GB2276468A - Optical fiber probe and junction - Google Patents

Abstract

A fibre optic probe has a probe tip 86 with a smooth face in which lies the extremity of three optical fibers and an axially extending key 94 adapted to ride on a ramp to, and mate with, a notch (48, Fig. 5) to prevent relative rotation between the tip and a side arm. The probe includes the three optical fibers, and a collar 56, the collar including a pair of camming slots 60 circumferentially spaced 180{ for co-operation with the (50, Fig. 5) of a receptor, each of the slots including a first portion (62, Fig 5) angularly related to the axis of the collar to on rotation in a first direction drive the ears towards the collar and a second portion (64, Fig. 5) angularly related to the axis to on rotation drive on the side arm ears away from the collar, and a pair of longitudinally extending grooves 58 for co-operating with the ears to allow their movement into the slots 60. The probe further includes spring support means (74, Fig. 8) and spring means 102 biasing the tip away from the collar. A junction of three plastics optical fibres in also disclosed. <IMAGE>

Description

AN OPTICAL FIBRE PROBE The invention relates to an optical fibre probe for use with medical equipment for example equipment for the measurement of blood saturation and hematpcrit.

It is known to measure hematocrit and saturation of blood by passing red light and infrared light through blood in shorter and longer paths, and using the differences in light energy remaining to calculate hematocrit and saturation.

Fused glass fiber optic connectors in a general Y configuration are known in the art.

We provide a fiber optic probe for mating with a receptor having a fluid conduit, a side arm connected sealingly with said conduit, two ears circumferentially spaced 1800 protruding perpendicularly from said side arm, and a ramp on the end of the side arm descending in height in a conduit direction into a notch also extending in said conduit direction, said probe comprising: a probe tip with a smooth face in which lies the extremity of three optical fibers and an axially extending key adapted to ride on said ramp to, and mate with, said notch to prevent relative rotation between said tip and side arm and maintain fiber optic orientation relative to said side arm, said three optical fibers a collar, said collar including a pair of camming slots circumferentially spaced 1800 for co-operation with said ears, each of said slots including a first portion angularly related to the axis of said collar to on rotation in a first direction drive said ears toward said collar and a second portion angularly related to said axis to on said rotation drive said ears away from said collar, a pair of longitudinally extending grooves for co-operation with said ears to allow their movement into said slots, and spring support means, and spring means biasing said tip away front said collar.

There is shown in the drawings, and described in the following specification, the structure of the presently preferred embodiment of the invention, and its operation.

Fig. 1 is a somewhat diagrammatic side elevational view of the preferred embodiment including an oxygenator.

Fig. 2 is a vertical sectional view of the venous inlet portion of said preferred embodiment.

Fig. 3 is a vertical sectional view of said venous inlet in its upper portion, showing one of its surrounding shrouds.

Fig. 4 is a side elevation view of said venous inlet, partially broken away and partially in section, in conjunction with the probe of the invention, shown broken away and in section.

Fig. 5 is an exploded view of portions of said venous inlet and (in vertical sectional view) said probe.

Fig. 6 is a broken-away view of a portion of said probe.

Fig. 7 is an exploded view of the portion of Fig.

6.

Fig. 8 is a sectional view of the portion of Fig.

6.

Fig. 9 is a sectional view taken at 9-9 of Fig.

8.

Fig. 10 is a sectional view taken at 10-10 of Fig. 8.

Fig. 11 is a plan view of a fiber optic element.

Fig. 12 is a side elevational view, broken away, of said probe in its relation to its control box.

Fig. 13 is an exploded view, partially broken away, of what is shown in Fig. 12.

Fig. 14 is a sectional view of the subject matter of Fig. 12, taken at 14-14 thereof.

Fig. 15 is a view, partially in section, of a sub-assembly within said control box.

Fig. 16 is an isometric view, partially broken away, of a portion of the control box.

Fig. 17 is an isometric view, partially broken away, of a portion of the control box.

Fig. 18 is a sectional view taken at 18-18 of Fig. 17.

There is shown in Fig. 1, indicated at 10, a probe of the invention, connected into venous inlet 12 of oxygenator 14 and control box 16.

