In:
Pharmacology, S. Karger AG, Vol. 69, No. 2 ( 2003), p. 102-107
Abstract:
We studied the effect of the inspired isoflurane concentration (C 〈 sub 〉 I 〈 /sub 〉 iso) on the pharmacokinetics of isoflurane uptake in the brain by comparing the isoflurane concentration in internal jugular-bulb blood (Jiso) with that in arterial blood (Aiso), and analyzed this by gas chromatography. Sixteen patients (aged 43–76 years) undergoing colorectal surgery were enrolled, and anesthesia was maintained with a constant C 〈 sub 〉 I 〈 /sub 〉 iso of either 1% (group 1, n = 8) or 2% (group 2, n = 8) during the 1st hour of isoflurane anesthesia. Under constant volume-controlled ventilation, we measured the C 〈 sub 〉 I 〈 /sub 〉 iso and the end-tidal isoflurane concentration (C 〈 sub 〉 E 〈 /sub 〉 iso) at the mouthpiece by infrared analysis. Our results demonstrate that it takes 40 min for the brain tissue concentration to equal Aiso for 1% C 〈 sub 〉 I 〈 /sub 〉 iso, and 50 min for 2% C 〈 sub 〉 I 〈 /sub 〉 iso. The Aiso (and/or Jiso) for 2% C 〈 sub 〉 I 〈 /sub 〉 iso was approximately double when compared to that for 1% C 〈 sub 〉 I 〈 /sub 〉 iso. Except during the initial wash-in period of the functional residual capacity in the first 3 min, the differences between C 〈 sub 〉 I 〈 /sub 〉 iso and C 〈 sub 〉 E 〈 /sub 〉 iso revealed that the body uptake of isoflurane for 2% C 〈 sub 〉 I 〈 /sub 〉 iso was twice that for 1% C 〈 sub 〉 I 〈 /sub 〉 iso. These results demonstrate that the pharmacokinetics of isoflurane uptake in the brain is time-dependent for Jiso to equal Aiso, and the midpoint between Aiso and Jiso (likely representing the isoflurane concentration in brain tissue) was dependent on C 〈 sub 〉 I 〈 /sub 〉 iso.
Type of Medium:
Online Resource
ISSN:
0031-7012
,
1423-0313
Language:
English
Publisher:
S. Karger AG
Publication Date:
2003
detail.hit.zdb_id:
1483550-2
SSG:
15,3
