By G. Emet. College of Notre Dame of Maryland.
The cases may be cross-classified by “bow-tie sign” status and surgical results as follows: Tear Surgically Tear Surgically Confirmed As Confirmed (D) Not Present ðÞD Total Positive Test 38 10 48 (absent bow-tie sign) (T) Negative Test (bow-tie sign present) ðÞT Total 43 28 71 Source: Theodore A buy oxytrol online pills. They cited a study by Brusilow and Horwich (A-8) that estimated the sensitivity of the allopurinol test as generic oxytrol 2.5 mg otc. Use this information and Bayes’s theorem to calculate the predictive value negative of the allopurinol screening test cheap oxytrol 5 mg with mastercard. The objective has been to provide enough of a “feel” for the subject so that the probabilistic aspects of statistical inference can be more readily understood and appreciated when this topic is presented later generic 2.5 mg oxytrol free shipping. We defined probability as a number between 0 and 1 that measures the likelihood of the occurrence of some event. Objective probability can be categorized further as classical or relative frequency probability. After stating the three properties of probability, we defined and illustrated the calculation of the following kinds of probabilities: marginal, joint, and conditional. We also learned how to apply the addition and multiplication rules to find certain probabilities. We learned the meaning of independent, mutually exclusive, and complementary events. We learned the meaning of specificity, sensitivity, predictive value positive, and predictive value negative as applied to a screening test or disease symptom. Finally, we learned how to use Bayes’s theorem to calculate the probability that a subject has a disease, given that the subject has a positive screening test result (or has the symptom of interest). Define the following: (a) Probability (b) Objective probability (c) Subjective probability (d) Classical probability (e) The relative frequency concept of probability (f) Mutually exclusive events (g) Independence (h) Marginal probability (i) Joint probability (j) Conditional probability (k) The addition rule (l) The multiplication rule (m) Complementary events (n) False positive (o) False negative (p) Sensitivity (q) Specificity (r) Predictive value positive (s) Predictive value negative (t) Bayes’s theorem 2. The study used data from the Behavioral Risk Factor Surveillance System surveys of adults age 18 years or older conducted in 1999 and 2000. The table below reports the number of observations of Hispanic and non-Hispanic women who had received a mammogram in the past 2 years cross-classified with marital status. Wilson, “Breast and Cervical Cancer Screening Practices Among Hispanic and Non-Hispanic Women Residing Near the United States–Mexico Border, 1999–2000,” Family and Community Health, 26 (2003), 130–139. The table below shows the skill retention numbers in regard to overall competence as assessed by video ratings done by two video evaluators. The researchers classified subjects into four personality types: obsessiod, asthenic=low self-confident, asthenic=high self-confident, nervous=tense, and undeterminable. A certain county health department has received 25 applications for an opening that exists for a public health nurse. If a selection from among these 25 applicants is made at random, what is the probability that a person over 30 or a person with a master’s degree will be selected? Made a low score on the examination given that he or she graduated from a superior high school. For a variety of reasons, self-reported disease outcomes are frequently used without verification in epidemiologic research. They used the self-reported cancer data from a California Teachers Study and validated the cancer cases by using the California Cancer Registry data. The following table reports their findings for breast cancer: Cancer Reported (A) Cancer in Registry (B) Cancer Not in Registry Total Yes 2991 2244 5235 No 112 115849 115961 Total 3103 118093 121196 Source: Arti Parikh-Patel, Mark Allen, William E. Wright, and the California Teachers Study Steering Committee, “Validation of Self-reported Cancers in the California Teachers Study,” American Journal of Epidemiology, 157 (2003), 539–545. In a certain population the probability that a randomly selected subject will have been exposed to a certain allergen and experience a reaction to the allergen is. If a subject is selected at random from this population, what is the probability that he or she will have been exposed to the allergen? Suppose that 3 percent of the people in a population of adults have attempted suicide. It is also known that 20 percent of the population are living below the poverty level. In a certain population of women 4 percent have had breast cancer, 20 percent are smokers, and 3 percent are smokers and have had breast cancer. The probability that a person selected at random from a population will exhibit the classic symptom of a certain disease is. For a certain population we define the following events for mother’s age at time of giving birth: A ¼ under 20 years; B ¼ 20–24 years; C ¼ 25–29 years; D ¼ 30–44 years. For a certain population we define the following events with respect to plasma lipoprotein levels (mg=dl): A ¼ (10–15); B ¼ð! State in words the meaning of the following events: (a) A [ B (b) A B (c) A C (d) A [ C 20. Since they show all possible values of a random variable and the probabilities associated with these values, probability distributions may be summarized in ways that enable researchers to easily make objective deci- sions based on samples drawn from the populations that the distributions represent. This chapter introduces frequently used discrete and continuous probability distributions that are used in later chapters to make statistical inferences. We build on these concepts in the present chapter and explore ways of calculating the probability of an event under somewhat more complex conditions. In this chapter we shall see that the relationship between the values of a random variable and the probabilities of their occurrence may be summarized by means of a device called a probability distribution. A probability distribution may be expressed in the form of a table, graph, or formula. Knowledge of the probability distribution of a random variable provides the clinician and researcher with a powerful tool for summarizing and describing a set of data and for reaching conclusions about a population of data on the basis of a sample of data drawn from the population. The purpose of the study was to examine hunger rates of families with children in a local Head Start program in Athens, Ohio. In addition, participants were asked how many food assistance programs they had used in the last 12 months. We wish to construct the probability distribution of