Surgical drainage apparatus

A surgical pleural drainage apparatus for draining fluids from the body of a patient is disclosed. The apparatus includes a container with a collection chamber. A suction outlet is provided on the container which is connected to a source of negative pressure and a fluid passageway connects the suction outlet to the collection chamber. A non-liquid one-way valve is provided in the fluid passageway for allowing fluid flow only from the collection chamber to the suction outlet. An air leak indicator is also provided in the passageway to indicate a flow of gases through the passageway and optionally the qualitative quantity of that flow. Preferably, the air leak indicator includes a visible liquid trap through which any gases flow and form bubbles which are visible. The liquid trap is prefilled with glycerine or a like liquid. The amount of negative pressure applied to the collection chamber is controlled by a suction control device. An excess negative pressure relief device and a positive pressure relief device are also provided for the collection chamber. Preferably, a pressure measuring device is provided for measuring the negative pressure in the passageway and a dynamic pressure measuring device is provided for measuring the pressure changes in the collecting chamber during respiration.

FIELD OF THE INVENTION 
The present invention relates generally to surgical drainage devices which 
are used in draining fluids from the body, e.g. the pleural cavity. 
BACKGROUND OF THE INVENTION 
It is essential for normal breathing that the space within the pleural 
cavity surrounding the lungs be free of liquid and be subject to negative 
pressure so as to draw the lungs outwardly to fill this pleural cavity in 
order to permit optimal breathing. Any invasion of the pleural cavity such 
as caused by lung surgery of foreign objects which pierce the rib cage or 
such as occur, for example, when the patient has pleurisy, generates 
fluids in the pleural cavity which tend to obstruct normal breathing. It 
is thus necessary to provide a device which can remove these fluids from 
the pleural cavity and at the same time insure that the desired degree of 
negative pressure is maintained within the pleural cavity. 
One of the basic types of apparatus which has been used for this purpose is 
shown, for example, in U.S. Pat. Nos. 3,363,626 and 3,363,627. This 
apparatus is known as an underwater drainage apparatus and provides three 
chambers, one chamber comprising a collection chamber for collecting the 
fluids drained from the pleural cavity through a thoracotomy tube, a 
second chamber known as an underwater seal chamber which protects the 
pleural cavity from being subject to atmospheric pressure, and a third 
chamber known as a pressure manometer chamber which serves to regulate the 
degree of negative pressure within the pleural cavity. This type of 
apparatus has been highly successful in both removing fluids from the 
pleural cavity and in maintaining the desired degree of negativity within 
the pleural cavity. 
However, an apparatus such as disclosed in the patents referred to above 
requires prefilling of the underwater seal chamber with water as well as 
prefilling of the pressure manometer chamber to the desired level to 
maintain the desired degree of negativity within the pleural cavity. It is 
obvious that it would desirable to eliminate the need for filling the 
underwater seal and manometer chambers, particularly in emergency 
situations but also in general use. This is because the less the user of 
the apparatus has to do with the operation the less likely it is that 
something will be done improperly, i.e. the greater the active 
participation the greater the chance for human error. For this reason, 
drainage devices have been developed which do not require a filling of the 
underwater seal chamber. Examples of such devices are disclosed in U.S. 
Pat. Nos. 4,015,603 and 4,396,386. However, an underwater seal must still 
be formed using the liquids drained from the body of the patient. 
The latter patent referred to above also discloses a manually adjustable 
control valve to regulate the negative pressure applied in the collection 
chamber and a bellows for indicating the amount of negative pressure 
within the collection chamber. A means for controlling the negative 
pressure in a collection chamber is also disclosed in U.S. Pat. No. 
4,372,336. The means disclosed is a diaphragm which is movable into 
position on the suction outlet of the device whenever the applied suction 
is too great. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a surgical pleural drainage 
apparatus for draining fluids from the body of a patient is provided. The 
apparatus includes a container with a collection chamber formed therein. 
The collection chamber is used to collect fluids received through a fluid 
inlet in the container from the body of the patient. A connection means is 
provided for connecting the collection chamber to a source of negative 
pressure so that a negative pressure or suction is created within the 
collection chamber to draw fluids into the collection chamber through the 
fluid inlet. The connecting means includes a suction outlet mounted on the 
container and a fluid passageway which connects the suction outlet with 
the collection chamber. A non-liquid passageway one-way valve means is 
provided in the passageway for allowing fluid flow only from the 
collection chamber to the suction outlet. An air leak indicating means is 
also provided in the passageway for indicating the directional flow of any 
gases through the passageway and optionally the qualitative quantity of 
these gases. A suction control means is further provided in the passageway 
for controlling the amount of negative pressure applied to the collection 
chamber. This control means holds the pressure applied to the collection 
chamber at a relative constant despite changes in wall suction varying 
from 30 mmHg to 500 mmHg. 
In the preferred embodiment of the present invention, the air leak 
indicating means includes a liquid trap which is visible through the 
container. Thus as any gases flow therethrough, bubbles are formed which 
serve as visible indicators of such a flow and of a patient air leak. An 
excess negative relief means for relieving excess negative pressure in the 
collection chamber and a positive pressure relief means for relieving 
positive pressure in the collection chamber are also provided. Preferably, 
the excess negative pressure relief means, when activated, permits the 
flow of air at atmospheric pressure through a filter of about 0.45 microns 
into the collection chamber until the pressure in the collection chamber 
is approximately -10 cmH.sub.2 O, at which pressure the negative pressure 
relief valve is automatically inactivated out of the control of the 
operator. The negative pressure in the collection chamber must be greater 
than -10 cmH.sub.2 O before the negativity relief valve will allow air 
flow into the collection chamber. 
