French catheter scale: Difference between revisions
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{{SI}} | {{SI}} | ||
{{CMG}} | {{CMG}} | ||
{{ | {{SK}} Ch, F, Fr, FR | ||
==Overview== | ==Overview== | ||
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The '''French catheter scale''' (most correctly abbreviated as Fr, but also often abbreviated as FR or F) is commonly used to measure the outer circumference of cylindrical medical instruments including [[catheter]]s. In the '''French Gauge''' system as it is also known, the diameter in millimeters of the catheter can be determined by dividing the French size by 3, thus an increasing French size corresponds with a larger diameter catheter. The following equations summarize the relationships: | The '''French catheter scale''' (most correctly abbreviated as Fr, but also often abbreviated as FR or F) is commonly used to measure the outer circumference of cylindrical medical instruments including [[catheter]]s. In the '''French Gauge''' system as it is also known, the diameter in millimeters of the catheter can be determined by dividing the French size by 3, thus an increasing French size corresponds with a larger diameter catheter. The following equations summarize the relationships: | ||
D(mm) = Fr/ | D(mm) = Fr/3 | ||
For example, if the French size is 9, the diameter is 3 mm. Note: the French scale is equal to the diameter in mm multiplied by '''three''', not the circumference (diameter times π) as is sometimes thought. | or | ||
Fr = D(mm)*3 | |||
For example, if the French size is 9, the diameter is 3 mm. | |||
''Note: the French scale is equal to the diameter in mm multiplied by '''three''', not the circumference (diameter times π) as is sometimes thought.'' | |||
This is contrary to needle-gauge size, where the diameter is 1/gauge inches; thus the larger the gauge needle, the more narrow the bore of the needle. | This is contrary to needle-gauge size, where the diameter is 1/gauge inches; thus the larger the gauge needle, the more narrow the bore of the needle. | ||
| Line 17: | Line 23: | ||
The [[Stubs Iron Wire Gauge]] system is also commonly used in a medical setting and is in fact more common for measuring needles, even though many find the Stubs system to be more confusing because the scale is non-linear and inversely proportional. | The [[Stubs Iron Wire Gauge]] system is also commonly used in a medical setting and is in fact more common for measuring needles, even though many find the Stubs system to be more confusing because the scale is non-linear and inversely proportional. | ||
==Size Correspondence== | |||
1 Fr is equivalent to 0.33 mm = .013" = 1/77" of diameter. Thus the size in French units is roughly equal to the circumference of the catheter in millimeters. | |||
{| style="float: right;" | |||
| [[Image:French catheter scale.gif|thumb|right|400px|Sizing scale of the French catheter system]] | |||
|} | |||
{| class="wikitable" width="240" align="center" | {| class="wikitable" width="240" align="center" | ||
| Line 30: | Line 38: | ||
|- align="center" | |- align="center" | ||
| 3 | | 3 | ||
| 1 | | 1.00 | ||
| 0.039 | | 0.039 | ||
|- align="center" | |- align="center" | ||
| 4 | | 4 | ||
| 1. | | 1.33 | ||
| 0.053 | | 0.053 | ||
|- align="center" | |- align="center" | ||
| Line 42: | Line 50: | ||
|- align="center" | |- align="center" | ||
| 6 | | 6 | ||
| 2 | | 2.00 | ||
| 0.079 | | 0.079 | ||
|- align="center" | |- align="center" | ||
| 7 | | 7 | ||
| 2. | | 2.33 | ||
| 0.092 | | 0.092 | ||
|- align="center" | |- align="center" | ||
| 8 | | 8 | ||
| 2. | | 2.67 | ||
| 0.105 | | 0.105 | ||
|- align="center" | |- align="center" | ||
| 9 | | 9 | ||
| 3 | | 3.00 | ||
| 0.118 | | 0.118 | ||
|- align="center" | |- align="center" | ||
| 10 | | 10 | ||
| 3. | | 3.33 | ||
| 0.131 | | 0.131 | ||
|- align="center" | |- align="center" | ||
| 11 | | 11 | ||
| 3. | | 3.67 | ||
| 0.144 | | 0.144 | ||
|- align="center" | |- align="center" | ||
| 12 | | 12 | ||
| 4 | | 4.00 | ||
| 0.158 | | 0.158 | ||
|- align="center" | |- align="center" | ||
| 13 | | 13 | ||
| 4. | | 4.33 | ||
| 0.170 | | 0.170 | ||
|- align="center" | |- align="center" | ||
| 14 | | 14 | ||
| 4. | | 4.67 | ||
| 0.184 | | 0.184 | ||
|- align="center" | |- align="center" | ||
| 15 | | 15 | ||
