The Effect of Propranolol and Phentolamine on Serum Gastrin Concentration in Response to Respiratory Acidosis in Normal Man

Abstract. Serum gastrin concentration and basal acid secretion were studied in normal subjects under the influence of respiratory acidosis induced by CO2 rebreathing. During the intragastric instillation of 100 ml/h 0. 5 M bicarbonate a significant increase of gastrinaemia from 130 to 158 pg/ml (p < 0. 01) occurred in ten subjects during respiratory acidosis (pCO₂ 62 torr, pH 7. 25). Under, the intragastric instillation of 100 ml/h 0. 1 N HC1 the rise of gastrin concentration in response to CO2 rebreathing (pC02 68 torr, pH 7. 20) was not significant. The relationship between the decrease of pH and the increase of the gastrin concentration was shifted in the direction of a greater systemic acidosis compared to the results performed in the presence of a neutral intragastric pH. 50 μg/kg propranolol intravenously produced a decrease of gastrin concentrations from 145 to 127 pg/ml (p < 0. 01) and a total suppression of hyper-gastrinaemia in respons'e to CO₂ rebreathing, suggesting activation of beta-cell receptors in respiratory acidosis. The infusion of phentolamine in a dose of 0. 6 to 1. 8 mg/min. resulted in a rise of gastrin concentration from 140 to 165 pg/ml (p < 0. 01) which was not further elevated during respiratory acidosis. The basal acid secretion showed a significant rise in response to CO2 rebreathing, which was abolished by the administration of propranolol.     

Comparison of ropivacaine with bupivacaine and lidocaine for ilioinguinal block after ambulatory inguinal hernia repair in children

BACKGROUND: We have compared ropivacaine with bupivacaine and lidocaine for ilioinguinal block in thirty children undergoing ambulatory inguinal hernia repair. METHODS: Patients were assigned randomly to receive 0.5 ml.kg(-1) of 0.2% ropivacaine (Group R, n = 10), 0.25% bupivacaine (Group B, n = 10) or 1% lidocaine (Group L, n = 10). The patients' parents, who were not informed of the type of local anaesthetic employed, evaluated the postoperative pain at 2 h and 6 h after operation using the Wong-Baker FACES Pain Rating Scale. RESULTS: There was a significant difference in the face scale score between Group R and Group L, and Group B and Group L. There was no difference in the face scale score between Group R and Group B. There were no complications or clinical evidence of local anaesthetic toxicity. CONCLUSIONS: We have confirmed that bupivacaine and ropivacaine are more effective than lidocaine in the prevention of postoperative pain after children's inguinal hernia repair. We suggest that ropivacaine 0.2% is an alternative to bupivacaine 0.25% for ilioinguinal block in ambulatory paediatric surgery.     

Density of spinal anaesthetic solutions of bupivacaine, levobupivacaine, and ropivacaine with and without dextrose

Background. Spread of intrathecal local anaesthetics is determinedprincipally by baricity and position of the patient. Hypobaricsolutions of bupivacaine are characterized by an unpredictablespread of sensory block whereas addition of dextrose 80 mg ml^–1provides a predictable spread but to high thoracic levels. Incontrast, dextrose concentrations between 8 and 30 mg ml^–1have shown reliable and consistent spread for surgery. Hence,the aim of this study was to determine the density of bupivacaine,levobupivacaine, and ropivacaine with and without dextrose atboth 23 and 37°C before embarking on clinical studies. Methods. Density (mg ml^–1) was measured using the methodof mechanical oscillation resonance, accurate to five decimalplaces on 1250 samples. 500 density measurements were performedin a randomized, blind fashion at 23 and 37°C on 10 plainsolutions of bupivacaine (2.5, 5, and 7.5 mg ml^–1) levobupivacaine(2.5, 5, and 7.5 mg ml^–1) and ropivacaine (2, 5, 7.5,and 10 mg ml^–1). Following this, 750 density measurementswere taken at 23 and 37°C on the 5 mg ml^–1 solutionsof bupivacaine, levobupivacaine, and ropivacaine with addeddextrose (10, 20, 30, 50, and 80 mg ml^–1). Results. There was a linear relationship between density anddextrose concentration for all three local anaesthetics (R²=0.99)at 23 and 37°C. The mean density of levobupivacaine 5 mgml^–1 was significantly greater than the densities of bupivacaine5 mg ml^–1 and ropivacaine 5 mg ml^–1 after adjustingfor dextrose concentration using analysis of covariance. Thisdifference existed both at 23 and 37°C. The mean (SD) densityof levobupivacaine 7.5 mg ml^–1 was 1.00056 (0.00003) mgml^–1, the lower 0.5% percentile (1.00047 mg ml^–1)lying above the upper limit of hypobaricity for all patientgroups. Conclusions. The density of local anaesthetics decreases withincreasing temperature and increases in a linear fashion withthe addition of dextrose. Levobupivacaine 5 mg ml^–1 hasa significantly higher density compared with bupivacaine 5 mgml^–1 and ropivacaine 5 mg ml^–1 at 23 and 37°Cboth with and without dextrose. Levobupivacaine 7.5 mg ml^–1is an isobaric solution within all patient groups at 37°C. Br J Anaesth 2004; 92: 547–51     

