Untitled record

Nov. 8, 1938. W. B. DRAPER 2,136,236

MEANS FOR INDICATING PRESENCE AND RELATIVE AMOUNTS

DIOXIDE IN GASES FOR BREATHING

Filed April 25, 1936 4 Sheets-Sheet 1

OF CARBON

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/Cttorn.eyy

Nov. 8, 1938. w b draper 2,136,236

MEANS FOR INDICATING PRESENCE AND RELATIVE AMOUNTS

OF CARBON DIOXIDE IN GASES FOR BREATHING

Filed April 25, 1936 4 Sheets-Sheet 2

<img file="US2136236A_D0004.tif" />

Nov. 8, 1938. w b draper 2,136,236

MEANS FOR INDICATING PRESENCE AND RELATIVE AMOUNTS

OF CARBON DIOXIDE IN GASES FOR BREATHING

Filed April 25, 1936 4 Sheets-Sheet 3

<img file="US2136236A_D0005.tif" />

Nov. 8, 1938. w b draper 2,136,236

MEANS FOR INDICATING PRESENCE AND RELATIVE AMOUNTS

OF CARBON DIOXIDE IN GASES FOR BREATHING

Filed April 25, 1936 4 Sheets-Sheet 4

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Patented Nov. 8, 1938

2,136,236

UNITED STATES PATENT OFFICE

2,136,236

MMCATING presence and RELATIVE AMOUNTS OF CARBON DIOXIDE IN GASES FOR BREATHING

William B. Draper, Denver, Colo.

Application April 25, 1936, Serial No. 76,389

Claims.

My invention relates to means for indicating presence and relative amounts of carbon dioxide in gases breathed by patients, and has for its particular object to detect excess carbon dioxide in -, a gas mixture which the patient is called upon to breathe.

The breathing of mixture in which there may be excess carbon dioxide may take place in connection with gas administering devices for pro1 :> ducing anaesthesia or analgesia and in breathing enclosures such as tents and hoods wherein mix°^{f ail}’ ^{and ox}y&'en and of treated air may oe delivered to the patient.

1- foi^T^n_D»^r^^{ent technique of} administering gases 1.) foi anaesthesia or analgesia provides for breathing in a closed cycle with means in the breathing mrcuit to take carbon dioxide from the patient’s ®^^hala“^lon. there ^{belng added only suffici}ent gas in fh! ^Urf, ^t° ^{rep!ace the} elements absorbed 20 in the patients lungs and tissues. Experienc° ίίΤ¹· ^{that better res}ults are obtained with this technique than where exhaled gases go to atmosphere or to a rebreathing bag and fresh - It^{as ls c}°u^tlnually supplied in larger quantities. alwA^ h! u^t.^lmporcance that the anaesthetist always be advised whether the absorber mecha sⁿo^SthaM^U_P^{fflCientIy rem}°^{Ving carbon} dicxSI gas so that there may never be more than a permissible maximum of such gas in the material going :.3 to the patient. It is an object of my invention therefore, to provide means associated with gasmeanT ^mechanism employing absolber means, such, for example, as that shown in the >- 37 497^atfi?ⁿn°f ^{Jay A}„^Heidb™ik, Serial Number 37,497 filed August 23, 1935, for indicating with «kw? ^t0 ΐθ ^anaesthetist from time to time while the machine is administering gas for anaes^s.^la °^{r an}al&esia the condition of the gas going to the patient as regards its CO2 content.

It is a further object of my invention to provide means of freeing such gas from soda lime dust or acid content before making the test on the carbon dioxide content.

The technique of employing treated air or mixtures of air and oxygen in connection with a hood or tent also calls for breathing in a closed circuit and embodies means for removing carbon dioxide from the current of air which is caused to be withdrawn from the tent or hood at one point and returned to the tent or hood at another point after passing through soda lime absorber mechanism, and, where desired, over ice containers or other refrigerating means. It is an object of my invention to provide means associated with such a closed circulation through a tent or hood (CI. 128—203) for indicating with certainty to the anaesthetist at such times as he may desire to check on the matter the condition of the gas mixture going to the patient in this closed circuit as regards presence therein of CO2.

It is a further object of my invention to provide means whereby either the inhalation efforts of the patient or action of the operator independent of the inhalation of the patient shall cause some of the inhalation gases to by-pass and bub- 10 ble ohiough liquid in one or more containers, which liquid shall have the properties of indieating the presence of carbon dioxide and of freeing the gas prior to such indication from soda lime dust or other extraneous matter.

