Color Doppler ultrasonography of an agitated solution is predictive of accurate catheter placement for a continuous popliteal sciatic nerve block.

BACKGROUND: Continuous peripheral nerve catheters (PNCs) have been shown to provide superior postoperative analgesia, decrease opioid consumption, and improve patient satisfaction compared with single injection techniques. In order to achieve success and reliability, accurate catheter positioning is an essential element of PNC placement. An agitated solution of normal saline, D5W, or a local anesthetic solution can be produced by the introduction of air to the injectate, creating air bubbles that can enhance ultrasonographic visualization and possibly improve block success. METHODS: Eighty-three patients were enrolled. Ultrasound-guided continuous popliteal sciatic nerve blocks were performed by positioning the tip of a Tuohy needle between the tibial and common peroneal branches of the sciatic nerve and threading a catheter. An agitated local anesthetic solution was injected through the catheter, viewed with color Doppler ultrasound and video recorded. A peripheral block score (lower score = greater blockade, range 0-14) was calculated based upon the motor and sensory testing at 10, 20, and 30 min after block completion. The color Doppler agitation coverage pattern for the branches of the sciatic nerve was graded as follows: complete (> 50%), partial (> 0%, ≤ 50%), or none (0%). RESULTS: The degree of nerve blockade at 30 min as judged by median (10th, 90th percentile) peripheral block score was significant for partial or complete color Doppler coverage of the sciatic nerve injectate compared to no coverage [3 (0, 7) vs 8 (4, 14); p < 0.01] and block onset was faster (p = 0.03). The block success was higher in groups with partial or complete coverage of the branches of the sciatic nerve vs no coverage (96% vs 70%; p = 0.02). CONCLUSIONS: Injection of an agitated solution through a popliteal sciatic perineural catheter is predictive of accurate catheter placement when partial or complete coverage of the sciatic nerve branches is visualized with color Doppler ultrasound. TRIAL REGISTRATION: NCT01591603.

Regulating Ionizing Radiation Based on Metrics for Evaluation of Regulatory Science Claims.

This article attempts to reconcile differences within the relevant scientific community on the effect of exposure to low levels of ionizing radiation notably the applicability of linear nonthreshold (LNT) process at exposures below a certain limit. This article applies an updated version of Metrics for Evaluation of Regulatory Science Claims (MERSC) derived form Best Available Regulatory Science (BARS) to the arguments provided by the proponents and opponents of LNT. Based on BARS/MERSC, 3 categories of effects of exposure to ionizing radiation are identified. One category (designated as S) consists of reproducible and undisputed adverse effects. A second category (designated as U) consists of areas where the scientific evidence for potential adverse effects includes uncertainties. The scientific evidence in the U category leads to a threshold. In contrast, the scientific foundation of the third category (designated as P) is questionable, as the scientific evidence indicates that adverse effects of the exposure at this level are not only questionable but may be helpful. This article claims that the third area is the domain of policy makers including regulators. This article describes Jeffersonian Principle that categorizes the affected community into specialists, knowledgeable nonspecialists, and the general public. Based on Jeffersonian Principle, the relevant scientific information, particularly the U and P areas, must be translated into a language that at a minimum is understandable to the knowledgeable group. Once this process is completed, the policy makers including regulators may select exposure limits based on their judgment.

Comprehensive Analysis of 13,897 Consecutive Regional Anesthetics at an Ambulatory Surgery Center.

Objective: The authors investigated a wide range of perioperative outcome measures in the context of a robust regional anesthesia practice. Design: Comprehensive review of a prospectively collected six-year database. Setting: Freestanding, academic ambulatory surgery center. Subjects: There were 13,897 consecutive regional anesthetics in 10,338 patients. Methods: We investigated patient satisfaction, postoperative nausea and vomiting (PONV), postoperative pain, catheter analgesia, and complications. Clinical risk factors were examined and presented as odds ratios for multiple outcome analyses including block success, patient satisfaction, PONV, and postoperative neurologic symptoms (PONS). Results: Decreased block success was associated with nerve stimulation alone (P < 0.001), obesity (P = 0.001), higher American Society of Anesthesiologists classification (ASA; P = 0.01), lower extremity blocks (P = 0.04), and male sex (P < 0.001). Decreased patient satisfaction was associated with poor catheter analgesia (P < 0.001), complications (P < 0.001), higher ASA (P = 0.001), and younger age (P = 0.008). PONV was associated with postoperative pain (P < 0.005), female sex (P < 0.001), general anesthesia (P < 0.001), younger age (P = 0.001), lack of catheter (P = 0.03), and lack of dexamethasone/clonidine (D + C) adjuncts (P = 0.01). Serious complications and unexpected hospitalizations were rare (<0.2%). D + C adjuncts, lower extremity blocks, clonidine (but not dexamethasone alone), and female sex were associated with PONS (all P < 0.001). Conclusions: A regional anesthesia-based practice in ambulatory surgery is an effective means of providing excellent postoperative analgesia and is associated with a low rate of PONV and unexpected admissions. Dexamethasone, clonidine, and their combination when combined with 0.5% ropivacaine may have mixed effects on PONS risk that warrant dose/concentration alterations of these three drugs in the context of off-label perineural adjunct use.

