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Failure Rate (failure + rate)
Kinds of Failure Rate Terms modified by Failure Rate Selected AbstractsA simple approach for optimum channel reservation for hand-over calls in cellular systemsINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2006Mohamed Laith In cellular mobile communication systems, while an active subscriber is moving from one cell to another, the service of his call needs to be handed over to the base station of the new cell. In such a case, cutting the service, due to all channels being busy at the new base station, would be more annoying to subscribers than normal congestion at the first initiation of calls. This paper is concerned with providing a simple approach for choosing the optimum set of channels that need to be reserved for hand-over calls, while maintaining an acceptable overall system performance. The approach evaluates channel reservation at the cell level, taking into account the offered traffic, that is both the newly initiated original traffic and the hand-over traffic. The approach produces a simple mathematical solution based on Erlang-B formula. It uses the concept of ,Combined Failure Rate' to evaluate the required reservation. The approach is supported by a simulation study that verifies its validity. Applications of the approach to illustrate its use are also presented.,Copyright © 2006 John Wiley & Sons, Ltd. [source] Occipital Nerve Blocks: Effect of Symptomatic MedicationHEADACHE, Issue 10 2009Headache Type on Failure Rate, Overuse Objective., To explore the effect of symptomatic medication overuse (SMO) and headache type on occipital nerve block (ONB) efficacy. Methods., We conducted a chart review of all of the ONBs performed in our clinic over a 2-year period. Results., Of 108 ONBs with follow-up data, ONB failed in 22% of injections overall. Of the other 78%, the mean decrease in head pain was 83%, and the benefit lasted a mean of 6.6 weeks. Failure rate without SMO was 16% overall, and with SMO was 44% overall (P < .000). In those who did respond, overall magnitude and duration of response did not differ between those with and those without SMO. Without SMO, ONB failure rate was 0% for postconcussive syndrome, 14% for occipital neuralgia, 11% for non-intractable migraine, and 39% for intractable migraine. With SMO, failure rate increased by 24% (P = .14) in occipital neuralgia, by 36% (P = .08) for all migraine, and by 52% (P = .04) for non-intractable migraine. Conclusions., SMO tripled the risk of ONB failure, possibly because medication overuse headache does not respond to ONB. SMO increased ONB failure rate more in migraineurs than in those with occipital neuralgia, possibly because migraineurs are particularly susceptible to medication overuse headache. This effect was much more pronounced in non-intractable migraineurs than in intractable migraineurs. [source] Early nasal intermittent positive pressure ventilation versus continuous positive airway pressure for respiratory distress syndromeACTA PAEDIATRICA, Issue 9 2009M Sai Sunil Kishore Abstract Aim:, To determine whether early nasal intermittent positive pressure ventilation (NIPPV), in comparison to early continuous positive airway pressure (CPAP), can reduce the need for intubation and mechanical ventilation in preterm neonates with suspected respiratory distress syndrome (RDS). Methods:, In this stratified open-label randomized controlled trial, neonates (28,34 weeks gestation) with respiratory distress within 6 h of birth and Downe's score , 4 were eligible. Subjects were randomly allocated to ,early-NIPPV' or ,early-CPAP' after stratifying for gestation (28,30 weeks, 31,34 weeks) and surfactant use. Primary outcome was failure of the allocated mode within 48 h. Results:, Seventy-six neonates were enrolled (37 in ,early-NIPPV' and 39 in ,early-CPAP' groups). Failure rate was less with ,early-NIPPV' versus ,early-CPAP'[13.5% vs. 35.9%, respectively, RR 0.38 (95% CI 0.15,0.89), p = 0.024]. Similarly, need for intubation and mechanical ventilation by 7 days (18.9% vs. 41%, p = 0.036) was less with NIPPV. Failure rate with NIPPV was less in the subgroups of subjects born at 28,30 weeks (p = 0.023) and who did not receive surfactant (p = 0.018). Conclusion:, Among preterm infants with suspected RDS, early use of NIPPV reduces the need for intubation and mechanical ventilation compared to CPAP. [source] A randomised controlled trial of two instruments for vacuum-assisted delivery (Vacca Re-Usable OmniCup and the Bird anterior and posterior cups) to compare failure rates, safety and use effectivenessAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 3 2010Glen D.L. MOLA Background:, Most previous trials of vacuum-assisted delivery have been in settings with high rates of instrumental vaginal delivery (8,12%) and high rates of failure to deliver with the intended instrument (20,30%). Over the past 20 years, vacuum-assisted delivery rates at the Port Moresby General Hospital have been 3,4% with failure rates of <3%. Objective:, The objective is to compare the failure rates of two vacuum extractor instruments, the Vacca Re-Usable Omnicup and the Bird Vacuum delivery system (anterior and posterior cups). Setting:, Port Moresby General national referral and teaching Hospital (PMGH), Papua New Guinea. Population:, Two hundred consecutive women requiring assisted delivery, June,December, 2007. Methods:, When a woman required an assisted delivery, she was randomised into either the Vacca Re-Usable Omnicup (Clinical Innovations Inc.) or Bird anterior or posterior metal cup (depending upon the position of the vertex). One hundred women were randomised to each vacuum device. Statistical analysis was on ,an intention-to-treat' basis. Main outcome measures:, The main outcome measure was the successful completion of the delivery with the allocated instrument. Secondary outcomes were maternal trauma (episiotomy and trauma to the maternal genital tract), significant scalp trauma (sub-galeal haemorrhage or serious abrasion) and fetal and neonatal outcomes (Apgar score less than seven at 5 minutes, days spent in the Special Care Nursery and neonatal death). Results:, Failure rates for both Omnicup (2/100) and Bird metal cups (6/100) were not statistically different (RR 1.05, 95% CI 0.99,1.12; P = 0.17). Rates of maternal trauma and fetal scalp trauma were similar in both groups. Conclusion:, Both the Vacca re-useable Omnicup and the Bird metal cups are very effective instruments to achieve successful assisted delivery and equally so. Failures and problems were associated with not applying the vacuum cup to the flexion point on the fetal scalp and the mechanical faults with vacuum equipment devices. [source] A comparative evaluation of digital imaging, retinal photography and optometrist examination in screening for diabetic retinopathyDIABETIC MEDICINE, Issue 7 