In Fig. 2 is shown lower portion 18 of venous inlet 12, which is latchably interfitted with the upper portion, as shown, of oxygenator 14.

In Fig. 3 is shown upper portion 20 of venous inlet 12, surrounded over about half its periphery by plastic shroud portion 22. Inlet 12 includes an upper barb portion 24 for connection with tubing (not shown) for connection to a vein of a patient, and a molded-in metal thermometer well 26. Extending along inner bore 28 are flats 30, circumferentially spaced 1800. Also included is arterial sample line return (and drug administration) port 29, which is connected by a line (not shown) to an arterial blood sampling connection (not shown) downstream of oxygenator 14.

In Fig. 4 is shown a further view of the venous inlet 12, taken from a point of view 90" from that of Fig.

3. Flats 30 (of which there are two, located 1800 apart) define the inner surfaces of windows 32 (circumferentially spaced 1800), which are formed of transparent polycarbonate plastic. Protruding integrally as portions of venous inlet 12 are probe receiving portions 34 which include each a blind hole 36 terminating in surfaces 38 defining the inner faces of windows 32, .035 inches (8.890 x 10-4m) thick. Each portion 34 terminates in a pair of (spaced 180 and corresponding ramped) cam surfaces 40 and a pair of notches 42.

Portions 34 and most of the rest of inlet I dre surrounded by shroud members 22 and 4 (the latter not shown in Fig. 4, but being of plastic, like member 22, and being lacched- ly connected therewith in position around inlet 12).

There is shown in Fig. 5 the other shroud portion ',4, which, like shroud portion 22, includes two cam or ramp portiolls 46 circumterencially spaced 1800, and two notches 48. Iso cir- cumferentially spaced 1800.

There are also shown in Fig. 5 two ears 50. circumter- entially spaced 1800 around portion 52, each ear extending circumferentially outwardly a short distance from porticn 52.

Shroud member 22 carries in the same way a pair of ears 50.

Shroud portion 44 is shown (diagrammatically) with latch portion 54, which engages latch portions on shroud portion 22 to secure portions 22 and 4 together in circumferentidl embrace of venous inlet 12.

Shroud portions 52 fit loosely around inlet portions 34, with ramp portions 46 extending alongside ramp portions 40 in essentially common helices, and notches 48 and 42 being correspondingly sized and axially and circumferentially positioned.

Shown in Fig. 5 placed for cooperative engagement with shroud portion 52 is probe collar 56, which has a generally tubular configuration the end inside periphery of which is interrupted by a pair of longitudinally extending grooves 58 of width to just accept ears 50, and of length to enable said ears to reach camming slots (one on each side, circumferentially spaced 180 , one for each ear 50) 60 which have a first ramping portion 62 extending from related groove 58 at an angle to the collar 56 axis of 600 for a first circumferential length of 90 , and a second ramping portion 64 then at an angle to the axis of 75" for a second circumferential distance of 15".

If desired, the torque required to remove the probe end may be increased by shortening the distance between the ears 50 and a surface against which probe collar 56 abuts, as by adding shoulders to shroud 44 at the base of portion 52. This causes bending of ears 50, imposing a spring force resisting untwisting which supplements the force imposed by spring 102 The probe 10 is shown in Figs. 6 through 10.

Probe collar 56 includes slightly protruding circumferential projections 68 and longitudinal projections 70.

Internally of collar 56 are provided counterbore 72 (Fig. 8), with spring support ledge 74, and counterbore 76. The end of collar 56 away from optical windows 32 includes circumferential groove 78 and ridge 80, the latter snapped into circumferential groove 82 of elastomeric boot 84.

Extending through collar 56 is probe tip 86 which includes end portion 88 with reduced diameter extremity 89 through which extend four holes 90. Abutting portion 88 is blind hole 92, which extends to the end of probe tip 86. The walls 93 between holes 90 extend only about half way from the extremity of tip 86 to blind hole 92. Tip 86 also includes longitudinally extending alignment key 94, circumferential ledge 96, and axially extending male latching portion 98.

Held in compression between collar ledge 74 and tip ledge 96 is spring 102.

