By Y. Hurit. Allegheny College. 2019.
She had recently delivered a H substance generic kamagra 50mg on-line, which is a precursor for the for- stillborn infant with hemolytic disease purchase kamagra 100 mg on line. The new be administered only when the benefits over type of antibody described by Levine and weigh the risks buy kamagra 50mg low cost. Levine Transfusion Transmitted Diseases and his colleagues (1941) proved that Rh sen- sitization was the cause of hemolytic disease Iatrogenic diseases are transmitted through of the newborn. The blood may contain bacteria, virus, parasite or neoplastic cells, Fisher postulated that Rh antigens are de- which may inadvertently, negligently, acci- termined by three pairs closely linked allelo- dentally or through faulty screening tech- morphic genes, Cc, Dd and Ee. En- vidual possesses one member of each pair of dotoxins of gram-negative bacteria, which these genes derived from each parent. Parasites like malaria parasite approximately 93 percent are Rh positive and and spirochete such as Treponema pallidum 7 percent are Rh negative. CdE Rhy 228 Textbook of Immunology Sensitization of Rh mother to Rh-positive- Hemolytic Transfusion Reactions Hemolytic transfusion reactions occur after erythrocytes usually occurs during birth of the first Rh+ infant. An increasing there will be fever, chill, facial flushing, chest risk of subsequent infants being affected, as pain, hypotension, nausea, vomiting, hemo- the mother is desensitized with each succes- globinuria, anuria, oliguria and shock. The Rh moth- of mismatched blood, there is agglutination, ers destroy the Rh+ erythrocytes more rap- complement activation and intravascular idly, as they are Rh incompatible as well as hemolysis (Table 16. Hyperacute graft rejection oc- curs when a graft recipient has preformed an- antibodies to their own erythrocytes (blood tibody against the grafted tissue. The autoimmune hemolytic anemia can These antibodies cross the placenta and re- be divided into three types, depending upon act with the fetal erythrocytes, causing their the nature of antibodies produced against destruction (Figs 16. Erythrocytes from Rh+ (RhD+) fetus leak into the maternal circulation usually during Warm-reactive Autoantibodies birth. If mother is Rh– this stimulates produc- Autoantibodies react with antigen at 37°C tion of anti-Rh antibody of the IgG class. In the first pregnancy of Rh- negative mother, the baby is normal, but Rh positive and at some point (e. During subsequent pregnancies, the IgG antibodies cross the placenta and cause fetal anemia and heart failure; C. Prevention relies on removing the red cells, as they cross the placenta by administering anti-Rh antibody to the mother, e. This prevents sensitization, but must be given in all subsequent pregnancies as well. They are ule components may also act as antigen in specific for Ii blood group system. Most cold Autoantibodies to platelets reactive autohemolytic anemia occurs in old Autoantibodies to platelets are formed in people. It is thought that the antibody pro- ficiency occurs due to accelerated removal duce towards M. There is comple- It has been reported that the blood group anti- ment activation, which is followed by cell ly- gens, in some cases, are affected in certain dis- sis. The acquisition of B antigens in group destruction of platelets leading to sedormid A person has been reported. Damage ensues via complement-me- sera, the red cell suspension becomes agglu- diated lysis. This is known Drugs/metabolites, such as methyldopa as Thomsen-Friedenreich phenomenon. Microbiology: Principles and The correlation of blood group antigens Applications, 3rd edition. Immunoprophylaxis Vaccines 17 The purpose of immunization in one indi- vaccines, there remains the need to improve vidual is to prevent diseases. The objective the available vaccines as regard to safety and of immunization program has been respon- efficacy and cost-effectiveness, especially sible for spectacular advances in combating in developing country. Since 35% of infant deaths, in the world, are due 1977 smallpox has been eradicated, equal- to diseases that could be prevented by exist- ly encouraging is the predicted eradication ing vaccines. Therefore, stringent testing is The discipline of immunology had its roots in an absolute necessity, as the vaccines will be the early vaccination trials of Edward Jenner given to healthy subjects. In ac- Robert Koch was the pioneer to demon- tive immunization, the immunity is achieved strate the specific bacterial cause of anthrax naturally by suffering, clinically or subclini- (1876). Subsequently, the causes of several cally from the disease or by artificial means, common illnesses were rapidly identified. Similarly, in The control of number of the diseases passive immunization, the immunity is ob- that cause significant mortality has made out- tained naturally from mother to fetus by standing progress, but there remains an ur- transfer of antibody (from mother to infant gent need for vaccines against others. Every via milk or artificial injection of preformed year, millions are dying from malaria, tuber- antibody) (Table 17. Jenner and Pasteur are the stalwarts who pio- In addition to the challenges presented neered vaccines. So, also Emil von Behring by diseases for which there are no effective and Hidesaburo Kitasato are well recognized Immunoprophylaxis Vaccines 233 by their contributions to passive immunity. The recom- ferred passing from one individual to other mended program of childhood immuniza- by serum. Routine Immunization Active Immunization While introducing immunization schedule, The goal of the active immunization is to certain factors are taken into consideration. When active immunization is the infectious diseases, their public health successful, a subsequent exposure produce importance, availability of suitable vaccines, heightened response, leading to the elimina- the cost-benefit factors and the logistics. In tion of pathogen or prevention of the disease India, the Expanded Program on Immuniza- mediated by its products. The National Immunization Sched- active immunization, as the name implies, ule, in force, in India shown in Table 17. If a Viral particles vaccine induces only protective primary re- Hepatitis A Inactivated sponse and fails to induce memory cells, the Infuenza Inactivated host is not protected on subsequent infec- tion by the same microorganisms. The role of Measles Live attenuated memory cells also, is dependent on the incu- Polio (Sabin) Live attenuated bation period of the pathogen. For example, Polio (Salk) Inactivated in the case of influenza virus, which has a Rabies Inactivated short incubation period (1 or 2 day). The dis- ease symptoms are already on the way be- Rotavirus Live attenuated fore the memory cells are activated. Effective Rubella Live attenuated protection against influenza can be achieved Varicella zoster Live attenuated by repeated immunization to maintain a high (chickenpox) level of neutralizing antibody. An incuba- Toxoids tion period of this length gives the memory Diphtheria Inactivated exotoxin B cells more time to respond by producing high level of serum antibody. Tetanus Inactivated exotoxin In addition to the factors already men- Capsular poly- tioned, the effective protection against the saccharides Haemophilus Polysaccharideprotein intended pathogen must occur without dan- ger of causing disease or producing severe infuenzae type b carrier side effects. Besides, the vaccine must be Neisseria Polysaccharide economically feasible for production and be meningitidis suitably stable for storage, transport and use. Streptococcus 23 distinct capsular pneumoniae polysaccharides Whole Organism Vaccines Surface antigen Recombinant surface Many of the common vaccines, which are in antigen use fall into inactivated (killed) or live, but *There is also acellular pertussis vaccine. Attenuated vaccines may Attenuation can be achieved by growing a rarely, be associated with complications sim- pathogenic bacteria or virus for a prolonged ilar to those seen in natural diseases. Several examples, such as Sabin techniques to modify an animal rotavirus to polio, measles and other vaccines have been contain antigens present in human rotavirus. Killed Bacterial or Viral Vaccines Advantages: The attenuated vaccines have ad- vantages and disadvantages.