the discrete variable X, where X ¼ number of food assistance programs used by the study subjects. We compute the probabilities for these values by dividing their respective frequencies by the total, 297. These are not phenomena peculiar to this particular example, but are characteristics of all probability distributions of discrete variables. With its probability distribution available to us, we can make probability statements regarding the random variable X. Solution: To answer this question, we use the addition rule for mutually exclusive events. The cumulative probability distribution for the discrete variable whose probability distribution is given in Table 4. The length of each vertical line represents the same probability as that of the corresponding line in Figure 4. Solution: Since a family that used fewer than four programs used either one, two, or three programs, the answer is the cumulative probability for 3. Solution: To find the answer we make use of the concept of complementary probabili- ties. The set of families that used five or more programs is the complement of the set of families that used fewer than five (that is, four or fewer) programs. In later sections, we study in detail three of these theoretical probability distributions: the binomial, the Poisson, and the normal. Mean and Variance of Discrete Probability Distributions The mean and variance of a discrete probability distribution can easily be found using the formulae below. Solution: m ¼ð1Þð:2088Þþð2Þð:1582Þþð3Þð:1313ÞþÁÁÁþð8Þð:0370Þ¼3:5589 2 2 2 2 s ¼ð1 À 3:5589Þ ð:2088Þþð2 À 3:5589Þ ð:1582Þþð3 À 3:5589Þ ð:1313Þ 2 þÁÁÁþð8 À 3:5589Þ ð:0370Þ¼3:8559 We therefore can conclude that the mean number of programspﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃutilized was 3. Let the discrete random variable X represent the number of co-occurring addictive substances used by the subjects. The distribution is derived from a process known as a Bernoulli trial, named in honor of the Swiss mathematician James Bernoulli (1654–1705), who made significant contributions in the field of probability, including, in particular, the binomial distribution. When a random process or experiment, called a trial, can result in only one of two mutually exclusive outcomes, such as dead or alive, sick or well, full-term or premature, the trial is called a Bernoulli trial. The Bernoulli Process A sequence of Bernoulli trials forms a Bernoulli process under the following conditions. One of the possibleoutcomesisdenoted (arbitrarily)asa success,and the other isdenoted a failure. The trials are independent; that is, the outcome of any particular trial is not affected by the outcome of any other trial.
Opioids and clonidine (indirect cheap oxytrol master card, centrally acting α -adrenergic agonist) may be similarly added to enhance the quality and duration of spinal anesthesia discount oxytrol 2.5mg amex. A head-up position causes a hyperbaric solution to settle caudad and a hypobaric solution to ascend cephalad purchase oxytrol with paypal. A supine position causes hyperbaric solutions to settle in the most dependent area of the spine (T4–T8 with normal thoracic kyphosis) order discount oxytrol line, thereby limiting spinal anesthesia to T4 and below. Local anesthetic solutions may be made hyperbaric by addition of glucose or hypobaric by addition of ster- ile water. Test dose: Detects both subarachnoid and intravascular injection; typically 3 mL of 1. Incremental dosing: If aspiration is negative, a fraction of total intended local anesthetic dose is injected (typically 5 mL). Large enough dose for mild symptoms of intravascular injection but small enough to avoid seizures or cardiovascular compromise Rescue lipid emulsion (20% Intralipid, 1. The volume required to achieve same level decreases with age (secondary to age-related decreases in size or com- pliance of epidural space). Spread only partially affected by gravity; much less dramatic than spinal Failed epidural blocks: Subjective loss of resistance, variable anatomy of epidural space, and unpredictable spread of local anesthetic = lower success rate compared with spinal Unilateral block: Likelihood increases as the distance the catheter is threaded into the epidural space increases; if suspected, withdraw catheter 1 to 2 cm and reinject local anesthetic with the patient positioned with the unblocked side down. Segmental sparing: May be caused by septations within the epidural space; correct by injecting local anesthetic with the patient positioned with the unblocked segment down. Sacral sparing: Large size of L5, S1, and S2 nerve roots prevents adequate penetration of local anesthetic; elevat- ing the head of the bed and reinjecting may help achieve a more intense block of these large nerve roots. High protein binding and lipid solubility cause accumulation in the cardiac conduction system, leading to refractory arrhythmias. Ropivacaine: Less toxic than bupivacaine; roughly equal or slightly less in terms of potency, onset, duration, and quality of block Similar to spinal anesthesia, additives to the local anesthetics include opioids and α -adrenergic agonists. Onset may be accelerated with the addition of sodium bicarbonate (1 mEq/10 mL local anesthetic); particu- larly with the weaker bases (more ionized anesthetics): lidocaine, mepivacaine. One of the most commonly used regional techniques in pediatric anesthesia: Often combined with general anesthesia for intraoperative and postoperative analgesia: Urogenital, rectal, inguinal, and lower extremity surgeries Commonly performed after induction of general anesthesia 0. Used in anorectal surgery in adults: Provides dense sacral sensory blockade with limited cephalad spread 15 to 20 mL of 1. Within the sacral canal, the dural sac extends to the first sacral vertebra in adults and the third in infants; inadvertent intrathecal injection is more common in infants. Total spinal: Inadvertent intrathecal injection with attempted epidural or caudal anesthesia; rapid onset because of higher doses of medication (5–10 times that required for spinal anesthesia) Subdural injection: Inadvertent subdural injection of epidural doses of local anesthetic produces a clinical scenario similar to total spinal anesthesia except onset is delayed for 15 to 30 minutes; the same treatment is used. Epidural abscess: Incidence varies widely from one in 6500 to one in 500,000 epidurals. Four classic clinical stages (progression and time course may vary): (1) back or vertebral pain (intensified by percussion over the spine), (2) nerve root or radicular pain, (3) motor/sensory deficits and/or sphincter dysfunc- tion, and (4) paraplegia/paralysis. Intolerance to systemic analgesics—such as those with obstructive sleep apnea or at high risk for nausea—may benefit from the opioid-sparing effects of a regional