Post-Operative Urinary Retention (POUR) in Thoracic Surgery Patients Receiving Prophylactic Tamsulosin
Phase: PHASE4
Conditions: Thoracic Diseases, Urinary Retention
Sponsor: University of Massachusetts, Worcester

Title: Post-Operative Urinary Retention (POUR) in Thoracic Surgery Patients Receiving 
Prophylactic Tamsulosin 
NCT NUMBER: NCT04994431 
LAST APPROVED/DOCUMENT DATE: 6 SEPTEMBER 2024 
 
 
 

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1. TITLE 
Post-Operative Urinary Retention (POUR) in Thoracic Surgery Patients Receiving Prophylactic 
Tamsulosin 
2. EXTERNAL IRB REVIEW HISTORY* 
NA 
3. PRIOR APPROVALS: 
NA 
Conflict of Interest (COI): The investigators have nothing to disclose 
Biohazardous Agents: NA 
Radiation: NA 
4. OBJECTIVES* 
Post-Operative Urinary Retention (POUR) in Thoracic Surgery is a prospective 
interventional study aiming to test the hypothesis that the prophylactic use of tamsulosin prior to 
thoracic surgery in high-risk patients leads to reduced rates of POUR. Urinary retention is defined 
as eight hours without void after Foley catheter removal and symptoms or bladder volume greater 
than 600cc. 
5. BACKGROUND* 
Post-operative urinary retention (POUR) is one of the most common post-operative 
complications encountered by most surgical specialties. The incidence of POUR can vary from 
five to 70%.1 POUR associated factors reported in the literature include type of anesthesia, type 
and duration of surgery, underlying comorbidities, as well as medicines used in perioperative 
period. The development of  POUR can increase the length of hospitalization and lead to 
significant morbidities such urinary tract infection, detrusor muscle dysfunction, delirium, cardiac 
arrhythmias among others.1 

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POUR definition in the literature is not homogeneous, and include >200mL by bladder 
scanner 4 hours post-op, >500mL by bladder scanner 8 hours post-catheter removal, and >600mL 
by bladder scanner 4 hours after removal of indwelling urinary catheter. 2–4  Urinary retention is 
defined in the current study as eight hours without void after Foley catheter removal and symptoms 
or bladder volume greater than 600 cc. 
There are a limited number of studies available regarding POUR after thoracic surgery, 
and among those, the results vary. In addition, there is continued discussion regarding the 
appropriate time to remove a urinary catheter post-op to prevent or reduce POUR. Early removal 
increases the risk for urinary retention, but late removal increases the risk for acquiring a catheter-
related UTI 5. Although it is currently mandated to remove the urinary catheter 48 hours post-op, 
studies have looked at whether they can be removed earlier without increasing the risk for 
catheterization. Results of the current published studies are conflicting. Chia, et al compared 
patients who underwent transurethral catheter removal on the first post-op day with those who had 
removal after discontinuing patient-controlled epidural anesthesia, usually on the third post-op 
day. Patients in both groups did not require re-catheterization for retention or suffer from catheter-
associated UTIs. However, not surprisingly, catheter-induced urethral pain was higher in the group 
that underwent later removal. The authors therefore concluded that removal of bladder catheter as 
early as post-op day one is preferable due to no difference in UTIs or re-catherization as well as 
decreased urethral pain (2009)6. Other studies noted that earlier removal did not increase the risk 
for POUR and subsequent re-catheterization___0 but was associated with decreased risk for UTIs 
(4,2). On the contrary, Zaouter, et al defined a correlation between early removal and increased 
POUR and re-catherization 7. 
The role of prophylactic tamsulosin administration in prevention of POUR has been 
investigated across various surgical subspecialties. Results of these studies are also mixed. In 
patients undergoing urologic procedures including varicocelectomy, inguinal herniorrhaphy, and 
scrotal surgery, POUR was significantly lower in the group who received tamsulosin (5.9%) 
compared to the placebo group (21.2%) 8. However, there was no difference in POUR rates in 
patients who underwent spinal surgery or colorectal surgery 9,10.  
Although there are varying data across studies measuring POUR after thoracic surgery, 
there are several risk factors that have consistently been identified that predispose patients to 
increased risk of POUR after thoracic surgery: age above 40 years, male, diabetes, and BPH 11. 

