyngeal temperature reaches 18°C to 24°C, the patient is placed in the Trendelenburg position. The heart-lung machine is halted, and retrograde cerebral perfusion or selective antegrade axillary perfusion is started. Clamping of the Aorta the aorta should be clamped only if there is a localized aneurysm of the ascending aorta with a generous normal distal segment. Deep circulatory arrest with retrograde cerebral perfusion is used when the ascending aortic aneurysm fades away into the arch or involves the arch as well, as in all patients with aortic dissection. Aortic Cross-Clamp Injury Application of a clamp to the aorta in the presence of acute aortic dissection further traumatizes the aortic wall. In addition, it may pressurize the false lumen and result in progression of the dissection and possible obstruction of some aortic branches or even aortic rupture. They must be carefully removed along with atherosclerotic debris to prevent possible subsequent embolization. Myocardial Protection Cold blood cardioplegic solution may be administered antegrade into each coronary artery if deemed necessary. This is especially important if the dissection has involved one of the coronary ostia because the myocardium fed by this vessel may not have cooled sufficiently owing to obstructed flow. If the cardioplegic line is used for the retrograde cerebral perfusion with cold blood, this will have to be delayed until the cardioplegic infusion is completed and the line purged of cardioplegic solution. The dissection may have extended into the aortic arch and the aortic root involving a coronary ostium, most commonly that of the right coronary artery. The divided aortic wall may at times be left in situ to be reapproximated loosely over the tube graft at the completion of the procedure. Typically, the lesser curvature of the aortic arch is resected to remove as much diseased aorta as possible. A 1- cm cuff of relatively normal aorta is dissected with as much adventitial tissue as possible left intact for the distal anastomosis. Reinforcement of the Aortic Wall If the distal aortic wall is dissected, BioGlue Surgical Adhesive (CryoLife, Inc. The sponge within the lumen of the aorta is gently pressed against the aortic wall in close proximity to the coronary ostia to prevent the glue material from occluding the coronary arteries. Glue Embolization Glue material is not introduced within the dissected distal wall of the aorta if there appears to be reentry sites within the aortic arch. The possibility of glue material becoming detached and embolized through the distal reentry site is a grave complication of this procedure. Further reinforcement can be obtained with Teflon felt strips attached to both the inside and/or outside of the aortic wall first with 6 to 10 interrupted mattress sutures or a continuous mattress suture of 3-0 Prolene. Teflon felt strips may not be required if the integrity of the aortic wall appears to be satisfactory with the glue. Alternatively, the outer adventitial layer of the dissected aorta can be cut longer than the inner intimal layer. This layer is then folded into the true lumen and sewn in place with interrupted mattress sutures. An appropriately sized Hemashield tube graft is cut and tailored obliquely to be attached to the undersurface P. The tube graft is then anastomosed to the reinforced aortic cuff with a continuous 3-0 Prolene suture. Tension on the Suture Line It is important for the assistant surgeon to follow the suture meticulously to provide appropriate tension on the suture line. Otherwise, multiple reinforcing interrupted sutures may be required to ensure a watertight anastomosis. With the patient in the Trendelenburg position, the perfusion of retrograde cerebral blood is allowed to accumulate and fill the aortic arch. At this time, another arterial cannula is introduced through the tube graft, and the perfusionist is asked to initiate arterial perfusion through this cannula in an antegrade manner with extremely low flow. A clamp is now applied to the tube graft well away from the anastomosis and proximal to the cannula, and the retrograde cerebral perfusion is gradually discontinued and venous drainage is reinstituted. The posterior distal suture line is now examined, and additional stitches are placed for control of hemostasis if required. In patients with aortic aneurysm, the femoral arterial cannula may be used to reinstate cardiopulmonary bypass. While not essential, antegrade perfusion with a separate cannula through the tube graft allows earlier removal of the femoral arterial cannula and repair of the femoral artery, reducing the risk of limb ischemia. Retrograde Arterial Perfusion and Aortic Dissection In patients with aortic dissection, blood gains access through the entry site into the aortic wall. This dissection