Efficacy of External Oblique Intercostal Block in Laparoscopic Bariatric Surgery

Is External Oblique Intercostal Block Under Enhanced Recovery After Bariatric Surgery (ERABS) Superior to Oblique Subcostal Transversus Abdominus Block? A Randomized Control Trial

Laparoscopic bariatric procedures nowadays are employed under ERAS protocol as an ambulatory surgery. Pain after laparoscopic procedures arises significantly from port site incisions in the anterior abdominal wall, and shoulder pain (referred from visceral pain). Narcotic medications are utilized to manage postoperative pain, but its disadvantages include, increased post-operative nausea and vomiting (PONV), ileus, sedation and delayed hospital discharge. Oblique subcostal transversus abdominis plane block (OSTAP) had been studied before and found to be effective in reducing post-operative morphine usage and produce good analgesia for about 24hours postoperatively. The ultrasound-guided external oblique intercostal (EOI) block is a new technique which proved to produce unilateral analgesia at thoracic dermatomes supplying the anterior and lateral aspects of the upper abdomen. The aim of this study was to test the hypothesis that US-guided EOI blocks can produce more reduction in opioid usage during the first 24 h after of laparoscopic bariatric surgeries when compared to oblique subcostal TAP (OSTAP) block.

Ultrasound-guided bilateral external oblique intercostal (EOI) using 30 ml of 0.25% bupivacaine hydrochloride and oblique subcostal transverse abdominis plane (OSTAP) block using Placebo (NSS 0.9%) 30 ml combined with bilateral posterior rectus sheath block with 15 ml bupivacaine 0.25%.

Ultrasound-guided bilateral oblique subcostal transverse abdominis plane (OSTAP) block using 30 ml of 0.25% bupivacaine hydrochloride and external oblique intercostal (EOI) using Placebo (NSS 0.9%) 30 ml combined with bilateral posterior rectus sheath block with 15 ml bupivacaine 0.25%.

EOI block:Under guidance of the linear high frequency transducer, sagittal plane between anterior axillary line and midclavicular line at the level of the 6th rib, In-plane approach between external oblique and intercostal muscles Hydrodissection with 30 ml of 0.25% bupivacaine hydrochloride .

OSTAP block: The needle was inserted in plane through the rectus adjacent to costal margin Once the tip of the needle was visualized in between the rectus muscle and transversus abdominus muscle and negative pressure aspiration was demonstrated, 30 ml bupivacaine 0.25% was deposited within the plane and hydrodissection was noted.

Posterior rectus sheath block: Under linear ultrasound probe, the needle was advanced gradually through the rectus muscle posteriorly toward its medial edge, approaching the rectus sheath. After negative aspiration,12.5 mL bupivacaine 0.25% was injected until the rectus muscle was separated from the posterior rectus sheath by hydrodissection.

Numerical rating scale (NRS) in the PACU, and on arrival to the ward at 0 hours then at 2, 4, 6, 12, and 24 hours postoperatively(NRS) with 0 = no pain, to 100mm = the worst imaginable pain at the specified time.

Quality of recovery 40 score at 24 hours.Twelve questions measured the comfort state; 9 questions measured the emotional state; 7 questions measured the psychological state; 5 questions measured the physical independence and 7 questions measured the level of pain. Each question received a score of 1 to 5 with a worst possible score of 40 and a best possible score of 200

time to readiness for discharge were measured according to the modified postoperative discharge scoring system (PADSS). Patients were considered eligible for discharge if they achieved a total score ≥ 9 on the condition that the vital signs parameter score was not less than 2, and none of the other five parameters scored a zero

Inclusion Criteria: age of 18 and 65; American Society of Anesthesia (ASA) class II or III elective laparoscopic bariatric procedure through trocars positioned at or above the um-bilicus (T10 dermatome). Exclusion Criteria: preoperative chronic use or contraindication to opioid or NSAID allergy to bupivacaine local skin infection at the injection site of EOI or OSTAP blocks liver or renal insufficiency psychiatric, or neurological disease prior open abdominal surgery above T10 dermatome patients converted to open surgery; and patients expected to be subjected to more tissue trauma.