Comparative study of triiodothyronine and thyroxine in blood serum on rocuronium- induced neuromuscular block when combined with sevoflurane anesthesia

Objective To observe the effect of triiodothyronine and thyroxine in blood serum on rocuronium- induced neuromuscular block when combined with sevoflurane anesthesia. Methods Forty female patients,scheduled for thyroid surgery,of American Society of Anesthesiology(ASA) physical statusⅠorⅡ, were divided into two groups(n= 20 each):hyperthyroidism group(group N)and the normal thyroid function group(group C),according to the T3 and T4 levels.After anesthesia was induced,a bolus of rocuronium 0.6 mg/kg was given.Anesthesia was maintained with inhalation of sevoflurane and infusion of remifentanil. Then neuromuscular function was monitored using train- of- four stimulation(TOF)response measured by accelemgraphy.The onset time, no response time, clinical duration, recovery index, response in vivo time, the time of TOF recovery to 70% and 90% were recorded. Results As compared with group C, onset time [(87±22)s vs.(108±39)s], T1 no reaction time[(5.8±2.8)min vs.(22.8±6.1)min], the clinical duration[(17.3±2.3)min vs.(34.1±7.4)min], recovery index[(8.3±2.1) min vs.(14.8±4.1) min],in vivo time[(32.0±2.6)min vs.(49.6±7.7)min],the time of TOF recovered to 70%[(36.4±5.6)min vs. (57.8±7.6)min]and to 90%[(42.3±8.4)min vs.(63.3±8.5)min]in group N were significantly shortened,P<0.05 for all. Conclusion For patients with high T3 and T4 levels having a shorter onset time of rocuronium, we can intubate in a relatively short time.Hyperthyroidism can shorten the duration of action of rocuronium when combined with sevoflurane anesthesia,and the strength of muscle can restore faster in these patients. Key words: Hyperthyroidism; Rocuronium; Neuromuscular blockade