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Background: Peripheral nerve blocks effectively alleviate postoperative pain. Animal studies and human research suggest that opioid tolerance may reduce the effectiveness of local analgesics. The reduced effectiveness has been observed in opioid-tolerant humans and animals undergoing spinal and infiltration anaesthesia with both lidocaine and bupivacaine. However, the impact on peripheral nerve blocks in humans has not been evaluated. This study aims to assess the onset time and duration of a radial nerve block in opioid-tolerant individuals compared to opioid-naive individuals. We hypothesise that peripheral nerve blocks may be less effective in producing sensory and motor blockades in opioid-tolerant individuals compared to their opioid-naive counterparts., Methods: Twenty opioid-tolerant individuals will be matched by sex and age with opioid-naïve counterparts. Participants will receive an ultrasound-guided radial nerve block. The primary outcome is the difference in the duration of sensory nerve blockade between the two groups. The secondary outcomes include the onset time of sensory blockade, onset time of motor blockade, and difference in duration of motor nerve blockade., Conclusion: This study will compare the effectiveness of a peripheral nerve block between opioid-tolerant and opioid-naïve individuals. Any found differences could support a specific postoperative protocol for opioid-tolerant individuals regarding the use of peripheral nerve blocks., (© 2024 The Author(s). Acta Anaesthesiologica Scandinavica published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.)

Background: Prolonging effects of adjuncts to local anaesthetics in peripheral nerve blocks have been demonstrated in randomised clinical trials. The chosen primary outcome and anticipated effect size have major impact on the clinical relevance of results in these trials. This scoping review aims to provide an overview of frequently used outcomes and anticipated effect sizes in randomised trials on peripheral nerve block adjuncts., Methods: For our scoping review, we searched MEDLINE, Embase and CENTRAL for trials assessing effects of adjuncts for peripheral nerve blocks published in 10 major anaesthesia journals. We included randomised clinical trials assessing adjuncts for single-shot ultrasound-guided peripheral nerve blocks, regardless of the type of interventional adjunct and control group, local anaesthetic used and anatomical localization. Our primary outcome was the choice of primary outcomes and corresponding anticipated effect size used for sample size estimation. Secondary outcomes were assessor of primary outcomes, the reporting of sample size calculations and statistically significant and non-significant results related to the anticipated effect sizes., Results: Of 11,854 screened trials, we included 59. The most frequent primary outcome was duration of analgesia (35/59 trials, 59%) with absolute and relative median (interquartile range) anticipated effect sizes for adjunct versus placebo/no adjunct: 240 min (180-318) and 30% (25-40) and for adjunct versus active comparator: 210 min (180-308) and 17% (15-28). Adequate sample size calculations were reported in 78% of trials. Statistically significant results were reported for primary outcomes in 45/59 trials (76%), of which 22% did not reach the anticipated effect size., Conclusion: The reported outcomes and associated anticipated effect sizes can be used in future trials on adjuncts for peripheral nerve blocks to increase methodological homogeneity., (© 2024 The Author(s). Acta Anaesthesiologica Scandinavica published by John Wiley & Sons Ltd on behalf of Acta Anaesthesiologica Scandinavica Foundation.)

Introduction: This protocol describes a systematic review and meta-analysis to evaluate the clinical effects of mixing short- and long-acting local anaesthetics in peripheral nerve blocks. Clinicians often combine short- and long-acting local anaesthetics to achieve a briefer onset time. However, this may come with a prize, namely a shorter total duration of the block, which is of clinical importance., Objective: This systematic review aims to strengthen the knowledge of the clinical effects associated with this practice. The primary outcome is the duration of block analgesia. Secondary outcomes are block onset time, sensory and motor block duration. Exploratory outcomes are postoperative pain scores, cumulative 24-h opioid consumption and the prevalence of serious adverse events., Methods: We will conduct a meta-analysis of the extracted data, and the risk of bias for each study will be evaluated. We will perform a Trial Sequential Analysis, subgroup, and sensitivity analyses and assess the overall risk of publication bias. Finally, we will evaluate the review using the GRADE principles., (© 2023 Acta Anaesthesiologica Scandinavica Foundation.)

Background: Infants and children require a larger dose of a local anaesthetic (LA) to establish epidural analgesia than adults, but the reason for this remains unclear. We hypothesised that prominent ventro-dorsal expansion of the epidural space limits cranio-caudal spread of LA in infants. Accordingly, we studied the dimensions of the epidural space with real-time ultrasound (US) before and after epidural injection., Methods: Ninety-six infants and children aged 0-12 years who underwent abdominal surgery under combined epidural and general anaesthesia were examined in this prospective observational study. Using a micro-convex probe, US recordings of the posterior epidural space were performed while a LA (0.5 ml kg -1 ) was infused at 0.54 ml s -1 . The width in the ventro-dorsal dimension (VDD) of the posterior epidural space before and after injection was recorded; the change in VDD was defined as "ballooning". Correlations between "ballooning" and patient age, body mass index, and volume and rate of LA administration were analysed., Results: "Ballooning" correlated positively but weakly with age (R 2  = 0.25; p < .001) and the infused LA volume (R 2  = 0.32; p < .001). The "magnitude of ballooning" ("ballooning" per ml of injected LA) correlated negatively but weakly with age (R 2  = 0.27; p < .001)., Conclusions: "Magnitude of ballooning" of the epidural space become inconspicuous with growing during epidural injection. This effect may slow the cranio-caudal spread of LA and explain partially why larger volumes of LA are required to effect a block in children., (© 2021 Acta Anaesthesiologica Scandinavica Foundation.)

Background: Management of moderate-to-severe post-operative pain after elective caesarean section (ECS) is internationally primarily based on either epidural catheters or opioids. However, both techniques are associated with some undesirable adverse events. Bilateral transmuscular quadratus lumborum (TQL) block has proven to reduce opioid consumption significantly in the first 24 post-operative hours following ECS and prolong time to first opioid (TFO) (Hansen CKD, Steingrimsdottir M, Laier GE, et al. Reg Anesth Pain Med. 2019; 10.1136/rapm-2019-100540). We present a randomised controlled trial aiming to investigate whether continuous analgesia via bilateral TQL catheters can prolong TFO after ECS., Methods: This study is a double-blind, randomised, placebo-controlled trial. Patients should be 18 years or older and scheduled for ECS under spinal anaesthesia to be included. Main exclusion criteria are inability to cooperate, excessive daily intake of opioids and difficult ultrasound visualisation of muscular and fascial structures. Participants are randomised to receive ultrasound-guided injection of either 30 mL ropivacaine 0.2% bilaterally and an elastomeric pump containing 0.2% ropivacaine, or 30 mL saline bilaterally and an elastomeric pump containing saline, 2 hours after catheter placement. The primary endpoint is TFO. Secondary outcomes include pain intensity on a numeric rating scale (NRS), accumulated morphine consumption during 24 hours, displacement frequency of catheters and morphine-related adverse events., Recruitment Period: Four patients were included from September 2018 to November 2018. Inclusion was resumed in June 2019 and will continue until 24 patients with useful data have been included in the trial. Expected inclusion period is 10-14 months., Trial Registration: ClinicalTrials.gov identifier: NCT03663478. EudraCT: 2017-003625-15., (© 2020 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: The objective of this trial is to optimize the transmuscular quadratus lumborum (TQL) block, by investigating the minimal effective volume (MEV 90 ) of ropivacaine 0.75% for single-shot TQL block in percutaneous nephrolithotomy (PNL) patients., Methods: This double-blind, randomized and controlled dose-finding trial is based on a biased coin up-and-down sequential design, where the volume of local anaesthetic administered to each patient depends on the response from the previous one. Investigating the TQL block, the first patient recruited receives 20 ml ropivacaine 0.75% preoperatively. In case of block failure, the next patient will receive the same volume with an increment of 2 ml. Given a successful block for the first patient, the next patient will be randomized to either a lower volume (previous volume with a reduction of 2 ml), or the same volume as the previous patient. The respective probabilities