The implantable cardioverter defibrillator: technology, indications, and impact on cardiovascular survival

Since the introduction of the implantable cardioverter defibrillator (ICD) for the management of patients with high risk of arrhythmic SCD, there has been increasing use of this device. Its basic promise to effectively terminate ventricular tachycardia (VT)-ventricular fibrillation (VF) has been repeatedly met. In several randomized trials, the ICD has been shown to be superior to conventional anti-arrhythmic therapy, both in patients with documented VT-VF (secondary prevention) and those with high risk such as left ventricular ejection fraction and no prior sustained VT-VF (primary prevention). In both groups, the ICD showed overall and cardiac mortality reduction. The device now can more accurately detect VT-VF and differentiate these from other arrhythmias through a series of algorithms and direct-chamber sensing. Therapy options include painless antitachycardia pacing, low-energy cardioversion, and high-energy defibrillation. The technique implant is now simple as a pacemaker with one lead attached to an active (hot) can functioning as the other electrode. Among other improvements is its weight, volume, multiprogrammability, and storage of information,dual-chamber pacing and sensing, dual-chamber defibrillation, and addition of biventricular pacing for cardiac synchronization. It is anticipated that further improvement in ICD technology will take place and the list of indications will grow.     

Interventions to reduce mortality among patients treated in intensive care units

PURPOSE: Using sensitivity analysis to estimate the impact, in terms of patient lives, of the failure to use proven therapies known to reduce mortality in critically ill intensive care unit patients. MATERIALS AND METHODS: We identified high-impact interventions published in the last 5 years in the Journal of the American Medical Association or New England Journal of Medicine, extracted the absolute risk reduction associated with each intervention and gleaned the national incidence of each condition and the percent of the population not receiving the cited therapy from the literature. From this information, we calculated national estimates of the excess deaths from failure to use these therapies. RESULTS: With consistent and appropriate implementation of the 5 cited evidence-based interventions, we found a total of 167,819 lives could be saved per year, with a range of 137,670 to 197,965 lives saved per year. CONCLUSIONS: Mistakes of omission are common in the critical care setting and lead to significant preventable mortality. There is a significant gap between the discovery of effective interventions and their use in clinical practice. By viewing the delivery of healthcare as a science and increasing funding for health services research, we may be able to increase the use of effective therapies and, as a result, reduce patient mortality.     

Factors affecting learning during health education sessions

Background noise and interruption were examined for their effects on learning health information. The final sample consisted of 48 college students randomly assigned to one of four conditions in a pretest-posttest, double-blind, 2 x 2 experiment comparing noise (noise/no noise) by interruption (interruption/no interruption). Students viewed one of four videotapes about safe antibiotic use and then completed the posttest. The group watching the videotape with no distraction learned significantly more than the group watching the videotape with noise and with interruption. The results suggest that distraction during health teaching adversely affects the ability to learn health information.     

Inguinal hernia recurrence following preperitoneal Kugel patch repair

Three hundred eighty-six preperitoneal inguinal herniorrhaphies using a polypropylene Kugel patch (Davol) were performed in 355 consecutive patients by six surgeons. Variables for recurrence evaluated included age, gender, hernia type, whether the Kugel patch was placed for a primary or recurrent hernia, and the experience of the surgeon. Of 336 patients with long-term follow-up available (18 months to 63 months, median 42 months) 28 recurrences developed 1 to 48 months (mean 16 months) after 366 Kugel patch repairs (7.7%). Recurrence was highest (27.8%) in the subset of patients who had a Kugel patch placed for recurrent inguinal hernias (P < 0.05). Patients with direct primary hernias involving the entire floor had a recurrence rate of 22.7 per cent (P < 0.05). Patient age and gender had no bearing on recurrence. Surgeon experience did play a role, as the recurrence rate was 18.2 per cent during each surgeon's first 36 cases and 2.9 per cent thereafter (P < 0.0005). Surgeons using a preperitoneal Kugel patch for inguinal herniorraphy had a recurrence rate that was unacceptably high. The technique may not be suitable for repair of recurrent inguinal hernias or primary large direct inguinal hernias. Surgeons in this study saw a learning curve of 36 cases.     

