US 3373735 A
Description (OCR text may contain errors)
J. P. GALLAGHl-:R 3,373,735
MEDICAL-SURGICAL TUBE Filed oct. 21, 1965 vg, IO :sa G O O @I @OOO Bywgwu ATTORNEYS United States Patent O 3,373,735 MEDICAL-SURGICAL TUBE .lohn P. Gallagher, 2415 Foxhall Road NW.,
` Washington, D.C. 20007 Filed Oct. 21, 1965, Ser. No. 500,118 7 Claims. (Cl. 12S-2) This invention relates to an improved medical-surgical tube and in particular to such a tube having a colorchange acid-base indicator means associa-ted `therewith.
In many surgical or clinical procedures, in which tubes or catheters are employed, it is essential to be able to determine the location of the outlet or distal end o-f the tube within the body of the patient. One important and common use of medical-surgical tubes is for feeding patients wherein a feeding tube is inserted through one of the nostrils into the stomach of the patient. After the tube is lodged in the stomach, the desired fluids may 'be forced through the tubel directly int-o the patients stomach. However, .it is not uncommon, in passing the distal en-d of the tube from the nasal cavity toward the stomach, that the distal end enters the traohea whereby the distal end lodges in a lung rather than the stomach of a patient. Forcing of fluids into such a mislocated tube could result in undesirable complications.
l/Iedieal-.surgical tubes having X--ray o-paque portions are known whereby directing7 a beam of X-rays through the body of a patient in the neighborhood of the inserted tube while observing the relative position of the tube a skilled technician or a physician could determine whether the feeding tube is correctly positioned in the stomach or incorrectly positioned in a lung of the patient. While the use of the X-ray technique for determining the position of medical-surgical tubes will provide the desired result-s such techniques require substantial skills and considerable time and equipment.
I-t is, therefore, a principal object of the present invention to provide a simple, relatively inexpensive, medicalsurgical tube having incorporated therein a color-change acid-base indicator means whereby it may be simply, quickly and inexpensively determined if, for example, the distal end of a feeding tube is correctly positioned in a patients stomach by merely determining the color of a color indicator which has 'been bathed in the body fluid surrounding the distal end of the tube.
These and other objects and advantages of the present invention are provided by a medical-surgical tube having an internal end portion adapted to be inserted within a body cavity and an external end portion adapted to remain outside of the body, a color-change indicator carrier means associated with the external end portion of the tube and means providing liquid communication between the inner wall of the tube and said indicator carrier means.
The invention will be more particularly described with specic reference to a stom-ach tube and in conjunction with the illustrative embodiments of the invention sho-wn in the drawings wherein:
FIGURE l is a diagrammatic view of the upper portion of the human head illustrating one method of positioning a stomach tube through the nasal passage into the stomach of the patient;
FIGURE 2 is a section on line 2 2 of FIGURE l;
FIGURE 3 is a transverse section on line 3-3 of FIGURE 2;
FIGURE 4 is a transverse section .simil-ar to that illustrated in FIGURE 2 of a further form of the present invention; and
FIGURE 5 is a longitudinal sectional view similar to that shown in FIGURE 3 of a further form of the improved medioal-surgical tube of the invention.
Referring to the drawings and in particular to FIG- ICC URES l, 2 and 3, 10 generally designates a stomach tube constructed in accordance with the present invention.
The tube 10 has a distal, or internal end portion 14 and an external end portion 12. In FIGURE l the stomach tube 10 is4 shown passing through a nostril of a patient 15, down through the esophagus 18, thence to the stomach indicated by the reference arrow. Also in FIG- URE l, in broken lines, there is illustrated the tube 10 passing through the nasal passage of the patient 15 and into the larynx, through the trachea thence into the lungs in a manner not desired where the tube 10 is to be used to feed the patient 15.
Now referring particularly to FIGURES 2 and 3, adjacent the external end portion 12 of the tube 10 an absorbent piaper ring 22 is molded within the tu'be intermediate the outer wall 24 and the inner wall 26 .with the axis of the ring of absorbent paper 22 being generally coaxial with the axis of the bore of the tube. A plurality of perforations 28 pass through ythe inner wall 26 o'f the tube 10 to the inner surface 30 of the absorbent paper ring 22 whereby liquid within the tube will bath the absorbent paper. In this form of the invention the absorbent paper 22 provides a carrier means for a colorchange indicator. Preferably the color-change indicator is of the acid-base type and as used herein the color-change indicator is a substance which is used for the visual detection and determination of a specific constituent present in a liquid or mixture of liquids.
In general, indicators for the detection of acids and bases consist of substance that undergo visual change Within :a predetermined limited range of hydrogen iron ooncentrationjMany such indicators are known in the art. Of the well-known indicators, litmus, a blue coloring matter from various species of liohens, particularly Vrariolaria, has been found to be a very satisfactory colorchange acid-base indicato-r for the improved stomach tube. Litmus is partially soluble in water or alcohol and when used as .an acid-base indicator it turns red at pH 4.5 and blue .at pH 8.3. Litmus is non-toxis and in view of its nontoxi-mity has been used as a coloring agent for beve-rages.
Prior to sale of the improved medical-surgical tube, the carrier 22 or the color-change indicator is charged with for example a litmus solution which after drying remainswithin the carrier..
Other useful color-change acid-base indicators are set forth in the following table with their color characterisitics:
TAB LE I Trade Name Methyl Orange Phenol Red Phenolphthalein.
