By G. Muntasir. University of Wisconsin-Stout. 2018.
This lesion represents a com m unication between the graft and a confined space in the tissue sur- rounding the graft and is a com m on finding in dialysis patients clozapine 100 mg free shipping. C buy 50mg clozapine otc, A pseudoaneurysm in a patient with a 3-year-old left groin PTFE graft discount clozapine 100mg free shipping. The lateral area of the loop was initially replaced, and when this was healed C and functioning well the m edial segm ent was replaced. Vascular steal is a com m on problem of dialysis access sites. The principle of steal is related to two phenom ena: 1) calcification or stenosis in the inflow arterial seg- m ent proxim al to an access site (so that the native artery cannot dilate to m eet the increas- ing demands for flow volume); 2) and an outflow arterial bed in parallel to the fistula origin with higher net vascular resistance than the fistula conduit. If both of these are present, blood flow is diverted to the access site in association with a drop in perfusion pressure to the m ost acral tissues, the fingers. W hen steal is severe, traum a to the digits leads to gan- grene. Several treatm ent strategies are available to the surgeon. The access can be “band- ed,” or purposefully stenosed at its origin to divert flow to the ischem ic site. The access can be revised using a tapered graft or the point of origin of the access can be m oved m ore proxim ally in the arterial tree, in the hope of allowing full flow without diverting distal perfusion pressure. Additionally, one can perform a variety of bypass procedures to divert higher-pressure proxim al blood to increase distal perfusion pressure. In severe cases, either the access or the distal digits m ay be sacrificed to preserve the other. M easurem ent of graft blood flow (using Doppler im aging, ultra- sound dilution, or another m ethod) is increasingly available and m ay be the best screening m ethod. W hen graft flow declines below dialyzer blood flow (E), blood flows between the needles (F) in a retrograde direction. This developm ent is called recirculation, since it results in repeated uptake and dialysis of blood that has just been dialyzed. Recirculation can be detected by finding evidence that blood from the venous cannula is being taken up by the arterial cannula. This is m ost often recognized by the finding of an arterial blood urea nitrogen value below that in blood entering the graft. A stenotic lesion in an outflow vein tends to increase the pressure in the vein and graft (G ) between the stenosis and the venous nee- dle. This pressure usually ranges from 25 to 50 m m H g but m ay increase to m ore than 70 m m H g in the presence of stenosis. This pressure can be m easured directly or can be estim ated from the venous pressure m onitor on the dialysis m achine at zero blood FIGURE 5-18 flow (adjusting for the difference in height between the graft and Vascular access screening m ethods. To increase accuracy, this pressure can be norm al- dence of throm bosis, the risk of which increases when graft flow ized by dividing it by the m ean arterial pressure. M ore com m only, rates (A) fall below 600 to 700 m L/m in, particularly with stenotic this intragraft pressure is determ ined indirectly by using the dialysis lesions in or near the graft. Various norm al graft, owing to the resistance in the venous needle. The use of central vein catheters has grown significantly over the past several years. These catheters were at one tim e used only on a tem porary basis and served as a “bridge” to perm anent vascular access. Im provem ents in catheter design and function com bined with ease of insertion have increased use of central vein catheters in dialysis units. To m inim ize the risk of central vein stenosis and subsequent throm bo- sis, central vein catheters should be inserted preferentially into the right internal jugular vein, regardless of whether they are being used for tem porary or m ore perm anent purposes. The typical posi- tioning of a double-lum en catheter, A, is with its tip at the junction of the right atrium and the superior vena cava. The catheter has been “tunneled” underneath the skin so that the exit site (large arrow) is located just beneath the right clavicle and distant from the insertion site (sm all arrow). This catheter also has a cuff into which endothelial cells will grow and produce a biologic barrier to bacterial m igration. B, Chest radiograph showing a dialysis central vein catheter that is com posed of two separate single-lum en catheters that have been inserted into the right internal jugular vein. The distal tip of the venous catheter is positioned just above the right atrium. Care m ust be taken, however, to ensure proper placem ent of catheters with this type of design, because the two single lum ens are radiographically indistinguishable. A, Venogram of the central outflow veins perform ed in a patient with a left upper extrem ity polytetrafluoroeth- ylene graft and arm edem a, B. The most common cause for stenosis or thrombosis of the central venous system is previous injury from indwelling central vein catheters. Central vein stenosis may not become apparent until an arteriovenous anastomosis is created. This increases blood flow in the outflow veins and may overwhelm a compromised central vein, resulting in the appearance of superficial collateral veins on the neck and chest wall in addition to ipsilateral arm edema. In this example, the occlusion was crossed using an angiographic catheter, and thrombolytic therapy was administered. C, Venography