Remifentanil {nlme} | R Documentation |
Pharmacokinetics of Remifentanil
Description
Intravenous infusion of remifentanil (a strong analgesic) in different
rates over varying time periods was applied to a total of 65 patients.
Concentration measurements of remifentanil were taken along with several
covariates resulting in the Remifentanil
data frame with 2107 rows
and 12 columns.
Usage
data("Remifentanil", package = "nlme")
Format
This data frame (of class "groupedData"
, specifically
"nfnGroupedData"
) contains the following columns:
ID
:numerical (patient) IDs.
Subject
:an
ordered
factor with 65 levels (of theID
s):30
<21
<25
<23
<29
< ... ... <36
<6
<5
<10
<9
.Time
:time from beginning of infusion in minutes (
numeric
).conc
:remifentanil concentration in [ng / ml] (numeric).
Rate
:infusion rate in [µg / min].
Amt
:amount of remifentanil given in the current time interval in [µg].
Age
:age of the patient in years.
Sex
:gender of the patient, a
factor
with levelsFemale
andMale
.Ht
:height of the patient in cm.
Wt
:weight of the patient in kg.
BSA
:body surface area (DuBois and DuBois 1916):
% BSA := Wt^{0.425} \cdot Ht^{0.725} \cdot 0.007184
.LBM
:lean body mass (James 1976), with slightly different formula for men
LBM_m := 1.1 Wt - 128 (Wt/Ht)^2
, and womenLBM_f := 1.07 Wt - 148 (Wt/Ht)^2
.
Author(s)
of this help page: Niels Hagenbuch and Martin Maechler, SfS ETH Zurich.
Source
Pinheiro, J. C. and Bates, D. M. (2000). Mixed-Effects Models in S and S-PLUS, Springer, New York.
References
Minto CF, Schnider TW, Egan TD, Youngs E, Lemmens HJM, Gambus PL, Billard V, Hoke JF, Moore KHP, Hermann DJ, Muir KT, Mandema JW, Shafer SL (1997). Influence of age and gender on the pharmacokinetics and pharmacodynamics of remifentanil: I. Model development. Anesthesiology 86 1, 10–23. doi:10.1097/00000542-199701000-00004
Charles F. Minto, Thomas W. Schnider and Steven L. Shafer (1997). Pharmacokinetics and Pharmacodynamics of Remifentanil: II. Model Application. Anesthesiology 86 1, 24–33. doi:10.1097/00000542-199701000-00005
Examples
plot(Remifentanil, type = "l", lwd = 2) # shows the 65 patients' remi profiles
## The same on log-log scale (*more* sensible for modeling ?):
plot(Remifentanil, type = "l", lwd = 2, scales = list(log=TRUE))
str(Remifentanil)
summary(Remifentanil)
plot(xtabs(~Subject, Remifentanil))
summary(unclass(table(Remifentanil$Subject)))
## between 20 and 54 measurements per patient (median: 24; mean: 32.42)
## Only first measurement of each patient :
dim(Remi.1 <- Remifentanil[!duplicated(Remifentanil[,"ID"]),]) # 65 x 12
LBMfn <- function(Wt, Ht, Sex) ifelse(Sex == "Female",
1.07 * Wt - 148*(Wt/Ht)^2,
1.1 * Wt - 128*(Wt/Ht)^2)
with(Remi.1,
stopifnot(all.equal(BSA, Wt^{0.425} * Ht^{0.725} * 0.007184,
tolerance = 1.5e-5),
all.equal(LBM, LBMfn(Wt, Ht, Sex),
tolerance = 7e-7)
))
## Rate: typically 3 µg / kg body weight, but :
sunflowerplot(Rate ~ Wt, Remifentanil)
abline(0,3, lty=2, col=adjustcolor("black", 0.5))