Interscalene Versus Combined Infraclavicular-suprascapular Nerve Blocks

Postoperative Pain

Interscalene block, Postoperative analgesia, Suprascapular nerve block, Infraclavicular nerve block, Arthroscopic rotator cuff repair, Hemi-diaphragmatic paralysis

The aim of this trial is to compare the analgesic efficiency and hemi-diaphragmatic paralysis of the standard ultrasound-guided interscalene (ISB) brachial plexus block with the combined use of costoclavicular approach of infraclavicular brachial plexus block and suprascapular nerve block (ICB-SSB) for patients undergoing arthroscopic rotator cuff repair. Authors hypothesize that the combined use of ICB-SSB could lead to equivalent postoperative analgesic effect to the standard ISB with less hemi-diaphragmatic paralysis.

The interscalene block main hindrance is the high risk of ipsilateral phrenic nerve block with sequential hemi-diaphragmatic paralysis.The combined use of conventional paracoracoid infraclavicular block (ICB) and suprascapular block (SSB) was not equivalent to the standard ISB regarding the analgesic efficacy , but has no hemi-diaphragmatic affection for patients undergone shoulder arthroscopic procedures.ICB can be achieved by another approach (costoclavicular) which blocks the brachial plexus at the mid infraclavicular fossa The patients scheduled for an elective arthroscopic rotator cuff repair will be randomly allocated by a computer-gener¬ated table into one of two study groups. The randomization sequence will be concealed in opaque sealed envelopes. The envelopes will be opened by the study investigators just after recruitments and admission to the operation room. Only assessors and data collectors will be blinded to the groups allocations. Preoperative preparation: Preoperative investigations will be done according to the local protocol designed to evaluate the patients. It includes complete blood count, blood sugar level, serum urea and creatinine, liver function tests, coagulation profile and electrocardiogram (ECG). Intraoperative Management of Patients: After arrival to the induction room, a 20G intravenous catheter will be placed in the upper limb opposite to the surgical site, and intravenous premedication (midazolam 2 mg and fentanyl 50 µg) will be administered to all patients. Supplemental oxygen (nasal cannulae at 2 Lmin-1), standard ASA monitoring (5-lead ECG, noninvasive blood pressure (NIBP), and pulse oximetry) will be applied throughout the procedure. All blocks will be performed under real-time ultrasound guidance (Philips clear vue350, Philips healthcare, Andover MA01810, USA). The patients in both groups will initially receive superficial cervical plexus block. The block will be performed in supine position with the patients' head turned to the other side. Once the skin is appropriately cleaned and prepared with anti-septic, the high frequency linear array transducer (8-15 megahertz) will be placed over the lateral side of the neck at the midpoint of the posterior border of the sternocleidomastoid muscle(SCM). The transducer is positioned such that the tapering end (posterior border on the ultrasound image) of the SCM is in the center of the screen. The block needle (22-gauge, 50 mm, Stimuplex D®; B Braun, Germany) is then introduced from the posterior aspect through the skin and platysma and 10 ml of local anesthetic(LA) deposited just behind this landmark. Afterthat the patients will receive either ISB or ICB-SSB. Following completion of the assessments of sensorimotor blocks at 30 min (see below), induction of general anesthesia will be achieved by intravenous propofol 1.5-2 mgkg-1, fentanyl 1 ugkg-1, and atracurium 0.5 mgkg-1. General anesthesia will be maintained by isoflurane 1.5 volume % in 2 lmin-1 oxygen-air mixture 50:50 and atracurium 0.1 mgkg-1 every 30 minutes. All subjects will be placed in the beach chair position slowly, and the surgical procedures will be completed by the same surgical team. Intraoperatively, if the patient's heart rate or blood pressure exceeded 20% of the preoperative value, a 50-µg bolus dose of fentanyl will be administered. Deliberate hypotension technique will be used to keep systolic blood pressure at 90-100 mmHg range, mean blood pressure at 65-75 mmHg range, and heart rate at 60-70 bpm range by nitroglycerine intravenous infusion at a rate of 1-2 µgkg-1min-1. If excessive unwanted hypotension (systolic blood pressure less than 90 mmHg or mean blood pressure less than 65 mmHg) will be noted, 200 ml ringer acetate fluid bolus will be administered to regain the blood pressure to the desired range with reducing the infusion rate of nitroglycerine or stop it temporarily. Otherwise, 5 mg ephedrine increments will be used to secure save blood pressure readings range. Bradycardia (HR less than 50 bpm) will be corrected by atropine sulphate administration at a dose of 30 µg increments. Assessment of Sensory and Motor Blockade: * The extent of motor and sensory blockade will be evaluated by an anesthesiologist who will not be involved in the brachial plexus block 30 min after local anesthetics administration. Using an alcohol swab, the sensory blockade will be tested on the skin overlying the clavicle (supraclavicular nerves) and the lateral surface of the deltoid (axillary nerve). Each territory will be graded according to a three-point scale using a cold test: 0 = no block; 1 = analgesia (patient can feel touch, not cold); 2 = anesthesia (patient cannot feel touch). * Motor function will be tested using shoulder abduction (axillary and suprascapular nerves) and external shoulder rotation (suprascapular nerve) according a three-point scale: 0 = no block; 1 = paresis; 2 = paralysis. blocks will be considered complete if, at 30 min, a global composite score six points (out of a maximum of eight points) will be achieved,5 incidence of complete block 30 minutes after injection will be recoded. Assessment of hemi-diaphragmatic paralysis (HDP) using Ultrasound: Ultrasound evaluation of the hemi-diaphragm will be assessed by a blinded trained radiologist. A low-frequency (2 to 5 MHz) curvilinear array transducer will be placed in the coronal plane at the midaxillary line to obtain an intercostal view. At the level of ribs eight to nine on the left and seven to eight on the right, the spleen or liver are centered with the rib shadows on either side. On deep inspiration, caudal descent of the liver or spleen precedes descent of the bright pleural line. The transducer will then be moved in both caudal and cephalad directions to visualize the end-inspiratory and end-expiratory levels of the pleural line, respectively, which will be then marked on the patient's skin. This process will be repeated before, after the chosen regional anesthetic technique and after recovery from general anesthesia in post-anesthetic care unit (PACU) with the patient in the same position. Minimal change signifies no block, but a reduction in this distance represents phrenic nerve block. Postoperative Evaluation: After completion of the surgical procedure, the patients extubated after fulfilment of the extubation criteria and then will be transferred to PACU for 2 h assessment. At PACU all patients will receive ketoprofen 100 mg and acetaminophen 1 gram by intravenous infusion over 30 min. Postoperative pain will be rated on a numerical scale ranging (NRS) from 0 (no pain) to 10 (worst imaginable pain) at 1-hr at PACU then at 4, 8, 12, and 24 hours postoperatively. The patients discharged to ward after fulfilment of discharge criteria and modified Aldrete score ≥9. ketoprofen 100 mg/12 h and acetaminophen 1 gram/8 h by intravenous infusion over 30 min will be continued for 48 h as parts of the postoperative pain control policy of the institution. Assessment of postoperative analgesia duration by recording the time of first request of analgesia. The duration of anesthesia time (defined as the time between the end of the local anesthetic injection for brachial plexus block and the postoperative administration of analgesic agents) will be recorded. Patients with NRS\>5 will receive morphine sulphate IV at a bolus dose of 2-5 mg increments with maximum dose of 20 mg at 4 hours or 40 mg at 24 hours. Cumulative and interval amount of morphine consumption in 24 h will be recorded.

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