performed after thrombolysis demonstrates severe stenosis of the innominate vein and the superior vena cava (arrow). W hen angioplasty fails, metal stents are intro- duced to treat outflow vein occlusion. These stents are either balloon expandable or self-expanding. The stages of deployment of the self- expanding W allstent (Schneider, Inc, Division of Pfizer Hospital Products, M inneapolis, M N) are seen in these radiographs. A, The radiopaque stent is positioned across the lesion to be treated. B, As the deployment envelope is gradually withdrawn, the stent begins to expand (arrow). These stents shorten during deployment, and this factor must be taken into consideration for proper placement. C, An angioplasty balloon (arrow) is placed in the proximal portion of this completely deployed stent to achieve further expansion. E, A postprocedure venogram demonstrates no residual stenosis. D E FIGURE 5-22 Central vein catheter complications. A, This radiograph demonstrates the tip of this dialy- sis catheter abutting the wall of the left innominate vein at its junction with the supe- rior vena cava. To maintain adequate dialysis flow rates and minimize fibrin sheath forma- tion, it is important for the catheter tip to be in the superior vena cava, near or in the right atrium.
Naturally occurring reduced cholesterol may also be associated with non–illness-related mortality (116 buy clozapine 25 mg on line, 120–123) quality clozapine 50 mg, largely attributable to suicide (116 order 25 mg clozapine visa,122). Low Vasopressin serum cholesterol has been reported in psychiatric inpatients Whereas Virkkunen et al. Reduced serum vasopressin concentrations among impulsive and nonim- cholesterol has also been related to the severity of borderline pulsive violent offenders (8), Coccaro et al. It is also found in male forensic patients (130), aggres- sons, particularly men (108). Despite a significant inverse sive conduct-disordered children and adolescents with at- correlation between CSF vasopressin and PRL[d-FEN] re- tention deficit disorder (131), and suicidal adolescents sponse, the positive relationship between aggression and (132). CSF vasopressin remained even after the influence of PRL[d-FEN] response on the aggression score was taken into account. These data are consistent with those from MOLECULAR GENETICS animal studies in which vasopressin antagonists reduced ag- gression in golden hamsters, whereas 5-HT uptake inhibi- An understanding of the molecular genetics of impulsive tors increased central 5-HT activity and reduced central aggression is currently emerging with the rise of association vasopressin concentration and levels of aggressive behavior studies involving various DNApolymorphisms of candidate in the same species (109). One of the first notable studies in this area was that human studies may be accounted for by significant differ- of Brunner et al. The presence of this mutation function also contributed to failures to inhibit responses to was associated with evidence of altered catecholamine me- stimuli associated with punishment on a 'go/no-go' learn- tabolism (i. Al- cerebral dysfunction has also been related to increased hos- though no other families with this specific MAO A point tility. Verbal signal decoding and P300 amplitudes in an mutation have been reported, this report highlighted the evoked potential paradigm predicted impulsiveness and potential of the candidate gene approach to the molecular anger in prison inmates (147). In terms of regional localiza- genetics of aggression. At about the same time, Nielson et tion, neuropsychological tasks sensitive to frontal and tem- al. Thus, neuropsychological and associated with a reduction of CSF 5-HIAA concentration cognitive studies do suggest that abnormalities of higher in impulsive violent offenders (nearly all with DSM-III integrative functions, consistent with reduced cortical in- IED) (134). In the same study, the presence of the L allele hibitory influences on aggression, result in more disinhibi- was also associated with history of suicide attempts in all tion of aggressive behaviors. Although this finding was not replicated laboratory paradigms may discriminate aggressive individu- by Abbar et al. The PSAP has been externally validated in violent offenders and more specifically for severe suicide attempts. However, sional measures of impulsive aggression (137). In this brief the heritability of these laboratory measures has not been report of only 21 personality-disordered subjects, those with systematically assessed in studies of families or sibs of impul- the LL genotype had significantly higher aggression scores sive or aggressive probands, a logical prerequisite to an endo- than subjects with the UU genotype. However, an associa- phenotypic approach to borderline personality disorder. It Neuroanatomy of Aggression may be that the TPH polymorphism is in linkage disequilib- rium with different genes in different populations. Lappa- Prefrontal cortex, particularly prefrontal orbital cortex and lainen et al. Astudy of a 5- roles in the generation of aggression as well. The critical HT6 receptor allelic variant in patients with schizophrenia role of prefrontal orbital cortex is exemplified by the case and in controls was negative for an association with aggres- of Phineas Gage, a solid, upstanding railroad worker, who, sive behavior (141). NEUROPSYCHOLOGY OF AGGRESSION Other clinical cases support the central role of orbital pre- frontal cortex in regulation of aggression (153–157). Irrita- The relationship between aggression