Readiness for Discharge After Foot and Ankle Surgery Using Peripheral Nerve Blocks: A Randomized Controlled Trial Comparing Spinal and General Anesthesia as Supplements to Nerve Blocks.

BACKGROUND: Neuraxial anesthesia is often viewed as superior to general anesthesia but may delay discharge. Comparisons do not typically use multimodal analgesics and nerve blockade. Combining nerve blockade with general anesthesia may reduce pain, opioid consumption, and nausea. We hypothesized that general anesthesia (with nerve blocks) would lead to earlier readiness for discharge, compared to spinal anesthesia (with nerve blocks). METHODS: All patients underwent ambulatory foot and ankle surgery, with a predicted case duration of 1-3 hours. All patients received popliteal and adductor canal nerve blocks using bupivacaine and dexamethasone. No intraoperative opioids were administered. All patients received ondansetron, dexamethasone, ketamine, and ketorolac. Patients, data collectors, and the data analyst were not informed of group assignment. Patients were randomized to spinal or general anesthesia with concealed allocation. Spinal anesthesia was performed with mepivacaine and accompanied with propofol sedation. After general anesthesia was induced with propofol, a laryngeal mask airway was inserted, followed by sevoflurane and propofol. Time until ready for discharge, the primary outcome, was compared between groups after adjusting for age and surgery time using multivariable unconditional quantile regression. Secondary outcomes compared at multiple timepoints were adjusted for multiple comparisons using the Holm-Bonferroni step-down procedure. RESULTS: General anesthesia patients were ready for discharge at a median of 39 minutes earlier (95% confidence interval, 2-75; P = .038) versus spinal anesthesia patients. Patients in both groups met readiness criteria for discharge substantially before actual discharge. Pain scores at rest were higher among general anesthesia patients 1 hour after leaving the operating room (adjusted difference in means, 2.1 [95% confidence interval, 1.0-3.2]; P < .001). Other secondary outcomes (including opioid use, opioid side effects, nausea, headache, sore throat, and back pain) were not different. CONCLUSIONS: General anesthesia was associated with earlier readiness for discharge, but the difference may not be clinically significant and did not lead to earlier actual discharge. Most secondary outcomes were not different between groups. The choice of spinal or general anesthesia as an adjunct to peripheral nerve blockade can reflect patient, clinician, and institutional preferences.

Association of obesity with inflammation and pain after total hip arthroplasty.

BACKGROUND: The prevalence of obesity is increasing, and obesity often leads to degenerative joint disease requiring total hip arthroplasty (THA). Obesity is a proinflammatory state associated with an increase in chronic, low-grade inflammatory response. As such, it may augment the postoperative inflammatory response, which has been associated with postoperative pain and complications. QUESTIONS/PURPOSES: We determined whether severity of obesity was associated with (1) severity of inflammatory response, as measured by the in vivo circulating levels of cytokines and ex vivo functional reactivity of mononuclear blood cells, and (2) severity of pain, as measured by verbal pain scores and analgesic consumption, in the first 24 hours after THA. METHODS: We studied 60 patients (20 normal weight, 20 overweight, 20 obese) undergoing elective primary unilateral THA in this prospective cross-sectional study. Blood samples were collected for C-reactive protein and cytokine levels, including IL-1ß, IL-2, IL-6, IL-8, and tumor necrosis factor α (TNF-α), from patients before and 24 hours after surgery. Cytokine response of whole blood was evaluated ex vivo with or without two standard activators, phorbol-12-myristate-13-acetate and lipopolysaccharide, using standardized blood sample from patients at 24 hours. These standard immune activators are implicated in the inflammatory response to gram-negative infection, translocation of microbial products, pathophysiology of septic shock syndrome in human, and tumor promotion. Pain response was gauged using verbal pain scores (on a 0- to 10-point scale, where 0 = no pain and 10 = worst pain) at rest and with activity at 24 hours after surgery and analgesic consumption of volume of epidural analgesic solution for the first 24 hours after surgery. RESULTS: No correlation was found between BMI and postoperative spontaneous circulating cytokine levels. However, after activation of blood leukocytes with lipopolysaccharide, there was a significant positive correlation between the BMI and IL-1ß, IL-6, and TNF-α levels (r = 0.26-0.32; p = 0.03, p = 0.03, and p = 0.01, respectively), suggesting priming of the innate immune system in obesity and potential for excessive postoperative inflammatory response. Obesity was not associated with increased pain or analgesic consumption in the first 24 hours after surgery. CONCLUSIONS: Obesity is associated with a proinflammatory state after THA as demonstrated by enhanced cytokine reactivity. Larger studies exploring the specific impact of obesity and inflammation on surgical outcomes, including pain, are warranted. LEVEL OF EVIDENCE: Level II, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

