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Observations on Dynamics of Acute Urinary Retention in Man
TH"~ .Toun::.--rAL OF UROLOGY Vol. 67, No. 6, .June 1952 Printed 1:n U.S.A.~
OBSERVATIO)JS ON DYl'{AMICS OF ACUTE URINAH,Y RETENTION I)J MAN JOHN D.. LAWSON, ARTHUR L. SCHNEEBERG
AND
WILLIAM B TOMLINSON
/i'ruin the Harrison Department of Surgical Research, School of Medicine. University of Pennsylvcmfo and the Philadelphia General Hospital. Philadelphia
In a previous report (Lawson and Tomlinson) it was shmvn that when dogs are subjected to acute urinary retention the pressure in the dog's bladder increases to a peak as the bladder is distended, then decreases although bladder volume is constantly increasing. It was also found that if saline vrnre added to the distending bladder, the pressure changes subsequent to the addition of saline would depend upon the portion of the curve represented at that time. For example, if the pressure observed were on the ascending portion of the curve, the addition of saline would cause the bladder pressure to .increase sharply. If the plateau of pressure had been reached, the pressure observed following the addition of saline would remain essentially constant; likewise, if the pressure observed represented the descending portion of the curve the additional fluid would cause a sharp fall in bladder pressure. For obvious reasons the dog experiments could not be completely reduplicated on humans and hence the continuous production of a pressure-distention curve such as seen in the dog experiments could not be obtained. Hovvever, since all degrees of bladder distention are seen in medical patients, pressures could be observed which should correspond to all portions of the pressure-distention curves seen in the dogs, providing such curves obtain in human bladder distention. Since the dog experiments demonstrated that the portion of the curve involved at any given pressure could be determined by the addition of saline to the distending bladder, it was decided to apply this approach to human bladders in various stages of distention. The results of these studies are shmvn in figure L Graph A shows the effect of the addition of 80 cc of saline to a bladder on the ascending port.ion of the curve. Graph B shows the effect of adding 80 cc of saline to a bladder on the pressure plateau. Graphs C and D shmv the effect of adding saline to bladders representing the descending portion of the curveo From curves of the above types, one may demonstrate that the human bladder has distention characteristics similar to those seen in dogs. Although 80 cc of saline were added to the experiments recorded, 10-15 cc: of saline were found to demonstrate similar pressure changes. T'herefore, the portion of the pressure-distention curve involved at any moment during urinary retention can be demonstrated by the addition of small amounts of saline to the bladder. In actual clinical practice one can determine bladder pressure by attaching a, small length of sterile transparent flexible tubing to the inserted catheter hy means of a glass adapter and observing the height to which urine rises in the tubing above the level of the bladder. Furthermore, with practice, bladder pressures ean be fairly well estimated by palpation of the distending bladder, D51
952
LAWSON, SCHNEEBERG AND TOMLINSON
providing there is no muscle guarding or straining, and the abdominal wall is not too thick. Since it is common procedure in some urological clinics to treat acute urinary retention by the removal of 200 cc urine rapidly (to relieve pain) before slowly decompressing the bladder, we decided to observe a group of patients in acute urinary retention as to initial bladder pressure and the pressure change following the removal of 200 cc urine. It will be seen (fig. 2) that the higher the initial bladder pressures, the greater the fall of pressure when 200 cc of urine are withdrawn. The bladder pressure following the removal of 200 cc of urine actually falls, at times, to less than onefifth of the original pressure. Obviously, as far as urinary hydrodynamics are concerned, the withdrawal of the initial 200 cc of urine should be as damaging as
CC. ADDED BO FIG. 1
complete emptying of the bladder if the bladder pressure is above 30 cm. of water pressure. Hryntschak and Creevy have stated that sudden decompression of acute urinary retention of all degrees is without immediate danger. Much of this reasoning has been based on the fact that hugely distended bladders containing up to 14 liters of urine have been rapidly decompressed without deleterious effects. No statements were made concerning the bladder pressures involved. It would seem logical that such greatly distended bladders would be most likely on the descending portion of the pressure-distention curve and hence the pressure concerned might be quite low. In fact, we have seen bladders with pressures of only about 5 cm. of water although their contents measured four or five liters. Some of these bladders with such low pressures were seen in patients who had no previous history of urological disease but who had sustained head trauma. On the other hand, some of the bladders which contained less than 500 cc of urine had the highest pressures recorded (about 60 cm. water pressure).