analgesic. Patients with chronic pain and opioid tolerance may receive optimal analgesia with a con- tinuous peripheral nerve block. A comprehensive knowledge of anatomy and an understanding of the planned surgical procedure are important for selection of the appropriate regional anesthetic technique. Choice of local anesthetic: The decision of which local anesthetic to use for a particular nerve block depends on the desired onset, duration, and relative blockade of sensory and motor fibers. Examples include younger pediatric patients and some developmentally delayed individuals, as well as patients with dementia or movement disorders. Bleeding disorders or pharmacologic anticoagulation heightens the risk of local hematoma or hemorrhage, and this risk must be balanced against the possible regional block benefits. Placement of a block needle through a site of infection can theoretically track infectious material into the body, where it poses risk to the target nerve tissue and surrounding structures. Therefore, the presence of a local infection is a relative contraindication to performing a peripheral nerve block. Other risks associated with regional anesthesia include local anesthetic toxicity from intravascular injection or perivascular absorption. In the event of a local anesthetic overdose, seizure activity and cardiovascular collapse may occur. Supportive measures should begin immediately, including solicitation of assistance with a code blue, the initiation of cardiopulmonary resuscitation, Intralipid administration to sequester local anesthetic, and preparation for cardiopulmonary bypass. Preparation: Regional anesthetics should be placed in an area where American Society of Anesthesiologists standard monitors, supplemental oxygen, and resuscitative medications and equipment are readily available. Commonly used by surgeons to minimize incisional pain or as the sole anesthetic for minor, superficial procedures. Field blocks may be undesirable when they obscure the operative anatomy or when local tissue acidosis from infection prevents effective local anesthetic functioning. Using known anatomic rela- tionships and surface landmarks as a guide, a block needle is placed in proximity to the target nerve or plexus. When a needle makes direct contact with a sensory nerve, a paresthesia (abnormal sensation) is elicited in its area of sensory distribution. Nerve stimulation: An insulated needle concentrates electrical current at the needle tip, and a small wire attached to the needle hub connects to a nerve stimulator—a battery-powered machine that emits a small amount (0–5 mA) of electric current at a set interval (usually 1 or 2 Hz). When the insulated needle is placed in proximity to a motor nerve, muscle contractions are induced, and local anesthetic is injected. Although it is common to redirect the block needle until muscle contractions occur at a current less than 0. Ultrasonography uses high-frequency (1–20 mHz) sound waves emitted from piezoelectric crystals that travel at different rates through tissues of different densities, returning a signal to the transducer. Depending on the amplitude of signal received, the crystals deform to create an electronic voltage that is converted into a two-dimensional grayscale image. The degree of efficiency with which sound passes through a substance determines its echogenicity. Structures and substances through which sound passes easily are described as hypoechoic and appear dark or black on the ultrasound screen. In contrast, structures reflecting more sound waves appear brighter or white on the ultrasound screen and are termed hyperechoic. Continuous peripheral nerve blocks: Involves the placement of a percutaneous catheter adjacent to a periph- eral nerve followed by local anesthetic administration to prolong a nerve block. Potential advantages appear to depend on successfully improving analgesia and include decreasing resting and dynamic pain, supplemental analgesic requirements, opioid-related side effects, and sleep disturbances. In some cases, patient satisfaction and ambulation or functioning may be improved, an accelerated resumption of passive joint range of motion real- ized, and the time until discharge readiness as well as actual discharge from the hospital or rehabilitation center achieved. There are multiple types of catheters, including nonstimulating and stimulating, flexible and more rigid, and through-the-needle and over-the-needle catheters. As the nerve roots leave the intervertebral foramina, they converge, forming trunks, divisions, and cords and then finally terminal nerves. Three distinct trunks are formed between the anterior and middle sca- lene muscles and are termed superior, middle, and inferior given their vertical orientation. As the trunks pass over the lateral border of the first rib and under the clavicle, each trunk divides into anterior and posterior divisions. As the brachial plexus emerges below the clavicle, the fibers combine again to form three cords that are named according to their relationship to the axillary artery: lateral, medial, and posterior. At the lateral border of the pectoralis minor muscle, each cord gives off a large branch before terminating as a major termi- nal nerve. The lateral cord gives off the lateral branch of the median nerve and terminates as the musculocu- taneous nerve, the medial cord gives off the medial branch of the median nerve and terminates as the ulnar nerve, and the posterior cord gives off the axillary nerve and terminates as the radial nerve. Roots C5 to C7 are most densely blocked, and the ulnar nerve originating from C8 and T1 may be spared. Therefore, interscalene blocks are not appropriate for surgery at or distal to the elbow. Contraindications include local infection, severe coagulopathy, local anesthetic allergy, and patient refusal. A properly performed interscalene block invariably blocks the ipsilateral phrenic nerve. Horner syndrome (myosis, ptosis, and anhidrosis) may result from proximal tracking of local anesthetic and blockade of sympathetic fibers to the cervicothoracic ganglion. In a patient with contralateral vocal cord paralysis, respiratory distress may ensue. Other site-specific risks include vertebral artery injection (suspect if immediate seizure activity is observed), spinal or epidural injection, and pneumothorax.