may result in a reentry site by tearing the intima distally along the course of the aorta. When cardiopulmonary bypass is reinitiated, the retrograde flow may enter the false lumen through this distal intimal tear and reenter the lumen at the entry site. However, when the aorta has been repaired and the entry site is excluded by tube graft interposition, the retrograde flow of blood cannot escape and may cause further dissection of the aorta. Therefore, it is important to establish antegrade flow within the true lumen when resuming cardiopulmonary bypass. If right axillary artery cannulation has been used, the tube graft can be filled by removing the clamp on the innominate artery. After cardiopulmonary bypass is reestablished, additional doses of blood cardioplegic solution are administered by the retrograde technique and antegrade into the P. When the aorta is otherwise normal and there is no aortic valve insufficiency, the proximal aorta that has been transected at approximately 1 cm above the level of aortic commissures is reinforced with glue and a single or double layer of Teflon felt, as described for the distal anastomosis. The tube graft is tailored to an appropriate length and anastomosed to the proximal aorta with 4-0 Prolene continuous suture. Often, however, there may be associated aortic insufficiency due to aortic root dissection or dilation. When the valve leaflets are not diseased and the remainder of the aortic root is normal, every attempt is made to retain the aortic valve. Any incompetent commissure is resuspended by curing the dissected root with BioGlue and reinforced with an external felt strip. Usually, a single pledgeted Prolene suture is placed immediately above each of the commissures and tied down in order to resuspend the commissural posts further. This tailored proximal anastomosis reestablishes a new sinotubular junction, incorporating the resuspended commissures to ensure a competent aortic valve.
Silastic tubes are either right angled or straight; have multiple drainage holes; and contain a radiopaque stripe with a gap to mark the most proximal drainage hole purchase vastarel 20mg with visa. They are available in sizes ranging from 6 to 40 Fr buy discount vastarel online, with size selection dependent on the patient population (6 to 24 Fr for infants and children) and the collection being drained (24 to 28 Fr for air; 32 to 36 Fr for pleural effusions; and 36 to 40 Fr for blood or pus) buy 20mg vastarel with visa. Small-caliber Silastic tubes have been increasingly employed for chest drainage, particularly after open-heart surgery, to decrease pain and allow earlier ambulation . Before performing the procedure, it is important to review the steps to be taken and to ensure that all necessary equipment is available. The first two direct techniques require a surgical incision and are (a) blunt dissection and (b) trocar puncture. With the patient supine and the head of the bed adjusted for comfort, the involved side is elevated slightly with the ipsilateral arm brought up over the head. This area is bordered by the anterior border of the latissimus dorsi; the lateral border of the pectoralis major muscle; a line superior to the horizontal level of the nipple; and the apex below the axilla . The tube is usually inserted through the fourth or fifth intercostal space in the anterior axillary line. An alternative entry site (for decompression of a pneumothorax) is the second intercostal space in the midclavicular line, but for cosmetic reasons and to avoid the thick pectoral muscles, the former site is preferable in adults. Under sterile conditions, the area is prepped in standard sterile fashion; and it is draped to include the nipple, which serves as a landmark, as well as the axilla. A 2- to 3-cm area is infiltrated with 1% lidocaine to raise a wheal two finger-breadths below the intercostal space to be penetrated. A 2-cm transverse incision is made at the wheal, and additional lidocaine is administered to infiltrate the tissues through which the tube will pass, including a generous area in the intercostal space (especially the periosteum of the ribs above and below the targeted interspace). Care should be taken to anesthetize the parietal pleura fully, because it (unlike the visceral pleura) contains somatic pain fibers. Each injection of lidocaine should be preceded by aspiration of the syringe to prevent injection into the intercostal vessels. To confirm the location of air or fluid, a thoracentesis is then performed at the proposed site of tube insertion. A short tunnel is created to the chosen intercostal space using Kelly clamps, and the intercostal muscles are bluntly divided. The closed clamp is carefully inserted through the parietal pleura, hugging the superior portion of the lower rib to prevent injury