A randomised controlled comparison between stimulating and standard catheters for lumbar plexus block.

The aim of this randomised, prospective, blinded study was to evaluate if stimulating catheters can decrease the minimum effective anaesthetic volume in 50% of patients during lumbar plexus block using mepivacaine 1.5% compared with standard catheters. Fifty-eight patients of ASA physical status 1-3 were randomly allocated to receive a lumbar plexus block via a stimulating or standard catheter, with 29 in each group. The first dose was 30 ml and subsequent doses were determined using the up-and-down staircase method. The minimum effective anaesthetic volume50 was 12.2 ml (95% CI 7.3-17.1 ml) using the stimulating catheter and 24.8 ml (95% CI 23.2-27.5 ml) with the standard catheter (p < 0.0001). Complete lumbar plexus block was achieved with the initial dose of mepivacaine in 29 (100%) patients in the stimulating catheter group and 20 (69%) patients in the standard catheter group (p = 0.002). This study showed that use of a stimulating catheter halves the minimum effective anaesthetic volume50 of mepivacaine 1.5% while increasing the success rate in patients receiving continuous lumbar plexus block.

Intrathecal 1% 2-chloroprocaine vs. 0.5% bupivacaine in ambulatory surgery: a prospective, observer-blinded, randomised, controlled trial.

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.

Pilot double-blinded study to assess efficacy and tolerability of morphine sulphate oral solution (Oramorph®) given preoperatively as add-on therapy within a multimodal postoperative pain approach in patients undergoing laparoscopic cholecystectomy.

BACKGROUND: This study aims at investigating the effect of a single pre-operative oral administration of morphine sulphate (Oramorph®) on pain after laparoscopic cholecystectomy (LC). METHODS: Forty-one ASA I-III patients, aged 18-65 years, undergoing LC were randomly, double-blindly allocated to treatment (N.=20, 30mg Oramorph®, group M) or placebo (N.=21, group P). General anesthesia was maintained with propofol and remifentanil. All patients received ketamine 0.2 mg/kg iv at induction, intraoperative ketorolac 30mg iv and tramadol postoperatively (iv PCA: bolus 50 mg, lock-out 30 min, max 100 mg/4 hours). Numerical rating scale for pain (NRS), White's fast track and PADSS scores, tramadol consumption and adverse events were recorded for the first 24h. All patients underwent State Trait Anxiety Inventory (STAI) and Mini Mental State Examination (MMSE). RESULTS: Anthropometric characteristics, MMSE, STAI, ASA status, NRS rest, White's and PADDS scores, PONV incidence were similar. Group M showed significantly lower NRS on movement during the first 3 hours after awakening. Cumulative tramadol consumption was lower in group M than in group P (185±142 mg versus 263±199 mg, P=0.199). CONCLUSION: Within a multimodal approach, a single preoperative oral administration of 30 mg of morphine sulphate in patients undergoing LC did not improve pain at rest, but improved NRS on movement during the first 3 hours after awakening. Group P required a higher mean dose of tramadol compared to Group M, although not significantly. The safety profile of Oramorph® allowed fast extubation and awakening times as well as prompt home discharge within 6 hours from surgery.

Difficult mask ventilation in obese patients: analysis of predictive factors.

BACKGROUND: This study aimed to determine the accuracy of commonly used preoperative difficult airway indices as predictors of difficult mask ventilation (DMV) in obese patients (BMI >30 kg/m2). METHODS: In 309 consecutive obese patients undergoing general surgery, the modified Mallampati test, patient's Height/Thyromental distance ratio, Inter-Incisor Distance, Protruding Mandible (PM), history of Obstructive Sleep Apnea and Neck Circumference (NC) were recorded preoperatively. DMV was defined as Grade 3 mask ventilation (MV) by the Han's scale (MV inadequate, unstable or requiring two practitioners). Data are shown as means±SD or number and proportions. Independent DMV predictors were identified by multivariate analysis. The discriminating capacity of the model (ROC curve area) and adjusted weights for the risk factors (odds ratios) were also determined. RESULTS: BMI averaged 42.5±8.3 kg/m2. DMV was reported in 27 out of 309 patients (8.8%; 95%CI 5.6-11.9%). The multivariate analysis retained NC (OR 1.17; P<0.0001), limited PM (1.99; P=0.046) and Mallampati test (OR 2.12; P=0.009) as risk predictors for DMV. Male gender was also included in the final model (OR 1.87; P=0.06) as biologically important variable albeit the borderline statistical significance. The model yielded a good discriminating capacity (ROC curve 0.85). The four parameters were used to create an unweighted prediction score (ROC curve 0.84) with >2 associated factors as the best discriminating point for DMV. CONCLUSION: Obese patients show increased incidence of DMV with respect to the undifferentiated surgical population. Limited PM, Mallampati test and NC are important DMV predictors.

