A Psychiatric Nurse's Perspective: Helping Patients Undergo Repetitive Transcranial Magnetic Stimulation (rTMS) for Depression.

With the October 2008 Food and Drug Administration approval of repetitive transcranial magnetic stimulation (rTMS) for depression treatment, the establishment and administration of rTMS clinical treatment programs are critically important and emerging areas for psychiatric nursing leadership. There is growing recognition that many patients are unable to tolerate antidepressant medications and require alternative antidepressant treatment approaches. The enormous growth in the field of brain stimulation creates exciting new therapeutic options for patients with treatment-resistant depression. As with any clinical breakthrough, new treatments offer exciting possibilities but also require growth in psychiatric nursing knowledge, different practice competencies, and new ways of organizing care. This article discusses current practice guidelines, psychiatric nursing qualifications, and essential details about developing an rTMS clinical service. This is the first article to describe the role of a psychiatric nurse establishing a clinical rTMS service, administering rTMS, and helping patients undergo the treatment. The authors share the progress made and the lessons learned.

The spatial-temporal redistribution of pulmonary blood flow with postnatal growth.

The pulmonary vascular tree undergoes remarkable postnatal development and remodeling. While a number of studies have characterized longitudinal changes in vascular function with growth, none have explored regional patterns of vascular remodeling. We therefore studied six neonatal pigs to see how regional blood flow changes with growth. We selected pigs because of their rapid growth and their similarities to human development with respect to the pulmonary vascular tree. Fluorescent microspheres of varying colors were injected into the pulmonary circulation to mark regional blood on days 3, 12, 27, 43, and 71 after birth. The animals were awake and in the prone posture for all injections. The lungs were subsequently removed, air dried, and sectioned into approximately 2-cm(3) pieces. Flow on each injection day was determined for each piece. Despite the increase in the hydrostatic gradient in the lung with growth, there was a strong correlation between blood flow to the same lung piece when compared on days 3 and 71 (0.73 +/- 0.12). Although a dorsal-ventral gradient of perfusion did not exist on day 3, blood flow increased more in the dorsal region by day 12 and then gradually became more uniform by day 71. Although most of the lung pieces did not show any discernable pattern of blood flow redistribution, there were spatial patterns of blood flow redistribution that were similar across animals. Our findings suggest that local mechanisms, shared across animals, guide regional changes in vascular resistance or vasoregulation during postnatal development. In the pig, these mechanisms act to produce more uniform flow in the normal posture for an ambulating quadruped. The stimuli for these changes have not yet been identified.

Hypoxia has a greater effect than exercise on the redistribution of pulmonary blood flow in swine.

Strenuous exercise combined with hypoxia is implicated in the development of high-altitude pulmonary edema (HAPE), which is believed to result from rupture of pulmonary capillaries secondary to high vascular pressures. The relative importance of hypoxia and exercise in altering the distribution of pulmonary blood flow (PBF) is unknown. Six chronically catheterized specific pathogen-free Yorkshire hybrid pigs (25.5 +/- 0.7 kg, means +/- SD) underwent incremental treadmill exercise tests in normoxia (Fi(O(2)) = 0.21) and hypoxia (Fi(O(2)) = 0.125, balanced order), consisting of 5 min at 30, 60, and 90% of the previously determined Vo(2max). At steady state (~4 min), metabolic and cardiac output data were collected and fluorescent microspheres were injected over approximately 30 s. Later the fluorescent intensity of each color in each 2-cm(3) lung piece was determined and regional perfusion was calculated from the weight-normalized fluorescence. Both hypoxia and exercise shifted PBF away from the ventral cranial lung regions toward the dorsal caudal regions of the lung, but hypoxia caused a greater dorsal caudal shift in PBF at rest than did near-maximal exercise in normoxia. The variance in PBF due to hypoxia, exercise, and vascular structure was 16 +/- 4.2, 4.0 +/- 4.4, and 59.4 +/- 11.4%, respectively, and the interaction between hypoxia and exercise represented 12 +/- 6.5%. This observation implies that there is already a maximal shift with in PBF with hypoxia in the dorsal-caudal regions in pigs that cannot be exceeded with the addition of exercise. However, exercise greatly increases the pulmonary arterial pressures and therefore the risk of capillary rupture in high flow regions.