DYNAMICS OF URINARY RETENTION
953
It has been inferred in the past by some investigators that any bladder can be rapidly decompressed without immediate danger This is based on the fact that hugely distended bladders have been rapidly decompressed without harmful sequellae. This is a "non sequitur" conclusion, because small bladders may have very high pressures, whereas huge bladders may have very luw pressures. Comprehension of these basic physical principles may help explain -why we find two opposed groups of urologists. one group proposing rapid decompression of all acute retention, and the other stating the observed occurrence of post-retention anuria and "bladder shock" following rapid decompression. During our study we observed no harmful results from sudden decompression of all degrees of bladder distention. However, reactions to sudden decompression definitely can occur and in retrospect in our clinics those reported were inpatients with smaller bladder volumes. Also, there has been no evidence of so called pm;t,
Fm. 2
evacuation splanchnic pooling -with its subsequent changes in pulse and blood pressures either in dogc1 or man. It is our opinion, on the basis of experimental data, that the attitude of treating a greatly dic1tended bladder more cautiously than a smaller one with regard to bladder shock and post-retention anuria is incorrect if not dangerous. However, on occac1ion, hugely distended bladders -will show submuc:osal and mucosa.I thromboses and hemorrhages. Subsequent care with regard to prevention of infection in such traumatized bladders is therefore mandatory. Another observation which may be of significance with regard to rapid versus slow bladder decompression was the fact that when canine bladders which had been subjected to great degrees of distention ,vere decompressed rapidly many thrombosed vessels -were found in the bladder -wall. Subsequent to thrombosis there wac1 fibrosis of the bladder. Indeed, repeated bladder dic1tentions werA utilized to produce fibrotic bladders for the determination of kidney pressures.
954
LAWSON, SCHNEEBERG AND TOMLINSON
Since the bladder vessels were greatly stretched and subjected to considerable trauma it was found that when the bladder was rapidly decompressed and the bladder subsequently contracted these vessels were kinked and there were secondary thromboses. The question of prime importance seemed to be whether bladder thromboses could be minimized by slow decompression. It would seem logical that with slower decompression the vessels might contract enough to reduce vascular kinking with its attendant thrombosis and secondary scarring. This question is being further investigated. Occasionally following decompression of acute urinary retention the patient is found to be anuric. This has been explained on a reflex basis. On the other hand, we believe that this anuria may well be secondary to renal parenchymal swelling with subsequent decrease or absence of urinary output. This swelling with its
Go----.... .,. "
.•
"
,.
.
•
"
•
D-..~~--~~-
a,n.oo£A 30 DD VOLUfflE CC. FIG. 3
subsequent increase in intranephric pressure becomes progressively more important in diseased kidneys where there is little renal reserve. e have been able to demonstrate kidney swelling in dogs subjected to acute urinary retention by the following: 1) When the kidney capsule is incised the parenchyma bulges through the capsular incision, whereas this does not occur in normal kidneys. 2) This bulging kidney parenchyma bleeds readily when the cortex is incised although urinary output was decreased. 3) There was microscopic evidence of cellular edema and architectural derangement in the kidney structure. It is our opinion at this time that no bladder with a pressure greater than 30 cm. of water be decompressed rapidly, and if slow decompression is used the initial 200 cc should not be quickly withdrawn but decompression should be conducted slowly "ab initio". There are several other facts which came to light during the course of our observations. It was found that there is absolutely no patient-to-patient correlation
,v
DYNAMICS OF URINARY RETENTION
955
het,rnen observed bladder volume and bladder pressure (fig. 3). The elastic characteristics of the bladders studied ,vere highly variable so that no overall correlation could be made bet,Yeen the portion of the pressure-distention curve involved and the bladder volume at any particular moment. This is most probably explained by the fact that the urological lesions were diverse. Hence, in a bladder ,vith dilatation secondary to prostatic hypertrophy the peak pree1sure w,1,s observed to occur murh later ,vith regard to bladder volume than in retention secondary to head trauma where no previous urinary tract disease existed However, if only bladders \Yhich were normal before retention occurred are considered, the co-efficient of correlati011 is about .67, showing fairly good volunrn-pres sure correlation in normal bladders during distention. SUJ\IivIARY AND CO-1\CLUSION