Extending from bottom of blind hole 92 to beyond tip 86 in grooves 104 is plastic divider Y 106.

Extending through three of the holes 90 and through the three zones defined with blind hole 92 by divider 106 are three optical fibers 108; these are step index optical fibers with a polymethyl-methacrylate core and transparent "flourine polymer" cladding, sold by AtIP Corporation ol Hal-risburg, Pa.

under the designation "ESLv Extra EH 4001", 1000 microns in diameter.

Epoxy potting macerial introduced through the remaining ho 1 e 90 fills that hole, the zones 206, and the spaces between blind hole 92, Y 106, and the fibers in the latter, down vertically (in Fig. 8) almost to ledge 96.

Fiber separator 106 separates fibers 108, rtduclnr: undesirable cross-calk among them. as well as in manuiacture guiding fibers 108 to the correct holes 100. Gdps 206 in the walls between holes 90 allow bending of fibers L08 as necessary to thread them from separator 106 throllgll holes 100, and facilitate potting.

Latchedly secured to tip 86 through latch 98 in hole 110 therein is plastic body 112, which carries longitudinally extending key 114 which fits in a depression (not shown) in the inner diameter surface of probe collar 56. Slot 116 enables latch 98 to ride therein until it reaches window 110. Latch 98 is ramped and rides up into window 110, into which it snaps to lock together the entire assembly. Body 112 includes larger portion 118 through which extend three holes 120. Through holes 120 extend insulated (insulation not separately shown in Fig. 10) fiber optic portions 122, held in body 112 by barbed (with small directionai barbs resisting movement in a disassembly direction only) grommets 124.

Flats 206 improve moldability and even out wall thickness.

Sheath 126 is frictionally secured in boot 84 and extends around insulated fibers 122.

The other end of probe 10 is identical with the end already described, fibers 108 extending thus from one end of the probe to the other.

One end of probe 10 is thus mounted in control box 16, as more particularly shown in Figs. 12 through 14.

There is shown a portion of wall 130 of control box 16. Extending through hole 132 therein is annulus tip 134 of bushing housing 136, in which is located elastomeric bushing 138 held in place by cast aluminum bayonet receptor 140, in which is secured fiber housing 142, through which extend optical fibers 144, which are potted in housing 142, with their ends polished in a common plane perpcndicular to the axis of receptor 140.

Receptor 140 includes ramps and notches and cars configured exactly as described above and shown ln Fig. 4 (40, b6; 42, 48; 50), except that in receptor 140 ears, ramps, and notches are all in that one part (ramps lib6, notches 148, ears 150).

Within control box 16 is subassembly 150, which includes knurled nut 152 rotatable relative to steel follower 154 in which is secured an insulated optical fiber (not shown); nut 152 is turned so that the polished end of optical fiber 156 (the ESKA fiber above specified) is longitudinally forced against the polished tip of wishbone fiber optic coupler 158, of molded styrene acrylic copolymer, sold by Polysar Inc. under the number NAS 3071.

The single end of the wishbone is supported in a groove (not shown) in support 160, to align it with fiber 156. Each of the double ends 162 of the wishbone are supported in grooves (not shown) in support 160, which aligns them respectively with infrared LED light source 164 and spherical lens 166 optically connected to red LED light source 168. Insulating spacers 170 insulate from LED's 164 and 168 springs 172 and 174, which provide abducting forces between, respectively, wishbone legs and LED 164 and lens 166.

In aperture 176 in support 160 is mounted (not shown) a light sensor for detecting light loss from wishbone 158. Slider 178 resting on a depression in support 160 enables change in the amount of energy reaching the light sensor.

In Fig. 16 box 16 is shown clamped into post 180.

Box 16 carried probe holder 182 and power cord 184 (Fig. 17; which also shows the probe end in the standardization port).

The standardization port 190 is shown in Fig. 18.

Construction here is using the same elements shown in Fig. 14, except fiber optic housing 142 is omitted, and replaced by a photographer's gray card 192 characterized by known reflectivity at the IR and red wavelengths of the LED's above mentioned. Cover 194 holds card 192 in position.

