Hostname: page-component-77c89778f8-m42fx Total loading time: 0 Render date: 2024-07-17T12:50:20.787Z Has data issue: false hasContentIssue false
  • English
  • Français

Can we rely on arterial line sampling in performing activated plasma thromboplastin time after cardiac surgery?

Published online by Cambridge University Press:  23 December 2004

A. Alzetani ,
H. A. Vohra  and
R. L. Patel
A. Alzetani
Affiliation:
University Hospitals Coventry and Warwickshire NHS Trust, Department of Cardiothoracic Surgery, Walsgrave Hospital, Coventry, UK
H. A. Vohra
Affiliation:
University Hospitals Coventry and Warwickshire NHS Trust, Department of Cardiothoracic Surgery, Walsgrave Hospital, Coventry, UK Present post: Clinical Research Fellow, Cardiac Surgery, University Hospitals Leicester NHS Trust, Glenfield Hospital, Leicester, UK.
R. L. Patel
Affiliation:
University Hospitals Coventry and Warwickshire NHS Trust, Department of Cardiothoracic Surgery, Walsgrave Hospital, Coventry, UK
Get access

Abstract

Summary

Background and objective: Arterial catheters are routinely used to sample blood for clotting studies in most cardiothoracic intensive care units. The clotting profile in surgical bleeding after cardiac surgery influences further management. Aspiration and discard of a certain amount of blood from the line, prior to sampling, are assumed to clear heparin contamination. We have investigated this assumption through analysis of the clotting profile by simultaneous arterial line and peripheral venous samples.

Methods: The morning following cardiac surgery, simultaneous arterial line and peripheral venous blood samples were taken for activated plasma thromboplastin time (APTT) ratio and international normalized ratio (INR) in 49 randomly selected patients. Also, a thromboelastogram analysis (TEG) (n = 7) was made. A survey of 22 UK cardiothoracic intensive care units was carried out to determine the practice for the withdrawal of blood for clotting studies.

Results: The median arterial APTT ratio value was 1.32 ± 0.52 as compared to the median peripheral APTT ratio value which was 1.1 ± 0.24 (P < 0.001). INR values were statistically similar by both routes. Heparin contamination was confirmed by TEG which revealed that the R-value for arterial catheter blood samples without heparinase in the cup was higher (406.00 ± 64.44 s) compared with the value for arterial samples with heparinase in the cup (318.28 ± 47.26 s, P < 0.05). The survey of 22 UK cardiothoracic intensive care units showed that heparinized arterial lines were by far the commonest ports used for blood withdrawal for the measurement of APTT ratio results.

Conclusions: Samples withdrawn from heparinized arterial lines cannot be relied upon for APTT ratio results.

Keywords

BLOOD COAGULATION TESTS, partial thromboplastin timeTHROMBOELASTOGRAPHYCATHETERS, INDWELLING, arterial
Type
Original Article
Information
European Journal of Anaesthesiology , Volume 21 , Issue 5 , May 2004 , pp. 384 - 388
Copyright
2004 European Society of Anaesthesiology

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Heap MJ, Ridley SA, Hodson K, Martos FJ. Are coagulation studies on blood sampled from arterial lines valid? Anaesthesia 1997; 52: 640–645.Google Scholar
Konopad E, Grace M, Johnston R, Noseworthy T, Shustack A. Comparison of PT and APTT values drawn by venepuncture and arterial lines using three discard volumes. Am J Crit Care 1992; 1: 94–101.Google Scholar
Lew JKL, Hutchinson R, Lin ES. Intra-arterial blood sampling for clotting studies. Anaesthesia 1991; 46: 719–721.Google Scholar
Templin KSM. Accuracy of drawing coagulation samples from heparinised arterial lines. Am J Crit Care 1993; 2: 88–95.Google Scholar
Laxson CJ, Titler MG. Drawing coagulation studies from arterial lines: an integrative literature review. Am J Crit Care 1994; 3: 16–22.
Branson PK, McCoy MR, Phillips BA, Clifton GD. Efficiency of 1.4 percent sodium citrate in maintaining arterial line catheter patency in patients in a medical ICU. Chest 1993; 103: 882–885.Google Scholar
Gamby A, Bennett J. A feasibility study of non-heparinised 0.9% sodium chloride for transduced arterial and venous lines. Intens Crit Care Nurs 1995; 11: 148–150.Google Scholar
Kulkarni M, Elsner C, Ouellet RN, Zeldin R. Heparinised saline versus normal saline in maintaining patency of radial artery catheter. Can J Surg 1994; 37: 37–42.Google Scholar