The ultrasound-guided rectus sheath block as an anaesthetic in adult paraumbilical hernia repair.
The patient was a wheelchair bound, 83-year-old woman with multiple co-morbidities including Type 2 diabetes (complicated by diabetic nephropathy), hypertension, hyperlipidaemia and ischaemic cardiomyopathy. She had been hospitalised several times for pulmonary oedema. Her most recent echocardiographic examination demonstrated a left ventricular ejection fraction of 15% and segmental wall motion abnormalities at rest. In addition, she had documented cervical myelopathy for which she had been treated conservatively. She presented with small bowel obstruction which was attributed to a small paraumbilical hernia and a mesh repair was planned accordingly.
We elected to perform the surgery under a bilateral rectus sheath block with judicious sedation in an effort to minimise haemodynamic instability. She was sedated with a very small dose of intravenous ketamine (10 mg) and midazolam (0.5 mg) prior to the blocks, which were well tolerated. The rectus sheath block was performed with real-time ultrasound guidance (38 mm broadband linear array, Sonosite Micromaxx[TM], SonoSite Inc., Bothell WA, USA). A simple 23 G hypodermic needle was used in a cross-sectional, out-of-plane approach to the rectus sheath. Ten ml of 0.5% bupivacaine and 5 ml of 1% lignocaine (with adrenaline) were then deposited in the potential space between the rectus abdominis muscle and the posterior rectus sheath (Figure 1).
Surgery was commenced and a low-dose propofol infusion was started for further sedation. A small dose of intravenous fentanyl (25 [micro]g), midazolam (0.5 mg) and ketamine (10 mg) was required during surgical reduction of the hernia due to bowel manipulation. The surgical incision was not large and no further analgesics were needed during the 90 minute surgery. The patient remained haemodynamically stable throughout the surgery, all variables remaining within 15% of baseline. She was monitored in the post-anaesthetic care unit after surgery and discharged to the ward within an hour without requiring any further analgesics.
[FIGURE 1 OMITTED]
The rectus sheath block anaesthetises the 9th, 10th and 11th intercostal nerves in its course through the rectus sheath. This provides somatic anaesthesia to the abdomen, sufficient for umbilical surgery or minor surgery in its immediate vicinity. Avoiding the physiological sympathectomy associated with central neuraxial blockade minimises the haemodynamic fluctuations associated with such blocks. Even incisions in the suprapubic region may derive some analgesic benefit, especially if supplemented with ilioinguinal blocks (4).
Ultrasonography provides non-invasive real-time imaging of the anatomy for rectus sheath blocks. This may, logically, increase the success rate and reduce the incidence of inadvertent needle entry into the peritoneum, vascular or bowel injury.
We believe that this often-overlooked block remains a useful tool in modern day practice. While the risks of bowel and vessel injury have to be acknowledged, these are greatly reduced by the accurate placement of the needle under direct, real-time ultrasonography.
With ultrasound imaging becoming increasingly available in anaesthetic practice, the rectus sheath block could play a more prominent role in the provision of anaesthesia and analgesia in selected patients.
(1.) Schleich CL. Schmerzlose Operationen. Fourth ed. J. Springer 1899; p. 240.
(2.) Ferguson S, Thomas V, Lewis I. The rectus sheath block in paediatric anaesthesia: new indications for an old technique? Paediatr Anaesth 1997; 6:463-466.
(3.) Willschke H, Bosenberg A, Marhofer P, Johnston S, Kettner SC, Wanzel O et al. Ultrasonography-guided rectus sheath block in paediatric anaesthesia--a new approach to an old technique. Br J Anaesth 2006; 97:244-249.
(4.) Yentis SM, Hills-Wright P, Potparic O. Development and evaluation of combined rectus sheath and ilioinguinal blocks for abdominal gynaecological surgery. Anaesthesia 2000; 54:475-479.
(5.) Muir J, Ferguson S. The rectus sheath block--well worth remembering. Anaesthesia 1996; 51: 893-894.
Changi General Hospital, Singapore
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|Author:||Phua, D.S.K.; Phoo, J.W.H.; Koay, C.K.|
|Publication:||Anaesthesia and Intensive Care|
|Date:||May 1, 2009|
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