The full objects and advantages of my invention will appear in connection with the detailed description thereof, and its novel features are particularly pointed out in the claims

In the drawings, illustrating an application of 20 my invention in one form,—

Fig. 1 is a plan view with some parts broken away and in section of absorber mechanism attached to a gas delivering machine such as that shown in the apparatus of the above-noted Heid- 25 brink application. Fig 2 is a sectional side elevation view of said machine taken on line 2__2 of v ^g’ l· -^Fig· ^{3 is a} sectional plan view taken on line 3 3 of Fig. 2. Fig. 4 is a sectional elevation taken on line 4—4 of Fig. 1. Figs. 1, 2 and 4 30 show my improvements applied to the aforesaid Heidbnnk absorber mechanism. Fig. 5 is a side elevation view partly in section along line 5—5 of Fig 2. Fig. 6 is a similar view with more parts in section and some of the parts in different posi- 35 h°n. Fig. 7 is a view taken on line 7—7 of Fig. 6. Fig. 8 is a part perspective elevation view of an oxygen tent and the mechanism associated therewith, with my invention applied thereto. Fig 9 is a side sectional elevation view along the return 40 passageway from the oxygen tent and through a part of the valve mechanism connecting mv improvements therewith. Fig. io is a horizontal fragmentary sectional view showing the two passageways leading to and from the tent to the box 45 containing the absorber and cooling mechanism. Fig 11 is a fragmentary elevation view partly in section on an enlarged scale showing the connection of the passageway for withdrawing samples of gases from the tent.

• ^As ®^hoyⁿ· ^{in the} structure of Figs. 1 to 7 inclusive the breathing line comprises inhale side 10 and exhale side 11 from respirator 12, inhale side lu drawing through valve chamber 13 which communicates by duct 14 with a gas mixing and 55

2,136,236 delivering machine indicated diagrammatlcally at 15. The exhale passage 11 on the exhale side of the breathing circuit passes through valve chamber 16 and passageway 11 to absorber valve cham5 ber ¢8, which is provided with valve mechanism 19 controlled by handle 20 whereby the exhaled gases may be passed directly to rebreathing bag 21 or through either one or the other of absorber chambers 22 and 23 and from there through duct .,) 24 into valve chamber 13 and past valve 25. to inhale passages 10. Absorber container 26, which forms the independent material container chambers 22 and 23, is adapted to· be held in gastight relation against gasket 27 on supporting head 28 I.·, means of swing screw clamps 29, and a valve 30 in exhale valve chamber 16 controls flow of exhaled gases through chamber 16. A conical wire gauze partition 31 about valve chamber ¢8, and a similar gauze partition 32 supporting the soda •Ό lime absorber material in chambers 22 and 23 permits flow of exhaled gases through the absorber material or soda lime in said chambers when the valve mechanism 19 is set to provide for such movement of gases, which may be either oj through one alone or in part through both of chambers 22 and 23.

The above-defined mechanism is, as stated, that of the aforesaid Heidbrink application, and in and of itself forms no part of my invention, :'::i which, however, is designed for use in an anaestheting machine wherein there is a closed oreauhing circuit with means for passing the exhaled gases through soda lime or other material for removing carbon dioxide from the exhaled gases. 35 I will now describe the attachment which comprises the purifying and indicating means, forming in combination with the closed breathing circuit absorber mechanism the features of my invention. .,,

Upon the nipple 33 leading from the inhale valve chamber 13 and. between io and the inhale breathing line 10 I interpose a casing 3« which may embody a packing nut 35. The opening 36 from nipple S3 enters valve chamber 37 in casing .- 34 at cue side of valve seat partition 38, and an extension ninple 89 has its opening 40 (shown hi dotted lines in Figs. 5 and 6), leaving chamber 41 on the other side of valve seat partition o>8 and connecting with inhale tubing ¢0 in the closed - ₇ circuit breathing line. A cap 42 closes the end of chamber 31 and carries the threaded stem 43 of valve member 44 adapted to be positioned a distance greater or less from valve seat 38, or, if desired to engage said seat and close it. As shown _ in detail in Fig. 6, the threaded valve stem 43 extends through a packing nut 45 to make it gastight. .

The casing 34 is provided on its upper surface with a valve seat 46 surrounding an opening 47 CO around which is a threaded nipple 48 upon which is mounted by means of clamp nut 49 a tubular standard 50, which may be formed of any desired metal such as copper, brass or aluminum. An extension nipple 51 is secured to the end of cas(-. ing 54 away from valve stem 43, as shown in detail in Figs. 5 and 6. This member is provided with a T 52 having openings 53 and 59 extending in opposite directions with a valve seat and 3-way valve 55 between them, and upon the part 70 of the T 52 embodying the aperture 53 is securely mounted by means of a clamp nut 56 a tubular extension 57 similar to the tubular extension BO heretofore described.

