Postoperative bladder distention: Measurement with bladder ultrasonography

Postoperative Bladder Distention: Measurement With Bladder Ultrasonography A M Y J. W A R N E R , BSN, RN S U S A N PHILLIPS, RN K A R I N RISKE, RN M A R I - K A Y H A U B E R T , BSN, RN, CCRN N A N C Y L A S H , BSN, RN Bladder distention is a common postoperative occurrence. A process improvement project was conducted at a Midwestern Veteran Affairs Medical Center to determine whether a n e w method for detecting bladder distention, bladder ultrasonography, was more effective than manual palpation in the perianesthesia setting. Data were collected on 494 men over a 9-month period using bladder ultrasonography. Of those patients, 19.4 % had postoperative bladder distention with greater than 400 mL of urine. This compared with 1.4 % of patients who had bladder distention detected during the previous year using manual palpation. Data from the project supported the use of bladder ultrasonography as being more effective than manual palpation in the assessment of postoperative bladder distention in the PACU. 9 2000 by American Society of PeriAnesthesia Nurses.

LADDER DISTENTION is a common postoperative occurrence, with resultant urinary retention occurring in 7% to 25% of patients. 1 The urge to void is usually felt at approximately 250 mL of urine. 2 Although the normal bladder capacity is 450 to 500 mL, 3 bladder distention begins to occur at 400 mL of urine. There are several reasons why bladder distention occurs, including the loss of bladder tonO and decreased sensation of fullness 3 when the bladder volume exceeds 500 mL. Anesthe-

B

Amy J. Warner, BSN, RN, is a PACU/OR Staff Nurse, Susan Phillips, RN, is a PACU Staff Nurse and TICU/SICU Critical Care Nurse, Karin Riske, RN, is a PACU Staff Nurse, Mari-Kay Haubert, BSN, RN, CCRN, is a PACU Staff Nurse, and Nancy Lash, BSN, RN, is a PACU Staff Nurse at the Veteran Affairs Medical Center, Ann Arbor, MI. Address correspondence to Amy J. Warner, BSN, RN, 8476 Berkshire Dr, Ypsilanti, M148198. 9 2000 by American Society of PeriAnesthesia Nurses. 1089-9472/00/1501-0005503.00/0

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sia, medications, and reflex spasms of the bladder sphincters from excessive pain or anxiety also may lead to distention. Many of these factors may contribute to the patient experiencing difficulty in voiding. Clinical signs and symptoms associated with bladder distention include a palpable bladder, elevated blood pressure in the absence of pain and without a history of hypertension, a history of renal problems, and patient complaints of a sensation to void with the inability to do so. Other factors affecting bladder distention are large amounts of intravenous fluid received during surgery and a prolonged length of surgery. The clinical parameters as noted above provide the PACU nurse with some guidelines to follow. However, none of these factors is completely accurate. Although intermittent straight catheterization of a patient is a more accurate technique for assessing urinary retention, it is invasive and places the patient at risk for a urinary tract infection. It is Journal of PeriAnesthesia Nursing, Vol 15, No 1 (February), 2000: pp 20-25

POSTOPERATIVE BLADDER DISTENTION also uncomfortable for the patients and is time consuming for the patients and staff. Obesity and abdominal dressings are 2 factors that may make palpation of the bladder difficult. In addition, palpation is often painful for patients with abdominal incisions. Palpation also may be difficult with elderly patients because of the redistribution of fat from the extremities to the trunk area, which occurs with advanced age. 3 Patients may express the need to void when the bladder is empty, depending on whether the bladder was manipulated during surgery or whether a urinary catheter was inserted during surgery. Both bladder manipulation and indwelling urinary catheters contribute to bladder spasms, giving the patient the sensation of a full bladder. Alternatively, bladder ultrasonography provides a safe, comfortable, and timesaving method for the detection of urinary retention. Specifically, bladder volume measurements by ultrasound provide an accurate assessment of the degree of bladder enlargement, thereby facilitating appropriate intervention to prevent bladder distention and unnecessary catheterization. 2 The cost of a bladder scanner is between $6,000 and $10,000. The bladderscan method used with the bladder management program is cost-effective in terms of patient comfort, decreased risk of trauma and iatrogenic infection, equipment cost, and nursing time, with a reduction in the number of unnecessary catheterizations. 2 The calculated savings were $1,100 to $1,500 per month. 2 THE NEED FOR PROCESS IMPROVEMENT

Using a previously established bladder protocol (Table 1) at the Veteran Affairs Medical Center (VAMC), 1.4% of surgical patients recovering in

Table 1. Previous Bladder Protocol for PACU (July 1995) Consider bladder palpation for the following factors: 9 Minimal Estimated Blood Loss (EBL) <200 mL 9 Amount of IV fluids received: >1,000 mL (patients NPO with an IV before surgery) >2,000 mL (patients NPO without an IV before surgery) 9 Drains: none or output <50 mL 9 If not voided within 6 hours 9 If in the operating room more than 4 hours 9 If no complaints of pain and has an elevated blood pressure without a history of hypertension If bladder is palpable, discuss intermittent straight catheterization need with anesthesia staff.

