Gambro Cobe Spectra, Essentials Manual

Page: 106 / 245

Anticoagulation
8-4 COBE
®
Spectra™ Apheresis System • Essentials Guide
Any changes made to the inlet pump flow rate affect the AC pump flow
rate (proportionately) and the AC infusion rate. By increasing the inlet
pump flow rate, you can increase the AC infusion rate up to
1.2 mL/min/L of TBV for all procedures except RBCX procedures, and
up to 1.4 mL/min/L of TBV for RBCX procedures.
If you increase the inlet pump flow rate so that the AC infusion rate
exceeds 1.2 (or 1.4) mL/min/L of TBV, the “AC infusion rate exceeds
allowable limits” alarm occurs. The inlet pump slows to maintain an AC
infustion rate of 1.2 mL/min/L of TBV.
To accommodate certain medical situations during TPE procedures,
such as infusion of calcium, you can continue the Run mode in a yellow
warning state at an AC infusion rate greater than 1.2 mL/min/L of TBV.
See the “AC infusion rate exceeds (allowable) limit(s).” alarm on
page 12-9 for details.
The system calculates the volume of AC included in the collected
products or plasma, and uses this information to determine the
appropriate AC pump flow rate. You may view the volume of removed
AC at any time during the procedure (see “AC Data” on page 5-10 for
more information).
Configuring the Inlet:AC Ratio
Each apheresis procedure has a default inlet:AC ratio, but you can
configure this ratio (see “Configuring the Inlet:AC Ratio” on page 5-5).
As you increase the inlet:AC ratio during a procedure, the following
occur:
•
AC pump flow rate remains unchanged (to maintain the
AC infusion rate)
•
Inlet pump flow rate increases, adding more donor/patient blood to
a given amount of AC
•
Anticoagulation of the system decreases
Under most circumstances, changing the inlet:AC ratio during the
procedure only changes the inlet pump flow rate. The AC pump flow
rate remains the same. Under certain circumstances, however, the
Spectra system changes the AC pump flow rate to maintain a constant
AC infusion rate. If the inlet pump flow rate (65 mL/min for Single-
Needle ELP and LRS procedures, 70 mL/min for Single-Needle LRST
procedures) is maximized, and the inlet:AC ratio is increased, the AC
pump flow rate decreases to maintain the configured inlet:AC ratio.
Consider the donor/patient’s platelet count and Hct before changing the
inlet:AC ratio. You may use ratios up to 15:1 if the platelet count and
Hct are low. If the donor/patient platelet count and Hct are high, you
may need to use a a ratio lower than the default.
Note: The Nadler and Allen formula (shown here in metric and
English units) for total blood volume is as follows:
Females: 183 + [356 x Height
3
(meters)] + [33.1x weight (kg)] =
TBV in mL
Males: 604 + [367 x Height
3
(meters)] + [32.2 x weight (kg)] =
TBV in mL
Females: 183 + [0.005835 x Height
3
(inches)] + [15 x weight
(lbs)] = TBV in mL
Males: 604 + [0.006012 x Height
3
(inches)] + [14.6 x weight
(lbs)] = TBV in mL
References:
1 Nadler SB, et al. Prediction of blood volume in normal human
adults.
Surgery 1962;51:224.
2 Allen TH, et al. Prediction of blood volume and adiposity in
man from body weight and cube of height. Metabolism
1959;39:307.