Intravital microscopic observations of 15-microm microspheres lodging in the pulmonary microcirculation.

Vascular infusions of 15-microm-diameter microspheres are used to study pulmonary blood flow distribution. The sites of microsphere lodging and their effects on microvascular perfusion are debated but unknown. Using intravital microscopy of the subpleural surface of rat lungs, we directly observed deposition of fluorescent microspheres. In a pump-perfused lung model, approximately 0.5 million microspheres were infused over 30 s into the pulmonary artery of seven rats. Microsphere lodging was analyzed for the location in the microvasculature and the effect on local flow after lodging. On average, we observed 3.2 microspheres per 160 alveolar facets. The microspheres always entered the arterioles as singlets and lodged at the inlets to capillaries, either in alveolar corner vessels or small arterioles. In all cases, blood flow continued either around the microspheres or into the capillaries via adjacent pathways. We conclude that 15-microm-diameter microspheres, in doses in excess of those used in typical studies, have no significant impact on pulmonary capillary blood flow distribution.

Structure and size of bronchopulmonary anastomoses in sheep lung.

The distribution and drainage of bronchial arterial blood flow are complex. We used two different methods to study the bronchial-pulmonary anastomoses in sheep lung. Initially, we injected two different sizes of fluorescent microspheres (15 and 100 microm diameter) into the bronchial artery and histologically determined where the different-size microspheres were entrapped in the lung. In a second series of animals, we injected Microfil into the bronchial artery to observe the anastomotic vessels. The microsphere data confirmed the existence of bronchial-to-pulmonary anastomoses. No microspheres were found in the systemic organs (heart and kidney), confirming the absence of large bronchial artery-to-pulmonary vein anastomoses. Unexpectedly, proportionately more large microspheres (100 microm) lodged in the alveolar parenchyma when compared to 15 microm microspheres. This suggests that there are many more small bronchial (< 100 microm) arterioles feeding the airway mucosa than the larger anastomotic vessels feeding into the parenchyma. In the Microfil cast lungs, we observed four types of anastomotic vessels: bronchial arteries/arterioles that anastomose with pulmonary arteries/arterioles that accompany airways; bronchial arterioles that anastomose directly with parenchymal (and eventually alveolar) vessels; bronchial arterioles that anastomose with blood vessels that do not accompany airways; and bronchial arterioles that anastomose with bronchial veins. Based on our in vivo microsphere data, the vessels that do not accompany the airways are most likely bronchial venules, not pulmonary venules.

Soluble gas exchange in the pulmonary airways of sheep.

We studied the airway gas exchange properties of five inert gases with different blood solubilities in the lungs of anesthetized sheep. Animals were ventilated through a bifurcated endobronchial tube to allow independent ventilation and collection of exhaled gases from each lung. An aortic pouch at the origin of the bronchial artery was created to control perfusion and enable infusion of a solution of inert gases into the bronchial circulation. Occlusion of the left pulmonary artery prevented pulmonary perfusion of that lung so that gas exchange occurred predominantly via the bronchial circulation. Excretion from the bronchial circulation (defined as the partial pressure of gas in exhaled gas divided by the partial pressure of gas in bronchial arterial blood) increased with increasing gas solubility (ranging from a mean of 4.2 x 10(-5) for SF6 to 4.8 x 10(-2) for ether) and increasing bronchial blood flow. Excretion was inversely affected by molecular weight (MW), demonstrating a dependence on diffusion. Excretions of the higher MW gases, halothane (MW = 194) and SF6 (MW = 146), were depressed relative to excretion of the lower MW gases ethane, cyclopropane, and ether (MW = 30, 42, 74, respectively). All results were consistent with previous studies of gas exchange in the isolated in situ trachea.

