Syringe dead space: difference between revisions
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| 24 | Terminology in the literature is inconsistent. ''Dead space'', ''dead volume'', ''residual volume'' and ''hold-up volume'' are all used for the same quantity, and ''residual volume'' is also used in a different sense for liquid left in the source container after withdrawal. The two are separate: the liquid left in a [[vial]] because the needle cannot reach it, or because the vial geometry traps it, is a container property and is discussed at [[Underfilling|underfilling]] and at [[Vial|vial]]. This article uses ''dead space'' for the syringe-and-needle quantity only.{{r|iso7886}} | 24 | Terminology in the literature is inconsistent. ''Dead space'', ''dead volume'', ''residual volume'' and ''hold-up volume'' are all used for the same quantity, and ''residual volume'' is also used in a different sense for liquid left in the source container after withdrawal. The two are separate: the liquid left in a [[vial]] because the needle cannot reach it, or because the vial geometry traps it, is a container property and is discussed at [[Underfilling|underfilling]] and at [[Vial|vial]]. This article uses ''dead space'' for the syringe-and-needle quantity only.{{r|iso7886}} |
| 25 | 25 | ||
| + | 26 | The distinction between ''high dead-space'' and ''low dead-space'' devices entered the literature through injecting-drug-use epidemiology, where the retained volume determines how much blood a shared syringe can transfer. Low-dead-space designs achieve their reduction either by moulding the needle permanently into a plunger-penetrable hub, or by fitting a plastic insert into an otherwise standard Luer hub so that the plunger tip advances into it.{{r|zule2013}} | |
| + | 27 | ||
| + | 28 | == Measured and computed magnitudes == | |
| + | 29 | Published measurements are made gravimetrically: the assembled device is filled, fully discharged, and the retained mass determined by weighing, with density assumed. Values below are representative of those reported in the injection-equipment literature and vary between manufacturers of nominally equivalent devices.{{r|zule2009,zule2013}} | |
| + | 30 | ||
| + | 31 | |+ Dead space by device configuration | |
| + | 32 | | !Configuration | Dead space | Dominant cavity | | |
| + | 33 | |---|---|---| | |
| + | 34 | | 1 mL insulin syringe, permanently attached 29–31G needle | 0.002–0.006 mL | Plunger-tip recess | | |
| + | 35 | | 1 mL syringe, Luer slip, 25G × 16 mm detachable needle | ≈0.070 mL | Hub | | |
| + | 36 | | 3 mL syringe, Luer lock, 21G × 25 mm detachable needle | 0.080–0.100 mL | Hub | | |
| + | 37 | | Luer hub with no needle fitted | ≈0.060 mL | Hub | | |
| + | 38 | | Low-dead-space insert needle on a Luer hub | ≈0.010 mL | Residual hub void | | |
| + | 39 | ||
| + | 40 | The consistent finding is that the hub dominates. This is counter-intuitive, because the needle is the visibly narrow and visibly long component, but the arithmetic is unambiguous once the lumen volume is computed from tubing dimensions.{{r|iso9626}} | |
| + | 41 | ||
| 26 | == References == | 42 | == References == |
| 27 | {{reflist}} | 43 | {{reflist}} |
| ⋮ | ⋮ | ||
| 30 | <ref name="strauss2006">Strauss K, van Zundert A, Frid A, Costigliola V. "Pandemic influenza preparedness: the critical role of the syringe." ''Vaccine'' 24(24):4874–4882 (2006).</ref> | 46 | <ref name="strauss2006">Strauss K, van Zundert A, Frid A, Costigliola V. "Pandemic influenza preparedness: the critical role of the syringe." ''Vaccine'' 24(24):4874–4882 (2006).</ref> |
| 31 | <ref name="iso7886">ISO 7886-1:2017, ''Sterile hypodermic syringes for single use — Part 1: Syringes for manual use''. International Organization for Standardization.</ref> | 47 | <ref name="iso7886">ISO 7886-1:2017, ''Sterile hypodermic syringes for single use — Part 1: Syringes for manual use''. International Organization for Standardization.</ref> |
| + | 48 | <ref name="iso9626">ISO 9626:2016, ''Stainless steel needle tubing for the manufacture of medical devices — Requirements and test methods''. International Organization for Standardization.</ref> | |
| 32 | 49 | ||
| 33 | {{DEFAULTSORT:Syringe dead space}} | 50 | {{DEFAULTSORT:Syringe dead space}} |