being b = 0.11 for a reduced volume and 1-b = 0.89 for the same volume. Block success is defined as patient reported pain score numeric rated scale (NRS) ≤3 (0-10/10) 30 minutes after arrival in the post anaesthesia care unit (PACU). The NRS pain score is our primary and only outcome for block success. A minimum of 25 eligible patients are needed to achieve precise estimation of MEV 90 with narrow 95% confidence intervals derived by bootstrapping., Discussion: Recruiting will begin June 2020 and is expected to finish November 2020. Data analysis will be performed at interims during and after the study. Results will be published in an international peer-reviewed medical journal., (© 2020 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: A femoral nerve block relieves pain after total hip arthroplasty, but its use is controversial due to motor paralysis accompanied by an increased risk of fall. Assumedly, the iliopsoas plane block (IPB) targets the hip articular branches of the femoral nerve without motor blockade. However, this has only been indicated in a cadaver study. Therefore, we designed this volunteer study., Methods: Twenty healthy volunteers were randomly allocated to blinded paired active vs. sham IPB (5 mL lidocaine 18 mg/mL with epinephrine vs saline). The primary outcome was reduction of maximal force of knee extension after IPB compared to baseline. Secondary outcomes included reduction of maximal force of hip adduction, and the pattern of injectate spread assessed with magnetic resonance imaging., Results: Mean (confidence interval) change of maximal force of knee extension from baseline to after IPB was -9.7 N (-22, 3.0) (P = .12) (n = 14). The injectate was consistently observed in an anatomically well-defined closed fascial compartment between the intra- and extra-pelvic components of the iliopsoas muscle anterior to the hip joint., Conclusion: We observed no significant reduction of maximal force of knee extension after an IPB. The injectate was contained in a fascial compartment previously shown to contain all sensory branches from the femoral nerve to the hip joint. The clinical consequence of selective anesthesia of all sensory femoral nerve branches from the hip could be a reduced risk of fall compared to a traditional femoral nerve block. Registration of Trial: The trial was prospectively registered in EudraCT (Reference: 2018-000089-12, https://www.clinicaltrialsregister.eu/ctr-search/search?query=2018-000089-12)., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: The reported variation in nerve block duration is considerable. To individualize nerve block therapy, knowledge of the intra- vs inter-individual variability is essential. We investigated the relative contribution of these 2 parameters to the overall nerve block duration variability., Methods: With ethics committee approval, we conducted a randomized cross-over trial where 20 healthy volunteers received 8 common peroneal nerve blockades with lidocaine 0.5% on 4 consecutive days. Allocations were 5 mL to either the right or left side and 10 mL to the opposite side on day 1 and 2 and vice versa on day 3 and 4. With fixed needle entry and nerve target, we repeated local anaesthetic deposition for each blockade. The primary outcome was variation in duration of sensory nerve block defined as insensitivity to a cold stimulus. Data were analysed using linear mixed model regression., Results: The mean sensory block duration of 380 (95% CI = [342; 418]) minutes on day one was 55 [33; 77] minutes longer than on day two (P < .001), but there were no differences in mean duration between days 2, 3 and 4. The ratios with 2.5; 97.5 percentiles between inter- and intra-individual variation were 2.4 [0.8; 5.2] for the 5 mL blockades and 3.0 [0.9; 6.7] for the 10 mL blockades. The probabilities of inter- to intra-individual variation-ratios >1 were 96% and 97%., Conclusion: The intra-individual variability is a substantially minor contributor to the overall variability in sensory nerve block duration compared with the inter-individual variability., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Sciatic nerve blocks are used for many orthopaedic procedures on the knee, lower leg, foot and ankle. However, as nerve block durations vary considerably, the timing of supplemental analgesia is challenging. Therefore, knowledge on the effect of local anaesthetic (LA) dose on block duration is important to outweigh the benefits of increasing LA dose against the risk of LA systemic toxicity. In this randomized, double-blind trial, we aimed to explore the relationship between the volume of ropivacaine 0.2% and sciatic nerve block duration. We hypothesized that increasing LA volume would prolong block duration., Methods: We randomized 60 healthy volunteers to receive one of five volumes of ropivacaine 0.2%: 5, 10, 15, 20, or 30 mL. We used an ultrasound-guided, catheter-based technique targeting the sciatic nerve in the infragluteal region. The primary outcome was sensory block duration defined as the time of insensitivity to a cold stimulus. Intergroup differences were tested using one-way ANOVA., Results: Mean (SD) sensory block durations for the tibial nerve (TN) with increasing volume were: 9.3 hours (1.7), 10.4 hours (1.6), 9.7 hours (2.9), 10.7 hours (2.8) and 9.9 hours (2.6). Mean (SD) sensory block durations for the common peroneal nerve (CPN) were: 10.6 hours (2.7), 11.9 hours (1.5), 11.0 hours (3.3), 13.2 hours (3.7), and 13.5 hours (6.1). There were no intergroup differences (P = .67 [TN]; P = .25 [CPN])., Conclusion: We found no effect of increasing the volume of ropivacaine 0.2% from 5 to 30 mL on sensory sciatic nerve block duration., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Post-operative pain after an above-knee amputation is often severe, and in the elderly patients the adverse effects of post-operative opioids are evident. We hypothesized that continuous perineural local anesthetic infusion (CPI) combined to a wound infusion will reduce acute pain and opioid consumption compared to placebo after above knee amputation., Methods: Ninety-three patients going through an above knee amputation were recruited for this randomized, controlled trial. Two catheters were placed, one to the sciatic nerve sheath and one under the fasciae during the amputation. After two 10 mL boluses of ropivacaine 0.75% a post-operative infusion of ropivacaine 0.2% or placebo (NaCl 0.9%) at 2 mL/h was administered for 72 hours to both catheters. The primary outcome was average stump pain during the first 5 days., Results: The mean intensity of stump pain during the first five post-operative days was 1.4 (0.8) in the CPI group and 1.9 (0.9) in the placebo group on VRS, mean (SD), P = .006. The opioid consumption on first five post-operative days did not differ between the groups., Conclusion: A combination of continuous perineural and wound local anesthetic infusion seems to diminish the intensity of stump pain after above knee amputation., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Postoperative inflammation is a common consequence of surgery and the ensuing stress response. Local anesthetics have anti-inflammatory properties. The primary aim of this study was to evaluate if LA administrated intraperitoneally perioperatively might inhibit expression of inflammatory cytokines., Methods: This was a, randomized, double blind, placebo-controlled study (ClinicalTrial.gov reg no: NCT02256228) in patients undergoing surgery for ovarian cancer. Patients were randomized to receive: intraperitoneal ropivacaine (Group IPLA) or saline (Group P) perioperatively. Except for study drug, patients were treated similarly. At the end of surgery, a multi-port catheter was inserted intraperitoneally, and ropivacaine 2 mg/mL or 0.9% saline, 10 mL was injected intermittently every other hour during 72 hours postoperatively. Systemic expression of cytokines and plasma ropivacaine were determined before and 6, 24, and 48 hours after surgery. Stress response was measured by serum glucose, cortisol, and insulin., Results: Forty patients were recruited, 20 in each group. There was no statistical significant difference in systemic cytokine between the groups at any time point. Serum cortisol was significantly lower in the IPLA group at 6 hours, median 103 nmol/L (IQR 53-250) compared to placebo, median 440 nmol/L (IQR 115-885), P = 0.023. Serum glucose and insulin were similar between the groups. Total and free serum concentrations of ropivacaine were well below toxic concentrations., Conclusion: In this small study, perioperative intraperitoneal ropivacaine did not reduce the systemic inflammatory response associated with major abdominal surgery. Total and free ropivacaine concentrations were below known toxic concentrations in humans., (© 2019 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: We performed a randomised blinded pilot study in 16 healthy volunteers to assess whether placing a suture-method catheter in the adductor canal is feasible with two different insertion techniques., Methods: Each volunteer had a suture-method catheter placed approximately halfway between the superior anterior iliac spine and base of the patella in both legs. Catheters were placed using a parallel technique in one leg and a perpendicular technique in the other leg, according to randomisation. 