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The age cutoff is debatable, but in general, it is accepted that older age correlates with numerous 
types of bladder dysfunction 6. There are also certain procedures within thoracic surgery that 
increase the risk. Lung resection surgery resulted in the highest rate of POUR compared to other 
procedures like sympathicotomies, pleural biopsies, and mediastinal procedures 1. In a review of 
all UMass Memorial patients who underwent thoracic surgery in 2019, the group with the highest 
incidence of POUR consisted of males above the age of 60 who underwent major thoracic 
resections.  The rate in this cohort was as high as 21%.  Although tamsulosin was designed and 
used to treat patients with symptomatic BPH, we would like to study the effect of prophylactic 
tamsulosin in the group of patients with the highest likelihood to develop POUR in an effort to 
prevent this complication. 
Post-operative urinary retention is a prevalent complication.  Patients who undergo thoracic 
surgery have greater urinary retention rates compared to others. Data on effective methods to 
reduce the risk of POUR in this high-risk group are limited. 
 
6. INCLUSION AND EXCLUSION CRITERIA* 
Inclusion criteria:  
- 
All male patients >=60 years old undergoing inpatient thoracic surgery for major 
resections. 
Exclusion criteria:  
- 
Prisoners  
- 
Adults unable to consent  
- 
End stage renal disease on hemodialysis  
- 
Indwelling urinary catheter  
- 
Child-Pugh class C hepatic failure 
- 
Usage of the following medications prior to surgery: strong CYP 3A4 inhibitors, other 
alpha-adrenergic blocking agents. 

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- 
patients known to be CYP2D6 poor metabolizers 
- 
History of prostatectomy or cystectomy  
- 
Patients with contraindications to tamsulosin and those at high risk for side effects: 
hypersensitivity to tamsulosin HCl or any component of FLOMAX capsules,5 
hypersensitivity to sulfonamides.  History of known glaucoma, hypotension, plan to 
undergo cataract surgery in the next 2 weeks 
7. STUDY-WIDE NUMBER OF SUBJECTS* 
NA 
8. STUDY-WIDE RECRUITMENT METHODS* 
NA 
9. STUDY TIMELINES* 
The study will be conducted for twenty-four months from July 2021 – December 2023. The 
study subjects will be enrolled on an ongoing basis and will include all that fulfill the eligibility 
criteria. 
10. STUDY ENDPOINTS* 
See #4  
11. PROCEDURES INVOLVED* 
There will be no randomization process as this is a single arm trial. The patients will first 
provide consent to the research when they visit the clinic or in an inpatient setting. As part of the 
screening process, a physician (or physician’s assistant or nurse practitioner) will review the 
patient’s medication list for potential drug-drug interactions with tamsulosin, make a clinical 
decision regarding the safety of study participation, and document that this screening has occurred. 

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Since visits are being done remotely, study medication will be mailed to the subject’s home 
and a study staff member will call to answer any questions they may have on how to take the 
medication. Otherwise, the medications will be dispensed in person by IDS to a research 
coordinator. The research coordinator will then give the medication  to the patient at the time of 
their Pre-surgical evaluation at the Memorial campus anesthesia clinic. 
Starting 2 days before surgery, patients will receive 0.4 mg Tamsulosin nightly, then on the 
day of surgery, 0.4 mg in holding area, and any additional consecutive days if they experience 
retention, which is the standard of care for all patients that present with POUR. The minimum 
number of days a subject could be on the study drug is 3. Tamsulosin is FDA approved and is 
predominantly used to treat the signs and symptoms of benign prostatic hyperplasia. 
The data collection includes identification of patient and operation characteristics that 
correlate with development of POUR. Some of the factors we propose to study include age, 
operating time, type of surgery, indication for surgery, presence of epidural, development of other 
postoperative complications. Patients’ names will be de-identified with a unique identifier and will 
be paired with the corresponding MRN. Principal Investigator and research coordinator will have 
access to those identifiers. 
 
12. DATA AND SPECIMEN BANKING* 
NA 
13. DATA ANALYSIS AND MANAGEMENT * 
Hypothesis: Prophylactic tamsulosin decreases the rate of postoperative urinary retention 
(POUR) rates in patients undergoing thoracic surgery  
• Primary aim: compare the rates of POUR in thoracic surgery patients treated with preop 
tamsulosin with historic controls. 

