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

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 α2-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.