15 mL lidocaine 1% was injected in each catheter. Successful placement was defined as loss of cold sensation in the saphenous area 30 min after injection. Volunteers were sent home and returned the following day and another dose of lidocaine (15 mL, 1%) was injected through the catheters. Catheter displacement distance was assessed by ultrasound and cold sensation was assessed. In case of preserved cold sensation, we attempted to reposition the catheter with a subsequent injection of lidocaine and reassessment of cold sensation., Results: All primary placements were successful using the perpendicular approach (100%; 95% CI 81%-100%) whereas one placement failed using the parallel approach (94%; 95% CI 72%-99%). Three catheters placed using the perpendicular approach were displaced on day 2, compared to one catheter placed with the parallel approach. Displacement distance was highly variable. All catheters, except one, could be repositioned. Three volunteers reported transient sensory deficits lasting approximately 6-8 weeks., Conclusion: The suture-method catheter can be placed in the adductor canal with high success rates for initial placement with both techniques., (© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Thoracic epidural analgesia (TEDA) was offered to patients with refractory angina pectoris. Our primary objectives were to evaluate TEDAs´ influence on quality of life (QoL, base for power analysis), and hypothesising that TEDA with bupivacaine during 1 month counteracts exercise-induced myocardial hypoperfusion and increase physical performance., Methods: Patients with refractory angina and exercise inducible hypoperfusion, as demonstrated by myocardial perfusion imaging (MPI), were randomised to 1-month treatment with TEDA with bupivacaine (B-group, n = 9) or saline (P-group, n = 10) in a double-blind fashion. MPI and bicycle ergometry were performed before TEDA and after 1 month while subjective QoL on a visual analogue scale (VAS) reported by the patients was checked weekly., Results: During this month VAS (mean [95%CI]) increased similarly in both groups (B-group from 33 [18-50] to 54 [30-78] P < 0.05; P-group from 40 [19-61] to 48 [25-70] P < 0.05). The B-group reduced their exertional-induced myocardial hypoperfusion (from 32% [12-52] to 21% [3-39]; n = 9; P < 0.05), while the P-group showed no significant change (before 21% [6-35]; at 1 month 23% [6-40]; n = 10). MPI at rest did not change and no improvement in physical performance was detected in neither of the groups., Conclusions: In refractory angina, TEDA with bupivacaine inhibits myocardial ischaemia in contrast to TEDA with saline. Regardless of whether bupivacaine or saline is applied intermittently every day, TEDA during 1 month improves the quality of life and reduces angina, even when physical performance remains low. A significant placebo effect has to be considered., (© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: We recently showed that the novel combination of a superficial cervical plexus block, a suprascapular nerve block, and the lateral sagittal infraclavicular brachial plexus block (LSIB) provides an alternative anaesthetic method for arthroscopic shoulder surgery. In this study, we hypothesised that the LSIB dose for this shoulder block could be significantly reduced by injecting only towards the shoulder relevant posterior and lateral cords. Our aim was to determine the minimum effective volume in 50% of the patients (MEV 50 ) and to estimate the MEV 95, when using ropivacaine 7.5 mg/mL to block these cords., Methods: Twenty-three adult patients scheduled for hand surgery participated in the study. Considering the artery as a clock face with 12 o'clock ventral, the designated volume was injected immediately outside the arterial wall and between 8 and 9 o´clock. The in-plane technique was used. Block success was assessed 30 minutes after withdrawal of the needle. Successful posterior cord block was defined as anaesthesia or analgesia of the axillary nerve. Successful lateral cord block was defined as either anaesthesia or analgesia, or >50% motor block of the musculocutaneous nerve. MEV 50 was determined by the staircase up-and-down method. Logistic regression and probit transformation were applied to estimate MEV 95 ., Results: MEV 50 and MEV 95 were 7.8 mL [95% confidence interval (CI), 7.3-8.4] and 9.0 mL (95% CI, 7.8-10.3), respectively., Conclusion: For single-deposit infraclavicular posterior and lateral cord block, the MEV 95 of ropivacaine 7.5 mg/mL was estimated to 9.0 mL., (© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Various adjuvants have been tried to improve quality and increase duration of local anaesthetics during various nerve blocks. We aimed to evaluate the effect of adding midazolam to bupivacaine on rectus sheath (RS) block in patients undergoing umbilical or epigastric hernia repair., Methods: In all, 60 adult patients were divided into two equal groups, each group included 30 patients. Group I received 20 ml of bupivacaine hydrochloride 0.25% + midazolam 50 μg/kg in 2 ml saline 0.9% (Midazolam group, n = 30), whereas Group II received 20 ml of bupivacaine hydrochloride 0.25% + 2 ml saline (Control group, n = 30) for RS block on each side. The primary outcome was post-operative 48 h morphine consumption, whereas secondary outcomes included analgesia duration, post-operative pain, as evaluated by visual analogue scale (VAS) for pain scoring at 1, 2, 6, 12, 24 and 48 h post-operatively, reported post-operative nausea and or vomiting (PONV), somnolence or any adverse drug reactions., Results: The current study showed that addition of midazolam to bupivacaine for RS blockade provided good analgesia as evidenced by a statistically significant less morphine consumption in the post-operative 48 h [11.2 (5.3-18.3) vs. 25.9 (15.2-31.0) mg, P = 0.002], longer duration of analgesia, lower VAS during post-operative 48 h, lower incidence of PONV, somnolence and pruritus., Conclusion: Midazolam addition to bupivacaine for RS blockade provided adjuvant analgesia as supported by less morphine consumption, longer duration of analgesia, and lower VAS score., (© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Brachial plexus block is often utilised for proximal arm arteriovenous access creation. However, the medial upper arm and axilla are often inadequately anaesthetised, requiring repeated, intraoperative local anaesthetic supplementation, or conversion into general anaesthesia. We hypothesised that the addition of a PECS II block would improve anaesthesia and analgesia for proximal arm arteriovenous access surgery., Methods: In this prospective, double-blinded, randomised proof-of-concept study, 36 consenting adults with end-stage renal disease aged between 21 and 90 years received either a combined supraclavicular and PECS II block (Group PECS, n = 18), or combined supraclavicular and sham block (Group SCB, n = 18) for proximal arm arteriovenous access surgery. Primary outcome was whether patients required intraoperative local anaesthetic supplementation by the surgeon., Results: In Group PECS, 33.3% (6/18) needed local anaesthetic supplementation vs. 100% (18/18) in Group SCB. Group SCB had three times (RR 3.0, 95% CI 1.6-5.8; P < 0.001) the risk of requiring intraoperative local anaesthetic supplementation. Group PECS required lower volume of supplemental local anaesthetic compared to Group SCB (0.0 ml, IQR 0.0-6.3 ml vs. 15.0 ml, IQR 7.4-17.8 ml; P < 0.001). Group SCB had twice [RR 2.2, 95% CI 1.1-4.4; (P = 0.019)] the risk of needing additional sedation or analgesia. There were no significant differences between the groups with respect to postoperative visual analogue scale pain scores, time to first rescue analgesia or patient satisfaction., Conclusion: The results suggest that adding a PECS II block to a supraclavicular block improves regional anaesthesia for patients with end-stage renal disease undergoing proximal arm arteriovenous access surgery., (© 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Ultrasound-guided interscalene nerve block with ropivacaine as local anesthetic agent given as boluses or continuous infusion is the preferred pain management after major shoulder surgery. The use of automated intermittent boluses has been shown to be superior to continuous infusion in sciatic and epidural nerve block., Hypothesis: Automated intermittent boluses reduce pain after major shoulder surgery., Methods: Seventy patients aged 18-75 years, scheduled for major shoulder surgery under general anesthesia with interscalene nerve block were included in this randomized controlled trial. Patients were allocated to either automated intermittent boluses with 16 mg ropivacaine every 2 h combined with patient-controlled administration or to a conventional regimen of continuous infusion of 8 mg/h (4 ml/h) of ropivacaine combined with patient controlled administration (2 ml, lockout time 30 min). Pain (Visual Analog Scale, VAS) was assessed every 8 h postoperatively., Results: Fifty-seven patients completed the study, 29 in the continuous infusion group and 28 in the automated intermittent bolus group. Shoulder arthroplasty was performed in 49 (86%) of the cases. There were no significant differences in VAS score from 8 to 48 h post-operatively. No significant difference in opioid usage was observed. The automated intermittent bolus group reported significantly less force on coughing