Each day buy kamagra 100 mg fast delivery, breath samples were taken and analyzed in the early morning on arrival at the laboratory order kamagra 50 mg without a prescription. For subject A kamagra 100mg visa, a 27-year-old female, the ammonia concentration in parts per billion (ppb) followed a normal distribution over 30 days with mean 491 and standard deviation 119. What is the probability that on a random day, the subject’s ammonia concentration is between 292 and 649 ppb? We find the z value corresponding to an x of 292 by 292 À 491 z ¼ ¼À1:67 119 σ = 119 292 491 649 x σ = 1 _1. To summarize, 292 À 491 649 À 491 P 292 x 649 P z 119 119 ¼ P À1:67 z 1:33 ¼ P À1 z 1:33 P À1 z À1:67 ¼ :9082 À :0475 ¼ :8607 The probability asked for in our original question, then, is. Solution: We first find the probability that one child selected at random from the population would be upright more than 8. Suppose we wish to find the cumulative probabilities for the following values of z : À3; À2; À1; 0; 1; 2; and 3. The preceding two sections focused extensively on the normal distribution, the most important and most frequently used continuous probability distribution. Though much of what will be covered in the next several chapters uses this distribution, it is not the only important continuous probability distribution. We will be introducing several other continuous distributions later in the text, namely the t-distribution, the chi-square distribution, and the F-distribution. The details of these distributions will be discussed in the chapters in which we need them for inferential tests. Output: Cumulative Distribution Function Normal with mean 0 and standard deviation 1. Find the probability that on a given day the subject’s acetone level is: (a) Between 600 and 1000 ppb (b) Over 900 ppb (c) Under 500 ppb (d) Between 900 and 1100 ppb 4. Suppose that the total ridge counts of individuals in a certain population are approximately normally distributed with a mean of 140 and a standard deviation of 50. According to data from the entire registry for 2001, the number of pounds gained during pregnancy was approximately normally distributed with a mean of 30. Calculate the probability that a randomly selected mother in North Carolina in 2001 gained: (a) Less than 15 pounds during pregnancy (b) More than 40 pounds (c) Between 14 and 40 pounds (d) Less than 10 pounds (e) Between 10 and 20 pounds 4. Ifitisreasonabletoassumeanapproximatelynormaldistributionoflengthsof stay, find the probability that a randomly selected patient from this group will have a length of stay: (a) Greater than 50 days (b) Less than 30 days (c) Between 30 and 60 days (d) Greater than 90 days 4. Find the probability that a subject selected at random from this population will weigh: (a) More than 155 pounds (b) 100 pounds or less (c) Between 105 and 145 pounds 4. The concepts of discrete and continuous random variables and their probability distributions are discussed. In particular, two discrete probability distributions, the binomial and the Poisson, and one continuous probability distribution, the normal, are examined in considerable detail. We have seen how these theoretical distributions allow us to make probability statements about certain random variables that are of interest to the health professional. Give an example of a random variable that you think follows a binomial distribution. Give an example of a random variable that you think is distributed according to the Poisson law. Give an example of a random variable that you think is, at least approximately, normally distributed. Using the data of your answer to Question 13, demonstrate the use of the standard normal distribution in answering probability questions related to the variable selected. Let p ¼ :35, and calculate the probability that: (a) Exactly seven of those drug events were preventable (b) More than half of those drug events were preventable (c) None of those drug events were preventable (d) Between three and six inclusive were preventable 16. In a poll conducted by the Pew Research Center in 2003 (A-13), a national sample of adults answered the following question, “All in all, do you strongly favor, favor, oppose, or strongly oppose. If 12 subjects represented by this sample are chosen at random, calculate the probability that: (a) Exactly two of the respondents answer “strongly favor” or “favor” (b) No more than two of the respondents answer “strongly favor” or “favor” (c) Between five and nine inclusive answer “strongly favor” or “favor” 17. On the average, two students per hour report for treatment to the first-aid room of a large elementary school. A Harris Interactive poll conducted in Fall, 2002 (A-15) via a national telephone survey of adults asked, “Do you think adults should be allowed to legally use marijuana for medical purposes if their doctor prescribes it, or do you think that marijuana should remain illegal even for medical purposes? Assuming 80 percent of Americans would say “Yes” to the above question, find the probability when eight Americans are chosen at random that: (a) Six or fewer said “Yes” (b) Seven or more said “Yes” (c) All eight said “Yes” (d) Fewer than four said “Yes” (e) Between four and seven inclusive said “Yes” 20. A nurse supervisor has found that staff nurses, on the average, complete a certain task in 10 minutes. If the times required to complete the task are approximately normally distributed with a standard deviation of 3 minutes, find: (a) The proportion of nurses completing the task in less than 4 minutes (b) The proportion of nurses requiring more than 5 minutes to complete the task (c) The probability that a nurse who has just been assigned the task will complete it within 3 minutes 23. Scores made on a certain aptitude test by nursing students are approximately normally distributed with a mean of 500 and a variance of 10,000. Given the normally distributed random variable X, find the numerical value of k such that P m À ks X m þ ks :754. Explain why each of the following measurements is or is not the result of a Bernoulli trial: (a) The gender of a newborn child (b) The classification of a hospital patient’s condition as stable, critical, fair, good, or poor (c) The weight in grams of a newborn child 34. Explain why each