The distention characteristics of human urinary bladders are found to be similar to those of cuninc urinary bladders. The portion of the pressure-distention curve involved in any given cases of acute urinary retention can be determined by adding 10--lt) cc of saline and observing the resultant pressure changes, The higher the observed bladder pressure before 200 cc of urine ,ms remo\'ed, the greater will be the fall of pressure subsequent to its removal. Depending on the height of initial bladder pressure, the Yvithdra,rnl of 200 cc of urine can cause the bladder pressure to drop to less than one-fifth of its original value, The statement that greatly distended bladders should be decompressrod morn carefully than small bladders does not, hold true either theoretically or in actual practice, with the exception that in some greatly distended bladders submncosal thrnmboses and hemorrhage may make certain precautions necessary as regards the prevention of suhsequent bladder infection. The recording of bL:uldc"r pressure at the bedside can be earried out easily by attaching transparent sterile tubing to the inserted bladder catheter by means of a glass adapter, and observing the rise of urine in the tubing which is held above the level of the patient's bladder. -When in doubt about decompression of urinary retention in a patient, th8 pressure should be recorded and if above 30 cm. of \Yater pressure the bladder should be derompressed slo1Yly "ab initio." There is no patient-to-patient correlation between bladder volume and bladder pressure and no overall correlation behrnen observed bladder volume and the portion of the pressure-distention curve involved at this volume. Hmvever, if one only records the pressure-volume relationships in normal bladders during di~tention a co-efficient of correlation of approximately .67 will be found, showing fair pressure-volume correlation for normal bladders undergoing distentiou J\1any cases of post-retention anllria or oliguria may ,vell be explained on the basis of swelling of the kidney parenchyma ·with its subsequent increase in intranephric pressure. Hence the method of decompression may not be primarily responsible for the anuria, but rather the disruptive changes ,vithin the kidney due to urinary back pressure. 1n great degrees of bladder distention there is considerable vascular stretch
956
LAWSON, SCHNEEBERG AND TOMLINSON
and trauma, and when the bladder is rapidly decompressed we have observedkinking of the bladder vessels with its attendant thrombosis and secondary fibrosis. Slow decompression may minimize this kinking and reduce thrombosis and scarring. This problem will require further investigation. REFERENCES D.: Sudden decompression of chronically distended urinary bladder; clinical and pathologic study. Arch. Surg., 25: 356, 1932. HRYNTSCHAK, T.: Sudden and complete decompression versus slow emptying of the distended urinary bladder. J. Urol., 61: 545, 1949. LAWSON, J. D. AND TOMLINSON, W. B.: Observations on acute urinary retention in the dog. J. Urol., 66: 678-685, 1951 CREEVY, C.
r
OBSERVATIO)JS ON DYl'{AMICS OF ACUTE URINAH,Y RETENTION I)J MAN JOHN D.. LAWSON, ARTHUR L. SCHNEEBERG
AND
WILLIAM B TOMLINSON
/i'ruin the Harrison Department of Surgical Research, School of Medicine. University of Pennsylvcmfo and the Philadelphia General Hospital. Philadelphia
In a previous report (Lawson and Tomlinson) it was shmvn that when dogs are subjected to acute urinary retention the pressure in the dog's bladder increases to a peak as the bladder is distended, then decreases although bladder volume is constantly increasing. It was also found that if saline vrnre added to the distending bladder, the pressure changes subsequent to the addition of saline would depend upon the portion of the curve represented at that time. For example, if the pressure observed were on the ascending portion of the curve, the addition of saline would cause the bladder pressure to .increase sharply. If the plateau of pressure had been reached, the pressure observed following the addition of saline would remain essentially constant; likewise, if the pressure observed represented the descending portion of the curve the additional fluid would cause a sharp fall in bladder pressure. For obvious reasons the dog experiments could not be completely reduplicated on humans and hence the continuous production of a pressure-distention curve such as seen in the dog experiments could not be obtained. Hovvever, since all degrees of bladder distention are seen in medical patients, pressures could be observed which should correspond to all portions of the pressure-distention curves seen in the dogs, providing such curves obtain in human bladder distention. Since the dog experiments demonstrated that the portion of the curve involved at any given pressure could be determined by the addition of saline to the distending bladder, it was decided to apply this approach to human bladders in various stages of distention. The results of these studies are shmvn in figure L Graph A shows the effect of the addition of 80 cc of saline to a bladder on the ascending port.ion of the curve. Graph B shows the effect of adding 80 cc of saline to a bladder on the pressure plateau. Graphs C and D shmv the effect of adding saline to bladders representing the descending portion of the curveo From curves of the above types, one may demonstrate that the human bladder has distention characteristics similar to those seen in dogs. Although 80 cc of saline were added to the experiments recorded, 10-15 cc: of saline were found to demonstrate similar pressure changes. T'herefore, the portion of the pressure-distention curve involved at any moment during urinary retention can be demonstrated by the addition of small amounts of saline to the bladder. In actual clinical practice one can determine bladder pressure by attaching a, small length of sterile transparent flexible tubing to the inserted catheter hy means of a glass adapter and observing the height to which urine rises in the tubing above the level of the bladder. Furthermore, with practice, bladder pressures ean be fairly well estimated by palpation of the distending bladder, D51
