The effect of cisatracurium and rocuronium on cisatracurium precurarization and the priming principle.

STUDY OBJECTIVE: To demonstrate the effect of administering a precurarizing dose of cisatracurium or rocuronium on the speed of onset of cisatracurium, and to review the possible mechanisms and value of the priming principle. DESIGN: Double-blind, randomized, controlled trial. SETTING: Inpatient anesthesia in a university teaching hospital. PATIENTS: 90 ASA physical status I and II patients undergoing elective surgery requiring endotracheal intubation. INTERVENTIONS: Three groups of 30 patients each were investigated. Following induction of anesthesia with fentanyl and propofol, Group 1 received cisatracurium 0.015 mg.k(-1), Group 2 received rocuronium 0.09 mg. kg(-1), and Group 3 (control) received normal saline. Six minutes after priming, Groups 1 and 2 received cisatracurium 0.135 mg. kg(-1) whereas Group 3 received cisatracurium 0.15 mg. kg(-1). MEASUREMENTS AND MAIN RESULTS: In each group, first twitch height and the train-of-four ratios were recorded every 10 seconds after the initial priming dose. Intubation was attempted after the first twitch height became less than 15% of baseline. The decrease in the train-of-four ratios at 6 minutes was 0.97 for cisatracurium and 0.85 for rocuronium. The onset of muscle relaxation was significantly faster after priming with cisatracurium and rocuronium (71.7 +/- 21.3 and 65 +/- 19.8 sec, respectively) compared with control (148.7 +/- 43.1 sec). Females receiving both muscle relaxants had a faster onset of paralysis than did males (65.9 +/- 20.6 vs. 79.2 +/- 20.6 and 55 +/- 14.5 vs. 71.7 +/- 20.4 sec). Intubation conditions were either excellent or satisfactory in all patients. CONCLUSIONS: Six minutes after precurarization, there is no significant difference between rocuronium and cisatracurium when used as priming drugs. An even faster onset time with both drugs was demonstrated in females. The use of priming doses of 25% to 30% of ED(95) may cause symptomatic muscle weakness. The mechanisms of the priming principle are discussed.

Postoperative sudden sensorineural hearing loss after posterior lumbar decompression: a case report.

PURPOSE: We report a case in which a patient sustained a dural tear during spinal surgery under general anesthesia complicated by a severe and persistent unilateral sensorineural hearing loss. CLINICAL FINDINGS: A 51-yr-old man with no previous otological history underwent a posterior lumbar decompression surgery in the prone position under general anesthesia. A small dural tear was discovered intra-operatively and was repaired by sutures. Surgery lasted for eight hours with over 3 L of blood loss. Recovery from anesthesia was otherwise uneventful. A unilateral right-sided sensorineural hearing loss was discovered shortly after completion of surgery. This was associated with mild tinnitus but no vertigo. There was no aural fullness, pain, headache or postural element to his symptoms. Despite extensive investigations, treatment and follow-up by an otorhinolaryngologist, his symptoms failed to improve 18 months following surgery. DISCUSSION: The possible etiologies, preventive strategies, prognosis and management plan of this rare complication are discussed.

Long-term therapy of chronic non-malignant pain with potent opioids in an active police officer.

PURPOSE: To report the successful long-term use of methadone and tramadol in treating low back pain in a marine police officer. PRINCIPAL FINDINGS: The patient sustained a work-related injury having fallen down stairs while on duty in 1990. After multiple operations for a prolapsed L5/S1 intervertebral disk, he was first seen at our pain clinic in 1994. Numerous systemic medications, invasive procedures, physiotherapy and psychotherapy were used to treat his pain, but without sustained effect. Methadone was started in late 1995 and tramadol in 2000. The current maintenance doses are methadone 20 mg and tramadol 200 mg, both twice daily. Apart from some initial disruption, the patient was soon able to return to full time work. Regular performance reports from his supervisors have always been excellent. CONCLUSION: The use of methadone in this police officer with chronic low back pain has been very successful despite the demanding nature of his job. The controversy surrounding, and further suggestions regarding long-term use of opioid therapy for non-malignant pain are discussed.