Recipient Selection International Guidelines for the Selection of Lung Transplant Candidates were updated in 2006 by consensus agreement of several thoracic societies (summarized in Table 52-8) purchase 10 mg glipizide free shipping diabetes medicine online shopping. Contraindications to lung transplantation are based on their impact on long-term survival discount glipizide 10 mg on-line diabetes type 1 jobs. Patients with severe cardiac disease can be considered for heart–lung transplantation but are not candidates for isolated lung transplant. A Lung Allocation System, developed by the United Network for Organ Sharing, is used, with candidates given a lung allocation score to determine their wait-list status. Lung transplantation is not advocated for acute disease processes, such as acute respiratory distress syndrome. Specific age limits were recommended in the past; however, current guidelines list age more than 65 years as a relative contraindication only. If the patient has been on the waiting list for an extended period, it is important to review recent laboratory and functional data; disease progression may have resulted in change in status since the original workup. Lung transplant candidates have poor pulmonary status and are frequently receiving multiple therapies including oxygen, inhaled bronchodilators, steroids, and pulmonary vasodilators. Although ex vivo lung perfusion is now used in many centers,178,179 the transplant must still be done as soon as a lung becomes available. Because these procedures are done on an urgent or emergent basis, the patient often presents with a full stomach. Although lung transplant patients are understandably anxious, they also have minimal pulmonary reserve, and sedation must be given carefully under monitored conditions. After determining oxygen saturation, slow incremental dosing of a short-acting benzodiazepine (0. Premedication with narcotics such as fentanyl must be administered with extreme caution, if at all, because of their ventilatory depressant effect. Use of metoclopramide, histamine-2 antagonists, and a nonparticulate antacid are usually warranted because of “full stomach” status. Many patients are unable to rest in a supine or in Trendelenburg position for central venous catheterization. Placement of large-bore peripheral intravenous and arterial access is usually adequate for initiation of the anesthetic, with central access achieved after induction. Another option is to place the epidural in the early postoperative period, after coagulopathies are corrected. The epidural can be placed using light sedation during weaning from mechanical ventilation, allowing better neurologic monitoring and pain control prior to tracheal extubation. Other options for postoperative pain relief include postoperative paravertebral blocks, and intercostal nerve blocks performed intraoperatively. Multimodal analgesic techniques, including dexmedetomidine infusion, intravenous acetaminophen, and nonsteroidal anti- inflammatory agents, are now standard components of enhanced recovery after surgery programs. Intraoperative Management Single-lung Transplantation 3691 Lung transplant recipients are often chronically intravascularly volume depleted, and chronic pulmonary hypertension is common. These factors predispose the patients to hypotension and decreased cardiac output on anesthetic induction. Restriction of anesthetic doses because of this concern increases the risk of awareness in this patient population. Monitoring with processed electroencephalography may thus be useful; anesthetic management guided by bispectral index monitoring has been associated with a reduction of the incidence of intraoperative awareness in this population. A balanced technique combining narcotic and inhalation anesthetics or benzodiazepines is usually an effective approach to maintenance of the anesthetic. Possible plans for early extubation should be discussed with the surgeon, and minimizing narcotics while providing multimodal pain relief should be utilized if early extubation is planned. Muscle relaxation can be maintained with rocuronium or vecuronium and is associated with minimal hemodynamic side effects. Nitrous oxide is rarely used because it may exacerbate bullous emphysematous disease, pulmonary hypertension, or intraoperative hypoxemia. Lung isolation, preferably with a double-lumen endobronchial tube, is necessary for single and bilateral sequential lung transplantation. The double- lumen tube, compared to bronchial blockade techniques, allows better suctioning of secretions, improved deflation of the operative lung during dissection, and application of continuous positive airway pressure to the operative lung if indicated. A bronchial blocker is more easily dislodged with surgical manipulation, may not provide isolation of the right upper lobe, and requires repositioning midsurgery in the case