Note the dramatic isolated late potentials recorded on both bipoles of the ablation catheter purchase oxytrol american express. Isopotential mapping represents a color map of progression of activation throughout the ventricle as referenced by the location of steep qS unipolar electrograms discount oxytrol 5 mg overnight delivery. At each point in time order oxytrol 5mg mastercard, activation is shown in white discount oxytrol 2.5 mg on-line, with recovery (or lower-voltage activation events) in the progression of colors from red to purple. The extent of the apical infarction produced in a porcine model is shown with the dark circle apical view). Activation seems to proceed to the area outside of the infarct in two specific places: at approximately 3:30 (white area in the left panel) and 9:00 (a smaller voltage, later activation in red in the right panel). There has been active investigation of the use of late potential ablation for substrate ablation techniques. This concept was used for surgical ablation by Guiraudon and coworkers in the 1980s. This suggests a level of organization for late potentials, but the governance of this organization has been difficult to determine. Finally, ablation of all late potential sites with individual ablation, often from both endocardial and epicardial surfaces, so-called scar homogenization, has been proposed. The presence of late potentials is also affected be the wavefront of activation, which adds another limitation to this approach. When approaching substrate- based ablation, we often use a mixed approach, depending on the nature of the procedure. If pacing within the scar from multiple sites suggests limited avenues of egress from the scar, limited isolation (“box isolation”) ablation is a viable option. Theoretically, noncontact mapping or large basket catheters would be expected to be effective in identification of target sites for ablation in poorly tolerated arrhythmias. One limitation is the lack of associated software to accurately locate the scar tissue (voltage) or sites of late activation. Moreover, an additional catheter is needed to ablate through or around the scar tissue that is identified by these techniques. In a study of a porcine model of infarction with inducible untolerated ventricular tachycardia, the Carto electroanatomic map provides the most accurate correlation with the anatomic scar when compared to these other technologies. Additional Procedures after Failed Catheter Ablation An important minority of patients continue to have clinically important recurrent ventricular tachycardia despite attempts at ablation. There has been a great deal of recent interest into various procedures that can serve to rescue these situations. Anter and colleagues described a cohort of eight patients with nonischemic cardiomyopathy who had surgical cryoablation performed following unsuccessful catheter ablation. Green icons denote sites with fractionated electrograms (not late) during sinus rhythm; gray icons denote sites with isolated late potentials (electrograms from three such sites shown in the insets) and red dots denote ablation sites. After relatively limited ablation, all of the late and fractionated electrograms were eliminated. Elimination of local abnormal ventricular activities: a new end point for substrate modification in patients with scar-related ventricular tachycardia. Several small case studies of renal artery denervation have suggested a potential for benefit but there are no controlled trials to support this effort. These macroreentrant circuits involve both scar tissue and functional barriers through which the impulse circulates. I prefer to target the spontaneous tachycardia or tachycardias originating in the same area at similar cycle lengths. These patients may have multiple, stable tachycardias, which may, depending on the investigator, be targets for ablation. However, the rapid untolerated tachycardias that may be induced in nearly 50% of such patients are not targeted for ablation in our laboratory. We have not found that such arrhythmias predict recurrences and sudden death due to these rapid arrhythmias. We use the scheme as shown in Figure 13-147 as a basis for regionalizing the ventricular tachycardias associated with coronary artery disease, which by and large arise (or at least critical components of which arise) in the left ventricular endocardium. We have seen four such cases in which successful ablation was carried out from a site on the right ventricular septum that demonstrated concealed entrainment. An example is shown in Figure 13-148 in a patient with an old inferior infarction. In addition, the right ventricular reference electrogram had both the same relationship to the stimulus as it did to the onset of the native electrogram. Occasionally, a macroreentrant circuit can be demonstrated with an impulse circulating around the edge of an aneurysm. This most often happens with inferior infarction in which the isthmus between the infarct and the annulus serves as the protected central common pathway of tachycardias that can go clockwise or counterclockwise. Electroanatomic mapping delineated the large inferoseptal aneurysm and demonstrated a macroreentrant circuit around this giant aneurysm. A single lesion delivered just at the superior edge of the septal border of the aneurysm terminated the tachycardia and left A-V conduction intact. While reentrant excitation can occasionally be demonstrated using Carto, as stated above, stimulation as described above and in Chapter 11, is required to accurately define the P. The demonstration of an “early meets late” pattern does not necessarily define the critical isthmus for ablation. A: A patient with a large ventricular aneurysm secondary to an old inferior infarction presented with incessant ventricular tachycardia. Of note is that the ventricular electrogram in the His bundle recording site demonstrated equally early activity. The His bundle electrogram was recorded less than 4 mm away from the left ventricular diastolic potential. B: Entrainment mapping from the left ventricular site (as well as the His bundle site) produced an exact entrainment map. C: Electroanatomical mapping defined the borders of an aneurysm (tan circles) and demonstrated reentrant excitation around this aneurysm. D: Because all three criteria were met in the left ventricle as well as at the His bundle recording site, it was elected to ablate at the left ventricular site to prevent the possibility of heart block. This has resulted from the observation at surgery that a subgroup of patients with blotchy infarctions and no aneurysms, usually on the inferior wall, have early activity noted on the epicardium. In some patients with inferior infarction, elements of the infarct scar are “protected” by the overlying posteromedial papillary muscle (Fig. Improved filtering protocols are being developed to provide better imaging in this situation (Fig. These investigators could not perform entrainment mapping for unclear reasons, nor did they simultaneously map the endocardium. Nevertheless, the ability in certain patients to use an epicardial approach via the pericardium has advantages in terms of catheter-stability, absence of stroke risk, absence of vascular injury, and absence of requirement for and