In operation of the stomach tube hereinabove described with reference to the FIGURES 1 through 3, after the tube is inserted in the stomach of a patient a small amount of the fluid present in the body adjacent the distal end is drawn into the tube to pass through the openings 28 and thus wet the color-change indicator carrier 22. If the distal end of the tube is properly within the stomach of the patient, and if the indicator is, for example, litmus the absorbent paper 22 will turn red as, on the average the pH of stomach juices is about 1 to about 2. If, however, the distal end of the tube has become improperly lodged in the lungs, the color indicator would indicate a blue color as the pH of the mucous and other uids in the lungs averages about 7 wit a range of from about 7.45 to about 8.15.
The juices bathing the lower end of the tube 10 may be drawn into the tube, to the zone of the color-change indicator by suction means or as illustrated, in FIGURE 3, a plurality of capillary bores 40 may be provided in the tube, connecting the distal end and the absorbent paper 22. As a substitute for or in conjunction with the opening 28 and/or the capillary tubes 40, the tube may be provided with a channel extending from the distal end to the carrier 22, which channel may be tilled with a wicking substance such as absorbent paper and the like whereby body uids at the distal end of the tube may be wicked into wetting relationship with the ring type carrier 22 for the color-change indicator.
Referring to FIGURE 4 of the drawing, a further form of the improved medical-surgical tube is illustrated. In FIGURE 4 the tube 10' having an inlet or external end portion 12 is provided with an internal carrier 22', such as absorbent paper, for a color-change indicator. In FIG- URE 4 the carrier 22 is molded within the tube wall between the outer surface 24 and the inner surface 26 of the tube and one end 43 of the carrier 22 projects inwardly through the inner wall 26' to provide a wick whereby when body uids are drawn upwardly from the distal end to the zone adjacent the color-change indicator carrier 22', the indicator carrier 22' is wetted by wicking action. This form of the invention may also be provided with capillary channels 40 as indicated in FIGURE 3 of the drawing.
Referring to FIGURE S of the drawing, a further form of the present invention is illustrated, wherein the medical-surgical tube 10" having an external end portion 12" is provided with a perforated zone 44 comprising a plurality of perforations 28 which provide for communication between the inner wall 26" and the outer wall 24 of the tube 10". An absorbent band or strip 22 is mounted about the zone of perforations 44 in contact with the outer surface 24 of the tube 10" and is maintained in said stated relationship by a plastic, metal or the like sleeve 46 which may be heat sealed, cemented or frictionally maintained in its illustrated relationship on the outer surface of the tube 10". This form of the invention may also be provided with capillary or wicking channels as discussed with reference to FIGURE 3 of the drawing. In the form of the invention illustrated in FIG- UR-E 5, if the ring or band 46 is frictionally maintained in its illustrated relationship to the perforate zone 44 and the absorbent carrier 22" for the color-change indicator, the absorbent band 22" may be readily replaced after each use.
From the foregoing description, taken in consideration with the drawings, it will be seen that the present invention fully accomplishes the aims and objects hereinbefore set forth. While the invention has been particularly described with reference to the stomach tube, the invention has other uses for example, the urine of a healthy person has a known range of pH values and a doctor or technician can readily observe the pI-I condition of the urine during catheter draining thereof through the use of the present invention,
1. A medical-surgical tube having an internal end portion adapted to be inserted within a body cavity and an external end portion adapted to remain outside the body, a color-change acid-base indicator carrier means on the tube and located adjacent the outlet end portion of the tube, and means providing liquid communication between the inner wall of the tube and said indicator carrier means.
2. The invention 'clened in claim 1 wherein said indicator carrier means comprises a piece of absorbent material and an indicator absorbed thereon.
3. The invention defined in claim 2 wherein the indicator absorbed on the absorbent material comprises litmus or phenolphthalein.
4. A medical-surgical tube having Van internal end portion adapted to be inserted within a body and an external end portion adapted to remain outside the body, a color-change indicator carrier means on the tube and located adjacent the external end portion of the tube, an indicator absorbed on said carrier means, means providing liquid communication between the internal wall of the tube and the indicator absorbed on the indicator carrier means.
5. The invention defined in claim 4 wherein the indicator carrier means comprises an absorbent paper band formed within the tube and the means providing liquid communication between the internal wall of the tube and said indicator carrier means comprises a plurality of openings extending from the indicator carrier means through the inner wall of the tube in the zone of the indicator carrier means.
6. The invention defined in claim 1' wherein said indicator carrier means comprises a piece of absorbent paper one edge of which is maintained in uid contact with a portion of the inner wall of said tube.
7. The invention defined in claim 1 wherein the indicator carrier means comprises a band of absorbent material extending about a portion of the outer surface of the tube, a protective band extends over said absorbent carrier, and a zone of perforations extends between the inner surface of said absorbent carrier and the interior of said tube.
References Cited UNITED STATES PATENTS 2,567,445 9/ 1951 Parker 116-114 X 2,918,893 12/1959 Norton 116-114 3,058,472 10/ 1962 Thornton 12S- 348 3,15 5,091 1 1/ 1964 Nissenbaum 128--2 FOREIGN PATENTS 519,368 2/ 1931 Germany. 241,199 1/ 1926 Great Britain.
DALTON L. TRULUCK, Primary Examiner.