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Studies in Normal Ureteral and Vesical Pressure1
STUDIES IN NORMAL URETERAL AND VESICAL PRESSURE 1 HENRY A. R. KREUTZMANN San Francisco, California
The most exact method of studying the actions of the various organs of the urinary tract is without doubt from observations upon the human body without the detrimental effect of any anesthetic. Trattner (1) stated that as most of the investigations upon ureteral contractions have been confined to observations upon excised ureteral segments, ureters removed in toto or upon ureters exposed by opening the abdominal cavity, they are not normal methods. For the purpose of obtaining data under conditions as nearly normal as possible, he devised an apparatus which records on a smoked drum the pressure changes in the ureter, the flow of urine in drops and the time in five-secon~ intervals. His experimental work was done on human beings, and the only abnormal conditions to which the ureter was subjected was the presence within its lumen of a catheter, and the resistance offered by this and by the outflow needle. With the exception of Trattner's work, the attempts to study urinary pressure in the human being have been almost entirely confined to measuring the bladder pressure. Rose (2) has devised an instrument which he calls a cystometer. With this he is able to register the changing intravesical pressure in millimeters of mercury synchronously with the cubic centimeters of fluid as they flow into the bladder. Campbell (3) studied the pressure changes produced by the gradual decompression of acutely distended bladders. 1 Read at the Annual Meeting of the Western Branch of the American Urological Association, Seattle, July 6, 1927.
517 THE JOURNAL OF UROLOGY, VOL. XIX, NO.
4:
518
HENRY A. R. K!REUTZMANN
Bumpus and Foulds (4) determined the intravesical tension in patients with hypertrophied prostates. We have studied the pressure both in the ureters and bladder of normal human beings under various conditions. Our apparatus and technique is much simpler, and as our determinations of the normal bladder pressure correspond with those of other investigators, we believe our methods to be just as accurate. Our procedure is as follows: A No. 26 cystoscope is inserted into the bladder. Through this No. 6 ureteral whistle tipped catheters are passed either into the ureters or the bladder, depending on the experiment. To the outer end of the catheters, pressure gauges, as devised at the Crowell Clinic (5) are attached. The pressure readings are in millimeters of mercury. The entire work was done on patients with no ·pathology of the urinary tract. NORMAL BLADDER PRESSURES
In studying the bladder pressure, we did not measure the amount of fluid injected and note the rise in pressure with the increasing dilatation as Rose has done. The maneuver was simply to fill the empty bladder and have the subject state when the first desire to void occurred. This pressure was recorded. The bladder was then distended to its utmost capacity and a second reading noted. The subject was then told to strain as much as possible to expel the solution. At the point of utmost compression a third reading was taken. In a number of instances we were not able to obtain the first reading because the cystoscope in itself caused an irritation of bladder and the subject was unable to recognize the first desire to void. The following protocol is typical of the findings in these cases: mm.
Desire to void. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Bladder completely full .. . ... .. . . . . . . .... . ... .... ... .. . . ..... . . . . .. 28 Bladder completely full and straining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
As will be noted, there is very little increase in intravesical pressure from the first desire to void, up to the point of maximum capacity.
