Catheter Ablation of the Atrioventricular Junction Using a Helical Microwave Antenna: A Novel Means of Coupling Energy to the Endocardium

Catheter ablation with either direct current defibrillator discharges or radiofrequency energy produces tissue injury via current flow from an electrode into the adjacent myocardium. In order to affect tissue at a distance, excessive power density may be produced at the electrode-tissue interface with the possibility of explosive gas formation or coagulum formation. A novel microwave catheter was developed with a helical antenna distally. This coil, although not in direct contact with the endocardium, radiates an electromagnetic field into the tissue that, in turn, causes thermal injury. The utility of this system for ablation was assessed in six dogs. The antenna catheter was introduced percutaneously and positioned so as to record the largest His electrogram. Microwave power (50 watts at 2,450 MHz) was applied for 114 +/- 118 seconds. Complete AV block was produced in all six animals with 1.8 +/- 1.2 applications. There was no ventricular ectopy or change in blood pressure during microwave ablation. One dog died 6 days after ablation. The remaining five dogs had persistent, complete AV block during 6 weeks of follow-up. Pathological analysis at 6 weeks revealed a large (mean 2.8 x 4.7 mm) fibrovascular scar in the region of the AV junction. Percutaneous microwave ablation of the endocardium appears feasible. By radiating an electromagnetic field without direct contact, this system can produce large lesions without being limited by desiccation of tissue and impedance rise.     

Preliminary Experience With a Novel Ultrasound‐Guided Supraclavicular Perineural Catheter Insertion Technique for Perioperative Analgesia of the Upper Extremity

Objective. Brachial plexus perineural catheters provide specific analgesia for upper extremity surgery. Although single‐injection ultrasound‐guided supraclavicular blocks have been described, little is known about the efficacy of perineural catheters inserted using this approach. We present our experience with ultrasound‐guided supraclavicular perineural catheters for distal upper extremity surgery. Methods. In this case series, 10 patients who underwent upper extremity surgery for orthopedic trauma at a tertiary care university hospital received a supraclavicular brachial plexus perineural catheter for postoperative pain management. In all patients, a nonstimulating catheter was inserted using an ultrasound‐guided technique with the catheter tip remaining under direct vision until placement needle withdrawal. Postoperatively, a perineural ropivacaine, 0.2%, infusion was administered at a basal rate of 6 mL/h with a patient‐controlled bolus of 4 mL and a lockout interval of 30 minutes. Results. Of the 10 patients, all had successful perineural catheter placement. Patients required a median (range) of 0 (0–100) μg of fentanyl for catheter insertion analgesia. There were no vascular punctures or other direct procedure‐related complications. Catheters were maintained for a median (range) of 4 (2–5) days in both hospitalized and ambulatory patients. Median (range) pain scores on postoperative days 1 and 2 were 5 (0–7) and 4 (3–6), respectively, on a numeric rating scale. Three patients' catheters were removed by patient request or dislodged on postoperative day 1. Conclusions. Supraclavicular brachial plexus perineural catheter insertion using ultrasound guidance is feasible and deserves further study with a randomized controlled trial comparing this relatively new technique with more established approaches.     

Comparing the Effectiveness of a Novel Suction Set-up Using an Adult Endotracheal Tube Connected to a Meconium Aspirator vs. a Traditional Yankauer Suction Instrument

Background

It has been suggested that an adult 8.0 endotracheal tube (ETT) connected to a neonatal meconium aspirator would improve suctioning during emergent endotracheal intubation compared to the Yankauer suction instrument, the standard tool used by emergency physicians.

Screening for Novel Antimicrobials from Encoded Combinatorial Libraries by Using a Two-Dimensional Agar Format

A sensitive lawn-based format has been developed to screen bead-tethered combinatorial chemical libraries for antimicrobial activity. This method has been validated with beads linked to penicillin V via a photocleavable chemical linker in several analyses including a spike-and-recover experiment. The lawn-based screen sensitivity was modified to detect antibacterial compounds of modest potency, and a demonstration experiment with a naive combinatorial library of over 46,000 individual triazines was evaluated for antibacterial activity. Numerous hits were identified, and both active and inactive compounds were resynthesized and confirmed in traditional broth assays. This demonstration experiment suggests that novel antimicrobial compounds can be easily identified from very large combinatorial libraries of small, nonpeptidic compounds.     

A Novel Technique for Teaching Challenging Ultrasound‐Guided Breast Procedures to Radiology Residents

Ultrasound‐guided breast interventions (core biopsies, needle‐wire localizations, and fine‐needle cyst aspirations) are common procedures performed by radiologists. Residents must gain competency in these interventions during training. Phantoms and simulations have been advocated for teaching interventions, and various systems are available for standard breast interventions. However, simulations for difficult/high‐risk interventions are not readily available. We describe an inexpensive method for simulating difficult ultrasound‐guided breast procedures, including masses over breast implants, deep masses along the chest wall, and lymph nodes adjacent to axillary vessels.     

