Syringe dead space: difference between revisions
Diff·revision 6 → 7·09:46, 11 Oct 2025
Difference between revision 6 and revision 7 of Syringe dead space. 5 lines changed; the page grew by 662 bytes.
| Revision 6 — 20:27, 1 Oct 2025 UnitAuditUwe (talk) expand §Measurement and standards 7,949 bytes +2,030 | Revision 7 — 09:46, 11 Oct 2025 BalanceBirdie (talk) space between number and unit per PP:MOS 8,611 bytes +662 | ||
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| 1 | {{Infobox concept | 1 | {{Infobox concept |
| 2 | | name = Syringe dead space | 2 | | name = Syringe dead space |
| + | 3 | | image = syringe.svg | |
| + | 4 | | caption = Dead space lies distal to the plunger tip at full depression: the hub cavity, the needle lumen and any recess in the plunger face. | |
| 3 | | Also known as = Residual volume; hold-up volume; wastage volume | 5 | | Also known as = Residual volume; hold-up volume; wastage volume |
| 4 | | Location = Needle hub, needle lumen, plunger-tip recess | 6 | | Location = Needle hub, needle lumen, plunger-tip recess |
| ⋮ | ⋮ | ||
| 61 | | 31G | 0.261 mm | 0.133 mm | 0.18 µL | | 63 | | 31G | 0.261 mm | 0.133 mm | 0.18 µL | |
| 62 | 64 | ||
| + | 65 | Volumes are computed as the product of cross-sectional area and length; outside diameters follow the metric equivalents of the Birmingham gauge series used in ISO 9626, and inside diameters are typical regular-wall values.{{r|iso9626}} A 27G half-inch needle therefore holds 0.44 µL, roughly one part in 160 of a 70 µL hub. Changing needle gauge or length has almost no effect on dead space; changing the hub design changes it by an order of magnitude. | |
| + | 66 | ||
| 63 | === Effect of needle length === | 67 | === Effect of needle length === |
| 64 | Doubling cannula length from 12.7 mm to 25.4 mm doubles the lumen volume, taking a 25G needle from 0.67 to 1.34 µL. Against a hub of 60–70 µL this is immaterial. Needle length is selected on anatomical grounds — 4, 6 and 8 mm pen needles and 12.7 mm syringe needles are the common lengths for [[Subcutaneous injection|subcutaneous administration]] — and not on dead-space grounds.{{r|iso7864}} | 68 | Doubling cannula length from 12.7 mm to 25.4 mm doubles the lumen volume, taking a 25G needle from 0.67 to 1.34 µL. Against a hub of 60–70 µL this is immaterial. Needle length is selected on anatomical grounds — 4, 6 and 8 mm pen needles and 12.7 mm syringe needles are the common lengths for [[Subcutaneous injection|subcutaneous administration]] — and not on dead-space grounds.{{r|iso7864}} |
| ⋮ | ⋮ | ||
| 78 | [[Category:Dosing and titration]] | 82 | [[Category:Dosing and titration]] |
| 79 | [[Category:Preparation and handling]] | 83 | [[Category:Preparation and handling]] |
| + | 84 | [[Category:Clinical practice]] | |
| 80 | 85 |