2003J. A. Olson Abstract Aims To compare the respective performances of digital retinal imaging, fundus photography and slit-lamp biomicroscopy performed by trained optometrists, in screening for diabetic retinopathy. To assess the potential contribution of automated digital image analysis to a screening programme. Methods A group of 586 patients recruited from a diabetic clinic underwent three or four mydriatic screening methods for retinal examination. The respective performances of digital imaging (n = 586; graded manually), colour slides (n = 586; graded manually), and slit-lamp examination by specially trained optometrists (n = 485), were evaluated against a reference standard of slit-lamp biomicroscopy by ophthalmologists with a special interest in medical retina. The performance of automated grading of the digital images by computer was also assessed. Results Slit-lamp examination by optometrists for referable diabetic retinopathy achieved a sensitivity of 73% (52,88) and a specificity of 90% (87,93). Using two-field imaging, manual grading of red-free digital images achieved a sensitivity of 93% (82,98) and a specificity of 87% (84,90), and for colour slides, a sensitivity of 96% (87,100) and a specificity of 89% (86,91). Almost identical results were achieved for both methods with single macular field imaging. Digital imaging had a lower technical failure rate (4.4% of patients) than colour slide photography (11.9%). Applying an automated grading protocol to the digital images detected any retinopathy, with a sensitivity of 83% (77,89) and a specificity of 71% (66,75) and diabetic macular oedema with a sensitivity of 76% (53,92) and a specificity of 85% (82,88). Conclusions Both manual grading methods produced similar results whether using a one- or two-field protocol. Technical failures rates, and hence need for recall, were lower with digital imaging. One-field grading of fundus photographs appeared to be as effective as two-field. The optometrists achieved the lowest sensitivities but reported no technical failures. Automated grading of retinal images can improve efficiency of resource utilization in diabetic retinopathy screening. Diabet. Med. 20, 528,534 (2003) [source] Temporary self-expanding metallic stents and pneumatic dilation for the treatment of achalasia: a prospective study with a long-term follow-upDISEASES OF THE ESOPHAGUS, Issue 5 2010Y.-D. Li SUMMARY The present study compares the efficacy of a self-expanding metallic stent (SEMS, diameter of 30 mm) and pneumatic dilation for the long-term clinical treatment of achalasia. A total of 155 patients diagnosed with achalasia were allocated for pneumatic dilation (n= 80, group A) or a temporary, 30-mm diameter SEMS (n= 75, group B). The SEMSs were placed under fluoroscopic guidance and removed by gastroscopy 4,5 days after placement. Data on clinical symptoms, complications, and long-term clinical outcomes were collected, and follow-up observations were performed at 6 months and at 1, 3,5, 5,8, 8,10, and >10 years, postoperatively. Pneumatic dilation and stent placement were technically successful in all of the patients. There were no significant differences in technique success, 30-day mortality, or complications between the two groups. The clinical remission rate in group A was significantly lower than that in group B at 1, 1,3, 3,5, 5,8 and, >10 years (P < 0.05), while the cumulative clinical failure rate in group A (66%, 53/80) was higher than that in group B (92%, 6/75). The mean primary patency in group B was significantly longer than that in group A (4.2 vs 2.1 years, respectively; P < 0.001). A temporary, 30-mm diameter SEMS was associated with a better long-term clinical efficacy in the treatment of patients with achalasia as compared with treatment with pneumatic dilation. [source] Guillain,Barré syndrome in southern Taiwan: clinical features, prognostic factors and therapeutic outcomesEUROPEAN JOURNAL OF NEUROLOGY, Issue 6 2003B.-C. Cheng To determine the clinical features, prognostic factors, and therapeutic results of Guillain,Barré syndrome (GBS) in order to improve the therapeutic strategy for this disease. We retrospectively reviewed the electrodiagnostic study and medical records of patients with GBS admitted to Chang Gung Memorial Hospital, Kaohsiung, between January 1986 and December 2000. Outcomes and prognosis were followed-up after 1 year. Ninety-six patients were enrolled in this study. According to the clinical and electrophysiological findings, 77 patients were acute inflammatory demyelinating polyradiculoneuropathy, seven were Miller Fisher syndrome, and six were axonal forms, and six were unclassified. At a follow-up of 1 year, 61 patients (64%) recovered, 30 (31%) had residua and five (5%) died. Amongst these 30 had residua, including unassisted gait in 19, assisted gait in four, and wheel/bed bound in seven. According to the statistical analysis, disabilities at the nadir (P < 0.0001) and at admission (P = 0.014) were significant prognostic factors. Variables used for the stepwise logistic regression, and the results revealed that after analysis for all the above variables, only disability at the nadir (P < 0.0001) was independently associated with the treatment failure rate. Our study revealed 27% of cases in need of respiratory support during hospitalization, and 5% of hospital-treated patients die from the complications. Furthermore, 31% had residua at a follow-up of 1 year or more. If prognostic factors are considered, disability at the nadir during hospitalization demonstrates consistently poor therapeutic outcomes. Therefore, early diagnosis, choice of appropriate treatment, and preventing complications during acute stages are essential to maximize the potential for survival. [source] Activity-dependent modulation of GABAergic synapses in developing rat spinal networks in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2002Marcelo Rosato-Siri Abstract The role of activity-dependent plasticity in modulating inhibitory synapses was investigated in embryonic rat spinal cord slice cultures, by chronic exposure to non-NMDA receptor blockers. GABAergic synaptic efficacy in control and chronic-treated cultures was investigated by patch-recordings from visually identified spinal interneurons. In both culture groups proximal stimulation induced the appearance of postsynaptic currents (PSCs), which were fully antagonized by 20 µM bicuculline application and reverse polarity at potential values close to those reported for spontaneous GABAergic PSCs. In chronically treated cells GABAergic evoked PSCs displayed a larger failure rate and a smaller coefficient of variation of mean PSC amplitude, when compared to controls. As opposed to controls, chronic GABAergic evoked PSCs did not facilitate upon paired-pulse stimulation. Facilitation at chronic synapses was observed when extracellular calcium levels were decreased below