to the intercostal bundle of the rib above. The clamp is placed to a depth of less than 1 cm to prevent injury to the intrathoracic structures, and is spread open approximately 2 cm. A finger is inserted into the pleural space to explore the anatomy and confirm proper location and lack of pleural symphysis. The end of the chest tube is grasped with the clamp and guided with the finger through the tunnel into the pleural space. Once the tip of the tube is in the pleural space, the clamp is removed, and the chest tube is advanced and positioned apically for a pneumothorax and dependently for fluid removal. The location of the tube should be confirmed by observing the flow of air (seen as condensation within the tube) or fluid from the tube. A simple suture to anchor the tube can be used, or a horizontal mattress suture can be used to allow the hole to be tied closed when the tube is removed. An occlusive petrolatum gauze dressing is applied, and the tube is connected to a drainage apparatus and securely taped to the dressing and to the patient. The end of the chest tube is grasped with a Kelly clamp and guided with a finger through the chest incision. In one series, insertion and management of pleural tubes in patients with blunt chest trauma carried a 9% incidence of complications. Major complications requiring surgical intervention, or administration of blood products or intravenous antibiotics occurred in only four (1. The use of small-caliber, less rigid, Silastic drains has been found to be as safe and efficacious as the more rigid, conventional chest tubes . Most institutions use a three-chambered system that contains a calibrated collection trap for fluid; an underwater seal unit to allow escape of air while maintaining negative pleural pressure; and a suction regulator. Suction is routinely established at 15 to 20 cm water, controlled by the height of the column in the suction regulator unit, and maintained as long as an air leak is present. The drainage system is examined daily to ensure that appropriate levels are maintained in the underwater seal and suction regulator chambers. Connections between the chest tube and the drainage system should be tightly fitted and securely taped. For continuous drainage, the chest tube and the drainage system tubing should remain free of kinks; should not be left in a dependent position; and should never be clamped. Routine milking and stripping of chest tubes is discouraged primarily in postoperative cardiac surgical patients. Dressing changes should be performed every 2 or 3 days and as needed, making sure that no dressing with high content of petroleum-based ointment is present, because this would macerate the skin around the chest tube insertion site. Adequate pain control is mandatory to encourage coughing and ambulation to facilitate lung reexpansion. If the patient develops clinical symptoms including shortness of breath, decreasing oxygen saturation, or subcutaneous emphysema, then radiographic evaluation is indicated . A tube should never be readvanced into the pleural space, and if a tube is to be replaced, it should always be at a different site. If an air leak persists, brief clamping of the chest tube can be performed to confirm that the leak is from the patient and not from the system. When the leak has ceased for more than 24 to 48 hours (or if no fluctuation is seen in the underwater seal chamber), the drainage system is placed on water seal by disconnecting the wall suction, followed by a chest film several hours later. If no pneumothorax is present and no air leak appears in the system with coughing; deep breathing; and reestablishment of suction, the tube can be removed. For fluid collections, the tube can be removed when drainage is less than 200 mL per 24 hours , unless sclerotherapy is planned. When the chest tube is removed, the lungs should be fully expanded, which minimizes the pleural space. This can only be achieved when the patient holds his/her breath while performing the Valsalva maneuver (i. Variation of success rates could be affected by a number of reasons including the underlying disease, the use of mechanical ventilation, or other factors . Also, there have been reports of successful management of small and large pneumothoraces with small size (8. Thirty-six (60%) patients were discharged after 4 hours, and 30 patients (50%) were managed as outpatients. Because evacuation of a pneumothorax and removal of pleural fluid are the main indications for chest tube insertion, ultrasonography has application for chest tube insertion and care. The linear high frequency probe lacks sufficient penetration to visualize deeper thoracic structures such as atelectatic lung underlying the pleural effusion, but is useful for identification of lung point while mapping out the extent of a pneumothorax. A free-flowing pleural effusion will assume a dependent position in the thorax owing to gravitational effect, so the operator examines for fluid over the lateral chest in the supine patient. The operator can readily locate a loculated effusion and insert a targeted chest tube for drainage of the pleural fluid .