of a bilateral sequential procedure. A left-sided endobronchial tube is preferred, because a right-sided tube may be difficult to position relative to the right upper lobe bronchus. Fluid restriction and lung ventilation strategies designed to protect the lung allograft are indicated, because these patients are at increased risk for acute lung injury and pulmonary edema. Strategies to improve oxygenation and ventilation are discussed in detail in Chapter 38. This can be accomplished via either anterior thoracotomy with partial sternotomy or lateral thoracotomy with decreased angulation of the hips to allow access to the femoral vessels. Determination of operative side is based on preoperative ventilation–perfusion studies and prior thoracic surgeries. Circulation is restored to the donor lung, suture lines are checked for hemostasis, and then ventilation is begun. Systemic hypotension can occur during reperfusion but is usually not as significant as that with liver graft reperfusion. The anesthesiologist is often asked to assess the bronchial anastomosis using fiberoptic bronchoscopy and to perform bronchopulmonary toilet on the transplanted lung if necessary (removal of blood, secretions). Along with ex vivo perfusion, Perfadex, a low–molecular-weight dextran solution, improves early graft function and is used widely for preservation during procurement. Pulmonary vein anastomotic obstruction can be diagnosed with careful Doppler examination of the pulmonary venous inflow (see Chapter 27). At the completion of the procedure, the patient should be evaluated for exchange of the double-lumen endotracheal tube to a large (8-mm internal diameter or larger) single-lumen tube. The large diameter facilitates postoperative bronchopulmonary toilet and diagnostic bronchoscopy, as needed. Double-lung Transplantation Bilateral lung transplant is performed in the supine position, using a “clamshell” incision. The arms can be suspended on a padded bar above the patient or tucked at the sides. If the arms are suspended, care must be taken to avoid stretching the brachial plexi. Bilateral sequential transplantation requires lung isolation, preferably via a double-lumen endotracheal tube. Bilateral sequential transplantation is now the preferred procedure because a tracheal anastomosis is unnecessary, and there is less surgical bleeding. Serial implantation implies longer ischemic time for the second lung, but this has not been shown to adversely affect outcome. One hundred and twenty-four pediatric lung transplants were reported worldwide in 2013, compared to only 73 in 1999.
There was also a significant increase in the risk of nonfatal stroke order 10 mg glipizide with visa diabetes diet vegan, as well the risk for significant hypotension and bradycardia buy glipizide 10mg on line diabetic life expectancy, in the group receiving β-blockade. For patients in whom β- blockade was initiated 2 or more days prior to surgery, current data were deemed insufficient to recommend for or against β-blockade therapy in the perioperative period. Further multicenter, randomized controlled trials are needed to address this gap in knowledge. Tachycardia can increase the myocardial oxygen demand (due to increased work) while decreasing supply (due to decreased diastolic filling time), culminating in demand ischemia. Perioperative myocardial ischemia in patients undergoing noncardiac surgery–I: Incidence and severity during the 4 day perioperative period. Studies of perioperative β-blockade specific to the vascular surgery population have found similar conclusions to those in the general surgical population. It further35 concluded that strong evidence suggests that β-blockade increases the risk of perioperative bradycardia and hypotension. As a result of a shift in both the strength and direction of evidence, the practice of β-blocker initiation in the immediate perioperative period has precipitously declined over recent years (Fig. An epidemiologic analysis of nearly 40,000 high- risk patients found a decreased mortality at both 30 days and 1 year in patients who received atenolol as compared to metoprolol. A retrospective37 analysis of nearly 60,000 patients found that both preoperative metoprolol (compared to atenolol) and intraoperative metoprolol (compared to esmolol or labetalol) was associated with an increased risk of stroke after noncardiac surgery. Evidence for the utility of α -agonists in the perioperative period is2 conflicting. Several studies have suggested that the perioperative use of α -2 agonists reduces intraoperative myocardial ischemia, postoperative 2770 catecholamine levels, and mortality in high-risk noncardiac surgery. Despite these42 encouraging results, other evidence calls the perioperative benefit of α -2 agonists into question. Patients receiving α -agonists had more clinically significant hypotension and an2 increase incidence of