CareFusion Alaris PK Manual Del Usuario página 4

When targeting in TCI Mode the Alaris® PK Syringe 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 is intended to help users understand the profiled
infusion and the performance accuracy attained from the TCI pump.
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 Alaris® PK Syringe Pump updates the pharmacokinetic model driving the plasma (or effect) concentration prediction and the infusion
rate every 10 seconds. The infusion rate graph, shown on page 3, were measured in accordance with the protocol described in the
IEC60601-2-24 Standard, with the data sample period reduced from 30 to 10 seconds.
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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 pump 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 Alaris® PK Syringe 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 page 3, over a one hour
period, the Alaris® PK Syringe Pump has a mean volumetric accuracy in TCI Mode better than ±5%
By measuring the volume from the flow rate profile delivered from the Alaris® PK Syringe Pump and then introducing this into a reverse
pharmacokinetic model the predicted plasma (or effect) concentration can be calculated from the flow rate. These are illustrated on page 3,
showing the typical performance of the system against changes in the target plasma (or effect) concentration for a typical, idealised profile.
For the same targeted profile, the deviation of the predicted plasmatic (or effect) concentration (back calculated from the volume collected)
from the expected Ideal plasma (or effect) concentration, results from the volumetric inaccuracy of the system (pump and syringe). The
Alaris® PK Syringe Pump will track the predicted plasma (or effect) concentration to within ±5%
model over a one hour period. Flow rate inaccuracies and start-up delays may decrease the accuracy of the predicted plasma (or effect)
concentration particularly where high syringe drug concentrations are used in conjunction with large sizes of syringes and low target plasma
(or effect) concentrations as the syringe plunger motion over time (proportional to the flow rate accuracy) will be significantly reduced.
Note: For a given drug concentration, the volumetric error is proportional to the dose rate error. Knowledge of the system accuracy
over different time intervals may be of interest when assessing the impact of administering short-half life drugs. In these
circumstances, short-term fluctuation in the infusion rate could have a clinical impact that cannot be determined from
the performance profiles shown in Figures below. In general, the volumetric error will increase with small induction and
maintenance rates, which may occur with large volume syringes, high syringe concentrations, low patient weights and low
target (plasma or effect) concentrations. For applications where system accuracy is important, maintenance rates less than
1.0 ml/h are not recommended; syringe sizes, drug concentrations / dilutions and target (plasma or effect) concentrations
should be selected accordingly to ensure the maintenance rate exceeds this lower limit.
Note:
IEC60601-2-24: Particular Requirements for the Safety of Infusion Devices;
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95% Confidence / 95% Population.
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Profiles from TCI mode
1000DF00450 Issue 1 2/40
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of that calculated by pharmacokinetic
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