Postoperative Bladder Filling After Outpatient Laparoscopic Hysterectomy and Time to Discharge: a Randomized Controlled Trial
Phase: NA
Conditions: Patient Discharge, Urinary Complication
Sponsor: University of Tennessee

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Postoperative Bladder Filling After Outpatient Laparoscopic Hysterectomy and Time to 
Discharge: A Randomized Controlled Trial 
NCT Number: Not Yet Assigned 
Document Date: 12/3/2024 
 
 

Study Protocol 
 
We will be evaluating the effects of backfilling the bladder on time to void and time to discharge 
from the post-anesthesia care unit (PACU) in patients undergoing laparoscopic hysterectomy.  
A randomization scheme using a block size of four will be generated. Sealed randomization 
envelopes will be opened for each subject after anesthesia is initiated in the operating suite. This 
study will be single-blinded to the participant. After group allocation, the surgeon will be 
informed of whether or not the bladder will be backfilled at the completion of the surgery prior 
to Foley catheter removal. If the patient is assigned to group A, 200 mL of room temperature, 
sterile normal saline will be instilled retrograde into the bladder at the completion of surgery 
prior to Foley catheter removal and the Foley subsequently removed intraoperatively. If the 
patients is assigned to group B, the Foley catheter will be removed intraoperatively at completion 
of the procedure. Our standard protocol is to use a 16F Foley catheter for gynecologic 
laparoscopy cases and patients from both groups will receive the same size catheter. Two 
hundred mL of sterile saline will be chosen as the amount to backfill to prevent postoperative 
overdistension as the patient will continue to naturally produce urine while in the recovery room 
awaking from anesthesia.  
We used historical controls to determine our time to discharge and then calculated an adequate 
sample size for our primary outcome, time to discharge, with a clinically relevant 30-minute 
difference.  
Information will be collected about narcotics receiving during the surgical procedure, as this may 
affect urinary retention rates. In addition, the following information will be collected: patient 
demographics, such as age, race, ethnicity, insurance status, BMI; health history: medical 
comorbidities, surgical history, preoperative medications, history of bladder problems, history of 
neurologic problems, history of chronic pain, and tobacco use; procedure: indication for 
procedure, benign/malignant pathology, time to discharge, time to void, urine output, need to go 
home with foley catheter, intraoperative urinary tract injury, intraoperative narcotics 
administration, surgical complications, estimated blood loss, intraoperative/postoperative IV 
fluids, postoperative opioid use, and postoperative UTI.  
If a subject is unable to void, they will be admitted overnight and observed for repeat trial of 
voiding.  
Adverse events will be monitored and collected through the Day 30 visit, to include the 
following categories: Death, Life-threatening, Hospitalization (initial or prolonged), Disability or 
Permanent Damage, Required Intervention to Prevent Impairment or Damage (Devices), Other 
systems, with specific focus on bladder irritation or discomfort.  
 
Statistical Analysis Plan 
 
We have estimated a necessary sample size of 56 participants per group (112 total) with an 
anticipated effect size of 0.52 based on expected means of 172 minutes to discharge for the 
experimental arm (SD 58 minutes) and 202 minutes to discharge for the control arm (SD 58 
minutes), accounting for expected loss to follow up of 10%. Patients will be randomized using 
14 block groups of size 8 each.  
We will provide a table of demographic and clinical characteristics by assigned group. For 
continuous variables, we will provide means and standard deviations per group, applying a t-test 

for comparison of independent means. For categorical variables, we will provide counts and 
percentages, applying chi-square test for comparison of proportions.  
We will develop a time-to-event analysis for time to discharge including Kaplan-Meier curves by 
assigned group and multivariable Cox proportional hazard models.