A prospective, randomized, controlled trial comparing ultrasound versus nerve stimulator guidance for interscalene block for ambulatory shoulder surgery for postoperative neurological symptoms.

BACKGROUND: Visualization with ultrasound during regional anesthesia may reduce the risk of intraneural injection and subsequent neurological symptoms but has not been formally assessed. Thus, we performed this randomized clinical trial comparing ultrasound versus nerve stimulator-guided interscalene blocks for shoulder arthroscopy to determine whether ultrasound could reduce the incidence of postoperative neurological symptoms. METHODS: Two hundred thirty patients were randomized to a standardized interscalene block with either ultrasound or nerve stimulator with a 5 cm, 22 g Stimuplex insulated needle with 1.5% mepivacaine with 1:300,000 epinephrine and NaCO3 (1 meq/10 mL). A standardized neurological assessment tool (questionnaire and physical examination) designed by a neurologist was administered before surgery (both components), at approximately 1 wk after surgery (questionnaire), and at approximately 4-6 weeks after surgery (both components). Diagnosis of postoperative neurological symptoms was determined by a neurologist blinded to block technique. RESULTS: Two hundred nineteen patients were evaluated. Use of ultrasound decreased the number of needle passes for block performance (1 vs 3, median, P < 0.001), enhanced motor block at the 5-min assessment (P = 0.04) but did not decrease block performance time (5 min for both). No patient required conversion to general anesthesia for failed block, and patient satisfaction was similar in both groups (96% nerve stimulator and 92% ultrasound). The incidence of postoperative neurological symptoms was similar at 1 wk follow-up with 11% (95% CI of 5%-17%) for nerve stimulator and 8% (95% CI of 3%-13%) for ultrasound and was similar at late follow-up with 7% (95% CI of 3%-12%) for nerve stimulator and 6% (95% CI of 2%-11%) for ultrasound. The severity of postoperative neurological symptoms was similar between groups with a median patient rating of moderate. Symptoms were primarily sensory and consisted of pain, tingling, or paresthesias. CONCLUSIONS: Ultrasound reduced the number of needle passes needed to perform interscalene block and enhanced motor block at the 5 min assessment; however, we did not observe significant differences in block failures, patient satisfaction or incidence, and severity of postoperative neurological symptoms.

Clonidine and analgesic duration after popliteal fossa nerve blockade: randomized, double-blind, placebo-controlled study.

BACKGROUND: We tested the hypothesis that 100 microg clonidine added to 0.375% bupivacaine would prolong the duration of analgesia from popliteal fossa nerve blockade. METHODS: Ninety-nine patients scheduled for hospital admission after foot or ankle surgery entered this randomized, double-blind, placebo-controlled trial. Patients received a popliteal fossa block (nerve stimulator technique, via the posterior approach) using 30 mL 0.375% bupivacaine, with epinephrine. Patients were randomized to receive no clonidine, 100 microg clonidine IM, or 100 microg clonidine with bupivacaine for the popliteal block. Patients also received a combined spinal-epidural anesthetic, a saphenous nerve block, and postoperative IV patient-controlled analgesia. The primary outcome was patient-reported duration of analgesia. RESULTS: Duration of analgesia was statistically longer in the block clonidine group (18 +/- 6 h for clonidine with bupivacaine vs 14 +/- 7 h for IM clonidine and 15 +/- 7 h for control, P = 0.016 for control vs clonidine with bupivacaine). Pain scores, analgesic use, and side effects attributable to pain management were similar among groups. CONCLUSIONS: Clonidine significantly prolongs the analgesic duration after popliteal fossa nerve blockade with bupivacaine.