Lidocaine versus ropivacaine for continuous interscalene brachial plexus block after open shoulder surgery

BACKGROUND: This study compared the postoperative infusion of 1% lidocaine and 0.2% ropivacaine for continuous interscalene analgesia in patients undergoing open shoulder surgery. METHODS: Forty patients undergoing open shoulder surgery received an interscalene brachial plexus block with 30 ml of either 1.5% lidocaine (n = 20) or 0.5% ropivacaine (n = 20), followed by a continuous patient-controlled interscalene analgesia with 1% lidocaine or 0.2% ropivacaine, respectively. A blinded observer recorded the quality of analgesia and recovery of motor function during the first 24 h of infusion. RESULTS: Onset of the block occurred after 7.5 (5-40) min with lidocaine and 30 (10-60) min with ropivacaine (P = 0.0005). Postoperative pain intensity was higher with lidocaine than ropivacaine for the first 8 h of infusion. The ratio between boluses given and demanded from the pump was 0.5 (0.13-0.7) with lidocaine and 0.7 (0.4-1.0) with ropivacaine (P = 0.005). Rescue IV tramadol was required during the first 24 h of infusion by 16 patients of the lidocaine group (84%) and eight patients of the ropivacaine group (46%) (P = 0.05). At the 16 h and 24 h observation times a larger proportion of patients receiving ropivacaine had complete regression of motor block (70% and 95%) than patients receiving lidocaine (50% and 55%) (P = 0.05 and P = 0.013, respectively). CONCLUSIONS: Although 1% lidocaine can be effectively used for postoperative patient-controlled interscalene analgesia, 0.2% ropivacaine provides better pain relief and motor function.     

Patient-controlled regional analgesia (PCRA) with ropivacaine after arthroscopic subacromial decompression

BACKGROUND: The aim of the study was to evaluate postoperative analgesia and safety of wound instillation of ropivacaine either by a single dose or a patient-controlled regional anaesthesia (PCRA) technique. METHODS: In 40 patients undergoing arthroscopic subacromial decompression the surgeon placed a catheter into the subacromial space at the end of the operation. In Phase I (10 patients), ropivacaine 250 mg was injected twice within 1 h. In Phase II, 30 patients were randomised into three groups: group prilocaine-ropivacaine (PR) = 20 ml of 1% prilocaine-epinephrine injected preoperatively into the subacromial bursa + 20 ml of 0.5% ropivacaine infused in the catheter postoperatively; group saline-ropivacaine (SR) = saline-epinephrine (20 ml) preoperatively + 0.5% ropivacaine as in group PR; group saline-saline (SS) = saline-epinephrine (20 ml) preoperatively + saline postoperatively. The PCRA pump was filled with local anaesthetic or saline to allow boluses of 10-ml each, maximum one bolus/h, via the catheter. Pain relief, side-effects and venous plasma concentration of ropivacaine were evaluated during a 24-h-test period. RESULTS: The free plasma concentration of ropivacaine was 0.12 + 0.041 mg l-1 in Phase I. No adverse effects were seen. In Phase II pain at rest and on movement was lower in group PR than in group SS during the first 30 min postoperatively (P < 0.05). Group PR had the lowest morphine consumption (P < 0.05). Five to seven boluses were administered via the PCRA-pump, and 20 min after administration of the study solution, pain was lower in groups PR and SR compared with group SS (P < 0.001). CONCLUSIONS: Preoperative intrabursal prilocaine with epinephrine + postoperative subacromial administration of ropivacaine by PCRA-technique provided the most effective analgesia with no major side-effects. The free plasma concentrations of ropivacaine were far below toxic concentrations.     

