| Project/Area Number |
09671553
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Yamanashi Medical University |
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Principal Investigator |
MATSUKAWA Takashi Yamanashi Medical University, Department of Anesthesia, Associate Professor, 医学部, 助教授 (80209519)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAZAWA Teruo Yamanashi Medical University, Department of Anesthesia, Professor and Chairman, 医学部, 教授 (10092404)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1997: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | temperature / core temperature / peripheral temperature / vasoconstriction / premedication / general anesthesia / the elderly / age / 前投薬 / 降圧薬 |
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| Research Abstract |
Introduction : Thermoregulatory control is impaired in the elderly without anesthesia. Furthermore, the vasoconstriction and shivering thresholds are reduced more in elderly than young surgical patients. As might be expected from these observations, the elderly are most susceptible to perioperative hypothermia, and may also be a greater risk of hypothermia-induced complications. We recently demonstrated that midazolam pre-medication causes hypothermia. It is likely that thermal effects of midazolam are exaggerated in the elderly. Accordingly, we tested the hypothesis that hypothermia would be aggravated in the elderly after midazolam premedication and during general anesthesia.
Methods : With IRB approval and informed consent, we studied 15 patients aged 20-50 yr and 15 patients aged 65-80 yr. All were ASA physical status I-II and scheduled to undergo open abdominal surgery lasting more than 3 hours. The patients were premedicated with IM midazolam 0.05 mg/kg 40 min before induction of
… More
anesthesia. General anesthesia was then induced with propofol (1.5 mg/kg) and vecuronium. Anesthesia was maintained with nitrous oxide 67% and isoflurane at an end-tidal concentration of 1-1.5%.
Results : End-tidal isoflurane concentrations averaged 1.3*0.3% in the young patients and 1.2*0.2% in the elderly ones. Tympanic membrane temperature (Ttym) 30 and 40 min after midazolam premedication was significantly lower in the elderly than young patients. Subsequently, Ttym decreased significantly more in elderly than in young patients.
Conclusions : That midazolam 0.05 mg/kg caused minimal hypothermia in the young patients is consistent with our experience in volunteers in whom temperature decreased significantly only after 0.075 mg/kg. It is notable, however, that 0.05 mg/kg was caused significant hypothermia in the elderly. This indicates that kinetic or dynamic effects increased sensitivity in the older patients. The elderly patients subsequently became more hypothermic during surgery than the younger ones, as might be expected from previous reports. Our data suggest that the elderly may especially benefit from temperature monitoring and thermal management. Less
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