Nerve localization techniques for interscalene brachial plexus blockade: a prospective, randomized comparison of mechanical paresthesia versus electrical stimulation.

Postoperative neurologic symptoms (PONS) are relatively common after upper extremity orthopedic surgery performed under peripheral neural blockade. In this study, we prospectively compared the incidence of PONS after shoulder surgery under interscalene (IS) block using the electrical stimulation (ES) or mechanical paresthesia (MP) techniques of nerve localization. For patients randomized to the MP group, a 1-in, 23-g long-beveled needle was placed into the IS groove to elicit a paresthesia to the shoulder, arm, elbow, wrist, or hand. For patients randomized to the ES group, a 5-cm, 22-g short-beveled insulated needle was placed into the IS groove to elicit a motor response including flexion or extension of the elbow, wrist, or fingers or deltoid muscle stimulation at a current between 0.2 and 0.5 mA. Each IS block was performed with 50-60 mL of 1.5% mepivacaine containing 1:300,000 epinephrine and 0.1meq/L sodium bicarbonate. Two-hundred-eighteen patients were randomized between the two groups. One patient was lost to follow-up. Twenty-five patients (23%) in the ES group experienced paresthesia during needle insertion. The incidence of PONS using the ES technique was 10.1% (11/109), whereas the incidence with the MP technique was 9.3% (10/108) (not significant). The PONS lasted a median duration of 2 mo, and symptoms in all patients resolved within 12 mo. The success rate, onset time, and patient satisfaction were also comparable between groups. We conclude that the choice of nerve localization technique can be made based on the patient's and anesthesiologist's comfort and preferences and not on concern for the development of PONS.

Addition of Dexamethasone and Buprenorphine to Bupivacaine Sciatic Nerve Block: A Randomized Controlled Trial.

BACKGROUND AND OBJECTIVES: Sciatic nerve block provides analgesia after foot and ankle surgery, but block duration may be insufficient. We hypothesized that perineural dexamethasone and buprenorphine would reduce pain scores at 24 hours. METHODS: Ninety patients received ultrasound-guided sciatic (25 mL 0.25% bupivacaine) and adductor canal (10 mL 0.25% bupivacaine) blockade, with random assignment into 3 groups (30 patients per group): control blocks + intravenous (IV) dexamethasone (4 mg) (control); control blocks + IV buprenorphine (150 µg) + IV dexamethasone (IV buprenorphine); and nerve blocks containing buprenorphine + dexamethasone (perineural). Patients received mepivacaine neuraxial anesthesia and postoperative oxycodone/acetaminophen, meloxicam, pregabalin, and ondansetron. Patients and assessors were blinded to group assignment. The primary outcome was pain with movement at 24 hours. RESULTS: There was no difference in pain with movement at 24 hours (median score, 0). However, the perineural group had longer block duration versus control (45.6 vs 30.0 hours). Perineural patients had lower scores for "worst pain" versus control (median, 0 vs 2). Both IV buprenorphine and perineural groups were less likely to use opioids on the day after surgery versus control (28.6%, 28.6%, and 60.7%, respectively). Nausea after IV buprenorphine (but not perineural buprenorphine) was severe, frequent, and bothersome. CONCLUSIONS: Pain scores were very low at 24 hours after surgery in the context of multimodal analgesia and were not improved by additives. However, perineural buprenorphine and dexamethasone prolonged block duration, reduced the worst pain experienced, and reduced opioid use. Intravenous buprenorphine caused troubling nausea and vomiting. Future research is needed to confirm and extend these observations.

