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Hello everyone,
Does anyone know how to interpret these readings? I have tried to understand the data from
the manual but was unable to guess what these mean. The drug given is fentanyl.
Thank you.
MA
9999 0
0.0000 0.1667 1296.483885
0.1667 3.6667 0.000000
3.6667 3.8333 2.722932
3.8333 8.0000 7.690301
8.0000 13.5000 7.299642
13.5000 20.8333 6.928389
20.8333 30.3333 6.579309
30.3333 39.9167 6.275026
39.9167 40.0833 1392.197651
40.0833 43.0833 0.000000
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The following message was posted to: PharmPK
Hi Rann
The explanation is in the Stanpump manual, I've copied the relevant paragraph below for you.
"STANPUMP also creates a file ending with the extension ".DRG". This file is a compressed
infusion function which we use when using nonlinear regression of computer controlled drug
delivery. The first line, "9999 0" specifies that no boluses were given (our regression
software will process either boluses or infusion, with boluses listed first). Subsequent
lines show a consecutive listing of infusions, starting with time on (min), time off
(min), and rate (units/min). The last infusion is 9999 9999 0, which is, again, a flag to
our nonlinear regression software that there are no more infusions to process."
With best wishes
Ann
-
Ann Rigby-Jones PhD MRSC
Research Fellow in Pharmacokinetics & Pharmacodynamics
Peninsula College of Medicine & Dentistry
N31, ITTC Phase 1
Tamar Science Park
1 Davy Road
Derriford
Plymouth
PL6 8BX
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Hi Ann,
For example let's look at this line:
39.9167 40.0833 1392.197651
I have manually written down what appears on STANPUMP during the infusion. What I got was
at 39 minutes and 36 seconds the total infused was (459 microgram, 3.8 microgram/kg, 9.19
mls) and pump rate were 7.38 mls/hr or 51.25 ngs/kg/min. So what does 1392.197 represent?
Thank you.
Regards,
MA
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The following message was posted to: PharmPK
Hi Rann
I presume you were running in TCI mode? What you see in the .drg file is the series of
mini infusions required (according to the PK model) to achieve the target concentration in
your patient. So the line
Time on (min) Time off (min) Pump rate (units/min)
39.9167 40.0833 1392.197651
is telling you that between 39.9167 and 40.0833 (0.1666 mins), the pump was running at a
rate of 1392.2 units/min. It looks like there was an increase in target concentration at
39.9 mins and then at 40.08 mins the target concentration was reduced (as the infusion
stopped at this point)?
All the best
Ann
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Rann, try calculating 3 more columns from your work sheet;
Col1=start
Col2=end
Col3= units/min
duration of that interval (col2-col1),
amt (col3*dur)
and cumulative amt
dur amt cum amt
0.1667 216.1238636 216.1238636
3.5 0 216.1238636
0.1666 0.453640471 216.5775041
4.1667 32.04317718 248.6206813
5.5 40.148031 288.7687123
7.3333 50.80795505 339.5766673
9.5 62.5034355 402.0801028
9.5834 60.13608417 462.216187 *****
0.1666 231.9401287 694.1563157
3 0 694.1563157
At 39 minutes and 36 seconds when you recorded the total infused was 459 microgram, then
you were actually within the period marked with the asterisks, so the total amt delivered
matched up nicely and confirms col3 is units/min in this case micrograms/min.
Best regards,
Simon.
--
Simon.Davis.aaa.certara.com
Senior Scientific Consultant
Pharsight- A Certara(tm) Company
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