Bilateral transversus abdominis plane block as a sole anesthetic technique in emergency surgery for perforative peritonitis in a high risk patient
A 67-year-old woman, 55 kg was admitted to hospital with a 3-day history of abdominal pain, nausea and vomiting. She was diagnosed to have chronic obstructive pulmonary disease (COPD) 5 years ago and had four episodes of prior hospitalization secondary to acute exacerbation. She often required nebulisers and had an exercise tolerance of approximately 100 yards. In the week prior to admission she had received oral antibiotics and steroids for an infective exacerbation of COPD. On admission to the hospital she had signs of peritonitis and her abdomen was noted to be markedly distended. Ultrasonographic scan revealed a possible bowel (duodenal) perforation. She was tachypneic (RR 28/min) with evidence of accessory muscle use. Examination revealed reduced bi-basal air entry with crepitations all over the chest and chest X-ray showed consolidation of the right middle and lower lobe. Her arterial blood gas revealed type I respiratory failure (FiO2 0.60, pH 7.37, pO258 mmHg, pCO245 mmHg). Her heart rate was 112/min, and BP 90/60 mmHg. She was anemic with hemoglobin of 6 g%. S. urea - 102 and S. creatinine-2 g%. Intravenous acetaminophen was administered for pain relief, but despite this she could not cough or take deep inspiration due to ongoing pain. She was categorized as American society of anesthesiologists (ASA) physical status grade IV/E and was planned for emergency laparotomy. We planned to avoid general, epidural or spinal anesthesia, so we opted for TAP block under ultrasound guidance as a sole anesthetic technique. After proper explanation to the patient about the technique of TAP block, she was taken to operation theatre table and monitors attached. Pulse oximetry showed oxygen saturation of 88% on room air. Hence oxygen supplementation was carried out with venturi mask with oxygen flow at 6 L/min. Saturation improved to 92%. After securing an IV access with 18G (Gauge) needle on the right dorsum of the hand, she was sedated with intravenous dexmedetomidine infusion at 4 mcg/kg/min to make her comfortable, cooperative, and pain free for performing the block. Then she was laid supine with the anterolateral abdominal wall exposed bilaterally from the iliac crest to the sub-costal margins and scrubbed aseptically. The block was performed using an aseptic ultrasound guided in-plane technique (s-nerve sonosite, HFL38 (Company brand name of the 6.0 to 13.0 MHz linear probe) probe, 100 mm sonoplex needle). When the needle tip position is within the TAP neuro-fascial plane a mixture of 20 ml of 0.25% bupivacaine, 20 ml of 1% Lidocaine and 0.2 mg adrenaline was injected slowly through the needle. The same steps were repeated on the contra-lateral side. A remarkably good clinical effect was achieved within 30 min with almost complete resolution of pain. After 30 min, the abdominal incision was carried out without pain. All the vital signs remained normal intraoperatively. Effective coughing and deep breathing became possible and her tachypnea gradually resolved. Laparotomy revealed an ileal perforation, which was sealed with omentum. She made a slow post-operative recovery to be discharged from hospital 14 days after admission.