and more hoarseness. A significantly lower volume of ropivacaine was used in the automated intermittent bolus group., Conclusion: Automated intermittent boluses did not reduce pain or rescue opioid consumption compared with continuous infusion of ropivacaine. The automated intermittent bolus group had significantly less force on coughing and more hoarseness., (© 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Post-operative pain is common and often severe after open abdominal hysterectomy, and analgesic consumption high. This study assessed the efficacy of local infiltration analgesia (LIA) injected systematically into different tissues during surgery compared with saline on post-operative pain and analgesia., Methods: Fifty-nine patients were randomized to Group LIA (n = 29) consisting of 156 ml of a mixture of 0.2% ropivacaine + 30 mg ketorolac + 0.5 mg (5 ml) adrenaline, where the drugs were injected systematically in the operating site, around the proximal vagina, the ligaments, in the fascia and subcutaneously, or to saline and intravenous ketorolac, Group C (Control, n = 28), in a double-blind study. Post-operative pain, analgesic consumption, side-effects, and home discharge were analysed., Results: Median dose of rescue morphine given 0-24 h after surgery was significantly lower in group LIA (18 mg, IQR 5-25 mg) compared with group C (27 mg, IQR 15-43 mg, P = 0.028). Median time to first analgesic injection was significantly longer in group LIA (40 min, IQR 20-60 min) compared with group C (20 min, IQR 12-30 min, P = 0.009). NRS score was lower in the group LIA compared with group C in the direct post-operative period (0-2 h). No differences were found in post-operative side-effects or home discharge between the groups., Discussion: Systematically injected local infiltration analgesia for pain management was superior to saline in the primary endpoint, resulting in significantly lower rescue morphine requirements during 0-24 h, longer time to first analgesic request and lower early post-operative pain intensity., (© 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Although considered safe, no pharmacokinetic data of high dose, high volume local infiltration analgesia (LIA) with ropivacaine without the use of a surgical drain or intra-articular catheter have been described. The purpose of this study is to describe the maximum total and unbound ropivacaine concentrations (C max , C u max ) and corresponding maximum times (T max , T u max ) of a single-shot ropivacaine (200 ml 0.2%) and 0.75 mg epinephrine (1000 μg/ml) when used for LIA in patients for total knee arthroplasty., Methods: In this prospective cohort study, 20 patients were treated with LIA of the knee for primary total knee arthroplasty. Plasma samples were taken at 20, 40, 60, 90, 120, 240, 360 min and at 24 h after tourniquet release, in which total and unbound ropivacaine concentrations were determined., Results: Results are given as median [IQR]. Highest ropivacaine concentration (C max ) was 1.06 μg/ml [0.34]; highest unbound ropivacaine concentration (C u max ) was 0.09 μg/ml [0.05]. The corresponding time to reach the maximum concentration for total ropivacaine was 312 min [120] after tourniquet release, and for the unbound fraction 265 [110] min after tourniquet release., Conclusion: Although great inter-individual variability was found between the maximum ropivacaine concentrations, both maximum total and unbound serum concentrations of ropivacaine remained well below the assumed systemic toxic thresholds of 4.3 and 0.56 μg/ml., (© 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background & Objectives: Most anesthesiologists use the injection of a test dose of local anesthetic in order to evaluate the final needle tip position. Thus, the intraneural injection of a full dose can be avoided. The aim of this study was to analyze whether an intraneural injection of a test dose of bupivacaine could trigger histological changes., Methods: Intraneural injections under direct vision were performed in 40 brachial plexus nerves in seven anesthetized pigs. Tibial nerves served as positive and negative controls. Two milliliter of bupivacaine 0.5% was injected in three nerves on the left brachial plexus. For control of local anesthetic's toxicity Ringer's solution was applied intraneurally on the right side. After maintaining 48 h of general anesthesia, the nerves were resected. The specimens were processed for histological examination and assessed for inflammation (hematoxylin and eosin stain, CD68-immunohistochemistry) and myelin damage (Kluver-Barrera stain). The degree of nerve injury was rated on a scale from 0 (no injury) to 4 (severe injury)., Results: Statistical analysis showed no significant differences between the bupivacaine group [median (interquartile range) 1 (1-1.5)] and the Ringer's solution group [1 (0.5-2) P = 0.772]. Mild myelin alteration was found in 12.5% of all specimens following intraneural injection, irrespective of the applied substance., Conclusions: "In our experimental study, intraneural injection of 2 ml of bupivacaine or Ringer's solution showed comparable mild inflammation. Nevertheless, inflammation can only be prevented by strictly avoiding nerve perforation followed by intraneural injection, as mechanical nerve perforation is a key factor for evolving inflammation., (© 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Continuous femoral nerve block (cFNB) induces quadriceps muscle weakness, but patient-controlled femoral nerve block (PCFNB) can provide analgesia with lower consumption of local anesthetics compared to cFNB. We hypothesized that cFNB followed by PCFNB leads to accelerated recovery of quadriceps weakness after total knee arthroplasty compared to cFNB alone. Secondary outcomes were local anesthetic consumption, pain, and mobilization., Methods: Fifty-six subjects received post-operative cFNB for 24 h and then randomized to receive either cFNB (basal infusion of 6 ml/h using a dummy bolus button; n = 27) or PCFNB (bolus infusion of 3 ml with a lockout time of 30 min and no basal infusion; n = 29) using 0.08% levobupivacaine for the subsequent 24 h in a double-blind manner (registration: UMIN000010105). Quadriceps strength was assessed using a hand-held dynamometer. The percentage change from baseline was compared between groups., Results: Quadriceps strength at 48 h was 47.3 ± 18.3% in the cFNB group and 49.7 ± 15.7% in the PCFNB group (95% confidence interval -7.0-11.9%, P = 0.61). Local anesthetic consumption during the post-operative period was significantly lower in the PCFNB group compared to the cFNB group (102 ± 10.8 ml vs.146 ± 4.6 ml; P < 0.001). No significant differences were found in any of the other outcomes, including pain scores at rest and during knee rehabilitation., Conclusion: Continuous femoral nerve block followed by PCFNB does not improve quadriceps strength recovery time compared to cFNB alone after total knee arthroplasty, but similar analgesic effects were demonstrated with reduced levobupivacaine consumption., (© 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background and Objectives: Transversus abdominis plane block (TAP) and intravenous lignocaine are two analgesic techniques frequently used after abdominal surgery. We hypothesized that these two techniques improve post-operative analgesia after open prostate surgery and sought to compare their efficacy on immediate post-operative outcome after open prostate surgery., Methods: After ethics committee approval, 101 patients were enrolled in this prospective study and randomly allocated to receive bilateral ultrasound-guided TAP (n = 34), intravenous lignocaine (n = 33) or placebo (n = 34). In addition, intravenous paracetamol was given every 6 h. The primary endpoint was the cumulative opioid consumption during the first 48 post-operative hours (median[IQR]). Secondary endpoints included pain scores at rest and upon coughing, need for rescue tramadol, incidence of post-operative nausea and vomiting (PONV), recovery of bowel function and incidence of bladder catheter-related discomfort., Results: Cumulative piritramide consumption after 48 h was 28 [23] mg in the control group, 21 [29] mg in the TAP group and 21 [31] mg in the lignocaine group (P = 0.065). There was no significant difference in post-operative pain scores between groups. The proportions of patients requiring rescue tramadol, experiencing PONV or bladder catheter-related discomfort were similar in each group. Recovery of bowel function was also similar in the three groups., Conclusions: Our study suggests that TAP block and intravenous lignocaine do not improve the post-operative analgesia provided by systematic administration of paracetamol after open prostatectomy., (© 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Ropivacaine is frequently used for local anesthesia in the clinic and is metabolized by cytochrome P450 (CYP450) in the liver. CYP450 polymorphisms may alter the therapeutic efficacy of drugs in patients. In this study, we selected six CYP450 polymorphisms from the dbSNP and HapMap databases, using a combination of functional analysis and Tag SNP strategies and examined these polymorphisms for association with the efficacy of epidural ropivacaine in patients during mastectomy., Methods: A total of 256 patients with breast cancer received thoracic epidural anesthesia with