In the preferred embodiment, a pressure measuring means for measuring the 
negative pressure in the passageway is also provided. The pressure 
measuring means includes a vertically disposed straight bore having two 
adjoining tapered slots. A ball is disposed in the bore. The ball rises in 
the bore to a position dependent on value of the source of negative 
pressure. 
In one preferred embodiment, the control means includes a fine pressure 
adjusting means including a first chamber having a resiliently biased fine 
one-way valve disposed therein. The first chamber is divided by the valve 
into a vent side which is vented to atmosphere and a suction side which 
forms a portion of the passageway. A gross pressure adjusting means 
including a second chamber is provided which has a resiliently biased 
gross one-way valve disposed therein. This gross one-way valve divides the 
second chamber into a vent side which is vented to atmosphere and a 
suction side forming a portion of the passageway downstream of the suction 
side of the first chamber. The suction side of the second chamber is also 
connected to the suction side of the first chamber through a restricted 
opening. In this manner, fluid flow is allowed from the vent side to the 
suction side of the second chamber only when the negative pressure in the 
suction side exceeds a value somewhat greater than the desired value of 
negative pressure in the passageway. Preferably, the suction side of the 
second chamber is connected directly to the suction outlet and a 
restrictor is also provided in the suction outlet so that the negative 
pressure applied by the source of suction to the suction side of the 
second chamber is reduced by the restrictor. 
In an alternative embodiment of the present invention, the control means 
includes a suction varying means for varying the amount of negative 
pressure applied to the collection chamber relative to the negative 
pressure applied at the suction outlet. The suction varying means includes 
a plurality of resiliently biased valve means arranged in a series with 
the outlet of one valve means connected to the inlet of the next valve 
means. The initial inlet of the first valve means in the series is vented 
to atmosphere while the last outlet of the valve means in the series is 
connected to the suction outlet. A passage is also provided from each 
respective outlet to the suction outlet through a valve selector which can 
be adjusted to fluidly connect one of the respective outlets with the 
suction outlet. In this manner, depending on the outlet selected by the 
selector, the rate of flow of bleed air to the suction outlet and hence 
the negative pressure at the suction outlet is adjusted so that the amount 
of negative pressure which is applied to the collection chamber is 
adjusted. 
According to the preferred embodiment, a dynamic pressure measuring means 
is also provided for measuring pressure changes in the collection chamber 
and hence the changes in pressure in the collection chamber as the patient 
breathes. Preferably, the dynamic pressure measuring means includes a 
bellows whose interior region is fluidly connected to the collection 
chamber and whose exterior region is fluidly connected to the passageway. 
Other features and advantages of the invention are stated in or apparent 
from a detailed description of presently preferred embodiments of the 
invention found hereinbelow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference now to the drawings in which like numerals represent like 
elements throughout the views, a surgical pleural drainage apparatus 10 is 
depicted in FIGS. 1 and 2. Drainage apparatus 10 includes a container 12 
in which a collection chamber 14 is provided. As shown, collection chamber 
14 is divided into three connected compartments so that the liquids 
collected therein are easily measured by suitable indicia 178 provided on 
the front of the container 12. Located immediately above the first 
compartment is a fluid inlet 16 which extends through collection chamber 
14 to the top of container 12. Fluid inlet 16 is suitably connected to the 
patient by a thoracotomy tube (not shown) or the like to conduct fluids 
drained from the patient into collection chamber 14. 
Container 12 also includes a suction outlet 18 which is suitably connected 
to a source of suction or negative pressure. As shown, the base of suction 
outlet 18 includes a restricted bore 20. Suction outlet 18 is fluidly 
connected to collection chamber 14 via a passageway 22 which includes a 
non-fluid passageway one-way valve means 24, an air leak indicating means 
26, and a control means 28. 
As shown best in FIG. 2, container 12 is divided into collection chamber 14 
and an upper chamber 30 by an interior wall 32. Passageway 22 begins at 
interior wall 32 where a suction inlet 34 is located. Connected to suction 
inlet 34 is a short passage 36 which terminates in a tell-tale chamber 38. 
Should any liquids inadvertently be withdrawn through suction inlet 34, 
the liquids accumulate in the bottom of tell-tale chamber 38 and serve as 
a visible indication of a malfunction of drainage apparatus 10. 
Tell-tale chamber 38 is fluidly connected to a valve chamber 40 through a 
bore 42 as shown. Valve chamber 40 is divided into an inlet side 44 and an 
outlet side 46 by a wall 48. One-way valve means 24 fluidly connects inlet 
side 44 to outlet side 46. One-way valve means 24 includes a valve seat 
member 50 in which two umbrella valves 52 and 54 are arranged in series. 
Alternatively, one-way valve means 24 could include appropriate ball and 
spring one-way valves. The purpose of one-way valve means 24 is to allow 
fluid flow in passageway 22 only from suction inlet 34 to suction outlet 
18 and to prevent any reverse fluid flow in passageway 22. 
A short passage 56 is used to fluidly connect outlet side 46 of valve 
chamber 40 with air leak indicating means 26. As shown, short passage 56 
terminates in a vertically disposed tube 60 having a bottom outlet 62. 
Tube 60 is disposed in an air leak chamber 64 having a concave bottom 66 
which is adjacent outlet 62. A small volume of a suitable liquid 68, such 
as glycerine, is provided in air leak chamber 64 to a height slightly 
above outlet 62 in tube 60. Liquid 68 preferably has a high vapor pressure 
so that liquid 68 does not readily evaporate. 