Hemodynamic Hemodynamic physiologic changes occur as a result of the need to ensure adequate tissue perfusion to vital organs buy vastarel 20mg with amex. This is accomplished at the outset of severe hemorrhage through a multitude of cardiovascular mechanisms proven 20mg vastarel, led by sympathetic upregulation buy cheap vastarel 20mg online. Sympathetic outflow resulting from atrial and carotid body baroreceptors and loss of vagal tonic inhibition as a function of hypovolemia, causes cardiac chronotropic and inotropic responses. Epinephrine increases heart rate, which in turn maintains cardiac output, despite falling stroke volume. This is first recognized clinically by an increase in diastolic pressure, and consequent narrowed pulse pressure. With worsening hypovolemia, respiratory variations in pulse pressure may develop, worsening mean perfusion pressures significantly. Decreased arterial and venous compliance secondary to epinephrine release improves venous return in the face of hypovolemia. Consequently, renal blood flow is decreased to only a fraction of normal levels, leading to acute kidney injury and oliguria. On a microvascular level, increases in cellular adhesion molecules cause neutrophils to adhere to the endothelial cells in the microcirculation, limiting the physical ability of red cells to navigate capillary beds. Inflammatory mediators induce endothelial cell swelling, further limiting the passage of blood constituents. Decreases of capillary flow provoke cellular ischemia and anaerobic metabolism with ensuing acidosis . Vasoconstriction is maximized through exponential quantities of endogenous catacholamines; however, without volume, it is to no avail. Acidosis rapidly follows, heart rate variability declines, and bradycardia emerges signifying irreversible shock. The remaining intravascular volume is deplete of hemoglobin mass, although concentrations may remain relatively stable in the initial phases. To counteract this, oxygen extraction increases, measured by declining mixed venous oxygen saturation, and the patient becomes dependent upon oxygen delivery to maintain aerobic metabolic pathways and stave off impending acidosis. As hemorrhage continues and the previously described hemodynamic changes occur, anaerobic metabolism begins to materialize. The resultant acidosis shifts the oxygen dissociation curve to the right, favoring oxygen offloading at the cellular level. Mild acidosis, therefore, executes a beneficial effect, curbing progressive anaerobic transformation temporarily. If hemorrhage control is not accomplished, the availability of cellular oxygen fades, and mitochondrial energy production is halted with accumulation of pyruvate. Lactic acidosis then ensues until oxygen delivery restores the electron transport chain, at which time pyruvate may reenter the citric acid cycle and lactate production decreases. This large energy gap cannot be replenished without resumption of normal physiologic metabolism, which requires restoration of oxygen delivery through hemorrhage control and resuscitative efforts. Cortisol not only aids in vasoconstriction but also promotes glucose release in large quantities to combat essential cellular starvation as a result of hypoperfusion. Hyperglycemic deleterious effects are far reaching, and include increased infection and elevated intracranial pressure. Regarding direct correlation to hemorrhagic shock, however, hyperglycemia may result in osmotic diuresis despite decreased renal blood flow and glomerular filtration rate augmented by renin–angiotensin–aldosterone system activation, thereby worsening the already depleted intravascular volume. Immunologic Hemorrhagic shock results in a multitude of immune responses related to the upregulation of cellular signaling designed to protect, but often result in harm. Extensive research in the last decade has shown that hemorrhagic shock activates inflammatory cascades, resulting in profound abnormalities. However, there have been no clear data regarding which of the many involved substances plays the key role in development and propagation of the overactive inflammatory response. One of the major areas of study involves the activated immune response that results in enhanced activation and adhesion of leukocytes. During this activated stage, neutrophils can release harmful reactive oxygen species, which are thought to play a major role in loss of capillary integrity. Additionally, immunologic responses to therapy, specifically