of the following measurements is or is not the result of a Bernoulli trial: (a) The number of surgical procedures performed in a hospital in a week (b) A hospital patient’s temperature in degrees Celsius (c) A hospital patient’s vital signs recorded as normal or not normal 35. Odum Institute for Research in Social Science at the University of North Carolina at Chapel Hill. All calculations were performed by John Holcomb and do not represent the findings of the Center or Institute. Pew Research Center survey conducted by Princeton Survey Research Associates, June 24–July 8, 2003. Time, Cable News Network survey conducted by Harris Associates, October 22–23, 2002. This chapter also includes a discussion of one of the most important theorems in statistics, the central limit theorem. Students may ﬁnd it helpful to revisit this chapter from time to time as they study the remaining chapters of the book. It is here that we encounter the concepts of central tendency and dispersion and learn how to compute their descriptive measures. In Chapter 3, we are introduced to the fundamental ideas of probability, and in Chapter 4 we consider the concept of a probability distribution. These concepts are fundamental to an understanding of statistical inference, the topic that comprises the major portion of this book. This chapter serves as a bridge between the preceding material, which is essentially descriptive in nature, and most of the remaining topics, which have been selected from the area of statistical inference. The importance of a clear understanding of sampling distributions cannot be overemphasized, as this concept is the very key to understanding statistical inference. Sampling distributions serve two purposes: (1) they allow us to answer probability questions about sample statistics, and (2) they provide the necessary theory for making statistical inference procedures valid. In this chapter we use sampling distributions to answer probability questions about sample statistics. We recall from Chapter 2 that a sample statistic is a descriptive measure, such as the mean, median, variance, or standard deviation, that is computed from the data of a sample.
There are limitations to this technique that include (a) differences (albeit slight) of the area from which the second P discount kamagra 100 mg on-line. In addition buy 100mg kamagra overnight delivery, the pacing artifact may obscure the early part of the captured local electrogram buy discount kamagra 100 mg online. In such instances, a comparable component of the electrogram can be used to measure the return cycle. Unfortunately sometime no electrogram is seen at the St-N + 1 interval, suggesting that pacing was capturing far field tissue. The return cycle, which is equal to the tachycardia cycle length, confirms that the recorded electrogram is within the reentrant circuit. Although the proposed methods of identifying components of a reentrant circuit is useful, focal ablation of all sites defined as in the reentrant circuit may not result in a cure of the tachycardia. Cure of the tachycardia requires ablation of an isthmus bordered by barriers on either side. Because the reentrant circuit incorporates sites outside this critical isthmus, ablation of these “external” sites will not result in cure of the tachycardia, although it may alter either the cycle length or the morphology slightly. The ideal map should therefore be one in which the recorded electrogram comes from within or incorporates the protected isthmus through which the impulses must circulate. If the three criteria proposed above are met, the electrogram most likely is recorded from this zone. We have shown that use of these criteria identifies successful and unsuccessful ablation sites with high predictive 148 44 51 308 accuracy. Proof of localization within this isthmus would require alteration of the tachycardia cycle length and termination by a perturbation at that site. If this could be done by the delivery of subthreshold 354 stimuli, as suggested by Shenasa et al. Similarly, termination by transient application of cryothermia would suggest an isthmus location. There are many limitations to accomplishing all of these components of mapping, not the least of which is patient tolerance. Nevertheless, if one could fulfill all these mapping criteria, one should identify the critical zone of the reentrant pathway, which, if ablated, should cure the arrhythmia. Limitations of catheter position and recording electrodes as well as the inability to predict the amount of current delivered to the reentrant pathway may obviously result in responses that would not meet all the requirements of the ideal ablation site. As noted earlier in this chapter, patients with either dilated or hypertrophic cardiomyopathy demonstrate reasonably normal endocardial electrograms and activation patterns 32 73 (Figs. The vast majority of tachycardias associated with coronary artery disease and prior infarction arise from the left ventricular endocardial or subendocardial areas. Because the bipolar electrogram records endocardial and subendocardial activity, the electrograms can be normal if the tachycardia has an intramural or epicardial origin (see earlier discussion). Using this technique they have demonstrated early activation on the epicardium in patients with Chagas disease and in highly selected patients with inferior infarction, which they targeted for ablation. While epicardial mapping and ablation via the pericardium may be useful in selective cases, there are special factors that must be considered. Significant epicardial fat may lead to inaccurate activation times and reduction of bipolar voltage due to the recording of far field signals. Radiofrequency ablation in the pericardial space is less effective, given poor contact force, the lack of electrode cooling because of absent blood flow (although “cool tip” catheters can be used), and the presence of insulating 403 epicardial fat. In addition, the possibility of damage to the immediately contiguous epicardial coronary arteries, the left phrenic nerve, and the lungs need to be appreciated and avoided. Nonsurgical transthoracic epicardial catheter ablation to treat recurrent ventricular tachycardia occurring late after myocardial infarction. The