Air leak chamber 64 is fluidly connected to a passage chamber 70 by a short 
passage 72. As shown, one end of short passage 72 is adjacent tube 60 and 
is surrounded by a collar 74 which is attached to tube 60. Collar 74 is 
spaced slightly from the end of short passage 72 such that an air gap is 
provided for fluid flow. It should be appreciated that no matter how 
drainage apparatus 10 is tipped, liquid 68 cannot enter and pass through 
short passage 72. It should further be appreciated that no matter how 
drainage apparatus 10 is tipped, liquid 68 cannot enter the end of short 
passage 56 provided in tube 60 either. 
A sealed tube 76 is also provided between the top of tube 60 and the 
exterior of container 12. Sealed tube 76 is sealed by a rubber diaphragm 
(not shown) so that no fluids pass through seal tube 76. However, should 
it be desired to add any additional liquid 68 to air leak chamber 64, a 
hypodermic needle can be temporarily extended through sealed tube 76 to 
supply the desired additional quantity of liquid 68. 
Passage chamber 70 includes an exit bore 80 which opens into an elongate 
passage 82 along the top of container 12. Elongate passage 82 fluidly 
connects passage chamber 70 with control means 28. 
Control means 28 includes a fine or primary control chamber 84 which is 
separated into a suction side 86 and a vent side 88 by an umbrella valve 
90. As shown, suction side 86 is connected to elongate passage 82 by a 
short passage 92. Vent side 88 is connected to a vent chamber 94 by an 
elongate passage 96. Vent chamber 94 includes a slot 98 in the back wall 
of container 12 by which vent chamber 94 is maintained at substantially 
atmospheric pressure. 
Located in a vertical section of elongate passage 96 is a pressure 
measuring means 100. Pressure measuring means 100 includes a member 102 
having an elongate bore 104 therein. Located at the bottom of bore 104 is 
a restricted opening 106 which has a much smaller diameter than bore 104. 
Located at the top of bore 104 is an opening 108 which has a diameter 
about the same as bore 104 at that point. As shown in FIG. 2, bore 104 is 
provided with pair of opposed, tapered slots 105 extending along and open 
to bore 104. Disposed within bore 104 is a ball 110. Ball 110 rises in 
bore 104 depending upon the volume of bleed air conducted through bore 
104. 
Disposed adjacent to fine or primary control chamber 84 is a gross or 
secondary control chamber 112. Secondary control chamber 112 is divided 
into a suction side 114 and a vent side 116 by an adjustable umbrella 
valve 118. As shown, vent side 116 includes three openings 120 by which 
vent side 116 is vented to vent chamber 96 and hence to atmosphere. A 
restricted opening 122 fluidly connects suction side 114 with suction side 
86 of primary control chamber 84. Suction side 114 is also connected to 
suction outlet 18 and restricted bore 20 through opening 124. It should be 
appreciated that screw 126 which attaches adjustable umbrella valve 118 to 
the dividing wall in secondary control chamber 112 is turned to vary the 
pressure differential necessary for adjustable umbrella valve 118 to open. 
Use of this adjusting feature will described subsequently. 
Drainage apparatus 10 is also provided with an excess negative pressure 
relief means 130 which is shown in greater detail in FIGS. 6, 7 and 8. 
Excess negative pressure relief means 130 is used to relieve excess 
negativity which can occur in collection chamber 14. Preferably, excess 
pressure relief means 130 is actuated by a push button 134. Excess 
negative pressure relief means 130 is connected to collection chamber 14 
through a passage 136 as shown. Details of a suitable excess negative 
pressure relief means 130 are discussed subsequently. By actuation of push 
button 134, atmospheric air is permitted to flow into collection chamber 
14 to relieve any excess negativity therein. 
Drainage apparatus 10 is further provided with a positive pressure relief 
means 140. Positive pressure relief means 140 is used to relieve any 
positive pressures which are inadvertenly created in collection chamber 14 
and hence in elongate passage 82. As shown in FIG. 2, positive pressure 
relief means 140 includes a passage 142 which extends from elongate 
passage 82 to vent chamber 94 and in which an umbrella valve 144 is 
disposed. Umbrella valve 144 is designed to open only when a predetermined 
positive pressure exists in elongate passage 82 so that this undesired 
positive pressure is vented to atmosphere through vent chamber 94. 
Otherwise, umbrella valve 144 prevents any reverse flow of atmospheric air 
into elongate passage 82. 
A dynamic pressure measuring means 150 is also provided in drainage 
apparatus 10 for measuring the changes in pressure in collection chamber 
14 as the patient breathes. Dynamic pressure measuring means 150 includes 
a bellows 152 disposed in a bellows chamber 154. Bellows chamber 154 is 
fluidly connected to elongate passage 82 by a passage 156. As shown in 
FIG. 2, bellows 152 is suspended from a horizontal wall 158 having an 
opening 160 therein. At the bottom of bellows 152 is a small weight 162 
which normally rest against a stop 164 prior to the actuation of drainage 
apparatus 10. 
As shown in FIG. 1, bellows 152 also includes an indicator 166 and indicia 
168 located adjacent indicator 166 on face 170 of container 12. The 
instantaneous pressure in collection chamber 12 is transferred to the 
interior of bellows 152 through openings 172 in tell-tale chambers 174. 
Should container 12 be tipped such that liquids enter tell-tale chambers 
174, some of the liquids are left in tell-tale chambers 174 so that a 
malfunction of drainage apparatus 10 is indicated thereby. It should be 
appreciated that the interior of bellows 152 is fluidly connected to 
collection chamber 14 and the instantaneous changes in pressures which 
occur therein as the patient breathes. The exterior of bellows 152 is also 
fluidly connected to collection chamber 14 but only through a tortuous 
path including flow indicating means 26 and passageway one-way valve means 
24. For that reason, the change in pressure which occurs in passage 158 
and hence on the exterior of bellows 152 is not instantaneous but is 
delayed sufficiently to allow bellows 152 to expand or contract with the 
increases or decreases of pressure in collection chamber 14 as the patient 
breathes. Thus, the movement of indicator 166 relative to indicia 168 
provides an easy determination of the changes in pressure in collection 
chamber 14 as the patient breathes. Bellows 152 also indicates excessive 
negative pressure which may be due to striping or the patient gasping for 
breath. 
