Analgesic Effect of Morphine Added to Bupivacaine in Serratus Anterior Plane Block Following Modified Radical Mastectomy. Only a Local Effect? Randomized Clinical Trial
Received 29 October 2019
Accepted for publication 7 March 2020
Published 31 March 2020 Volume 2020:13 Pages 661—668
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr E Alfonso Romero-Sandoval
Fatma A El Sherif,1 Ahmad M Abd El-Rahman,1 Ahmed H Othman,1 Samia A Shouman,2 Mervat M Omran,3 Nivin A Hassan,4 Sahar B Hassan,5 Ebrahim Aboeleuon6
1Anesthesia, ICU, and Pain Relief, South Egypt Cancer Institute, Assiut University, Assiut, Egypt; 2Cancer Biology, National Cancer Institute, Cairo University, Cairo, Egypt; 3Cancer Biology (Pharmacology and Experimental Oncology), National Cancer Institute, Cairo University, Cairo, Egypt; 4Cancer Biology (Pharmacology and Experimental Oncology), South Egypt Cancer Institute, Assuit University, Assiut, Egypt; 5Clinical Pharmacy, Faculty of Pharmacy, Assuit University, Assiut, Egypt; 6Surgical Oncology, South Egypt Cancer Institute, Assiut University, Assiut, Egypt
Correspondence: Ahmed H Othman Tel +20 1005098394
Fax +20 88 2086609
Background: Serratus anterior plane (SAP) block, a novel regional anesthetic procedure, involves the anterolateral chest wall. Opioid receptors have been found on peripheral nerve terminals, so morphine may have a local action.
Objective: This work aimed at exploring the analgesic efficacy of morphine added to bupivacaine in SAPB in patients for whom modified radical mastectomy was conducted and whether it is a mere local effect.
Methods: Forty female patients were planned to have modified radical mastectomy participated in the study. Patients were randomly divided into two groups; Control group (C): received ultrasound-guided serratus anterior plane block with 20 mL of bupivacaine hydrochloride 0.25%; Morphine group (M): received the same in addition to 10 mg morphine sulfate. Intra- and post-operative blood samples were taken for the assessment of morphine serum levels. All patients were assessed for VAS scores during rest and movement (VAS-R and VAS-M). Time to the first request and the total amount of the rescue analgesia were recorded.
Results: In group M, Morphine was not detected in the plasma of all patients. Both VAS-R and VAS-M were significantly higher in group C than in group M (P< 0.001) and (P≤ 0.003), respectively. Time to the first request of rescue analgesia was 8.5 h in group C compared to 20 h in group M (P=0.005) with a median dose of acetaminophen consumption of 2 g in group C compared to 1 g in group M (P=0.006).
Conclusion: Ten mg of morphine, when added to bupivacaine in SAPB, improved postoperative analgesia in patients to whom modified radical mastectomy was conducted. This effect seems to be attributed merely to local mechanisms.
Registration: The registration number of this study is NCT02962024 at www.clinicaltrial.gov.
Keywords: analgesic, morphine, bupivacaine, serratus anterior, modified radical mastectomy
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