Download CVL Draw

A Study Comparing Factor Level
and Inhibitor Titer Testing
Results Drawn from Central
Venous lines and Venipuncture
Judy Kauffman, RN, CPNP
Andrew Wilson, RN, CPHON
Kansas City Regional Hemophilia
Center
The Problem
• Many opinions about whether accurate
factor levels/ inhibitor titers can be
obtained from CVLs
• Children with poor venous access
hospitalized after venipuncture?
• The big issue: parents not willing to
participate in research due to requirement
for peripheral lab draws
Literature Review
• Multiple studies comparing CVL vs.
venipuncture for drug levels (MTX, abx)
– Most show that technique used to draw the
CVL specimen determines accuracy
Comparison of Coagulation
Testing
• McLaren, et al (2000) & Humphries and
Baldwin (2009) showed that PT, aPTT,
fibrinogen can be accurately drawn from
CVL
• Hinds, et al (2002) concluded that PT,
aPTT drawn from CVL were not accurate
• Lindley, et al (1994) compared FVII levels
drawn from CVL with venipuncture and
said that they could be compared
• Manco-Johnson, et all (2000) provided the
protocol for the study
– Method determines results
– CVL should be flushed w/ 10 ccs NS, then
10ccs of blood wasted before specimen is
drawn
– All CVL specimens should be treated with
heparinase
– With this method inhibitor titers drawn from
CVLs are accurate
Maximum Blood Draw Volumes for Pediatric
Patients
Body Wt. Kg
Body Wt. lbs
Max Volume (ml)
1
2.2
2.5
5
11
10
10
22
20
21-25
45-55
42-50
• Policy is 2.5% total blood volume, can be
increased with MD approval.
Adapted from Children’s Hospital and Regional
Medical Center Lab, Seattle, WA. 2001.
Preliminary Results
Subject
Veni Fac
Veni Inh
CVL Fac
CVL Inh
#1
FVIII 1%
0.09 BU
FVIII 1%
0 BU
#2
FVIII <1%
#3
FVIII 1%
0 BU
FVIII 1%
0 BU
#4
FVIII 7%
0BU
FVIII 7%
0 BU
#5
FVIII <1%
47.2 BU
FVIII <1%
47 BU
#6
FVIII 62%
0 BU
FVIII 48%
0 BU
#7
FIX 7%
0 BU
FIX 5%
0 BU
FVIII <1%
Veni Inh CVL Fac
Outlier
Subject
Veni Fac
#6
FVIII 62% 0 BU
• Peripheral Draw
– 1:10= 48%
– 1:20= 62%
– Low 1:10= 59%
CVL Inh
FVIII 48% 0 BU
• CVL Draw
– 1:10= 47%
– 1:20= 48%
– Low 1:10= 54%
Goal of Study
• To show whether factor levels and inhibitor
titers can be accurately drawn from CVLs
• Will need to expand this pilot study to
enroll enough subjects to achieve
significance
• Might be a good multi-center study?