Selective neurogenic blockades and perioperative immune reactivity in patients undergoing lung resection

Abstract

Introduction: Pain is the most relevant factor for prolonged hospital stay after thoracic surgery and is associated with stress known to alter the Th1/Th2 ratio (Th = T helper cells) in the immediate postoperative period. Thoracic epidural block (TEB), central alpha 2 -receptor stimulation via intravenous clonidine application and stimulation of opioid receptors can decrease either pain and/or stress and might therefore influence this immune imbalance. The primary endpoint of the current study was the perioperative Th1/Th2 balance in lung surgery. The secondary endpoints aimed to the incidence of pain and pneumonia. Methods: After approval by the ethics committee and informed consent a total of 60 patients was randomized to receive double-blinded either remifentanil intravenously, or remifentanil + clonidine intravenously, or ropivacaine epidurally. Pain intensity was assessed by the numeric rating scale (NRS). The Th1/Th2 ratio was measured using a cytometric bead array. Pneumonia was diagnosed according to the hospital-acquired pneumonia criteria of the American Thoracic Society. Results: The Th1/Th2 ratio adjusted for baseline differed between groups over time (P = 0.012). At the end of surgery there was no significant difference between the remifentanil and the remifentanil + clonidine groups (P = 0.679) but a significantly lower ratio in the ropivacaine group compared with the remifentanil (P = 0.004) and the remifentanil + clonidine groups (P = 0.019). NRS scores immediately after surgery were lower in the ropivacaine group compared with the remifentanil group and the remifentanil + clonidine group but achieved only borderline statistical significance. None of the patients developed pneumonia. Conclusions: Intraoperative TEB decreases the Th1/Th2 ratio and provides better pain therapy immediately after surgery.