Upon the tubular members 58 and 57 is secure75 ly mounted a supporting plate 58 upon which are supported a plurality of glass tubes similar to test tubes indicated at 59 and 60, there being two such test tubes shown, although it will be understood that it is within the scope of my invention to support any desired greater or less number οι 6 such test tubes as conditions of use may indicate. Within the test tubes a suitable amount of liquid is placed, as, for example, water in test tube 59 having its level indicated at G t and any suitable indicating solution with its level indicated at 62. 10 The test tubes 5S and G0 are closed at their upper ends by rubber stoppers 63 through which extend short tubes 64 opening above the liquid levels 61 and 62 and long tubes 65, which have their lower ends extended into said liquid to near the bottoms of said tubes. A rubber tube 66 connects tubular member 50 with long tube 65 in test tube 59. Similarly a rubber tube 67 connects short tube 64 in test tube 59, with long tube 65 in test tube 60, and a rubber tube 68 connects the short tube c ) 64 in test tube 60 with the tubular standaid 57.

Upon the nipple including the opening 54 on the T 52 is mounted a rubber tube 69 which is connected with a compression bulb 70 and also with a branch tube 7 i which in turn is connected ·2.> with a nipple 72. By means of a clamp nut 73 the nipple 72 and a valve seat 74 therein are connected with the exhale side of the breathing line ί t as clearly shown in Fig. 4. A valve disc 73 on valve seat 74 opens for expulsion of gas from 30 bulb 7G and closes against its inward or suction pull, and a valve disc 73 on valve seat 46 closes against expulsion from bulb 70 and opens to suction.

I will now describe the operation of my apove- _oi> described mechanism. With the 3-way valve 55 and the valve 44 in the positions of Fig. 5, communication from chamber 41 to tube 6S and bulb 70 is cut off. Also direct communication from duct 36 to duct 40 in the inhale side ί i of ,jo the breathing line is substantially restricted by valve 44. With the parts in this position the inhalation of the patient will cause a part of tne gas of inhalation to move past valve 76 through tube 50 and successively through long tubes 6-j 45 and short tubes 64 to bubble through the liquid having levels 61 and 62 successively in test tuoes 53 and SO, and thence to pass through tuoes 68 and 57 into the inhale side of the breathing line and to the patient. _ >o

This will be done at such times as the anaesthetist may desire to have a check on the possible carbon dioxide going into the inhale side of the closed breathing circuit. The bubbling of wie inhaled gas through the indicator solution 62 -.-, will indicate the amount of CO2, which may, if desired, be shown on a scale indicated generally at 80, Figs. 5 and 6. . .

When the parts are in the position of Fig. 6,, the patient cannot, of course, draw any gas on inhal- (.-0 ation through the tubes and the liquids in the test tubes and will at all times have merely normal breathing conditions for the closed breathing circuit, and the apparatus will be maintained m the position of Fig. 6 at all times excepting when c>;> the anaesthetist wishes to check on the possible CO2 in the inhalation gas. In many cases it may put too much load on the patient’s inhalation for the patient himself to draw the gas through the tubes and the solutions, and I have arranged /0 a means for accomplishing this without the intervention of the patient’s breathing and without any loss of the gases in the closed circuit breathing line. With the parts as shown in Fig.

6, if the bulb 70 is compressed the valve 76 will 75

ΙΟ

7J^aSH^g°^{mg int0 the inhale side} and the S ^{the gas eXPeIIed from the}Snf tt ^{t0 exhale side of the} breathing circuit. Upon releasing· the bulb the opposite result will take place. The valve 75 will close communication with the exhale side and the valve 6 will permit the bulb to suck gas from the inhale side and draw it through the tube connections to bubble through the liquids in the tubes whereby the operator can obtain the desired information at any time. The bulb 70 will be made large enough so ordinarily a single compression and expansion will draw enough gas through the indicating liquids to give the desired information ?^Pd’°.^ff^ourse>^{it; ls} always possible for the anaesthetist to repeat the operation as many times as he may desire.

In the form of my invention in Figs. 10 and 11 an oxygen tent 80 of usual construction is shown ?^PoI^{ted above the head of} a bed 81 by a standard 82 and a support 83 carried thereby As shown m Fig. 10 a wall 84 of the tent 80 is pro^{vldpd passages} 85 and 86 united with the no expanded couplings 87. A conditionaTre°^{X 8}V^{S provided w}ith a soda lime chamber 89 through which mixture from one end of the ent is caused to move through passageway 85 iiL^{a S}L“ii^{le motor}· not shown, the air passing ough the soda lime 90 in chamber 89 and 30 over ice or other refrigerating means not shown in chamber 9 f and back to the tent through passageway 86. Oxygen is supplied in desired amount in a well-known way from supply mechanism indicated generally by the numeral 92, the 35 oxygen entering the soda lime chamber through ^pipe. ”⁴· ^A suitable container 94 is provided below the box 88 to receive the drip from the melting ice in the ice chamber therein. The above arrangement is or may be an oxygen tent ar40 rangement, m common use, and is illustrated of means for furnishing treated air to patients by a closed circuit passing through the box or cabinet embodying the treating means. In general the arrangement is the same where a hood is em⁴⁵ Ployed m place of an oxygen tent, and in either case my invention will be applied thereto in the same manner as herein described.