Prospective randomized comparison of ultrasound-guided and neurostimulation techniques for continuous interscalene brachial plexus block in patients undergoing coracoacromial ligament repair.

BACKGROUND: There are few data comparing the onset time of interscalene brachial plexus block performed using ultrasound (US) guidance or nerve stimulation (NS) technique for elective coracoacromial ligament repair. METHODS: Fifty ASA I-III patients were randomly allocated to receive a continuous interscalene brachial plexus block with 20 ml of 1% ropivacaine with either NS or US guidance. The time of block performance, number of skin punctures and needle redirections, inadvertent vascular punctures, and procedure-related pain scores were recorded. The onsets of sensory and motor blocks in the distribution of radial, axillary, and musculocutaneous nerves were blindly assessed every 5 min until 30 min from the end of local anaesthetic (LA) injection. Intraoperative fentanyl, general anaesthesia (GA) requirements, postoperative pain scores, LA consumption, and patients' requirements for subcutaneous morphine during the first 24 h were compared. RESULTS: Block onset times were similar. The time to complete the block and the number of skin punctures and vascular punctures were significantly lower in Group US. There were no differences in needle redirections, incidence of paraesthesiae, intraoperative fentanyl consumption, and requirements for GA or postoperative morphine. The US group required significantly less LA only at 16 h after surgery and had lower pain scores at rest at 24 h after surgery. CONCLUSIONS: Block onset times and success rate were similar whether NS or US was used, although US guidance allowed shorter procedural times, fewer needle punctures, and fewer vascular punctures.

Tramadol and 0.5% levobupivacaine for single-shot interscalene block: effects on postoperative analgesia in patients undergoing shoulder arthroplasty.

BACKGROUND: The aim of this study was to evaluate the efficacy of tramadol as an adjuvant to the local anaesthetic solution in patients undergoing shoulder arthroscopy for rotator cuff tear after middle interscalene block (MIB). METHODS: We enrolled 120 patients (ASA I-II), scheduled for arthroscopic surgery for rotator cuff tear. The patients were sedated with midazolam 0.02 mg/kg and haloperidol 2 mg i.v. before performing MIB. All subjects underwent a MIB with 0.4 mL/kg of 0.5% levobupivacaine. After computerized randomization, all patients were allocated in 1 of 3 groups, each including 40 subjects. Group Placebo (Group P) received 0.4 mL/kg of 0.5% levobupivacaine plus isotonic sodium chloride for MIB and isotonic sodium chloride i.m. Group "Perineural Tramadol" (Group TPN) received 0.4 ml/Kg of 0.5% levobupivacaine plus 1.5 mg/kg of tramadol perineurally and isotonic sodium chloride i.m. Group "Intramuscular Tramadol" (Group TIM) received 0.4 ml/Kg of 0.5% levobupivacaine plus isotonic sodium chloride perineurally and 1.5 mg/kg of tramadol i.m. RESULTS: The MIB onset times were not statistically different in the three groups. The duration of analgesia was significantly longer in Groups TPN and TIM, where tramadol was administered, either i.m. or perineurally, compared with the placebo group. A significant statistical difference was found in the duration of analgesia between the group TPN and TIM. CONCLUSION: The addition of tramadol to the local anaesthetic solution administered for MIB provided a longer duration of analgesia compared with placebo and i.m tramadol administration in patients undergoing arthroscopic surgery for rotator cuff tear.