In operation, to measure both hematocrit and oxygen saturation of blood, in each new use, with one end in operating port 202 (Fig. 14), the other end of probe 10 is introduced into standardization port 190 (Fig. 18) for inspection (for probes can be defective as through fiber damage) and standardization (for even the same probe may change in its operating characteristics) To inspect, voltage outputs are measured at both the near fiber and far fiber (infra) for both red and IR, and for each at both top intensity LED output and zero intensity LED output. The resultant information tells whether the probe is defective.

Next, a photosensor output voltage of the red LED is adjusted to 5 volts, as measured by a second, received photosensor (not shown) for the near fiber, in control box 16.

(Although Fig. 9 is somewhat diagrammatic, each fiber 108 is not equidistant from each of the others. In fact, the centerlines of the three fibers, cut by a perpendicular plane, define not an equilateral triangle, but rather a triangle in which the sides have lengths of .080 inches (2.032 x 10-3m), .050 inches (1.27 x 10-3m), and .050 inches (1.27 x 10-)m); a source fiber is at one end of the .080 inch (2.032 x 10-3m) side; the fiber .050 inches (1.27 x 10-3m) from the source fiber is, of the two receiving fibers the one near the source fiber, and so is the "near fiber"; and the third fiber is the "far fiber").

If this voltage cannot be reached, the probe is defective.

The ratio of red voltage output to IR voltage output is then adjusted to 1.15, to standardize.

The end of probe 10 in standardization port 190 is then withdrawn and introduced into side arm 52 (Fig.5). Blood is made to flow through conduit 200 (Fig. 4).

Red and IR light are then alternately pulsed from LED lug8, fiber optic 162, and fiber optic 158; and from LED 164, fiber optic 162, and fiber optic 158. Fiber optic 158 has a polished end surface which is abuttingly pressed against the polished end of source fiber optic 108 (not shown in Fig. 15, but within cable 154 which extends on into tip 86 and against window 32.

Light passes in each pulse through the window and then through the flowing blood and out the near fiber 108 and far fiber 108, whence the light energy returns respectively through an abutted polished-end optical fiber in box 16 (not shown) and abutting near fiber 108, for voltage measurement by the near fiber photosensor (not shown) and through an abutted polished-end third optical fiber (not shown) in box 16, for voltage measurement by a far fiber photosensor (not shown).

The correct value of saturation is then displayed (Fig. 17), based on response from near fiber only of both IR and red, using automated known relationships.

At the same time, a value of hematocrit (based on ratio of IR responses from near fiber and far fiber) is displayed. That number must be calibrated (owing to patient valuation) by cesting a blood sample and adjusting the read- out (Fig. 17) by any difference between it and the actual laboratory analysis.

We turn now to the operation, above mencioned, oL introducing the end of probe 10 into side arm 52.

As collar 56 of probe 10 moves toward side arm 52 (Fig. 5), tip 86 moves into blind hole 36; during this move- ment ears 50 enter grooves 58 and shortly thereafter key 9'; zn tip 86 engages the upper portion of a ramp 40. Ears 50 then engage cam slot 60, and collar 56 is then rotated by hand to drive the collar toward pins 50, at the same time rotacing key 94 and driving it down a ramp 40. As ears 50 reach the 'I in which ramp 62 terminates, key 94 drops into notch 48, which prevents further rotation of tip 86 (which would adversely cause scrubbing between the surfaces of widow 32 and the polished end of probe tip 86, and would adversely affect correct orientation of optical fibers n the probe relative to the direction of blood flow). island rotation of collar 56 is then continued, to move cam portion 64 relative to ears ; slightly away therefrom, decreasing spring force, but preventing ears 50 from going on their own back along track 62. Only one of ramps 40 participates at any one time; presence of two ramps permits choice of which is to be used, which gives greater flexibility in location of the probe relative to the ears. A white line extending axially on the outer surface locates where a groove 58 is; the ramp in use depends on the ear aligned with this white line.

Spring 102 presses the polished end 204 of tip 86 against smooth window 32 (Fig. 4); leaving air gapping is of course degrading to light conduction between end 204 fiber surfaces and the window.

Ribs 68 facilitate axially moving the ends of probe 10 into or out of co-operating receptacles as described. Ribs 70 facilitate rotating those ends, in both rotational directions.

