Diaphragm Pacing with a Quadripolar Phrenic Nerve Electrode: An International Study

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 ± 1.0 years among children and 2.2 ± 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0–4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication- free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94 % of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.     

Better late than never? An evaluation of community nursing services for children in the UK

• ? The development of community nursing services for children in the UK was first suggested by Platt in 1959; until recently, however, such services have been rare and children have spent many unnecessary and potentially traumatic days in hospital.
• ? This paper considers the development of community nursing services for children in the UK.
• ? It identifies factors which have promoted the growth of these schemes, and examines the effectiveness of services from professional, managerial and economic perspectives.
• ? The viewpoint of the consumer – the child and family themselves – is also considered.

     

Intravascular Lead Extraction Using Locking Stylets and Sheaths

BYRD, C.L., ET AL.: Intravascular Lead Extraction Using Locking Stylets and Sheaths. Chronic lead extraction using intravascular countertraction techniques was studied in patients with over 65 different lead models including passive and active fixation devices. Indications for removal of 115 leads implanted 5 days to 264 months (mean 58 months) in 62 patients (mean 65 years) included septicemia, subcutaneous tissue infection, preerosion, free-floating lead, lead trapped in valve, too many leads, pain, and vein thrombosis. The superior vena cava (SVC) approach was attempted in 101 leads and was successful in 82 attempts (71% of total leads). The inferior vena cava (IVC) approach via the femoral vein was required to extract 14 (12%) leads inaccessible to the SVC approach and the 19 leads that failed the SVC approach (29% of total leads). The SVC procedure includes a sized stylet locked at the tip and telescoping sheaths advanced over the lead to the heart. An IVC procedure includes placement of a 16 F sheath workstation via a femoral vein into the right atrium. A deflection catheter and Dotter snare in an 11 F sheath were advanced through the workstation into the right atrium. The lead was maneuvered into position, snared, and pulled into the workstation. For both the SVC and IVC approaches, the leads were removed by applying traction on the lead and countertraction with the sheaths. In experienced hands, these techniques have proven safe and effective for removing chronic transvenous leads.     

Dexmedetomidine pharmacokinetics in pediatric intensive care – a pooled analysis

Background: Published dexmedetomidine pharmacokinetic studies in children are limited by participant numbers and restricted pathology. Pooling the available studies allows investigation of covariate effects. Methods: Data from four studies investigating dexmedetomidine pharmacokinetics after i.v. administration (n = 95) were combined to undertake a population pharmacokinetic analysis of dexmedetomidine time–concentration profiles (730 observations) using nonlinear mixed effects modeling (NONMEM). Estimates were standardized to a 70‐kg adult using allometric size models. Results: Children had a mean age of 3.8 (median 3 years, range 1 week–14 years) and weight of 16.0 kg (median 13.3 kg, range 3.1–58.9 kg). Population parameter estimates (between subject variability) for a two‐compartment model were clearance (CL) 42.1 (CV 30.9%) l·h^?1·70 kg^?1, central volume of distribution (V1) 56.3 (61.3%) l·70 kg^?1, inter‐compartment clearance (Q) 78.3 (37.0%) l·h^?1·70 kg^?1 and peripheral volume of distribution (V2) 69.0 (47.0%) l·70 kg^?1. Clearance maturation with age was described using the Hill equation. Clearance increases from 18.2 l·h^?1·70 kg^?1 at birth in a term neonate to reach 84.5% of the mature value by 1 year of age. Children given infusion after cardiac surgery had 27% reduced clearance compared to a population given bolus dose. Simulation of published infusion rates that provide adequate sedation for intensive care patients found a target therapeutic concentration of between 0.4 and 0.8 μg·l^?1. Conclusions: The sedation target concentration is similar to that described for adults. Immature clearance in the first year of life and a higher clearance (when expressed as l·h^?1·kg^?1) in small children dictate infusion rates that change with age. Extrapolation of dose from children given infusion in intensive care after cardiac surgery may not be applicable to those sedated for noninvasive procedures out of intensive care.     

Endovascular Abdominal Aortic Aneurysm Repair by Interventional Cardiologists—A Community‐Based Experience

Introduction: Endovascular repair of abdominal aortic aneurysm (AAA) is a relatively recent technology. In comparison to the conventional open surgical treatment for AAA, endovascular AAA repair (EVAR) combines a less‐invasive approach with lower morbidity and mortality. There have been few studies regarding the performance of this procedure in a community‐based setting. We report our experience of EVAR performed primarily by interventional cardiologists in a community hospital. Methods: In our community hospital setting, between September 2005 and November 2007, we included all patients who underwent EVAR by interventional cardiologists, with available on‐site vascular surgical support. Clinical and serial computed angiographic imaging outcomes were followed by a retrospective chart review. Data collection tools included demographic and clinical characteristics, anatomical aneurysm features, length of stay, peri‐ and postprocedural complications, and mortality. Results: A total of 71 consecutive patients had EVAR attempted. The endovascular stent placement was successful in 67 (93%) patients. Thirty‐day mortality in this study was 1 of 71 (1.4%). All four procedural failures and the single periprocedural mortality occurred in women. Mean follow‐up was 12 months. There were a total of six mortalities and among these four were women (P ≤ 0.001); however, multivariate analysis revealed loss of significant difference in mortality (P = 0.16). Major complications following EVAR were noted in 10 of 71 (14%) patients. Conclusion: EVAR can be successfully performed by experienced interventional cardiologists with vascular surgical support in a community‐based setting. In our experience, there is acceptable rate of complications and mortality in a carefully selected patient population. (J Interven Cardiol 2010;23:485–490)     

