Samuel Gledhill

Preliminary Results of the Australasian Regional Anaesthesia Collaboration: A Prospective Audit of More Than 7000 Peripheral Nerve and Plexus Blocks for Neurologic and Other Complications

Background and Objectives: Peripheral nerve blockade is associated with excellent patient outcomes after surgery; however, neurologic and other complications can be devastating for the patient. This article reports the development and preliminary results of a multicenter audit describing the quality and safety of peripheral nerve blockade. Methods: From January 2006 to May 2008, patients who received peripheral nerve blockade had data relating to efficacy and complications entered into databases. All patients who received nerve blocks performed by all anesthetists during each hospitals contributing period were included. Patients were followed up by phone to detect potential neurologic complications. The timing of follow-up was either at 7 to 10 days or 6 weeks postoperatively, depending on practice location and time period. Late neurologic deficits were defined as a new onset of sensory and/or motor deficit consistent with a nerve/plexus distribution without other identifiable cause, and one of the following: electrophysiologic evidence of nerve damage, new neurologic signs, new onset of neuropathic pain in a nerve distribution area, paresthesia in relevant nerve/plexus distribution area. Results: A total of 6950 patients received 8189 peripheral nerve or plexus blocks. Of the 6950 patients, 6069 patients were successfully followed up. In these 6069 patients, there were a total of 7156 blocks forming the denominator for late neurologic complications. Thirty patients (0.5%) had clinical features requiring referral for neurologic assessment. Three of the 30 patients had a block-related nerve injury, giving an incidence of 0.4 per 1000 blocks (95% confidence interval, 0.08-1.1:1000). The incidence of systemic local anesthetic toxicity was 0.98 per 1000 blocks (95% confidence interval, 0.42-1.9:1000). Conclusions: These results indicate that the incidence of serious complications after peripheral nerve blockade is uncommon and that the origin of neurologic symptoms/signs in the postoperative period is most likely to be unrelated to nerve blockade.

Reference Range for Intrapatient Variability in Blood-Pool and Liver SUV for 18F-FDG PET

18F-FDG PET qualitative tumor response assessment or tumor-to-background ratios compare targets against blood-pool or liver activity; standardized uptake value (SUV) semiquantitation has artifacts and is validated by a stable normal-tissue baseline. The aim of this study was to document the normal intrapatient range of scan-to-scan variation in blood-pool SUV and liver SUV and to identify factors that may adversely affect it (increase its spread). Methods: Between July 2009 and June 2010, 132 oncology patients had 2 PET/CT scans. Patient preparation, acquisition, and reconstruction protocols were held stable, uniform, and reproducible. Mean SUV (body weight) values were obtained from 2-dimensional regions of interest in the aortic arch blood pool and in the right lobe of the liver. Results: Of the 132 patients, 65 had lymphoma. Their mean age was 62.5 y. The group’s mean serum glucose level was 6.0 mmol/L at the first visit and 5.9 mmol/L at the second visit. The mean 18F-FDG dose was 4.1 MBq/kg at the first visit and 4.0 at the second. At the first visit, the group’s mean blood-pool SUV was 1.55 (SD, 0.38); at the second, 1.58 (SD, 0.37)—not statistically different. The group’s mean liver SUV was 2.17 (SD, 0.44) at the first visit and 2.29 (SD, 0.44) at the second (P = 0.005). Visit-to-visit intrapatient variation in blood-pool and liver SUVs had gaussian distributions. The variation in blood-pool SUV had a mean of 0.03 and SD of 0.42. The variation in liver SUV had a mean of 0.12 and SD of 0.50. Using 95th percentiles, the reference range in our patient population for intrapatient variation was −0.8 to 0.9 for blood pool SUV and −0.9 to 1.1 for liver SUV. Subanalysis by cancer type and chemotherapy suggested that the rise in liver SUV between the 2 visits was largely due to the commencement of chemotherapy, but no factors were identified as systematically affecting intrapatient variation, and no factors were identified as increasing its spread. Conclusion: In our patient cohort, the reference range for intrapatient variation in blood-pool and liver SUVs is −0.8 to 0.9 and −0.9 to 1.1, respectively.

