Evaluation of a New Needle Guidance System for Ultrasound: Results of a Prospective, Randomized, Blinded Study.

BACKGROUND AND OBJECTIVES: Accurate needle control during ultrasound (US)-guided nerve blocks may be an elusive goal for the anesthesiologist. Despite modifications to increase echogenicity, needle visibility still requires precise alignment within the transducer beam. In this study, we evaluated a magnetically guided ultrasound (MGU) system that produces a real-time, graphic display of the needle position and trajectory that is independent of the US beam. METHODS: The MGU system was compared with echogenic needles and conventional ultrasound (CU) by anesthesiologists with and without prior experience performing US-guided nerve blocks. Participants were asked to perform tasks to quantify accuracy with respect to needle direction (directional accuracy) and needle tip position (positional accuracy). These evaluations were performed in a porcine tissue model. RESULTS: Regarding directional accuracy, inexperienced subjects were able to contact a target capsule with a single needle pass during both in-plane (IP) and out-of-plane (OOP) approaches using the magnetic guidance system. By contrast, using CU, subjects required redirection 3.8 ± 2.4 (P = 0.02), and 4.5 ± 3.9 (P = 0.04) times, respectively, for IP and OOP approaches. Experienced subjects contacted the target capsule with a single pass for both IP and OOP approaches when using the magnetic guidance system. With CU, experienced subjects were able to contact the target with a single pass using an IP approach but required redirection 3.4 ± 2.8 (P = 0.046) times during OOP approaches. Positional accuracy was also superior for both inexperienced (P = 0.04) and experienced (P = 0.02) users during an OOP approach. CONCLUSIONS: In a tissue model, the MGU system improved control of needle trajectory and needle tip position for both inexperienced and experienced subjects.

Local anesthetic injection deep to the fascia iliaca at the level of the inguinal ligament: the pattern of distribution and effects on the obturator nerve.

STUDY OBJECTIVE: The femoral, lateral femoral cutaneous, and obturator nerves (ONs) can reportedly be blocked using a single-injection deep to the fascia iliaca (FI) at the level of the inguinal ligament. Two commonly used methods (the FI compartment and 3-in-1 blocks) have produced inconsistent results with respect to local anesthetic distribution and effect on the ON. To date, no study of either method has been performed using advanced imaging techniques to document both needle placement and local anesthetic distribution. We report the outcome of a series of 3-in-1 and FI blocks performed using ultrasound to guide needle position and magnetic resonance imaging (MRI) to define local anesthetic distribution. DESIGN: Patients were prospectively studied, and images were interpreted using a randomized and blinded protocol. SETTING: The study was performed in the perioperative area of an academic orthopedic specialty hospital. PATIENTS: Ten patients (ASA 1-2) having anterior cruciate ligament reconstruction received either 3-in-1 or FI compartment blocks for postoperative analgesia using the surface landmarks described for these techniques. INTERVENTIONS: Ultrasound was used to position the injecting needle immediately deep to the FI. Local anesthetic distribution was studied using MRI. MEASUREMENTS: Patients were examined for motor and/or sensory function of the femoral, obturator, and lateral femoral cutaneous nerves. Magnetic resonance imaging was used to document the limits of injectate distribution. MAIN RESULTS: Magnetic resonance imaging showed distribution of injectate over the surface of the iliacus and psoas muscles to the level of the retroperitoneum. No patient showed medial extension of injectate to the ON. At the level of the inguinal ligament, injectate extended laterally toward the anterior superior iliac spine and medially to the femoral vein. All patients had significant weakness with extension of the knee and sensory loss over the anterior, lateral, and medial thigh. No patient demonstrated decreased hip adductor strength. CONCLUSIONS: Ultrasound and MRI show consistent superior extension of local anesthetic to the level of the retroperitoneum for both techniques. There was reliable clinical effect on the femoral and lateral femoral cutaneous nerves. However, none of the injections produced evidence of ON block either at the level of the retroperitoneum or the inguinal ligament.

Serotonin syndrome manifesting as patient movement during total intravenous anesthesia with propofol and remifentanil.

A patient who manifested signs of serotonin syndrome during an intravenous anesthetic with remifentanil and propofol is presented. The patient displayed lower extremity clonus, nystagmus, and diaphoresis. At the time of surgery, the patient was being treated with fluoxetine (a selective serotonin reuptake inhibitor). A presumptive diagnosis of serotonin syndrome was made intraoperatively and all opioids were discontinued. His symptoms resolved in the Postanesthesia Care Unit without incident.

Anatomic changes in the inguinal region after hip arthroscopy: implications for femoral nerve block.

Patients may experience significant pain after hip arthroscopy. Two patients who experienced severe pain after arthroscopic hip surgery, despite receiving multimodal pharmacologic therapy, are presented. In both cases, ultrasound-guided femoral nerve block provided excellent analgesia. However, during ultrasound, significant anatomic changes were noted in the inguinal region. In this report, we describe anatomic changes in the inguinal region that are visible with ultrasound after hip arthroscopy.

Three-times-daily subcutaneous unfractionated heparin and neuraxial anesthesia: a retrospective review of 928 cases.