complications of anticoagulation. A recent retrospective series from two laboratories with extensive experience using epicardial access showed that these procedures had a 7% major complication rate related to epicardial access and ablation. In our experience, if all the criteria for concealed entrainment are met, there is greater than a 90% chance of terminating the tachycardia with a single site ablation. In general, the success rate appears to be 70% to 75% with a 25% to 40% recurrence rate. While there are some who suggest that all tachycardia morphologies should be targeted for ablation, I think it is reasonable to target tolerated tachycardias arising from a similar area as a clinical tachycardia. We have not found induced, rapid tachycardias that are untolerated to be clinically meaningful in patients who present only with tolerated tachycardias. If the patient is on drugs at the time of the ablation, one must maintain the drugs because the ablation actually should be considered a form of hybrid therapy in combination with the drug. Intrapericardial introduction of ablation catheter in a patient with ventricular tachycardia due to an old inferior infarction is shown. Application of radiofrequency energy at this site terminates the ventricular tachycardia in 6 seconds. Nonsurgical transthoracic epicardial catheter ablation to treat recurrent ventricular tachycardia occurring late after myocardial infarction. It is of interest that single lesions sometimes eliminate multiple morphologically distinct tachycardias. Another possibility is that the lesion increased the length of the central common pathway by increasing the barrier around which the impulse was circulated.
Factors associated with women’s decisions to seek treatment for urinary incontinence discount 5mg oxytrol otc. A survey of help-seeking and treatment provision in women with stress urinary incontinence buy oxytrol amex. Self-reported urinary incontinence and factors associated with symptom severity in community dwelling adult women: Implications for women’s health promotion buy oxytrol 5 mg free shipping. Moore K buy oxytrol 5mg, Bradley C, Burgio B, Chambers T, Hagen S, Hunter H, Imamura M, Thakar R, Williams K. Incontinence: Proceedings from the Fifth International Consultation on Incontinence. Incontinence: Proceedings from the Fifth International Consultation on Incontinence. Developing an internationally-applicable service specification for continence care: Systematic review, evidence synthesis and expert consensus. Stigma and micro aggressions experienced by older women with urinary incontinence: A literature review. A population-based study of urinary symptoms and incontinence: The Canadian Urinary Bladder Survey. Attitudes toward urinary incontinence among community nurses and community- dwelling older people. The social consequences of living with and dealing with incontinence—A carer’s perspective. Disease stigma and intentions to seek care for stress urinary incontinence among community-dwelling women. Living with faecal incontinence: Trying to control the daily life that is out of control. National Institutes of Health state-of-the-science conference statement: Prevention of fecal and urinary incontinence in adults. A qualitative study of managing incontinence with people with dementia living at home. Effects of stigma on Chinese women’s attitudes towards seeking treatment for urinary incontinence. Talking with others about stigmatized health conditions: Implications for managing symptoms. Urinary incontinence—Prevalence, impact on daily living and desire for treatment: A population-based study. The meaning of women’s experience of living with long-term urinary incontinence is powerlessness. The prevalence and determinants of health care-seeking behavior for urinary incontinence in United Arab Emirates women. Reasons for not seeking medical help for severe pelvic floor symptoms: A qualitative study in survivors of gynaecological cancer. A quality of life survey of individuals with urinary incontinence who visit a self-help website: Implications for those seeking healthcare information. A hypothesis for the natural history is presented with possible implications for preventative strategies. During pregnancy the endopelvic fascial attachments of the bladder neck and distal sphincter are weakened possibly due to hormonal influences . Progesterone reduces urethral closure pressures and produces connective changes [3,4] that probably contribute to the high incidence of any antenatal incontinence. If the endopelvic fascial attachments and sphincter function are not damaged at delivery, then the changes seen antenatally are likely to revert to the nonpregnant state with the return of urethral function and continence. However, if these structures are damaged or are inherently weak in the nonpregnant state, then recovery might not arise. Support for this hypothesis comes from studies suggesting the presence of a constitutional factor, e. This, along with further deliveries, aging, menopause, and muscle weakness, seems to increase the risk of long-term incontinence . In a study of women reassessed 6 years after childbirth , there was a rate of new-onset incontinence of approximately 30% in women who had been continent at 3 months postpartum. However, in 27% who were incontinent at 3 months, there was spontaneous remission at 6 years. Of particular interest were those women who were incontinent prior to pregnancy; there was a markedly increased risk for leakage at 6 years. These interesting findings suggest that there are women at risk of incontinence, while in others there is spontaneous remission. Based on data from a systematic review, during the first 3 months postpartum, the pooled prevalence of any postpartum incontinence is 33%, with longitudinal studies showing small changes in prevalence in the first year after childbirth . A larger 2-year study of 64,650 women aged 36–55 years showed complete remission in 13. A 2-year study of noninstitutionalized women over 60 years showed a 1- year remission rate of 12% . A study followed 2025 women aged over 65 years for 6 years (baseline prevalence of urgency incontinence was 36. This study showed for urgency incontinence, the 3-year incidence and remission rates between the third and sixth years were 28. For stress incontinence, the 3-year incidence and remission rates between years 3 and 6 were 28. A longitudinal Swedish population-based study of over 100 women from 1991 to 2007 showed incidence and remission rates of 21% and 34%, respectively . The reported incidence for cystocele is around 9 per 100 woman-years, 6 per 100 woman-years for rectocele, and 1. A 4-year observational study  in postmenopausal women showed an overall 1- and 3-year prolapse incidence of 26% and 40%, respectively. This study  also showed a 1- and 