inferobasal portion of the right ventricle which uses the tricuspid annulus as a fixed barrier is the most common site of an isthmus, while the apical free wall is the least common. The extent of the disease is paralleled by the extent of abnormalities of electrograms in sinus rhythm (see following section entitled Sinus Rhythm Mapping). In such cases, the scar in the right ventricular outflow tract appears to provide at least one potential 157 160 barrier around which the impulse may circulate. For various reasons discussed earlier in this chapter, I do not believe the fascicles have been proven to be part of the reentrant circuit. These tachycardias frequently demonstrate 345 diastolic potentials on the septum leading to a zone of slow conduction, but such potentials have not been universally found. The widely separate potentials are recorded from opposite sides of the ventriculotomy scar. Electrophysiologic characteristics of sustained ventricular tachycardia occurring after repair of tetralogy of Fallot. The mode of initiation, response to stimulation, and effect of drugs on such tachycardias will also provide indirect evidence for the type of mechanism for the arrhythmia. Of importance, however, is the recognition that because tachycardias in cardiomyopathy may be midmyocardial or even subepicardial, the earliest site of activation on the endocardium P. This is important because most standard radiofrequency catheter ablation techniques result in a lesion <2 to 5 mm in depth and could therefore fail to ablate a tachycardia that is subepicardial. Epicardial mapping or use of newer technologies may be necessary to define critical sites for ablation in patients with nonreentrant mechanisms and/or cardiomyopathies in whom intramural or subepicardial sites are critical. The ablation catheter is recording from sites A, B, and C on the schema at the top with recordings shown in the panels on the bottom. This occurs because many potential channels can go through the scar leading to many different tachycardia circuits. In the remaining 15% of 368 369 370 tachycardias, reentrant circuits and/or exit sites are more disparate. In the presence of coronary artery disease, the vast majority of all tachycardias, regardless of morphology, arise in or near the subendocardial surface of the left ventricle. C: A tachycardia with a right bundle branch block, right inferior axis pattern is seen. This site is 2 cm above site 3 and forms the 2 apex of a triangle between three sites, which cover an area of approximately 3. Although individual tachycardia morphologies can be initiated at different times, not infrequently one tachycardia changes to another in response to programmed stimulation (Fig. In such cases, we believe that stimulation either causes a change in location or direction of activation from the site of exit from the reentrant circuit or a change in the activation sequence in the ventricular tissue surrounding the exit site by altering the electrophysiologic properties of this tissue. Occasionally, the change in configuration is abrupt, suggesting a change in exit pattern (Fig. In either of the latter two instances, because the reentrant circuit is unaffected, the tachycardia cycle length is unaffected as well. Thus, change in tachycardia morphology need not reflect a change in a reentrant circuit or site of impulse formation but merely reflects the overall pattern of ventricular activation. The cycle length may also be altered because the conduction velocity through nonuniform anisotropic tissue can change based on the direction of the 404 propagating wavefront. Changes in cycle length, sites of origin, or direction of the propagating wavefront can result in failure to propagate to or through other areas of the ventricle that are not necessary for the maintenance of the tachycardia.
That is generic 100mg kamagra free shipping, in a population of asymptomatic patients purchase kamagra 100mg mastercard, a short refractory period of the bypass tract kamagra 50mg lowest price, a shortest R-R interval <220 msec or a mean ventricular response of <250 msec during atrial fibrillation does not actually identify a patient who is likely to be at high risk for the development of sudden death, particularly when achieved with isoproterenol. The demonstration that patients who have ventricular fibrillation have short refractory periods does not mean that all patients who have short refractory periods will develop ventricular fibrillation. The degree of overlap obviously indicates that the predictive value of a short refractory 64 period for the development of cardiac arrest would be low. No sudden cardiac death occurred in asymptomatic patients, and only two symptomatic patients died suddenly, one of whom was an athlete with a grossly enlarged and hypertrophied heart (520 g) at autopsy. He divided the patients into 52 with effective refractory periods ≤240 msec and 90 patients with effective refractory periods >240 msec and followed them for more than 20 years. Only two patients in both groups died suddenly, and in only one patient in each group did atrial fibrillation seem a likely cause. Thus, the overwhelming evidence suggests that one cannot use the antegrade effective refractory period measurements to predict patients at risk for development of sudden death. It also does not appear that the use of the ventricular response during induced atrial fibrillation, particularly in asymptomatic patients, is useful. It is my personal bias that regardless of the presence or absence of symptoms, these measurements are poor predictors of patients at risk. Patients with syncope do not have distinct clinical or electrophysiologic features that differ from P. Thus, I believe that we cannot predict patients at high risk for sudden death but we are able to select patients at low risk for sudden death. This is useful because it has implications for lifestyle recommendation for these patients. The widespread use of electrophysiologic studies to predict patients who are likely to die, and therefore have limitations placed on their life-style, seems totally unjustified at this point. The only things we can do are (a) assure people who are totally asymptomatic that they are unlikely to experience sudden cardiac death