As shown in Figs. 8 and 9, the passageway 85 embodies a valve housing 95 forming a valve ₅₀ chamber 96, and the lower part of the chamber 96 connects through a passageway 97 and tubing SB with tne top of the tent, as indicated at 99 in Figs. 8 and 11. This portion of valve chamber 96 is surrounded with a valve seat f 00 adapted 55 to be closed by check valve disc fOi. From chamber 96 extends a standard 102 which supports a system of indicators and connecting tubes exactly as shown in detail in Figs. 5 and 6 and heretofore described. In this form the tubing GO 7 goes directly to the bulb 70 without the intervention of a shut-off valve. The bulb 70 as in Figs. 8 and 9, connects by tubing 103 with valve casing 104 which embodies a shut-off valve 105 and includes a valve chamber 106 opening into passageway 85, valve seat 107 and valve disc 198 as shown in Fig. 9. By these means, through compression of bulb 70 gas may be drawn through tubing 98 from within the tent or hood and pass through the indicator tubes 59 and 60 and then discharge back into the circuit through valve casing ¢99 surrounding the valve chamber 106.

Various solutions may be employed as indicators in the tubes 59, 60 acting in a well-known way to give the desired indication through

2,136,236 θ ! changes in color of the solution. I have found . that superior results may be secured by using a solution of brom cresol purple in a solution fnnni-^{C1Um car}h°^nate· The calcium carbonate tn ^buffer· ^An alkaline buffer serves to regulate the pH of the solution, so that its concentration may be varied as desired accordhhnff ^working conditions, and such variations “ concentration make possible the attainment of various pH strengths with the same conofXX¹ °L^C&lt;?²· ^{moving in the} closed circuit of the anaesthetizing machine or of the oxygen tent. A practically universal solution my XPloy a seventy-five per cent saturated solution of calcium carbonate. When this strength of buffer is used one and one-half per cent of CO₂in the gases produces a reddish purple in the rise^the’ nH ^{tbe percentage of co}^ In the gases the pH of the solution falls, and with a

COs concentration of four per cent the indicator 20 becomes yellow. Although solutions of other salts may be used as a buffer, I prefer to use calcium carbonate because it is easily prepared, because it is low-pnced, because it is resistant to change on standing and because it.is relatively resistant 25 significant change by contamination with soda lime or tap water, which is a matter to be con®^ldeJ.^ed because of the possible varied operating Twa’mT X ^{Which the soIuti}°n Will be used.

-°^{USe brom creso1 purple} as the indicator 30 beeause n, gives a color change which is rapid and definite enough to be easily detected, and because its color change is over a pH range narticularly suited to regulation by variation of the buffer concentration.

The advantages of my invention will be ap- ⁵parent from the foregoing description. By means

VT ^Slmple attachment or addition to a standard gas anaesthetizing machine employing CO2 absorber means and a closed circuit to pass exhalation gases through said absorber or to *° an oxygen tent or hood through which a c’osed πΛΤρΗ re ^{gases t}I^{eated and t0} be breathed is Passed, the anaesthetist may quickly and readily at any time check on inhalation gases to deter- „ mine whether CO2 in the inhalation gases going mnm^e -^{S excess of a permi}ssible maximum. If the indication shows that there is an excess of CO2, immediate correction may be mart'· ’re·¹*^{6 CaSe} °^{f tbe gas} administering rn ^{be e}®^ected by the anaesthetist shifting the valve mechanism 19 controlling flow of exha-lation gases through the absorbing material to produce greater absorption, or, if required temporarily to throw out of operation the ab-’ Xd re^{WhiIe abS}°^{rber materiaI is} being replen- ⁵⁵ished therein and open the breathing line to ner mit exhalations to go to atmosphere or direcTto the re-breathing bag with additional supplies of fresh gas from the gas mixing machine £ tests M made where employed in connection with the ’ oxygen tent, correction may be made by addtag more oxygen and changing the soda lime in the tafttXXf t¹¹’ ^and’ “ ^desired’ by evacUS! mg the tent of its gas mixture content. _pr . re^enCe\^{by the means} herein described, danger ’° to the patient from incomplete absorption of CO2 m a closed breathing circuit and the presence of excess amounts of CO2 therein may be effectivelv and certainly avoided. ^veJy