STUDIES IN URETERAL AND VESICAL PRESSURE
519
There is, however, a great increase in pressure when the bladder is completely distended and the subject attempts to void. In no instance when the bladder was filled, did we observe any independent contractions of the bladder wall. This would have been registered immediately by an increase in the pressure readings of the manometer. URETERAL PRESSURE AT VARIOUS LEVELS
In this phase of the work, catheters were inserted to both kidney pelves and the pressures recorded simultaneously. The same maneuver was repeated at 20 and 10 cm. from the bladder. Two readings were taken at each level, the first with the patient . relaxed and the second when straining as if voiding. In order to determine the ureteral pressure, it was necessary to prevent the outflow of urine from the manometer by closing the pet cock at the outer end of the instrument. As a result, the urine secreted by the kidney collected in the ureter. This brought up the question whether we were measuring the normal urinary pressure in the ureter or merely the back pressure of an obstructed ureter. In an attempt to clear up this point, in several instances we kept the outer end of the manometer closed for fifteen to twenty minutes and watched the changes in pressure readings. This was done when the catheter was 10 cm. from the bladder. A rapid increase in pressure was noted, interspersed with normal peristaltic waves. After a time, the waves became more frequent and more violent. The needle of the manometer showed the waves to vary from 15 to 25 mm. Later on these oscillations became weaker and were irregular and indicated fatigue on the part of the ureter. In several instances at this point we permitted the ureter to drain for eight to ten minutes. The manometer was then closed again so that the urine could collect in the ureter. Observation showed that even after this rest period the peristaltic waves were quite weak. In no instance when the manometer was closed did the ureteral pressure equal the secretory pressure of the kidney nor did the
520
HENRY A. R. KREUTZMANN
subject once complain of pain in the kidney as one would expect in an acute hydronephrosis. As these experiments were not carried on longer than an hour, it is possible that sufficient time had not elapsed for the formation of hydronephrosis. In later experiments, in order to be certain that the pressures recorded were not due to back pressure, the manometer was never kept closed for a long period of time, but simply long enough for a column of urine to form and register on the dial. On comparing the two methods the only difference noted was rapid fatigue when the pet cock was kept closed for a long interval. Several times when the outflow of urine was obstructed and active peristalsis was noted, the needle of the manometer was seen to drop to zero. Trattner had also observed this phenomenon, but was unable to explain the cause. We believe it to be due to the fact that the urine had found its way around the catheter into the bladder. The following protocol is typical of the findings in ureteral pressure : RIGHT K IDNEY
L E FT KIDNEY
Catheter in kidney pelvis : Relaxed . . . .. .. ... . .... .. . . . ... .. ... . . .... . .. . . ... . . Straining . . . . .. .. . ..... . .. ..... . ..... ..... .. . . .. . . . .
8
8
32
32
Catheter 20 cm. in ureter : Relaxed . . . .. . . .. . . ... . . . . . .. ........ .... .. . . . . .. . . . Straining . ... ...... ... . . .. . .. . . . . . .... . ...... . . . ... .
14 46
54
16
18
66
66
Catheter 10 cm. in uret er : Relaxed . .... . . .. . ....... .. ... .. . .. . ..... . . . . .... . . . Straining . .... ... . .... .. .. . .. . ..... . ...... . . .. . . . . . .
10
The results of these tests show that the pressure is not equal on both sides at the same level. The only reason that this can be accounted for is the effect of the intra-abdominal organs upon the ureters. One also observes that the lower down the ureter the readings are taken, the greater is the pressure obtained. We also noted
STUDIES IN URETERAL AND VESICAL PRESSURE
521
that the peristaltic waves at the 10 cm. level were of greater force than at the other 20 cm. level. This is in accord with Lucas (6) who observed the peristaltic waves in the ureters of dogs. Karaffa-Korbutts (7) states that the ureteral pressure near the bladder is three times as great as the secretory pressure in the kidney pelvis. We have not found this to be so. Our observations show, however, that the intrapelvic pressure, both relaxed and straining, is less than that at the lower end of the bladder. SIMULTANEOUS URETERAL AND BLADDER PRESSURE
One catheter was inserted into the bladder and the other into one or the other ureter for a distance of 10 cm. Three readings were taken: first, on the first desire of the person to void; second, when the bladder was completely distended; and third, when the bladder was completely filled and an attempt was made to void. The purpose of these three tests was to simulate as nearly as possible the ureteral and vesical pressures produced by a person while voiding with the bladder comfortably distended and with the bladder overdistended. As the bladder was filled to the maximum, the peristaltic waves in the ureter increased in rate and amplitude. The force of the waves varied from 16 to 20 mm. Pflaumer (8) observing the ureteral orifices in female dogs through a cystoscope also noted an increase in the rate of contractions when the bladder is filled. He believes this to be due to a reflex irritation produced on nerves in or on the bladder wall. We also found that on increasing the amount of solution in the bladder, there occurred a distinct corresponding increase in the ureteral pressure. We made sure that it was not due to a tightening of the abdmninal muscles of the subjects by encouraging them to relax and by direct palpation of the abdomen. Sampson (9), experimenting on dogs, noted when the bladder was filled and the urethra was clamped, that there was an increase in the ureteral contractions, the ureter did not empty itself and occasionally there was a duplication of the ureteral contraction.