physiological values (< 2 mM). Kainate was used to disclose any functional differences between control and treated slices. In accordance with the presynaptic action of kainate, the application of this drug along with GYKI, an AMPA receptor selective antagonist, changed, with analogous potency, short-term plasticity of GABAergic synapses from control and treated cultures. Nevertheless, in chronic cultures, the downstream effects of such activation unmasked short-term depression. Ultrastructural analysis of synapses in chronically treated cultures showed a reduction both in symmetric synapses and in the number of vesicles at symmetric terminals. Thus, based on electrophysiological and ultrastructural data, it could be suggested that during the development of spinal circuits, GABAergic synapses are modulated by glutamatergic transmission, and thus implying that excitatory transmission regulates the strength of GABAergic synapses. [source] Restorations with extensive dentin/enamel-bonded ceramic coverage.EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2001A 5-year follow-up The durability of restorations with extensive dentin/enamel-bonded posterior partial and complete ceramic coverages were investigated. The effect of luting with a dual-cured and a self-cured luting agent was also studied. In 110 patients, 182 ceramic coverages (IPS Empress) were placed. In 58 restorations, Syntac was used in combination with the dual-cured resin composite Variolink. In the other restorations luted with the chemically cured resin composite Bisfil 2B, 25 were bonded with Gluma, 57 with Allbond 2, and 42 with Syntac. Of the 182 ceramics, 13 (7.1%) were assessed as non-acceptable after a mean observation period of 4.9 yr (range 4.3,7.5 yr). The reasons for failure were fracture (5), lost restorations (4), secondary caries (3) and endodontic treatment (1). No significant differences in failure rate were seen between the two luting agents or between the three dentin-bonding agents. Ceramic coverages placed on non-vital teeth failed in 9.7% of cases (3/31) and on vital teeth in 6.6% (10/151). The success rate of the dentin-enamel-bonded ceramic coverages reduces the need for a traditional full-coverage therapy and/or post or pin(s) and core placement. The technique investigated showed many clinical advantages such as less destruction of healthy tissue, and avoidance of endodontic treatment and/or deep cervical placement of restoration margins. [source] Reliability modelling of uninterruptible power supply systems using fault tree analysis methodEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2009Mohd Khairil Rahmat Abstract The aim of this paper is to investigate the reliability parameters estimation method for the uninterruptible power supply (UPS) systems using the Fault Tree Analysis (FTA) technique. FTA is a top,down approach to identify all potential causes leading to system failure. The computation of the system's failure probability is the main goal of this analysis, as this value can be used to calculate other important system reliability parameters such as failure rates, mean time between failures and reliability. In this paper, the FTA method was applied to five different UPS topologies and the results obtained were compared and discussed in detail. By comparing the critical fault path of the system, it was found that the inverter failures contributed most significantly to the system failure. It was also found that the probability of failure of a UPS system can be reduced by the inclusion of bypass supply, given that the failure rate of the events that causing the failure of the bypass supply should be lower compared to the ones for the main utility supply. Finally, to validate the results obtained from this method, comparisons were made to the results from other methods such as the Reliability Block Diagram, Boolean Truth Table, Probability Tree, Monte-Carlo Simulation and Field Data reliability estimation methods. Copyright © 2008 John Wiley & Sons, Ltd. [source] Analysis of free flap viability based on recipient vein selectionHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 10 2009David O. Francis MD Abstract Background. Venous anastomotic failure is the primary reason for microvascular free tissue transfer failure. Donor and recipient veins can be oriented in the same longitudinal axis (end-to-end anastomosis), or the donor vein can be anastomosed to the internal jugular vein in an end-to-side configuration. No consensus on the optimal anastomosis configuration exists. We sought to evaluate whether type of venous anastomosis impacts flap survival rate. Methods. Data were collected on all patients undergoing microvascular free flap reconstruction of head and neck defects at the University of Washington between August 1993 and April 2007. Flaps with a single venous anastomosis were analyzed. Flaps were stratified into those with end-to-end and end-to-side anastomoses. Survival rates were compared between groups using bivariate and multivariate techniques. Results. Inclusion criteria were met by 786 free flaps; 87% performed in an end-to-end and 13% in an end-to-side configuration. Flap re-exploration and failure rate were 4.3% and 1.1%, respectively. In multivariate analysis, there was no difference in odds of flap re-exploration (OR .70, 95% CI .23,2.18) or flap failure whether or not an end-to-end or end-to-side anastomosis was performed (OR 2.09, 95% CI .38,11.5). Conclusions. In this large cohort of patients, we found no difference in the odds of flap re-exploration or failure based on venous anastomotic configuration. Reconstructive surgeons should have both anastomotic techniques in their repertoire to optimize the success of every flap. © 2009 Wiley Periodicals, Inc. Head Neck, 2009 [source] Radiation therapy for esthesioneuroblastoma: Rationale for elective neck irradiation,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2003Alan T. Monroe MD Abstract Purpose. Esthesioneuroblastoma is an uncommon malignancy of neural crest origin arising in the upper nasal cavity. We describe the University of Florida experience using radiation therapy (RT) in the treatment of this neoplasm, particularly the use of elective nodal irradiation. Materials and Methods. Between May 1972 and August 1998, 22 patients received RT for esthesioneuroblastoma. Two additional patients were treated with palliative intent and were excluded from analysis. Equal numbers of male and female patients were treated, with a median age of 54 years (range, 3,82). The modified Kadish stage was A in 1 patient, B in 4 patients, C in 15 patients, and D in 2 patients. Treatment modalities included primary RT in 6 patients, preoperative RT in 1 patient, postoperative RT after craniofacial resection in 12 patients, and salvage RT in 3 patients treated for recurrence after surgery. Elective neck RT was performed in 11 of 20 patients; 2 patients