[The effects of age on onset and recovery from atracurium, rocuronium and vecuronium blockade]. / Die Wirkung des Alters auf Anschlagszeit und Erholung nach Atracurium, Rocuronium und Vecuronium.

UNLABELLED: Elderly patients may show an age-related decline in physiologic functions, which may be responsible for the prolonged duration of some neuromuscular blocking agents. Previous studies have yielded conflicting results as to the effects of these drugs in the elderly. METHODS: After obtaining informed consent and approval of the Ethics Committee, we compared onset and recovery times of single IV doses of atracurium, rocuronium, and vecuronium given to 108 patients divided into three groups according to age (18-50, 51-64, > or = 65 years). Following oxazepam premedication and fentanyl and thiopentone induction, patients were randomly allocated to receive atracurium, rocuronium or vecuronium (0.5, 0.6, or 0.1 mg/kg, respectively) in < or = 0.8 vol.% enflurane (end-tidal)-nitrous oxide anaesthesia. Muscular relaxation was assessed by electromyographic (EMG) recording of the adductor pollicis muscle after supramaximal single-twitch stimulation of the ulnar nerve every 10 s. Onset time and recovery to 25%, 75% and 90% of twitch control values (DUR25, 75, 90) were recorded. Creatinine clearance predicted from serum creatinine (Ccr) was correlated with recovery from neuromuscular block. RESULTS: Onset time was not different among groups or relaxants. The results showed a prolonged duration of action for atracurium (DUR75, DUR90), rocuronium (DUR25, DUR75), and vecuronium (DUR25) in the elderly. A number of patients did not reach DUR75 or DUR90. There was a significant relationship between age and failure to return to control values during recovery from neuromuscular block, especially after atracurium and rocuronium. Ccr showed a negative correlation with age for all relaxants, but a negative significant correlation between Ccr and recovery was found only for rocuronium. CONCLUSIONS: This study suggests that onset time for atracurium, rocuronium and vecuronium is not age-dependent. Recovery was prolonged in the elderly for all three relaxants. This effect appears to be secondary to changes in body composition and function accompanying the aging process. Neither atracurium nor vecuronium depends significantly on the kidney for elimination, but the negative correlation between Ccr and rocuronium suggests an appreciable role for the kidney in the elimination of this relaxant. The long recovery times observed in this study could also be related to enflurane anaesthesia. We suggest that failure of EMG responses to return to baseline values during recovery from neuromuscular block may be related to age, especially for atracurium and rocuronium.

Clinical investigation of potency and onset of different lidocaine sprays for topical anesthesia in dentistry.

The clinical effects of three lidocaine-containing solutions with and without frigen (freon-113) as a propellant, after different waiting periods, and with different dosages applied were investigated in 130 outpatients who were undergoing dental treatment in the maxilla under local anesthesia. They were divided randomly into five groups (A through E): (A) Xylocaine spray with frigen, two applications (20 mg lidocaine); (B) Xylestesin spray with frigen, two applications (14 mg lidocaine); (C) Xylestesin spray with frigen, three applications (21 mg lidocaine); (D) Xylestesin pump spray without frigen, two applications (14 mg lidocaine); and (E) no topical anesthesia. They were further divided into 12 subgroups to evaluate waiting periods between the application of the topical anesthesia and the injection (1, 2, or 3 minutes). Patients assessed the pain of the injection, intensity of numbness, and intensity of the taste on a visual analog scale; they also assessed the pain of the injection compared to former injections. Pain during injection was reduced by topical application of lidocaine. A waiting period of 2 minutes proved to be sufficient and can be justified to avoid impatience and increased numbness in patients. However, a 3-minute waiting period may be appropriate for sensitive patients. An increase in the dosage failed to show better analgesia. The pump spray without frigen proved to be effective.

The ultra-thin bronchoscope in management of the difficult paediatric airway.

The use of an ultra-thin flexible fiberoptic bronchoscope with a single lumen diameter of 2.7 mm at the distal tip to assist intubation of paediatric patients with a difficult airway is reported. Two patients (ages 30 months and 18 months) with mandibular hypoplasia and one patient (three months) with the Pierre-Robin syndrome are reported. In each case two fiberoptic bronchoscopes were used. The first allowed introduction of topical local anaesthetic while the second and smaller one was used for tube placement.