Neonatal pulmonary hypertension prevents reorganisation of the pulmonary arterial smooth muscle cytoskeleton after birth

The pulmonary arterial smooth muscle cell (SMC) cytoskeleton was studied in tissue from 36 piglets aged from within 5 min of birth to 21 d of age, and in 8 adults. An additional 16 piglets were made pulmonary hypertensive by exposure to hypobaric hypoxia (50.8 kPa) for 3 d. In conduit intrapulmonary elastic arteries α, β and γ actin, the 204, 200 and 196 kDa myosin heavy chain (MHC) isoforms and vinculin were localised by immunohistochemistry. The total actin content, the proportion of monomeric to filamentous α and γ actin and changes in the proportions of the MHC isoforms were determined biochemically. Dividing SMCs were localised and quantified using Ki-67. We found a transient reduction in immunohistochemical expression of γ actin, 204 kDa MHC isoform and vinculin at 3 and 6 d in the inner media, associated with a transient increase in Ki-67 labelling. The actin content also decreased at 3 and 6 d ( P < 0.05), but there was a postnatal, permanent increase in monomeric actin, first the α then the γ isoform. The relative proportions of the MHC isoforms did not change between birth and adulthood in elastic pulmonary arteries but in muscular arteries the 200 kDa isoform increased between 14 d and adulthood. Pulmonary hypertension prevented both the immunohistochemical changes and the postnatal burst of SMC replication and prevented the transient postnatal reduction in actin content. These findings suggest that rapid remodelling of the actin cytoskeleton is an essential prerequisite of a normal postnatal fall in pulmonary vascular resistance.     

Asymmetric sensorineural hearing loss in a community-based population

Asymmetric sensorineural hearing loss (ASNHL) is fairly common, but it can be an indication of retrocochlear pathology. The incidence of acoustic neuroma (AN) has been estimated at 1/100,000; however, the incidence of AN in patients with ASNHL is unknown. The limitation of health care resources challenges otolaryngologists to develop reasonable cost-containment guidelines for the evaluation of patients with ASNHL for the presence of retrocochlear pathology. A 5-year (1990 to 1994) retrospective study of all patients with ASNHL who were evaluated in a community-based general otolaryngology practice was performed. Demographic, historic, and audiologic data and results from ABRs and radiologic studies were summarized. ASNHL was present in 325 patients. Auditory brain stem response tests were performed in 179 patients (55%), and 92% (164 of 179) were normal. Patients with abnormal or inconclusive auditory brain stem responses and patients with severe SNHL were evaluated with radiologic studies (46 patients). Among the 193 patients who had diagnostic studies, 4 were found to have ANs, for a prevalence of 2.1%. The charge of diagnosis per AN was more than $41,000. In summary, a small percentage of patients with ASNHL have retrocochlear pathology, and the charge of diagnosis per AN can be excessive. A cost-containment approach for the evaluation and management of patients with ASNHL is proposed.     

Top-Ranked Schools of Nursing: Network of Scholars

The Top-Ranked Schools of Nursing (TRSN) study was a nationwide investigation to delineate a composite of elements that characterizes a top-ranked school. Research was identified as one of those significant elements. The influence and scope of research in a TRSN study is described as are the ways in which these endeavors are pursued and supported. These findings will be of benefit to those interested in promoting and improving nursing scholarship.     

The Valve of Vieussens: An Important Cause of Difficulty in Advancing Catheters into the Cardiac Veins

INTRODUCTION: The coronary sinus and cardiac veins are useful conduits for the passage of electrode catheters for mapping the origin of cardiac arrhythmias. However, sometimes it is difficult to advance catheters an adequate distance into the cardiac veins. The aim of this study was to determine the reasons for this. METHODS AND RESULTS: In 50 cadaveric hearts, a deflectable 7-French electrode catheter was passed from the right atrium into the coronary sinus and advanced to the anterior interventricular portion of the great cardiac vein (GCV). Causes of obstruction were determined. The catheter was obstructed by the valve of Vieussens in 23 of 50 hearts (46%). Once the valve was negotiated, obstruction was caused by an acute bend in the GCV in 28 of 50 hearts (56%). Clinical studies were undertaken in 10 patients in whom electrode catheters could not be advanced as far as required. Using contrast venography, the most frequent cause of obstruction was determined to be the valve of Vieussens in 8 of 10 cases (80%). An acute bend in the GCV caused obstruction in 2 cases (20%). CONCLUSIONS: The valve of Vieussens is a frequent cause of obstruction to passage of a catheter in postmortem and in vivo studies. An acute bend in the vein, with or without lodgment in a tributary, is the other common cause. In adults, venous luminal diameter is not a cause of obstruction to the passage of a 7-French catheter in the coronary sinus or proximal GCV.     

Lessons from community participation in health programmes

Although primary health care emphasizes community participationand many health care programmes attempt to develop participation,good analysis of these developments is still rare. This paper,based on a review of about 200 case studies, examines some ofthe lessons for planners which are emerging from experiencesof the last decade. These lessons focus on the problems of definingthe term ‘community participation’, of gaining andsustaining broad-based community participation, of failing torecognize the political implications of the concept and of attemptingto develop a management model of community participation forhealth. Based on these lessons, a planning framework is suggestedthat seeks individual programme answers to three questions:‘Why participation?’, ‘Who participates?’,‘How do they participate?’. The answers to thesequestions will help to define a programme's objectives and tomonitor and evaluate its development.