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The rates of POUR for major procedures in UMass Thoracic service in the target population 
(male over 60 years old) varied from 8.3% to 33.3% over the last 5 years. In the overall thoracic 
population, this number was in average 8.4% and it varied from 4.3% to 9.3%. 
When analyzing all major procedures performed in the 2019, 48 were performed in males 
over 60 years old, the study target population. The POUR rate was 33.3%. After applying the 
exclusion criteria on those 48 individuals, we found an exclusion rate of 33.3% where 16 
individuals were excluded, 8 for using Flomax prior to surgery and 8 for using one of the following 
medications: 
Buproprion 
Fluconazole, 
TMP-SMX, 
Silodosin, 
Paroxetine 
Terazosin, 
Levofloxacin, Prazosin, Fluoxetine, Sildenafil.  
The overall POUR rate was 33% and among the 32 eligible individuals, POUR rate was 28%. 
Power Calculation 
The incidence rate of 28% was used to estimate the possible scenarios of sample and power 
of analysis presented in Error! Reference source not found..  
The number needed to treat is 60 assuming an 80% reduction of POUR with a power of 
80%.  Assuming the same volume of operations and taking into account the number excluded due 
to exclusion criteria (33%), and refusal rate of 25%, we expect to accrue 24 patients per year and 
achieve the number needed to treat (n=60) in 2.5 years. 
All patients who fulfill the eligibility criteria and thus may benefit from the intervention (use 
of Tamsulosin pre-operatively) will be invited to participate in the study. (Error! Reference 
source not found.) 
Table 1. Sample calculation and power-analysis in three hypothetical scenarios of varying effects 
of tamsulosin  
 
Hypothetical POUR  
Incidence in Intervention Group 
(%) 
N* 
Post-hoc 
Power 
estimate (I) 
Tamsulosin intervention Group effect 1 (reduction of 50%) 
14 
150 
49.3% 
Tamsulosin intervention Group effect 2 (reduction of 80%) 
5.6 
60 
80.4% 
Tamsulosin intervention Group effect 3 (reduction of 90%) 
2.8 
32 
80.4% 
*N of male over 60 years old that undergo to in-patient procedures (I) https://clincalc.com/stats/SampleSize.aspx 

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(II) https://jongguri.shinyapps.io/samplepower/ 
 
The study selected parameters are:  
• Incidence, group historical control 2019 – 28% 
• Incidence (expected), intervention with Tamsulosin – 5.6% (reduction of 80% in 
incidence 
• Subjects, group control – 32 individuals 
• Subjects, group intervention (expected) -60 individuals 
• Alpha - 0.05 
It is expected that the population undergoing thoracic services are similar over time and it 
will be appropriate to use historical controls to compare with the intervention group. 
Our analytical plan is to test the proportion of POUR within the study population comparing 
with the historical controls. The data quality will be monitored by monthly verification of the 
completeness of the data, missing values and accurateness of the variables collected. 
If a statistically significant reduction in POUR rates is observed before the end of the study, 
the study will stop and Tamsulosin will be adopted as prophylaxis for this high-risk population in 
thoracic surgery division. If the benefit is not observed with the estimated sample, the study will 
be reassessed. 
14. PROVISIONS TO MONITOR THE DATA TO ENSURE THE SAFETY OF SUBJECTS* 
We will analyze the patients’ outcomes every 2 months and monitor them for possible side 
effects associated with tamsulosin: hypotension, insomnia, decreased libido, nausea, diarrhea and 
dizziness. 
15. WITHDRAWAL OF SUBJECTS WITHOUT THEIR CONSENT* 
NA 
16. RISKS TO SUBJECTS* 

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The primary risks to the participants include the side effects associated with tamsulosin: 
hypotension, insomnia, decreased libido, nausea, diarrhea and dizziness.  
17. POTENTIAL DIRECT BENEFITS TO SUBJECTS* 
The primary direct benefit to the participants includes decreased urinary retention post-
operatively, which is one of the most common and uncomfortable complications many patients 
face. Decreased urinary retention will also decrease the need for potential re-catheterization. It is 
difficult to accurately predict the probability of this benefit because results vary depending on the 
type of surgery and pre-operative risks; however, several studies have documented the successes 
of prophylactic tamsulosin. 1,12–14 
18. VULNERABLE POPULATIONS* 
NA 
19. MULTI-SITE RESEARCH* 
NA 
20. COMMUNITY-BASED PARTICIPATORY RESEARCH* 
NA 
21. SHARING OF RESEARCH RESULTS WITH SUBJECTS* 
The dissemination of the research results will be performed through interim reports, 
presentations for the UMass Memorial Health Care and UMass Medical School health 
professionals. Scientific abstracts and papers will focus on sharing the results with the scientific 
community. As a very relevant topic, it is intended to disseminate the results beyond the scientific 
community, with the appropriate materials and language (flyers and fact sheets) to the policy 
makers, health care professionals and overall population, including the subjects that took part in 
the study. Individual results will be shared with the subjects if requested. 
22. SETTING 

