Rajnish K. Gupta

Selective local anesthetic placement using ultrasound guidance and neurostimulation for infraclavicular brachial plexus block.

BACKGROUND: In this study, we performed the infraclavicular block with combined ultrasound guidance and neurostimulation to selectively target cords to compare the success rates of placing a single injection of local anesthetic either in a central or peripheral location. METHODS: Two hundred eighteen patients were enrolled in a consecutive, prospective study. Patients were randomized to injection of local anesthetic either centrally (posterior cord) or peripherally (medial or lateral cord) using ultrasound guidance and neurostimulation. Supervised senior anesthesiology residents or attending anesthesiologists performed the blocks. Both intent-to-treat and treatment-received analyses were used to compare central and peripheral placement efficacy. RESULTS: The overall success rate was significantly higher for the central placements than peripheral placements (96% vs 85%, P = 0.004). Individual cord success rates were as follows: posterior 99%, lateral 92%, and medial 84% (P = 0.001). The central group required attending physician intervention more frequently (27% vs 6%, P < 0.001). Postoperative pain scores of ⩽3 were more likely with central placement (100% vs 94%, P = 0.012). CONCLUSION: Central placement of a single injection of local anesthetic targeted at the posterior cord resulted in a higher success rate for infraclavicular block.

Endogenous opioid function mediates the association between laboratory-evoked pain sensitivity and morphine analgesic responses

Summary Individual differences in endogenous opioid function predict morphine analgesic responses, and these endogenous opioid differences mediate the association between greater laboratory‐evoked pain sensitivity and greater analgesic responses to morphine. ABSTRACT Predictors of responsiveness to opioid analgesic medications are not well understood. This study tested whether individual differences in endogenous opioid (EO) function are associated with analgesic responsiveness to morphine. In randomized, counterbalanced order over 3 sessions, 45 chronic low back pain participants and 31 healthy controls received an opioid antagonist (8 mg naloxone), morphine (0.08 mg/kg), or placebo. Participants then engaged in 2 laboratory‐evoked pain tasks (ischemic and thermal). Outcomes included pain threshold, pain tolerance, and pain ratings. Indexes of EO function and morphine analgesic responsiveness were derived for each measure as the difference in pain responses between the placebo condition and naloxone or morphine condition, respectively. For all 7 pain measures across the 2 laboratory pain tasks, greater EO function was associated with significantly lower morphine analgesic responsiveness (P < 0.001–P = 0.02). Morphine reduced pain responses of low EO individuals to levels similar to those of high EO individuals receiving placebo. Higher placebo condition–evoked pain sensitivity was associated with significantly greater morphine analgesic responsiveness for 5 of 7 pain measures (P < 0.001–P = 0.02). These latter associations were significantly mediated by EO function for 4 of these 5 pain outcomes (all P values < 0.05). In the laboratory‐evoked pain context, opioid analgesic medications may supplement inadequate EO analgesia, with little incremental benefit in those with preexisting high EO function. Implications for personalized medicine are discussed.

The Impact of Peripheral Nerve Techniques on Hospital Stay Following Major Orthopedic Surgery

OBJECTIVE To determine the impact of regional anesthesia on hospital stay for selected orthopedic procedures compared with traditional pain control modalities. DESIGN In an era of an increasing volume of orthopedic surgeries, pain modalities that can optimize patient care while minimizing hospital length of stay can have an impact on reducing hospital costs as well as increasing patient satisfaction and improving patient outcomes. Previous studies have shown the potential benefits of regional anesthesia over traditional intravenous (IV) narcotics in meeting these goals in selected orthopedic procedures. METHODS We retrospectively analyzed the medical records of 494 patients who underwent major orthopedic procedures performed with traditional postoperative pain management alone (IV patient-controlled analgesia and oral narcotics), single injection peripheral nerve block (PNB), and continuous peripheral nerve block (CPNB) in order to determine the impact that different pain modalities might have on hospital length of stay. RESULTS When compared with traditional pain control modalities, single PNB and CPNB were associated with decreased length of hospital stay, though results for specific surgeries varied. The hazard ratios for hospital discharge from a Current Procedural Terminology code-stratified, covariate (age, gender, and ASA status) adjusted Cox proportional hazards model for single PNB vs no PNB and for CPNB vs no PNB were 1.35 (95% confidence interval: 1.02-1.79) and 1.91 (95% confidence interval: 1.42-2.57), respectively, pointing toward earlier hospital discharge when PNBs were used. CONCLUSIONS Our retrospective case review showed that, overall, hospital lengths of stay tended to be shorter for orthopedic surgery patients receiving single PNB and CPNB than for those receiving no block and traditional pain management.

Regional anesthesia, time to hospital discharge, and in-hospital mortality: a propensity score matched analysis.