ropivacaine for elective mastectomy with axillary lymph node clearance. Blood samples from patients were genotyped using the SNaPshot method., Results: We found that patients with rs11636419 AG and GG genotypes required lower doses of epidural ropivacaine than patients with the AA genotype (corrected P = 0.024 and P < 0.001, respectively). Similarly, patients with rs17861162 CG and GG genotypes required lower doses of epidural ropivacaine than those with the CC genotype (corrected P = 0.018 and P < 0.001, respectively). There was no statistically significant association between the other four single nucleotide polymorphisms (SNPs) and total or mean ropivacaine dose, the onset of ropivacaine, or the initial dose of lidocaine., Conclusions: Our present data demonstrate that CYP1A2 SNPs rs11636419 and rs17861162 alter the sensitivity of epidural ropivacaine in patients undergoing breast cancer surgery. As such, detection of these two CYP1A2 SNPs may aid in the development of effective personalized treatments for breast cancer patients., (© 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: The use of interscalene catheters is an effective treatment strategy for children and adolescents undergoing shoulder surgery. Although placement of interscalene catheters in the awake child is challenging, some have cautioned against performing regional anesthesia in the patient under general anesthesia. We present a case series of 154 interscalene catheters placed in pediatric patients under general anesthesia and managed in the outpatient setting., Methods: A total of 154 interscalene catheters were placed at a single institution between April 2006 and December 2011 using a modified lateral approach. All catheters were placed with the patient under general anesthesia. The patients discharged home with the catheters were followed-up with daily phone calls until removal of the catheter., Results: Of the 154 patients with an interscalene CPNB, 132 (85.7%) were discharged home with the interscalene CPNB in place. The success rate for the catheters was 92.1% (CI: 86.9-95.7%). The most common reason for catheter failure (6%) was early dislodgement (within 24 h). In addition to these 12 patients, 3 other patients had adverse events related to the interscalene CPNB., Conclusion: Interscalene catheter placement under general anesthesia and management on an outpatient basis is feasible in the pediatric population and is associated with a low rate of catheter-related complications., (© 2015 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Wound infiltration at the end of carotid endarterectomy under general anaesthesia is a simple technique that can be delegated to the surgeon. It was hypothesised that this technique could improve early post-operative analgesia by reducing the need for post-operative opioids., Methods: Forty patients underwent carotid endarterectomy under general anaesthesia with desflurane and remifentanil supplemented with morphine for post-operative analgesia. In a prospective double-blinded randomised study, patients were allocated pre-operatively to receive either subcutaneous infiltration of both wound edges with 20 ml of 0.75% ropivacaine or infiltration with isotonic saline. The primary outcome was morphine consumption while in the post-anaesthesia care unit (PACU). Pain scores at rest and movement, sedation, and patient satisfaction were the other main outcomes used to assess post-operative analgesia., Results: The median dose of morphine administered in the PACU was 2 mg [0-3] in the ropivacaine vs. 4 mg [3-6] in the placebo group (P = 0.0004, Mann-Whitney's test). Pain at rest and at movement was lower in the ropivacaine group throughout observation in the PACU. No difference was found for both pain and opioid consumption after discharge from the PACU or for patient satisfaction. Sedative events in the early post-operative period were less frequent in the ropivacaine group., Conclusions: Local anaesthetic wound infiltration performed before closure reduces the need for additional opioids, lowers the immediate post-operative pain and improves alertness. These results argue for the use of local infiltration anaesthesia for carotid endarterectomy., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

The objective of this review was to systematically assess the effect of thoracic epidural analgesia (TEA) vs. systemic analgesia (SA) on the recovery of gastrointestinal (GI) function in patients following GI surgery. We performed a comprehensive literature search to identify randomized controlled trials of adult patients undergoing GI surgery, comparing the effect of two postoperative analgesia regimens. Patients postoperatively receiving local anesthesia-based TEA with or without opioids were compared to patients receiving opioid-based SA. The outcomes considered were times to GI function recovery, GI complications, and specific side effects. Twelve studies with 331 patients in the TEA group and 319 in the SA group were included. Compared to SA, TEA improved the GI recovery after GI procedures by shortening the time to first passage of flatus by 31.3 h, 95% confidence intervals (CIs): -33.2 to -29.4, P < 0.01; and shortening the time to first passage of stool by 24.1 h, 95% CIs: -27.2 to -20.9, P < 0.001. There was no difference between the groups in the incidence of anastomotic leakage and ileus. The occurrence of postoperative hypotension was relatively higher in the TEA group, risk ratio: 7.9, 95% CIs: 2.4 to 26.5, P = 0.001; other side effects (such as pruritus and vomiting) were similar in the two groups. There is evidence that TEA (compared to SA) improves the recovery of GI function after GI procedures without any increased risk of GI complications. To further confirm these effects, larger, better quality randomized controlled trials with standard outcome measurements are needed., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: We evaluated the analgesic effect of ropivacaine infiltration into the surgical wound after caesarean section., Methods: In a double-blind trial, 67 patients who were scheduled for caesarean section under spinal anaesthesia were randomly assigned to receive either 0.75% ropivacaine or placebo (NaCl 0.9%) through a multi-orifice catheter that was placed into the surgical wound, between the muscle fascia and the subcutaneous tissue. The study drug was administered as a bolus of 10 ml at the end of the operation, followed by an infusion at 2 ml/h for 48 h. All patients were also given paracetamol and ibuprofen. The primary outcome was the total amount of rescue oxycodone needed during the first 48 h post-operatively. Secondary outcomes included pain and patient satisfaction scores. Analyses were according to intention to treat., Results: The mean (± standard deviation) amount of oxycodone administered during the first 48 h was 47.5 ± 20.9 mg in the ropivacaine group and 57.8 ± 29.4 mg in the placebo group (95% confidence interval for the difference between means, -22.8-2.2 mg; P = 0.10). There were no differences between the groups in pain scores or in patient satisfaction scores., Conclusion: Continuous wound infiltration with ropivacaine did not decrease the need for opioids and had no impact on pain scores or patient satisfaction after caesarean section., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Priapism is a rare complication of epidural anaesthesia, and the pathophysiology is poorly understood. In general, 95% of all priapism episodes are ischemic because of decreased penile blood flow, and therefore requires immediate treatment. A case is reported of a 45-year-old male patient in which a clear relation is demonstrated between continuous thoracic epidural analgesia and priapism after transabdominal nephrectomy. The level of epidural anaesthesia supports the theory that the erection is a consequence of increased penile blood flow, thus a relatively harmless condition. However, confirmation by serial cavernous blood gas analysis or colour duplex ultrasonography is mandatory. Until this hypothesis is confirmed, termination of epidural infusion is advised as a primary treatment., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: We undertook a prospective study of non-obstetric epidurals placed in surgical inpatients at a single teaching hospital to evaluate the incidence of and potential risk factors for major complications of continuous epidural anesthesia., Methods: Demographic information, details of the epidural procedure, and complications (from the pre-anesthetic period through resolution) were recorded for more than 5000 surgical inpatients who underwent continuous epidural anesthesia in our institution between March 2009 and April 2011. The incidence of and risk factors for major complications were evaluated., Results: During the study period, 5083 patients were interviewed and their details were recorded (98% capture rate). Sixty-nine (1.36%) experienced major complications: epidural hematoma in 1 patient (0.02%), post-operative neurologic deficits in 57 patients (1.12%), post-dural puncture headache in 7 patients (0.14%), and systemic local anesthetic toxicity in 4 patients (0.08%). Only one patient had permanent sequelae: unilateral lower limb paresthesia. Identified risk factors for neurologic deficits were as follows: American Society of Anesthesiologists status II-III, siting in the lumbar region, orthopedic