522
HENRY A. R. KREUTZMANN
We believe with Pflaumer that on distending the bladder, a reflex is set up which not only increases the peristalsis of the ureter, but also tends to splint the muscles of the ureters, put them on guard against possible reflux, thereby causing an increase in the intraureteral pressure as indicated on the manometer. The following data is characteristic of the results obtained in simultaneous observation of uretero-vesical pressure: BLADDER
Bladder partially full : Relaxed . ..... ............. . ... . . . . .. .... ... .... . . . . Straining . .. . ... . .. . .. ...... ..... . . ... .. ........ . .. . First desire to void : Relaxed . . . .... .. ... . .. . . ... . . . . .. . : .. . ... . ... .. . . . . Straining .... .. . .... . .... . . ... .. .... . . .. . ........ . . . Bladder distended: Relaxed . . . ..... .. . . ... . . .... . ... .... . ....... . . . . . . . Straining . . . . . ... ... . .. . . .. . . . .. ...... .. . .. .. .. .. . . .
4
28 10
48 62 96
LEFT URETER
10CM.
4 4-0
14 58
24
68
In the majority of cases, the ureteral pressure was less than the bladder pressure at each of the three readings. In some of the experiments the ureteral pressure was equal to or greater than the first two readings. However, the ureteral pressure was never found to be higher than that of the bladder filled to the maximum with the subject straining. There has been a great deal of discussion as to the possibility of reflux occurring in the presence of a normal urinary tract. A number of authors believe that with the bladder filled and the patient straining, it is possible for reflux to occur at the moment when the ureteral orifice opens to permit a spurt of urine to enter the bladder. When watching the ureteral orifice during a cystoscopy, it is quite evident that there is considerable power in the peristaltic wave from the way that the spurt of urine is shot away from the ureteral orifice.
523
STUDIES IN URETERAL AND VESICAL PRESSURE
Further evidence against reflux is furnished by the following protocol. CATHETER IN DISTENDED BLADDER
Relaxed ........ . .. . .. . .. .. .. . . .. . . . .. . .. . . . . ..... ... . Straining ... . .. .. . . . . ... . .. ... . . . . . ... . .. . ...... .. .. . .
* Peristaltic
CATHETER IN LEFT URETER
10 CM.
14
14
36
34*
wave occurred which increased the pressure to 52 mm.
We have noted in several instances, such as the one just noted, that the abdominal pressure plus that of the peristaltic wave was greater than the maximum bladder pressure. PRESSURE CHANGES IN A URETERAL STUMP
That intra-abdominal pressure plays a great part in increasing the ureteral pressure is evidenced from the following experiment. A patient was examined in whom two years previously the right kidney had been removed, but the ureter had been left in situ and a stump 19 cm. long was still present. A catheter was inserted into this closed ureter for a distance of 10 cm. No peristaltic waves were noted, and there was absolutely no pressure recorded on the manometer. Approximately 4 · cc. of sterile water were injected through the catheter. A pressure of 8 mm. was observed when the patient relaxed. This rose to 68 mm. on straining. Ten more cubic centimeters of water were now injected. As a result of the additional fluid, the pressure rose to 12 mm. on relaxation and 116 mm. on straining. In other words, the more solution that was injected into the. sac, the greater was the pressure produced. This experiment shows how important it is when measuring ureteral pressure, not to keep the ureter blocked for a long time. The continual excretion of urine into the kidney pelvis, combined with obstruction of the outlet with a catheter will result in various erroneous readings, such as have been produced in the ureteral stump, by injecting different amounts of fluid.