and, if less than 30 years old, are likely to remain asymptomatic regardless of their effective refractory periods and (b) reassure those patients who have prolonged refractory periods as assessed by any method that they are extremely unlikely to develop ventricular fibrillation regardless of whether symptoms are present or not. Finally, one must remember that freedom from developing life- threatening ventricular response during atrial fibrillation or the demonstration of a long antegrade refractory period of the bypass tract is of no value in predicting the likelihood of developing orthodromic tachycardia. A: A single atrial stimulus terminates the tachycardia by blocking in the A-V node. The tachycardia is terminated when the early atrial impulse attempts to return to the ventricle but blocks antegradely in the A-V node. Termination of Orthodromic Tachycardia Because the reentrant circuit in orthodromic tachycardia is large and incorporates both the atrium and ventricles, premature stimuli from either chamber can almost always penetrate the circuit, even during tachycardias with rapid rates. More rapid rates may necessitate the introduction of multiple electrical stimuli to reach either the normal A-V conducting system or the bypass tract during its refractory state. Thus, in most tachycardias with cycle lengths exceeding 300 msec, single atrial and/or ventricular extrastimuli can terminate the arrhythmia (Fig. The faster the rate, and the farther the extrastimulus is from the site of the bypass tract, the more premature or the greater the number of stimuli required to terminate the arrhythmia. Thus, in patients with right-sided or septal bypass tracts, single premature stimuli from the right atrium or the right ventricle will almost always terminate tachycardias with cycle lengths >300 msec. Ventricular extrastimuli then can result in termination of the tachycardia even when delivered when the His bundle is refractory (Fig. The response to ventricular extrastimuli, however, can vary greatly, depending on the coupling interval and number of ventricular extrastimuli needed. Thus, ventricular extrastimuli can terminate the tachycardia by (a) blocking retrogradely in the bypass tract; (b) conducting retrogradely up the normal A-V conducting system, with or without retrograde conduction up the bypass tract; or (c) retrograde conduction over the bypass tract with subsequent antegrade block in the A-V node, or occasionally below the His bundle (Fig. A–C demonstrate orthodromic circus movement tachycardia using a left-sided bypass tract, each of which is terminated by ventricular extrastimuli. A: The first of three ventricular extrastimuli blocks retrogradely in the bypass tract and collides with the impulse in the normal His–Purkinje system. The third extrastimulus blocks retrogradely in both the bypass tract and the His–Purkinje system. B: The first extrastimulus, which is delivered when the His bundle is refractory, blocks in the bypass tract. The third extrastimulus blocks in the bypass tract and conducts retrogradely up the normal A-V conducting system to depolarize the atrium and terminate the tachycardia. C: The first extrastimulus is delivered while the His bundle is refractory and preexcites the atrium. The second extrastimulus blocks in the bypass tract, conducts up the His– Purkinje system, blocks in the node, and terminates the tachycardia. Multiple Bypass Tracts Because A-V bypass tracts appear to be a congenital abnormality that is due to developmental defects in the A-V rings, it is not surprising that multiple A-V bypass tracts can be present in the same patient. In the preablation era we recognized nearly one-third of the bypass tracts, unsuspected during the preoperative electrophysiology study, at the time of surgery. The wide range of incidence in multiple bypass tracts probably stems from differences in patient populations and methodologic differences in determining the presence of such bypass tracts. The observation of changing antegrade delta waves – that is, changing patterns of preexcitation – is uncommon during sinus rhythm. Occasionally, following the use of Type I agents or amiodarone, block in one accessory pathway can lead to manifestation of antegrade conduction over a second 38 accessory pathway. Atrial fibrillation (either spontaneous or induced) may provide the opportunity to see different patterns of preexcitation, thereby allowing one to document the presence of multiple bypass tracts. This has been suggested as an indication for the deliberate induction of atrial fibrillation during an electrophysiologic study. Because multiple bypass tracts are often located in the free walls of the right and left A-V grooves, the use of both right and left atrial pacing occasionally can document the presence of additional bypass tracts that are not manifested if only pacing from the one atrium is performed. This can be seen in Figure 10-95, where right atrial pacing produces ventricular activation over a right-sided bypass tract, and coronary sinus pacing produces ventricular activation over a left-sided bypass tract. In addition, the tachycardias initiated by stimulation at different sites can vary, resulting in two retrograde activation sequences, which document the presence of multiple bypass tracts (see following discussion). If a single bypass tract was present, the V-A interval should be fixed and the retrograde P-wave morphology constant during orthodromic tachycardia. If the V-A interval or P- wave morphology changes during orthodromic tachycardia, the presence of an additional bypass tract should be suspected. During the electrophysiology study, the presence of two distinct retrograde atrial activation patterns documents the presence of multiple bypass tracts and explains changing P-wave morphology and V-A intervals (see Fig. In other cases, during orthodromic tachycardia, a single, fixed retrograde atrial activation pattern is observed in the presence of two or more bypass P. In this instance, additional bypass tracts can be recognized by the appearance of more than one atrial breakthrough site. This is demonstrated in Figure 10-96, where the earliest retrograde atrial activation occurs in the distal coronary sinus, compatible with a left lateral bypass tract.