and urologic surgery, multiple attempts to site an epidural, paresthesia during insertion, a history of neuraxial anesthesia, and use of patient-controlled epidural analgesia., Conclusions: Serious complications were very rare; only one patient had permanent sequelae, and a single epidural hematoma was diagnosed. Post-operative neurologic deficits were more common, but most complications resolved spontaneously within 3 months and they rarely required intervention., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: We studied the hypothesis that an equal spinal anaesthetic dose administered in the sitting position to patients undergoing post-partum tubal ligation (PPTL) and caesarean section (CS) would yield similar sensory block characteristics and analgesic efficacy., Methods: This prospective, non-randomised trial recruited 20 women undergoing PPTL within 48 h of vaginal delivery and 20 undergoing CS. Spinal anaesthesia comprising intrathecal hyperbaric bupivacaine 12 mg and morphine 100 μg was administered at L3/4 with patients sitting. Our primary end point was the maximal dermatomal sensory block (to cold)., Results: Baseline demographics were comparable, but PPTL patients had greater parity, with mean ± standard deviation 17.54 ± 11.2 h from delivery to spinal anaesthesia, and shorter duration of surgery, 17.54 ± 11.2 vs. 40.3 ± 15.5 min. Similar maximal sensory blocks (to cold) were achieved in group PPTL vs. CS, T4 (T1-T5) vs. T3 (T1-T5), P = 0.104, in comparable times, 8.6 ± 2.6 vs. 7.6 ± 3.0 min, P = 0.267. PPTL patients had significantly faster two-segment block regression (70.7 ± 23.5 vs. 97.6 ± 23.9 min, P = 0.001) and to T10 (120.8 ± 35.6 vs. 145.1 ± 24.3 min, P = 0.016), with less hypotension (25% vs. 65%, P = 0.025) and phenylephrine (20.0 ± 60.6 μg vs. 120.0 ± 119.6 μg, P = 0.005)., Conclusion: The same dose of hyperbaric bupivacaine 12 mg and morphine 100 μg administered in the sitting position to both PPTL and CS parturients yielded similar maximal sensory blocks, but PPTL exhibited faster block regression and less hypotension/vasopressor requirement., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: The aim of this study was to assess the possible difference in the optimal effect site concentration of propofol for conscious sedation during spinal anaesthesia with or without intrathecal fentanyl in patients undergoing urologic surgery. The hypothesis was that intrathecal fentanyl would decrease the effect site concentration of propofol needed for conscious sedation., Methods: Among 43 patients, 23 patients received fentanyl 25 mcg and 20 patients received normal saline in addition to hyperbaric bupivacaine 10 mg during spinal anaesthesia. Propofol was infused at a dose determined by a modified Dixon's up-and-down method. The Cerebral State Index was recorded once target effect site concentration was reached to determine the effect of the successfulness of the conscious sedation., Results: The half maximal effective concentration (EC50) of the effect-site concentration of propofol for sedation was 1.67 ± 0.28 mcg/ml in the control group and 0.87 ± 0.15 mcg/ml in the fentanyl group (P = 0.02). The propofol dose for conscious sedation during spinal anaesthesia was decreased by 48% when intrathecal fentanyl 25 mcg was added to local anaesthetics., Conclusion: The EC50 of the effect-site concentration of propofol for sedation decreased from 1.67 ± 0.28 mcg/ml to 0.87 ± 0.15 mcg/ml with the addition of 25 mcg fentanyl to a spinal anaesthetic in patients undergoing urologic surgery., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: This prospective, observer-blinded, randomised, multicentre study aimed at determining the non-inferiority of 50 mg of plain 1% 2-chloroprocaine vs. 10 mg of 0.5% plain bupivacaine in terms of sensory block onset time at T10 after spinal injection. The study hypothesis was that the difference in onset times of sensory block to T10 between the two drugs is ≤ 4 min., Methods: One hundred and thirty patients undergoing lower abdominal or lower limb procedures (≤ 40 min) were randomised to receive one of two treatments: 50 mg of plain 1% 2-chloroprocaine (Group C, n = 66) or 10 mg of plain 0.5% bupivacaine (Group B, n = 64). Times to sensory and motor block onsets, maximum sensory block level, readiness for surgery, regression of sensory and motor blocks, first analgesic requirements, unassisted ambulation, home discharge, and side effects after 24 h and 7 days were registered blindly., Results: Chloroprocaine was comparable with plain 0.5% bupivacaine in terms of time to sensory block at T10 level. Group C showed faster onsets of motor block (5 vs. 6 min), maximum sensory block level (8.5 vs. 14 min), resolution of sensory (105 vs. 225 min) and motor (100 vs. 210 min) blocks, unassisted ambulation (142.5 vs. 290.5 min), first analgesic requirement (120 vs. 293.5 min), and home discharge (150 vs. 325 min) (all comparisons, P < 0.05). No chloroprocaine patient developed transient neurological symptoms., Conclusion: Spinal anaesthesia with 50 mg of plain 1% 2-chloroprocaine is similar to 10 mg of plain 0.5% bupivacaine in terms of onset of sensory block at T10 but shows quicker recovery from anaesthesia than with 0.5% bupivacaine., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Wound infiltration with local anaesthetics is commonly used during breast surgery in an attempt to reduce post-operative pain and opioid consumption. The aim of this review was to evaluate the effect of wound infiltration with local anaesthetics compared with a control group on post-operative pain after breast surgery., Methods: A systematic review was performed by searching PubMed, Google Scholar, the Cochrane database and Embase for randomised, blinded, controlled trials of wound infiltration with local anaesthetics for post-operative pain relief in female adults undergoing breast surgery. The analgesic effect was evaluated in a qualitative analysis by assessment of significant difference between groups (P < 0.05) in pain scores and supplemental analgesic consumption., Results: Ten trials including 699 patients were included in the final analysis. Three trials investigated mastectomy, four trials partial or segmental mastectomy, and three trials breast reduction, excision of benign lump and unspecified breast surgery, respectively. Six trials demonstrated a small and short-lasting, but statistically significant reduction of post-operative pain scores, and four trials observed a statistically significant reduction in post-operative, supplemental opioid consumption that was, however, of limited clinical relevance., Conclusion: Wound infiltration with local anaesthetics may have a modest analgesic effect in the first few hours after surgery. Pain after breast surgery is, however, generally mild to moderate, and other non-invasive analgesic methods may be preferable in this surgical population., (© 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Thoracic epidural infusion analgesia is optimised by using a triple component infusion containing a local anaesthetic, an opioid, and adrenaline. Adrenaline in solution is prone to oxidation, and stabilisers, such as antioxidants (e.g. sulphites) or chelators (edetates), are therefore commonly added. Sulphites may, however, have unwanted effects, especially allergic reactions. The aim of this study was to evaluate the stability of an analgesic infusion solution for epidural administration free of sulphites, containing adrenaline, fentanyl, bupivacaine, and disodium edetate., Methods: An epidural infusion solution containing adrenaline 2 μg/ml, fentanyl 2 μg/ml, bupivacaine 1 mg/ml, and disodium edetate 0.18 μg/ml was stored at 2-8°C for 4.5 months. A concentrate 11 times more potent, used for the production of the ready-to-use solution, was stored at 2-8°C for 9 months. Concentrations of the active ingredients were determined, pH was measured throughout the period, the clarity of the solutions was investigated, and the weight of the infusion bags recorded., Results: After 4.5 months at 2-8°C, the infusion solution contained adrenaline 97.5%, bupivacaine 100.9%, and fentanyl 102.6%. The pH stayed between 4.76 and 4.79, the solutions remained clear, and the weight was 99.9% of that found initially. The solution was also stable for 7 days at room temperature. The concentrate was stable (> 90%) for 9 months at 2-8°C., Conclusion: The solution containing adrenaline, fentanyl, and bupivacaine, stabilised with disodium edetate, is stable for several months at 2-8°C, and at least for 7 days at room temperature without the addition of sulphites., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: A new disposable flexible videoscope, the Ambu® aScope, has several potential advantages compared with reusable devices, but it is a prerequisite for its widespread use that it functions sufficiently well in the management of patients in whom difficulty with airway management is anticipated and awake intubation is indicated., Methods: In a pilot study, 20 patients with normal airways were intubated with the aScope. Subsequently, 40 patients with predicted difficult tracheal intubation were randomly assigned to be intubated awake with either the aScope or the reusable Olympus BF videobronchoscope., Results: All patients were successfully intubated awake. The median total intubation time, including the administration