524
HENRY A. R. KREUTZMANN
Therefore, it is essential when taking the ureteral pressure to have the manometer closed for as short a time as possible. One will then obtain the true ureteral pressure and not that produced by a stasis of fluid in the ureter. A summary of the data obtained in this study on ureteral and vesical pressure is as follows: 1. There is very little focrease in the bladder pressure from the point of first feeling the desire to void to the point of maximum distention. 2. There is marked increase in the pressure when the act of micturition is attempted with the bladder completely filled. 3. In the normal distended bladder, no independent contractions of the bladder walls were noted. 4. Intra-ureteral pressure is not equal on both sides at the same moment. 5. The pressure in the ureters increases in direct proportion as one approaches the bladder. 6. As the bladder pressure increases by distention, there is a distinct proportional increase in the ureteral pressure. 7. Intra-abdominal pressure is an important factor in raising b0th the ureteral and vesical pressure. REFERENCES (1) TRATTNER: Jour. Urol., ii, May, 1924, 477----487. (2) RosE: Jour. Amer. Med. Assoc., lxxxviii, January 15, 1927, 151-156. (3) CAMPBELL: Jour. Urol., xvii, no. 3, March, 1927, 371-380.
(4) BUMPUS AND FOULDS: Jour. Amer. Med. Assoc., lxxxi, September 8, 1923, 821- 823. (5) (6) (7) · (8) (9)
ToDD AND THOMPSON: Jour. Urol., viii, 247- 256, 1922. LucAs: Jour. Physiol., xvii, 392-407, 1906. KARAFFA-KORBUTT: Folia Urologica, 1908. PFLAUMER: Zeitschr. f. Urol., xiii, 366-448, 1919. SAMPSON: Johns Hopkins Hosp. Bul., xiv, 334-352, 1903.
The most exact method of studying the actions of the various organs of the urinary tract is without doubt from observations upon the human body without the detrimental effect of any anesthetic. Trattner (1) stated that as most of the investigations upon ureteral contractions have been confined to observations upon excised ureteral segments, ureters removed in toto or upon ureters exposed by opening the abdominal cavity, they are not normal methods. For the purpose of obtaining data under conditions as nearly normal as possible, he devised an apparatus which records on a smoked drum the pressure changes in the ureter, the flow of urine in drops and the time in five-secon~ intervals. His experimental work was done on human beings, and the only abnormal conditions to which the ureter was subjected was the presence within its lumen of a catheter, and the resistance offered by this and by the outflow needle. With the exception of Trattner's work, the attempts to study urinary pressure in the human being have been almost entirely confined to measuring the bladder pressure. Rose (2) has devised an instrument which he calls a cystometer. With this he is able to register the changing intravesical pressure in millimeters of mercury synchronously with the cubic centimeters of fluid as they flow into the bladder. Campbell (3) studied the pressure changes produced by the gradual decompression of acutely distended bladders. 1 Read at the Annual Meeting of the Western Branch of the American Urological Association, Seattle, July 6, 1927.
517 THE JOURNAL OF UROLOGY, VOL. XIX, NO.
4:
518
HENRY A. R. K!REUTZMANN
Bumpus and Foulds (4) determined the intravesical tension in patients with hypertrophied prostates. We have studied the pressure both in the ureters and bladder of normal human beings under various conditions. Our apparatus and technique is much simpler, and as our determinations of the normal bladder pressure correspond with those of other investigators, we believe our methods to be just as accurate. Our procedure is as follows: A No. 26 cystoscope is inserted into the bladder. Through this No. 6 ureteral whistle tipped catheters are passed either into the ureters or the bladder, depending on the experiment. To the outer end of the catheters, pressure gauges, as devised at the Crowell Clinic (5) are attached. The pressure readings are in millimeters of mercury. The entire work was done on patients with no ·pathology of the urinary tract. NORMAL BLADDER PRESSURES
In studying the bladder pressure, we did not measure the amount of fluid injected and note the rise in pressure with the increasing dilatation as Rose has done. The maneuver was simply to fill the empty bladder and have the subject state when the first desire to void occurred. This pressure was recorded. The bladder was then distended to its utmost capacity and a second reading noted. The subject was then told to strain as much as possible to expel the solution. At the point of utmost compression a third reading was taken. In a number of instances we were not able to obtain the first reading because the cystoscope in itself caused an irritation of bladder and the subject was unable to recognize the first desire to void. The following protocol is typical of the findings in these cases: mm.
Desire to void. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Bladder completely full .. . ... .. . . . . . . .... . ... .... ... .. . . ..... . . . . .. 28 Bladder completely full and straining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
As will be noted, there is very little increase in intravesical pressure from the first desire to void, up to the point of maximum capacity.
STUDIES IN URETERAL AND VESICAL PRESSURE
519
There is, however, a great increase in pressure when the bladder is completely distended and the subject attempts to void. In no instance when the bladder was filled, did we observe any independent contractions of the bladder wall. This would have been registered immediately by an increase in the pressure readings of the manometer. URETERAL PRESSURE AT VARIOUS LEVELS
In this phase of the work, catheters were inserted to both kidney pelves and the pressures recorded simultaneously. The same maneuver was repeated at 20 and 10 cm. from the bladder. Two readings were taken at each level, the first with the patient . relaxed and the second when straining as if voiding. In order to determine the ureteral pressure, it was necessary to prevent the outflow of urine from the manometer by closing the pet cock at the outer end of the instrument. As a result, the urine secreted by the kidney collected in the ureter. This brought up the question whether we were measuring the normal urinary pressure in the ureter or merely the back pressure of an obstructed ureter. In an attempt to clear up this point, in several instances we kept the outer end of the manometer closed for fifteen to twenty minutes and watched the changes in pressure readings. This was done when the catheter was 10 cm. from the bladder. A rapid increase in pressure was noted, interspersed with normal peristaltic waves. After a time, the waves became more frequent and more violent. The needle of the manometer showed the waves to vary from 15 to 25 mm. Later on these oscillations became weaker and were irregular and indicated fatigue on the part of the ureter. In several instances at this point we permitted the ureter to drain for eight to ten minutes. The manometer was then closed again so that the urine could collect in the ureter. Observation showed that even after this rest period the peristaltic waves were quite weak. In no instance when the manometer was closed did the ureteral pressure equal the secretory pressure of the kidney nor did the
520
HENRY A. R. KREUTZMANN
subject once complain of pain in the kidney as one would expect in an acute hydronephrosis. As these experiments were not carried on longer than an hour, it is possible that sufficient time had not elapsed for the formation of hydronephrosis. In later experiments, in order to be certain that the pressures recorded were not due to back pressure, the manometer was never kept closed for a long period of time, but simply long enough for a column of urine to form and register on the dial. On comparing the two methods the only difference noted was rapid fatigue when the pet cock was kept closed for a long interval. Several times when the outflow of urine was obstructed and active peristalsis was noted, the needle of the manometer was seen to drop to zero. Trattner had also observed this phenomenon, but was unable to explain the cause. We believe it to be due to the fact that the urine had found its way around the catheter into the bladder. The following protocol is typical of the findings in ureteral pressure : RIGHT K IDNEY
L E FT KIDNEY
Catheter in kidney pelvis : Relaxed . . . .. .. ... . .... .. . . . ... .. ... . . .... . .. . . ... . . Straining . . . . .. .. . ..... . .. ..... . ..... ..... .. . . .. . . . .