Addition of pregabalin to multimodal analgesic therapy following ankle surgery: a randomized double-blind, placebo-controlled trial.

BACKGROUND AND OBJECTIVES: Pregabalin is often used as a perioperative analgesic adjunct; some studies show benefit, but others do not. Adverse effects, such as confusion and sedation, have been attributed to perioperative use of pregabalin. We tested the hypothesis that pregabalin, when used as part of a multimodal analgesic regimen, reduces the duration of moderate to severe pain in the first 24 hrs following foot or ankle surgery. Secondary outcomes included measures of opioid and pregabalin adverse effects. METHODS: Sixty patients scheduled for hospital admission after foot or ankle surgery entered this randomized, double-blind, placebo-controlled trial. Patients received a neuraxial anesthetic, a popliteal fossa sciatic nerve block using 30 mL 0.375% bupivacaine with clonidine 100 µg and epinephrine, a saphenous nerve block, postoperative hydromorphone intravenous patient-controlled analgesia, and oral analgesics (oxycodone/acetaminophen). Patients were randomized to receive pregabalin (100 mg preoperatively, then 50 mg every 12 hrs) or a placebo for 3 days. The primary outcome was the number of hours that patients reported moderate to severe pain. RESULTS: Both groups reported a similar number of hours of moderate to severe pain during the first 24 hrs: 4.1 (SD, 4.1) hrs (pregabalin) versus 4.5 (SD, 3.5) hrs (placebo). Pain scores, opioid use, and adverse effects were also similar in both groups. CONCLUSIONS: No clinical benefit was obtained from perioperative administration of pregabalin (100 mg preoperative, then 50 mg every 12 hrs) as part of a multimodal postoperative analgesic regimen following foot and ankle surgery.

Comparison of the transarterial axillary block and the ultrasound-guided infraclavicular block for upper extremity surgery: a prospective randomized trial.

BACKGROUND AND OBJECTIVES: The transarterial axillary block and the ultrasound-guided infraclavicular block are both effective methods of anesthetizing the upper extremity. This study compares these methods with respect to subjective postoperative dysesthesias, block adequacy, patient comfort, and patient satisfaction. METHODS: Two hundred thirty-two patients were randomized to receive an ultrasound-guided infraclavicular block or a transarterial axillary block for upper extremity surgery. Block placement, motor and sensory testing, and block adequacy data were recorded. The subjects were contacted by a blinded research assistant at 2 and 10 days postoperatively to assess for the presence of dysesthesias and pain and to assess patient satisfaction. RESULTS: The 2 techniques were similar with respect to block performance time and adequacy of the block for surgery. There was no significant difference between the blocks in terms of postoperative dysesthesias (23.9% in the axillary group vs 17.1% in the infraclavicular group at 2 days, P = 0.216, and 11.0% vs 6.31% at 10 days, P = 0.214). None of the dysesthesias were permanent. The infraclavicular block had a lower incidence of paresthesias during placement (P = 0.035) and was associated with less pain at the block site (P = 0.010 at 2 days, P = 0.002 at 10 days). More patients were willing to undergo the infraclavicular block as a future anesthetic when compared with the axillary block (P = 0.025 at 10 days). CONCLUSIONS: There is no significant difference between the 2 techniques in terms of adequacy for surgery and subjective postoperative dysesthesias. The ultrasound-guided infraclavicular block is associated with greater patient comfort and willingness to undergo the same anesthetic when compared with the transarterial axillary block.

Similar analgesic effect after popliteal fossa nerve blockade with 0.375% and 0.75% bupivacaine.