As shown in FIG. 1, face 170 of drainage apparatus 10 includes a number of 
transparent sections so that the operation of drainage apparatus 10 can be 
observed. Thus, clear section 176 is provided over the three columns 
making up collection chamber 14 so that the filling of collection chamber 
14 with liquids is observed. For this reason, indicia 178 is provided 
adjacent to the columns of collection chamber 14 to allow the amount of 
liquids collected to be measured. In the same manner, a clear section 180 
is provided over indicator 166 on bellows 152 so that the movement of 
indicator 166 is seen. As indicated previously, indicia 168 is provided 
adjacent clear section 180. 
A clear section 182 is also provided in face 170 in front of flow 
indicating means 26. The bubbling of gases through liquid 68 is then 
easily seen through clear section 182. Finally, a clear section 184 is 
also provided in front of pressure measuring means 100 so that the 
movement of ball 110 in bore 104 is observed. Indicia 186 is located 
adjacent clear section 184 so that the pressure in collection chamber 14 
is determined by the movement of ball 110. Conveniently, a band 188 of 
indicia 186 is designated which is the desired location of ball 110 and 
indicates the proper suction or negative pressure in collection chamber 
14. 
In operation, drainage apparatus 10 functions in the following manner. 
Initially, it is noted that drainage apparatus 10 is provided in a sterile 
package and conveniently includes a hose (not shown) attached to suction 
outlet 18 which is connected to a source of suction and a separate 
thoracotomy hose (not shown) attached to fluid inlet 16 which is fluidly 
connected to the pleural cavity of the patient to be drained. In addition, 
container 12 is provided with liquid 68 already located in seal chamber 
64. As discussed above, seal chamber 64 is constructed such that liquid 68 
cannot be spilled therefrom during transport and storage of container 12, 
no matter how container 12 is oriented or shifted. In addition, screw 126 
has been adjusted during manufacture to bias adjustable umbrella valve 118 
so that a predetermined negative pressure in suction side 114 is necessary 
to open adjustable umbrella valve 118 to allow fluid flow from the 
atmosphere to suction side 114. 
After suction outlet 18 is connected to a source of suction or negative 
pressure and fluid inlet 16 is connected to the pleural cavity of the 
patient, a negative pressure is created in collection chamber 14. As shown 
in FIG. 2, liquids and gases from the patient are drawn into collection 
chamber 14 through tube 16. The negative pressure created in collection 
chamber 14 is provided by the withdrawal of gases from suction inlet 34 
through passageway 22 to suction outlet 18. This flow of gases is 
indicated generally by arrowed line 190. Thus, gases flow from collection 
chamber 114 through short passage 36 to tell-tale chamber 38. If container 
12 were tipped so that liquids were drawn into short passage 36, any 
liquids passing further than passage 36 are indicated by an accumulation 
of the liquids at the bottom of tell-tale chamber 38. 
The withdrawn gases are next passed through one-way valve means 24 which 
prevents any reverse flow of fluids so that an inadvertent loss of 
negative pressure at suction outlet 18 does not cause collection chamber 
14 to immediately lose the negative pressure present therein. The 
withdrawn gases are next passed through short passage 56 to flow 
indicating means 26. As the gases enter tube 60, the gases are drawn 
though liquid 68 causing bubbling therein before passing through short 
passage 72. As shown in FIG. 1, the bubbling of the gases through liquid 
68 is easily seen from the front of drainage apparatus 10 through clear 
section 182. No bubbling through liquid 68 indicates a proper operation of 
drainage apparatus 10. However, continuous bubbling through liquid 68 
indicates either an air leak in the connections in container 12 or an air 
leak in the pleural cavity of the patient. In either event, persistent 
bubbling acts as an indicator that something is wrong and needs to be 
corrected. If for some reason liquid 68 is not at a sufficient height in 
air leak chamber 64, additional liquid is injected through seal tube 76. 
From short passage 72, the withdrawn gases pass through elongate passage 82 
to suction side 86 of primary control chamber 84 which forms part of 
control means 28. The suction or negative pressure created in suction side 
86 causes umbrella valve 90 to open when the suction exceeds a 
predetermined value. For example, umbrella valve 90 can be selected so as 
to open when the suction in suction side 86 is approximately -20 
centimeters of water. When the suction is greater than -20 centimeters of 
water, air is withdrawn from atmosphere through slot 98 in vent chamber 94 
as indicated by arrow line 192. This air is further withdrawn through bore 
104 and pressure measuring means 100 to elongate passage 96, vent side 88, 
and finally around umbrella valve 90 to suction side 86. As air is drawn 
through bore 104, ball 110 is caused to rise in bore 104 to a distance 
which is proportional to the volume of air flow through bore 104. This 
rising of ball 110 is due to the increasing size of slots 105 in bore 104. 
The position of ball 110 is seen through clear section 184 on face 170 of 
container 12. By use of indicia 186, the suction or negative pressure in 
suction side 86 and in collection chamber 14 is measured by the position 
of ball 110. Where the value of the suction applied to suction outlet 18 
is variable, this suction source is varied until ball 110 rises to a 
position adjacent band 188 so that the proper suction in collection 
chamber 14 is indicated. 