Background and Objectives The anesthetic technique used during surgery can affect postoperative length of stay and outcomes, even after controlling for other clinically important factors. This study evaluated the impact of regional anesthesia (RA) compared with general anesthesia (GA) on the amount of time between leaving the operating room and hospital discharge and the odds of in-hospital mortality. Methods Surgical patients admitted after surgery, who received RA, were matched to patients who received GA by propensity score in a 1:4 ratio. We measured the association between anesthetic technique and time to hospital discharge using Kaplan-Meier methods. In-hospital mortality was analyzed using a generalized estimating equation logistic regression model. Results A total of 5870 inpatient surgical cases were analyzed; 1174 cases received RA and 4696 cases received GA. The median time to hospital discharge among patients who received RA was 67.6 hours compared with 71.9 hours among patients who received GA (P < 0.0001). A total of 86 cases died in the hospital after surgery; 7 were in the RA cohort and 79 were in the GA cohort. Receiving RA during surgery was associated with 64% lesser odds of dying in the hospital (odds ratio, 0.36; 95% confidence interval, 0.16–0.75), when adjusting for the number of postoperative days spent in the hospital. Conclusions The study data provide evidence that median time to discharge is shorter when RA is used instead of GA, controlling for other clinically important factors. Additionally, RA use during surgery was associated with a decrease in in-hospital mortality. When an appropriate option, RA may facilitate faster hospital discharge and improve patient outcomes.

Endogenous opioid inhibition of chronic low-back pain influences degree of back pain relief after morphine administration.

Background and Objectives Factors underlying differential responsiveness to opioid analgesic medications used in chronic pain management are poorly understood. We tested whether individual differences in endogenous opioid inhibition of chronic low-back pain were associated with the magnitude of acute reductions in back pain ratings after morphine administration. Methods In randomized counterbalanced order over three sessions, 50 chronic low-back pain patients received intravenous naloxone (8 mg), morphine (0.08 mg/kg), or placebo. Back pain intensity was rated predrug and again after peak drug activity was achieved using the McGill Pain Questionnaire–Short Form (Sensory and Affective subscales, VAS Intensity measure). Opioid blockade effect measures to index degree of endogenous opioid inhibition of back pain intensity were derived as the difference between predrug to postdrug changes in pain intensity across placebo and naloxone conditions, with similar morphine responsiveness measures derived across placebo and morphine conditions. Results Morphine significantly reduced back pain compared with placebo (McGill Pain Questionnaire–Short Form Sensory, VAS; P < 0.01). There were no overall effects of opioid blockade on back pain intensity. However, individual differences in opioid blockade effects were significantly associated with the degree of acute morphine-related reductions in back pain on all measures, even after controlling for effects of age, sex, and chronic pain duration (P < 0.03). Individuals exhibiting greater endogenous opioid inhibition of chronic back pain intensity reported less acute relief of back pain with morphine. Conclusions Morphine appears to provide better acute relief of chronic back pain in individuals with lower natural opioidergic inhibition of chronic pain intensity. Possible implications for personalized medicine are discussed.

Improving needle visualization by novice residents during an in-plane ultrasound nerve block simulation using an in-plane multiangle needle guide.

OBJECTIVE Ultrasound-guided regional anesthesia with in-plane needle approaches can be challenging due to difficult needle visualization. We hypothesized that an in-plane, multiangle needle guide can help reduce the time it takes novice regional anesthesiologists to perform a simulated ultrasound-guided nerve-targeting procedure and enhance the visualization of the needle. DESIGN Crossover simulation study. SETTING Simulation environment at an academic institution. SUBJECTS Volunteer trainees in their postgraduate years 1 and 2. METHODS Sixteen subjects were randomized to repeat a single nerve targeting simulation task four times with and four times without a needle guide. End points were time to complete the nerve targeting, needle visualization, number of passes, and needle approximation to the target. RESULTS The needle guide reduced median time to complete the task by 27% (95% confidence interval: 4-44%) and increased the odds of an acceptable needle visualization by 355% (95% confidence interval: 171-737%). A learning benefit for the time outcome was also noted, with multiple attempts regardless of whether the needle guide was used or not. CONCLUSIONS A needle guide can help reduce the time needed to complete a simulated nerve targeting procedure and enhance needle visualization for the novice sonographer in a phantom gel simulation. There was no significant reduction in the number of needle passes or in improvement of target approximation noted.