The patient who expects this course of treatment will be better prepared to persist over time so that results can be achieved and maintained long term order kamagra 50 mg online. Little research has examined the durability of behavioral treatments in the long term cheap kamagra 100mg online, but studies are promising in that many patients are able to sustain improvements in bladder control over time [72–74] kamagra 50 mg low price. Most patients who engage actively with behavioral treatment for incontinence experience some degree of improvement, yet there is considerable variation in outcomes. Little is known to help us predict which patients will respond best to behavioral treatment. Most studies examining predictors of success have found that outcomes are not related to the type of incontinence or urodynamic diagnosis [13,52,55,75,76]. Some studies show that patients with more severe incontinence have greater improvements [52,72], but others conclude that patients with more severe incontinence have poorer outcomes [22,72,76] or no relationship between severity and outcome [24,55,75,77]. Current evidence indicates that outcomes are not associated with patient race, parity, body mass index, cystocele, uterine prolapse, hysterectomy, hormone therapy, use of diuretics, or urodynamic parameters . There is little information in the usual clinical evaluation of a patient with incontinence that would indicate the likelihood of her success or failure with behavioral treatment. Thus, given that behavioral therapies are virtually without risk and most adherent patients experience symptom improvement, offering behavioral treatment as first-line therapy is appropriate for any woman with urinary incontinence. Moore K, Dumoulin C, Bradley C, Burgio K, Chambers T, Hagen S, Hunter K, Imamura M, Thakar R, Williams K. 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Pelvic floor muscle training is effective in treatment of female stress urinary incontinence, but how does it work? Adherence to behavioral interventions for urge incontinence when combined with drug therapy: Adherence rates, barriers, and predictors. Adherence to behavioral interventions for stress incontinence: Rates, barriers, and predictors. Pelvic floor muscle exercise for the treatment of stress urinary incontinence: An exercise physiology perspective. Pelvic floor muscle training versus no treatment, or inactive control treatments, for urinary incontinence in women. Systematic review: Randomized, controlled trials of nonsurgical treatments for urinary incontinence in women. Comparisons of approaches to pelvic floor muscle training for urinary incontinence in women. An assessment of the Frewen regime in the treatment of detrusor dysfunction in females. A controlled trial of bladder drill and drug therapy in the management of detrusor instability. The management of urinary incontinence due to primary vesical sensory urgency by bladder drill. Assessment and treatment of female urinary incontinence by cystometrogram and bladder retraining programs. Oxybutynin and bladder training in the management of female urinary urge incontinence: A randomized study. Comparative efficacy of behavioral interventions in the management of female urinary incontinence. Reliability assessment of the bladder diary for urinary incontinence in older women. Dietary caffeine intake and the risk for detrusor instability: a case-control study. Prevalence of urinary incontinence and associated risk factors in postmenopausal women. Obesity and lower urinary tract function in women: Effect of surgically induced weight loss. Gynecologic-obstetric changes after loss of massive excess weight following bariatric surgery. Changes in urinary and fecal incontinence symptoms with weight loss surgery in morbidly obese women. Long-term efficacy of nonsurgical urinary incontinence treatment in elderly women. Long-term effect of pelvic floor muscle exercise 5 years after cessation of organized training. The effect of behavioral therapy on urinary incontinence: A randomized controlled trial. Predictors of outcome in the behavioral treatment of urinary incontinence in women.
External vibrations close to these natural frequencies will result in amplifcation of vibration purchase kamagra 50 mg mastercard. Typical body resonant frequencies are: Shoulder girdle 4–5 Hz Abdominal organs 4–8 Hz Head 5–6 Hz Facial tissues 15–20 Hz 2 Pathophysiology of Flight 21 Eyes 60–90 Hz Whole body (vertical plane) 2–10 Hz Whole body (horizontal plane) less than 3 Hz Flight can increase exposure to vibration [3 order 50mg kamagra mastercard, 4] buy 50 mg kamagra with visa. This can be from sources within the aircraft, such as the engine, or external to the aircraft, such as turbulent air. In a rotary-wing aircraft, vibration occurs in all axes of movement and is generally worse in the transition stages to hover. Rotating components and gears are the main sources of vibration in rotary-wing aircraft, whereas engine operation, propellers, and turbulence are the principal sources related to fxed-wing aircraft. These include generalised discomfort and fatigue from muscle contractions in an attempt to dampen the vibration and low back pain especially for those in a seated position. There can be impairment of capacity to undertake precise manual tasks by vibration at frequencies of ~4–6 Hz and blurring of vision can occur at frequencies of 2–20 Hz. Speech can be distorted at frequencies of 4–12 Hz and prolonged exposure to vibration can impair the ability to undertake complex cognitive tasks. These effects can be particu- larly signifcant for retrieval teams that work constantly within the aeromedical environment and can be a signifcant contributor to fatigue, impairment of the abil- ity to perform complex cognitive tasks, and subsequent human error. In patients with haemorrhage, such as those with major pelvic trauma, vibrations may potentially destabilise clots and facilitate increased bleeding . Some clini- cians believe that vibration may impact adversely the cardiovascular and respiratory systems. There is also a theoretical risk of increased bubble formation in patients with decompression illness. Tribonucleation is a physical process where gas bubbles can be formed at an interface where two adherent surfaces are rapidly pulled apart. Vibration appears to accelerate this process, although its impact in vivo is not known . Indeed, the overall risks to a patient in relation to vibration are not well understood and the complex characteristics of vibration in the aeromedical environment make it very diffcult to conduct meaningful research in this area. However, it is still important to remain alert to the actual and potential effects of vibration on both aircrew and patients and to attempt to reduce those effects where possible. This is primarily an engineering issue relating to areas such as stretcher design, restraint systems, damping mechanisms, and overall aircraft maintenance. Finally, be aware that vibration can also impact medical equipment either by affecting its function, such as with non- invasive oscillometric blood pressure monitors and activity-sensing pacemakers, or by leading to dislodgement, such as the migration of an endotracheal tube. Ramin Hypoxia Thermal stress Noise Vibration Dehydration Physical activity Increased workload Motion sickness Fatigue, in turn, leads to a lack of motivation, impaired short-term memory, increased reaction time, impaired judgement, intolerance, frustration, risk-tak- ing behaviour, and poor