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Evista

By N. Georg. Baldwin-Wallace College.

During labor order 60mg evista mastercard, uterine contractions intermittently reduce perfusion of the placenta 60 mg evista mastercard. If a uterine contraction coincides with a rapid decline in plasma drug concentration after an intravenous bolus injection evista 60mg visa, by the time perfusion has returned to normal 60 mg evista free shipping, the concentration gradient across the placenta has been greatly reduced. Thus, an intravenous injection of diazepam, administered at the onset of contraction compared to during uterine diastole, results in less drug being delivered to the fetus. Several characteristics of the fetal circulation delay equilibration between the umbilical arterial and venous blood, and thus delay the depressant effects of anesthetic drugs (Fig. The liver is the first fetal organ perfused by the umbilical venous blood, which carries drug to the fetus. Substantial uptake by this organ has been demonstrated for a variety of drugs, including thiopental, lidocaine, and halothane. During its transit to the arterial side of the fetal circulation, the drug is progressively diluted as blood in the umbilical vein becomes admixed with fetal venous blood from the gastrointestinal tract, the lower extremities, the head and upper extremities, and finally, the lungs. Because of this unique pattern of fetal circulation, continuous administration of anesthetic concentrations of nitrous oxide during elective cesarean sections caused newborn depression only if the induction-to- delivery interval exceeded 5 to 10 minutes. Rapid transfer of inhalation 2850 agents, including halothane, enflurane, and isoflurane, results in detectable umbilical arterial and venous concentrations after 1 minute. Because of the32 rapid decline in maternal plasma drug concentrations, administration of thiopental or thiamylal as a single-bolus injection not exceeding 4 mg/kg was followed by fetal arterial concentrations of barbiturate below a level that would result in neonatal depression. For example, during asphyxia and acidosis, a greater proportion of the fetal cardiac output perfuses the fetal brain, heart, and placenta. In asphyxiated baboon fetuses, infusion of lidocaine resulted in increased drug uptake in the heart, brain, and liver compared with control fetuses that were not asphyxiated. In this respect, the fetus has an advantage over the newborn in that it can excrete the drug back to the mother once the concentration gradient of the free drug across the placenta has been reversed. With the use of local anesthetics, this may occur even though the total plasma drug concentration in the mother may exceed that in the fetus because there is lower protein binding in fetal plasma. There is only one drug, 2-chloroprocaine, that is metabolized in the29 fetal blood so rapidly that even in acidosis, substantial accumulation in the fetus is avoided. The metabolic clearance in the newborn is similar to, and renal clearance greater than, that in the adult. Elimination half-life is prolonged in the newborn due to a greater volume of distribution of the drug. Prolonged elimination half-lives in the newborn compared with the adult have been noted for other amide local anesthetics. The doses required to produce toxicity in the fetal and neonatal36 lambs were greater than those required in the adult, although serum concentrations at which toxicity occurred were not different. In the fetus, this was attributed to placental clearance of drug into the mother and better maintenance of blood gas tensions during convulsions. In the newborn, a larger volume of distribution was thought to be responsible for the higher doses needed to induce toxic effects. Bupivacaine has been implicated as a possible cause of neonatal jaundice because its high affinity for fetal erythrocyte membranes may lead to a decrease in filterability and deformability, rendering them more prone to hemolysis (see Chapter 41). However, studies have failed to show increased bilirubin production in newborns whose mothers received bupivacaine for epidural anesthesia during labor and delivery. Finally, observational37 neurobehavioral studies have revealed subtle changes in newborn neurologic and adaptive functions. In the case of most anesthetic agents, these changes are minor and transient, lasting for only 24 to 48 hours. Analgesia for Labor and Vaginal Delivery Most women experience moderate-to-severe pain during parturition. In the first stage of labor, pain is caused by uterine contractions, associated with dilation of the cervix and stretching of the lower uterine segment. Pain 2852 impulses are carried in visceral afferent type C fibers accompanying the sympathetic nerves. During the first stage of labor, pain is referred to the T10 to L1 spinal cord segments. In the late first and second stages of labor, additional pain impulses from distention of the vaginal vault and