nonfatal cardiac arrest. Although evidence to support the initiation of α -33 2 agonists is lacking, it is important to recognize that the abrupt discontinuation of this class of medication in patients who are chronic users can result in a rebound sympathetic surge including profound hypertension and tachycardia, diaphoresis, and pulmonary edema. Thus, the relative risks and benefits of continuing versus withdrawing this class of medication must be considered in patients who chronically receive α -agonists. Patterns of beta-blocker initiation in patients undergoing intermediate- to high-risk noncardiac surgery. More recent evidence also suggests more pleiotropic effects on events critical to the surgical stress response. Statins have been shown to inhibit the inflammatory response, reduce ischemia–reperfusion injury, reduce thrombosis, enhance fibrinolysis, decrease platelet reactivity, and restore endothelial function. Meta-analyses specific to the vascular59 surgery population have had conflicting results. A recent retrospective review found that aspirin withdrawal precedes more than 10% of acute cardiovascular events. There was, however, an increased rate of blood loss for all66 procedures and increased transfusion rate for infrainguinal bypass. Of the oral hypoglycemic agents, it is reasonable to hold sulfonylureas due to the risk of hypoglycemia in the settling of preoperative fasting. Metformin is associated with lactic acidosis and should also be held preoperatively due the increased risk of lactic acidosis with hypovolemia and renal dysfunction (which may be comorbid or provoked by iodinated contrast agents used during endovascular procedures). Patients on these medications can be managed with insulin, which is the treatment modality most intensively studied in the perioperative period. Initial work suggested that tight glucose control (glucose 80 to 110 mg/dL) in critically ill patients led to significant decrease in mortality and multiorgan system failure, resulting in a call for stringent control of hyperglycemia in hospitalized patients. Subsequent studies, however, have failed to replicate70 these results and instead have found an increase in unrecognized hypoglycemia and an increased risk of death in patients in the intensive glucose control group. In the intraoperative period, both hyperglycemia (glucose >200 mg/dL) and tight glucose control (glucose <140 mg/dL) have been associated with an increased risk of adverse outcomes. Thus, although severe hyperglycemia should be avoided, it is73 likely prudent to maintain glucose levels in the 140 to 180 mg/dL range 2774 rather than attempt normoglycemia. More recently, two studies have suggested no benefit to liberal (hemoglobin goal 10 to 12 mg/dL) rather than restrictive (hemoglobin goal 7 to 8 mg/dL) transfusion practices. In vascular surgery, specifically, perioperative transfusion has been independently associated with increased 30-day morbidity and mortality. Decision for perioperative transfusion should be77 based on evidence of compromised end organ perfusion, rate and cause of blood loss, and likelihood of obtaining control of ongoing hemorrhage. Hypothermia is also associated with increased adrenergic tone and postoperative myocardial ischemia and events in vascular surgery patients. Therefore,79 aggressive heat conservation and warming measures are appropriate perioperatively. Shivering should be avoided in the perioperative period to prevent increased myocardial demand, and extubation should be postponed in hypothermic patients. Initial observational studies suggested that preoperative cardiac revascularization improves patient outcomes prior to high-risk noncardiac surgery. Monaco and colleagues randomized82 more than 200 patients undergoing vascular surgery to routine preoperative coronary angiography versus selective angiography based on the results of noninvasive testing and risk stratification. Notably, however, long-term survival and freedom from death/cardiovascular events 2775 was improved in the group who underwent routine preoperative coronary angiography (Fig. With aggressive medical therapy (>80% of patients on β-blockers, >70% on aspirin, and >50% on statins in both groups), no long-term benefit was noted with preoperative revascularization. Exclusion criteria in this study included left main disease or ejection fraction less than 20%, thus limiting patients with more severe disease. For patients for whom preoperative coronary revascularization33 is deemed necessary prior to elective surgery, the timing of originally proposed procedure depends on the type of coronary intervention performed. In this case, the clinical urgency of the procedure, medical optimization, and overall fitness of surgery must all be taken into consideration. Systematic strategy of prophylactic coronary angiography improves long-term outcome after major vascular surgery