large-volume crystalloid infusion, may trigger the altered immune response to hemorrhage and has been a growing area of research . Every patient who is at risk for hemorrhage should be evaluated through methods delineated in the Advanced Trauma Life Support program. By quickly proceeding through the primary survey (evaluation), immediate life threats are recognized and can be treated . This presents a departure from traditional methods of initial patient evaluation of taking a long, thorough history from the patient, discussing options, and planning a workup. A hemorrhaging patient does not have the luxury of time, and delayed recognition of shock often results in death. Immediate threats to life must be identified early, and minor injuries or findings must not derail the primary goal of addressing potentially lethal matters. Basic physical examination skills utilized in context often form a clinical impression that leads to the diagnosis. Heart rate and blood pressure, which are often used in the incorrect definition of shock, may be normal. A narrowed pulse pressure, however, is typically present, and often missed owing to a normal systolic value. Anxiety or belligerence may be a sign of shock, and can easily be confused for intoxication or isolated brain injury. Cool, clammy extremities in a patient at risk for shock are clinical markers for peripheral vasoconstrictive compensation. Hypothermia, a key component of the lethal triad (hypothermia, coagulopathy, and acidosis) is an independent predictor of mortality in hemorrhaging patients. For example, hemoglobin and hematocrit levels are frequently normal, because the laboratory result is a measure of concentration—which remains unchanged until compensatory mechanisms and interstitial to intravascular fluid shifts have occurred. However, when a hemoglobin of less than 11 g per dL is present, it is associated with a mortality rate of nearly 40% . This makes the arterial blood gas quite useful, because any acid– base abnormality can be presumed to be caused by the event that brought the patient to the hospital, and not underlying medical conditions. Tissue oxygen saturation continues to be investigated as a simple, reliable, and early marker of the presence of hemorrhagic shock . For the injured patient, chest and pelvic radiographs may be of great utility because they can help identify major hemorrhage in two of the five key locations where deadly hemorrhage may occur. In nontrauma cases, a nasogastric tube may be inserted for suspected gastrointestinal hemorrhage to aid in localization. Endoscopy and interventional radiologic methods may also be employed emergently as conditions warrant. Transient response conveys ongoing hemorrhage, and beseeches health care providers to act quickly to obtain hemorrhage control.
Other diseases caused by agents of bioterrorism and endemic diseases can be identified by examination of respiratory secretions buy vastarel on line. Cultures A definitive etiologic diagnosis of pneumonia can be made when cultures of blood 20mg vastarel fast delivery, pleural fluid generic 20 mg vastarel mastercard, or spinal fluid are positive in the presence of a lung infiltrate and a compatible clinical picture. Sputum cultures can be difficult to interpret because of the problem of separating infection from colonization among the critically ill. Among intubated patients, colonization is present after several days, so the culture should be interpreted in the clinical context of the patient, and a sample should not be cultured in the absence of clinical signs of infection. Viruses may be cultured from respiratory secretions, but this procedure may take up to 20 days, depending on the virus. Thus, cytologic evidence of viral infection that can be recognized sooner may provide helpful information. Invasive Diagnostic Sampling and Quantitative Cultures Because of the inherent problems distinguishing colonizing from infecting pathogens in samples of lower respiratory tract secretions, investigators have advocated for the collection of deep respiratory secretions through invasive (bronchoscopic) or semi-invasive (catheter- lavage) means, combined with analysis of the results using quantitative cultures. They found no difference of mortality between the two groups, and similar rates of adjusting antibiotic therapy after initial empiric management. Unlike an earlier study, in this investigation, all patients initially received antibiotic therapy, so cultures were used to adjust antibiotics but never to withhold them. Lower respiratory tract cultures can be obtained bronchoscopically or nonbronchoscopically and can be cultured quantitatively or semiquantitatively. Regardless of which method is used, it should only be initiated once the clinician has made a clinical diagnosis of