and neuropsychology bility and angry outbursts have also been associated with is in part dependent on the syndrome in which aggression damaged orbital frontal cortex in neurologic patients (158), is observed. For example, the cognitive impairment of de- and frontal and temporal hypoperfusion has been noted mentia may be associated with aggressive behavior. Lesions of prefrontal lescents with conduct disorder, verbal processing deficits are cortex, particularly orbital frontal cortex, early in childhood associated with greater aggressiveness and antisocial behav- can result in antisocial disinhibited, aggressive behavior later ior (144). Low executive cognitive function is also related in life (160). Chapter 119: Pathophysiology and Treatment of Aggression 1715 Temporal lobe lesions have also been associated with a in orbital frontal cortex (176). These deficits were more susceptibility to violent behavior, as suggested by multiple pronounced in persons without psychosocial deprivation case reports of patients with temporal lobe tumors. In a study of patients with personality disorders, an study of violent patients, many anterior inferior temporal inverse relationship was found between life history of aggres- lobe tumors were reported (161,162), and aggressive behav- sive impulsive behavior and regional glucose metabolism ior has been associated with temporal lesions (163). Al- in orbital frontal cortex and right temporal lobe. Patients though temporal disease may express itself in a variety of meeting criteria for borderline personality disorder had de- ways, there does appear to be a clear association between creased metabolism in frontal regions corresponding to temporal pathology and aggressive behavior. Single photon emission computed tomography with rage attacks, and studies of patients who have under- studies have also suggested reduced perfusion in prefrontal gone amygdalectomy (164), although destructive behaviors cortex, as well as focal abnormalities in left temporal lobe have also been observed in the context of coagulation of the and increased activity in anteromedial frontal cortex in lim- amygdala (165). Patients with bilateral amygdala damage bic system in aggressive persons with reduced prefrontal judged unfamiliar persons to be more trustworthy than con- perfusion in antisocial personality-disordered alcoholism trols, a finding consonant with the role of the amygdala in (179), and hypoperfusion in the left frontoparietal region social judgments of potential threat (166). The association of violent behavior with aggressive be- Cingulate cortex has also been implicated especially in pos- havior with localized seizure activity provides a further guide terior regions in aggressive borderline patients (178), a find- to brain regions implicated in the modulation of aggression. However, only a few patients with temporal Extensive connections between amygdala and prefrontal lobe epilepsy engage in aggressive behaviors in the interictal cortex have been described, suggesting an inhibitory influ- or periictal periods (170–172). These clinical correlations, ence of frontal cortex on the amygdala (181). Amygdalo- although pointing to regions of interest for imaging studies, tomy has been associated with reduced aggressive outbursts cannot directly address the circuitry involved in impulsive in patients with intractable aggression (182), but there have aggression in the absence of specific neurologic disease. Imaging Neurotransmitter Systems in Structural Imaging and Aggression Aggression Reduced prefrontal gray matter has been associated with Serotonin autonomic deficits in patients with antisocial personality disorders characterized by aggressive behaviors (173). Al- Ascending serotonergic neurons from the raphe nuclei though these deficits are not visually perceptible, they reach project widely throughout the brain, including projections statistical significance and are consistent with the neurologic to dorsolateral prefrontal cortex and medial temporal lobe. Diffuse tracts extend from dorsal and medial raphe project Functional Imaging and Aggression to frontal lobe. Both 5-HT2A and 5-HT1A receptors are One technique used to identify brain activity in individuals found in high concentrations in human prefrontal cortex, as displaying aggressive behavior is the assessment of in vivo are 5-HT transporter sites (183), and patients with localized cerebral glucose metabolism through positron emission to- frontotemporal contusions show significantly lower 5-HT mography. Studies of this type tend to implicate brain hypo- metabolites in CSF than patients with diffuse cerebral con- metabolism in a variety of regions but particularly frontal tusions (184). Greater -CIT binding to 5-HT transporters and temporal cortex. In psychiatric patients with a history has also been reported in nonhuman primates with a higher of repetitive violent behavior, decreased blood flow consis- -CIT binding associated with greater aggressiveness (185). In a study of homicide gressive behavior in posterior orbital frontal cortex and me- offenders, bilateral diminution of glucose metabolism was dial frontal cortex in the amygdala, whereas increased 5- observed in both medial frontal cortex and at a trend level HT2A number in orbital frontal cortex, posterior temporal 1716 Neuropsychopharmacology: The Fifth Generation of Progress cortex, and amygdala have been correlated with prosocial may have a disinhibiting effect on the generation of aggres- behavior in primates (186). Thus, serotonergic modulation sion by amygdala and related structures.