in medium- to high-risk patients: a prospective, randomized study. Physical examination should evaluate for any evidence of end organ involvement (e. It is important to evaluate the control of any comorbid conditions such as diabetes or hypertension. The strong association between smoking and vascular disease mandates a thorough assessment of any underlying pulmonary disease. For any major vascular surgery, it is prudent to obtain baseline laboratory studies. A complete blood count should be obtained due to the risk of major blood loss and possibility of concurrent medical diseases that may predispose to anemia. Coagulation studies should be considered if the patient is on anticoagulant medications or if regional anesthesia is anticipated. A metabolic panel should be obtained due to an increased likelihood of underlying renal insufficiency with resultant electrolyte abnormalities. It is also useful to have a baseline given an elevated risk of postoperative renal dysfunction.
The clinical microbiology laboratory must help drive antibi- otic intervention in partnership with pharmacists and physicians purchase discount glipizide on-line metabolic disease and obesity. Upon presentation of a patient with symptoms of infection buy discount glipizide 10mg online diabetes insipidus peds in review, physicians will seek the primary site of infection and attempt to direct therapy to that primary site. For instance, important factors include the source of infection, community- or hospital-acquired; prior or current medications; recent manipulations or surgery; underlying or chronic diseases; and travel history. Combining a variety of clinical assessments with various laboratory tests from clinical microbiology, hematology, chemistry, point-of-care testing, and blood gas laboratories is an important aspect of the optimum care and treatment of septic patients. Other Evidence-Based Sepsis Guidelines The Surviving Sepsis Campaign is a worldwide consortium of health care providers committed to improving the outcomes for patients with sepsis [21, 30 ]. All compo- nents of the “Surviving Sepsis Campaign Guidelines” are focused on reducing mor- tality by using standardized criteria for patient assessment and treatment. Physicians must place invasive lines and monitor resuscitation of patients closely. Nurses must perform frequent blood draws, manage multiple medications (including pressors), and tailor prescribed therapy based upon a number of parame- ters—some of which may be measured continuously, and some of which require periodic blood draws. Overly sensitive criteria may also lead to over-administration of antibiotics, increasing bacterial resistance and putting patients at risk of experiencing side effects from allergic reaction to organ toxicity. In the event of hypotension and/or lactate >4 mmol/l (36 mg/dl): (a) Deliver an initial minimum of 20 ml/kg of crystalloid (or colloid equivalent). Inspiratory plateau pressures maintained <30 cm H 2O for mechanically venti- lated patients. Drotrecogin alfa (recombinant activated Protein C, aka Xigris) administration was previously listed here, but it has since been withdrawn from use after a major study showed no Xigris efﬁcacy for the treatment of sepsis [31, 32]. Historic Laboratory Methods for Blood Cultures Current laboratory methods for identiﬁcation and characterization of bloodstream pathogens are slow to produce useful results and are ineffective for detection of some pathogens . Rapid detection of bloodstream infections in the critically ill followed by appropriate antimicrobial therapy, can have a life-saving impact. Thus, the development of a rapid, sensitive, and accurate 44 Molecular Niches for the Laboratory Diagnosis of Sepsis 853 molecular diagnostic laboratory method to identify bacterial and fungal pathogens and characterize associated antimicrobial resistance has great potential to beneﬁt diagnosis and therapy for septic patients, and save many lives. In addition, direct susceptibility testing for bac- teria [44–49] and yeast [ 50 ] have been reported. Despite attempts to rapidly identify pathogens and their associated susceptibility, these techniques are still not a common practice and patients and their physicians continue to wait for conﬁrmatory results from blood cultures, the gold standard for diagnosis of bacterial sepsis, which can take several days to grow out a pathogen, limiting their usefulness in the management of the acutely ill patient. Moreover, blood cultures can frequently remain negative even in severe cases of sepsis. For example, routine methods are relatively ineffective for detection of certain patho- gens, such as Coccidioides sp. Despite its large societal impact, historic detection methods for bacteremia and sepsis remain largely unchanged for the past 20 years. Unfortunately, despite the enormous human and ﬁnancial impact of sepsis, its diagnosis