Regulatory science requirements of labeling of genetically modified food.

This paper provides an overview of the evolution of food labeling in the USA. It briefly describes the three phases of agricultural development consisting of naturally occurring, cross-bred, and genetically engineered, edited or modified crops, otherwise known as Genetically Modified Organisms (GMO). It uses the Best Available Regulatory Science (BARS) and Metrics for Evaluation of Regulatory Science Claims (MERSC) to evaluate the scientific validity of claims applicable to GMO and the Best Available Public Information (BAPI) to evaluate the pronouncements by public media and others. Subsequently claims on health risk, ecological risk, consumer choice, and corporate greed are evaluated based on BARS/MERSC and BAPI. The paper concludes by suggesting that labeling of food containing GMO should consider the consumer's choice, such as the food used by those who desire kosher and halal food. Furthermore, the consumer choice is already met by the exclusion of GMO in organic food.

Continuous peripheral nerve block catheter infections in combat-related injuries: a case report of five soldiers from Operation Enduring Freedom/Operation Iraqi Freedom.

DESIGN: Case series. SETTING: Military medical facility providing acute care for soldiers injured while fighting in the war in Iraq and Afghanistan. OBJECTIVE: To report a series of infections related to use of continuous peripheral nerve catheters for postoperative pain control in the military polytraumatic setting. The analysis of the above infections includes similarities and differences in infection patterns and attempts to clarify possible risk factors for such infections to include duration of catheter placement, type of catheter, preprocedural antibiotics, and tunnel vs nontunneled catheters. The goal of this analysis is to assist in the development of protocols that may prevent future catheter infections. METHODS: Clinical data were obtained from five previously healthy male soldiers receiving acute care at Brooke Army Medical Center using continuous peripheral nerve catheters for postoperative pain for multiple and frequent procedures. RESULTS: In a total of six catheter infections, two were noted to have superficial skin infections while four were shown to have deep tissue involvement confirmed by imaging studies. All patients were started on initial or additional antibiotics after catheter removal. Three catheter infections, all with stimulating catheters, required surgical irrigation and debridement in the operating room. CONCLUSIONS: Continuous peripheral nerve catheters are not without complications and risks including infection. Duration of catheter use was the most significant factor with the development of a catheter-related infection in our series. This series also highlights how stimulating and nonstimulating catheter infections may present differently, as stimulating catheters may have a greater tendency to present as deep space infections with minimal superficial findings.

Rectus sheath catheters for continuous analgesia after laparotomy--without postoperative opioid use.

OBJECTIVE: Opioid and epidural analgesia have been the mainstay for postoperative pain control following laparotomies, yet have many potential side effects, risks, and limitations. This case report offers an alternative to opioid as well as epidural analgesia, which may be beneficial in some patients. DESIGN: We report a case of a patient who underwent a laparotomy with extensive lysis of adhesions who was treated postoperatively with continuous bilateral rectus sheath catheters and multimodal adjuncts including gabapentin, clonidine, and nonsteroidal anti-inflammatories. RESULTS: We successfully used a novel, multimodal approach that avoided the use of epidural analgesia and postoperative opioids. The patient was extremely satisfied, reported minimal discomfort, ambulated early, advanced her diet quickly, and was discharged home after a short hospital stay. CONCLUSIONS: This report may be the first description of a successful multimodal postoperative analgesic regimen including continuous bilateral rectus sheath blocks without inpatient postoperative opioid use or epidural analgesia following a midline laparotomy.