Chapter 4: Heparin Management in Cardiopulmonary Bypass Surgery 4-5
It is important to note that protamine itself can have an anticoagulant effect if too much protamine has
been administered or if the blood sample is tested before enough time has passed for the protamine to
fully neutralize the heparin.
Platelet Function
The Sonoclot Signature Clot Retraction Phase is the period when clot retraction is occurring within the
test sample. This phase is influenced by activated platelets retracting the clot. This point can be illustrated
by looking at Sonoclot Signatures that have platelets inhibited by anti-platelet drugs.
The result of reducing platelet function by inhibiting platelets attenuates and finally eliminates clot
retraction. The Sonoclot Signatures get flatter and flatter after the fibrin clot forms. Note that the effect
of inhibiting platelets does not affect either the Coagulation Reaction Phase (ACT) or the Clot Formation
Phase (Clot Rate). The Platelet Function result is specific to clot retraction and fibrin clots can form without
any clot retraction. Low platelet function results provide a useful indicator to help guide platelet blood
component therapy. Important: useful platelet function results require that a fibrin clot forms. Heparin,
inadequate coagulation factors, or low fibrinogen can all contribute to impaired clot retraction. In order
to properly identify poor platelet function, first ensure that the Sonoclot Signature or ACT and Clot Rate
results are sufficient to form a fibrin clot. If either the ACT or Clot Rate results indicate an inability to
form a fibrin clot, this coagulopathy needs to be corrected prior to using the Platelet Function result as
an indicator of poor platelet function.
Integrilin
Minutes
0.0
5.0
10.0
15.0
20.0
25.0
30.0
Clot
Signal
0
25
50
75
100
125
Group Description
Style Time Test Application Result Range Comment
1
2
3
4
5
Increasing Reagent: 1 to 5
Integrilin 2
Minutes
0.0
5.0
10.0
15.0
20.0
25.0
30.0
Clot
Signal
0
25
50
75
100
125
Group Description
Style Time Test Application Result Range Comment
1
2 3
4
5
Increasing Reagent: 1 to 5
Integrilin
Integrilin
Aggrastat
Minutes
0.0
5.0
10.0
15.0
20.0
25.0
30.0
Clot
Signal
0
25
50
75
100
125
Group Description
Style Time Test Application Result Range Comment
Aggrastat
Increasing Reagent: 0, 1, ...
0
1
2
3
4
