Rectus Sheath Block Versus Thoracic Epidural Effect on Diaphragmatic Function After Elective Midline Abdominal Surgery (Rectus)

Rectus Sheath Block Versus Thoracic Epidural Effect on Diaphragmatic Function After Elective Midline Abdominal Surgery

Comparison of the Effect of Rectus Sheath Block Versus Thoracic Epidural Analgesia on Diaphragmatic Function After Elective Abdominal Surgery With Midline Incision

This study will be undertaken to compare the respiratory and analgesic effects of thoracic epidural versus ultrasound guided rectus sheath block analgesia after elective abdominal surgery with midline incision.

A major proportion of pain experienced by patients undergoing abdominal surgeries is due to somatic pain signals derived from the abdominal wall. The central portion of anterior abdominal wall components (skin, muscles and parietal peritoneum) is innervated by sensory neurons branching from the anterior rami of spinal nerves T7 to T1. These neurons lie between the rectus abdominis muscle and posterior rectus sheath, and pierce the rectus muscle close to the midline. The tendinous intersections of the rectus muscle do not fuse with the posterior rectus sheath, thereby allowing the injectate to spread cephalo-caudally within this potential space. Rectus sheath (RS) block has been described for any midline abdominal incisions (epigastric and umbilical hernia repairs). As visceral pain becomes attenuated by the 2nd postoperative day, rectus sheath block can also be administered for midline laparotomy. As a single bolus of the local anesthetic has a maximum duration of 12 hours. it is necessary to insert a catheter into this space to allow either a continuous infusion of local anesthetic, or repeated boluses of local anesthetic every 8 to 12 hours for 48 to 72 hours post-operatively. However, the effects of rectus sheath block catheter analgesia on the respiratory function after abdominal surgery with midline incisions are still under investigation.

Patients will receive ultrasound-guided rectus sheath block with catheter insertion performed after induction of general anesthesia and before surgery.

Sonar guided RSC will be performed using a 16-G, 8-cm TuohyUpon reaching this potential space, after careful aspiration.

Sonar-guided epidurals will be performed with a 17-gauge Tuohy needle and 19 G flex-tip catheter. Using an LOR (loss of resistance) to saline technique, catheters will be inserted 4 cm into the epidural space and a suitable test dose will be administered to exclude intravascular or sub-arachnoid injection.

The measurements of diaphragmatic motion will be attained at the posterior surface of the diaphragm. From the tracings on M-mode, the distance between echogenic lines (DIA) in centimeters and diaphragmatic inspiratory/expiratory velocity in centimeters/second during quiet, deep, and sniff breathing will be measured on the frozen images.

Verbal rating pain scale (VRS) (Ranging from 0 to 4), where 0=no pain, 1=mild pain, 2=moderate pain, 3=severe pain and lastly 4 =excruciating pain) will be recorded at rest and upon patient coughing; on admission to PACU (baseline), and 2, 4, 6, 12, and 48h postoperatively.

Measurements of Forced vital capacity (FVC) will be measured by the use of hand-held spirometer (One-flow®, Clement Clarke, U.K). At each assessment, the largest values of FVC will be recorded.

Inclusion Criteria: Age: 18-50 years. Sex: both males and females. BMI< 30kg/m2. ASA physical status: 1, II and III. Elective abdominal surgery with midline incisions. Exclusion Criteria: Patient refusal. Infection at injection site Coagulation disorders. Allergy to study medications. Pregnancy. Respiratory tract infection within the last 2 weeks. Urgent abdominal surgery

Professor in anesthesia and intensive care department, faculty of medicine, Assiut university, Egypt.