perineum are carried by the pudendal nerves, composed of sacral fibers (S2 to S4). Well-conducted obstetric analgesia, in addition to relieving pain and anxiety, may have other benefits. During the first and second stages of labor, epidural analgesia blunts the increases in maternal cardiac output, heart rate, and blood pressure that occur with painful uterine contractions and “bearing- down” efforts. In reducing maternal secretion of catecholamines, epidural38 analgesia may convert a previously dysfunctional labor pattern to normal. Maternal analgesia may also benefit the fetus by eliminating maternal hyperventilation, which can result in reduced fetal arterial oxygen tension because of a leftward shift of the maternal oxygen–hemoglobin dissociation curve. The most frequently chosen methods for relieving the pain of parturition are psychoprophylaxis, systemic medication, and regional analgesia. Inhalation analgesia, conventional spinal analgesia, and paracervical blockade are less commonly used. General anesthesia is rarely necessary but may be indicated for uterine relaxation in complicated deliveries. Labor varies in length and intensity, as do individual tolerance to pain and desire for pain relief. Women should be educated about the options for labor analgesia and supported in their choice for method of pain control. Neonatal outcomes appear to be similar39 for healthy women who deliver without pharmacologic analgesia and for women who receive analgesia. Nonpharmacologic Methods of Labor Analgesia Nonpharmacologic methods to relieve the pain of childbirth include childbirth education, emotional support, massage, aromatherapy, audiotherapy, and therapeutic use of hot and cold. Conclusions regarding the efficacy of most of these techniques are not possible, as the techniques have been inadequately studied. It provides an educational program on the physiology of parturition and attempts to diminish cortical pain perception by encouraging responses such as specific patterns of breathing and focused attention on a fixed object. Scientific data as to41 whether childbirth education and psychoprophylaxis are effective in reducing childbirth pain are inconsistent and lack scientific rigor. Education, intense motivation, and cultural influences can influence the affective and behavioral responses to pain, although their true effect on pain sensation is less clear. Other Nonpharmacologic Methods Continuous labor support refers to the presence during labor of nonmedical support by a trained person. Prospective, controlled trials and several systematic analyses have concluded that women who receive continuous labor support have shorter labors, fewer operative deliveries, fewer analgesic interventions, and better overall satisfaction. Systematic reviews of42 randomized controlled trials of hydrotherapy (water baths) have concluded that women experience less pain and use less analgesia, without change in the duration of labor, rate of operative delivery, or neonatal outcome.

Similarly evista 60mg, involvement with a facility cheap 60 mg evista otc, a professional staff generic evista 60 mg online, or a multispecialty group goes beyond formal organized governance and committee activity safe 60mg evista. Collegial relationships with professionals of other specialties and with administrators are central to maintenance of a recognized position and avoidance of the situation of exclusion just described. No one individual can be everywhere all the time, but an anesthesiology group or department should strive to be always responsive to any request for help from physicians or administrators. Something as simple as having a departmental telephone extension within the facility that is always answered by a person, whoever it may be, who can direct the caller to the needed help is an extremely effective positive presentation for the facility’s anesthesia professionals. Establishing Standards of Practice and Understanding the Standard of Care The increasing frequency and intensity of “production pressure,” with the36 tacit (or even explicit) directive to anesthesia professionals to “go fast” no matter what, and to “do more with less,” creates situations in which anesthesia professionals may conclude that they must cut corners and compromise safe patient care just to stay in business. Many of these protocols are devised to fast-track patients through the medical care system, especially when an elective procedure is involved, in as absolutely little time as possible, thus minimizing costs. Do these fast-track protocols constitute or establish standards of care 142 that health-care providers must implement? To better understand answers to such questions, it is important to have a basic background in the concept of the standard of care. The standard of care is the conduct and skill of a prudent (or “reasonable”) practitioner that can be expected by a reasonable patient. This is a very important medicolegal concept because a bad medical