A meta-analysis of these 4 studies representing 411 patients estimated an odds ratio (OR) of 4 cheap clozapine 100 mg free shipping. Forest plot for restoration of sinus rhythm for monophasic versus biphasic waveforms Study name Odds ratio and 95% CI Odds Lower Upper ratio l imit l imit Ricard discount clozapine 25mg overnight delivery, 2001 4 buy clozapine 25 mg amex. In the other two studies, there was no 187,202 statistically significant difference between the two approaches. A meta-analysis of these 4 studies involved 393 patients and estimated an OR of 0. There was some evidence of heterogeneity (Q-value=9. In the study in which the crossover was specified in the protocol, there was no statistically significant difference in success with the anteroposterior second shock versus the 183 anterolateral second shock (42% vs. In the study in which crossover to the alternative approach was allowed, 8 of 12 patients in whom the anterolateral approach failed were successfully cardioverted with the anteroposterior approach, and neither of the 2 patients in whom the anteroposterior approach failed was successfully cardioverted with the anterolateral 175 approach. No statistical testing was done to compare these results. Forest plot of restoration of sinus rhythm for anterolateral versus anteroposterior electrode placement Study name Odds ratio and 95% CI Odds Lower Upper ratio limit limit Alp, 2000 2. A meta-analysis of these 3 studies represented 432 patients and estimated an OR of 0. Forest plot of restoration of sinus rhythm for 200 J versus 360 J monophasic initial shocks Study name Odds ratio and 95% CI Odds Lower Upper ratio limit limit Joglar, 2000 0. In the third study, a larger proportion of patients had restoration of sinus rhythm with the higher biphasic energy levels (7% with 20J, 23% with 50J, 63% with 198 100J, and 83% with 200J), but the study did not statistically assess that difference. In the study comparing use of standard polarity with reverse polarity using both monophasic and biphasic waveforms, 84 percent of patients with standard polarity and 78 percent with 197 reverse polarity reverted to sinus rhythm (statistical test not provided). In the study comparing steel paddles with adhesive pads using both monophasic and biphasic waveforms, 96 percent of patients with the steel paddles compared with 88 percent of patients with the adhesive patches had restoration of sinus rhythm immediately following the 176 cardioversion (p=0. Cardioversion success rate was 100 percent in the biphasic shock group with paddle electrodes (56/56 patients) but 96 percent (46/48 patients) when patches were used (p=0. Maintenance of Sinus Rhythm Biphasic Versus Monophasic Waveforms In the study that assessed maintenance of sinus rhythm at 1 month following electrical 194 cardioversion, there was no statistically significant difference between biphasic and monophasic waveforms in these patients with persistent AF (60% vs. Recurrence of Atrial Fibrillation Biphasic Versus Monophasic Waveforms In assessing early recurrence of AF there was no statistically significant difference between the biphasic and monophasic waveform in the 1 study that assessed this outcome in patients with 203 persistent AF (8. Results in Specific Subgroups of Interest Thirteen (62%) of the 21 studies that compared different methods of external electrical cardioversion included only patients with persistent AF (2 of 9 studies comparing biphasic with 194,203 monophasic waveforms, all 4 studies comparing anterolateral vs. As expected, methods of external electrical cardioversion would be most relevant to patients with persistent AF, and therefore, the majority of studies focused primarily on this subgroup of interest. The results of these studies therefore may not be applicable to patients with permanent AF and are potentially applicable only to subsets of patients with paroxysmal AF. Of the eight studies that were not categorized as including only patients with 173,174,179,182,184,196,201 200 persistent AF, seven did not provide information on type of AF, and one had seven percent of patients with paroxysmal AF; the proportion of patients with other types of AF were not reported. Therefore, comparisons in results by type of AF could not be made. The general objective of these studies was to determine if drug pretreatment improves