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Table 2. Revised Bladder Protocol for PACU (October 1998) Scan the bladders of all patients except: 9 Patients with Foley catheters (currently or during surgery) 9 Patients with renal failure who do not normally void 9 Patients for electroconvulsive therapy (ECT), cardioversion, or radiology procedures Scan bladders within 1 hour of arrival to PACU, then every 2 hours until bladder is emptied, then every 4 hours. For amounts scanned >400 mL and patient is unable to void: 9 Discuss intermittent straight catheterization (ISC) need with anesthesia staff 9 If patient is an outpatient and amount scanned in is less than 500 mL, continue to monitor and inform ambulatory surgery nurse of results If patient voids for a smaller amount than the amount scanned, subtract the amount voided from the amount scanned. If the difference is greater than 400 mL, discuss ISC need with anesthesia staff.

the PACU in 1997 were noted to have bladder distention. All patients suspected of having bladder distention were catheterized. However, patients were occasionally noted to have full bladders with associated bladder distention after discharge from the PACU. Because this protocol was not effective in identifying all patients with potential bladder distention, the need for an improved method became apparent. The Bladderscan BVI 2500 (Diagnostic Ultrasound Corporation, Redmond, WA) was purchased with the goal of increasing detection of bladder distention before discharge from the PACU. DESIGNING THE PROJECT IMPROVEMENT PLAN

A new protocol using the bladderscan equipment was developed (Table 2). This project, using the revised protocol, includes data from 494 men who were either outpatients or admit day of surgery patients over a 9-month period between January 1998 and September 1998. All patients received some type of anesthesia (general, spinal, regional block, or MAPS [monitored anesthesia with pharmacological support]). Patients were not allowed to eat or drink after midnight and did not receive intravenous fluids before surgery (Table 3). Patients were instructed to void before their operation. Those who had a urinary catheter or voided intraoperatively, before ultrasonography, were excluded from the project data set. Patients' ages ranged from 19 to 96 years, with

WARNER ET AL

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Table 3. Criteria for Process Improvement Project

Table 4. Correlation Between Bladder Volumes and Contributing Factors

9 Male Standard

9 Outpatients or admit day of surgery patients (n = 494)

Excluding: 9 Patients with urinary catheters 9 Patients who voided intraoperatively

Bladder volume

9 Patients with renal failure and do not void

Age

Range

Mean

0-1,000

274.28

170,92

58.80

13.86

100-2,600 1,033.24

443.73

19-96

Pearson

Deviation Correlation

R2

0.072

.005

0.051

.003

0.149

.022

Fluid received

the mean age of 58.80 (Fig 1). The study included a range of ages to optimize the generalizability of the results to the practices of the VAMC PACU nurse.

intraoperatively Length of surgery

30"-6 ~

2.11

1.03

DATA COLLECTION

PACU nurses trained to use the ultrasonography equipment scanned all patients' bladders within 1 hour of arrival in the PACU. The procedure consists of placing the oriented probe on the patient's abdomen and pushing the button. The scanner provides a picture of the volume scanned. When the picture is completely within the circle on the scanner, an accurate reading has occurred. The numerical data are given to the left of the picture and documented on the PACU record. Other data collected included length of surgery, amount of intravenous fluid received during surgery, type of anesthesia received, age, and surgical service. Data were retrieved from the PACU, intraoperative, and anesthesia records. Bladder volumes greater than 400 mL required further action. These actions included strongly encouraging the patient to void and continuing to monitor bladder volume or performing an intermittent straight catheterization.

PROCESS IMPROVEMENT RESULTS (Table 4)

The duration of the operations ranged from 30 minutes to 6 hours. Sixty-nine (72%) of the surgeries were less than 3 hours long (Fig 2). The mean length was 2.11, with a standard deviation of 1.03. The correlation between the length of surgery and the bladder volume was low (Pearson correlation coefficient = 0.149, R 2 = .022). The amount of intravenous fluid received during surgery varied from 200 to 2,600 mL (Fig 3). The mean amount received was 1,033.24 mL, with a standard deviation of 443.73 mL. Thirty-three (34%) patients received greater than 1,300 mL intravenous fluid. The correlation between the amount of fluid received intraoperatively and bladder volume was very low (Pearson correlation coefficient = 0.051, R 2 = .003). Patient ages ranged from 19 to 96 years (Fig 4). The mean age in this study was 58.80, with a

90

80

III

70

II

II

~=5o

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4o

II

30

I!

