Changes in tissue oxygenation following caudal epidural blockade in infants and children

Adequate tissue oxygenation is required for effective white blood cell function and bactericidal activity. Decreased tissue oxygenation has been shown to be a risk factor for perioperative wound infections. Regional anesthetic techniques result in a functional sympathetic block and may increase tissue oxygenation. The purpose of the current study is to prospectively evaluate changes in tissue oxygenation using a non-invasive near-infrared spectroscopy (NIRS) device following caudal epidural block in infants and children.

Following standard anesthetic induction and general anesthesia with an endotracheal tube or laryngeal mask airway, the NIRS sensors were placed on two sites. One sensor was placed at a site affected by the caudal block (lower extremity), and the other sensor was placed on the arm, a site unaffected by the caudal block (upper extremity). The NIRS value was recorded at baseline and then again at 15, 30, and 45 min after the block. The caudal block was performed, after anesthetic induction and NIRS sensor placement, using bupivacaine 0.25% with epinephrine 1 : 200,000 or ropivacaine 0.2% with epinephrine 1 : 200,000 at a dose of 1 ml · kg(-1). The inspired oxygen concentration after induction was held constant at 30%, and anesthesia was maintained with sevoflurane at 1 MAC. No other pharmacologic agents were administered.

Following the caudal epidural block, there was a statistically significant increase in the tissue oxygenation from the affected site. The NIRS value increased from a baseline of 83 ± 4 to 87 ± 3 at 15 min (P = 0.0001 vs baseline), 88 ± 4 at 30 min (P < 0.0001 vs baseline), and 87 ± 4 at 45 min (P < 0.0001 vs baseline). No change was noted on the unaffected site (upper extremity).

There was a statistically significant increase in tissue oxygenation as measured by NIRS following caudal anesthesia in infants and children. Although the magnitude of the change was less, this study confirms the results of previous studies in adults showing an increase in tissue oxygenation following regional blockade.