Postoperative urinary retention:Risk factors, bladder filling rate and time to catheterization: an observational study as part of a randomized controlled trial

Background: Knowledge of risk factors for postoperative urinary retention may guide appropriate and timely urinary catheterization. We aimed to determine independent risk factors for postoperative urinary catheterization in general surgical patients. In addition, we calculated bladder filling rate and assessed the time to spontaneous voiding or catheterization. We used the patients previously determined individual maximum bladder capacity as threshold for urinary catheterization.Methods: Risk factors for urinary catheterization were prospectively determined in 936 general surgical patients. Patients were at least 18 years of age and operated under general or spinal anesthesia without the need for an indwelling urinary catheter. Patients measured their maximum bladder capacity preoperatively at home, by voiding in a calibrated bowl after a strong urge that could no longer be ignored. Postoperatively, bladder volumes were assessed hourly with ultrasound. When patients reached their maximum bladder capacity and were unable to void, they were catheterized by the nursing staff. Bladder filling rate and time to catheterization were determined.Results: Spinal anesthesia was the main independent modifiable risk factor for urinary catheterization (hyperbaric bupivacaine, relative risk 8.1, articaine RR 3.1). Unmodifiable risk factors were a maximum bladder capacity &lt;500 mL (RR 6.7), duration of surgery &gt;= 60 min (RR 5.5), first scanned bladder volume at the Post Anesthesia Care Unit &gt;= 250mL (RR 2.1), and age &gt;= 60 years (RR 2.0). Urine production varied from 100 to 200 mL/h. Catheterization or spontaneous voiding took place approximately 4 h postoperatively.Conclusion: Spinal anesthesia, longer surgery time, and older age are the main risk factors for urinary retention catheterization. Awareness of these risk factors, regularly bladder volume scanning (at least every 3 h) and using the individual maximum bladder capacity as volume threshold for urinary catheterization may avoid unnecessary urinary catheterization and will prevent bladder overdistention with the attendant risk of lower urinary tract injury.</p

Non-invasive bladder volume measurement for the prevention of postoperative urinary retention:validation of two ultrasound devices in a clinical setting

Ultrasound scanning of bladder volume is used for prevention of postoperative urinary retention (POUR). Accurate assessment of bladder volume is needed to allow clinical decision-making regarding the need for postoperative catheterization. Two commonly used ultrasound devices, the BladderScan (R) BVI 9400 and the newly released Prime (R) (Verathon Medical (R), Bothell, WA, USA), with or without the pre-scan' option, have not been validated in clinical practice. The aim of this study was to assess the performance of these devices in daily clinical practice. Between June and September 2016 a prospective observational study was conducted in 318 surgical patients (18years or older) who needed a urinary catheter perioperatively for clinical reasons. For acceptable performance, we required that the volume as estimated by the BladderScan (R) differs by no more than 5% from the actual urine volume after catheterization. The Schuirmann's two one-sided test was performed to assess equivalence between the BladderScan (R) estimate and catheterization. The BVI 9400 (R) overestimated the actual bladder volume by +17.5% (95% CI +8.8 to +26.3%). The Prime (R) without pre-scan underestimated by -4.1% (95% CI -8.8 to +0.5%) and the Prime (R) with pre-scan underestimated by -6.3% (95% CI -11.6 to -1.1%). This study shows that while both ultrasound devices were able to approximate current bladder volume, both BVI 9400 (R) and Prime (R) with and without pre-scanwere not able to measure the actual bladder volume within our predefined limit of +/- 5%. Using the pre-scan feature of the Prime (R) did not further improve accuracy

Driving pressure during general anesthesia for open abdominal surgery (DESIGNATION) : study protocol of a randomized clinical trial

Background Intraoperative driving pressure (Delta P) is associated with development of postoperative pulmonary complications (PPC). When tidal volume (V-T) is kept constant, Delta P may change according to positive end-expiratory pressure (PEEP)-induced changes in lung aeration. Delta P may decrease if PEEP leads to a recruitment of collapsed lung tissue but will increase if PEEP mainly causes pulmonary overdistension. This study tests the hypothesis that individualized high PEEP, when compared to fixed low PEEP, protects against PPC in patients undergoing open abdominal surgery. Methods The "Driving prESsure durIng GeNeral AnesThesIa for Open abdomiNal surgery trial" (DESIGNATION) is an international, multicenter, two-group, double-blind randomized clinical superiority trial. A total of 1468 patients will be randomly assigned to one of the two intraoperative ventilation strategies. Investigators screen patients aged >= 18 years and with a body mass index <= 40 kg/m(2), scheduled for open abdominal surgery and at risk for PPC. Patients either receive an intraoperative ventilation strategy with individualized high PEEP with recruitment maneuvers (RM) ("individualized high PEEP") or one in which PEEP of 5 cm H2O without RM is used ("low PEEP"). In the "individualized high PEEP" group, PEEP is set at the level at which Delta P is lowest. In both groups of the trial, V-T is kept at 8 mL/kg predicted body weight. The primary endpoint is the occurrence of PPC, recorded as a collapsed composite of adverse pulmonary events. Discussion DESIGNATION will be the first randomized clinical trial that is adequately powered to compare the effects of individualized high PEEP with RM versus fixed low PEEP without RM on the occurrence of PPC after open abdominal surgery. The results of DESIGNATION will support anesthesiologists in their decisions regarding PEEP settings during open abdominal surgery