3-year resolution risk of 21% and 19%, respectively. The study also showed that over 3 years, the maximum vaginal descent increased by at least 2 cm in 11% of the women and decreased by at least 2 cm in 2. In older age groups (>70 years), many are symptomatic and approximately 11% will undergo surgery, but there are few data on the numbers treated conservatively, e. The majority (78%) demonstrated no change in the leading edge of the prolapse between the first and the last visit, following which 63% still continued observation . Prevention can be classified as primary (interventions in asymptomatic individuals to reduce known risk factors for the development of a disease) or secondary (to detect symptoms at an early stage and to intervene to stop further development or to improve the prognosis of the condition). To stop recurrence of an illness or preventing it becoming chronic is tertiary prevention. There are known predisposing factors such as age, obesity, family history, parity/vaginal childbirth, and surgery. Identification of individuals at risk might help with implementing preventative measures. Although the prevalence of incontinence is increased in the elderly, the two do not necessarily have a cause-and-effect relationship; other pathological processes associated with aging might be responsible. Likewise, management of other risk factors such as chronic cough, smoking, and adjusting medication that has an adverse effect on the bladder could help incontinence (e. Regular toileting, easy access to toilets, restricting fluids (especially caffeine), and prevention of urinary tract infection, e. Menopause and Hormone Replacement Therapy There is a definite aging process in the lower urinary tract, resulting in atrophic change and poor urethral function. Urgency 126 Urgency is a distressing symptom for the older patient with restricted mobility, causing panic and anxiety on the sensation of bladder fullness. Often, patients void more frequently to prevent urgency incontinence, which can have the opposite effect, by reducing bladder capacity and worsening the symptoms. There is evidence that patients with urgency incontinence (more than once a week) are at increased risk of falls and bone fracture than in those without . One study in morbidly obese women undergoing surgically induced weight loss showed subjective and urodynamic improvement in incontinence 1 year after surgery . A randomized trial in 338 overweight and obese women found that a mean weight loss of 8% in the intervention group (vs. Familial and Genetic Factors Identification of risk groups is important and family history might be relevant. A small study in four pairs of postmenopausal identical twins with different parity status, i. Childbirth Vaginal birth probably has an important role in the pathogenesis of pelvic floor dysfunction.
This has meant that expert opinions were included in a “numerically” more balanced manner oxytrol 2.5mg online. However order oxytrol mastercard, no “methods” paragraph was given to explain explicitly how decisions on topics to include were made nor how evidence and expert opinion were prioritized order oxytrol 2.5mg line, included buy generic oxytrol 2.5 mg on-line, or excluded beyond acknowledgement of the commenting experts in a final paragraph. Where genuine evidence is lacking or conflicting, it is preferable that expert opinion is separately added to recommendations in a transparent and explicit manner. Standards to produce evidence- based clinical practice guidelines have been developed , with guidance manuals . In the modern era of information technology, transparency, accountability, and complex multidisciplinary responsibilities cannot be ignored; expert opinion is only acceptable where evidence is lacking and must be clearly marked and explained as being expert opinion. It may also be relevant in other fields, 1846 such as consumer perspectives or economic issues. The process by which the draft standard was created will be evaluated according to preset criteria. The draft standard will be circulated to all members by website publication for commenting over a period of 3 months. Explicit criteria for the inclusion or exclusion of comments should be developed and each comment should be accompanied by a narrative explaining the reason why it was either included in or excluded from the final version. All comments and accompanying narrative will be published on the relevant document web forum. Copublication with other journals can be considered if relevant, within copyright regulations. Translation into other languages will be supported; for terminology standards, this will require that appropriate linguistic validation procedures are followed (for an example of the application of linguistic validation in the context of translation of symptom assessment tools, see Acquadro et al. The standardisation of terminology of lower urinary tract function: The International Continence Society Committee on Standardisation of Terminology. The standardisation of terminology of lower urinary tract function: Report from the Standardisation Subcommittee of the International Continence Society. Good urodynamic practices: Uroflowmetry, filling cystometry, and pressure-flow studies. Problems in the handling of clinical and research evidence by medical practitioners. Development and aftercare of clinical guidelines: The balance between rigor and pragmatism. The primary objective was to better select candidates for surgical intervention and choose the appropriate procedure in order to reduce recurrences by allowing accurate identification and objective measurement of prolapse and simultaneous topographic assessment of the pelvis at rest and straining [1–5]. Imaging protocols vary according to patient positioning, filling media, pelvic organ opacification, patient maneuvers (i. In a recent systematic review, seven different reference lines in relation to a wide variety of reference points have been used in different studies with imprecise definition or interchangeable use of some lines, e. The soft tissue–based reference lines can underestimate organ movement relative to the pelvic bones. The systems defined relative to the scanner are affected by intra- and interindividual differences in the pelvic inclination angle at rest and strain. The hypothesis is biologically plausible since variations in pelvic inclination alter the direction of intra-abdominal vector forces and the degree of transmission of abdominal pressure onto the pelvic floor, thereby influencing the development of pelvic floor weakness and subsequent prolapse . Classifications and reference systems are widely used in medicine and define groups by similar properties, e. It results in reliable distance calculation independent of the anteroposterior midsagittal location of the organ because it is not oblique. John DeLancey, which implemented the basic geometrical theorems to solve this measurement problem. A systematic review of clinical studies on dynamic magnetic resonance imaging of pelvic organ prolapse: The use of reference lines and anatomical landmarks. Dynamic assessment of pelvic floor and bony pelvis morphologic condition with the use of magnetic resonance imaging in a multi-ethnic, nulliparous, and healthy female population. Visibility of pelvic organ support system structures in magnetic resonance images without an endovaginal coil. Marshall-Marchetti-Krantz procedure, 826–827 Marshall–Marchetti–Kranz procedure, 1090 vs. Dana Professor of Medicine Harvard Medical School Chief of the Cardiovascular Division, Beth Israel Deaconess Medical Center Director, Harvard-Thorndike Electrophysiology Institute and Arrhythmia Service, Beth Israel Deaconess Medical Center, Boston, Massachusetts Dedication This book is dedicated to my family—Sylvie, Elan, Sydney, Rachel, Todd, Stephanie, Jesse, and particularly, to my wife Joan—for their love, support, and understanding. Foreword: Historical Perspectives The study of the heart as an electrical organ has fascinated physiologists and physicians for nearly a century 1 2 and a half. Matteucci studied electrical current in pigeon hearts, and Kölliker and Müller studies discrete electrical activity in association with each cardiac contraction in the frog. Study of the human electrocardiogram 3 4 awaited the discoveries of Waller and, most important, Einthoven, whose use and development of the string galvanometer permitted the standardization and widespread use of that instrument. Almost simultaneously, anatomists and pathologists were tracing the atrioventricular (A-V) conduction system. Many of the pathways, both normal and abnormal, still bear the names of the men who described them. This group of men included 5 His, who discovered the muscle bundle joining the atrial and ventricular septae that is known as the common A- V bundle or the bundle of His. During the first half of the 20th century clinical electrocardiography gained widespread acceptance, and, in feats of deductive reasoning, numerous electrocardiographers contributed to the understanding of how the cardiac impulse in man is generated and conducted. Nevertheless, combining those carefully made observations of the anatomists and the concepts developed in the physiology laboratory, these researchers accurately described, or at least hypothesized, many of the important concepts of modern electrophysiology. These included such concepts as slow conduction, concealed conduction, A-V block, and the general area of arrhythmogenesis, including abnormal impulse formation and reentry. Even the mechanism of pre-excitation and circus movement tachycardia were accurately 7 described and diagrammed by Wolferth and Wood from the University of Pennsylvania in 1933. The diagrams in that manuscript are as accurate today as they were hypothetical in 1933. Much of what has followed the innovative work of investigators in the first half of the century has confirmed the brilliance of their investigations. In the 1940s and 1950s, when cardiac catheterization was emerging, it became increasingly apparent that luminal catheters could be placed intravascularly by a variety of routes and safely passed to almost any region of the heart, where they could remain for a substantial period of time. Although the early years of intracardiac recording in man were dominated by descriptive work exploring the presence and timing of His bundle activation (and that of a few other intracardiac sites) in a variety of spontaneously occurring physiologic and pathologic states, a quantum leap occurred when the technique of 14 programmed stimulation was combined with intracardiac recordings by Wellens. Use of these techniques subsequently furthered our understanding of the functional component of the A-V specialized conducting system, including the refractory periods of the atrium, A-V node, His bundle, Purkinje system, and ventricles and enables us to assess the effects of pharmacologic agents on these parameters, to induce and terminate a variety of tachyarrhythmias, and, in a major way, has led to a greater understanding of the electrophysiology of the human heart. Shortly thereafter, enthusiasm and inquisitiveness led to placement of an increasing number of catheters for recording and stimulation to different locations with the heart, first in the atria and thereafter in the ventricle. This first led to development of endocardial catheter mapping techniques to define the location of bypass tracts 15 16 and the mechanisms of supraventricular tachyarrhythmias. Several studies validated the sensitivity and specificity of programmed stimulation for induction of uniform tachycardias, and the nonspecificity 19 20 of polymorphic arrhythmias induced with vigorous programmed stimulation was recognized. This led to the recognition of the subendocardial origin of the majority of ventricular tachyarrhythmias, associated with coronary artery disease and the development of subendocardial resection as a therapeutic cure for this 24 arrhythmia. For the next decade, electrophysiologic studies continued to better understand the mechanisms of arrhythmias in man by comparing the response to programmed stimulation in man in the response to in vitro and in vivo studies of abnormal automaticity, triggered activity caused by delayed and early afterdepolarizations, and anatomical functional reentry. These studies, which used programmed stimulation, endocardial catheter mapping, and response of tachycardias to stimulation and drugs, have all suggested that most sustained paroxysmal tachycardias were due to reentry. Further exploration of contributing factors (triggers), such as the influence of the autonomic nervous system or ischemia, will be necessary to further enhance our understanding of the genesis of the arrhythmias. This initial decade or so of electrophysiology could be likened to an era of discovery. Subsequently, and overlapping somewhat with the era of discovery, was the development of the concept and use of programmed stimulation as a tool for developing therapy for arrhythmias. The ability to reproducibly initiate and terminate arrhythmias led to the development of serial drug testing to assess antiarrhythmic 35 efficacy. The ability of an antiarrhythmic drug to prevent initiation of a tachycardia that we reliably initiated in the control state appeared to predict freedom from the arrhythmia in the 2- to 3-year follow-up. This was seen in many nonrandomized clinical trials from laboratories in the early 1980. The persistent inducibility of an arrhythmia universally predicted an outcome that was worse than that in patients in whom tachycardias were made noninducible. The natural history of recurrences of ventricular tachyarrhythmias (or other arrhythmias for that matter) and the changing substrate for arrhythmias were recognized potential imitations of drug testing. It was recognized very early that programmed stimulation was not useful in selecting drugs to treat ventricular tachyarrhythmias in patients without coronary artery disease (i.