8
8
32
32
Catheter 20 cm. in ureter : Relaxed . . . .. . . .. . . ... . . . . . .. ........ .... .. . . . . .. . . . Straining . ... ...... ... . . .. . .. . . . . . .... . ...... . . . ... .
14 46
54
16
18
66
66
Catheter 10 cm. in uret er : Relaxed . .... . . .. . ....... .. ... .. . .. . ..... . . . . .... . . . Straining . .... ... . .... .. .. . .. . ..... . ...... . . .. . . . . . .
10
The results of these tests show that the pressure is not equal on both sides at the same level. The only reason that this can be accounted for is the effect of the intra-abdominal organs upon the ureters. One also observes that the lower down the ureter the readings are taken, the greater is the pressure obtained. We also noted
STUDIES IN URETERAL AND VESICAL PRESSURE
521
that the peristaltic waves at the 10 cm. level were of greater force than at the other 20 cm. level. This is in accord with Lucas (6) who observed the peristaltic waves in the ureters of dogs. Karaffa-Korbutts (7) states that the ureteral pressure near the bladder is three times as great as the secretory pressure in the kidney pelvis. We have not found this to be so. Our observations show, however, that the intrapelvic pressure, both relaxed and straining, is less than that at the lower end of the bladder. SIMULTANEOUS URETERAL AND BLADDER PRESSURE
One catheter was inserted into the bladder and the other into one or the other ureter for a distance of 10 cm. Three readings were taken: first, on the first desire of the person to void; second, when the bladder was completely distended; and third, when the bladder was completely filled and an attempt was made to void. The purpose of these three tests was to simulate as nearly as possible the ureteral and vesical pressures produced by a person while voiding with the bladder comfortably distended and with the bladder overdistended. As the bladder was filled to the maximum, the peristaltic waves in the ureter increased in rate and amplitude. The force of the waves varied from 16 to 20 mm. Pflaumer (8) observing the ureteral orifices in female dogs through a cystoscope also noted an increase in the rate of contractions when the bladder is filled. He believes this to be due to a reflex irritation produced on nerves in or on the bladder wall. We also found that on increasing the amount of solution in the bladder, there occurred a distinct corresponding increase in the ureteral pressure. We made sure that it was not due to a tightening of the abdmninal muscles of the subjects by encouraging them to relax and by direct palpation of the abdomen. Sampson (9), experimenting on dogs, noted when the bladder was filled and the urethra was clamped, that there was an increase in the ureteral contractions, the ureter did not empty itself and occasionally there was a duplication of the ureteral contraction.
522
HENRY A. R. KREUTZMANN
We believe with Pflaumer that on distending the bladder, a reflex is set up which not only increases the peristalsis of the ureter, but also tends to splint the muscles of the ureters, put them on guard against possible reflux, thereby causing an increase in the intraureteral pressure as indicated on the manometer. The following data is characteristic of the results obtained in simultaneous observation of uretero-vesical pressure: BLADDER
Bladder partially full : Relaxed . ..... ............. . ... . . . . .. .... ... .... . . . . Straining . .. . ... . .. . .. ...... ..... . . ... .. ........ . .. . First desire to void : Relaxed . . . .... .. ... . .. . . ... . . . . .. . : .. . ... . ... .. . . . . Straining .... .. . .... . .... . . ... .. .... . . .. . ........ . . . Bladder distended: Relaxed . . . ..... .. . . ... . . .... . ... .... . ....... . . . . . . . Straining . . . . . ... ... . .. . . .. . . . .. ...... .. . .. .. .. .. . . .
4
28 10
48 62 96
LEFT URETER
10CM.
