Adding Dexmedetomidine to Methylene Blue in Thoracic Paravertebral Block for Video-Assisted Lobectomy: A Case Series Study.

Abstract

Purpose: Thoracic surgery often results in severe chronic postoperative pain. Current evidence favors two locoregional techniques. Thoracic Epidural Anesthesia (TEA), the gold standard, and Thoracic Paravertebral Block (TPVB), which is associated with fewer side effects but is limited by short duration of action of local anesthetics (LA) and potential failure due to improper drug distribution. This study investigates the use of dexmedetomidine (DEX) as adjuvant to prolong the effects of LA in TPVB, with methylene blue used for visual confirmation of accurate injectate spread.

Patients and methods: We observed 6 patients undergoing Video-Assisted Thoracoscopy (VATS) lobectomy who received TPVB with ropivacaine, DEX and methylene blue. The primary endpoint was postoperative pain recorded at 1, 12, 24, 48 hours using Numeric Rating Scale (NRS); the secondary endpoints were cumulative opioid consumption in the first 24 hours in Milligram Morphine Equivalents (MME); adverse events: occurrence of bradycardia, hypotension, Postoperative Nausea and Vomiting (PONV); length of hospital stay. All patients completed the study.

Results: Our results showed optimal pain scores, with NRS scores always below 4, decreased need for opioids, and prolonged analgesia. None of the patients had bradycardia nor PONV, but two patients experienced acute and self-limited hypotension following TPVB.

Conclusion: Thoracic Paravertebral Block with Dexmedetomidine and methylene blue was effective and safe in controlling postoperative pain. Methylene blue could help improving knowledge on anesthetics distribution to reduce failure rates.