decision-making. None of these traits are helpful in the conduct of a complex medical repatriation. The pathophysiology is complex and not fully understood, but it is essentially the result of a confict of sensory inputs between what your eyes see, what your vestibular apparatus senses, and what signals your brain expects as opposed to those it actually receives. The motion associated with fight can com- monly lead to motion sickness, particularly in turbulent conditions, as your inability to fully visualise the outside world whilst the aircraft is moving can lead to such a vestibular-visual confict. The most important thing to remember in regard to motion sickness is that it can affect anyone at any time, including aircrew who have fown extensively with no prior problems. Pregnant individuals, children, people with prior or current vestibular disease, migraine sufferers, and those who exhibit marked anxiety about the potential for motion sickness appear are at increased risk. General malaise, sweating, nausea, vomiting, and an exaggerated sense of motion are typical features. This can not only be unpleasant, but if occurring in the aircrew can also signifcantly compro- mise their ability to carry out their essential functions. It is important to understand the implications of these on normal human physiology and what steps can be taken to minimise the potential for related adverse clinical conse- quences in sick or injured patients being transported by air. It is equally important to remember that these physiological changes and environmental stressors can impact the aircrew and medical equipment. Finally, it is worth noting that whilst the potential implications of these changes are generally well understood, their actual 2 Pathophysiology of Flight 23 clinical signifcance is not. For example, Boyle’s law clearly predicts that a pneu- mothorax will expand at altitude, but does that mean that there is a risk of clinical deterioration or even tension when we fy such a patient, and if so, is it likely also dependent on other factors such as the aetiology of the pneumothorax, duration of fight, and associated comorbidities? Unfortunately, the relatively isolated and potentially hostile nature of the aeromedical environment is a diffcult one in which to establish high-quality clinical trials and most such questions have not been, and indeed may never be, answered by research. Critical care air transport: patient fight physiology and organizational consider- ations. Aerospace Medical Association, Aviation Safety Committee, Civil Aviation Subcommittee. Cleared for takeoff: the effects of hypobaric conditions on traumatic pneumothoraces. Leg edema formation and venous blood fow velocity during a simulated long-haul fight. Interfacility transport of patients with decompression illness: literature review and consensus statement. Effects of hot and cold temperature exposure on performance: a meta-analytic review. Effects of health care provider work hours and sleep deprivation on safety and performance. Those issues primarily concern what and whose law governs the situation, and the resulting liability implications and protec- tions for physicians and other healthcare providers. The frst section addresses the Aviation Medical Assistance Act and the parameters it sets forth for protecting air carriers and healthcare providers. This section also addresses how healthcare pro- vider liability might be addressed under the Act, depending upon the state in which a claim is pursued. International carrier liability is briefy discussed, but given the fact that there is no uniform liability standard, it is diffcult to predict how such actions may resolve. In-fight medical encounters are addressed in the next section, which concludes that there is insuffcient data compiled by the government and carriers to effectively analyze it, but there is enough to know that there are tens of thousands of medical incidents each year, making it a real possibility that a healthcare provider could be confronted with such an event during commercial air travel. Lastly, the chapter addresses important considerations before giving care, such as there is no actual legal requirement to begin giving medical care during a commercial fight, but if care is begun, the provider must satisfy general requirements as detailed below. Congressional reports produced during this inquiry observed that “the most commonly observed serious in-fight medical events are cardiac in nature, with ventricular fbrillation being the most common form of abnormal heart rhythm” . The Act also addresses requirements that major air carriers report certain details of deaths that occur on their fights or as a result of in-fight incidents . Those regulations currently state that all fights for which a fight attendant is required must contain at least one approved emergency medical kit (see Table 1. This directive translates to aircraft with a capacity of approxi- mately 30 passengers. The fnal substantive section of the Act creates two different limitations on liability. First, for the airline, the Act imposes a very high barrier to liability for its role in seek- ing to obtain assistance from passengers to address an in-fight medical emergency: An air carrier shall not be liable for damages in any action brought in a Federal or State court arising out of the performance of the air carrier in obtaining or attempting to obtain the assistance of a passenger in an in-fight medical emergency, or out of the acts or omis- sions of the passenger rendering the assistance, if the passenger is not an employee or agent of the carrier and the carrier in good faith believes that the passenger is a medically quali- fed individual . As long as the passenger is not an employee or agent of the airline and the airline has a good faith belief that the passenger is a “medically qualifed individual,” which is defned as “any person who is licensed, certifed, or otherwise qualifed to provide medical care in a State, including a physician, nurse, physician assistant, paramedic, and emergency medical technician” , the airline is completely immune from lia- bility related to passengers who assist during an in-fight emergency. This subsection does not explicitly state that it protects only individuals aboard “air carriers,” i.
However order 100 mg kamagra with mastercard, a vertical complications generic 50 mg kamagra amex, such as wound dehiscence discount kamagra 50 mg fast delivery, seroma, hema- scar can still be performed for these patients in speciﬁc toma, and a high rate of secondary revision. There have been cases, such as patients who have dark skin or a history of attempts to decrease these complications by using limited hypertrophic scarring. An inverted-T scar is more suitable skin undermining and adding short horizontal scars. Vertical for patients who have poor skin elasticity associated with excision techniques must involve more than a vertical pattern striae. Despite the fact that we are very keen on using vertical and any other short-scar techniques in breast 7 Complications reduction, breast shaping and modeling are most important to patients. We with the vertical reduction, until we started thromboembolic still prefer a vertical scar to close the breast in young patients prophylaxis and tumescent inﬁltration. This led to an unac- or those with dark skin, even with the potential for second- ceptable rate of hematomas, some of which had to be surgi- ary scar correction, because this will result in more a limited cally revised. Currently, we