Ultrasound-guided lumbar facet nerve block: a sonoanatomic study of a new methodologic approach

BACKGROUND: Lumbar facet nerve (medial branch) block for pain relief in facet syndrome is currently performed under fluoroscopic or computed tomography scan guidance. In this three-part study, the authors developed a new ultrasound-guided methodology, described the necessary landmarks and views, assessed ultrasound-derived distances, and tested the clinical feasibility. METHODS: (1) A paravertebral cross-axis view and long-axis view were defined under high-resolution ultrasound (15 MHz). Three needles were guided to the target point at L3-L5 in a fresh, nonembalmed cadaver under ultrasound (2-6 MHz) and were subsequently traced by means of dissection. (2) The lumbar regions of 20 volunteers (9 women, 11 men; median age, 36 yr [23-67 yr]; median body mass index, 23 kg/m2 [19-36 kg/m2]) were studied with ultrasound (3.5 MHz) to assess visibility of landmarks and relevant distances at L3-L5 in a total of 240 views. (3) Twenty-eight ultrasound-guided blocks were performed in five patients (two women, three men; median age, 51 yr [31-68 yr]) and controlled under fluoroscopy. RESULTS: In the cadaver, needle positions were correct as revealed by dissection at all three levels. In the volunteers, ultrasound landmarks were delineated as good in 19 and of sufficient quality in one (body mass index, 36 kg/m2). Skin-target distances increased from L3 to L5, reaching statistical significance (*, **P < 0.05) between these levels on both sides: L3r, 45+/-6 mm*; L4r, 48+/-7 mm; L5r, 50+/-6 mm*; L3l, 44+/-5 mm**; L4l, 47+/-6 mm; L5l, 50+/-6 mm**. In patients, 25 of 28 ultrasound-guided needles were placed accurately, with the remaining three closer than 5 mm to the radiologically defined target point. CONCLUSION: Ultrasound guidance seems to be a promising new technique with clinical relevance and the potential to increase practicability while avoiding radiation in lumbar facet nerve block.     

Liver malignancies: CT-guided interstitial brachytherapy in patients with unfavorable lesions for thermal ablation

PURPOSE: To evaluate computed tomography (CT)-guided brachytherapy in patients with very large liver malignancies or with liver tumors located adjacent to the liver hilum. MATERIALS AND METHODS: In this prospective nonrandomized phase II trial, we treated 20 patients (19 liver metastases and one cholangiocarcinoma) with CT-guided high-dose-rate (HDR) brachytherapy using a (192) Iridium source. All patients demonstrated no functional liver degradation prior to irradiation. Entry criteria were liver tumors > 5 cm (group A, n = 11, no upper limit) or liver tumors < or = 5 cm adjacent to the liver hilum (group B, n = 9). Dose planning for brachytherapy was performed with three dimensional (3D) CT data acquired after percutaneous applicator positioning. Magnetic resonance (MR) imaging follow-up was performed 6 weeks and every 3 months post intervention. Primary endpoints were complications, local tumor control (absence of tumor growth after treatment followed by shrinkage of the lesion starting at 6 months) and progression-free survival. RESULTS: The mean tumor diameter was 7.7 cm (range, 5.5-10.8 cm) in group A, 3.6 cm (range, 2.2-4.9 cm) in group B. On average, a minimal dose of 17 Gy in the target volume was applied (range, 12-25 Gy). Severe side effects were recorded in two patients (10%). One patient demonstrated an obstructive jaundice caused by tumor edema after irradiation of a metastasis adjacent to the bile duct bifurcation. One patient developed intra-abdominal hemorrhage that was treated by a single blood transfusion and has ceased. We frequently encountered moderate increases of liver enzymes (70% of patients) and bilirubin (50% of patients) without clinical symptoms and thus considered to be insignificant. The median follow-up was 13 months. In group A (tumors > 5 cm), primary local tumor control after 6 and 12 months was 74% and 40%, respectively; in group B, it was 100% and 71%, respectively. All but one local recurrence (in a patient with diffuse tumor progression) were successfully treated during another CT-guided brachytherapy leading to a primary assisted local control of 93% after 12 months. CONCLUSION: CT-guided brachytherapy based on individual dose plans and 3D CT data sets generated encouraging results in large liver malignancies as well as in tumors located adjacent to the liver hilum.     

