2025, Vol. 8, Issue 4, Part A

Background: The ultrasound-guided Transversus Abdominis Plane (TAP) block is utilized for postoperative pain relief after inguinal hernia repair and appendectomy procedures. The implementation of an injection pressure monitoring device is believed to improve the accuracy of local anesthetic placement within the TAP plane. This study aims to determine whether monitoring the injection pressure of local anesthetic affects the precision of TAP blocks.
Patient and Methods: Thirty patients aged between 18 and 65 years with ASA physical status classes 1 and 2 were enrolled 10 undergoing elective inguinal hernia repair and the remaining patients for emergency appendectomy. Following surgical completion, all participants received an ultrasound-guided TAP block using a mixture of 20 mL bupivacaine (0.5%) mixed with normal saline (0.9%). Injection pressure was monitored via a disposable pressure manometer while continuous ultrasound imaging tracked pain scores alongside vital signs including pulse rate and blood pressure during postoperative recovery.
Results: The findings indicated that all intramuscular injections required low pressures (< 15 psi), whereas intrafascial injections necessitated intermediate pressures (15-20 psi). Postoperative pain assessments showed that at zero hours post-injection (immediately after surgery), 86.7% of patients reported no pain while 13.3% experienced mild discomfort (scores of 1-3). One hour later and again at three hours post-surgery, 80% reported no pain with similar mild pain levels observed in the remaining cohort. At six hours post-procedure: 56.7% reported no pain while 36.7% noted mild discomfort.
Conclusion: For effective analgesia during TAP blocks administered through intrafascial injection requires an intermediate pressure range of 15-20 psi; conversely for intramuscular injections a pressure below 15 psi suffices. Utilizing injection pressure monitoring significantly enhances the localization accuracy of anesthetic deposition thereby improving analgesic efficacy when combined with ultrasound guidance.