Abstract ID: A02
Abstract Title: US Guided Rectus Sheath Block In Children. An Initial Experience.
Poster Type: Poster
ABSTRACT BODY
Introduction:The rectus sheath block (RSB) has been proven to provide prolonged analgesia for umbilical hernia repair and for laparoscopic procedures(1-4). The RSB is an easily performed block with a low risk of side effects (5,6). A practical problem that is faced by pediatric anesthesiologists is the identification of the correct tissue planes and confirmation of the needle position in the rectus sheath. The tissue planes tend to be thin and the surface anatomy is less well defined in children. This may decrease the efficacy of the RSB. To improve accuracy of needle placement in the rectus sheath we used an ultrasound-guided technique in children. We report our experience of ultrasound guided RSB in children.
Methods: After receiving institutional research ethics board approval we performed RSB under ultrasound visualization of tissue planes and the needle. Patients undergoing midline abdominal surgery at our institution were included in our study. Exclusion criteria were infection in the rectus muscle, congenital abdominal structural defect, or severe coagulopathy. An ultrasound of the abdominal wall was performed using iLook ® US monitor (SonoSite mc, Bothell, WA, USA). Tissue planes were identified. A measurement of depth and thickness of the rectus sheath (RS) was recorded. A 25G needle was introduced from the lateral border of the rectus sheath in line with the US beam. The needle tip was introduced inside the rectus sheath. After negative aspiration for blood and air, a volume of 1 ml of local anesthetic (LA) was injected and spread of LA was observed under US. Afterwards ropivacaine 0.2%, 0.2 ml/kg (max 10 ml) was injected. Descriptive statistics were generated to summarize participant’s characteristics and relationship between age of the children and rectus sheath depth was established using Kendall’s correlation coefficient.
Results: We performed RS blocks in 50 children aged between 1.17 and 17 years (median 6.0 years); median weight of 22.5kg (range: 7-63). 54% of the participants were males. Surgery types mainly performed were: laparoscopic appendectomy (36%), umbilical hernia repair (36%), diagnostic laparoscopy (6%), epigastric hernia repair (6%), and laparoscopic fundoplication (6%). We experienced good visualization of subcutaneous tissue, fat, anterior and posterior extent of rectus sheath, and rectus muscle. Bowel loops were also identified on US scan. Needle localization was accurate in all occasions at the first attempt. Local anesthetic spread was seen as the Rectus muscle expanded with the injection. Observed rectus sheaths had a median depth of 5.0 cm (range 2.5 to 10.0) and was moderately correlated with age (r = 0.5 84, p< 0.00 1).
Discussion: Use of ultrasound to localize rectus sheath muscle in children is a useful tool. In our experience we were able to successfully place the needle in the rectus sheath at the first attempt with ease and accuracy. We suggest use of US monitor for localization and guidance of needle for RSB. Use of US will help avoid placement of needle in undesirable locations in children such as into subcutaneous fat, the peritoneum, and bowel loops.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A02