Anterior femoroacetabular impingement: part II. Midterm results of surgical treatment

Femoroacetabular impingement has been shown to cause labral and chondral lesions and leads to osteoarthrosis of the hip. With the elimination of the pathogenic cause we hope to prevent or delay additional degeneration of the hip. Fourteen men and five women with a mean age of 36 years (range, 21-52 years) were treated with a surgical dislocation and offset creation of the hip. The followup averaged 4.7 years (range, 4-5.2 years). Using the Merle d'Aubigné hip score, 13 hips were rated excellent to good, with the pain score improving from 2.9 points to 5.1 points at the latest followup. There was no avascular necrosis of the femoral head. Five of the 19 patients, two with Grade 2 osteoarthrosis, two with Grade 1 osteoarthrosis but severe acetabular cartilage damage, and one with untreated ossified labrum had subsequent total hip arthroplasty (THA). In the stable hips without subluxation of the head into the acetabular cartilage defect, no additional joint space narrowing occurred. Surgical dislocation with correction of femoroacetabular impingement yields good results in patients with early degenerative changes not exceeding Grade 1 osteoarthrosis. This procedure is not suitable for patients with advanced degenerative changes and extensive articular cartilage damage.     

Biomechanics of large femoral heads: what they do and don't do

The stability and durability of total hip reconstruction is dependent on many factors that include the design and anatomic orientation of prosthetic components. An analysis of femoral component head size and acetabular component orientation shows an interdependency of these variables and joint stability. Increased femoral component head size can increase hip stability by increasing the prosthetic impingement-free range of hip motion and by increasing the inferior head displacement required before hip dislocation. Increasing the femoral head size from 22 mm to 40 mm increases the required displacement for dislocation by about 5 mm with the acetabular component at 45 degrees of abduction; however, increasing acetabular component abduction greatly diminishes this stability advantage of larger femoral heads. Vertical acetabular component orientation and femoral component head subluxation are each predicted to more than double the tensile stress with acetabular component polyethylene compared with components at 45 degrees of abduction. With a desirable acetabular component orientation, the use of larger femoral heads may result in improved joint stability and durable use of polyethylene. With high abduction acetabular component orientation, the use of larger femoral heads contributes little to joint stability and contributes to elevated stress within the polyethylene that may result in implant failure.     

Carpal tunnel syndrome: a question of hand and wrist configurations?

This study investigated whether there is an association between hand and wrist configurations and the occurrence of carpal tunnel syndrome. The external hand and wrist dimensions of 50 subjects with carpal tunnel syndrome and 50 healthy volunteers were measured and compared. In addition carpal tunnel depth and width were determined with ultrasound. Our results showed that the hand length was significantly higher in the control group (hand length, 19.0; SD, 1.0 cm: patients' hand length, 18.2; SD, 1.1cm) and the palm width was significantly greater in the patients' group (palm width, 9.1; SD, 0.7 cm: controls palm width, 8.6; SD, 0.6 cm). Carpal tunnel syndrome patients had a squarer wrist (wrist ratio, 0.72; SD, 0.1) and carpal tunnel (carpal tunnel ratio, 0.48; SD, 0.1) than the controls (wrist ratio, 0.68; SD, 0.1; carpal tunnel ratio, 0.42; SD, 0.1). These findings indicate that the anatomy of the hand, wrist and carpal tunnel may predispose to carpal tunnel syndrome.