Axial and radial distribution of the bronchial vasculature in sheep.

A morphometric analysis was made on the bronchial vasculature of intrapulmonary airways in sheep lungs. This study provides the parameters to calculate the quantity of soluble gas diffusion between the vasculature and airways for use in a mathematical model describing heat and mass exchange in the lungs. To achieve these results, the lungs of four adult sheep (30-36 kg.) were excised, fixed, dissected and microtomed to obtain airway cross-sections for measurement. Blood vessel size and airway proximity was measured using a microscope interfaced with a computer. Distance from airway lumen to most airway vessels ranged from 30 to 270 microm. It was found that the bronchial vessels surrounding intraparenchymal airways can be described by a right-skewed distribution. Most importantly, a practical description of the bronchial capillary size and airway proximity as a function of airway diameter was found using a weighed average. This analysis facilitates calculation of soluble gas flux from the bronchial vasculature to the airway for use in a mathematical model.

Validation of the Nonin 8600V Pulse Oximeter for heart rate and oxygen saturation measurements in rats.

This report validates the use and limitations of the Nonin Pulse Oximeter for measuring heart rate and oxygen saturation in rats. Eight anesthetized Sprague-Dawley rats were intubated and catheterized. Oxygen saturation was directly measured from arterial blood by using a Radiometer OSM3 Hemoximeter adjusted for rat blood as well as indirectly by using the Nonin Pulse Oximeter. Oxygen saturation was changed by varying the level of inhaled oxygen. Heart rate was measured in two ways: 1) by using the signal from the Nonin Pulse Oximeter and 2) by counting the pressure pulses from the transduced blood pressure. There was excellent agreement between heart rate values measured by the Nonin Pulse Oximeter and that measured by counting the pulses from the arterial blood pressure recording. The Nonin Pulse Oximeter underestimated oxygen saturations by about 3% to 5% compared to the Hemoximeter. Overall, the pulse oximeter reflected important trends in oxygen saturations, making it a useful tool for laboratory animal medicine.

Quantifying the genetic influence on mammalian vascular tree structure.

The ubiquity of fractal vascular trees throughout the plant and animal kingdoms is postulated to be due to evolutionary advantages conferred through efficient distribution of nutrients to multicellular organisms. The implicit, and untested, assertion in this theory is that the geometry of vascular trees is heritable. Because vascular trees are constructed through the iterative use of signaling pathways modified by local factors at each step of the branching process, we sought to investigate how genetic and nongenetic influences are balanced to create vascular trees and the regional distribution of nutrients through them. We studied the spatial distribution of organ blood flow in armadillos because they have genetically identical littermates, allowing us to quantify the genetic influence. We determined that the regional distribution of blood flow is strongly correlated between littermates (r(2) = 0.56) and less correlated between unrelated animals (r(2) = 0.36). Using an ANOVA model, we estimate that 67% of the regional variability in organ blood flow is genetically controlled. We also used fractal analysis to characterize the distribution of organ blood flow and found shared patterns within the lungs and hearts of related animals, suggesting common control over the vascular development of these two organs. We conclude that the geometries of fractal vascular trees are heritable and could be selected through evolutionary pressures. Furthermore, considerable postgenetic modifications may allow vascular trees to adapt to local factors and provide a flexibility that would not be possible in a rigid system.

Qualitative assessment of risk for monkeypox associated with domestic trade in certain animal species, United States.

In 2003, US officials identified several human monkeypox cases and traced the virus exposure to infected captive prairie dogs. The virus was likely introduced through a shipment of imported African rodents, which were kept with other mammals, including prairie dogs, in a pet distribution facility in the Midwest. To prevent the further introduction and spread of the virus, federal agencies restricted the importation of African rodents and restricted the domestic trade or movement of prairie dogs and certain other rodents. In this qualitative assessment of the risk for monkeypox associated with the 2003 outbreak, we conclude that the probability of further human infection is low; the risk is further mitigated by rodent import restrictions. Were this zoonotic disease to become established domestically, the public health effects could be substantial.