had cervical metastases at presentation for RT. Results. Rates of local control, cause-specific survival, and absolute survival at 5 years were 59%, 54%, and 48%, respectively. The cause-specific survival rate at 5 years was lower after primary RT (17%) than after craniofacial resection and postoperative RT (56%). Cervical metastases occurred in 6 of 22 patients (27%). No neck recurrences occurred in 11 patients treated with elective neck RT compared with 4 neck recurrences in 9 patients (44%) not receiving elective neck RT (p = .02). Conclusions. Combined modality therapy is preferred over RT alone in advanced-stage esthesioneuroblastoma. Our data and review of the current literature suggest a higher cervical failure rate than previously recognized. Elective neck RT seems to correlate with improved nodal control and should be considered in the treatment of esthesioneuroblastoma. © 2003 Wiley Periodicals, Inc. Head Neck 25: 529,534, 2003 [source] Occipital Nerve Blocks: Effect of Symptomatic MedicationHEADACHE, Issue 10 2009Headache Type on Failure Rate, Overuse Objective., To explore the effect of symptomatic medication overuse (SMO) and headache type on occipital nerve block (ONB) efficacy. Methods., We conducted a chart review of all of the ONBs performed in our clinic over a 2-year period. Results., Of 108 ONBs with follow-up data, ONB failed in 22% of injections overall. Of the other 78%, the mean decrease in head pain was 83%, and the benefit lasted a mean of 6.6 weeks. Failure rate without SMO was 16% overall, and with SMO was 44% overall (P < .000). In those who did respond, overall magnitude and duration of response did not differ between those with and those without SMO. Without SMO, ONB failure rate was 0% for postconcussive syndrome, 14% for occipital neuralgia, 11% for non-intractable migraine, and 39% for intractable migraine. With SMO, failure rate increased by 24% (P = .14) in occipital neuralgia, by 36% (P = .08) for all migraine, and by 52% (P = .04) for non-intractable migraine. Conclusions., SMO tripled the risk of ONB failure, possibly because medication overuse headache does not respond to ONB. SMO increased ONB failure rate more in migraineurs than in those with occipital neuralgia, possibly because migraineurs are particularly susceptible to medication overuse headache. This effect was much more pronounced in non-intractable migraineurs than in intractable migraineurs. [source] Upper digestive bleeding in cirrhosis.HEPATOLOGY, Issue 3 2003Post-therapeutic outcome, prognostic indicators Several treatments have been proven to be effective for variceal bleeding in patients with cirrhosis. The aim of this multicenter, prospective, cohort study was to assess how these treatments are used in clinical practice and what are the posttherapeutic prognosis and prognostic indicators of upper digestive bleeding in patients with cirrhosis. A training set of 291 and a test set of 174 bleeding cirrhotic patients were included. Treatment was according to the preferences of each center and the follow-up period was 6 weeks. Predictive rules for 5-day failure (uncontrolled bleeding, rebleeding, or death) and 6-week mortality were developed by the logistic model in the training set and validated in the test set. Initial treatment controlled bleeding in 90% of patients, including vasoactive drugs in 27%, endoscopic therapy in 10%, combined (endoscopic and vasoactive) in 45%, balloon tamponade alone in 1%, and none in 17%. The 5-day failure rate was 13%, 6-week rebleeding was 17%, and mortality was 20%. Corresponding findings for variceal versus nonvariceal bleeding were 15% versus 7% (P = .034), 19% versus 10% (P = .019), and 20% versus 15% (P = .22). Active bleeding on endoscopy, hematocrit levels, aminotransferase levels, Child-Pugh class, and portal vein thrombosis were significant predictors of 5-day failure; alcohol-induced etiology, bilirubin, albumin, encephalopathy, and hepatocarcinoma were predictors of 6-week mortality. Prognostic reassessment including blood transfusions improved the predictive accuracy. All the developed prognostic models were superior to the Child-Pugh score. In conclusion, prognosis of digestive bleeding in cirrhosis has much improved over the past 2 decades. Initial treatment stops bleeding in 90% of patients. Accurate predictive rules are provided for early recognition of high-risk patients. [source] Lopinavir/ritonavir monotherapy as maintenance treatment in HIV-infected individuals with virological suppression: results from a pilot study in BrazilHIV MEDICINE, Issue 5 2008E Sprinz Objective The aim of the study was to evaluate the possibility of using lopinavir/ritonavir (LPV/RTV) alone as maintenance therapy in HIV-infected individuals with virological suppression. Design This was a single-armed single-centre pilot trial. Methods Asymptomatic HIV-infected patients on highly active antiretroviral therapy (HAART) including LPV/RTV, and with plasma HIV RNA <40 copies/mL for at least 6 months, were enrolled in the study, during which they continued with LPV/RTV alone. The intention was to recruit 25 patients to be followed for 2 years. Viral failure was defined as two consecutive HIV RNA measurements >40 copies/mL. Nadir and baseline CD4 cell counts, highest ever HIV RNA load, time with undetectable viraemia before monotherapy, number of previous antiretroviral (ARV) regimens, and gene polymorphism at CYP3A4 and CYP3A5 were evaluated. Results All patients (27) completed the study. Their median age was 43 years, and 66% were men. Ten patients (37%) failed to maintain virological suppression (the median time to HIV rebound was 10.5 months, with a range of 4,23 months). One patient developed full resistance to LPV and another developed neurocognitive impairment while on LPV/RTV which improved after HAART reintroduction. There were no differences between failures and nonfailures according to the analysed parameters. Patients with viral failure were successfully resuppressed. Conclusions LPV/RTV maintenance therapy was associated with 37% failure, a higher than expected failure rate. In order to ensure that unnecessary risks are not being taken in patients on LPV/RTV, this finding should be further evaluated in large randomized trials for longer periods of follow-up. [source] A 5-year audit of haemodialysis accessINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 7 2005J. A. Akoh Summary This is a review of our experience with vascular access procedures over a 5-year period at Derriford Hospital, Plymouth, UK. The aims of the study were to examine the outcome of vascular access procedures and factors influencing access survival. Between April 1995 and March 2000, 151 patients who underwent 221 vascular access procedures were studied. Of these, 136 had autogenous arteriovenous fistulae, whereas 85 had prosthetic AV grafts (41% in the thigh). The overall primary failure rate was 21% whereas the 1- and 5-year cumulative access survival rates were 60 and 41%, respectively. Thigh grafts have a mean survival of 36 months compared with 32 months for prosthetic upper limb and 43 months for autogenous fistulae. Age, diabetes and predialysis status did not significantly influence access survival. Thrombosis was responsible for access failure in 62 cases (28%). Avoiding subclavian vein canulation and performing vessel mapping prior to access placement should reduce the risk of access failure due to outflow obstruction. [source] Testing whether the epidural works: too time consuming?ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2010J. LARSSON Background: When using epidural anaesthesia (EDA) for pain relief after major surgery, a failure rate of 10% is common. A crucial step in improving the care of patients with EDA is to define the position of the epidural catheter. The aim of this study was to investigate how much time it takes to determine whether the block is sufficient by assessing the extent of loss of cold sensation before induction of anaesthesia. Methods: One hundred patients listed for abdominal surgery were included in the study. After an epidural catheter had been inserted and an intrathecal or an intravenous position had been made unlikely by the use of a test dose, the patient was given a bolus dose of local anaesthetic plus an opioid in the epidural catheter. The epidural block was tested every 2 min, starting at 5 min and ending at 15 min. When at least four segments were blocked bilaterally, the testing was stopped, the time was noted and the patient was anaesthetised. Results: An epidural block was demonstrated after 5,6 min in 37 patients, after 7,8 min in 43 additional patients and after 9,10 min in 15 patients. In one patient, it took 12 min and in three patients, it took 15 min. In two patients, no epidural block could be demonstrated. Conclusion: Testing an epidural anaesthetic before the induction of anaesthesia takes only 5,10 extra minutes. Knowing whether the catheter is correctly placed means better quality of care, giving the anaesthetist better prerequisites for taking care of the patient post-operatively. [source] Tunica albuginea urethroplasty for anterior urethral strictures: A urethroscopic analysisINTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2009Raj K Mathur Objective: To assess the efficacy of tunica albuginea urethroplasty (TAU) for anterior urethral strictures. Methods: We assessed 206 patients with anterior urethral strictures who underwent TAU. The procedure involves mobilization of strictured urethra and laying it open with a dorsal slit. Edges of the slit-open urethra are sutured to edges of the urethral groove with a silicon catheter in situ. Thus in neourethra, the roof is formed by tunica albuginea of the urethral groove. Results were assessed at 6, 12, 24 and 36 months by comparative analysis of patient satisfaction along with retrograde urethrogram, urethrosonogram, uroflowmetry, and were categorized as good, fair and poor. Good and fair results were considered as successful. Thirty patients were taken for postoperative urethroscopic analysis to allow better understanding of both successful and failed cases. Results: Postoperative evaluation at 6 months showed a 96.6% success rate, which decreased to 94.7% at 1 year, 93.2% at 2 years and over 90% at the end of 3 years. The overall failure rate was 9.2%, which required revision surgery. Urethroscopic visualization of the reconstruction site showed wide, patent and distensible neourethra uniformly lined by urothelium over roof formed by tunica albuginea of the corpora cavernosa in successful cases. Failure cases showed diffuse fibrotic narrowing or circumferential scarring. Conclusion: Tunica albuginea is a locally available distensible tissue, sufficient to maintain the patency of the neourethra, without any graft or flap. TAU is easier and useful when patients have unhealthy oral mucosa due to tobacco chewing. [source] Prediction of organ-confined disease by prostate-specific antigen nadir after neoadjuvant therapyINTERNATIONAL JOURNAL OF UROLOGY, Issue 11 2000Takahiko Hachiya Abstract Background It is not clear whether or not serum prostate-specific antigen (PSA) levels after androgen deprivation prior to radical prostatectomy (neoadjuvant therapy) have any value in the prediction of the final pathologic stage. Methods We conducted a study on 49 patients who underwent retropubic radical prostatectomy following neoadjuvant therapy for clinical stage T1c, T2, and T3a prostate cancer. We evaluated progression-free survival based on the PSA failure rate and the predictive value of the PSA nadir after neoadjuvant therapy and other clinical factors to determine the most important predictor of organ confinement. Results Of the 49 patients, 30 had organ-confined disease. Of 31 patients without adjuvant therapy after surgery, the PSA failure-free rates at 2 years were 81.6 and 34.3% in the subset of organ-confined disease and non-organ-confined disease, respectively (P = 0.0031). Of the 18 patients with adjuvant androgen deprivation therapy after surgery, the PSA failure-free rate at 2 years was 100% and 59.7% in patients with organ-confined disease and non-organ-confined disease, respectively. Baseline PSA (P = 0.037), PSA nadir (P < 0.0001) and PSA density (P = 0.003) significantly correlated with organ confinement. Multivariate logistic regression analysis revealed that the PSA nadir was the only independent predictor of organ confinement (P = 0.044). Conclusions There was a trend that the patients with non organ-confined disease had a higher probability of PSA failure than did the patients with organ-confined disease. The PSA nadir after neoadjuvant therapy was the strongest predictor of organ confinement. The predictive value of the serum PSA nadir should be validated in well-designed larger population-based studies. [source] To Replace or Not to Replace: A Systematic Approach to Respond to Device AdvisoriesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2009Ph.D., SILVIA G. PRIORI M.D. Aim: The decision of whether and when to replace a device in response to an "advisory" letter requires careful consideration, because device replacement carries related risks and is influenced by the clinical characteristics of the patient. Methods and Results: The risk/benefit of device replacement depends on four parameters: expected annual sudden cardiac death rate; residual device life; difference in failure rate between the device listed on the advisory letter and the replacement device; and the replacement procedure mortality risk. Using these four factors, we have developed an equation that provides the "number needed to replace" (NNR) to save one life. Per our model, patients implanted with a device with a failure rate approaching 1% and a probability of requiring device intervention ,25% per