remains largely a clinical one , due to the lack of rapid, sensitive, and speciﬁc laboratory tests to detect the causative pathogens. Emerging Molecular Methods for the Diagnosis of Sepsis and Bacteremia In order to provide a more accurate diagnosis, there is a signiﬁcant need to improve the speed and diagnostic breadth of laboratory detection methods for bloodstream infections and sepsis. Routine diagnostic methods, including routine cultures for bacteria, fungi, and rarely, viruses, almost all require subsequent subculture for organism identiﬁcation, and the entire process can take days to weeks to produce a ﬁnal result. Wolk complexities of the host immune response during sepsis, which appears critical to the understanding of associated multiple-organ dysfunction and death. Because of the complex nature of sepsis, there are no single laboratory tests that can combine with clinical information to assess health outcomes or describe a time course of certain key biomarkers. Such a multicomponent test will be the key to unraveling the parallel and complex processes in sepsis and to providing clinicians with a tool for detection, prognosis, and therapeutic monitoring of sepsis. Clearly, historical immunological and molecular methods are impractical for detecting the complex patterns of immune responses seen in sepsis and the wide variety of hematopathogens that can cause disease; therefore clinical microbiology laborato- ries will need to consider the approach of “sepsis diagnostic panels,” to combine detection of hematopathogens and key aspects of host’s innate and systemic immune response. In addition, sensitive genotypic and phenotypic predictors of antibiotic resistance and phamacogenomic markers of potential drug toxicity will play a role in the future. Clearly, it will be critical to offset costs of new rapid methods with overall reduction of hospital costs. In order for the laboratory to effect these changes, a team approach will rely on interaction with pharmacists, physicians, and other health care staff to determine the most judicious use of these methods. One approach may include selective testing on only high-risk patients, which may beneﬁt most from rapid test- ing. Discussion with health care ﬁnance and reimbursement teams as well as antimi- crobial utilization teams are critical for the proper test utilization decisions to be made. In light of the complexity and urgency of the diagnostic challenges we face, this review summarizes the most recent published developments in the diagnosis of sepsis and bacteremia, which impact clinical microbiology laboratories. Probe kit utilization is driven by the gram stain result, thus gram positive cocci in clusters would utilize the S. Recently the probe has been modiﬁed to shorten the hybridization time to 90 min [70, 71 ] At present, enterococci such as E. Use of these algorithms requires targeted interven- tions based on local antibiograms and should not be undertaken without critical review of local antibiograms and pharmacy formulary issues. Reduction in mortality was also observed in a quasi-experimental study per- formed by Forrest et al. In this study, the primary outcome assessed was deﬁned as the “time from blood culture draw to implementation of effective antimicrobial therapy. Comparisons between the pre and post intervention period revealed a decreased 30-day mortality (26 % vs. The Ability to Curtail Unnecessary Antibiotics When Blood Cultures are Contaminated The S. The median hospital cost savings of $19,441 per patient was observed as was a 61 % reduction in antibiotics for coagulase-negative staphylococci, when deemed a blood culture contaminant. Skin and line antisepsis is critical to prevent blood culture contamination and <3 % contamination rate is considered a benchmark of good blood culture collection practice. This study had more discordant samples than other published comparisons, and misidentiﬁcations were observed for S. Support of Antifungal Selection for Candidemia Candida species are the fourth most common cause of nosocomial bloodstream infections, commonly in the immunocompromised host population. Alternatively, guidelines suggest that broad-spectrum agents should be considered for non-C. The majority of the cost savings were realized in antifungal expenditures [61, 76, 77 ]. A total of 114 wound specimens and 406 blood culture bottles were tested from study sites in the United States and Europe in order to characterize assay performance of these assays in a clinical setting. Newly positive blood culture broths with Gram’s stains consistent with gram-positive cocci in clusters were tested. Inhibition was seen with only one sample, and the issue was resolved upon retesting. New Methods with Potential for Future Impact The future of clinical diagnostics is anticipated to include a variety of rapid and multiplex methods.
R. Ramirez. Tougaloo College.