II

20

~o _ i l 19-25

26-30 31-35

36-40

41-45 46-50

51-55

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Age group

76-80

81-85 86-90 91-95 96-100

Fig 1. Age of male patients.

POSTOPERATIVE BLADDER DISTENTION

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120

[]

100

80

28o "6 40

20

0.5 hours

1 hour

1.5 hours 2 hours

2.5 hours

3hours

3.5 hours

4 hours

4.Shours 5 hours

5.5 hours

6 hours

Time

Fig 2.

Length of surgery versus bladder volume.

JITota113< 400mL B> 400mL]

standard deviation of 13.86. The correlation between the age of the patient and the bladder volume was low (Pearson correlation coefficient = 0.072, R 2 = . 0 0 5 ) . The ages of the patients with a bladder volume greater than 400 mL ranged from 25 to 82 years. Thirty-four percent of the surgeries were done by otolaryngology. Twenty-five percent of these patients had bladder distention (Fig 5). Another 33% were done by general surgery. Fourteen percent of these had bladder distention. Cardiothoracic, neurology ophthalmology, orthopedics, peripheral vascular, plastic surgery, and urology made up the other 33%. The percentage of bladder distention ranged from 18% to 29%. Seventy percent of all surgeries were done under

general anesthesia. Sixteen percent of these had bladder distention (Fig 6). The other 30% of surgeries were done under spinal, block, or MAPS. Twenty-six percent of these had bladder distention. The mean bladder volume was 274.28 mL, with a standard deviation of 170.92 mL. Ninety-six (19.4%) of the patients had postoperative bladder volume measurements greater than 400 mL, with 54 (11%) patients requiring intermittent straight catheterization. DISCUSSION

This process improvement project provided strong support that the revised bladder protocol incorporating the bladderscan technology was more

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Amount Received

LmTotal

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1751-2000 2001-2250 225%2500

2501-2750

Fig 3.

Fluid received in OR

versus bladder volume.

WARNER ET AL

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70 = 60

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t

30

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10

19-25

26-30

31-35

36-40

41-45

46-50

51-55

56-60 81-65 66-70 Age of Patients

71-75

76-60

51-85

86-90

91-95 96-100

Fig4. Age versus bladder vol-

[llTotal ~<400mL B>400mL 1

effective in identifying postoperative bladder distention than manual palpation. During 1997, when the bladder protocol was used, 1.4% of the PACU patients were thought to have a distended bladder. During the 9 months of data collection, 19.4% of the patients were determined to have postoperative bladder distention. Neither the amount of intravenous fluids received during surgery nor the patient's age correlated strongly with the bladder volume. The length of surgery had the highest Pearson correlate coefficient. However, this correlation was weak, at 0.149. These results were unexpected and contradicted previous beliefs. There was not a significant difference among surgery services or among anesthesia given. Sur-

ume.

gery services ranged from 14% to 29% for bladder distention, with a mean of 22.44 and a standard deviation of 5.07. Anesthesia varied from 16% to 29%. The mean was 24.25, with a standard deviation of 5.91. Both means are close to the actual 19.4% of the patients in the study who had bladder distention.

Weaknesses of the Project The lack of correlation may have occurred because a preoperative bladder ultrasonography was not done. Some patients' bladders may not have been completely empty before surgery. Also, patients continued to receive intravenous fluid in the PACU during the first hour of stay, when the

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160 140 120 100 80 60 40 20 O

i Fig 5. Surgery service versus bladder volume.

Ill/~~ SeTvice I% >40OraL)

[ImTomiEt< 400rnL B> 40Oral I

/

POSTOPERATIVE BLADDER DISTENTION

25

250

General (16%)

Fig 6. Anesthesia versus bladder volume.

p o s t o p e r a t i v e u l t r a s o n o g r a p h y was p e r f o r m e d . Therefore, the intravenous fluid amounts are not exact. In a future project, a preoperative ultrasound should be done, and all intravenous fluids g i v e n before the scan should be recorded, not only the intraoperative fluid. This process i m p r o v e m e n t project has c h a n g e d the practice of postoperative bladder distention detection in our PACU. With the use of bladder ultrasonography and the new bladder protocol,

Spinal (24%) Block (29%) Typeof Anelthella (% >40OraL)

MAPS (28%)

[==Total r~<400rnL B>4OOrnL1

p o s t o p e r a t i v e bladder distention will be m o r e accurately detected and treated appropriately. REFERENCES

l. Kemp D, Tabaka N: Postoperative urinary retention: Part I--Overview and implications for the postanesthesia care unit nurse. J Post Anesth Nurs 5:338-341, 1990 2. Chan H: Noninvasive bladder volume measurement. J Neurosci Nurs 25:309-312, 1993 3. Williams M, Wallhagen M. Dowling G: Urinary retention in hospitalized elderly women. J Gerontol Nuts February: 7 14, 1993