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CC BY-NC-ND 4.0 · J Lab Physicians 2021; 13(02): 112-117
DOI: 10.1055/s-0041-1726669
Original Article

Performance of 3 mL versus 5 mL Discarded Volume for Blood Sampling from Central Venous Access Device

HT Lalthanthuami 
1   Department of Medical Surgical Nursing, College of Nursing, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India
,
MJ Kumari
2   College of Nursing, JIPMER, Puducherry, India
,
R Venkateswaran
3   Department of Medicine, JIPMER, Puducherry, India
,
PR Lakshmi
4   Department of Pharmacy, JIPMER, Puducherry, India
,
Lakshmi Ramamoorthy
2   College of Nursing, JIPMER, Puducherry, India
› Institutsangaben
Funding Sources Intramural fund received from JIPMER.
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Abstract

Background Central venous access devices (CVAD) are an essential part of safe practices in critical care, which enable effective venous access and help in avoiding repeated venipuncture. Discard method is widely practiced for blood sampling. A single occasion of blood sampling may cause minimal blood loss; however, the cumulative volume sequential sampling may become clinically significant. The study aims to reduce diagnostic blood loss, ensuring that the subsequent blood sample is not diluted or contaminated by residual intraluminal fluid.

Patients and Methods Within-subjects comparative design was adopted for 64 adult patients in the medical intensive care unit of a tertiary hospital. Two blood samples, using 3 mL and 5 mL discarded volume methods, were collected from each patient. Six serum parameters were measured on each of the paired samples and compared.

Statistical Analysis Used Paired t-test and Wilcoxon signed rank test were used for comparing the two methods. Bland–Altman plot analysis and intraclass correlation were used for clinically meaningful analysis.

Results When tested for fixed bias, there is no statistically significant difference between the methods. Potassium and creatinine levels showed significant proportional bias. The agreement limits of sodium, potassium, creatinine, and direct bilirubin were outside the clinically accepted interval, but the proportion of samples outside these intervals was less than 10%. All serum parameters showed excellent reliability, except for sodium which demonstrated good reliability.

Conclusions The practice of discarding 3 mL of blood for discard method is suggested, instead of the standard 5 mL to reduce iatrogenic blood loss. Thus, nurses in critical care are uniquely positioned to limit the diagnostic blood loss while obtaining blood samples.

Keywords

blood discards - discarded volume - blood sampling - critical care - central lines - central venous access device - diagnostic blood loss


Publikationsverlauf

Artikel online veröffentlicht:
17. Juni 2021

© 2021. The Indian Association of Laboratory Physicians. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).

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