The nerve stimulation technique versus the loss of resistance technique for the posterior approach to lumbar plexus block: a randomized, prospective, observer-blinded, pilot study.

BACKGROUND: This prospective, randomized, observer-blinded, pilot study compares the effects of the nerve stimulation guidance technique (NS) with the loss of resistance technique (LOR) on readiness for surgery during the posterior approach to lumbar plexus block. METHODS: Thirty ASA status I-III patients who were 18-85 years old and who were undergoing hip fracture repair were enrolled. After parasacral sciatic nerve block, patients were randomly allocated to receive a continuous posterior lumbar plexus block using nerve stimulation (n=15) or a continuous psoas compartment block using the loss of resistance technique (n=15) with 20 ml of 1.5% mepivacaine. A blinded observer monitored for sensory and motor block onsets every 5 minutes. We defined readiness for surgery as complete numbness to the pinprick test and complete motor block on the surgical side. If incomplete, the lumbar plexus block was supplemented with 10 mL of 1.5% mepivacaine through the catheter before surgery. Intraoperative fentanyl or general anesthesia requirements, pain scores, local anesthetic consumption, morphine requirements for breakthrough pain and side effects were monitored. RESULTS: The mean time to readiness for surgery was 12±6 min Group NS and 22±6 min in Group LOR (P=0.03). Three patients in Group NS and 9 patients in Group LOR required additional boluses of local anesthetic through the lumbar plexus catheter before surgery (P=0.113). CONCLUSION: Nerve stimulation allowed faster readiness for surgery than loss of resistance. Nevertheless, the two techniques seem to be comparable in terms of local anesthetic consumption, morphine requirements and pain scores.

Continuous peripheral nerve blocks in acute pain management.

The indications for continuous nerve blocks for the perioperative pain management in hospitalized and ambulatory patients have extended well beyond orthopaedics. These techniques are not only used to control pain in patients undergoing major upper and lower extremity surgery, but also to provide perioperative analgesia in patients undergoing abdominal, plastic, urological, gynaecological, thoracic, and trauma surgeries. Infusion regimens of local anaesthetics and supplements must take into consideration the condition of the patient before and after surgery, the nature and intensity of the surgical stress associated with the surgery, and the possible need for immediate functional recovery. Continuous nerve blocks have proved safe and effective in reducing opioid consumption and related side-effects, accelerating recovery, and in many patients reducing the length of hospital stay. Continuous nerve blocks provide a safer alternative to epidural analgesia in patients receiving thromboprophylaxis, especially with low molecular-weight heparin.

Posterior psoas vs 3-in-1 approach for lateral femoral cutaneous and obturator nerve block for anterior cruciate ligament repair.

AIM: The aim of this article was to test the hypothesis that the posterior psoas compartment approach to the lumbar plexus help to achieve better blockade of the lateral femoral cutaneous and obturator nerves than the classic anterior 3-in-1 femoral nerve block. METHODS: Thirty-six patients who were undergoing anterior cruciate ligament repair were randomly allocated to receive a femoral nerve block using either an anterior 3-in-1 femoral block (group Femoral, N=18) or a posterior psoas compartment approach (group Psoas, N=18) using 30 mL of 1.5% mepivacaine. Successful nerve block was defined as a complete loss of pinprick sensation in the region that is supplied by the lateral femoral cutaneous nerve along with adequate motor block of the obturator nerve 30 minutes after injection. The degree of motor block of the obturator nerve was measured using adduction strength with a mercury sphygmomanometer as previously described by Lang. RESULTS: Thirty minutes after the completion of the block, sensory block of the lateral femoral cutaneous nerve was observed in 14 patients (78%) from the Psoas group and in 3 patients (17%) from the Femoral group (P=0.001). Thirty minutes after the completion of the block, a 119+/-40 mmHg decrease was found in Psoas group, in contrast to the 25+/-22 mmHg decrease found in the Femoral group (P<0.0005). CONCLUSIONS: The posterior psoas compartment approach provides a more reliable block of the lateral femoral cutaneous and obturator nerves than the anterior 3-in-1 approach.