the outcome of external electrical cardioversion. A total of 329 patients were included 178,195,199 in these studies; 3 studies included only patients with persistent AF. One study was rated 178 195,199 205 as good quality, two were fair quality, and one was poor quality. All four studies were 178,195,205 conducted in Europe, and three were single-center; the number of sites was not reported 199 in the fourth study. In the two studies using verapamil, verapamil was given 3 days before and 199,205 3 days after electrical cardioversion. Ibutilide was given about 20 minutes before electrical 195 cardioversion, and metoprolol was titrated over an unspecified time period prior to electrical 178 cardioversion. Placebo was administered to patients in the electrical cardioversion arm only in 178 the study that assessed metoprolol pretreatment. Mean age of patients ranged from 60–69 years in the drug-enhanced arms and from 60–68 years in the electrical cardioversion only arms. Restoration of sinus rhythm 178,195 immediately after electrical cardioversion was reported in two studies. Maintenance of 178,199 sinus rhythm 1 week after electrical cardioversion was assessed in two studies, and 205 recurrence of AF at 1 week was reported in one poor-quality study. Restoration of Sinus Rhythm Two of the four studies included a measure of restoration of sinus rhythm following the electrical cardioversion procedure. Both studies included only patients with persistent AF. One compared external electrical cardioversion with ibutilide pretreatment versus electrical 195 cardioversion without ibutilide pretreatment. In this study 100 percent of patients in both groups had sinus rhythm restored immediately after electrical cardioversion. In a second study, restoration of sinus rhythm immediately after cardioversion was compared among patients receiving metoprolol pretreatment and patients receiving placebo pretreatment. Ninety-five percent of patients with metoprolol pretreatment converted to sinus rhythm compared with 93 percent of patients without metoprolol pretreatment (no p-value reported; moderate strength of evidence). Maintenance of Sinus Rhythm Two of the four studies assessed maintenance of sinus rhythm at 1 week following external electrical cardioversion. In one study comparing metoprolol pretreatment with no 178 pretreatment, a greater proportion of patients with metoprolol pretreatment maintained sinus rhythm at 1 week than did patients without metoprolol pretreatment (55% vs. Two patients in the metoprolol group developed bradycardia, and 10 percent and 9 percent, respectively, developed vertigo or dizziness in the metoprolol and no metoprolol groups. In the 199 second study, verapamil pretreatment was compared with no verapamil pretreatment in 23 patients with persistent AF. Eight of 9 patients (89%) receiving verapamil pretreatment maintained sinus rhythm at 1 week compared with 6 of 14 patients (43%) not receiving verapamil pretreatment (p=0. There was significant benefit for patients given verapamil or metoprolol pretreatment (moderate strength of evidence). In this study 3 percent of patients with verapamil pretreatment compared with 11 percent without verapamil pretreatment had recurrent AF within 1 week following cardioversion (p=0. Results in Specific Subgroups of Interest As described above, three of the four studies included patients with only persistent AF. As with the overall results, no definitive conclusions can be drawn for this subgroup of interest because of the small number of patients and different drug treatments used in the studies. Other specific subgroups of interest were not explored within the included studies. Comparison of Drugs for Pharmacologic Cardioversion Overview Seventeen studies including 2,455 patients compared 2 or more rate- or rhythm-control drugs 140,144,145,147,149,170,177,180,181,188-193,204,206 and assessed conversion of AF to sinus rhythm. Six studies 145,147,180,189,190,206 140,144,149,170,177,188,191-193 were multicenter, nine were single-center, and in two the 181,204 number of sites was not reported. Twelve studies were conducted in 140,144,145,147,170,177,188,191-193,204,206 149,190 181 Europe, two in Australia/New Zealand, one in the UK, 180,189 140,170,177,180,181 and two in the United States.
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