year,in particular, pacemaker-dependent patients,have an NNR <250. Pacemaker-dependent patients, with devices having three or more years longevity, but with device failure rates ,0.5%, have an NNR <100. Patients with arrhythmic risk ,2.5% per year and those with devices having failure rates <0.1% have a high NNR and stand more risk to be harmed than benefited from device replacement. Conclusions: Pacemaker-dependent patients and those with high arrhythmic risk (,25% annually) when having "advisory" devices with high failure rate (,1%) have an NNR <250 and, hence, could be considered for device replacement. Conversely, patients with arrhythmic risk ,2.5% per year and those with devices having failure rates ,0.1% have a high NNR or even risk of "harm" from device replacement. In all the intermediate cases, the NNR will quantify the benefit/risk ratio of replacement, thus helping physicians and patients decide on the preferred approach. The NNR methodology proposed here is also applicable to advisory notices issued to leads, but the high morbidity associated with lead replacement will generally rule out interventions to replace leads. [source] A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2008Part I: Lateral approach Abstract Objectives: The objectives of this systematic review were to assess the survival rate of grafts and implants placed with sinus floor elevation. Material and Methods: An electronic search was conducted to identify studies on sinus floor elevation, with a mean follow-up time of at least 1 year after functional loading. Results: The search provided 839 titles. Full-text analysis was performed for 175 articles resulting in 48 studies that met the inclusion criteria, reporting on 12,020 implants. Meta-analysis indicated an estimated annual failure rate of 3.48% [95% confidence interval (CI): 2.48%,4.88%] translating into a 3-year implant survival of 90.1% (95% CI: 86.4%,92.8%). However, when failure rates was analyzed on the subject level, the estimated annual failure was 6.04% (95% CI: 3.87%,9.43%) translating into 16.6% (95% CI: 10.9%,24.6%) of the subjects experiencing implant loss over 3 years. Conclusion: The insertion of dental implants in combination with maxillary sinus floor elevation is a predictable treatment method showing high implant survival rates and low incidences of surgical complications. The best results (98.3% implant survival after 3 years) were obtained using rough surface implants with membrane coverage of the lateral window. [source] A systematic review of the success of sinus floor elevation and survival of implants inserted in combination with sinus floor elevation Part II: Transalveolar techniqueJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2008Wah Ching Tan Abstract Objectives: The objectives of this systematic review were to assess the survival rate of implants placed in sites with transalveolar sinus floor elevation. Material and Methods: An electronic search was conducted to identify prospective and retrospective cohort studies on transalveolar sinus floor elevation, with a mean follow-up time of at least 1 year after functional loading. Failure and complication rates were analyzed using random-effects Poisson regression models to obtain summary estimates/ year proportions. Results: The search provided 849 titles. Full-text analysis was performed for 176 articles, resulting in 19 studies that met the inclusion criteria. Meta-analysis of these studies indicated an estimated annual failure rate of 2.48% (95% confidence interval (95% CI): 1.37,4.49%) translating to an estimated survival rate of 92.8% (95% CI): 87.4,96.0%) for implants placed in transalveolarly augmented sinuses, after 3 years in function. Furthermore, subject-based analysis revealed an estimated annual failure of 3.71% (95% CI: 1.21,11.38%), translating to 10.5% (95% CI: 3.6,28.9%) of the subjects experiencing implant loss over 3 years. Conclusion: Survival rates of implants placed in transalveolar sinus floor augmentation sites are comparable to those in non-augmented sites. This technique is predictable with a low incidence of complications during and post-operatively. [source] Effectiveness of educational interventions on the improvement of drug prescription in primary care: a critical literature reviewJOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 2 2001Adolfo Figueiras PhD Abstract This paper is a critical review of studies of educational programmes designed to improve prescription practices in ambulatory care. Scientific articles were selected from the following bibliographical indices: MEDLINE, IME, ICYT and ERIC. The searches covered the time period between 1988 and 1997. The search criteria included: primary-care, educat*, prescription* and other related keywords. The inclusion criteria were studies describing educational strategies aimed at general practitioners working in ambulatory settings. The study outcome was change in prescribing behaviour of physicians through prescribing indicators. The following data were extracted: study design, target drugs, type of intervention, follow-up period of the prescription trends, type of data analysis, type of statistical analysis and reported results. We found 3233 articles that met the search criteria. Of these, 51 met the inclusion criteria and 43 studied the efficacy/effectiveness of one or various interventions as compared to no intervention. Among seven studies evaluating active strategies, four reported positive results (57%), as opposed to three of the eight studies assessing passive strategies (38%). Among the 28 studies that tested reinforced active strategies, 16 reported positive results for all variables (57%). Eight studies were classified as a high degree of evidence (16%). We concluded that the results of our review suggest that the more personalized, the more effective the strategies are. We observe that combining active and passive strategies results in a decrease of the failure rate. Finally, better studies are still needed to enhance the efficacy and efficiency of prescribing practices. [source] Flipper bands do not affect foraging-trip duration of Magellanic PenguinsJOURNAL OF FIELD ORNITHOLOGY, Issue 4 2009P. Dee Boersma ABSTRACT Flipper bands are used to mark penguins because leg bands can injure their legs. However, concerns remain over the possible effects of flipper bands on penguins. We examined the effects of stainless-steel flipper bands on the duration of foraging trips by Magellanic Penguins (Spheniscus magellanicus) at Punta Tombo, Argentina, using an automated detection system. We predicted that, if bands were costly and increased drag, flipper-banded penguins would make longer foraging trips than those with small or no external markings. We tagged 121 penguins with radio-frequency identification (RFID) tags and an additional external mark. We placed either a stainless-steel band on the left flipper (N= 62) or a 2×10-mm small-animal ear tag in the outside web of the left foot (N= 59). We measured foraging-trip durations (N= 376 trips) for 68 adult penguins with chicks from 15 December 2007 to 28 February 2008. Contrary to predictions, trip duration was similar for banded and web-tagged penguins (P= 0.22) and for males and females (P= 0.52), with no interaction between tag type and sex (P= 0.52). No penguins marked in the 2007 breeding season and recaptured between 30 September and 30 November 2008 (N= 113) lost flipper bands or web tags, but three RFID tags failed between March and September 2008. Properly designed and applied flipper bands were a reliable marking method for Magellanic Penguins, had a lower failure rate than RFIDs, and did not affect foraging-trip duration. RESUMEN Los anillos de ala son usados para marcar pingüinos porque los anillos de tarso pueden causar heridas en sus piernas. Sin embargo, existen dudas sobre los posibles efectos de los anillos de ala sobre los pingüinos. Usando un sistema de detección automatizado, examinamos los efectos de anillos de ala hechos de acero inoxidable sobre la duración de los viajes para forrajeo por el pingüino Spheniscus magellanicus en Punta Tombo, Argentina. Predecimos que si los anillos afectarían a los pingüinos e incrementaran la fricción con el agua, los pingüinos con anillos de ala harían viajes para forrajeo de mayor duración en comparación a los que no portaban marcadores externos o que llevaban marcadores externos de menor tamaño. Marcamos a 121 pingüinos con marcadores de identificación por radio frecuencia, además de otro marcador al exterior del ave. Colocamos un anillo de acero inoxidable al ala izquierdo (N= 62), o un marcador de oreja (2×10 mm) para animales pequeños de en la membrana interdigital exterior del pie izquierdo (N= 59). Desde el 15 de diciembre del 2007 hasta el 28 de Febrero del 2008 medimos la duración de los viajes para forrajeo (N= 376 viajes) para 68 pingüinos adultos con pichones. Contrariamente a nuestras predicciones, la duración de los viajes fue similar para pingüinos con anillos y para pingüinos con marcadores en el pie (P = 0.22), así como entre machos y hembras (P= 0.52), con ninguna interacción entre el tipo de marca y el sexo (P= 0.52). Ningún pingüino marcado en la temporada reproductiva del 2007 y recapturado entre el 30 de Septiembre y el 30 de Noviembre del 2008 (N= 113) perdió el anillo de ala o el marcador en el pie, pero tres marcadores de identificación por radio frecuencia fallaron entre Marzo y Septiembre del 2008. Los anillos de ala apropiadamente diseñadas y aplicadas fueron un método de marcaje confiable para S. magellanicus, tuvieron una tasa de fallo menor a los marcadores de identificación por radio frecuencia y no afectaron a la duración de los viajes para forrajeo. [source] Survey of consent practices for inpatient colonoscopy and endoscopic retrograde cholangiopancreatography at a tertiary referral centerJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8 2006Cynthia H Seow Abstract Background:, The purpose of the present paper was to determine informed consent practices for inpatient, open-access colonoscopy and endoscopic retrograde cholangiopancreatography (ERCP) at a tertiary referral center. Methods:, A two-part prospective study incorporating (i) an audit of consent practices for colonoscopy and ERCP; and (ii) a questionnaire directed at gastroenterologists and interns regarding information imparted to patients in the process of acquiring informed consent, was undertaken at Sir Charles Gairdner Hospital, Western Australia. Study subjects consisted of inpatients undergoing open-access colonoscopy and/or ERCP at the study center commencing May 2003; and gastroenterologists and interns at the study center. Results:, Written consent was obtained by junior medical staff in 89% of cases. Response rates for the questionnaire was 100% from interns, and 91% from gastroenterologists. Of interns surveyed, 93% had witnessed a colonoscopy, and 59% had witnessed an ERCP. For 12% of interns, colonoscopic bleeding or perforation were not always mentioned. Colonoscopy failure rate and perforation were overestimated by 51% and 63% of interns, respectively. Only 56% of interns always mentioned pancreatitis as a complication of ERCP. The rate of post-ERCP pancreatitis was overestimated by 25% of interns. Only 40% of gastroenterologists always provided additional information to patients whose consent was obtained by someone else. Written material was not routinely provided for patients. Consent was usually obtained on the day of the procedure. Conclusions:, Written consent for inpatients undergoing open-access colonoscopy and ERCP is rarely obtained by the proceduralist. There is substantial variability in the information provided to patients. Guidelines are required to ensure best practice in this area. [source] Transesophageal Echocardiography and Intracardiac Echocardiography Differently Predict Potential Technical Challenges or Failures of Interatrial Shunts Catheter-Based ClosureJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 1 2007GIANLUCA RIGATELI M.D. We sought to prospectively assess the role of transesophageal (TEE) and intracardiac echocardiography (ICE) in detecting potential technical difficulties or failures in patients submitted to interatrial shunts percutaneous closure. We prospectively enrolled 46 consecutive patients (mean age 35±28, 8 years, 30 female) referred to our center for catheter-based closure of interatrial shunts. All patients were screened with TEE before the intervention. Patients who met the inclusion criteria underwent ICE study before the closure attempt (40 patients). TEE detected potential technical difficulties in 22.5% (9/40) patients, whereas ICE detected technical difficulties in 32.5% (13/40 patients). In patients with positive TEE/ICE the procedural success (92.4% versus 100% and, P = ns) and follow-up failure rate (7.7% versus 0%, P = ns) were similar to patients with negative TEE/ICE, whereas the fluoroscopy time (7 ± 1.2 versus 5 ± 0.7 minutes, P < 0.03), the procedural time (41 ± 4.1 versus 30 ± 8.2 minutes, P ± 0.03), and technical difficulties rate (23.1% versus 0%, P = 0.013) were higher. Differences between ICE and TEE in the evaluation of rims, measurement of ASD or fossa ovalis, and detection of venous valve and embryonic septal membrane remnants impacted on technical challenges and on procedural and flouroscopy times but did not influence the success rate and follow-up failure rate. [source] Distinguishing N -oxide and hydroxyl compounds: impact of heated capillary/heated ion transfer tube in inducing atmospheric pressure ionization source decompositionsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2004Dilrukshi M. Peiris Abstract In the pharmaceutical industry, a higher attrition rate during the drug discovery process means a lower