Tetsuo Takiguchi

The effect of epidural saline injection on analgesic level during combined spinal and epidural anesthesia assessed clinically and myelographically

An epidural injection of physiological saline solution after spinal anesthesia may produce a higher level of analgesia than spinal anesthesia alone because of a volume effect.The purpose of this study was to clarify the volume effect caused by epidural injection of saline after spinal anesthesia. Twenty patients undergoing combined spinal and epidural anesthesia for elective surgery whose analgesic levels did not reach the surgical regions 10 min after spinal anesthesia at the L4-5 interspace were randomly assigned to two groups. The control group (n = 10) received no epidural saline injection. The saline group (n = 10) received 10 mL of saline through an epidural catheter at the L2-3 or L3-4 interspace 10 min after spinal anesthesia. In the saline group, the levels of analgesia 15 and 20 min after spinal anesthesia were significantly higher than those in the control group (P < 0.05). Next, we examined the volume effect of epidural injection of saline with myelography using two adult volunteers. In both volunteers, the upper level of the contrast medium, which was injected in the lumbar subarachnoid space, began to increase concurrently with lumbar epidural injection of saline, reaching from L3 to L1 and from L2 to T12. The diameter of the subarachnoid space diminished to less than 25% after injection of saline. We conclude that lumbar epidural injection of saline increases the analgesic level 10 min after spinal anesthesia, probably because of a volume effect. Implications: In this study, using surgical patients and volunteers, we determined that a lumbar epidural injection of physiological saline solution 10 min after spinal anesthesia produces a higher analgesic level than spinal anesthesia alone because of a volume effect. (Anesth Analg 1997;85:1097-100)

Pediatric caudal block with mepivacaine, bupivacaine or a mixture of both drugs: requirement for postoperative analgesia and plasma concentration of local anesthetics

STUDY OBJECTIVES To assess the effects of pediatric caudal block using mepivacaine, bupivacaine, or a mixture of both drugs on postoperative analgesia, and to examine plasma concentrations of the local anesthetics after caudal injection. DESIGN Prospective, randomized, double-blind study. SETTING Operating room and pediatric surgical ward. PATIENTS 60 ASA physical status I children weighing 10 to 20 kg (26 females, 34 males), and scheduled for inguinal herniorrhaphy. INTERVENTIONS Patients randomly received caudal block with 1 mL/kg of mepivacaine 1% (Group M, n = 20), 1 mL/kg of bupivacaine 0.25% (Group B, n = 20), or a mixture of 0.5 mL/kg of mepivacaine 1% and 0.5 mL/kg of bupivacaine 0.25% (Group MB, n = 20) after induction of anesthesia with sevoflurane in 50% oxygen (O2). Anesthesia was maintained with 66% nitrous oxide in O2 supplemented with sevoflurane at an end-tidal concentration of less than 1%. MEASUREMENTS AND MAIN RESULTS Postoperative pain scores using a pediatric pain scale and plasma concentration of each local anesthetic were measured. In Group M, four patients required postoperative analgesics within the first 24 hours. However, no patients required postoperative analgesics in Groups B and MB. In Group M, the plasma concentration of mepivacaine of two patients exceeded 5 microg/kg of the level of toxicity. However, these patients did not show any toxic symptoms. Because a mixture of two local anesthetics halves the concentration of each local anesthetic, the plasma concentrations of mepivacaine and bupivacaine in Group MB were significantly lower than those of Groups M and B. CONCLUSIONS Pediatric caudal block with a mixture of mepivacaine and bupivacaine is effective for intraoperative and postoperative analgesia.

Excision of spinal tumor in a patient with severe pulmonary dysfunction using combined spinal and epidural anesthesia with two epidural catheters

BACKGROUND AND OBJECTIVES Combined spinal and epidural anesthesia (CSEA) has become common practice. We performed CSEA using two epidural catheters in a 69-year-old female with severe pulmonary dysfunction caused by a diaphragmatic hernia, who underwent surgical excision of a lumbar spinal tumor. METHODS Combined spinal and epidural anesthesia was performed using two epidural catheters to minimize postoperative pulmonary complications. One epidural catheter was inserted above the surgical region, at the T11-12 interspace, and another one below the surgical region, via the sacral hiatus. Spinal anesthesia was produced using the L5-S1 interspace and 3 mL 0.5% bupivacaine. Oxygen, 3 L/min, was administered through a face mask during surgery. RESULTS Fifteen minutes after spinal anesthesia, analgesic level was confirmed below T7 using the pinprick method. The patient complained of pain in the surgical region 10 minutes after the dura mater was opened. We injected 5 mL 2% mepivacaine through the upper epidural catheter to relieve the pain. We also injected 10 mL 2% mepivacaine through the lower catheter when she felt pain in the right leg. The perioperative course was uneventful. Oxygen saturation was maintained above 95%. CONCLUSIONS Combined spinal and epidural anesthesia using two epidural catheters was used successfully to excise a spinal tumor in a patient with severe pulmonary dysfunction.