Supplementation of retrobulbar block with clonidine in vitreoretinal surgery: effect on postoperative pain.

STUDY OBJECTIVE: To evaluate the effect of clonidine when added to local anesthetics on duration of postoperative analgesia during retrobulbar block. DESIGN: Prospective, randomized controlled trial. SETTING: Operating room and Postanesthesia Care Unit of a university-affiliated hospital. SUBJECTS: 80 ASA physical status 1, 2, and 3 patients undergoing vitreoretinal surgery with or without scleral buckling. INTERVENTIONS: Patients in the control group (n = 40) received a retrobulbar block with 4.5 mL of lidocaine-bupivacaine and 0.5 mL of saline. Clonidine group patients (n = 40) received 4.5 mL of lidocaine-bupivacaine and 0.5 µg/kg of clonidine in a 0.5 mL volume. MEASUREMENTS: The time to first analgesic request, frequency of postoperative pain, and number of postoperative analgesic requests per patient were assessed. MAIN RESULTS: 37 patients in the control group (92.5%) versus 24 patients (60%) in the clonidine group reported pain postoperatively (P = 0.001), with a shorter time to first analgesic request noted in the control group (4.9 ± 3 vs 11.9 ± 5.3 hrs; P < 0.001). The median number of postoperative analgesic requests per patient during the first 24 hours was higher in the control group than the clonidine group [2 (0-3) vs. 1 (0-3); P < 0.001]. CONCLUSIONS: The addition of clonidine 0.5 µg/kg to the local anesthetics of a retrobulbar block for vitreoretinal surgery decreases the frequency of postoperative pain and prolongs the time of analgesia.

Unusual case of difficult double-lumen endotracheal tube removal.

A reusable Robertshaw red rubber double-lumen endotracheal tube (DLT) was placed to facilitate lung isolation for thoracoscopy in a 49-year-old atopic patient. In spite of its smooth insertion, it was then not possible to remove the DLT. Direct laryngoscopy showed severe laryngeal edema. After 48 hours of medical treatment with steroids, the trachea was extubated. The laryngeal edema could have been the result of physical and chemical irritation by the reusable rubber DLT itself, or from the substances formed during repeated cleaning and sterilization of the DLT. Atopic patients who are prone to developing latex allergy are also more liable to develop severe reactions to chemical, mechanical, and physical irritation from reusable red rubber DLTs or from the chemical solution used for its cleaning and sterilization.