Should the Centers for Disease Control and Prevention's childhood lead poisoning intervention level be lowered?

The US Centers for Disease Control and Prevention (CDC) in 1991 chose 10 micro g/dL as an initial screening level for lead in children's blood. Current data on health risks and intervention options do not support generally lowering that level, but federal lead poisoning prevention efforts can be improved by revising the follow-up testing schedule for infants aged 1 year or less with blood lead levels of 5 micro g/dL or higher; universal education about lead exposure risks; universal administration of improved, locally validated risk-screening questionnaires; enhanced compliance with targeted screening recommendations and federal health program requirements; and development by regulatory agencies of primary prevention criteria that do not use the CDC's intervention level as a target "safe" lead exposure.

Prevalence of blood lead levels >or= 5 micro g/dL among US children 1 to 5 years of age and socioeconomic and demographic factors associated with blood of lead levels 5 to 10 micro g/dL, Third National Health and Nutrition Examination Survey, 1988-1994.

OBJECTIVES: As part of an investigation into the impact of a potential revision in federal childhood lead poisoning prevention policy that would result in screening children for blood lead levels (BLLs) >or=5 micro g/dL rather than the current 10 micro g/dL, we analyzed the most recent available, nationally representative data to identify prevalence of BLLs >or=5 micro g/dL and socioeconomic and demographic characteristics of 1- to 5-year-old children with BLLs >or=5 but <10 micro g/dL. METHODS: We performed statistical analyses on data from the Third National Health and Nutrition Examination Survey (NHANES III) (1988-1994) to describe trends in BLLs >or=5 micro g/dL overall and among subpopulations of children <6 years old and to compare risk factors for falling within 1 of 3 groups of children (those with BLLs >or=5 but <10 micro g/dL; >or=10 but <20 micro g/dL; and >or=20 micro g/dL) using the group reported as 0.7 to <5 micro g/dL as the referent. RESULTS: Overall prevalence of BLLs >or=5 micro g/dL among 1- to 5-year-old children was 25.6%, although most (76%) of these children had BLLs <10 micro g/dL. Children with BLLs >or=5 micro g/dL included 46.8% of non-Hispanic black children, 27.9% of Mexican American children, and 18.7% of non-Hispanic white children; 42.5% of children in housing built before 1946, 38.9% of children in housing built between 1946 and 1973, and 14.1% of children in housing built after 1973 had BLLs >or=5 micro g/dL. Compared with non-Hispanic white children, non-Hispanic black children were 3 times more likely to have a BLL >or=5 but <10 micro g/dL, 7 times more likely to have a BLL of 10-20 micro g/dL, and 13.5 times more likely to have a BLL >or=20 micro g/dL. Similar increases in the association between risk factor and BLL were seen with respect to other known risk factors including age of housing, region of the country, and poverty. CONCLUSIONS: The high prevalence of BLLs >or=5 micro g/dL overall and within US subpopulations will be an important variable in any change in screening and intervention criteria. However, most children with BLLs >or=5 micro g/dL are below the current intervention level of 10 micro g/dL. Exposure to lead from multiple sources is suggested by the prevalence of BLLs >or=5 micro g/dL but <10 micro g/dL among children with uncertain risk factors. The probable presence of one or more known risk factors for childhood lead poisoning increases as BLL increases.

Municipal heat wave response plans.

Approximately 400 people die from extreme heat each year in the United States, and the risk of heat waves may increase as a result of global climate change. Despite the risk of heat-related morbidity and mortality, many cities lack written heat response plans. In a review of plans from 18 cities at risk for heat-related mortality, we found that many cities had inadequate or no heat response plans. This is an important area for further investigation and government attention.