The minimally effective concentration of adrenaline in a low-concentration thoracic epidural analgesic infusion of bupivacaine,fentanyl and adrenaline after major surgery. A randomized,double-blind,dose-finding study

BACKGROUND: We have documented that adrenaline 2.0 micro g.ml- 1 markedly improves relief of dynamic pain when added to a thoracic epidural analgesic infusion of bupivacaine 1 mg.ml- 1 and fentanyl 2 micro g.ml- 1. Concern about possible adverse effects on spinal cord blood flow, expressed by others, prompted us to find the lowest concentration of adrenaline needed to produce effective and reliable pain relief after major surgery. METHODS: A prospective, randomized, double-blind, parallel group study was carried out in 36 patients after major thoracic or upper abdominal surgery. Patients with only mild pain when coughing during titrated thoracic epidural infusion of approximately 9 ml per hour of bupivacaine 1 mg.ml- 1, fentanyl 2 micro g.ml- 1, and adrenaline 2.0 micro g.ml- 1 were included. The study was conducted as a dose-finding study comparing three different adrenaline concentrations in the epidural mixture (0.5, 1.0, and 1.5 micro g.ml- 1) with each other and with adrenaline 2.0 micro g.ml- 1 in our standard epidural mixture. On the 1st postoperative day, the patients were randomly allocated into three equal groups of 12 patients each, and given a double-blind epidural infusion at the same rate, but with different adrenaline concentrations (0.5, 1.0, or 1.5 micro g.ml- 1). The effects were observed for 4 h or until pain when coughing became unacceptable in spite of rescue analgesia. Rescue analgesia consisted of up to two patient-controlled epidural bolus injections per hour (4 ml) and subsequent i.v. morphine, if necessary. All patients received rectal paracetamol 1 g, every 6th hour. Main outcome measures were pain intensity at rest and when coughing, evaluated by a visual analogue scale and an overall quality of pain relief score. The extent of sensory blockade was evaluated by determining dermatomal hypaesthesia to cold. RESULTS: Pain intensity when coughing increased (P < 0.001) and the number of hypaesthetic dermatomal segments decreased (P < 0.002) when the concentration of adrenaline was reduced below 1.5 micro g.ml- 1 in the triple epidural mixture. This change started within two hours after reducing the concentration of adrenaline below 1.5 micro g.ml- 1. The differences in pain intensities at rest were less pronounced. After 4 h with adrenaline 0.5 or 1.0 micro g.ml- 1 pain intensity when coughing was unacceptable in spite of rescue analgesia. After restarting the standard epidural mixture with adrenaline 2.0 micro g.ml- 1, pain intensity was again reduced to mild pain when coughing and the sensory blockade was restored. Occurrence of pruritus increased with a decreasing adrenaline concentration. CONCLUSIONS: Adrenaline in a dose-related manner improves the pain-relieving effect and sensory blockade and decreases the occurrence of pruritus of a low-concentration thoracic epidural analgesic infusion of bupivacaine 1 mg. ml- 1 and fentanyl 2 micro g.ml- 1 after major thoracic or upper abdominal surgery. The minimally effective concentration of adrenaline, when added to bupivacaine 1 mg.ml- 1 and fentanyl 2 micro g.ml- 1, to maintain relief of dynamic pain is approximately 1.5 micro g.ml- 1. The data clearly document that dynamic, cough-provoked pain is a more sensitive outcome measure for postoperative pain relief than pain at rest.     

Analgesic duration and kinetics of liposomal bupivacaine after subcutaneous injection in mice

1. The objective of the present study was to assess the time-course profile of analgesia and bupivacaine concentrations at the site of injection after subcutaneous administration of a single dose of standard bupivacaine or a novel controlled-release liposomal bupivacaine formulation. 2. Groups of mice were injected subcutaneously with 0.2 mL of 0.5% standard bupivacaine or 0.5, 1 or 2% liposomal bupivacaine. 3. A prolonged duration of analgesia occurred in mice receiving liposomal bupivacaine. In the liposomal groups, the bupivacaine remained at the injection site for more than 96 h, compared with approximately 8 h in groups injected with standard bupivacaine. 4. These results confirm that the prolonged analgesia observed after injection of the liposomal formulation is associated with sustained higher levels of bupivacaine at the site of injection.     

