Syringe dead space: difference between revisions
Diff·revision 28 → 29·01:41, 6 Dec 2025
Difference between revision 28 and revision 29 of Syringe dead space. 7 lines changed; the page grew by 1,185 bytes.
| Revision 28 — 10:01, 30 Nov 2025 TrialsTabitha (talk) remove weasel wording 12,801 bytes +468 | Revision 29 — 01:41, 6 Dec 2025 ArchiveBot (talk) bot: sort category members 13,986 bytes +1,185 | ||
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| 21 | }} | 21 | }} |
| 22 | {{hatnote|For the devices in which dead space is measured, see [[Insulin syringe]]. For the volume arithmetic of a reconstituted vial, see [[Reconstitution calculator]].}} | 22 | {{hatnote|For the devices in which dead space is measured, see [[Insulin syringe]]. For the volume arithmetic of a reconstituted vial, see [[Reconstitution calculator]].}} |
| + | 23 | {{technical|date=May 2026|talk=The 35% figure is being read as a dose error in every case}} | |
| 23 | 24 | ||
| 24 | '''Syringe dead space''' is the volume of liquid that remains inside a syringe and its needle after the plunger has been fully depressed. It occupies the cavity of the needle hub, the lumen of the needle itself and any recess in the face of the plunger tip, and it is not delivered to the injection site.{{r|zule2009}} | 25 | '''Syringe dead space''' is the volume of liquid that remains inside a syringe and its needle after the plunger has been fully depressed. It occupies the cavity of the needle hub, the lumen of the needle itself and any recess in the face of the plunger tip, and it is not delivered to the injection site.{{r|zule2009}} |
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| 98 | Two configurations make the error more likely. A detachable needle attached after the barrel has been filled introduces a hub full of air that must then be displaced. Reconstitution performed with one needle and injection with another — a common arrangement, since a wider gauge is easier to use for withdrawal — reintroduces an air-filled hub at the point of exchange. Neither is inherently unsafe, but both place the burden of correctness on a step that is easy to omit and whose omission is not visible afterwards.{{r|strauss2006}} | 99 | Two configurations make the error more likely. A detachable needle attached after the barrel has been filled introduces a hub full of air that must then be displaced. Reconstitution performed with one needle and injection with another — a common arrangement, since a wider gauge is easier to use for withdrawal — reintroduces an air-filled hub at the point of exchange. Neither is inherently unsafe, but both place the burden of correctness on a step that is easy to omit and whose omission is not visible afterwards.{{r|strauss2006}} |
| 99 | 100 | ||
| + | 101 | === Effect on dose accuracy tolerances === | |
| + | 102 | ISO 7886-1 specifies that a syringe deliver its graduated volume within a stated tolerance when used according to the manufacturer's instructions, which include expulsion of air. At nominal capacity the tolerance is ±5%; at low fractions of capacity the permitted deviation is larger in relative terms, because it is expressed against a fixed fraction of nominal volume rather than against the volume drawn. A 1 mL syringe used to deliver 0.10 mL is therefore operating in a region where the device standard itself concedes poor relative accuracy, independent of dead space.{{r|iso7886,iso8537}} | |
| + | 103 | ||
| + | 104 | This is a separate error source from dead space and the two are additive. Insulin syringes carry the tighter requirements of ISO 8537 and are graduated in units rather than in millilitres, which introduces the conversion problem discussed at [[Insulin syringe unit conversion]].{{r|iso8537}} | |
| + | 105 | ||
| 100 | == References == | 106 | == References == |
| 101 | {{reflist}} | 107 | {{reflist}} |
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| 105 | <ref name="who2015">World Health Organization. ''WHO Guideline on the Use of Safety-Engineered Syringes for Intramuscular, Intradermal and Subcutaneous Injections in Health Care Settings''. Geneva (2015).</ref> | 111 | <ref name="who2015">World Health Organization. ''WHO Guideline on the Use of Safety-Engineered Syringes for Intramuscular, Intradermal and Subcutaneous Injections in Health Care Settings''. Geneva (2015).</ref> |
| 106 | <ref name="iso7886">ISO 7886-1:2017, ''Sterile hypodermic syringes for single use — Part 1: Syringes for manual use''. International Organization for Standardization.</ref> | 112 | <ref name="iso7886">ISO 7886-1:2017, ''Sterile hypodermic syringes for single use — Part 1: Syringes for manual use''. International Organization for Standardization.</ref> |
| + | 113 | <ref name="iso8537">ISO 8537:2016, ''Sterile single-use syringes, with or without needle, for insulin''. International Organization for Standardization.</ref> | |
| 107 | <ref name="iso7864">ISO 7864:2016, ''Sterile hypodermic needles for single use — Requirements and test methods''. International Organization for Standardization.</ref> | 114 | <ref name="iso7864">ISO 7864:2016, ''Sterile hypodermic needles for single use — Requirements and test methods''. International Organization for Standardization.</ref> |
| 108 | <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> | 115 | <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> |