ABSTRACT
BACKGROUND: Previous studies have demonstrated that lower local anaesthetic (LA) volumes can be used for ultrasound (US)-guided interscalene brachial plexus block (ISB). However, no study has examined whether US can reduce the volume required when compared with nerve stimulation (NS) for ISB. Our aim was to do this by comparing the minimum effective analgesic volumes (MEAVs). METHODS: After ethics approval and informed consent, patients undergoing shoulder surgery were recruited to this randomized, double-blind, up-down sequential allocation study. The volume used for both US and NS was dependent upon the success or failure of the previous block. Success was defined as a verbal rating score of 0/10, 30 min after surgery. Ten needle passes were allowed before defaulting to the opposite group. Patients received general anaesthesia. Pain scores and analgesic consumption were assessed by a blinded observer. Statistical comparisons of continuous variables were performed using Student's t-test and Mann-Whitney U-test as appropriate. Categorical variables were analysed using χ² test. MEAV values were estimated using log-transformed up-down independent pairs analysis and probit regression. Significance was assumed at P<0.05 (two-sided). RESULTS: The MEAV required to provide effective analgesia was significantly (P=0.034) reduced to 0.9 ml [95% confidence interval (CI) 0.3-2.8] in the US group from 5.4 ml (95% CI 3.4-8.6) in the NS group. Fewer needle passes were needed to identify the brachial plexus with US (1 vs 3; P<0.0001) and patients had less pain at 30 min after surgery (P=0.03). CONCLUSIONS: US reduces the number of attempts, LA volume, and postoperative pain when compared with NS for ISB.
Subject(s)
Anesthetics, Local/administration & dosage , Nerve Block/methods , Adult , Aged , Arthroscopy , Brachial Plexus/anatomy & histology , Brachial Plexus/diagnostic imaging , Brachial Plexus/physiology , Double-Blind Method , Drug Administration Schedule , Electric Stimulation/methods , Female , Fentanyl/administration & dosage , Humans , Male , Middle Aged , Pain Measurement/methods , Shoulder Joint/surgery , Ultrasonography, Interventional/methodsABSTRACT
Amastigotes, sphaeromastigotes, epimastigotes and trypomastigotes of Trypanosoma theileri, Laveran, 1902 have been observed in the nymphs and adults of Hyalomma anatolicum anatolicum (Koch, 1844). There ticks were obtained from engorged larvae and nymphs collected from a cross-bred bull with detectable parasitaemia. Infection with T. theileri was established in two 6-8-month old cross-bred calves by subcutaneous inoculation of Trypanosomatid flagellates collected from ticks and by feeding of the infected ticks on the ears of these calves.