952
LAWSON, SCHNEEBERG AND TOMLINSON
providing there is no muscle guarding or straining, and the abdominal wall is not too thick. Since it is common procedure in some urological clinics to treat acute urinary retention by the removal of 200 cc urine rapidly (to relieve pain) before slowly decompressing the bladder, we decided to observe a group of patients in acute urinary retention as to initial bladder pressure and the pressure change following the removal of 200 cc urine. It will be seen (fig. 2) that the higher the initial bladder pressures, the greater the fall of pressure when 200 cc of urine are withdrawn. The bladder pressure following the removal of 200 cc of urine actually falls, at times, to less than onefifth of the original pressure. Obviously, as far as urinary hydrodynamics are concerned, the withdrawal of the initial 200 cc of urine should be as damaging as
CC. ADDED BO FIG. 1
complete emptying of the bladder if the bladder pressure is above 30 cm. of water pressure. Hryntschak and Creevy have stated that sudden decompression of acute urinary retention of all degrees is without immediate danger. Much of this reasoning has been based on the fact that hugely distended bladders containing up to 14 liters of urine have been rapidly decompressed without deleterious effects. No statements were made concerning the bladder pressures involved. It would seem logical that such greatly distended bladders would be most likely on the descending portion of the pressure-distention curve and hence the pressure concerned might be quite low. In fact, we have seen bladders with pressures of only about 5 cm. of water although their contents measured four or five liters. Some of these bladders with such low pressures were seen in patients who had no previous history of urological disease but who had sustained head trauma. On the other hand, some of the bladders which contained less than 500 cc of urine had the highest pressures recorded (about 60 cm. water pressure).
DYNAMICS OF URINARY RETENTION
953
It has been inferred in the past by some investigators that any bladder can be rapidly decompressed without immediate danger This is based on the fact that hugely distended bladders have been rapidly decompressed without harmful sequellae. This is a "non sequitur" conclusion, because small bladders may have very high pressures, whereas huge bladders may have very luw pressures. Comprehension of these basic physical principles may help explain -why we find two opposed groups of urologists. one group proposing rapid decompression of all acute retention, and the other stating the observed occurrence of post-retention anuria and "bladder shock" following rapid decompression. During our study we observed no harmful results from sudden decompression of all degrees of bladder distention. However, reactions to sudden decompression definitely can occur and in retrospect in our clinics those reported were inpatients with smaller bladder volumes. Also, there has been no evidence of so called pm;t,
Fm. 2
evacuation splanchnic pooling -with its subsequent changes in pulse and blood pressures either in dogc1 or man. It is our opinion, on the basis of experimental data, that the attitude of treating a greatly dic1tended bladder more cautiously than a smaller one with regard to bladder shock and post-retention anuria is incorrect if not dangerous. However, on occac1ion, hugely distended bladders -will show submuc:osal and mucosa.I thromboses and hemorrhages. Subsequent care with regard to prevention of infection in such traumatized bladders is therefore mandatory. Another observation which may be of significance with regard to rapid versus slow bladder decompression was the fact that when canine bladders which had been subjected to great degrees of distention ,vere decompressed rapidly many thrombosed vessels -were found in the bladder -wall. Subsequent to thrombosis there wac1 fibrosis of the bladder. Indeed, repeated bladder dic1tentions werA utilized to produce fibrotic bladders for the determination of kidney pressures.
954
LAWSON, SCHNEEBERG AND TOMLINSON
Since the bladder vessels were greatly stretched and subjected to considerable trauma it was found that when the bladder was rapidly decompressed and the bladder subsequently contracted these vessels were kinked and there were secondary thromboses. The question of prime importance seemed to be whether bladder thromboses could be minimized by slow decompression. It would seem logical that with slower decompression the vessels might contract enough to reduce vascular kinking with its attendant thrombosis and secondary scarring. This question is being further investigated. Occasionally following decompression of acute urinary retention the patient is found to be anuric. This has been explained on a reflex basis. On the other hand, we believe that this anuria may well be secondary to renal parenchymal swelling with subsequent decrease or absence of urinary output. This swelling with its
Go----.... .,. "
.•
"
,.
