Determination of the Minimum Discard Volume in the Extraction of Blood Samples Through Arterial Catheters in Critical Patients.
Patricia Morales Fernández, Francisco Javier Castro Olmo, Sara González-Martín and 5 others
PMID 41983379WHAT IT FOUND
For ICU nurses drawing blood from radial arterial lines, 2 mL discard was judged sufficient for blood gas and electrolyte results; 3 mL matched the control, and 1 mL did not.
Findings apply only to one catheter type.
Key findings
01After a 1 mL discard, values for carbon dioxide, bicarbonate, haemoglobin, sodium, potassium and glucose were outside clinically acceptable limits.
02After a 2 mL discard, bicarbonate and glucose differed from the 4 mL control, but those differences were not clinically meaningful.
03After a 3 mL discard, no parameters differed significantly from the 4 mL control and no values were outside the clinical acceptance interval.
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
Only 28 patients were analysed, and all were from one hospital. The result applies only to one radial arterial catheter system: 20G, 8 cm, about 1 mL dead space, with saline flush. 3 of 31 patients were excluded because they did not have all samples. The study tested common blood gas and electrolyte parameters, not all lab tests or clinical decisions. Heparinised systems may behave differently, and the authors did not test them.
Declared interests
The authors report no funding and no conflicts of interest.
The easy way to misread this
Do not apply the 2 mL discard volume to every arterial line. The study tested only one radial catheter size and system, with saline flush, in 28 patients at one hospital; other catheters, insertion sites, or heparin use may require different volumes.