IntroductionContinuous heparin infusions

require monitoring of aPTT values and appropriate adjustments in the

infusion rate.

If the heparin is infusing through the central venous access devices (CVAD), how should aPTTs

be collected? Peripheral required/desired? From CVAD acceptable?

Turn off infusion?Flush first?Waste amount?Desired port?

For patients with central venous access devices (CVAD), blood samples may be collected from the CVAD or from a peripheral vein.

Comparison of aPTT values from venipuncture and central venous access device specimens in hospitalized adult patients receiving

continuous heparin infusionsMary Sue Dailey, APN- CNS, Fortunata Dabu, RN, BSN, Sue Durkin, APN- CNS, Barbara Gulczynski, APN- CNS, NP,

Colleen O’Leary, APN-CNS, Carrie Bauman, RN, BSN, Karen Calimlim, RN, BSN, Karen Hagemaster, RN, BSN, Joy Kennedy, RN, BSN, Barbara Kohn, MTRN, BSN,

Comparison of aPTT values from venipuncture and central venous access device specimens in hospitalized adult patients receiving

continuous heparin infusionsMary Sue Dailey, APN- CNS, Fortunata Dabu, RN, BSN, Sue Durkin, APN- CNS, Barbara Gulczynski, APN- CNS, NP,

Colleen O’Leary, APN-CNS, Carrie Bauman, RN, BSN, Karen Calimlim, RN, BSN, Karen Hagemaster, RN, BSN, Joy Kennedy, RN, BSN, Barbara Kohn, MTRN, BSN,

Selected References

Preliminary ResultsPaired blood specimen results compared

62% of specimens correlate within 10%

Further data analysis concerning type of line, concurrent infusions, and other clinical variables will be performed

Previous StudiesVenipuncture vs Peripheral VAD•Powers (1999) n=32•Prue-Owens (2006) n=23

Venipuncture vs Arterial Line•Alzetani (2004) n=49•Heap (1997) n=79

Venipuncture vs CVAD•Bellmunt. P, et al. (2000) n=74•Humphries and Baldwin (2009) n=30

.

Discrepancies

PoliciesLab•Turn off infusion•Waste depends on dead spaces : 5-12mL•Coags first

Nursing•Does not mention stopping infusion first•No mention of “desired port”•Waste first 6 mL•No guidelines regarding order of tube fillProfessional

StandardsInfusion Nursing Society (2006)•Stop infusion•Flush with 3-5 mL•Distal lumen preferred•Discard volume equal to 1.5-2 times the fill volume of the CVAD

Manufacturer’s Guidelines Arrow (TLC)

Use proximal port Turn off distal infusions for at least

one minuteDiscard volume varies from priming

volume (dead space) to 3-10mL

Bard (PICC)Flush per hospital protocolWaste 2-6 X the priming volume 5mL = 6x the priming volume of all non-

tunneled PICC

Study DesignPaired blood samples from 80 patients receiving a continuous heparin infusion through a CVAD will be collected by a research RN and a lab phlebotomist•CVAD specimen•Peripheral Venous specimen•Need 74 subjects (37 in each group) to detect a 2 second difference between specimens (SD 3 seconds) Power of .80 and alpha=.05

Clinical environment and demographic data collected

Further Data AnalysisComparison of paired blood specimen results, screening for outliers, and unexpected variations

Further review of Clinical Environment and Demographic data to be done, including analysis of trends per individual research RN

Following data verification, descriptive statistics

will be generated

Obstacles and Solutions

Actual RN practice 134 respondents completed

online survey•82% flush prior to obtaining sample•50% waste 10 mL•56% collected coag specimen first•94% stop infusion

Range of % Difference of Lab Draw aPTT and RN aPTT

Purpose of StudyIs there a clinically significant difference between

the aPTT results from a specimen collected fromCVAD and a specimen collected from a peripheralvein? Patient Consent- Many critically ill

Patient/ Family reluctant/unwilling to be “stuck”Concurrent focus on central line

necessityReports generated early AM- patient

condition changes Research RN coverage

• Bellmunt. P., et al. (2000). Sample extraction through central venous catheters to control partial thromboplastin time in patients undergoing heparin sodium perfusion. Enfermeria Intensiva 11(4), 155-60.

• Humphries, L., & Baldwin, K. (2009). A study comparing test results from PICCs and veinipunctures. Poster presentation at National Association of Clinical Nurse Specialists Annual Conference.