ABSTRACT
Objective To evaluate the effects of age factors on sedation induced by dexmedetomidine.Methods One hundred and thirty-nine patients,aged 18-103 yr,with body mass index ≤ 30 kg/m2,scheduled for elective surgeries on lower abdomen or lower extremities,were divided into4 groups according to the age:group Ⅰ (18 yr≤age≤44 yr,n=40);group Ⅱ (45 yr≤age≤59 yr,n=38);group Ⅲ (60 yr≤age≤89 yr,n=39);group Ⅳ (≥90 yr,n=22).A catheter was placed in the subarachnoid space at L3,4 interspace,and ropivacaine 10-20 mg was injected via the catheter.At 20 min after ropivacaine injection,dexmedetomidine 1 μg/kg was infused via a pump over 10 min.The onset time and duration of sedation were recorded,and the occurrence of adverse effects such as hypoxemia,bradycardia and hypotension was observed.Results There was no significant difference in the onset time of sedation and incidence of bradycardia among the 4 groups (P＞0.05).Compared with group Ⅰ,the duration of sedation was significantly prolonged in Ⅱ-Ⅳ groups (P＜0.05).Compared with Ⅱ and Ⅲ groups,the duration of sedation was significantly prolonged in group Ⅳ (P ＜ 0.05).The incidence of hypoxemia and hypotension was significantly higher in group Ⅳ than in Ⅰ-Ⅲ groups (P＜0.05).Conclusion Dexmedetomidine-induced sedation is influenced by age factors,the duration of sedation induced by dexmedetomidine is prolonged,and the occurrence of adverse effects is increased,especially if the patients ≥ 90 yr of age.
ABSTRACT
Objective To evaluate the influence of age factors on etomidate sedative potency.Methods One hundred and fifty (ASA physical status Ⅰ or Ⅱ) patients of both sexes,scheduled for elective operation under general anesthesia,were divided into 3 groups according to age (n =50 each):group Y 18-44 yr,group M 40-64 yr and group O 65-75 yr.Each group was randomly divided into 5 subgroups receiving in'venous etomidate 0.07,0.09,0.11,0.13 and 0.17 mg/kg,respectively.Loss of consciousness was evaluated depending on loss of eyelash reflex within 5 min after intravenous administration.Results ED50 of etomidate inducing loss of consciousness was 0.13,0.11 and 0.09 mg/kg in group Y,M and O,respectively.Compared with that in group Y,ED50 was significantly decreased in group O,however,and showed no significant change in group M.Conclusion Age factors can affect sedative potency of etomidate,which appears greater in the elderly patients.
ABSTRACT
Objective To study the effects of aged and exercise training on hydroxylysylpyridinoline (HP) crosslinking concentrations of extracellular matrix in right ventricular (RV),left ventricular septum (LVS) and left ventricular free-wall (LVFW) in Fischer 344 rats.Methods We evaluated HP crosslinking concentrations of RV,LVS and LVFW extracellular matrix in young adult versus old Fischer 344 rats using high-pressure liquid chromatography (HPLC).Rats were assigned to either a sedentary control group or an exercise training group.Results HP crosslinking concentrations in LVS [(0.23±0.01) vs.(0.43±0.03)mol HP/mol Col,P＜0.05] and LVFW [(0.22±0.05) vs.(0.51±0.03) mol HP/mol Col,P＜0.05] in old sedentary control rats were elevated compared with adult sedentary rats.In adult exercise training rats,training had no effect on HP crosslinking concentration in any of the three regions of the heart.As compared with old sedentary rats,HP crosslinking concentrations in LVS [(0.22±0.06) mol HP/mol Col vs.(0.43±0.03)mol HP/mol Col,P＜0.05] and LVFW[(0.21±0.07)mol HP/mol Col vs.(0.51±0.03) mol HP/mol Col,P＜0.05] were decreased in old exercise training rats.Conclusions HP crosslinking concentration are increased with aging in LVS and LVFW of rats,and exercise can prevente this age associated change.