Idiomas disponibles
Idiomas disponibles
Model Restrictions
Multiple covariates adjusted adult three compartmental PK model for Propofol enlarged with a simultaneously developed
effect compartmental model . Multiple covariates are defined as Age, Weight, Height, Gender and Lean Body Mass . The
Schnider model has a smaller central distribution volume than the Propofol Marsh model . Due to the inclusion of multiple
covariates, including age, successful use of this model for older patient populations than with Marsh, has been published .
Recommended infusate concentrations from publication are 10mg/ml or 20mg/ml .
As both kinetic and dynamic (effects site) parts were calculated simultaneously from the same population, this model
describes the time course of drug effect more accurately (Le Port et al .: Anesthesiology 2004, A491) . Le Port et al
confirmed in a heterogeneous surgical population that Propofol Plasma – Effect site equilibration is faster than predicted
by non modified Marsh and that the mean ke
drug effect versus effect site concentration .
Using the Schnider model, Struys et al found that 95% of the population lost consciousness at an effect site concentration
of 3 .8µg/ml when using Propofol alone, and 3 .1 – 2 .7µg/ml in combination with TCI Remifentanil (Minto model) 2ng/ml or
4ng/ml respectively (Struys et al .: Anesthesiology 2003, 99:802–12) .
Others have published similar dosing ranges .
In patients with compromised health, (ASA 3–4), targets should be titrated with care . It might be recommended to start
with a lower target and increase following onset of drug effect .
The information above is extracted from publications and we recommend the full reading and understanding of the
relevant publications on this model prior to use .
At the release of this document, no prescribing information is recommended for Propofol in administration mode using
the Schnider model . It is recommended that the 'Clinical Trial' option is set within the BD Alaris™ PK Editor Software until
prescribing information is available .
Effect site targeting will not trigger the Soft or Hard Limit alarms set for Plasma Concentrations .
Profiles from TCI Mode
When targeting in TCI Mode, the Pump will automatically calculate the flow rate profile from the specific pharmacokinetic/
pharmacodynamic model for the selected drug . This section of the Directions For Use Addendum is intended to help users
understand the profiled infusion and the performance accuracy attained from the pump in TCI Mode .
Induction Bolus and maintenance rates are displayed before starting the titration . When initially starting the infusion or
after increasing the target (plasma or effect) concentration by titration, the Pump will first deliver a bolus dose through a
typically short, high rate infusion . On completion of this bolus, the Pump will immediately switch to a lower maintenance
rate (when plasma target mode is used) or will pause for a period of time before switching to a lower maintenance rate
(when effect site targeting mode is used) . Once the maintenance phase is reached, any reduction made to the target
(plasma or effect) concentration will typically result in the infusion rate reducing to zero until the predicted plasma (or
effect) concentration reduces the new target value .
The Pump updates the pharmacokinetic model driving the plasma (or effect) concentration prediction and the infusion
rate every 10 seconds . The infusion rate graphs, shown on pages 5-6, were measured in accordance with the protocol
described in the IEC 60601-2-24
The Pump solves the pharmacokinetic/pharmacodynamic algorithms so that the target (plasma or effect) concentration is
attained as rapidly and as accurately as possible . However, the user may need to take into consideration the limitations of
the physical system in attaining the target (plasma or effect) concentration; this includes:
• The limit on the flow rate permitted by the infusion mechanism;
• The limit on the flow rate permitted by the syringe size;
• The patient / drug dose limitation from the prescribing information to insure the safety of the administration;
• The variation in individual patient response to reach the plasma (or effect) concentration;
• The model specific cap rate .
A true assessment of the performance of the Pump can be made if the volumetric error, that is the difference between the
actual volume infused and the predicted volume infused, is calculated . For the performance graphs shown on pages 5-6,
over a one hour period, the Pump has a mean volumetric accuracy in TCI Mode better than ±5%
value associated to the Schnider model better parallels the time course of
0
1
Standard, with the data sample period reduced from 30 to 10 seconds .
BDDF00869 Issue 1
Alaris™ PK/PK Plus Syringe Pump
Propofol-Schnider Model
2
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