| 5 | | 5.00 | ||
| 0.197 | | 0.197 | ||
|- align="center" | |- align="center" | ||
| 16 | | 16 | ||
| 5. | | 5.33 | ||
| 0.210 | | 0.210 | ||
|- align="center" | |- align="center" | ||
| 17 | | 17 | ||
| 5. | | 5.67 | ||
| 0.223 | | 0.223 | ||
|- align="center" | |- align="center" | ||
| 18 | | 18 | ||
| 6 | | 6.00 | ||
| 0.236 | | 0.236 | ||
|- align="center" | |- align="center" | ||
| 19 | | 19 | ||
| 6. | | 6.33 | ||
| 0.249 | | 0.249 | ||
|- align="center" | |- align="center" | ||
| 20 | | 20 | ||
| 6. | | 6.67 | ||
| 0.263 | | 0.263 | ||
|- align="center" | |- align="center" | ||
| 22 | | 22 | ||
| 7. | | 7.33 | ||
| 0.288 | | 0.288 | ||
|- align="center" | |- align="center" | ||
| 24 | | 24 | ||
| 8 | | 8.00 | ||
| 0.315 | | 0.315 | ||
|- align="center" | |- align="center" | ||
| 26 | | 26 | ||
| 8. | | 8.67 | ||
| 0.341 | | 0.341 | ||
|- align="center" | |- align="center" | ||
| 28 | | 28 | ||
| 9. | | 9.33 | ||
| 0.367 | | 0.367 | ||
|- align="center" | |- align="center" | ||
| 30 | | 30 | ||
| 10 | | 10.0 | ||
| 0.393 | | 0.393 | ||
|- align="center" | |- align="center" | ||
| Line 129: | Line 137: | ||
| 0.445 | | 0.445 | ||
|} | |} | ||
==Historical Perspective== | |||
The '''French Gauge''' was devised by Joseph-Frédéric-Benoît Charrière, a 19th century Parisian maker of surgical instruments, who defined the "diameter times 3" relationship. | |||
In some countries (especially French speaking), this unit is called '''Charriere''' and abbreviated as '''Ch'''. | |||
==References== | ==References== | ||
This chart taken from [http://www.texloc.com/closet/cl_french_scale.html Texloc] | This chart taken from [http://www.texloc.com/closet/cl_french_scale.html Texloc] | ||
==See also== | ==See also== | ||
* [[Needle gauge comparison chart]] | * [[Needle gauge comparison chart]] | ||
[[Category:Angiopedia]] | |||
[[Category:Medical equipment]] | [[Category:Medical equipment]] | ||
[[Category:Wire gauges]] | [[Category:Wire gauges]] | ||
Latest revision as of 22:27, 6 April 2014
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: Ch, F, Fr, FR
Overview
The French catheter scale (most correctly abbreviated as Fr, but also often abbreviated as FR or F) is commonly used to measure the outer circumference of cylindrical medical instruments including catheters. In the French Gauge system as it is also known, the diameter in millimeters of the catheter can be determined by dividing the French size by 3, thus an increasing French size corresponds with a larger diameter catheter. The following equations summarize the relationships:
D(mm) = Fr/3
or
Fr = D(mm)*3
For example, if the French size is 9, the diameter is 3 mm.
Note: the French scale is equal to the diameter in mm multiplied by three, not the circumference (diameter times π) as is sometimes thought.
This is contrary to needle-gauge size, where the diameter is 1/gauge inches; thus the larger the gauge needle, the more narrow the bore of the needle.
The Stubs Iron Wire Gauge system is also commonly used in a medical setting and is in fact more common for measuring needles, even though many find the Stubs system to be more confusing because the scale is non-linear and inversely proportional.
Size Correspondence
1 Fr is equivalent to 0.33 mm = .013" = 1/77" of diameter. Thus the size in French units is roughly equal to the circumference of the catheter in millimeters.
 |
| French Gauge |
Diameter (mm) |
Diameter (inches) |
| 3 | 1.00 | 0.039 |
| 4 | 1.33 | 0.053 |
| 5 | 1.67 | 0.066 |
| 6 | 2.00 | 0.079 |
| 7 | 2.33 | 0.092 |
| 8 | 2.67 | 0.105 |
| 9 | 3.00 | 0.118 |
| 10 | 3.33 | 0.131 |
| 11 | 3.67 | 0.144 |
| 12 | 4.00 | 0.158 |
| 13 | 4.33 | 0.170 |
| 14 | 4.67 | 0.184 |
| 15 | 5.00 | 0.197 |
| 16 | 5.33 | 0.210 |
| 17 | 5.67 | 0.223 |
| 18 | 6.00 | 0.236 |
| 19 | 6.33 | 0.249 |
| 20 | 6.67 | 0.263 |
| 22 | 7.33 | 0.288 |
| 24 | 8.00 | 0.315 |
| 26 | 8.67 | 0.341 |
| 28 | 9.33 | 0.367 |
| 30 | 10.0 | 0.393 |
| 32 | 10.7 | 0.419 |
| 34 | 11.3 | 0.445 |
Historical Perspective
The French Gauge was devised by Joseph-Frédéric-Benoît Charrière, a 19th century Parisian maker of surgical instruments, who defined the "diameter times 3" relationship.
In some countries (especially French speaking), this unit is called Charriere and abbreviated as Ch.
References
This chart taken from Texloc