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The research will solely take place at UMMHC Memorial Campus.  
23. RESOURCES AVAILABLE 
In this study, we assemble the following research team: three thoracic surgeons, one of them 
being the principal investigator (PI); statistician and six research assistants from UMass Medical - 
medical students, residents, fellows or other healthcare providers pool. The roles will be as follows: 
Principal Investigator/thoracic surgeon: Recruit subjects, perform minimally invasive 
thoracic surgery, and prescribe tamsulosin according to procedures described in section #11. She 
will also help analyze the data. Five percent of the PI’s time will be dedicated to the project.  The 
PI is a fellowship trained thoracic surgeon with a Master’s degree in Biostatistics and Patient 
Oriented Research.  She has published many studies focused on surgical patient-oriented 
outcomes.  
Thoracic surgeons (2 other thoracic surgeons in the division of Thoracic Surgery): Recruit 
subjects. Perform minimally invasive thoracic surgery and prescribe tamsulosin according to 
procedures described in section #11. Provide preop and post-operative care for patients. 
Research assistants: describe the study and consent subjects. Query subjects on potential 
adverse effects of tamsulosin. Perform data collection that will be supervised by the PI and 
statistician. They will have CITI training and be a trained University of Massachusetts health care 
provider, such as nurse, medical student, resident, or fellow. 
Statistician and research coordinator: Analyze the data monthly for quality purposes and at 
the time of study conclusion. Assist in research protocol development and oversee data collection. 
24. LOCAL RECRUITMENT METHODS 
Potential subjects will be identified and recruited when they visit the clinic, and the thoracic 
surgeons will ask them permission for the study staff to approach.  Each clinician on the study 
team will only invite their own patients to participate in the study. In addition, inpatients who 
require the appropriate surgeries will also be identified by thoracic surgeons.  

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Individuals who are eligible for the research study will be adult men >60 years old who need 
to undergo some type of thoracic surgery procedure (See #6 for more detailed inclusion criteria). 
The patients’ names and MRN will be recorded electronically, and the patients’ names will be 
replaced by a code. The identifiers will be destroyed after 6 years after the study completion. 
Identifiers will not be recorded for patients who are ineligible or those who decline to participate. 
Recruitment will be done during clinic visit or in UMass Memorial Hospital. Advertisements 
and other recruitment materials including flyers, emails, and letters will not be utilized. There will 
be no payments to the subjects. 
25. LOCAL NUMBER OF SUBJECTS 
Considering the volume of procedures in 2019 of 48 procedures is maintained over time, it 
is estimate that we will be able to enroll 60 patients within 2.5 years. This sample size would allow 
detection of 80% reduction in POUR with a power of 80%. This number of subjects considers a 
refusal rate of 25% and exclusion rate of 33%. 
26. CONFIDENTIALITY  
The data will be stored electronically at UMass Memorial Healthcare share drive. The 
patients’ names will be coded and paired with the corresponding MRN. All of the staff involved 
are HIPPA trained and are part of the UMass Memorial Healthcare/UMass Medical School. 
27. PROVISIONS TO PROTECT THE PRIVACY INTERESTS OF SUBJECTS 
Screening for eligibility and discussion of the research will take place when the patients visit 
the clinic. Patients who enroll prospectively will be asked to provide signed Authorization. For 
subjects who serve as historical controls, HIPAA waiver of authorizations will be used. 
Data will be abstracted by the thoracic surgery data manager in a secure server and stored on 
the thoracic surgery shared drive password-protected hard drive provided by UMass Memorial 
Health Care. Any hard copies of data will be stored in a locked office in Thoracic Surgery. The 
system hosted locally by UMass Memorial Health Care and employs user authentication and role-
based security. Web-based data entry is via an SSL cryptographic transport protocol. Additional 