drug failure rate in the later stages. This translates into shorter drug development time and reduced cost for bringing a drug to market. Over the past few years, analytical strategies based on liquid chromatography/mass spectrometry (LC/MS) have gone through revolutionary changes and presently accommodate most of the needs of the pharmaceutical industry. Among these LC/MS techniques, collision induced dissociation (CID) or tandem mass spectrometry (MS/MS and MSn) techniques have been widely used to identify unknown compounds and characterize metabolites. MS/MS methods are generally ineffective for distinguishing isomeric compounds such as metabolites involving oxygenation of carbon or nitrogen atoms. Most recently, atmospheric pressure ionization (API) source decomposition methods have been shown to aid in the mass spectral distinction of isomeric oxygenated (N -oxide vs hydroxyl) products/metabolites. In previous studies, experiments were conducted using mass spectrometers equipped with a heated capillary interface between the mass analyzer and the ionization source. In the present study, we investigated the impact of the length of a heated capillary or heated ion transfer tube (a newer version of the heated capillary designed for accommodating orthogonal API source design) in inducing for-API source deoxygenation that allows the distinction of N -oxide from hydroxyl compounds. 8-Hydroxyquinoline (HO-Q), quinoline- N -oxide (Q-NO) and 8-hydroxyquinoline- N -oxide (HO-Q-NO) were used as model compounds on three different mass spectrometers (LCQ Deca, LCQ Advantage and TSQ Quantum). Irrespective of heated capillary or ion transfer tube length, N -oxides from this class of compounds underwent predominantly deoxygenation decomposition under atmospheric pressure chemical ionization conditions and the abundance of the diagnostic [M + H , O]+ ions increased with increasing vaporizer temperature. Furthermore, the results suggest that in API source decompostion methods described in this paper can be conducted using mass spectrometers with non-heated capillary or ion transfer tube API interfaces. Because N-oxides can undergo in-source decomposition and interfere with quantitation experiments, particular attention should be paid when developing API based bioanalytical methods. Copyright © 2004 John Wiley & Sons, Ltd. [source] The ,frameless' intrauterine system for long-term, reversible contraception: A review of 15 years of clinical experienceJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 3 2003Dirk Wildemeersch Abstract Aim:, The development of the ,frameless' intrauterine system (IUS) is a response to the growing need to develop high-performing, long-acting, reversible, and acceptable contraceptives with a high continuation of use. Methods:, This is a review of 15 years of clinical experience in randomized controlled and non-randomized clinical trials. Results:, The IUS has a similar failure rate as the TCu380A Intrauterine device (IUD), considered the ,golden standard' IUD, which is attributed to the optimal target delivery of the copper ions in the upper part of the uterine cavity. Its performance is further optimized by the atraumatic design, which reduces partial and total expulsion and minimizes the side-effects and discomforts experienced with conventional ,framed' IUDs. The mini IUS is likely to further reduce the menstrual blood loss due to the very small size. The safety of the anchoring concept is beyond doubt as was demonstrated in all clinical studies covering 15 000 woman-years experience. Conclusions:, Young nulliparous/nulligravid and parous women may significantly benefit from the advantages the ,frameless' IUS, which could be strategically important to help in reducing the increasing number of unintended pregnancies and induced abortions worldwide. Furthermore, the ,frameless' IUS has been shown to be highly effective for emergency contraception and for immediate postabortal insertion. The long lifespan of the IUS could constitute a cost-effective reversible alternative to irreversible female sterilization. [source] The effect of retainer thickness on posterior resin-banded prostheses: a finite element studyJOURNAL OF ORAL REHABILITATION, Issue 11 2004T.-S. Lin summary, According to its design concept, a resin-bonded prosthesis, compared with the conventional fixed partial denture, is a weak and unstable structure. Therefore, a resin-bonded prosthesis induces a higher failure rate, especially in the posterior region. Recently, adhesion agents have been profoundly improved. However, the design guidelines of posterior resin-bonded prostheses (RBP) have seldom been evaluated from a biomechanical perspective. The objective of this study was to investigate the biomechanical effects of the retainer thickness on posterior RBP using the finite element method. A solid model of a posterior mandibular resin-bonded prosthesis, which employed the second molar and second premolar as the abutment teeth, was constructed and meshed with various retainer thickness (ranging from 0·2 to 1·0 mm). Horizontal and vertical loadings of 200 N were applied respectively at the central fossa of the pontic to examine the stress level at the interface between the retainer and abutment teeth. All exterior nodes in the root, below the cementoenamel junction were fixed as the boundary condition. The results showed that horizontal loading would induce higher interfacial stresses than the vertical loading which indicated that the horizontal component of the occlusal force plays a more important role in evaluating the debonding phenomenon. Further, the peak interfacial stresses increased as the retainer thickness decreased and, based on the fitted relation between retainer thickness and interfacial stresses, a 0·4 mm retainer thickness was suggested as the minimum required to prevent severe interfacial stresses increasing. [source] A retrospective study of pre-fabricated carbon fibre root canal postsJOURNAL OF ORAL REHABILITATION, Issue 10 2003S.-O. Hedlund summary, Although pre-fabricated carbon fibre posts have been used during the past decade clinical evaluations of the technique are still few. Using dental records and radiographs the clinical performance of 65 pre-fabricated carbon fibre posts (Composipost and Endopost) placed in 48 patients who regularly visited a general practice were evaluated in the present study. After an average time of 2.3 ± 0·8 years (median 2·1 years, range 1,4·9 years) of clinical service the failure rate was 3%. Failure occurred in one tooth with a single crown restoration and in one tooth that was part of a cantilever fixed partial denture. Although the failure rate is lower than those mostly reported for metallic posts and cores more clinical studies are necessary to assess the suitability of pre-fabricated carbon fibre posts for routine use as an alternative to individually cast posts. [source] |