Influence of Anesthesia Drugs on Impedance Aggregometry

Platelet Dysfunction Clinical Trial

Official title:

The Influence of Drugs Routinely Used in Cardiac Anesthesia on Impedance Aggregometry.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01454427
• Other study ID #: 122/10
• Status: Completed
• Phase: N/A
• First received: October 18, 2011
• Last updated: October 18, 2011
• Start date: October 2010
• Est. completion date: May 2011

Study information

• Verified date: October 2011
• Source: University of Lausanne Hospitals
• Contact: n/a
• Is FDA regulated: No
• Health authority: Switzerland: Federal Office of Public Health
• Study type: Observational

Clinical Trial Summary

Impedance aggregometry (IA) (Multiplate®)is a new whole blood platelet function test with potential use in anesthesia and intensive care. Most anesthetic drugs have been shown to have in vitro antiplatelet activity. The goal of this in vitro study is to evaluate the effect of several drugs, frequently used in cardiac anesthesia and intensive care, on platelet function as measured by IA

Description:

Impedance aggregometry (IA) on the multiple platelet function analyzer (Multiplate®) ) is a whole blood point of care test evaluating platelet function. In IA, the increase in electrical impedance of whole blood is measured after the addition of a platelet activator. Some of the activators available are arachidonic acid (ASPI Test), ADP (ADP Test), TRAP-6 (TRAP Test) and collagen (COL TEST).

When an activator is added to the blood sample, the activated platelets will aggregate on the electrodes embedded in the test recipient. As platelets accumulate on the electrodes surface, the impedance will increase. The increase is measured and expressed in arbitrary units (AU). Reduced impedance implies platelet dysfunction or the presence of specific platelet inhibitors. For example, the ASPI test is inhibited in the presence of acetylsalicylic Acid and clopidrel inhibits the ADP test. Thrombin (TRAP) is an extremely potent agonist which can be used to monitor GpIIb/IIIa therapy.

The Multiplate® analyzer may have an important role in detecting and analyzing perioperative coagulopathies, but many drugs, routinely used in cardiac anesthesia or in the intensive care unit, have known in vitro antiplatelet effects, and may interfere with IA interpretation.

The goal of the study is to evaluate the influence of lidocaine, propofol, midazolam, and magnesium on the results of impedance aggregometry and to understand to which extent the tests are modified by the presence of one of these drugs.

20 healthy volunteers aged 18 to 65 years old will be recruited. Exclusion criteria are the use of non-steroidal anti-inflammatory drugs for 2 weeks prior to donation and known coagulation disorders. Whole blood is taken from the antecubital vein. Platelet count is measured. Blood samples for Multiplate® analysis are drawn in hirudin anticoagulated tubes. During storage, blood is gently moved in order to avoid sedimentation and spontaneous platelet aggregation.

For each sample baseline measurements are performed using ASPI Test, ADP Test, TRAP Test and COL Test.

The four study drugs are added to the blood samples, in isovolumic dilutions, to obtain subclinical, normal or near toxic plasma concentrations (table 1).

Study drugs low intermediate high Lidocaine (mcg/ml) 1 3 6 Magesium (mMol/l) 0.4 1 2.5 Midazolam (ng/ml) 150 250 500 Propofol (mcg/ml) 2 5 8 Table 1. Plasma concentration of the four study drugs

For every concentration, IA is measured using the 4 different activators. For every test and dose, the area under the curve is compared with the baseline.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 20
• Est. completion date: May 2011
• Est. primary completion date: May 2011
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 65 Years

Eligibility

Inclusion Criteria:

• Age 18 to 65 years old

Exclusion Criteria:

• Use of non-steroidal anti-inflammatory drugs for 2 weeks prior to donation.

• Known coagulation disorders.

Study Design

Observational Model: Cohort, Time Perspective: Prospective

Related Conditions & MeSH terms

• Blood Platelet Disorders
• Platelet Dysfunction

Locations

Country	Name	City	State
Switzerland	University of Lausanne Hospitals	Lausanne	Vaud

Sponsors (1)

Lead Sponsor	Collaborator
University of Lausanne Hospitals

Country where clinical trial is conducted

Switzerland, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Drug induced platelet dysfunction as measured by impedance aggregometry.