BACKGROUND AND OBJECTIVES: Subcutaneous (SC) unfractionated heparin (UFH) administered 3 times daily (TID) is widely used for venous thromboembolism prophylaxis in the perioperative period. There are no data in the literature regarding the incidence of adverse outcomes with neuraxial analgesia in the setting of this regimen. In this retrospective review, we report the incidence of untoward events related to anticoagulation with SC UFH TID in patients with indwelling epidural catheters. METHODS: We queried the electronic hospital databases to identify patients receiving thoracic epidural analgesia in conjunction with 5000 U UFH SC TID from July 2008 to October 2010. In this group, we identified the diagnoses of neuraxial hematoma, deep vein thrombosis, or pulmonary embolism and examined measured blood coagulation parameters. In addition, we determined the percentage of patients receiving concomitant therapy with ketorolac. RESULTS: We identified 928 patients who received thoracic epidural analgesia in conjunction with 5000 U UFH SC TID during this period. There were no cases of neuraxial bleeding. Seven patients had a diagnosed deep vein thrombosis or pulmonary embolism. Thirty-four percent (315/928) of patients received ketorolac. The measured activated thromboplastin time was more than 40 seconds (35 seconds being the upper limit of normal) in 115 patients (12%). CONCLUSIONS: Given the rare incidence of neuraxial hematoma, statements regarding the appropriateness of epidural analgesia in the setting of TID SC UFH cannot be made from this limited sample size. At present, information regarding epidural hematoma in the setting of a TID SC UFH dosing regimen does not exist in the literature. Our study represents an initial step in the accumulation of data needed to prove or disprove the safety of this practice.

Improving individual measurement of postoperative pain: the pain trajectory.

UNLABELLED: The purpose of this study was to demonstrate a method for increasing the precision and information yield of postoperative pain assessment. We recorded pain intensity ratings over 6 days after surgery in 502 elective surgery patients and examined individual pain trajectories. A linear fit of an individual patient's scores defines a trajectory with two features: (1) the intercept or initial pain intensity; and (2) the slope, or rate of pain resolution. Three pain trajectory patterns emerged from examination of the pain trajectory slopes. Most patients (63% of the sample) demonstrated a negative slope trajectory characterized by a decline in pain intensity over days after surgery. Other patients (25% of the sample) demonstrated a flat trajectory with no meaningful change over 6 days from pain they reported initially. A third patient group (12% of the sample) had a positive slope trajectory in which pain scores increased over 6 days after surgery. Measures derived from individual pain trajectories yielded much lower standard errors of measurement and therefore had better measurement precision than did conventional pain assessment methods. Pain trajectory measures proved sufficiently precise to characterize pain patterns reliably in individual patients. PERSPECTIVE: Progress in acute pain management requires effective pain assessment. The acute pain trajectory quantifies rate of pain resolution as well as pain intensity. It affords more precise measurement than conventional pain assessment and can identify abnormal postoperative pain resolution.

Ambulatory anesthesia and regional catheters: when and how.

Several clinical trials have demonstrated the superiority of continuous peripheral nerve block compared with traditional opioid-based analgesia. The ability to provide safe and effective continuous peripheral nerve block at home is an attractive alternative to opioid-based analgesia with its related side effects. In this article, the practical issues related to catheter use in the ambulatory setting are discussed. Techniques for catheter placement, infusion regimens, patient education, and complications are subject to many institutional preferences. In this review, special emphasis is placed on evidence-based techniques.

Interscalene block for postoperative analgesia using only ultrasound guidance: the outcome in 200 patients.

STUDY OBJECTIVE: To report the results of single and continuous interscalene blocks (ISB) performed using ultrasound (US) guidance only. DESIGN: Prospective, observational study. SETTING: Operating room of a university-affiliated orthopaedic hospital. PATIENTS: 200 ASA physical status I, II, and III patients undergoing shoulder or elbow surgery. INTERVENTIONS: Single or continuous ISB were placed using US guidance only. All blocks were performed by anesthesiology residents and supervised by faculty anesthesiologists. MEASUREMENTS: Success rate and frequency of untoward events such as needle paresthesia, vessel puncture, infection, and persistent neurologic deficits were prospectively recorded. MAIN RESULTS: 99% of patients reported sensory and motor changes in the distribution of the brachial plexus and postoperative pain scores

A novel approach for assessing catheter position after ultrasound-guided placement of continuous interscalene block.

The increasing use of ultrasound has allowed anesthesiologists to perform nerve blocks with a high success rate and without nerve stimulation or eliciting a paresthesia. The ability to visualize peripheral nerve catheters using ultrasound is limited. We present a novel method to confirm the position of an interscalene catheter tip using injection of agitated contrast. The described technique is simple and allows timely assessment of catheter tip position.

Delaware's Wellness Program: Motivating Employees Improves Health and Saves Money.

