Effects of pharmacodynamics of rocuronium in elderly patients / 中华麻醉学杂志

ABSTRACT

Objective To investigate the characteristics of pharmacodynamics of rocuronium in elderly patients. Methods Ninety-four ASA Ⅰ - Ⅱ patients aged between 32-97 yr were divided into 4 age groups groupⅠ 32-59 yr(n=28);group Ⅱ 60-69 yr (n = 29);group Ⅲ 70-89 yr (n=27);group Ⅳ 90-97 yr (n=10).The patients were premedieated with intramuscular phenobarbital 0.lg and atropine 0.5 mg. Anesthesia was induced with midazolam, propofol and fentanyl. Tracheal intubation was facilitated with rocuronium 0.6 mg?kg-1.The patients were mechanically ventilated and PET CO2 was maintained between 35-45 mm Hg. Anesthesia was maintained with isoflurane 1 MAC and intermittent iv boluses of fentanyl. Rocuronium was continuously infused during operation to maintain T1 at 10%-20% control.Neuromuscular (N-M) function was monitored using TOF response measured by accelerography.(1) Onset time (time from end of rocuronium injection to 100% block of T4 ),(2) maximal effect (time from end of injection to 100% block of T1 ),(3) clinical duration (time from end of injection to 10% recovery of T1 ) ,(4) intubating condition,(5) the amount of rocuronium consumed every 30 min and (6) recovery time (time from termination of rocuronium infusion to recovery of T1 to 25% control)Results (1) The onset time and the time of maximal effect were significantly longer in group Ⅰ than those in other three groups.(2) The time of maximal effect in group Ⅳ was significantly shorter than that in group Ⅱ and Ⅲ (3)The recovery time in group Ⅰ and Ⅱ was significantly shorter than that in group Ⅲ and Ⅳ.(4) The amount of rocuronium consumed per 30 min was decreasing with increasing duration of infusion and age. Conclusion The duration of action of rocuronium is longer and less amount of rocuronium is needed when it is given to elderly patients.