of local anaesthesia, was 278 vs. 234 s in the aScope and Olympus groups, respectively (P = 0.03). In two cases in the aScope group, the image became blurred immediately after the first injection of lidocaine via the injection channel, and the time that it took to replace the scopes was included in the intubation times., Conclusion: Both the disposable aScope and the reusable Olympus videoscope allowed safe awake intubation in our elective patients with severely difficult, but uncompromised, airways. The occasional need to employ a spare scope because of malfunctioning would make the disposable aScope less suitable in patients with acutely compromised airways., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Articaine and chloroprocaine have recently gained interest as short-acting spinal anaesthetics. Based on previous work comparing articaine 60 mg with chloroprocaine 40 mg, we hypothesised that articaine 40 mg and chloroprocaine 40 mg would produce similar spinal anaesthesa regarding block onset, maximal spread, and recovery., Methods: In this randomised, double-blind study, adult patients (18-70 years, American Society of Anaesthesiologists physical status I-III, BMI < 36 kg/m(2) ) scheduled for day-case knee arthroscopy received either articaine 40 mg (20 mg/ml) (group A40, n = 16) or chloroprocaine 40 mg (20 mg/ml) (group C40, n = 18) intrathecally. Telephone interviews were performed on the first and seventh postoperative day to disclose possible side effects, e.g. transient neurological symptoms (TNS)., Results: The groups were comparable regarding demographic data, onset and maximal spread of spinal anaesthesia, and duration of surgery. Surgery could be performed successfully under spinal anaesthesia except once in A40 (insufficient block) and once in C40 (prolonged surgery). Complete recovery was significantly slower in A40 vs. C40 for both motor block (105 (94/120) vs. 75 (71/90) min) [P < 0.001, Mann-Whitney U-test (MW-U)] and sensory block [135 (109/176) vs. 105 min (90/124)] (P < 0.02, MW-U), respectively [data are median (25th/75th percentiles)]. One patient from A40 showed mild TNS., Conclusion: Both A40 and C40 provided mainly adequate spinal anaesthesia for day-case knee arthroscopy. While onset and maximal spread were comparable, the recovery from motor block was clearly faster with chloroprocaine after equivalent doses of spinal articaine and chloroprocaine., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Segmental dose reduction with increasing age after thoracic epidural anaesthesia (TEA) has been documented. We hypothesised that after a fixed loading dose of ropivacaine at the T3-T4 level, increasing age would result in more extended analgesic spread. In addition, other aspects of neural blockade and haemodynamic changes were studied., Methods: Thirty-five lung surgery patients were included in three age groups. Thirty-one patients received an epidural catheter at the T3-T4 interspace followed by an injection of 8-ml ropivacaine 0.75%. Analgesia was assessed with pinprick and temperature discrimination. Motor block was tested using the Bromage and epidural scoring scale for arm movements score. An arterial line was inserted for invasive measurement of blood pressure, cardiac index (CI) and stroke volume (SV)., Results: There was no influence of age on quality of TEA except for the caudal border of analgesia being somewhat lower in the middle and older age group compared with the young age group. Heart rate (6.0 ± 5.9, P < 0.001), mean arterial pressure (16.1 ± 15.6, P < 0.001), CI (0.55 ± 0.49, P < 0.001) and SV (9.6 ± 14.6, P = 0.001) decreased after TEA for the total group. Maximal reduction in heart rate after TEA was more extensive in the young age group compared with the other age groups. There was no effect of age on other cardiovascular parameters., Conclusion: We were unable to demonstrate an effect of age on the maximal number of spinal segments blocked after TEA; however, the caudad spread of analgesia increased with advancing age. In addition, reduction of heart rate was greater in the youngest group., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Involutional changes of peripheral nervous system occur with aging. The aim of the study was to determine the minimum effective volume of local anesthetic required to offer an effective ultrasound-guided supraclavicular brachial plexus block in 50% of middle-aged (< 50 years) and elderly (> 65 years) patients. We hypothesized reduced minimum effective volume of local anesthetic in elderly patients., Methods: Middle-aged (n = 22) and elderly (n = 22) patients undergoing upper limb surgery received an ultrasound-guided supraclavicular brachial plexus block. Structural analysis of the brachial plexus in supraclavicular region was obtained by measuring the cross-sectional area. The prospective, observer-blinded study method is a previously validated step-up/step-down sequence model where the local anesthetic volume for the next patient is determined by the outcome of the previous block. The starting volume was 30 ml (50 : 50 mixture, 0.5%wt/vol levobupivacaine, 2%wt/vol lidocaine). The minimum effective volume of local anesthetic was determined using Dixon and Masey method., Results: The minimum effective local anesthetic volume significantly differed between middle-aged and elderly [23.0 ml, 95% confidence interval (CI) 13.7-32.3 vs. 11.9 ml, 95% CI 9.3-14.6; 95% CI of the difference 1.6-20.6, P = 0.027]. The cross-sectional area of brachial plexus was 0.95 ± 0.15 in middle-aged and 0.51 ± 0.06 cm(2) in elderly patients (P < 0.001)., Conclusions: Within the present study, we report a reduced minimum effective anesthetic volume for ultrasound-guided supraclavicular block in elderly patients. Additionally, smaller cross-sectional surface area of brachial plexus in the supraclavicular region was observed., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Background: Bladder catheterisation may be inconvenient for patients, delay mobilisation and risk complications. We hypothesised that by excluding pre-operatively patients at high risk of post-operative urinary retention, the majority of patients could avoid perioperative catheterisation during low-dose spinal anaesthesia., Methods: Patients undergoing total knee arthroplasty were assigned if fit for spinal anaesthesia and without severe symptoms of lower urinary tract obstruction, gross incontinence, mobilisation difficulties hindering micturition and > 200 ml residual urine volume. Bladder volume was monitored by ultrasound and temporary catheterisation advised if > 400 ml., Results: Fifty-two patients (men 54%, age 65 ± 9 years, body mass index 31 ± 5, 30% with history of urinary tract problems) were included. Intrathecal hyperbaric bupivacaine given was 7.8 ± 1.08 mg and always 7.5 μg sufentanil providing sufficient anaesthesia in all cases. Crystalloid given during surgery was 8.5 ± 4.0 ml/kg. Voluntary micturition was reached by 46 patients (88%, confidence interval (CI) 79-97%), but six (12%, CI 3-21%) needed temporary catheterisation once (four men/two women). Larger bladder volumes were found in those catheterised than those with voluntary micturition on the pre-operative (131 ± 76 ml vs. 68 ± 57 ml, P = 0.03) and first post-operative bladder scan (445 ± 169 ml vs. 271 ± 129 ml, P = 0.004). All but two patients (96%) could be mobilised the same day. No patient suffered bladder dysfunction., Conclusion: Low-dose spinal anaesthesia combined with simple selection criteria allowed for early mobilisation (96%) and avoidance of bladder catheterisation in the vast majority (88%) of patients undergoing total knee arthroplasty, and the rest (12%) only needed a single temporary catheterisation., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation.)

Background: Ultrasound guidance has been shown to reduce the minimum effective volume (MEV) of local anaesthetics for several peripheral nerve blocks. Although the lateral sagittal infraclavicular block (LSIB) is a well-established anaesthesia method, MEV for this technique has not been established. Our aim with this study was to determine the MEV using ropivacaine 7.5 mg/ml for the LSIB method., Methods: Twenty-five adult American Society of Anesthesiologists physical status I-II patients scheduled for hand surgery received an ultrasound-guided LSIB with ropivacaine 7.5 mg/ml. A successful block was defined as anaesthesia or analgesia for all five sensory nerves distal to the elbow, 30 min after local anaesthetic injection. The MEV for a successful block in 50% of the patients was determined by using the staircase up-and-down method introduced by Dixon and Massey. Logistic regression and probit transformation were applied to estimate the MEV for a successful block in 95% of the patients., Results: The patients received ropivacaine 7.5 mg/ml volumes in the range of 12.5-30 ml. The MEVs in 50% and 95% of the patients were 19 ml [95% confidence interval (CI), 14-27] and 31 ml (95% CI, 18-45), respectively., Conclusions: For surgery distal to the elbow, the MEV in 95% of patients for an ultrasound-guided LSIB with ropivacaine 7.5 mg/ml was estimated to be 31 ml (95% CI, 18-45 ml). Further studies should determine the factors that influence the volume of local anaesthetic required for a successful infraclavicular block., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation.)