Comparison of fentanyl-bupivacaine or midazolam-bupivacaine mixtures with plain bupivacaine for caudal anaesthesia in children

BACKGROUND: The aim of this study was to evaluate the intensity and effectiveness of 0.75 ml.kg-1 bupivacaine 0.25% with the addition of fentanyl or midazolam for caudal block in children undergoing inguinal herniorrhaphy. METHODS: Seventy-five children were allocated randomly to three groups to receive a caudal block with either 0.25% bupivacaine with fentanyl 1 microg.kg(-1) (group BF) or with midazolam 50 microg.kg(-1) (group BM) or bupivacaine alone (group B) after induction of anaesthesia. Haemodynamic parameters, degree of pain, additional analgesic requirements and side-effects were evaluated. RESULTS: The mean systolic arterial pressure at 10, 20, 30 min after caudal block was higher in group B compared with groups BF and BM. Mean intraoperative heart rate was lower in group BF than the other groups. Adequate analgesia was obtained in all patients (100%) in group BF, 23 patients (92%) in group BM and 21 patients (84%) in group B (P > 0.05). The time to recovery to an Aldrete score of 10 was significantly shorter in group B than group BM (P < 0.05). Although not significant, it was also shorter in group B than group BF. There was no difference in additional analgesic requirements between the groups in the first 24 h. Sedation score was higher in the midazolam group at 60 and 90 min postoperatively than the other groups. CONCLUSIONS: Caudal block with 0.75 ml.kg(-1) 0.25% bupivacaine and 50 microg.kg(-1) midazolam or 1 microg.kg(-1) fentanyl provides no further analgesic advantages to bupivacaine alone when administered immediately after induction of anaesthesia in children undergoing unilateral inguinal herniorrhaphy.     

A comparison of single dose caudal tramadol, tramadol plus bupivacaine and bupivacaine administration for postoperative analgesia in children

BACKGROUND: Our aim was to compare the effect of single dose caudal tramadol, tramadol plus bupivacaine and bupivacaine on the management of postoperative pain in children. METHODS: Sixty-three children in ASA groups I-II, between the ages of 1 and 5 were evaluated for postoperative pain randomly divided into three groups as follows: In group T, only tramadol was given caudally; in group TB, tramadol-bupivacaine was given caudally; in group B, bupivacaine was given alone. Pain was evaluated by using the paediatric objective pain scale (POPS). Sedation was evaluated with a 5-point test. There were no differences with age, weight, haemodynamic and respiratory parameters between groups. RESULTS: For 24 h postoperatively, the POPS value showed no statistically significant difference among groups (P > 0.05). Postoperative analgesia was maintained for 24 h. Nausea and vomiting was found to be higher in the tramadol group than in the bupivacaine group and tramadol-bupivacaine group (P < 0.001 and P < 0.01, respectively). CONCLUSION: Tramadol used caudally is as effective as bupivacaine in the management of postoperative pain in children and the addition of tramadol to bupivacaine, when both drugs were administered caudally, did not prolong the duration of action of bupivacaine and is a safe agent in children.     