result due to failure to meet the standard of care is malpractice. Courts have traditionally relied on medical experts knowledgeable about the point in question to give opinions as to what is the standard of care and if it has been met in an individual case. This type of standard is somewhat different from the standards promulgated by various standard-setting bodies regarding, for example, the color of gas hoses connected to an anesthesia machine in the United States or the inability to open two vaporizers on that machine simultaneously. However, ignoring the equipment standards and tolerating an unsafe situation is a violation of the standard of care. Promulgated standards, such as the various safety codes and anesthesia machine specifications, rapidly become the standard of care because patients (through their attorneys, in the case of an untoward event) expect the published standards to be observed by the prudent practitioner. Ultimately, the standard of care for an individual practitioner is what a jury says it is. However, it is possible to anticipate, at least in part, what knowledge and actions will be expected. There are two main sources of information as to exactly what is the expected standard of care. Traditionally, the beliefs offered by expert witnesses in medical liability lawsuits regarding what is actually being done in real life (de facto standards of care) were the main input juries had in deciding what was reasonable to expect from the defendant. The resulting problem is well known: except in the most egregious cases, it is usually possible for the lawyers to find experts who will support each of the two opposing sides, making the process more subjective than objective. Of course, there can be legitimate differences of opinion among thoughtful, insightful experts, but even in these cases the jury still must decide who is more believable, looks better, or sounds better. The second, much more objective, source for defining certain component parts of the standard of care is the published standards of care, guidelines, practice parameters, and protocols that have become more and more common since the idea was originally introduced. These serve as more objective evidence of what can37 be reasonably expected of practitioners and can make it easier for a jury evaluating whether a malpractice defendant failed to meet the applicable standard of care. It has been suggested that the nature of anesthesia practice (having certain central critical functions relatively clearly defined and common to all situations and also having an emphasis on technology) makes it the most amenable of all the fields of medicine to the application of published standards. The Standards for Basic Anesthetic Monitoring document includes clear specifications for the presence of personnel during an anesthetic episode and for continual evaluation of oxygenation, ventilation, circulation, and temperature. This means they are important to practice management because they have profound medicolegal implications: a catastrophic accident occurring while the standards are being actively ignored is very difficult to defend in the consequent malpractice suit, whereas an accident that occurs during well-documented full compliance with the standards will automatically have a strong defense because the standard of care was being met. Various malpractice insurance companies offer discounts on malpractice insurance policy premiums for compliance with these standards, something quite natural to insurers because they are familiar with the idea of managing known risks to help minimize financial loss to the company. Note also that some malpractice insurance companies offer discounts to their insured anesthesia professionals for participating in simulation training, particularly for Crisis Resource Management of clinical emergencies during anesthesia care. Accordingly, the obstetric anesthesia standards were “downgraded” in 1990 to “guidelines,” specifically to remove the mandatory nature of the document. Because there was no agreement as to what should be prescribed as the standard of care, the medicolegal imperative of published standards in this instance has been temporarily set aside. From a management perspective, this makes the guidelines no less valuable because the intent of optimizing care through the avoidance of complications is no less operative. However, in the event of the need to defend against a malpractice claim in this area, it is clear from this sequence of events that the exact standard of care is debatable and not yet finally established (an extremely important medicolegal consideration). This has some of the same elements as a standard of practice but is more intended to guide judgment, largely through algorithms with some element of guidelines, in addition to directing the details of specific procedures as would a formal standard. Beyond the details of the minimum standards for carrying out the procedure, these practice