This study tested the hypothesis that increasing the concentration of bupivacaine from 0.375 to 0.75% would increase the duration of postoperative analgesia by 3 h. Seventy patients scheduled for hospital admission after foot or ankle surgery gave consent to enter this prospective randomized trial. Patients were randomly assigned to receive a popliteal fossa block (posterior approach) using 30 cc of either 0.375% or 0.75% bupivacaine, with epinephrine. Patients also received a neuraxial anesthetic and postoperative intravenous patient-controlled analgesia. Patient characteristics, duration of analgesia, pain scores, use of analgesic medications, and side effects of analgesic therapy were determined. Duration of analgesia was similar with both concentrations of bupivacaine (0.375% 14 +/- 8 h, 0.75% 13 +/- 6 h; mean +/- SD). Pain scores were the same for both groups on the first postoperative day (3 of 10 at rest, 5 with therapy). Analgesic use and side effects attributable to pain management did not differ between groups. In conclusion, postoperative analgesia was not affected by the concentration of bupivacaine used for the nerve block. There was no benefit to increasing the concentration of bupivacaine above 0.375% for single-injection popliteal fossa nerve blockade when performed for postoperative analgesia.

Assessing sedation with regional anesthesia: inter-rater agreement on a modified Wilson sedation scale.

UNLABELLED: A valid and reliable means for measuring sedation during regional anesthesia would be valuable for both research and practice. Current methods of monitoring sedation include machine-, patient-, and observer-based assessment. The reliability of machine-based methods is limited at lower levels of sedation, whereas patient-based methods are impractical at higher levels. Observer-based methods offer the best alternative for assessing sedation during regional anesthesia; however, their reliability has not been adequately documented. We examined the interrater reliability of the Wilson sedation scale. Sedation was assessed by pairs of anesthesia care providers in 100 patients undergoing surgical procedures with regional anesthesia. On the basis of the findings, the scale was modified, and 50 additional patients were assessed. The study protocol called for a series of standardized stimuli administered by a research assistant. Raters were blinded to each other's ratings. Interrater reliability was assessed by using the kappa statistic, a measure of actual agreement beyond agreement by chance. When continuing checks on its operationalization and reliability are included, the modified Wilson scale provides a simple and reliable means by which to assess and monitor intraoperative sedation. IMPLICATIONS: We evaluated the interrater reliability of the Wilson scale for measuring sedation during regional anesthesia. Paired anesthesia care providers' ratings of patient sedation indicated very good interrater reliability in both the original scale and a modified version. The modified Wilson scale provides a quick noninvasive means of monitoring sedation during regional anesthesia.

Angiotensin-converting enzyme activity: a novel way of assessing pulmonary changes during total knee arthroplasty.

Emboli after tourniquet release (TR) during total knee arthroplasty (TKA) occur in all patients. This may lead to fat embolism syndrome with lung injury. Angiotensin-converting enzyme (ACE) lines the pulmonary endothelium, and a decrease in ACE metabolism or hydrolysis of (3)HBPAP ((3)H-benzoyl-Phe-Ala-Pro; a substrate specific for ACE) has been associated with lung injury. We evaluated the association of this assay with pulmonary changes during TKA. Eleven consecutive patients undergoing bilateral TKA had the ACE assay performed perioperatively. We determined substrate hydrolysis and pulmonary capillary surface area (capillary perfusion index; CPI) and correlated it with pulmonary vascular resistance (PVR) and clinical outcome. Ten of the 11 patients demonstrated an increase in substrate hydrolysis and CPI along with a decrease in PVR after first or second TR when compared with baseline values (P < 0.05). In the other patient, PVR continued to increase even after TR, whereas CPI and substrate hydrolysis decreased after surgery. Whereas all others did well clinically, this patient developed confusion and hypoxemia. In previous studies, a decrease in PVR with an increase in CPI, as exhibited by the 10 patients, has been associated with pulmonary capillary recruitment. We believe this to be an important mechanism by which the lungs are able to accommodate the burden of emboli at the time of TR.