pneumonia and is ready to initiate therapy. Therapy should be prompt and not delayed for the purpose of collecting a diagnostic sample, especially for patients who are clinically unstable or septic from pneumonia . Percutaneous needle aspiration of the lung in an area of infiltrate has also been studied, but it is limited by a high incidence of false-negative results and an unacceptable complication rates, including pneumothorax in up to 30% of patients and a 10% rate of hemoptysis. Although open lung biopsy is the unequivocal standard for the diagnosis of infection, it has been applied primarily for the immunocompromised host with rapidly advancing, life-threatening infection. Various patterns with B and M mode ultrasound techniques including—“tissue sign” and “dynamic airbronchograms” are seen with pulmonary consolidation. Purulent respiratory secretions (defined as secretions from the lungs, bronchi, or trachea that contain >25 neutrophils and <10 squamous epithelial cells per low power field [lpf, ×100]; If the laboratory reports semiquantitative results, those results must be equivalent to the above quantitative thresholds). Positive culture (qualitative, semiquantitative or quantitative) of sputum, endotracheal aspirate, bronchoalveolar lavage, lung tissue, or protected specimen brushing. An increasingly common problem is the differentiation of acute infectious pneumonia from drug-induced pneumonitis caused by agents such as amiodarone, bleomycin, busulfan, methotrexate, and newer cancer treatments, such as immune checkpoint inhibitors. Among immunocompromised patients, a new lung infiltrate may represent infection, progression of the underlying primary disease, or drug-induced lung disease. Many have suggested that tuberculosis is poorly recognized in the intensive care setting and should be considered for patients with a history of inadequately treated tuberculosis or radiographic evidence of previous infection. Patients with impaired B-cell function such as multiple myeloma are particularly prone to pneumonia with encapsulated organisms, including pneumococcus and H. A similar organism profile can be seen among splenectomized patients and among those with complement defects. Even in the setting of established pneumonia, patients may have a second infectious process such as extrapulmonary infection (catheter-associated bacteremia) or complications of antibiotic therapy, such as antibiotic-induced colitis. Many of the commonly applied measures are based on traditional practice, with little documentation of efficacy. Nutritional Support Evidence implicating malnutrition as a cofactor for pneumonia is substantial, but the evidence that nutritional intervention alters the outcome of severe pneumonia is lacking . Enteral nutrition is preferred, if this can be practically accomplished, because data suggest better preservation of immune function using this route compared with total parenteral nutrition . When enteral feedings are given, a small- bore tube, preferably placed in the small bowel, should be used along with a continuous infusion method to prevent aspiration and to optimize the delivery of calories . All patients should be kept semierect (greater than 30 degrees upright) and not supine as much as possible, to reduce the risk of reflux and aspiration . Chest Physiotherapy There is little support for the routine application of chest physiotherapy in patients who have an effective cough and scant amounts of respiratory secretions. Because of the labor-intensive nature of this intervention, techniques such as percussion, vibration, and postural drainage should be specifically targeted to patients with large volumes of purulent secretions (>30 mL per day) and an ineffective clearance by coughing. Aerosols and Humidification Humidification has been a traditional practice of respiratory therapy aimed at reducing sputum viscosity and promoting mucociliary clearance. Because the deposition of water vapor depends on particle size and the degree of airway obstruction, it is likely that most aerosols are deposited above the glottis and act only to stimulate cough. Although mucolytic agents such as acetylcysteine offer the theoretic benefit of reducing the viscosity of purulent secretions, they may act as irritants that can provoke bronchospasm, and thus must be used selectively. Bronchodilator therapy with β2 agents can enhance mucociliary clearance and ciliary beat frequency, but there have been no controlled trials that have demonstrated improved outcomes with their use for pneumonia, in the absence of underlying bronchospasm. Because it is often impossible to identify a specific etiologic agent at the time that therapy is started, initial therapy is necessarily empirical but can be modified and focused (de-escalated) once the results of diagnostic