A long-term continuous infusion via a sciatic catheter in a 3-year-old boy

We describe the case of a 3-year-old boy with a subtotal amputation of the right foot who received treatment for pain via a peripheral catheter positioned at the level of the sciatic nerve (lateral approach).We administered a continuous infusion of 0.2% ropivacaine, 0.4 mg x kg(-1) x h(-1) plus clonidine 0.12 microg x kg(-1) x h(-1) for 21 days. Pain relief was complete and the patient did not require any further rescue analgesia throughout the period even during medications and surgical treatment in our intensive care unit. We discuss the safety and efficacy of the use of a peripheral continuous infusion in children compared with other techniques of analgesia.     

Grand mal convulsion and plasma concentrations after intravascular injection of ropivacaine for axillary brachial plexus blockade

We report a patient to whom ropivacaine 1.1 mg kg^–1was administered for brachial plexus blockade and who developedgrand mal convulsions because of inadvertent i.v. injection.No symptoms of cardiovascular toxicity occurred. Venous bloodsamples were taken 15, 45, 75 and 155 min after the injection.The measured total plasma concentrations of ropivacaine were3.3, 1.6, 1.2 and 1.0 mg litre^–1 respectively.Initial plasma concentration after the end of the injectionperiod was estimated at 5.75 mg litre^–1 usinga two-compartment pharmacokinetic model. Br J Anaesth 2001; 87: 784–7     

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     

不同时机行硬膜外分娩镇痛对母婴的影响

目的研究不同时机行硬膜外分娩镇痛对母婴的影响。方法选择第一胎的足月初产妇,随机分为A、B、C、D 4组。A组为对照组,按产科常规处理。B组为宫口开至<1 cm行硬膜外自控镇痛。C组为宫口开至1~3 cm行硬膜外自控镇痛。D组为宫口开至3~5 cm行硬膜外自控镇痛。观察并记录镇痛效果(VAS)、下肢运动阻滞程度、产程时间、分娩方式、催产素的使用情况及新生儿Apgar评分。结果B、C、D组镇痛效果良好,各组静脉滴注催产素加强宫缩例数较A组多,均有显著性差异(P均<0.05)。B、C组潜伏期明显短于A组(P均<0.05),B组短于C组(P<0.05),活跃期只有B组短于A组(P<0.05);第二产程时间D组长于A组(P<0.05);第三产程时间各组均无显著性差异(P均>0.05)。B、C、D各组阴道自然分娩率和剖宫产率与A比较有显著性差异(P均<0.05)。产钳助产率、新生儿Apgar评分等情况与A组比较,无显著性差异(P>0.05)。B组产妇的总体满意度高于C、D 2组。结论第一产程早期行硬膜外自控镇痛效果确切,缩短产程,不影响新生儿,不增加剖宫产率,可以提高产妇的满意度。     

氯普鲁卡因及芬太尼缩短硬膜外罗哌卡因起效时间的临床观察

目的：探讨妇科手术患者复合氯普鲁卡因及芬太尼对罗哌卡因硬膜外麻醉起效时间的影响。方法：择期妇科手术患者60例，随机分为Rc，Rf，R三组，硬膜外分别给予0．75％罗哌卡因18ml＋氯普鲁卡因200mg＋生理盐水2ml；0．75％罗哌卡因18ml＋芬太尼0．1mg／2ml；0．75％罗哌卡因18ml＋生理盐水2ml。记录感觉阻滞最高平面、感觉阻滞起效时间、血流动力学改变及不良反应。结果：感觉阻滞平面迭T10的时问Rc、Rf组均明显短于R组，Rc组短于Rf组；最高阻滞平面Rc、Rf组均明显短于R组。结：论氯普鲁卡因200mg与芬太尼0．1mg均可缩短罗哌卡因硬膜外阻滞起效时间，且复合氯普鲁卡因200mg较芬太尼0．1mg起效时间更短。