BACKGROUND: Every year, employers around the country evaluate their company benefits package in the hopes of finding a solution to the ever-rising cost of health insurance premiums. For many business executives, the only logical choice is to pass along those costs to the employee. OBJECTIVES: As an employer, our goal in Delaware has always been to come up with innovative solutions to drive down the cost of health insurance premiums while encouraging our employees to take responsibility for their own health and wellness by living a healthy and active lifestyle, and provide them with the necessary tools. METHODS: The DelaWELL program (N = 68,000) was launched in 2007, after being tested in initial (N = 100) and expanded (N = 1500) pilot programs from 2004 to 2006 in which 3 similar groups were compared before and after the pilot. Employee health risk assessment, education, and incentives provided employees the necessary tools we had assumed would help them make healthier lifestyle choices. RESULTS: In the first pilot, fewer emergency department visits and lower blood pressure levels resulted in direct savings of more than $62,000. In the expanded pilot, in all 3 groups blood pressure was significantly reduced (P <.001) from preprogram to postprogram; body fat reduction was also significant (P <.001); and glucose levels dropped (P <.001) in 2 groups. The overall saving was about $450,000. And in only about 4 months this year, 729 employees participating in DelaWELL had a combined weight loss of 5162 lb. CONCLUSIONS: Decision makers in the State of Delaware have come up with an innovative solution to controlling costs while offering employees an attractive benefits package. The savings from its employee benefit program have allowed the state to pass along the savings to employees by maintaining employee-paid health insurance contributions at the same level for the past 3 years. DelaWELL has already confirmed our motto, "Although it may seem an unusual business investment to pay for healthcare before the need arises, in Delaware we concluded that this makes perfect sense." This promising approach to improving health and reducing healthcare costs could potentially be applied to other employer groups.

Racial and gender differences in susceptibility to tobacco smoke among patients with chronic obstructive pulmonary disease.

BACKGROUND: Although chronic obstructive pulmonary disease (COPD) has been considered a disease of Caucasian men, recent data show mortality rising faster among women and African-Americans. Some have suggested these groups are more susceptible to tobacco smoke. We examined this issue in our own population of COPD patients. METHODS: Beginning in March 2003 we prospectively developed a COPD research database to facilitate recruitment for clinical trials. Enrollees are recruited from clinics and paid advertising and their demographics, medical/smoking histories, and spirometric data are recorded. We examined the smoking histories and pulmonary function of enrollees over 45, with 20 pack-years of smoking, FEV(1)/FVC (forced expiratory volume forced vital capacity) <0.70, and a race-adjusted post-bronchodilator FEV(1)<80%. The primary outcome was the loss of lung function per pack-year smoked, or Susceptibility Index (SI), calculated using the formula: (% predicted FEV(1)-100)/pack-years. RESULTS: A total of 585 patients enrolled during the study period and 330 met our inclusion criteria. Caucasians were older than African-Americans (63 vs. 58, P=0.0003) and had more pack-years of smoking (57 vs. 43, P=0.0003). There were no differences in lung function or bronchodilator reversibility among the racial or gender subgroups. Caucasians had less loss of lung function per pack-year smoked than African-Americans (SI=-1.02% vs. -1.34%, P=0.007) and men less than women (SI=-0.98% vs. -1.21%, P=0.001). Caucasian males appeared relatively protected from tobacco smoke (SI=-0.93%), while African-American women appeared most susceptible (SI=-1.42%). CONCLUSIONS: There are important differences in racial and gender susceptibility to tobacco smoke among patients with COPD. African-American females appear to be at highest risk and may benefit most from smoking cessation.

Preoperative "fentanyl challenge" as a tool to estimate postoperative opioid dosing in chronic opioid-consuming patients.

UNLABELLED: When opioids are used for postoperative pain control, it is useful to define the dose-response relationship for analgesia and respiratory depression. We studied 20 chronically opioid-consuming patients having elective multilevel spine fusion. Preoperatively, each patient received a fentanyl infusion of 2 microg x kg(-1) x min(-1) until the respiratory rate was <5 breaths/min. Pharmacokinetic simulations were used to estimate the effect site concentration at the time of respiratory depression and to predict the patient-controlled analgesia settings that would provide an effect-site fentanyl concentration that was 30% of the concentration associated with respiratory depression. Postoperatively, patient-controlled analgesia settings were adjusted to achieve 2-3 demand doses per hour. At steady-state patient-controlled analgesia settings, arterial blood gases and plasma fentanyl levels were measured. Sixteen patients required no adjustment or one patient-controlled analgesia adjustment. The median arterial Pco(2) level was 41 mm Hg and the interquartile range was 39-46 mm Hg. Plasma fentanyl levels demonstrated a significant correlation to the estimated effect-site concentration associated with respiratory depression determined during the preoperative fentanyl challenge. A preoperative fentanyl challenge used with pharmacokinetic simulations may be a useful tool to individualize the administration of analgesics to chronically opioid-consuming patients. IMPLICATIONS: In chronically opioid-consuming patients, doses causing respiratory depression and analgesia may differ from those in opioid-naive individuals. A preoperative infusion of fentanyl, used in conjunction with pharmacokinetic simulation, may be a valuable tool for identifying clinical end-points, such as respiratory depression and analgesia, and individualizing postoperative treatment of pain in patients who chronically consume opioids.