Efficacy and uptake of ropivacaine and bupivacaine after single intra-articular injection in the knee joint

The efficacy of ropivacaine 100 mg (5 mg ml^–1),150 mg (7.5 mg ml^–1) and 200 mg (10 mg ml^–1)and bupivacaine 100 mg (5 mg ml^–1) givenby intra-articular injection into the knee after the end ofsurgery was studied in 72 ASA I–II patients scheduledfor elective knee arthroscopy under general anaesthesia in arandomized, double-blind study. Kapake (paracetamol 1 gand codeine 60 mg) was given as a supplementary analgesic.Pain scores were assessed 1–4 h after surgery and a verbalrating scale of overall pain severity was assessed on secondpostoperative day. Ropivacaine or bupivacaine concentrationswere determined in peripheral venous plasma up to 3 h afterinjection in eight patients in each group. Verbal rating painscores were lower with ropivacaine 150 mg compared withbupivacaine 100 mg (P<0.05). There was a tendency forlower analgesic consumption and pain scores with all doses ofropivacaine (not significant). The mean (SD) maximum total plasmaconcentrations of ropivacaine were 0.64 (0.25), 0.78 (0.43),and 1.29 (0.46) mg litre^–1 after 100, 150 and200 mg. The corresponding unbound concentrations were 0.018(0.009), 0.024 (0.020) and 0.047 (0.022) mg litre^–1.Both were proportional to the dose. The maximum total concentrationafter bupivacaine 100 mg was 0.57 (0.36) mg litre^–1.The time to reach maximum plasma concentration was similar forall doses and varied between 20 and 180 min. All concentrationswere well below the threshold for systemic toxicity. Br J Anaesth 2001; 87: 570–6     

琥珀胆碱诱发吸气延长效应及机制

用63只麻醉、制动、切断双侧迷走神经、人工呼吸的家兔,以偏神经放电作为呼吸观测指标,观察股动脉注射射琥珀胆碱（Sch）诱发的肌梭传入活动对呼吸的影响。结果发现23只吸气延长,表现为吸气时程（Ti）明显延长,呼气时程（Te）有缩短趋势,Ti／Te比值增加;肌注布比卡因破坏肌梭后,同剂量Sch则便吸气延长效应明显减弱。提示股动脉注射Sch诱发的肌梭传入活动对呼吸运动具有明显的吸气增强作用。     

Epidural bupivacaine, sufentanil or the combination for post-thoracotomy pain

Analgesia with epidural bupivacaine, sufentanil or the combination was studied in 50 patients who had undergone thoracotomy. During operation all patients received an initial dose of bupivacaine 0.5% with adrenaline 5 micrograms.ml-1 (5-10 ml) by thoracic epidural catheter. One hour later the patients were divided into three groups: the bupivacaine group (bupivacaine 0.125%), the sufentanil group (50 micrograms sufentanil in 60 ml normal saline) and the combination group (50 micrograms sufentanil in 60 ml bupivacaine 0.125%). Analgesia in the three groups was provided by a continuous epidural infusion (5-10 ml.h-1) for 3 days. The mean dose of bupivacaine was significantly higher (P less than 0.05) in the bupivacaine group (12.07 mg.h-1 (s.e.mean 0.97 mg.h-1)), compared with the combination group (9.82 mg.h-1 (s.e.mean 0.43 mg.h-1)). The mean dose of sufentanil in the sufentanil group was similar to the combination group (6.37 micrograms.h-1 (s.e.mean 0.23 micrograms.h-1) and 6.52 micrograms.h-1 (s.e.mean 0.28 micrograms.h-1), respectively. The pain scores on the inverse visual analogue scale of most patients in the bupivacaine group were unacceptably low. The sufentanil group had much better pain scores, but on exercise these patients experienced more pain than the combination group. The combination group had, overall, better pain scores. In the combination group, there were better respiratory results.     