parameters set forth algorithms and guidelines for helping to determine under what circumstances and with what timing to perform it. This thoughtful43 document synthesizes a strategy summarized in a decision tree diagram for dealing acutely with airway problems. The difficult airway algorithm has been discussed extensively in the literature, including suggestions regarding the role of supraglottic airways and, more recently, adding the various airway 145 video imaging technologies. Undoubtedly, the difficult airway algorithm has great clinical value and helps many patients. However, there is concern that as with many modern things, it starts to outdate as soon as it is published. Such considerations are important, both clinically and because all these documents are readily noted by plaintiffs’ lawyers as relevant to establishing the applicable standard of care. This will be decided over time by practitioners’ actions, debates in the literature, mandates from malpractice insurers, and, of course, court decisions. This is clearly not true, yet there is a valid concern that these will someday be held up as defining the standard of care. Accordingly, prudent attention within the bounds of reason to the principles outlined in guidelines and parameters will put the practitioner in at least a reasonably defensible position, whereas radical deviation from them should be based only on obvious exigencies of the situation at that moment or clear, defensible alternative beliefs (with documentation). The most recent type of document has been the “practice advisory,” which can seem functionally similar to a guideline, but appears to have the implication of more consensus compromise than previous documents driven more by meta-analysis of the relevant literature. Even though the desired implication is that practitioners must observe (or at least strongly consider) them, they do not have the same implications in defining the standard of care as the other documents. It may well not be a valid legal defense to justify action or the lack of action because of a company or facility protocol. As difficult as it may be to reconcile with the payer, the practitioner still is subject to the classic definitions of standard of care. The other types of standards associated with medical care are those of the Joint Commission, which is the best-known medical care quality regulatory agency. As noted, these standards were for many years concerned largely with structure (e. Joint Commission standards also focus on credentialing and privileges, verification that anesthesia services are of uniform quality throughout an institution, the qualifications of the director of the service, continuing education, and basic guidelines for anesthesia care (need for preoperative and postoperative evaluations, documentation, and so forth).

Modifications to the King’s College Hospital criteria to improve performance and other prognostic scoring models for specific etiologies have been proposed buy generic evista 60mg on line, such as consideration of serum lactate levels or the addition of an30 apoptosis marker evista 60 mg amex. On the basis of recommendations for septic patients buy evista 60mg lowest price, either norepinephrine or dopamine may be used cheap evista 60 mg with visa. The diagnosis of acute hepatitis is made on the basis of classic signs and symptoms, together with laboratory studies to assess liver damage and serologic assays. Symptoms can be nonspecific, such as fatigue, poor appetite, nausea, vomiting, and abdominal pain, and many infections are subclinical. Signs may include jaundice, or a serum-sickness–type presentation with fever, arthralgia or arthritis, and rash that results from circulating hepatitis antigen– antibody complexes. Incubation periods can be several weeks to even months and patients may undergo surgery without awareness of illness. For this reason viral hepatitis should be part of the differential diagnosis when there is any evidence of postoperative liver injury. Causes of transmission are often not identifiable, but the most commonly known risk factor is parenteral drug use. Encephalopathy may be present in severe alcoholic hepatitis and, if so, portends a poorer prognosis. A history of excessive alcohol use is supportive of the diagnosis of alcoholic hepatitis, but up to 20% of these patients may have a coexisting cause of liver disease. Although liver biopsy is not required to make the44 diagnosis of alcoholic hepatitis, it is important to investigate other potential causes of acute liver disease. For those patients with severe alcoholic hepatitis, medical therapy should also be considered. This consists of nutritional therapy that takes into account not 3253 only protein-calorie nutrition but vitamin and mineral deficiencies as well. R values 2 or less define a cholestatic pattern, and R values between 2 and 5 define a mixed pattern. Drugs may either be directly hepatotoxic or propagate toxic metabolites, most often as