From suction side 86 of primary control chamber 84, the withdrawn gases 
pass through restricted opening 122 into suction side 114 of secondary 
control chamber 112. From suction side 114, the gases pass through 
restricted bore 20 to suction outlet 18 and from there to the source of 
negative pressure. The suction or negative pressure exerted by the source 
of negative pressure is exerted directly on suction side 114 of secondary 
control chamber 112. If this negative pressure is too great, adjustable 
umbrella valve 118 opens to allow atmospheric air to bleed from vent 
chamber 94 into vent side 116 of secondary control chamber 112 and thence 
past umbrella valve 118 to suction side 114. 
The pressure differential necessary to open adjustable valve 118 is 
adjustable by advancing or withdrawing screw 126 from the mounting wall. 
As mentioned above, the adjustment of screw 126 is preferably done at 
manufacture so that umbrella valve 118 opens at a predetermined pressure. 
For example, umbrella valve 118 can be adjusted to open where the suction 
created in suction side 114 is somewhat greater than -20 centimeters of 
water, -40 centimeters of water, or -60 centimeters of water. In any 
event, when umbrella valve 118 opens, the flow of atmospheric air to 
suction side 114 as indicated by arrow lines 194 is relatively 
unrestricted until this flow is throttled down by restricted bore 20 and 
opening 124. Thus, the flow of atmospheric air to suction side 114 is 
sufficient to significantly lower the suction or negative pressure created 
there to a value slightly greater than that desired in collection chamber 
14. 
It should be appreciated that the suction side 114 maintains a negative 
pressure in suction side 86 of primary control chamber 84 as well. This 
negative pressure is preferably sufficient to open umbrella valve 90 so 
that atmospheric air is withdrawn from vent chamber 94 through pressure 
measuring means 100. As mentioned above, umbrella valve 90 is designed to 
open so as to maintain the desired negative pressure in collection chamber 
14. The additional flow of atmospheric air around umbrella valve 90 is 
sufficient to lower the negative pressure applied from suction side 114 of 
secondary control chamber 112 to the desired negative pressure for 
collection chamber 14. 
After operation has commenced, a relatively constant negative pressure is 
created in collection chamber 14 and in elongate passage 82. As mentioned 
above, the interior of bellows 152 is connected directly to collection 
chamber 14 while the exterior of bellows 152 is connected directly to 
elongate passage 22. When the patient breathes, slight changes in pressure 
occur in collection chamber 14. As this occurs, bellows 152 and indicator 
166 move to indicate this breathing. By use of indicia 168 and the 
movement of indicator 166, the respiratory cycle pressures of the patient 
are determined. 
If excess negative pressure is exerted in collection chamber 14, such as by 
milking of the thoracotomy tube or other extraneous manipulations, the 
excess negative pressure is indicated by bellows 152 and is relieved by 
use of excess pressure relief means 130. To accomplish this, push button 
134 is depressed to allow the flow of atmospheric air as indicated by 
arrow line 196 into collection chamber 14 through passage 136. Push button 
134 is depressed until the negative pressure in collection chamber 114 is 
returned to the proper values at which time excess negative pressure 
relief means 130 automatically ceases to function as explained 
subsequently. 
Where an undesired positive pressure is advertently applied to collection 
chamber 14 and hence elongate passage 82, this positive pressure is 
automatically relieved by use of positive pressure relief means 140. Thus, 
the positive pressure in collection chamber 14 and elongate passage 82 
causes umbrella valve 144 to open so that gases in collection chamber 14 
pass to atmosphere through slot 98 as indicated by dotted line 198. 
Depicted in FIG. 3 is an alternative embodiment of a secondary control 
chamber 200 which can be used in place of secondary control chamber 112 in 
drainage apparatus 10. In this embodiment, secondary control chamber 200 
includes a suction side 202 which corresponds to suction side 114 of 
secondary control chamber 112 and includes an opening 124' connected to 
suction outlet 18 and a restricted opening 122' connected to suction side 
86 of primary control chamber 84. Instead of an adjustable umbrella valve 
118 as with secondary control chamber 112, secondary control chamber 200 
is provided with a valve selector 204. Valve selector 204 includes a 
circular valve member 206 which is shown in greater detail in FIG. 4. 
Valve member 206 includes an arcuate slot 208 therethrough. Attached at 
the center of valve 206 is a stem 210 which extends throuhg secondary 
control chamber 200 and the top of container 12 to terminate in a handle 
212. 
Located beneath valve selector 204 is a series valve member 214. Series 
valve member 214 is divided into three chambers 216, 218 and 220. Mounted 
in each chamber 216, 218 and 220 is a resiliently biased umbrella valve 
222, 224, and 226, respectively. Each chamber 216, 218, and 220 also 
includes a passage 228, 230, and 232, respectively, which terminates at 
one side of valve member 206. As shown best in FIG. 4, passages 228, 230 
and 232 are equally spaced around the center of valve member 206 at a 
distance from the center of valve 206 equal to the distance of arcuate 
slot 208 from the center of valve member 206. It should be appreciated 
that valve member 206 is rotatable by handle 212 to position arcuate slot 
208 over one of passages 228, 230 or 232. In addition, arcuate slot 28 is 
of such a length that at least one of passages 228, 230 or 232 lies 
underneath arcuate slot 208 at all times. 
Series valve member 214 includes an inlet end 234 which is suitably vented 
to atmosphere such as by being vented to vent chamber 94 in container 12. 
Preferably, umbrella valves 222, 224, and 226 are substantially identical 
and open when a predetermined pressure differential exists across a 
respective umbrella valve 222, 224 or 226. This predetermined pressure 
differential is chosen at a convenient value, such as -20 centimeters of 
water. Thus, umbrella valve 222 only opens when the pressure in chamber 
216 is less than -20 centimeters of water. Because umbrella valves 222, 
224 and 226 are in series, umbrella valve 224 only opens when the pressure 
in chamber 218 is -20 centimeters of water less than the pressure in 
chamber 216. Thus, umbrella valve 224 only opens after umbrella valve 222 
is opened and the pressure in chamber 218 is -40 centimeters of water. In 
the same manner, umbrella valve 226 opens only when the pressure in 
chamber 220 is -60 centimeters of water. 