ultrasound-guided Midthigh Sciatic Nerve Block—a Clinical and Anatomical Study

Background and Objectives: Ultrasound‐guided sciatic nerve block is a relatively new regional anesthesia technique with few descriptions in the literature. The objective of this study was to assess the ease with which the sciatic nerve could be imaged in the midthigh region using ultrasound and to describe the anatomy surrounding the sciatic nerve at this location. Methods: In this prospective observational study, 40 patients scheduled for surgery where sciatic nerve block was indicated were scanned between the gluteal and the popliteal regions using an ultrasound machine (Vivid‐i®, GE Healthcare, Chalfont St. Giles, Bucks, UK). Patients then received real time ultrasound‐guided sciatic nerve block. Validation of the ultrasound image of the sciatic nerve was achieved using nerve stimulation. Description and confirmation of the anatomy surrounding the sciatic nerve was based on a review of anatomical texts and an anatomical study on 5 unembalmed cadavers. Results: The sciatic nerve was identified with ultrasound and its image validated using nerve stimulation in 38 of 40 patients (95%). In 15 patients (37.5%) nerve stimulation was required to confirm identification of the sciatic nerve. Surrounding muscles (biceps femoris, vastus lateralis, and adductor magnus) and fascial planes (lateral intermuscular septum) were identified as sonographic landmarks and were confirmed in the anatomical study. Conclusions: Ultrasonic identification of the sciatic nerve at the midthigh level can be achieved; however, in this study, 37.5% of patients required nerve stimulation to confirm its sonographic appearance. Target nerve localization and the subsequent performance of the sciatic nerve block may be enhanced by recognition of surrounding muscular and fascial structures which were also identified using ultrasound.

Comparison of 3MP medical-grade to 1MP office-grade LCD monitors in mammographic diagnostic and perceptual performance

Introduction: Picture archiving and communication systems images designed to be viewed on high‐resolution medical‐grade monitors are routinely viewed on office‐grade monitors on the wards or at home. This study aimed to determine whether a statistically significant difference in diagnostic (cancer detection) and perceptual (microcalcification detection) performance exists between 3MP grade and 1MP office‐grade monitors.

Diagnostic accuracy of mammography readers and their memory performance have no correlation with each other.

Introduction:  The study aims to determine if any association exists between visual memory performance and diagnostic accuracy performance in a group of radiologist mammogram readers.

ORIGINAL ARTICLE: Diagnostic accuracy of mammography readers and their memory performance have no correlation with each other

Introduction:  The study aims to determine if any association exists between visual memory performance and diagnostic accuracy performance in a group of radiologist mammogram readers.

Intrareader variability in mammographic diagnostic and perceptual performance amongst experienced radiologists in Australia.

Introduction: The purpose of this study was, for a group of experienced radiologists, to identify the magnitude of and statistical significance of intrareader variability in mammographic diagnostic performance or cancer diagnosis and mammographic perceptual performance or microcalcification detection.

A Randomized Controlled Trial of Ultrasound Versus Nerve Stimulator Guidance for Axillary Brachial Plexus Block

Background Ultrasound-guided techniques improve outcomes in regional anesthesia when compared with traditional techniques; however, this assertion has not been studied with novices. The primary objective of this study was to compare sensory and motor block after axillary brachial plexus block when performed by novice trainees allocated to an ultrasound- or nerve–stimulator-guided group. A secondary objective was to compare the rates of skill acquisition between the 2 groups. Methods This study was a prospective, randomized, observer-blinded, 2-arm controlled trial. Anesthesia trainees participating in this trial were novices to axillary brachial plexus block and sonography. All trainee participants underwent a standardized training program. The primary outcome was combined sensory and motor block in the relevant territories 30 minutes after completion of block. A global rating scale was used to assess trainee block performance. Results The study was ceased after 12 trainees completed 153 blocks. There was no difference between groups in combined motor-sensory score (P = 0.28) or as a function of block number (P = 0.38). There was no difference in onset between groups (P = 0.38). In both groups, there was an increase in the global rating scale score (P < 0.0001) and reduced preblock survey and block performance times (P = 0.001) with experience. Conclusions We were unable to demonstrate a difference in the efficacy of axillary brachial plexus block performed by novices when ultrasound guidance was compared with a nerve stimulator technique. There was evidence of similarly improved clinical performance of novices in both groups.

Comparison of readers' detection of right-sided and left-sided breast cancers and microcalcifications

Introduction: Aim of this study was to determine if there is a statistically and clinically significant difference in diagnostic performance (cancer diagnosis) and perceptual performance (microcalcification detection) when detecting left‐sided or right‐sided breast cancers and microcalcifications.

Cancer on a mammogram is not memorable: Readers remember their recalls and not cancers

To determine if presence of cancer on a mammogram makes that mammogram more memorable.