Postoperative Bladder Catheterization Based on Individual Bladder Capacity A Randomized Trial

Background: Untreated postoperative urinary retention can result in permanent lower urinary tract dysfunction and can be prevented by timely bladder catheterization. The author hypothesized that the incidence of postoperative bladder catheterization can be decreased by using the patient's own maximum bladder capacity (MBC) instead of a fixed bladder volume of 500 ml as a threshold for catheterization. Methods: Randomized parallel-arm and single-blinded comparative effectiveness trial conducted in 1,840 surgical patients, operated under general or spinal anesthesia without an indwelling urinary catheter. Patients were randomized to either use their individual MBC (index) or a fixed bladder volume of 500 ml (control) as a threshold for postoperative bladder catheterization. Preoperatively, the MBC was determined at home by voiding in a calibrated bowl. All other bladder volumes were measured by ultrasound. Postoperatively, bladder catheterization was performed when spontaneous voiding was impossible, and the ultrasound measurement exceeded the threshold for the group in which the patient was randomized (500 or MBC). The primary outcome was the incidence of bladder catheterization. Results: The average MBC in the control group was 582 ml (199 ml) and in the index group 611 ml (+/- 209 ml). The incidence of catheterization decreased from 11.8% (107 of 909 patients) in the control group to 8.6% (80 of 931) in the index group (relative risk 0.73, 95% CI 0.55 to 0.96, P = 0.025). There were no adverse events in either group. Conclusions: In patients undergoing surgery under general or spinal anesthesia using the MBC rather than a fixed 500 ml threshold for bladder catheterization is a safe approach that significantly reduces the incidence of postoperative bladder catheterizations

Potential Risk and Safety Measures in Laparoscopy in COVID-19 Positive Patients

Background. During the COVID-19 pandemic the question arises if laparoscopy, as an aerosol forming procedure, poses a potential risk for viral transmission of SARS-CoV-2 to healthcare workers. Methods. A literature search was conducted using PubMed, Embase and MEDLINE. Articles reporting information regarding COVID-19 or other relevant viruses and laparoscopy, surgical smoke, aerosols and viral transmission were included. Results. Although aerosols produced during laparoscopy do not originate from the respiratory tract, the main transmission route of SARS-CoV-2, research did show SARS-CoV-2 to be present in other body fluids. The transmission risk via this route is however considered very low. As previous research showed potential viral transmission during laparoscopy for viruses that spread through contaminated body fluids, there might be a potential risk of SARS-CoV-2 transmission during laparoscopy, albeit considered very small. Conclusion. Due to the small risk compared to widely known benefits of laparoscopy, there is no reason to replace laparoscopy by laparotomy due to COVID-19 infection. To avoid the potential small risk of viral transmission, additional safety measures are advised.Medical Instruments & Bio-Inspired Technolog

Non-invasive bladder volume measurement for the prevention of postoperative urinary retention : validation of two ultrasound devices in a clinical setting

Ultrasound scanning of bladder volume is used for prevention of postoperative urinary retention (POUR). Accurate assessment of bladder volume is needed to allow clinical decision-making regarding the need for postoperative catheterization. Two commonly used ultrasound devices, the BladderScan® BVI 9400 and the newly released Prime® (Verathon Medical®, Bothell, WA, USA), with or without the 'pre-scan' option, have not been validated in clinical practice. The aim of this study was to assess the performance of these devices in daily clinical practice. Between June and September 2016 a prospective observational study was conducted in 318 surgical patients (18 years or older) who needed a urinary catheter perioperatively for clinical reasons. For acceptable performance, we required that the volume as estimated by the BladderScan® differs by no more than 5% from the actual urine volume after catheterization. The Schuirmann's two one-sided test was performed to assess equivalence between the BladderScan® estimate and catheterization. The BVI 9400® overestimated the actual bladder volume by + 17.5% (95% CI + 8.8 to + 26.3%). The Prime® without pre-scan underestimated by - 4.1% (95% CI - 8.8 to + 0.5%) and the Prime® with pre-scan underestimated by - 6.3% (95% CI - 11.6 to - 1.1%). This study shows that while both ultrasound devices were able to approximate current bladder volume, both BVI 9400® and Prime®-with and without pre-scan-were not able to measure the actual bladder volume within our predefined limit of ± 5%. Using the pre-scan feature of the Prime® did not further improve accuracy