In operation, secondary control chamber 200 functions in the following 
manner when used in place of secondary control chamber 112 in drainage 
apparatus 10. Initially, it is determined what value of negative pressure 
is desired in collection chamber 1. Once this is determined, handle 212 is 
rotated by the user to rotate arcuate slot 208 of valve member 206 over a 
respective one of passages 228, 230 or 232. Preferably, some indicia (not 
shown) is provided on the top of container 12 to indicate which passage 
228, 230 or 232 is connected to suction side 202 when handle 212 is at a 
particular position. 
Where passage 228 is connected to suction side 202 by movement of valve 
206, the value of negative pressure created in suction side 202 is equal 
to approximately -20 centimeters of water assuming the source of suction 
is greater than -20 centimeters of water. This will cause a slightly 
reduced pressure in collection chamber 14 as the pressure in collection 
chamber 14 will be somewhat further reduced by the bleeding of air through 
primary control chamber 84. If it is desired to increase the negative 
pressure in collection chamber 14, handle 212 is rotated to a position 
where chamber 218 is connected to suction side 202. This will cause the 
pressure in suction side 202 to increase to -40 centimeters of water and 
the negative pressure created in collection chamber 14 to correspondingly 
rise. Finally, the selection of passage 232 causes the negative pressure 
in suction side 202 to increase to -60 centimeters of water and the 
negative pressure in collection chamber 14 to also change accordingly. 
It should be appreciated that due to the construction of arcuate slot 208, 
there is no position which valve selector 204 can be rotated to where none 
of passages 228, 230 or 232 is connected to suction side 202. The design 
of arcuate slot 208 in this manner is to prevent valve selector 204 from 
ever being moved to a position where no atmospheric air is bled into 
suction side 202 so that the full force of the source of negative pressure 
is applied to primary control chamber 84 and hence to collection chamber 
14. 
Depicted in FIG. 5 is an alternative embodiment of a drainage apparatus 300 
which is broadly similar to drainage apparatus 10. Drainage apparatus 300 
includes a container 302 in which a collection chamber 304 is located. A 
fluid inlet 306 is provided into chamber 304 and a suction outlet 308 is 
also provided in communication with collection chamber 304. Suction outlet 
308 is connected to collection chamber 304 by a passageway 310 which 
includes a non-fluid passageway one-way valve means 312, an air leak 
indicating means 314, and a suction control means 316. 
Drainage apparatus 300 also includes an upper chamber 318 which is 
separated from collection chamber 304 by an interior wall 320. A suction 
inlet 322 is provided in interior wall 320 which is connected by a short 
passage 324 to a tell-tale chamber 326. Tell-tale chamber 326 is fluidly 
connected to one-way valve means 312 which is located in a valve chamber 
328. One-way valve means 312 is substantially the same as one-way valve 
means 24 of drainage apparatus 10 described above so that only flow 
upwards through one-way valve means 312 is allowed. A short passage 330 
connects valve chamber 328 to air leak indicating means 314. 
Air leak indicating means 314 functions in a similar manner to flow 
indicating means 26 of drainage apparatus 10. However, air leak indicating 
means 314 is somewhat differently constructed. As shown in FIG. 5, air 
leak indicating means 314 includes a chamber 332 having a central wall 334 
extending downwardly through the center thereof to divide chamber 332 into 
an inlet side 336 and outlet side 338. As the bottom of central wall 334 
is an aperture 340 which provides fluid communication between inlet side 
336 and outlet side 338. Normally, the bottom of chamber 332 contains a 
liquid 342 which covers aperture 340. 
As shown, short passage 330 extends from valve chamber 328 to a central 
portion of inlet side 336. Similarly, a short passage 344 extends from a 
central portion of outlet side 338 to elongate passage 346. By extending 
centrally of inlet side 336 and outlet side 338, respective short passages 
330 and 344 do not allow liquid 342 to enter therein no matter how 
drainage apparatus 300 is tipped. In other words, the ends of short 
passages 330 and 344 inside of air leak indicating means 314 extend into 
respective inlet side 336 and outlet side 338 so as to be beyond the fluid 
level no matter in which direction drainage apparatus 300 is tipped 
(sideways, upside down etc.) as may occur during shipping. It should also 
be appreciated that outlet side 338 is provided with baffle plates 348 and 
350 so that gases bubbling in liquid 342 through aperture 340 do not carry 
liquid into short passage 344. As with air leak indicating means 26 of 
drainage apparatus 10, air leak indicating means 314 is similarly viewable 
from the outside of drainage apparatus 300 so that the bubbling of air 
through aperture 340 serves as a visible indication of flow therethrough. 
Elongate passage 346 is fluid connected to a dynamic pressure measuring 
means 352 is substantially the same as dynamic presure measuring means 150 
of drainage apparatus 10 and thus will not be described further. Elongate 
passage 346 also finally fluidly connects to suction outlet 308 which is 
operably associated with control means 316 and a pressure measuring means 
354. Pressure measuring means 354 is substantially similar to pressure 
measuring means 100 of drainage apparatus 10 and will not be described 
further. 
Control means 316 is disposed in a control chamber 356 which is vented to 
atmosphere by an aperture 358. Control means 316 includes a biased valve 
means 360 as shown. Biased valve means 360 includes a valve body 362 
having a spring 364 disposed therein adjacent a valve outlet 366. 
Threadably received in the other end of valve body 362 is a valve seat 368 
having a bore 370 therethrough. As shown spring 364 seats a ball 372 
against valve seat 368. 