Each end of probe 10 interacts in exactly the same way with ports 202 (Fig. 14) and 190 (Fig. 18), both ends being interchangeable for each place.

Bushing 138 may be axially compressed, in the embodiments of Figs. 14 and 18, by tightening screws to bring bushing housing 136 and receptor 140 axially closer together, to impose additional friction on a probe tip 86 end therein to decrease likelihood of accidental removal. Further compression occurs when the entering probe collar is rotated. Bushing 138 also keeps the fibers in alignment, causing tip 86 and housing 142 to move together.

Circumferential projection 68 (not shown but present in Fig. 4) provides in Fig. 14 a stop causing members 140 and 142 to float toward the probe in rotation of the latter.

The receptor assembly for optically connecting a probe to a conduit may be part not only of an oxygenator, but of other medical equipment instead, including a simple in-line transport (e.g. with nothing but two barbs on a conduit from which emerges a receptor of the invention for the probe, as the oxygenator above described has such a receptor in its side arm 210 and window 32) for interposition in line with, for example, an oxygenator.

Claims (17)

1. A fiber optic probe for mating with a receptor having a fluid conduit, a side arm connected sealingly with said conduit, two ears circumferentially spaced 1800 protruding perpendicularly from said side arm, and a ramp on the end of the side arm descending in height in a conduit direction into a notch also extending in said conduit direction, said probe comprising: a probe tip with a smooth face in which lies the extremity of three optical fibers and an axially extending key adapted to ride on said ramp to, and mate with, said notch to prevent relative rotation between said tip and side arm and maintain fiber optic orientation relative to said side arm, said three optical fibers a collar, said collar including a pair of camming slots circumferentially spaced 1800 for co-operation with said ears, each of said slots including a first portion angularly related to the axis of said collar to on rotation in a first direction drive said ears toward said collar and a second portion angularly related to said axis to on said rotation drive said ears away from said collar, a pair of longitudinally extending grooves for co-operation with said ears to allow their movement into said slots, and spring support means, and spring means biasing said tip away from said collar.

2. The probe of Claim 1 in which each end of the probe includes all the limitations of Claim 1.

3. The probe of Claim 1 or 2 in which said first portion is at an angle of 60 to said axis and has a circumferential length of 90" and said second portions at an angle of 75" to said axis and has a circumferential length of 150. .

4. The probe of any of Claims 1-3 in which said ramps are integral and said ramps are on a single part only.

5. The probe of any of Claims 1-4 which further includes an elastomeric bushing arranged to accept said probe collar.

6. The probe of any of Claims 1-5 in combination with a control box with an operating port configured to cooperate with the probe to move and position said probe tip against a surface including said optical fibers.

7. The probe of any preceding claim, in which the first of said optical fibers is joined to the second of said optical fibers and both are joined in moulded juncture to the third optical fiber said fibers being of integrally moulded plastic.

8. The probe of Claim 7 in which said juncture is in the configuration of a Y.

9. A control box with an operating port configured to co-operate with the probe of Claim 1 to move and position said probe tip as in Claim 1 against a surface including said optical fibers, first optical light generating means optically connected to a first of said optical fibers and second optical light generating means optically connected to a second of said optical fibers.

10. The control box of Claim 9 in which said first of said optical fibers is joined to said second of said optical fibers and both are joined in moulded juncture to a third optical fiber said fibers being of integrally moulded plastic.

11. The control box of Claim 1Q in which said juncture is in the configuration of a Y.

12. The control box of Claim 9 which includes a testing port configured to co-operate with a probe of Claim 1 to move and position said probe tip as in Claim 1 spaced from a reflective surface.

13. The control box of Claim 9 which includes aperture for receiving light from an optical fiber and adjustable aperture opening size means.

14. The fiber optic connector configured as set forth in Claim 10.

15. The fiber optic connector configured as in Claim 11.

16. A fiber optic probe for mating with a receptor substantially as hereinbefore described with reference to and as shown in figures 1, 4-14, and 16-18 of the accompanying drawings.

17. A control box substantially as hereinbefore described with reference to and as shown in Figures 12-15 of the accompanying drawings.