Ultrasound vs nerve stimulation multiple injection technique for posterior popliteal sciatic nerve block.

In this prospective, randomised, observer-blinded study we evaluated whether ultrasound guidance can shorten the onset time of popliteal sciatic nerve block as compared to nerve stimulation with a multiple injection technique. Forty-four ASA I-III patients undergoing posterior popliteal sciatic nerve block with 20 ml of 0.75% ropivacaine were randomly allocated to nerve stimulation or ultrasound guided nerve block. A blinded observer recorded onset of sensory and motor blocks, success rates, the need for fentanyl intra-operatively, the requirement for general anaesthesia, procedure-related pain, patient satisfaction and side-effects. Onset times for sensory and motor blocks were comparable. The success rate was 100% for ultrasound guided vs 82% for nerve stimulation (p = 0.116). Ultrasound guidance reduced needle redirections (p = 0.01), were associated with less procedural pain (p = 0.002) and required less time to perform (p = 0.002). Ultrasound guidance reduced the time needed for block performance and procedural pain.

Continuous lumbar epidural infusion of levobupivacaine: effects of small-or large-volume regimen of infusion.

BACKGROUND: The question of whether the dose, concentration or volume of a local anesthetic solution is the relevant determinant of the spread and quality of post-operative epidural analgesia is still open. In this prospective, randomized, double-blind study, we compared the effects of a large volume-low concentration with a small-volume-high-concentration lumbar epidural infusion of levobupivacaine. METHODS: Seventy patients scheduled for total hip replacement were enrolled. After surgery, patients were randomly allocated to receive a continuous epidural infusion of levobupivacaine (10.5 mg/h) using either 0.125% levobupivacaine infused at 8.4 ml/h (low concentration group, n=35) or 0.75% levobupivacaine infused at 1.4 ml/h (high concentration group, n=35). We blindly recorded the degree of pain relief at rest and during movement every 8 h for the first two post-operative days, as well as hip flexion, motor block, rescue analgesic consumption and adverse events. RESULTS: No difference in pain relief was observed between groups as estimated with the areas under the curve of the verbal Numerical Rating Scale for pain over time, both at rest and during movement. Similarly, there was no difference between groups in hip flexion degree, motor blockade and hemodynamic stability. CONCLUSIONS: Continuous lumbar epidural infusion of 0.75% levobupivacaine was as effective as continuous lumbar epidural infusion of 0.125% levobupivacaine, when administered at the same hourly dose of 10.5 mg, in achieving adequate analgesia both at rest and during movement, without differences in the incidence of hypotension and motor blockade.

Ipsilateral shoulder pain after thoracotomy surgery: a prospective, randomized, double-blind, placebo-controlled evaluation of the efficacy of infiltrating the phrenic nerve with 0.2%wt/vol ropivacaine.

BACKGROUND: The aim of this prospective, randomized, double-blind, placebo-controlled study was to evaluate the efficacy of phrenic nerve infiltration with ropivacaine 0.2% on the incidence and severity of ipsilateral shoulder pain after thoracotomy in patients receiving continuous thoracic epidural analgesia. METHODS: Fifty ASA physical status II-III patients, receiving thoracic epidural analgesia for post-thoracotomy pain, were randomly allocated to receive infiltration of the ipsilateral phrenic nerve with either ropivacaine 0.2% 10 mL (ropivacaine, n = 25), or saline 0.9% (control, n = 25) just before lung expansion and chest closure. A blinded observer recorded the incidence and severity of ipsilateral shoulder pain 6, 12, 24, 36 and 48 h after surgery. Postoperative respiratory function was also evaluated with blood gas analyses. RESULTS: The cumulative incidences of ipsilateral shoulder pain during the first 24 h after surgery were 8/25 in the ropivacaine and 16/25 in the control groups (P = 0.047), with median (range) onset times for shoulder pain of 2 (2-24) h with ropivacaine and 0.5 (0.5-24) h in controls (P = 0.005). No differences were reported on the second postoperative day. The areas under the curves of the amount of pain over time were 0 (0-2760) mm h for the ropivacaine and 350 (0-1900) mm h for the control groups (P = 0.06). Postoperatively, similar reductions in indices of oxygenation were observed in both groups. CONCLUSIONS: Phrenic nerve infiltration with ropivacaine 0.2% 10 mL reduced the incidence and delayed the onset of ipsilateral shoulder pain during the first 24 h after open lung resection, with no clinically relevant effects on respiratory function.