Background: Open radical retropubic prostatectomy (ORRP) is associated with moderate pain. We hypothesized that a transversus abdominis plane (TAP) block would reduce post-operative pain, morphine consumption and opioid-related side effects compared with wound infiltration and placebo in this population., Methods: This was a randomized, double-blind and placebo-controlled study. The operations were performed with patients in general anaesthesia. Patients were allocated to receive either bilateral TAP block (n = 23), wound infiltration (n = 25) or placebo (n = 25). Treatment was 40 ml ropivacaine 0.75% and placebo was 40 ml saline 0.9%. Pre-operatively, all patients received oral gabapentin, ibuprofen and paracetamol, followed by oral paracetamol and ibuprofen at regular doses and intervals, and patient-controlled analgesia with IV morphine from 0 h to 24 h post-operatively., Results: Visual analogue scale pain score during mobilization 4 h post-operatively (primary outcome) did not differ significantly between the TAP block and placebo group (TAP 28 ± 22 mm vs. placebo 33 ± 18 mm, P = 0.64). Pain scores (as area under the curve) during the first 24 h were not significantly different among any of the three groups, neither at rest nor during mobilization. Morphine consumption (0-24 h) did not differ significantly between groups {TAP block = 15 [8-23] mg, infiltration 15 [8-36] mg, placebo 15 [3-30] mg, [median (interquartile range)]}. Levels of nausea, sedation and number of vomits were not different among the groups., Conclusion: Neither TAP block nor wound infiltration with ropivacaine improved a basic multimodal analgesic regimen with paracetamol, ibuprofen and gabapentin after ORRP., (© 2013 The Acta Anaesthesiologica Scandinavica Foundation.)

Background: Hyperbaric prilocaine 20 mg/ml may be preferable for perianal outpatient surgery. The aim of this prospective, single-centre, randomised, single-blinded, controlled clinical trial was to determine the optimal dosage of hyperbaric prilocaine 20 mg/ml for a spinal anaesthesia (SPA) in patients undergoing perianal outpatient surgery., Methods: One hundred and twenty patients (18-80 years/American Society of Anesthesiologists grade I-III) were enrolled in this study. The patients were randomised to receive 10, 20 or 30 mg of prilocaine for SPA. We measured expansion of the sensory and motor block, evaluated times to walk, void and being eligible for discharge, and determined the demand of analgesics., Results: 116/120 patients were available for analysis. The expansion of the sensory block gained with an increasing dosage: 10 mg: 3(1-6) dermatomes; 20 mg: 4(2-6) dermatomes; 30 mg: 5(3-7) dermatomes (P < 0.0001). Dermatomes were counted upwards beginning with S(5). Also, the motor block gained with an increased dosage (Bromage score 1-3: 10 mg: n = 3, 20 mg: n = 8 and 30 mg: n = 18, P = 0.0002). Patients receiving 10 mg were ready for discharge earlier compared with both other groups (10 mg: 199 ± 39 min; 20 mg: 219 ± 47 min; 30 mg: 229 ± 32 min, P = 0.0039). Pain occurred earlier in the 10 mg group than in the 30 mg group (10 mg: 168 ± 36 min; 30 mg: 205 ± 33 min, P = 0.0427). The demand of additional analgesics was comparable in all dosage groups., Conclusion: Hyperbaric prilocaine 20 mg/ml can be applied in dosages of 10, 20 and 30 mg for SPA in perianal surgery. Because of sufficient analgesia, missing motor block and shorter recovery times, 10 mg of hyperbaric prilocaine 20 mg/ml can be recommended for perianal outpatient surgery., (© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)

Background: Predictors of laterality of motor block during epidural analgesia are currently unknown, as studies so far have yielded conflicting results. We aimed to evaluate predictors of post-operative asymmetric lower extremity motor blockade in a mixed surgical population., Methods: This is a retrospective analysis of 578 consecutive patients with post-operative epidural analgesia for a variety of surgical procedures. A priori determined potential predictors of unilateral motor block were age, gender, body mass index, type of surgical procedure, vertebral level of puncture, catheter insertion depth into the epidural space and concentration of local anaesthetic. Logistic regression analysis was employed for evaluating predictors of laterality., Results: Unilateral motor block occurred in 29.2% of the patients. Univariate logistic regression analysis showed that young age, female gender, gynaecologic procedures, a low puncture level, an increased depth of catheter insertion and a high ropivacaine concentration (2 mg/ml vs. less than 2 mg/ml) were significantly associated with increased incidence of laterality. Multivariate analysis revealed that age (OR = 0.73 per decade increase, P = 0.00001), the vertebral level of epidural puncture (OR = 1.37 per lowering vertebral level, P < 0.000001) and the depth of catheter insertion (OR = 1.46 per centimetre deeper, P = 0.001) were independent predictors of unilateral motor block., Conclusion: These results suggest that young patients with lumbar epidural analgesia or deep catheter insertion should be frequently monitored for the occurrence of laterality of motor block. Also, these results provide support for a prospective study to determine the optimal catheter insertion depth to decrease the risk of unilateral motor block., (© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)

Background: The rapid and short-acting local anaesthetic articaine is a feasible spinal anaesthetic for day-case open inguinal herniorrhaphy (OIH). We hypothesised that similarly to other spinal local anaesthetics, the addition of fentanyl may prolong articaine spinal analgesia without prolonging motor block., Methods: We performed a randomised, controlled study in 100 adult patients undergoing OIH. Spinal anaesthesia was induced by injecting hyperbaric articaine 72 mg with (Group A + F) or without (Group A) fentanyl 10 μg with the patient in lateral decubitus position. The distribution of sensory block was tested using pinprick and controlled by tilting the operating table 10 up or down. Motor block testing was based on the patient's ability to flex knees and ankles. Rescue analgesic was intravenous (i.v.) fentanyl. Pain scores were registered, and i.v. paracetamol 1 g was given as the first post-operative analgesic., Results: There were no differences (A + F vs. A) in the maximum median extension of the sensory block (T5 vs. T5), mean duration of sensory block ≥ T10 (76 min vs. 73 min), or total duration of sensory (146 min vs. 146 min) or motor block (99 min vs. 107 min). Fewer patients in Group A + F needed fentanyl (5 vs. 14, P < 0.05) perioperatively or paracetamol (3 vs. 18, P < 0.001) post-operatively., Conclusion: Fentanyl 10 μg added to spinal hyperbaric articaine improved analgesia and reduced analgesic consumption during and after OIH. Fentanyl did not prolong motor block or delay recovery., (© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)

Background: Post-operative sore throat (POST) has increasingly been a common clinical complication particularly in thyroid surgery. We conducted a trial to evaluate the effect of non-pharmacological [smaller-sized endotracheal tube (ETT)] combined with pharmacological intervention [lidocaine intravenous (i.v.)] on POST in women undergoing thyroid surgery., Methods: Two hundred and forty patients scheduled for thyroid surgery were randomly divided into four groups: Group A, ETT size 7.0 with saline; Group B, ETT size 6.0 with saline; Group C, ETT size 7.0 with lidocaine; Group D, ETT size 6.0 with lidocaine. Patients in Groups C and D received i.v. 1.5 mg/kg lidocaine that was filled in syringe up to 10 ml 5 min before induction of anaesthesia; whereas patients in Groups A and B received an equal volume of saline. The incidence and severity of POST were evaluated at 1, 6 and 24 h after tracheal extubation., Results: The highest incidence of POST occurred at 6 h after extubation in all groups. The incidence of POST was significantly lower in Group D compared with Groups A (23% vs. 62%, P < 0.01), B (23% vs. 42%, P = 0.03) and C (23% vs. 43%, P = 0.02) at 6 h after extubation. Group D had significantly decreased severity of POST compared with Groups A, B and C 6 and 24 h after extubation (P < 0.05)., Conclusion: Use of smaller-sized ETT combined with i.v. lidocaine decreases the incidence and severity of POST in women undergoing thyroid surgery., (© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)

The specific blocking of the axillary nerve has never been investigated clinically. We present four cases illustrating potential applications of the axillary nerve block in the perioperative setting and discuss possible directions for future research in this area. The axillary nerve blocks were all performed using a newly developed in-plane ultrasound-guided technique. In one patient undergoing arthroscopic shoulder surgery, we used the axillary nerve block as the only analgesic combined with propofol sedation and spontaneous breathing. Chronic shoulder pain was eliminated after the axillary nerve block in two patients. The pain score after arthroscopic shoulder surgery in these two patients remained low until termination of the nerve block. In a fourth patient, severe post-operative pain after osteosynthesis of a displaced proximal humerus fracture was almost eliminated after performing an axillary nerve block. These findings warrant larger clinical trials that investigate the pain-mediating role of the axillary nerve in the perioperative setting., (© 2012 The Authors. Acta Anaesthesiologica Scandinavica © 2012 The Acta Anaesthesiologica Scandinavica Foundation.)