Upgrading a Social Media Strategy to Increase Twitter Engagement During the Spring Annual Meeting of the American Society of Regional Anesthesia and Pain Medicine

Abstract Microblogs known as “tweets” are a rapid, effective method of information dissemination in health care. Although several medical specialties have described their Twitter conference experiences, Twitter-related data in the fields of anesthesiology and pain medicine are sparse. We therefore analyzed the Twitter content of 2 consecutive spring meetings of the American Society of Regional Anesthesia and Pain Medicine using publicly available online transcripts. We also examined the potential contribution of a targeted social media campaign on Twitter engagement during the conferences. The original Twitter meeting content was largely scientific in nature and created by meeting attendees, the majority of whom were nontrainee physicians. Physician trainees, however, represent an important and increasing minority of Twitter contributors. Physicians not in attendance predominantly contributed via retweeting original content, particularly picture-containing tweets, and thus increased reach to nonattendees. A social media campaign prior to meetings may help increase the reach of conference-related Twitter discussion.

Avoiding Adverse Events Secondary to Opioid-Induced Respiratory Depression: Implications for Nurse Executives and Patient Safety.

BACKGROUND: Guidelines with recommendations for monitoring type and timing of hospitalized patients for opioid-induced respiratory depression have been published, yet adverse events continue to occur. OBJECTIVE: This study reports on the monitoring practices of 8 hospitals that volunteered to pilot test a Centers for Medicare & Medicaid Services e-quality measure that was under development. Recommendations for nurse executives are provided to support patient safety. METHODS: Data on monitoring practices were collected retrospectively from the electronic medical records at 8 hospitals on all patients receiving intravenous (IV) opioids for more than 2.5 continuous hours via patient-controlled analgesia (PCA). Analysis included the percentage of patients who were monitored according to specific standards developed by a panel of technical experts with comparisons of naloxone use to monitoring practices. RESULTS: Recommended patient assessments occurred in only 8.3% of the patients. No patients who were assessed at least every 2.5 hours received naloxone. CONCLUSIONS: Care for patients receiving IV PCA is lacking in adherence to latest safety standards. Nurse executives must implement structures and processes to promote vigilance with evidence-based monitoring practices.

The Contribution of Differential Opioid Responsiveness to Identification of Opioid Risk in Chronic Pain Patients

UNLABELLED The Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R) predicts increased risk of opioid misuse in chronic pain patients. We evaluated whether higher SOAPP-R scores are associated with greater opioid reinforcing properties, potentially contributing to their predictive utility. Across 2 counterbalanced laboratory sessions, 55 chronic low back pain sufferers completed the SOAPP-R at baseline and measures of back pain intensity, evoked pain responsiveness (thermal, ischemic), and subjective opioid effects after receiving intravenous morphine (.08 mg/kg) or saline placebo. Morphine effect measures were derived for all outcomes, reflecting the difference between morphine and placebo condition values. Higher SOAPP-R scores were significantly associated with greater desire to take morphine again, less feeling down and feeling bad, and greater reductions in sensory low back pain intensity following morphine administration. This latter effect was due primarily to SOAPP-R content assessing medication-specific attitudes and behavior. Individuals exceeding the clinical cutoff (18 or higher) on the SOAPP-R exhibited significantly greater morphine liking, desire to take morphine again, and feeling sedated; less feeling bad; and greater reductions in sensory low back pain following morphine. The SOAPP-R may predict elevated opioid risk in part by tapping into individual differences in opioid reinforcing effects. PERSPECTIVE Based on placebo-controlled morphine responses, associations were observed between higher scores on a common opioid risk screener (SOAPP-R) and greater desire to take morphine again, fewer negative subjective morphine effects, and greater analgesia. Opioids may provide the best analgesia in those patients at greatest risk of opioid misuse.

Expectancy Effects on Conditioned Pain Modulation Are Not Influenced by Naloxone or Morphine

BackgroundRecent studies suggest that participant expectations influence pain ratings during conditioned pain modulation testing. The present study extends this work by examining expectancy effects among individuals with and without chronic back pain after administration of placebo, naloxone, or morphine.PurposeThis study aims to identify the influence of individual differences in expectancy on changes in heat pain ratings obtained before, during, and after a forearm ischemic pain stimulus.MethodsParticipants with chronic low back pain (n = 88) and healthy controls (n = 100) rated heat pain experience (i.e., “test stimulus”) before, during, and after exposure to ischemic pain (i.e., “conditioning stimulus”). Prior to testing, participants indicated whether they anticipated that their heat pain would increase, decrease, or remain unchanged during ischemic pain.ResultsAnalysis of the effects of expectancy (pain increase, decrease, or no change), drug (placebo, naloxone, or morphine), and group (back pain, healthy) on changes in heat pain revealed a significant main effect of expectancy (p = 0.001), but no other significant main effects or interactions. Follow-up analyses revealed that individuals who expected lower pain during ischemia reported significantly larger decreases in heat pain as compared with those who expected either no change (p = 0.004) or increased pain (p = 0.001).ConclusionsThe present findings confirm that expectancy is an important contributor to conditioned pain modulation effects, and therefore significant caution is needed when interpreting findings that do not account for this individual difference. Opioid mechanisms do not appear to be involved in these expectancy effects.