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security procedures are in place for data access. The environment logs are audited by Information 
Services (IS). Any additional data collection needed will be performed in RedCap and stored in 
the thoracic protected drive. 
The PI and research team will take all the recommended steps to protect all personal 
information. After the matching and database creation, the individuals will be assigned a unique 
code in order to de-identify the data. Only the PI and the data manager analyst assigned for the 
project and will have access to the code list, which contains the information necessary to re-identify 
the data. All data are kept confidential and accessible only to researchers on this study. The paper 
documents will be secured and shredded after six years of the end of the study. The electronic de-
identified database will NOT be destroyed and will be maintained in a secure host at the secure 
drive. The coded list will be destroyed using secure deletion utility after six years after the end of 
the study. 
28. COMPENSATION FOR RESEARCH-RELATED INJURY 
NA 
29. ECONOMIC BURDEN TO SUBJECTS 
There will be no costs associated with the use of Tamsulosin under this study. The study will 
cover the costs of the medication given to subjects. The ultrasound used for post void residual 
measurement will be provided by the Thoracic Surgery Division. For all patients who agree to 
participate in the prospective trial, measurements will be done by a research assistant at no cost to 
the patient.  This study was approved for a quality improvement grant under the UMass Memorial 
Health Care. 
30. CONSENT PROCESS 
In order to ensure that all study staff are familiar with and will follow HRP-802 Investigator 
Guidance, all the team members will have a discussion joint on the components of the form. During 
this time, any questions or confusion will be addressed. The consent process and discussion of the 
research will occur during the clinic visit prior to the surgery. There will be no waiting period 
between recruitment and obtaining consent, since both will occur at the same time during the clinic 

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visit. In order to ensure ongoing consent, we will ask the patients again during the last visit prior 
to their surgery if they would still like to participate in the research.  
To obtain informed consent from non-English speaking subjects, the informed consent will 
be translated in Spanish and Portuguese. If needed, any information can be clarified by using phone 
interpreter services. 
31. PROCESS TO DOCUMENT CONSENT IN WRITING 
We will be obtaining consent in writing. In order to ensure that all study staff are familiar 
with and will follow HRP-803 Investigator Guidance, all the team members will discuss the 
components of the form. During this time, any questions or confusion will be addressed. The 
consent will predominantly be obtained by the research assistants on the team. 
During the COVID -19 pandemic, surgical discussions are being conducted virtually.  It is 
therefore not feasible to obtain written consent from the subject in person.  During their telehealth 
visit, potential subjects will be informed of the study and offered the option to participate.  The 
study will be explained to them in detail and all questions will be answered.  If they are interested, 
two consents will be sent to them either by standard mail, with a self-addressed stamped envelope 
to return the signed consent or electronically with the option of returning a signed copy 
electronically or by standard mail.   
32. DRUGS OR DEVICES 
Patients will take 0.4 mg tamsulosin for two evenings prior to surgery as well as the day of 
surgery prior to the operation.  The medication will be dispensed from IDS. According to the HRP-
42515, and the FDA Guidelines16,17, the study drug, Tamulosin fulfills the following criteria, and 
thus is exempt of IND. 
• Determination: The drug is lawfully marketed in the United States 
• Determination: The investigation does not involve a route, dosage level, or use in a patient 
population or other factor that significantly increases the risks (or decreases the 
acceptability of the risks) associated with the use of the drug product 

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• Determination: Evidence of FDA approval and FDA-approved indications is in the 
protocol file 
The project obtained from Food Drug Administration the IND exemption ref PIND 148434 
 
 

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Kim KW, Lee J-I, Kim JS, Lee Y-J, Choi W-J, Jung H, et al. Risk factors for urinary 
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Tripepi-Bova KA, Sun Z, Mason D, Albert NM. Early Removal of Urinary Catheters in 
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Chia Y-Y, Wei R-J, Chang H-C, Liu K. Optimal duration of urinary catheterization after 
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Madani AH, Aval HB, Mokhtari G, Nasseh H, Esmaeili S, Shakiba M, et al. Effectiveness 
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13.  Chapman GC, Sheyn D, Petrikovets A, Mahajan ST, El-Nashar S, Pollard R, et al. 
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https://www.umassmed.edu/globalassets/ccts/ccts-media/irb/updated-worksheets-2015/hrp-
425-worksheet---drugs_21jan19.pdf 
16.  Investigational New Drug Applications (INDs) — Determining Whether Human Research 
Studies Can Be Conducted Without an IND. 2019;23.  
17.  Food and Drug Administration (FDA). Tamsulosin hydrochloride - Label. 2019.