do not use any thromboembolic scar, rather than ending up with an inverted-T scar performed prophylaxis unless strictly indicated by hematologists, and immediately at the end of surgery. Based on a well- we inﬁltrate the breast avoiding the tumescent-type inﬁltra- vascularized and constant anatomical structure, the pedicle tion, which obviously can lead to spasm some perforating is safer, especially in the event of major breast hypertrophy. In our experience, the septum-based mammaplasty tech- Big seromas are very rare in our experience, even with the nique shows advantages over conventional techniques of use of drains, which we leave for a week. Small seromas are breast reduction in terms of pedicle shaping, breast remodel- probably more common, but they usually do not necessitate ing, and maintaining nipple-areola complex sensation. The key point of this technique is reduction of the infero- Nipple-areola partial or total necrosis is a feared event, lateral and central parts of the breast and preservation of the although it is very rare, which luckily we have never had. In the authors’ experience, a use the medial (lateral) pedicle for most of our gigantomas- lateral pedicle offers good projection and maintains nipple- tias, thus limiting the use of a pure superior pedicle to the areola complex sensitivity. In case of clear engorgement, many authors sug- A medial pedicle is chosen in cases of extreme breast gest to remove some skin suture, although there is no clear hypertrophy with signiﬁcant lateral fullness. This event would probably beneﬁt only Vertical Breast Reduction 237 from immediate reoperation, but this is clearly impossible as it would be too traumatic for the patient. Pearls and Pitfalls On the other side, an intraoperative venous stasis can be Vertical breast reduction is not a technique for every obviously treated by modifying the position of the pedicle patient! We routinely use antibiotics after this type of operation, and we do think that a constricting vertical/gathering closure • Avoid skin undermining. However, liponecrosis can be a problem, because of late calciﬁcations, delayed healing, and long-term asymmetries. In documented cases of large liponecrosis, sur- References gical removal and breast remodeling are appropriate. Plast Reconstr Surg 101:1486–1493 Shape deformities are more common, and we consider 4. Plast Reconstr Surg 49:245–252 Puckers, underresection, and inframammary fold unadher- 5. For this The vertical mammaplasty: a reappraisal of the technique and its complications. Plast Reconstr Surg 111:2192–2202 reason, we carefully inform patients of this possibility that 6. Plast Reconstr An extremely long vertical scar is, to our opinion, the Surg 104:2289–2298; (Discussion) 2299–2304 8. Lejour M (1994) Vertical mammaplasty and liposuction of the result of an inappropriate surgical planning. Plast Reconstr Surg 115:1179–1197 As in every plastic surgery operation, informed consent is 12. Plast Reconstr Surg 123:443–454 peculiarities that must be well understood by the patient. In: Nahai F (ed) operation is designed to give a long-lasting result with the The art of aesthetic surgery. Quality beneﬁt of eliminating the horizontal scar, which is truly a Medical Publishing, St. Marchac D, de Olarte G (1982) Reduction mammaplasty and cor- rection of ptosis with a short inframammary scar. This includes a transient boxy shape, Surg 69:45–55 late healing in the vertical scar, and the presence of puckers. Skoog T (1963) A technique of breast reduction; transposition of Although this generally settles up with time and rarely the nipple on a cutaneous vascular pedicle. Gigantomastia Francesco Moschella , Adriana Cordova , and Francesca Toia The idea of beauty and “normality” of the breast has undergone Macromastia or mammary hypertrophy is a deforming, many changes over the years, depending upon customs and disabling, and painful condition characterized by an enlarge- society. To date, breasts are considered normal when symmet- ment of various degrees of one or both breasts. Besides being ric, with a volume ranging between 250 and 400 ml and the a signiﬁcant aesthetic defect, this condition causes physical nipple-areola complex situated above the inframammary fold. Morphologic differences exist between races, which also Clinical manifestations associated to mammary hypertro- depend on weight, age, height, and thoracic structure of the phy are: patient. Therefore, it is rather hard to establish universal ana- tomic and clinical criteria to mark a clear-cut limit between • Intertriginous lesions induced by friction of the breast normality and hypertrophy of the mammary glands. In to infections by Candida, further increasing irritation of this regard, clinically important features are: reddened areas. In one of the most accepted classiﬁcations, considering standard breast volume as ranging between 250 and 400 ml, An ulnar neuropathy has also been described in women hypertrophy is deﬁned as mild for volumes between 400 and with severe breast hypertrophy, who report paresthesia in the 600 ml, moderate between 600 and 800 ml, severe between ulnar nerve territory. Moreover, psychological problems can negatively inﬂu- A distance of 16–21 cm between the midclavicular point ence social and sexual life. Reduction mammaplasty has to and the nipple-areola complex is considered “normal,” but be considered, in such a clinical picture, the best therapeutic this value is considerably inﬂuenced by patient height. Sezione di Chirurgia Plastica e Ricostruttiva, Dipartimento di Discipline Chirurgiche e Oncologiche, Università di Palermo, The mammary gland, being derived from the ectoderm, is Palermo , Italy contained in the superﬁcial layer of the subcutaneous tissue, © Springer Berlin Heidelberg 2016 239 N. It is anchored to A horizontal ﬁbrous septum originates from the pectoral fascia the pectoralis major fascia by the suspensory ligaments ﬁrst along the level of the ﬁfth rib, dividing the mammary gland in described by Cooper in 1840, which run from the deep fascia a cranial and a caudal part. It acts as a suspensory system and throughout the parenchyma to attach to the dermis of the skin. Their superﬁcial branches anasto- • An increase in free estrogen circulating levels, due to mose in the subdermal plexus, supplying the breast skin. Perforators from the third to sixth inter- space also present a superﬁcial course and supply a medially Hyperprolactinemia has been associated with mammary based pedicle. The lateral pedicle relies on the lateral tho- hypertrophy, but its exact role is not absolutely clear. Not all racic system that is usually found 2 or 3 cm deep to the skin patients with hyperprolactinemia present with breast hyper- at the level of the inframammary fold. The sensory innervation of the breast is mainly derived from Another reported association is between hypercalcemia the anterolateral and anteromedial branches of thoracic inter- and juvenile and pregnancy-induced hypertrophy, which has costal nerves T3–T5. The anterior branch of the lism, one case of macromastia in an infant with Alagille’s third intercostal nerve also contributes to the sensitivity of syndrome has been reported in literature, in which mam- the nipple-areola complex; it takes a superﬁcial course within mary hypertrophy was directly correlated to alterations in the subcutaneous tissue and terminates at the medial areolar the hepatic metabolism of estrogens, rather than to their border .
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