The Role of Continuous Thoracic Paravertebral Block for Fast-track Anesthesia After Cardiac Surgery via Thoracotomy

Minimally invasive cardiac surgery via minithoracotomy (MICS) was devised to reduce morbidity because of its potentially less inflammatory response, reduced transfusion requirements and minimal scarring, reduced recovery times, and the consequent cost.1Mehta Y. Arora D. Sharma K.K. et al.Comparison of continuous thoracic epidural and paravertebral block for postoperative analgesia after robotic-assisted coronary artery bypass surgery.Ann Card Anaesth. 2008; 11: 91-96Crossref PubMed Scopus (55) Google Scholar Although this technique is associated with a smaller incision, the pain from thoracotomy persists. The management of postthoracotomy pain is very challenging and may diminish the advantage of this surgery. We report a case of a 32-year-old patient who underwent MICS for an atrial septal defect requiring cardiopulmonary bypass with attendant large-dose anticoagulation and received continuous analgesia through paravertebral blockade (BPV). Anesthesia was induced with titrated midazolam, fentanyl, etomidate, and cisatracurium. A double-lumen tube was inserted for one-lung ventilation. After induction, the patient was positioned in the left lateral decubitus position for the insertion of a catheter in the right paravertebral space at the level of T4-T5. Anesthesia was maintained with sevofluorane, a continuous IV infusion of remifentanil and cisatracurium, and boluses of midazolam. Before closing the incision, a bolus of 10 mL of 2.5% lidocaine was administered through the paravertebral catheter, and 1 g of paracetamol were given intravenously. The surgery was uneventful, and the patient was extubated in the operating room without incident. Patient-controlled analgesia with a continuous infusion of 0.2% ropivacaine at a rate of 7 mL/h and a bolus of 5 mL was given as soon as the patient was admitted to the intensive care unit. Additionally, 1 g of paracetamol was prescribed every 6 hours. The visual analog scale was used to assess the quality of analgesia, and data were collected at 1, 6, 24, and 48 hours after surgery and reported to be below 3. Analgesia through the BPV was maintained for 48 hours. The patient was discharged from the intensive care unit 24 hours later and from the hospital 5 days after surgery. There were no complications related to the paravertebral block (neurologic complications, hematomas, urinary retention, hemodynamic instability, or nausea and vomiting). Thoracic epidural analgesia (TEA) has long been the gold standard treatment for post-thoracotomy pain, but in cardiac surgery the role of the epidural is still debatable. Recently, there has been increased interest in alternative regional techniques,2Joshi G.P. Bonnet F. Shah R. et al.A systematic review of randomized trials evaluating regional techniques for postthoracotomy analgesia.Anesth Analg. 2008; 107: 1026-1040Crossref PubMed Scopus (459) Google Scholar particularly BPV analgesia in MICS via thoracotomy, which offers optimal pain control with a better side effects profile.3Davies R.G. Myles P.S. Graham J.M. A comparison of the analgesic efficacy and side-effects of paravertebral vs epidural blockade for thoracotomy—A systematic review and meta-analysis of randomized trials.Br J Anaesth. 2006; 96: 418-426Crossref PubMed Scopus (522) Google Scholar The choice of thoracic paravertebral analgesia over TEA was made to prevent the side effects of TEA in patients under full anticoagulation. The primary concern about neuraxial analgesia in cardiac surgery is the potential for spinal hematoma related to high doses of heparin; the incidence has been estimated to be from 1:150,000 to 1:1,528.4Ho A.M. Chung D.C. Joynt G.M. Neuraxial blockade and hematoma in cardiac surgery: Estimating the risk of a rare adverse event that has not (yet) occurred.Chest. 2000; 117: 551-555Crossref PubMed Scopus (211) Google Scholar As antithrombotic therapy becomes more frequently used in cardiac patients, epidural analgesia becomes riskier.5Poyhia R. Cardiac surgery: with or without epidurals?.Acta Anaesthesiol Scand. 2006; 50: 777-779Crossref PubMed Scopus (1) Google Scholar To date, no neuraxial hematomas have been reported after paravertebral blockade. The segmental unilateral blockade of the BPV provides unilateral sympathectomy in which hemodynamic repercussion is minimal compared with TEA. This is an important concern in the postoperative period of cardiac surgery because hemodynamic instability is not unusual and bilateral sympathetic blockade could make the management difficult. Other advantages of BPV are the safety when it is performed in sedated and ventilated patients6Daly D.J. Myles P.S. Update on the role of paravertebral blocks for thoracic surgery: Are they worth it?.Curr Opin Anaesthesiol. 2009; 22: 38-43Crossref PubMed Scopus (80) Google Scholar and the reduced incidence of pulmonary complications, urinary retention, and nausea and vomiting.3Davies R.G. Myles P.S. Graham J.M. A comparison of the analgesic efficacy and side-effects of paravertebral vs epidural blockade for thoracotomy—A systematic review and meta-analysis of randomized trials.Br J Anaesth. 2006; 96: 418-426Crossref PubMed Scopus (522) Google Scholar This letter emphasizes the role of BPV in cardiac surgery via thoracotomy, which allows fast-track recovery with acceptable pain control and a safe side effects profile in fully anticoagulated patients.