A Simplified Approach to Temporary DDD Pacing Using a Single Lead, Balloon-Tipped Catheter with Overlapping Biphasic Impulse Stimulation

Temporary DDD pacing offers significant hemodynamic benefits in emergency management of bradyarrhythmias but is underused because of its complexity (two leads) and unreliability. Single lead VDD pacing with atrial sensing via a floating dipole is feasible, but atrial pacing is limited by high thresholds and phrenic nerve stimulation (PNS). Overlapping biphasic impulse (OLBI) stimulation may avoid these problems. The authors designed a single lead balloon-tipped catheter for temporary transvenous DDD pacing, incorporating noncontact atrial dipoles for OLBI stimulation. This catheter was deployed using fluoroscopic guidance in 74 patients (43 men, 31 women) with mean age 56.9 +/- 17.0 years. Pacing parameters were assessed at implantation and follow-up. The median procedural time was 6.6 (range 1.2-25.0) minutes and fluoroscopy time 1.9 (range 0.2-7.8) minutes. Stable VDD pacing was achieved in all cases. Atrial capture was achieved in 73 of 74 cases with both modes at maximum output but was restricted by PNS at outputs below atrial capture threshold in 3 of 74 cases with OLBI and 10 of 74 cases with standard bipolar mode (P = 0.04). At outputs > or = 1.0 V above atrial threshold, reliable DDD pacing without PNS was achieved and maintained in 67 (91%) of 74 patients in OLBI compared to 53 (72%) of 74 patients in bipolar mode (P = 0.003). Pacing parameters were stable during follow-up (median 53 hours, range 6-168 hours). In conclusion, the single lead catheter with OLBI stimulation allows temporary VDD and DDD pacing without PNS to be achieved in > 90% of patients. This rapid and convenient approach should facilitate DDD pacing in emergency settings.     

Anterior Cervical Approach for Stellate Ganglion and T2 to T3 Sympathetic Blocks: A Novel Technique

Background: Stellate ganglion block is used for the diagnosis and treatment of sympathetically maintained pain syndromes. Multiple anatomic variations and inaccurate sympathetic block may mislead the diagnosis and prevent patients from receiving potentially beneficial interventions. We describe a novel approach to blockade of the sympathetic chain at C7 and at T2 to T3 with a single‐needle injection. Technique: With the patient in supine position, the uncinate process of C7 is identified fluoroscopically as a target for insertion of a catheter through a Touhy needle. The catheter is directed caudally to the junction of T2 and T3. Contrast injection confirms the spread to the appropriate levels before injection of local anesthetic. Conclusion: This novel approach to blockade of the upper extremity sympathetic innervation may enhance diagnostic accuracy and therapeutic benefit as compared with traditional approaches to the stellate ganglion alone. This approach may be expected to decrease the risk of pneumothorax when compared with the posterior approach to T2 to T3.     

The POCUS Pulse Check: A Case Series on a Novel Method for Determining the Presence of a Pulse Using Point-of-Care Ultrasound

BackgroundDuring cardiopulmonary resuscitation, pulse checks must be rapid and accurate. Despite the importance placed on the detection of a pulse, several studies have shown that health care providers have poor accuracy for detection of central pulses by palpation. To date, the use of point-of-care ultrasound (POCUS) in cardiac arrest has focused on the presence of cardiac standstill and diagnosing reversible causes of the arrest.ObjectiveThis case series highlights a simple, novel approach to determine whether pulses are present or absent by using POCUS compression of the central arteries.DiscussionUsing this technique, we found that a POCUS pulse check can be consistently performed in < 5 s and is clearly determinate, even when palpation yields indeterminate results.ConclusionsIn this case series, the POCUS pulse check was a valuable adjunct that helped to change management for critically ill patients. Future prospective studies are required to determine the accuracy of this technique and the impact on patient outcomes in a larger cohort.     

Reproducible Surveillance Breast Ultrasound Using an Image Fusion Technique in a Short-Interval Follow-up for BI-RADS 3 Lesions: A Pilot Study

The aim of our study was to verify the utility of surveillance ultrasound (US) using real-time virtual sonography (RVS) - to coordinate present US images with past US images reconstructed from previously acquired US volume data using an image fusion technique - for short-interval follow-up of Breast Imaging-Reporting and Data System (BI-RADS) category 3 mass lesions. We enrolled 20 women (23 lesions) with more than 24 mo of follow-up after classification as BI-RADS category 3 during initial US. US surveillance was scheduled at 6, 12 and 24 mo. Measurement of the target lesion diameter was performed after the probe was adjusted to include the maximum diameter of a past US image at each visit. RVS was technically successful in 100% of patients. All target lesions were detected, including two iso-echoic lesions. The mean target lesion diameters at baseline and at 6, 12 and 24 mo were 8.2 ± 4.2, 8.4 ± 4.5, 8.1 ± 4.5 and 8.3 ± 5.0 mm, respectively (p = 0.785). Our results suggest that RVS is a reproducible, operator-independent technique for comparison of US images of BI-RADS category 3 mass lesions obtained at different time points.     

A relational approach to providing care for a person suffering from dementia

AIMS OF THE PAPER: This paper examines the care provision for people suffering from dementia and explores the potential benefits associated with an approach to care that emphasizes the importance of relationships. BACKGROUND: Recent research findings have provided an incentive to re-evaluate the established approaches to care for this client group. Two separate studies identified education and intellectual stimulation as important determinants of the onset of Alzheimer's disease (Ott et al. 1995, Snowdon et al. 1996). These findings have encouraged the hypothesis that potential symptomatic benefits may be achieved by providing a more stimulating environment for people with dementia. METHODS: A case study is outlined which illustrates an approach to caring influenced by the Continental philosopher, Emmanuel Levinas. Primacy is given to the relationships that make up caring, and not to a method that sets out to achieve an identified objective. The issue of mutual responsibility within the provision of care is highlighted in the case study. FINDINGS: The hypothesis presented in this paper is that a person has more of an opportunity to develop to the limits of their potential by establishing the importance of relationships in providing care by means of education and training of the people involved. The beneficiaries might be the caregiver or the person in receipt of care. CONCLUSIONS: An environment that attempts to educate people to recognize the importance of relationships will be more effective in achieving the potential benefits of symptom alleviation identified by the research into Alzheimer's disease outlined in this paper.