testing become available. Community-Acquired Pneumonia Because the use of clinical syndromes or sputum Gram stain to guide therapy is often inaccurate and not recommended, initial therapy is empirical, based on the likely etiologic pathogens. For selected patients, particularly following influenza or other viral infections, empirical therapy for S. Every patient should receive therapy directed at these organisms, which can be either as a primary pathogen or copathogen, but studies have shown that the use of a macrolide may be of specific value. In patients with bacteremic pneumococcal pneumonia, particularly in those with severe illness, dual therapy including a macrolide has been associated with improved outcomes [123,124]. A quinolone can also be used to treat atypical pathogen infection and may have an advantage for the patient with suspected Legionella infection, where the outcomes using quinolones have been exceptionally good . For these patients, therapy can be a two-drug regimen, using a selected antipseudomonal β-lactam (cefepime, piperacillin/tazobactam, imipenem, and meropenem), in combination with an antipseudomonal quinolone (ciprofloxacin, high-dose levofloxacin 750 mg daily). Alternatively, the above-mentioned β-lactams can be combined with an aminoglycoside and either azithromycin or an antipneumococcal quinolone (levofloxacin 750 mg or moxifloxacin 400 mg). For the penicillin-allergic patient, aztreonam can be combined with an aminoglycoside and an antipneumococcal fluoroquinolone . Occasionally, these broad-empiric approaches should be modified, particularly when clinical or culture data suggest an organism that is not included in the initial regimen (e. In addition, certain comorbidities predispose to specific pathogens, and these should be covered by the chosen empiric regimen (see Table 181. However, there was survival advantage for patients, who had initial adequate antibiotic therapy and those who received dual therapy had a higher frequency of initial adequate antibiotics. Although there was no mortality difference in favor of the fluoroquinolones, for patients with more severe pneumonia, those who required hospitalization and those requiring intravenous therapy, the quinolones were more effective . If highly resistant pneumococcus (but not cephalosporin resistant) is documented and meningitis is present, therapy should be initiated with vancomycin, cefotaxime, or ceftriaxone.
The surgical treatment of these patients is usually limited to relief of recurrent effusions by subxiphoid pericardial drainage or a pericardial window procedure purchase vastarel 20mg otc. Right Atrial Extension of Tumors below the Diaphragm Abdominal and pelvic tumors may invade and grow up the inferior vena cava to reach the right atrium purchase vastarel overnight. It may be feasible to withdraw the tumor from the subdiaphragmatic inferior vena cava transabdominally discount 20mg vastarel visa. If this is not possible, a median sternotomy is performed and cardiopulmonary bypass achieved for systemic cooling. During a short period of deep hypothermic circulatory arrest, the right atrium is opened, and the cardiac surgeon assists the urologist to withdraw the tumor down into the abdominal segment of inferior vena cava and remove it. Cardiopulmonary bypass is reinstituted, the patient is rewarmed, and weaned from bypass in the usual manner. Cannulation of Right Atrium A large straight or right angled venous cannula is placed through a purse-string suture into the right atrium for a limited distance to avoid contact with the tumor. Coagulopathy These patients have significant problems with coagulopathy following cardiopulmonary bypass with profound hypothermia. This technique should be reserved for patients in whom the tumor cannot be removed through the inferior vena cava just below the diaphragm. James Cox and has proved to be effective for treating atrial fibrillation associated with valvular and ischemic heart disease and isolated atrial fibrillation refractory to medical therapy. However, this procedure adds significantly to the aortic clamp time and incurs the risk of serious bleeding from the back of the heart. The ideal energy source for performing a full or partial Maze procedure should be fast and produce a transmural lesion without causing damage to surrounding structures. It would be advantageous if it could be applied through a minimally invasive approach without the use of cardiopulmonary bypass. Unipolar systems have been modified by adding irrigation to minimize the surface charring, which can lead to thrombus formation, and to prevent injury to adjacent structures, particularly the esophagus. Bipolar radiofrequency clamps can be used epicardially, assure transmural lesions, and avoid damage to surrounding tissue. Microwave produces