In operation, control means 316 functions in the following manner. With 
suction outlet 308 connected to a predetermined constant source of 
negative pressure, this negative pressure is exerted on biased valve means 
360 through valve outlet 366. This causes ball 372 to be moved against the 
force of spring 364 away from valve seat 368. In this position, 
atmospheric air is admitted through biased valve means 360 from aperture 
358 directly to suction outlet 308. As there is some resistance to flow 
through biased outlet 360, a portion of the suction exerted on suction 
outlet 308 is not compensated for by the flow of atmospheric air through 
biased valve means 360. This portion of the suction is then conducted 
through passageway 310 to collection chamber 304. 
By an appropriate design of the resiliency of spring 364 and the location 
of valve seat 368 relative to spring 364, the portion of the suction 
applied to collection chamber 304 can be maintained relatively constant. 
Preferably, the adjustment of the location of valve seat 368 relative to 
spring 364 is performed at the factory and is easily accomplished by 
threadably adjusting valve seat 364 formed or backward relative to valve 
body 362. If desired, a control means including two biased valve means 
connected in series and including a restricted opening similar to control 
means 28 can be used. 
Drainage apparatus 300 is also provided with a positive pressure relief 
valve means 374. Positive pressure relief valve means 374 is similar in 
construction to positive pressure relief valve means 140 of drainage 
apparatus 10. Positive pressure relief valve means 374 is connected to 
collection chamber 304 through passageway 310. In particular, positive 
pressure relief valve means 374 is disposed in a chamber 376 adjacent 
control chamber 356. Chamber 276 is in fluid communiction with atmosphere 
through an aperture 378 and aperture 358. Thus, where a positive pressure 
exists in collection chamber 304 (for example, above 0.5 cmH.sub.2 O), 
this pressure is conducted through passageway 310 and is automatically 
relieved through positive pressure relief valve means 374 to atmosphere. 
However, it should be appreciated that any failure of positive pressure 
relief valve means 374 does not destroy the opeation of drainage 
apparatus 300 as any air leaking through positive pressure relief valve 
means 374 is prevented from reaching collection chamber 304 by one-way 
valve means 312. Instead, any air which might leak past positive pressure 
relief valve means 374 is withdrawn through suction outlet 308 and due to 
the operation of control means 316 this leaking air should not affect the 
suction applied to collection chamber 304. 
Drainage apparatus 300 also includes an excess negative pressure relief 
means 380 which is similarly constructed to excess negative pressure 
relief means 130 of drainage apparatus 10. In this embodiment, excess 
negative pressure relief means 380 is disposed in tell tale chamber 326 so 
that excess negative pressure relief means 380 is exposed to the negative 
pressure in collection chamber 304 through short passage 324. 
The details of the construction of excess negative pressure relief means 
380 are shown in greater detail in FIGS. 6, 7, and 8. As shown in these 
figures, excess negative relief means 380 includes a valve body 382 having 
a seating surface 384. Located adjacent seating surface 384 is a plunger 
386 having an O-ring 388 disposed along the surface of plunger 386 
adjacent seating surface 384. Plunger 386 also includes a stem 390 which 
extends through an aperture 392 in seating surface 384. Attached to stem 
390 is a push button 394. 
As shown, plunger 386 is spring biased so that O-ring 388 contacts seating 
surface 384 by a spring 396. Spring 396 presses against a member 398 
attached to the lower end of valve body 382. As shown, member 398 has an 
aperture 400 therein. With this construction, push button 394 is normally 
biased by spring 396 into the position where O-ring 388 contacts seating 
surface 384 and any flow through valve body 382 is prevented. 
Also attached to the bottom of valve body 382 is a one way valve means 402. 
One-way valve means 402 includes a valve body 404 having a central 
aperture 406 and four apertures 408 located therein. The top of valve body 
404 is spaced from the bottom of member 398 to provide for the flow of air 
between apertures 408 and aperture 400. 
One-way valve means 402 also includes an umbrella valve 410 whose stem 412 
is received in central aperture 406 as shown in FIG. 6. The umbrella 
portion of umbrella valve 410 then extends out over apertures 408. Located 
below umbrella valve 410 is a filter assembly 414 (FIG. 7) including a 
filter cover 416, a filter 418, and a filter bottom 420. As shown in FIG. 
8, filter cover 416 is preferably formed of a spiral and spoked pattern to 
allow a maximum flow of air through filter 418. Filter bottom 420 also 
includes an aperture 422 therein. 
In operation, excess negative pressure relief means 380 functions in the 
following manner. Initially, spring 396 presses plunger 386 with 
sufficient force to assure that O-ring 388 is maintained in contact with 
seating surface 384 despite any negative pressure existent in suction 
chamber 304. However, should an excess negative pressure exist in 
collection chamber 304, the physician or operator of drainage apparatus 
300 acts to relieve this excess negative pressure by depressing push 
button 394. As soon as push button 394 is depressed, plunger 386 is moved 
downwardly so that O-ring 388 is no longer in contact with sealing surface 
384. This allows atmospheric air to pass around push button 394 and stem 
390 through aperture 392. The atmospheric air then exerts a pressure on 
umbrella valve 410. Umbrella valve 410 is chosen so as to require a 
predetermined difference in pressure on either side of umbrella valve 410 
before umbrella valve 410 will open. Thus, if the excess negative pressure 
on the collection chamber side of umbrella valve 410 is sufficient, the 
air at atmospheric pressure entering valve body 382 is sufficient to open 
umbrella valve 410 as well and pass through apertures 408 to relieve the 
excess negative pressure in collection chamber 304. 