.
•
"
•
D-..~~--~~-
a,n.oo£A 30 DD VOLUfflE CC. FIG. 3
subsequent increase in intranephric pressure becomes progressively more important in diseased kidneys where there is little renal reserve. e have been able to demonstrate kidney swelling in dogs subjected to acute urinary retention by the following: 1) When the kidney capsule is incised the parenchyma bulges through the capsular incision, whereas this does not occur in normal kidneys. 2) This bulging kidney parenchyma bleeds readily when the cortex is incised although urinary output was decreased. 3) There was microscopic evidence of cellular edema and architectural derangement in the kidney structure. It is our opinion at this time that no bladder with a pressure greater than 30 cm. of water be decompressed rapidly, and if slow decompression is used the initial 200 cc should not be quickly withdrawn but decompression should be conducted slowly "ab initio". There are several other facts which came to light during the course of our observations. It was found that there is absolutely no patient-to-patient correlation
,v
DYNAMICS OF URINARY RETENTION
955
het,rnen observed bladder volume and bladder pressure (fig. 3). The elastic characteristics of the bladders studied ,vere highly variable so that no overall correlation could be made bet,Yeen the portion of the pressure-distention curve involved and the bladder volume at any particular moment. This is most probably explained by the fact that the urological lesions were diverse. Hence, in a bladder ,vith dilatation secondary to prostatic hypertrophy the peak pree1sure w,1,s observed to occur murh later ,vith regard to bladder volume than in retention secondary to head trauma where no previous urinary tract disease existed However, if only bladders \Yhich were normal before retention occurred are considered, the co-efficient of correlati011 is about .67, showing fairly good volunrn-pres sure correlation in normal bladders during distention. SUJ\IivIARY AND CO-1\CLUSION
The distention characteristics of human urinary bladders are found to be similar to those of cuninc urinary bladders. The portion of the pressure-distention curve involved in any given cases of acute urinary retention can be determined by adding 10--lt) cc of saline and observing the resultant pressure changes, The higher the observed bladder pressure before 200 cc of urine ,ms remo\'ed, the greater will be the fall of pressure subsequent to its removal. Depending on the height of initial bladder pressure, the Yvithdra,rnl of 200 cc of urine can cause the bladder pressure to drop to less than one-fifth of its original value, The statement that greatly distended bladders should be decompressrod morn carefully than small bladders does not, hold true either theoretically or in actual practice, with the exception that in some greatly distended bladders submncosal thrnmboses and hemorrhage may make certain precautions necessary as regards the prevention of suhsequent bladder infection. The recording of bL:uldc"r pressure at the bedside can be earried out easily by attaching transparent sterile tubing to the inserted bladder catheter by means of a glass adapter, and observing the rise of urine in the tubing which is held above the level of the patient's bladder. -When in doubt about decompression of urinary retention in a patient, th8 pressure should be recorded and if above 30 cm. of \Yater pressure the bladder should be derompressed slo1Yly "ab initio." There is no patient-to-patient correlation between bladder volume and bladder pressure and no overall correlation behrnen observed bladder volume and the portion of the pressure-distention curve involved at this volume. Hmvever, if one only records the pressure-volume relationships in normal bladders during di~tention a co-efficient of correlation of approximately .67 will be found, showing fair pressure-volume correlation for normal bladders undergoing distentiou J\1any cases of post-retention anllria or oliguria may ,vell be explained on the basis of swelling of the kidney parenchyma ·with its subsequent increase in intranephric pressure. Hence the method of decompression may not be primarily responsible for the anuria, but rather the disruptive changes ,vithin the kidney due to urinary back pressure. 1n great degrees of bladder distention there is considerable vascular stretch
956
LAWSON, SCHNEEBERG AND TOMLINSON
and trauma, and when the bladder is rapidly decompressed we have observedkinking of the bladder vessels with its attendant thrombosis and secondary fibrosis. Slow decompression may minimize this kinking and reduce thrombosis and scarring. This problem will require further investigation. REFERENCES D.: Sudden decompression of chronically distended urinary bladder; clinical and pathologic study. Arch. Surg., 25: 356, 1932. HRYNTSCHAK, T.: Sudden and complete decompression versus slow emptying of the distended urinary bladder. J. Urol., 61: 545, 1949. LAWSON, J. D. AND TOMLINSON, W. B.: Observations on acute urinary retention in the dog. J. Urol., 66: 678-685, 1951 CREEVY, C.
r