conduction block by thermal injury, but unlike radiofrequency, it does not cause surface charring. Focused ultrasonography results in deep heating and coagulati on necrosis, and can be delivered through tubular or planar transducers. Patients with chronic atrial fibrillation undergoing mitral valve surgery are candidates for this procedure, which adds approximately 20 minutes to the cross-clamp time. The initial right atrial incisions and lesions are accomplished on cardiopulmonary bypass with a beating heart. These two lesion sets are usually performed with bipolar radiofrequency clamp on the free wall to save time. Omitting Right Atrial Ablation Lines It is generally agreed that most of the right-sided lesions are not required in most patients. However, the ablation line from the coronary sinus inferiorly into the inferior vena cava should probably be included to prevent right atrial flutter. After placing a retrograde cardioplegia catheter, we then close the right atriotomy and start the left-sided lesion set. Left atrial appendage is amputated and through the opening, a lesion is created between the left atrial appendage opening and left superior pulmonary vein. We then mark the coronary sinus with a marking pen between the right and left coronary artery circulations. A standard left atriotomy is performed, with extension superiorly into the dome of left atrium or inferiorly around the right inferior pulmonary vein. Using the bipolar clamp, a lesion is created from the inferior aspect of the atriotomy to the inferior left pulmonary vein. Similarly, another lesion is created toward the mitral valve annulus and across the coronary sinus. Lastly, the epicardial cryoablation of the coronary sinus is performed to complete the mitral isthmus ablation. Patent Foramen Ovale If a patent foramen ovale or small atrial septal defect is present, the right atrial lesions must be performed after the aorta is cross-clamped or with induced ventricular P. The absence of a patent foramen ovale must be confirmed by transesophageal echocardiography in the operating room before instituting cardiopulmonary bypass. Transmural Lesions the bipolar radiofrequency clamp has the distinct advantage of increasing the likelihood of transmural lesions. Bleeding from the Base of the Left Atrial Appendage If the base of the appendage is ablated with the radiofrequency probe and then the appendage is amputated and oversewn, the ablated tissue may tear when the heart fills with blood and contracts. The appendage should be either surgically amputated or ablated with radiofrequency energy, not both, to avoid this complication. Thrombus in the Left Atrial Appendage If thrombus is present in the left atrial appendage, it should be amputated. Stenosis of the Pulmonary Vein Orifices the healing process that takes place after radiofrequency ablation may lead to fibrosis and contraction of tissue. The lesions surrounding the orifices of the pulmonary veins should be well within the left atrium to avoid subsequent scarring and pulmonary vein stenosis. Therefore, care must be exercised when creating lesions extending onto the tricuspid and especially the mitral valve annulus. Because of this concern, some surgeons prefer to use a cryoprobe to make these lesions because cryoablation does not permanently damage leaflet tissue. It is also important to carry out these lesions before any valve repair or replacement procedure is performed. Injury to the Circumflex Coronary Artery In performing the ablation from the left pulmonary veins to the mitral annulus, care must be taken because the circumflex coronary artery underlies this area. Alternatively, the risk of damaging the artery can be reduced by maintaining flow through the vessel during the ablation. Injury to the Esophagus Esophageal injury has been seen with dry radiofrequency ablation of the posterior left atrial wall. The goal of any energy source used to create lines of ablation is to achieve transmural lesions without injuring adjacent tissues and structures. Thrombogenic Foci Ablation lines created by some energy sources have been reported to result in thrombus formation within the left atrium. It may be prudent to anticoagulate all patients, regardless of cardiac rhythm, with warfarin for at least 3 to 6 months to prevent this devastating complication. The bipolar radiofrequency clamps can be used to create the pulmonary vein encircling lesions on a beating heart. This procedure can be safely and quickly performed in patients with atrial fibrillation undergoing coronary bypass or aortic valve operations. Many surgeons perform a modified left-sided Maze, which may or may not include the lesion connecting the pulmonary vein encircling lines and/or the ablation line from the left pulmonary vein encircling lesion to the mitral annulus.