4 4-0
14 58
24
68
In the majority of cases, the ureteral pressure was less than the bladder pressure at each of the three readings. In some of the experiments the ureteral pressure was equal to or greater than the first two readings. However, the ureteral pressure was never found to be higher than that of the bladder filled to the maximum with the subject straining. There has been a great deal of discussion as to the possibility of reflux occurring in the presence of a normal urinary tract. A number of authors believe that with the bladder filled and the patient straining, it is possible for reflux to occur at the moment when the ureteral orifice opens to permit a spurt of urine to enter the bladder. When watching the ureteral orifice during a cystoscopy, it is quite evident that there is considerable power in the peristaltic wave from the way that the spurt of urine is shot away from the ureteral orifice.
523
STUDIES IN URETERAL AND VESICAL PRESSURE
Further evidence against reflux is furnished by the following protocol. CATHETER IN DISTENDED BLADDER
Relaxed ........ . .. . .. . .. .. .. . . .. . . . .. . .. . . . . ..... ... . Straining ... . .. .. . . . . ... . .. ... . . . . . ... . .. . ...... .. .. . .
* Peristaltic
CATHETER IN LEFT URETER
10 CM.
14
14
36
34*
wave occurred which increased the pressure to 52 mm.
We have noted in several instances, such as the one just noted, that the abdominal pressure plus that of the peristaltic wave was greater than the maximum bladder pressure. PRESSURE CHANGES IN A URETERAL STUMP
That intra-abdominal pressure plays a great part in increasing the ureteral pressure is evidenced from the following experiment. A patient was examined in whom two years previously the right kidney had been removed, but the ureter had been left in situ and a stump 19 cm. long was still present. A catheter was inserted into this closed ureter for a distance of 10 cm. No peristaltic waves were noted, and there was absolutely no pressure recorded on the manometer. Approximately 4 · cc. of sterile water were injected through the catheter. A pressure of 8 mm. was observed when the patient relaxed. This rose to 68 mm. on straining. Ten more cubic centimeters of water were now injected. As a result of the additional fluid, the pressure rose to 12 mm. on relaxation and 116 mm. on straining. In other words, the more solution that was injected into the. sac, the greater was the pressure produced. This experiment shows how important it is when measuring ureteral pressure, not to keep the ureter blocked for a long time. The continual excretion of urine into the kidney pelvis, combined with obstruction of the outlet with a catheter will result in various erroneous readings, such as have been produced in the ureteral stump, by injecting different amounts of fluid.
524
HENRY A. R. KREUTZMANN
Therefore, it is essential when taking the ureteral pressure to have the manometer closed for as short a time as possible. One will then obtain the true ureteral pressure and not that produced by a stasis of fluid in the ureter. A summary of the data obtained in this study on ureteral and vesical pressure is as follows: 1. There is very little focrease in the bladder pressure from the point of first feeling the desire to void to the point of maximum distention. 2. There is marked increase in the pressure when the act of micturition is attempted with the bladder completely filled. 3. In the normal distended bladder, no independent contractions of the bladder walls were noted. 4. Intra-ureteral pressure is not equal on both sides at the same moment. 5. The pressure in the ureters increases in direct proportion as one approaches the bladder. 6. As the bladder pressure increases by distention, there is a distinct proportional increase in the ureteral pressure. 7. Intra-abdominal pressure is an important factor in raising b0th the ureteral and vesical pressure. REFERENCES (1) TRATTNER: Jour. Urol., ii, May, 1924, 477----487. (2) RosE: Jour. Amer. Med. Assoc., lxxxviii, January 15, 1927, 151-156. (3) CAMPBELL: Jour. Urol., xvii, no. 3, March, 1927, 371-380.
(4) BUMPUS AND FOULDS: Jour. Amer. Med. Assoc., lxxxi, September 8, 1923, 821- 823. (5) (6) (7) · (8) (9)
ToDD AND THOMPSON: Jour. Urol., viii, 247- 256, 1922. LucAs: Jour. Physiol., xvii, 392-407, 1906. KARAFFA-KORBUTT: Folia Urologica, 1908. PFLAUMER: Zeitschr. f. Urol., xiii, 366-448, 1919. SAMPSON: Johns Hopkins Hosp. Bul., xiv, 334-352, 1903.