Stimulating or conventional perineural catheters after hallux valgus repair: a double-blind, pharmaco-economic evaluation.

BACKGROUND: We prospectively evaluated direct analgesia-related costs of continuous sciatic nerve block using either a stimulating or conventional catheter after hallux valgus repair. METHODS: The perineural catheter was inserted through a stimulating introducer either blindly (group Conventional, n= 38) or while stimulating via the catheter (group Stimulating, n= 38). Nerve block was induced with 25 ml of mepivacaine 15 mg/ml, and was followed 3 h later by a patient-controlled infusion of ropivacaine 2 mg/ml (basal infusion: 3 ml/h; incremental dose: 5 ml; lock-out time: 30 min). Rescue tramadol [100 mg intravenous (i.v.)] was given if required. Local anesthetic consumption, need for rescue tramadol and post-operative nausea and vomiting (PONV) treatment, and patient's satisfaction were recorded during first 24-h infusion. Cost calculations were based on the acquisition cost of drugs and devices. RESULTS: Both techniques were similarly effective, but local anesthetic consumption and need for rescue analgesics were lower in the Stimulating group [respectively, 120 vs. 153 ml (P= 0.004) and 21% vs. 60% (P= 0.001)]. The analgesia-related costs for 24 h were similar when 100-ml bags of ropivacaine 2 mg/ml were used (66 euro vs. 67 euro; P= 0.26). When 200-ml bags of ropivacaine were used, the analgesia-related costs were higher in the Stimulating group than the Conventional group (75 euro vs. 55 euro; P= 0.0005). CONCLUSIONS: Direct costs of continuous sciatic nerve block ranged from 55 to 75 euro. Stimulating catheters reduced local anesthetic consumption and need for rescue analgesics. This was only cost effective when 100-ml bags of 2 mg/ml ropivacaine were used, while the cheapest combination was the use of conventional catheters and 200-ml bags of ropivacaine.

Locoregional anesthesia and coagulation.

The introduction of low molecolar weith heparin (LMWE) and the strong antithromboembolic prophylaxis protocols used in the USA, underlined the risk of spinal hemorrhage in patients receveing a neuraxial blockade. On the other side, the efficacy of these techniques over general anesthesia doesn't allow the anesthesist to miss this pratice, where possible. So it's necessary to quantify the spinal hematoma risk in patients assuming these drugs. Unfortunately, routine investigations on coagulation factors and platelets count are not reliable if patients are receiving LMWE. Waiting for dynamic tests concerning the coagulative status such as thromboelastography (TEG), many hospitals follow many different guidelines. For these reasons peripherical nerve block techniques are a good alternative, since they are not influenced by the efficacy of the coagulation system.

Monitored anesthesia care.

According to the American Society of Anesthe-siologists (ASA), a monitored anesthesia care (MAC) is a planned procedure during which the patient undergoes local anesthesia together with sedation and analgesia. Actually MAC is the first choice in 10-30% of all the surgical procedures. The 3 fundamental elements and purposes of a conscious sedation during a MAC are: a safe sedation, the control of the patient anxiety and the pain control. The patients undergoing conscious sedation are able to answer to orders appropriately and to protect airways. Last but not least, another purpose of any MAC is to get the patient appropriately satisfied, allowing him to get his discharge as faster as possible. There are many surgical procedures which can be performed using a MAC. The patient consciousness evaluation is of extreme importance during the surgical procedure performed with MAC: to this purpose the clinical and electroencephalographic evaluations such as Bispectral Index are very useful. MAC can be obtained with the association of fast half-life drugs or drugs getting a clinical effect which can vary according to the surgical requirements, using an infusion regiment. Apart from the pharmacological choice, this procedure can be performed with patient controlled sedation techniques or with continued intravenous infusion or with target controlled infusion.