A prospective study of analgesia efficacy and plasma repiracaine concentration after pecs II block in patient undergoing mastectomy / Khaw Soon Keong

• Main Author: Khaw , Soon Keong
• Format: Thesis
• Published: 2017
• Subjects: R Medicine (General)
• Online Access: http://studentsrepo.um.edu.my/8889/4/A_prospective_study_of_analgesia_efficacy_and_plasma_repiracaine_concentration_after_pecs_II_block_in_patient_undergoing_mastectomy..pdf; http://studentsrepo.um.edu.my/8889/

Background and Objective: The introduction of novel ultrasound guided Pecs block has changed the choice for providing anaesthesia and/or analgesia to the upper part of the anterior chest wall. This technique was later adapted (PECS II block) to provide better coverage for more extensive procedures, especially involving the axilla. We would like to conduct a prospective descriptive study to masure the safety level of Ropivacaine and the analgesic efficacy for PECS II block using 30ml Ropivacaine 0.5%. Method: After obtaining approval from the UMMC Medical Research Ethics Committee (20165-2443) and written informed general anaesthesia (GA) and regional block consent, adult female patients undergoing unilateral mastectomy with axillary clearance were prospectively enrolled. PECS II block was performed with ultrasound guidance before induction of anaesthesia, and chronological blood samples were obtained by a piration from a large bore venous cannula specifically placed in the antecubital fossa. All participants received a total dose of R pivacaine not more than 3mg/kg, which is diluted with 0.9% saline to constitute 30ml of Ropi a aine 0.5% solution concentration. Venous blood was sampled from the blood taking canulla at I 0, 20, 30, 45, 60, 90, and 120 minute after Ropivacaine administration. Plasma Ropivacaine concentration was measured with liquid chromatography- tandem mass spectrometry method at the Pharmacology department Medical Faculty, University Malaya. Results: There were 6 patient who successfully completed this study protocol; they were aged between 52 and 71 (mean 63) years old. The weight of the patients is between 54 and 70kg (mean 63kg). Total Ropivacaine used for every patient was fixed at l50mg. In our study, there were no signs of CVS or CNS toxicity seen in the patients during the study period. The mean peak venous plasma concentration (Cmax) was 2.12ug/ml (SD 0.41, range 1.80-2.61). The median time point of maximum concentration (Tmax) of Ropivacaine occurred at 37.5min (range 20-60 min). The highest individual venous plasma concentration (Cmax) was 2.61 ug/ml ocurred at 45 min. Conclusion: This study demonstrates that the use of 150mg Ropivacaine in the unilateral PECS II block in adult females is safe withou exceeding the toxic level. There were no patients reported to have signs or CNS and CVS toxicity.