products of phase I drug metabolism and the cytochrome P450. Cell injury follows via cell stress, mitochondrial injury,47 or immune-mediated injury. Cell stress may result from glutathione depletion or the binding of reactive metabolites to intracellular enzymes, proteins, or lipids. Immune-mediated injury may result from the binding of reactive metabolites to cell structures, creating antigenic entities that can invoke the formation of antibodies against the cell structures themselves. In anesthesiology perhaps the best known potentially hepatotoxic drug is halothane. Halothane was introduced to patient care in 1956 and, because of its clinical advantages of lack of flammability, potency, and patient tolerance of administration, rapidly enjoyed widespread use. However, reports of postoperative liver injury began to appear shortly thereafter and, by 1963, over 300 cases of “halothane hepatitis” had been reported. The National48 Academy of Sciences produced a retrospective epidemiologic study on the use of halothane from these reports. The National Halothane Study reviewed cases of fatal hepatic necrosis occurring within 6 weeks of the administration of a general anesthetic, from among 34 centers in the United States. Of the 856,000 anesthetics reviewed, about 255,000 involved halothane, and 82 cases of fatal hepatic necrosis were identified. Sixty-three of these cases could be ascribed to an identifiable clinical factor, leaving 19 with otherwise unexplained hepatic necrosis. Fourteen of the nineteen had received a halothane anesthetic, but did not have consistent histologic findings. Uncertainty over the direct association between halothane and the cases of fatal hepatic necrosis, together with the calculated incidence of 1 in 35,000 anesthetics even if such association did exist, led to the conclusion that 3255 halothane overall had a good safety record. The possible association with repeated exposure to halothane did not go unrecognized, and there was an editorial recommendation that halothane be avoided in patients with a history of unexplained fever and jaundice following a general anesthetic. A relatively mild, self-limited form is characterized by elevations in liver-related laboratory studies without evidence of liver failure. A50 proposed mechanism for this hepatocellular damage is the combination of halothane degradation products and hypoxia caused by imbalance in the hepatic oxygen supply–demand relationship. There is strong evidence that51 the severe, fulminant form of halothane hepatitis is an immune-mediated process. The association with repeated halothane exposure and the appearance of rash and eosinophilia support this hypothesis. Because halothane is by far the most extensively metabolized of these agents (20% halothane metabolized vs. Indeed, an animal study examining the extent of hepatic tissue trifluoroacylation after exposure to halogenated anesthetics showed that halothane produced significantly more tissue acylation than enflurane, isoflurane, or desflurane. Liver enzymes may be elevated in 50% of patients,54 with up to 20-fold elevation, but little if any elevation of bilirubin. Therapy is primarily supportive and the condition usually resolves by the second trimester. Intrahepatic cholestasis of pregnancy usually presents in the second to third trimester of pregnancy. The proposed etiology is interference with bile acid transport across the canalicular membrane, resulting in elevated serum bile acid elevation and pruritus. In addition to modest increases in bilirubin (usually <5 mg/dL) aminotransferases may also be elevated up to 20-fold and serum bile acids may be elevated up to 100-fold. As with hyperemesis56 gravidarum, treatment is primarily supportive, aimed at relieving pruritus. Unlike hyperemesis, intrahepatic cholestasis of pregnancy may be associated with chronic placental insufficiency, premature labor, and sudden fetal death. Therefore, pregnancies complicated by intrahepatic cholestasis of pregnancy are considered fetal high-risk pregnancies. The three remaining uniquely pregnancy-related conditions all present in the third trimester. This also leads to areas of hepatic infarction and subsequent hemorrhage, which may coalesce into large hematomas and lead to capsular rupture and intraperitoneal bleeding. Laboratory studies show elevated aminotransferases, up to 10- to 20-fold, and modest increases in bilirubin. Contained hepatic hemorrhage can be managed conservatively with correction of volume deficit and coagulopathy. Capsular rupture or rapid extension of a hematoma is life- threatening and demands more aggressive treatment for control of bleeding, usually emergency laparotomy. Rarely, there may be an indication for transplantation for the patient in whom bleeding cannot be controlled. Therapy remains the same regardless of timing of presentation and most patients will rapidly resolve abnormalities after delivery.

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