On the average buy oxytrol now, two students per hour report for treatment to the first-aid room of a large elementary school purchase oxytrol 5mg free shipping. A Harris Interactive poll conducted in Fall cheap oxytrol 5mg online, 2002 (A-15) via a national telephone survey of adults asked cheap 2.5 mg oxytrol amex, “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. In the chapters that follow, we will see how sampling distributions make statistical inferences valid. Sampling Distributions: Construction Sampling distributions may be constructed empirically when sampling from a discrete, finite population. List in one column the different distinct observed values of the statistic, and in another column list the corresponding frequency of occurrence of each distinct observed value of the statistic. The actual construction of a sampling distribution is a formidable undertaking if the population is of any appreciable size and is an impossible task if the population is infinite. In such cases, sampling distributions may be approximated by taking a large number of samples of a given size. We can recognize the difficulty of constructing a sampling distribution according to the steps given above when the population is large. We also run into a problem when considering the construction of a sampling distribution when the population is infinite. The best we can do experimentally in this case is to approximate the sampling distribution of a statistic. Although the procedures involved are not compatible with the mathematical level of this text, sampling distributions can be derived mathematically. The interested reader can consult one of many mathematical statistics textbooks, for example, Larsen and Marx (1) or Rice (2). In the sections that follow, some of the more frequently encountered sampling distributions are discussed. Let us see how we might construct the sampling distribution by following the steps outlined in the previous section. The mean, m, of this population is equal P to xi=N ¼ 10 and the variance is P 2 2 xi À m 40 s ¼ ¼ ¼ 8 N 5 Let us compute another measure of dispersion and designate it by capital S as follows: P 2 2 xi À m 40 S ¼ ¼ ¼ 10 N À 1 4 We will refer to this quantity again in the next chapter. We wish to construct the sampling distribution of the sample mean, x, based on samples of size n ¼ 2 drawn from this population. Samples Above or Below the Principal Diagonal Result When Sampling Is Without Replacement. In general, when sampling is with replacement, the n number of possible samples is equal to N. We may construct the sampling distribution of x by listing the different values of x in one column and their frequency of occurrence in another, as in Table 5. It was stated earlier that we are usually interested in the functional form of a sampling distribution, its mean, and its variance. We now consider these characteristics for the sampling distribution of the sample mean, x. Sampling Distribution of x: Functional Form Let us look at the distribution of x plotted as a histogram, along with the distribution of the population, both of which are shown in Figure 5. We note the radical difference in appearance between the histogram of the population and the histogram of the sampling distribution of x. Whereas the former is uniformly distributed, the latter gradually rises to a peak and then drops off with perfect symmetry. Sampling Distribution of x: Mean Now let us compute the mean, which we will call mx, of our sampling distribution. Thus, P xi 6 þ 7 þ 7 þ 8 þÁÁÁþ14 250 mx ¼ n ¼ ¼ ¼ 10 N 25 25 We note with interest that the mean of the sampling distribution of x has the same value as the mean of the original population. It is of interest to observe, however, that the variance of the sampling distribution is equal to the population variance divided by the size of the sample used to obtain the sampling distribution. That is, s2 8 2 sx ¼ ¼ ¼ 4 n 2 pﬃﬃﬃ2 pﬃﬃﬃ The square root of the variance of the sampling distribution, sx ¼ s= n is called the standard error of the mean or, simply, the standard error. These results are not coincidences but are examples of the characteristics of sampling distributions in general, when sampling is with replacement or when sampling is from an infinite population. To generalize, we distinguish between two situations: sampling from a normally distributed population and sampling from a nonnormally distributed population. Sampling Distribution of x: Sampling from Normally Distrib- uted Populations When sampling is from a normally distributed population, the distribution of the sample mean will possess the following properties: 1. The mean, mx, of the distribution of x will be equal to the mean of the population from which the samples were drawn. The variance, s2 of the distribution of x will be equal to the variance of the population x divided by the sample size. Sampling from Nonnormally Distributed Populations For the case where sampling is from a nonnormally distributed population, we refer to an important mathematical theorem known as the central limit theorem. The importance of this theorem in statistical inference may be summarized in the following statement. The Central Limit Theorem Given a population of any nonnormal functional form with a mean m and finite variance s2, the sampling distribution of x, computed from samples of size n from this population, will have mean m and variance s2=n and will be approximately normally distributed when the sample size is large. Note that the central limit theorem allows us to sample from nonnormally distributed populations with a guarantee of approximately the same results as would be obtained if the populations were normally distributed provided that we take a large sample. The importance of this will become evident later when we learn that a normally distributed sampling distribution is a powerful tool in statistical inference. In the case of the sample mean, we are assured of at least an approximately normally distributed sampling distribution under three conditions: (1) when sampling is from a normally distributed population; (2) when sampling is from a nonnormally distributed population and our sample is large; and (3) when sampling is from a population whose functional form is unknown to us as long as our sample size is large. The logical question that arises at this point is, How large does the sample have to be in order for the central limit theorem to apply?