A comparison of spinal and epidural anaesthesia for hip arthroplasty

Spinal and epidural anaesthesia were compared in 65 patients undergoing hip arthroplasty, with regard to the degree of sensory and motor blockade, cardiovascular effects, operating conditions, the dose of propofol required to produce satisfactory hypnosis, and complications. Epidural anaesthesia was successful in 30 patients using an initial dose of 15 ml of 0.5% bupivacaine, and spinal anaesthesia in 32 patients, using 4 ml 0.5% isobaric bupivacaine. The two techniques were similar with regard to the level of sensory blockade (T8), degree of hypotension and perioperative haemorrhage. Differences occurred in the degree of motor blockade (mean Bromage score of 1 in the spinal group vs 3.86 in the epidural group) (P less than 0.05), time to achieve maximal cephalad spread (13 min in the spinal group vs 21 min in the epidural group) (P less than 0.05) and the dose of propofol required to produce adequate hypnosis (1.95 mg.kg-1.hr-1 in the spinal group vs 2.89 mg.kg-1.hr-1 in the epidural group) (P less than 0.05). Only seven patients required urethral catheterization in this spinal group compared with 14 in the epidural group (P less than 0.05). Spinal anaesthesia also proved advantageous by providing better operating conditions for the surgeon, with a lower incidence of patient movement.     

Intrathecal hyperbaric bupivacaine 3 mg + fentanyl 10 microg for outpatient knee arthroscopy with tourniquet

BACKGROUND: Combination of local anesthetic and opioid enables the use of less spinal anesthetic and increases the success of anesthesia. Intrathecal opioid does not prolong motor recovery and thus should not delay discharge home. We hypothesized that 3 mg of hyperbaric bupivacaine with 10 microg of fentanyl permits fast-tracking or shorter stay in post anesthesia care unit (PACU), and earlier discharge home, compared with 4 mg of hyperbaric bupivacaine. METHODS: In this double-blind study, 100 outpatients undergoing knee arthroscopy received randomly either 4 mg of bupivacaine (B4) or 3 mg of bupivacaine + 10 microg fentanyl (B3F) intrathecally. The volume of 0.8 ml was injected at the L2/3 interspace over a 2-min period. A lateral decubitus position was maintained for 10 min. The sensory block was recorded by using thermal stimuli, and motor block was assessed according to a modified Bromage scale. Fast-tracking criteria were complete recovery of motor block, sensory block Th12 or lower and stable vital signs. RESULTS: One block (1%) failed. Motor recovery was faster in the B3F group: 60% of the patients recovered in 80 min or less compared with 28% in group B4 (P = 0.002). The PACU-time was shorter: 36 (10-103) vs. 55 (10-140) min, respectively (P = 0.005). Seventeen (B3F) vs. nine patients (B4) could bypass PACU (NS). Time to discharge home was similar in both groups. In the B3F group, 75% of the patients developed pruritus. CONCLUSION: Both solutions produced reliable spinal anesthesia for outpatient knee arthroscopy. The PACU-time was shorter in the bupivacaine-fentanyl group, but both groups reached home-readiness equally.     

盐酸纳美芬预防全麻诱导期舒芬太尼诱发呛咳的临床观察

摘 要 目的：观察盐酸纳美芬对全麻诱导时使用的舒芬太尼引起的呛咳的预防作用,并观察其对插管过程中患者血流动力学的影响。方法: 全麻患者80例随机分为对照组和观察组。观察组患者在诱导前5min静脉注射盐酸纳美芬0.25 μg·kg^-1,对照组静脉注射等容量的0.9%氯化钠注射液,观察两组患者静脉注射舒芬太尼1 min内发生呛咳的次数和程度;监测并记录两组患者麻醉诱导前（T0）、静注舒芬太尼1min时（T1）和插管即刻（T2）的血压、心率和血氧饱和度等血流动力学指标变化。结果: 对照组呛咳发生率37.5%,观察组发生率为0,两组呛咳发生率及程度比较差异均有统计学意义（P<0.05）。对照组患者T1时血流动力学各指标较T0时点变化显著（P<0.05）,且与观察组有明显差异（P<0.05）,T2时各指标基本恢复到T0时点的水平。观察组患者在不同时点血流动力学各指标无明显波动（P＞0.05）。结论:预先注射盐酸纳美芬能有效减少全身麻醉诱导时舒芬太尼所致呛咳的发生及其程度,并减少因呛咳反应导致的血流动力学波动,但不影响舒芬太尼对插管反应的抑制作用。