Nur Baykara1, Mine Solak, Kamil Toker. 1. Department of Anesthesiology, School of Medicine, University of Kocaeli, Kocaeli, Turkey. baykaranur@yahoo.com
Abstract
STUDY OBJECTIVE: To determine the influence of aging on the relationship between posttetanic count (PTC) and train-of-four (TOF) response during intense neuromuscular blockade caused by rocuronium. DESIGN: Prospective, observational, clinical comparison study. SETTING: Operating room of a university hospital. PATIENTS: 42 ASA physical status I and II patients, 20 of whom were elderly (ages 65 to 80 yrs) and 22 younger control patients (ages 18 to 40 yrs), who were scheduled for elective orthopedic surgery and ear, nose, and throat surgery with a planned duration of 2 hours. INTERVENTIONS: Neuromuscular blockade was evaluated with accelerometry of the thumb, using posttetanic twitch (PTT) and TOF stimulation of the ulnar nerve, in patients who received rocuronium 1 mg x kg(-1). MEASUREMENTS AND MAIN RESULTS: The first responses to posttetanic nerve stimulation were seen at mean times of 38.5 and 35.2 minutes after the injection of rocuronium in the elderly and in the young, respectively (NS). The average interval between the appearance of a posttetanic response and the first response to TOF stimulation (T1) was longer in the elderly than the young (22.3 +/- 8.1 (SD) vs.14.8 +/- 4.2 min, p < 0.05). There was a significant correlation between PTC and the time to first response to TOF nerve stimulation both in the elderly and in the young (r = -0.73, p < 0.0001 and r = -0.87, p < 0.0001, respectively). CONCLUSIONS: Posttetanic twitch stimulation is a useful method of monitoring intense neuromuscular blockade caused by rocuronium in both age groups. The interval between the earliest appearance of a posttetanic response and the first response to TOF stimulation (T1) is greater in the elderly than in the young.
STUDY OBJECTIVE: To determine the influence of aging on the relationship between posttetanic count (PTC) and train-of-four (TOF) response during intense neuromuscular blockade caused by rocuronium. DESIGN: Prospective, observational, clinical comparison study. SETTING: Operating room of a university hospital. PATIENTS: 42 ASA physical status I and II patients, 20 of whom were elderly (ages 65 to 80 yrs) and 22 younger control patients (ages 18 to 40 yrs), who were scheduled for elective orthopedic surgery and ear, nose, and throat surgery with a planned duration of 2 hours. INTERVENTIONS: Neuromuscular blockade was evaluated with accelerometry of the thumb, using posttetanic twitch (PTT) and TOF stimulation of the ulnar nerve, in patients who received rocuronium 1 mg x kg(-1). MEASUREMENTS AND MAIN RESULTS: The first responses to posttetanic nerve stimulation were seen at mean times of 38.5 and 35.2 minutes after the injection of rocuronium in the elderly and in the young, respectively (NS). The average interval between the appearance of a posttetanic response and the first response to TOF stimulation (T1) was longer in the elderly than the young (22.3 +/- 8.1 (SD) vs.14.8 +/- 4.2 min, p < 0.05). There was a significant correlation between PTC and the time to first response to TOF nerve stimulation both in the elderly and in the young (r = -0.73, p < 0.0001 and r = -0.87, p < 0.0001, respectively). CONCLUSIONS:Posttetanic twitch stimulation is a useful method of monitoring intense neuromuscular blockade caused by rocuronium in both age groups. The interval between the earliest appearance of a posttetanic response and the first response to TOF stimulation (T1) is greater in the elderly than in the young.