It should also be appreciated that excess negative pressure relief means 
380 operates only to relieve the excess negative pressure in collection 
chamber 304 and not to destroy all negative pressure therein. Thus, where 
a negative pressure of -20 cmH.sub.2 O is desired in collection chamber 
304, umbrella valve 410 is chosen such that umbrella valve 410 closes when 
the difference in pressure between atmosphere in collection chamber 304 is 
-20 cmH.sub.2 O. Therefore, when relieving excess negativity in collection 
chamber 304 by the depression of push button 394, umbrellavalve 410 
automatically closes when sufficient air has been admitted into collection 
chamber 304 to relieve the excess negativity down to the -20 cmH.sub.2 O 
when suction is applied. If no suction is applied, excess negativity is 
reduced to -10 cmH.sub.2 O. 
Depicted in FIG. 9 is an alternative embodiment of a control means 430 
which can be used in place of control means 316 of drainage apparatus 300. 
In this embodiment, control means 430 includes a gross pressure adjusting 
means 431 including a gross biased valve means 432 and a fine pressure 
adjusting means 433 including a fine biased valve means 434. As shown, 
fine biased valve means 434 is substantially similar to biased valve means 
360 described above. Thus, fine biased valve means 434 includes a ball 436 
which is spring biased into position against a valve inlet 438. At the 
other end, fine biased valve means 434 includes a passageway inlet 440 
which is fluidly connected to passageway 310 and hence collection chamber 
304 of drainage apparatus 300. Located between valve outlet 438 and 
passageway inlet 440 is a valve outlet 442. Valve outlet 442 includes a 
bore 444 of limited size to restrict the flow of gases through bore 444. 
Bore 444 communicates with the interior of gross biased valve means 432. 
Gross biased valve means 432 includes a ball 446 which is biased against a 
valve inlet 448. At the other end, gross biased valve means 432 includes a 
valve outlet 450 which is directly connected to suction outlet 308 of 
drainage apparatus 300. It should be appreciated that both valve inlet 438 
and valve inlet 448 are fluidly connected to atmosphere through aperture 
358 in drainage apparatus 300. It should also be appreciated that valve 
outlet 450 has a relatively small diameter so that the flow of fluids 
through valve outlet 450 is also restricted. 
In operation, conrol means 430 functions in the following manner. When 
suction outlet 308 is connected to a suitable source of suction, ball 446 
is immediately raised off of valve inlet 448 by the appended suction. The 
spring biasing of ball 446 is sufficient to create a negative pressure in 
gross biased valve means 432 of slightly more than -20 cmH.sub.2 O. This 
negative pressure of slightly more than -20 cmH.sub.2 O is then applied 
through bore 444 to the interior of fine biased valve means 434. The 
spring biasing of ball 436 and the adjustment of valve inlet 438 is then 
designed to cause the pressure within fine biased valve means 434 to 
achieve a steady state negative pressure of approximately -20 cmH.sub.2 O. 
This negative pressure is then exerted through passageway inlet 440 to 
collection chamber 304. By the use of two biased valve means, a greater 
degree of accuracy in control of the negative pressure within the 
collection chamber is achieved. In addition, the restriction of bore 444 
and valve outlet 450 similarly assures that not too great a negative 
pressure is exerted on collection chamber 304 despite any changes in 
suction at suction outlet 308. 
In experiments performed with such a biased valve control means, it has 
been found that for an applied suction at suction outlet 308 from 20 mmHg 
to 200 mmHg, a negative pressure in the collection chamber of -20 
cmH.sub.2 O+1 cmH.sub.2 O can be achieved. 
Depicted in FIGS. 10 and 11 is an alternative embodiment of an air leak 
indicating means 460 which can be used in place of air leak indicating 
means 314 in drainage apparatus 300 or air leak indicating means 26 in 
drainage apparatus 10. Air leak indicating means 460 is used to indicate 
not only flow but also the quantitative value of this flow. Air leak 
indicating means 460 is similar to the flow indicating means disclosed in 
U.S. Pat. No. 3,782,497 (Bidwell et al) which is herein incorporated by 
reference. Air leak indicating means 460 includes an air leak chamber 462 
which is divided into an inlet side 464 and an outlet side 466 by a wall 
468. Bottom wall 470 of air leak chamber 462 is also slanted at about a 6 
degree angle as shown. Inlet side 464 is fluidly connected to short 
passage 330 while outlet side 466 is fluidly connected to short passage 
344 as shown. 
Inlet side 464 is separated from outlet side 466 by wall 468 and by a 
divider member 472 wich is spaced above bottom wall 470 and parallel 
thereto. As shown, member 472 includes a plurality of vertical apertures 
474 spaced along the length thereof. Located above member 472 and between 
adjacent aperture 474 is a plurality of vanes 476. Located between vanes 
476 and short passage 344 is a baffle 478 as shown. It should also be 
appreciated that a liquid 480 is provided in flow chamber 462. 
In operation, air leak indicating means 460 functions in the following 
manner. As gases are withdrawn through short passage 330 to short passage 
344 by the operation of drainage apparatus 300, these gases bubble through 
liquid 480. Initially, the gases pass through aperture 474 which is 
uppermost in member 472. However, as the flow of gases increases, the 
gases additionally flow through succeeding lower apertures 474 along the 
length of member 472. Thus, as explained in the above-identified patent, 
the number of apertures 474 through which gases bubble, or rather the 
lowermost of the apertures 474 through which the gases bubble, indicates 
the volume of flow through air leak indicating means 460. Suitable indicia 
(not shown) are be provided on the outside of drainage apparatus 300 to 
indicate this to the user. It should also be appreciated that baffle 478 
prevents any bubbles which are formed by the gases passing through liquid 
480 and apertures 474 from being drawn into short passage 344. 
Although the present invention has been described with respect to exemplary 
embodiments thereof, it will be understood by those of ordinary skill in 
the art that variations and modifications can be effected within the scope 
and spirit of the invention.