French catheter scale

Technopedia Center

Faculty of Engineering and Computer Science
S1 Informatics S1 Information Systems S1 Information Technology S1 Computer Engineering S1 Electrical Engineering S1 Civil Engineering

faculty of Economics and Business
S1 Management S1 Accountancy

Faculty of Letters and Educational Sciences
S1 English literature S1 English language education S1 Mathematics education S1 Sports Education

French catheter scale

From Wikipedia, the free encyclopedia

(Redirected from French gauge)

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "French catheter scale" – news · newspapers · books · scholar · JSTOR (July 2011) (Learn how and when to remove this message)

The French scale, French gauge or Charrière system is commonly used to measure the size of a catheter. It is most often abbreviated as Fr, but can often be seen abbreviated as Fg, FR or F. It may also be abbreviated as CH or Ch (for Charrière, its inventor). However, simply gauge, G or GA generally refers to Birmingham gauge.^[1]

The Charrière is measured by the ''outer'' diameter, and is defined as 1 Fr = 1/3 mm, and thus 1 mm = 3 Fr; therefore the diameter of a round catheter in millimetres can be determined by dividing the French size by 3.^[2] The French units roughly correspond to the outer circumference of the catheter (see table below).

For example, if the French size is 9, the diameter is 9/3 = 3.07 mm. It is seen that the French unit is fully redundant with the metric system but introduces potential for rounding errors. This metrication problem is further complicated by the mixed use of metric and imperial units in medical professions using catheters.

An increasing French size corresponds to a larger external diameter. This is contrary to Birmingham gauge, where an increasing gauge corresponds to a smaller diameter needle.

The French size is a measure of the outer diameter of a catheter (not internal drainage channel, or inner diameter). So, for example, if a two-way catheter of 20 Fr is compared to a 20 Fr three-way catheter, they both have the same external diameter but the two-way catheter will have a larger drainage channel than the three-way. Three-way catheters accommodate an extra channel for irrigation within a similar external diameter.

The French gauge was devised by Joseph-Frédéric-Benoît Charrière, a 19th-century Parisian maker of surgical instruments, who defined the "diameter in mm times 3" relationship.^[3]

Size correspondence

[edit]

French gauge	Circumference (mm)	Outer diameter
French gauge	Circumference (mm)	(mm)	(inches)
2	2.1	0.67	0.026
3	3.1	1.00	0.039
4	4.2	1.33	0.053
5	5.2	1.67	0.066
6	6.3	2.00	0.079
7	7.3	2.33	0.092
8	8.4	2.67	0.11
9	9.4	3.00	0.12
10	10.5	3.33	0.13
11	11.5	3.67	0.14
12	12.6	4.00	0.16
13	13.6	4.33	0.17
14	14.7	4.67	0.18
15	15.7	5.00	0.20
16	16.8	5.33	0.21
17	17.8	5.67	0.22
18	18.9	6.00	0.24
19	19.9	6.33	0.25
20	20.9	6.67	0.26
22	23.0	7.33	0.29
24	25.1	8.00	0.32
26	27.2	8.67	0.34
28	29.3	9.33	0.37
30	31.4	10.00	0.39
32	33.5	10.67	0.42
34	35.6	11.33	0.45

References

[edit]

^ Poll, J. S. (1999). "The story of the gauge". Anaesthesia. 54 (6): 575–581. doi:10.1046/j.1365-2044.1999.00895.x. ISSN 0003-2409. PMID 10403873. S2CID 41519791.
^ "1 French". Wolfram|Alpha. Retrieved 20 March 2012.
^ Iserson, Kenneth V. (1987). "J.-F.-B. Charrière: The man behind the "French" gauge". Journal of Emergency Medicine. 5 (6): 545–8. doi:10.1016/0736-4679(87)90218-6. PMID 3323304.

Retrieved from "https://en.wikipedia.org/w/index.php?title=French_catheter_scale&oldid=1261056005"

Categories:

Hidden categories:

Size correspondence

See also

References