Syringe dead space: difference between revisions

Diff·revision 12 → 13·01:08, 3 Dec 2025

Difference between revision 12 and revision 13 of Syringe dead space. 16 lines changed; the page grew by 2,627 bytes.

Revision 12 — 18:21, 21 Nov 2025 MicrodoseMagnus (talk) add the preservative point: unpreserved diluent changes the interval 12,801 bytes +1,645	Revision 13 — 01:08, 3 Dec 2025 GramsNotUnitsGil (talk) add the shelf life after first puncture, attributed 15,428 bytes +2,627
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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}}
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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}}
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+		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
+		106	== Low-dead-space devices ==
+		107	Interest in reducing dead space arose in two unrelated fields.
+		108
+		109	In injecting-drug-use epidemiology, the retained volume determines how much blood a syringe carries between users. Modelling work has argued that widespread substitution of low-dead-space devices would materially reduce transmission of blood-borne viruses, on the basis that the residual blood volume — and therefore the inoculum — is reduced by more than an order of magnitude. The argument is a modelling argument supported by laboratory measurement of retained blood volume rather than by a trial of transmission outcomes, and it has been presented as such.{{r\|zule2009,zule2013,bobashev2010}}
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+		111	In vaccination and pandemic preparedness, dead space determines how many doses can be drawn from a fixed vial, and therefore how far a constrained supply extends. Analyses during influenza-preparedness planning noted that substituting devices of a few microlitres of dead space for devices of 70–80 µL could increase the number of doses obtainable from a multi-dose presentation by a substantial fraction, and that the effect is proportionally larger the smaller the dose.{{r\|strauss2006,who2015}}
+		112
100	== References ==	113	== References ==
101	{{reflist}}	114	{{reflist}}
102	<ref name="zule2009">Zule WA, Bobashev G. "High dead-space syringes and the risk of HIV and HCV infection among injecting drug users." ''Drug and Alcohol Dependence'' 100(3):204–213 (2009).</ref>	115	<ref name="zule2009">Zule WA, Bobashev G. "High dead-space syringes and the risk of HIV and HCV infection among injecting drug users." ''Drug and Alcohol Dependence'' 100(3):204–213 (2009).</ref>
103	<ref name="zule2013">Zule WA, Cross HE, Stover J, Pretorius C. "Are major reductions in new HIV infections possible with people who inject drugs? The case for low dead-space syringes in highly affected countries." ''International Journal of Drug Policy'' 24(1):1–7 (2013).</ref>	116	<ref name="zule2013">Zule WA, Cross HE, Stover J, Pretorius C. "Are major reductions in new HIV infections possible with people who inject drugs? The case for low dead-space syringes in highly affected countries." ''International Journal of Drug Policy'' 24(1):1–7 (2013).</ref>
+		117	<ref name="bobashev2010">Bobashev GV, Zule WA. "Modeling the effect of high dead-space syringes on the human immunodeficiency virus (HIV) epidemic among injecting drug users." ''Addiction'' 105(8):1439–1447 (2010).</ref>
104	<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>	118	<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>
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>	119	<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>	120	<ref name="iso7886">ISO 7886-1:2017, ''Sterile hypodermic syringes for single use — Part 1: Syringes for manual use''. International Organization for Standardization.</ref>
+		121	<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>	122	<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>	123	<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>
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115	* [[Insulin syringe unit conversion]]	130	* [[Insulin syringe unit conversion]]
116	* [[Reconstitution calculator]]	131	* [[Reconstitution calculator]]
+		132	* [[Multi-dose vial]]
117		133
118	{{DEFAULTSORT:Syringe dead space}}	134	{{DEFAULTSORT:Syringe dead space}}