Development of an ultra mini-oxygenator for use in low-volume, buffer-perfused preparations

Introduction: Small animal models are widely used in basic research. However, experimental systems requiring extracorporeal circuits are frequently confronted with limitations related to equipment size. This is particularly true for oxygenators in systems with limited volumes. Thus we aimed to develop and validate an ultra mini-oxygenator for low-volume, buffer-perfused systems. Methods: We have manufactured a series of ultra mini-oxygenators with approximately 175 aligned, microporous, polypropylene hollow fibers contained inside a shell, which is sealed at each of the two extremities to isolate perfusate and gas compartments. With this construction, gas passes through hollow fibers, while perfusate circulates around fibers. Performance of ultra mini-oxygenators (oxygen partial pressure (PO2 ), gas and perfusate flow, perfusate pressure and temperature drop) were assessed with modified Krebs-Henseleit buffer in an in vitro perfusion circuit and an ex vivo rat heart preparation. Results: Mean priming volume of ultra mini-oxygenators was 1.2±0.5 mL and, on average, 86±6% of fibers were open (n=17). In vitro, effective oxygenation (PO2=400-500 mmHg) was achieved for all flow rates up to 50 mL/min and remained stable for at least 2 hours (n=5). Oxygenation was also effective and stable (PO2=456±40 mmHg) in the isolated heart preparation for at least 60 minutes ("venous" PO2=151±11 mmHg; n=5). Conclusions: We have established a reproducible procedure for fabrication of ultra mini-oxygenators, which provide reliable and stable oxygenation for at least 60-120 min. These oxygenators are especially attractive for pre-clinical protocols using small, rather than large, animals.

Adequacy of an early arterial phase low-volume contrast protocol in 64-detector computed tomography angiography for aortoiliac aneurysms

PURPOSE: This retrospective study was conducted to determine whether a low-volume contrast medium protocol provides sufficient enhancement for 64-detector computed tomography angiography (CTA) in patients with aortoiliac aneurysms. METHODS: Evaluated were 45 consecutive patients (6 women; mean age, 72 +/- 6 years) who were referred for aortoiliac computed tomography angiography between October 2005 and January 2007. Group A (22 patients; creatinine clearance, 64.2 +/- 8.1 mL/min) received 50 mL of the contrast agent. Group B (23 patients; creatinine clearance, 89.4 +/- 7.3 mL/min) received 100 mL of the contrast agent. The injection rate was 3.5 mL/s, followed by 30 mL of saline at 3.5 mL/s. Studies were performed on the same 64-detector computed tomography scanner using a real-time bolus-tracking technique. Quantitative analysis was performed by determination of mean vascular attenuation at 10 regions of interest from the suprarenal aorta to the common femoral artery by one reader blinded to type and amount of contrast agent and compared using the Student t test. Image quality according to a 4-point scale was assessed in consensus by two readers blinded to type and amount of contrast medium and compared using the Mann-Whitney test. Multivariable adjustments were performed using ordinal regression analysis. RESULTS: Mean total attenuation did not differ significantly between both groups (196.5 +/- 33.0 Hounsfield unit [HU] in group A and 203.1 +/- 44.2 HU in group B; P = .57 by univariate and P > .05 by multivariable analysis). Accordingly, attenuation at each region of interest was not significantly different (P > .35). Image quality was excellent or good in all patients. No significant differences in visual assessment were found comparing both contrast medium protocols (P > .05 by univariate and by multivariable analysis). CONCLUSIONS: Aortoiliac aneurysm imaging can be performed with substantially reduced amounts of contrast medium using 64-detector computed tomography angiography technology.

Oxygen-transfer performance of a newly designed, very low-volume membrane oxygenator.

OBJECTIVES Oxygenation of blood and other physiological solutions are routinely required in fundamental research for both in vitro and in vivo experimentation. However, very few oxygenators with suitable priming volumes (<2-3 ml) are available for surgery in small animals. We have designed a new, miniaturized membrane oxygenator and investigated the oxygen-transfer performance using both buffer and blood perfusates. METHODS The mini-oxygenator was designed with a central perforated core-tube surrounded by parallel-oriented microporous polypropylene hollow fibres, placed inside a hollow shell with a lateral-luer outlet, and sealed at both extremities. With this design, perfusate is delivered via the core-tube to the centre of the mini-oxygenator, and exits via the luer port. A series of mini-oxygenators were constructed and tested in an in vitro perfusion circuit by monitoring oxygen transfer using modified Krebs-Henseleit buffer or whole porcine blood. Effects of perfusion pressure and temperature over flows of 5-60 ml × min(-1) were assessed. RESULTS Twelve mini-oxygenators with a mean priming volume of 1.5 ± 0.3 ml were evaluated. With buffer, oxygen transfer reached a maximum of 14.8 ± 1.0 ml O2 × l(-1) (pO2: 450 ± 32 mmHg) at perfusate flow rates of 5 ml × min(-1) and decreased with an increase in perfusate flow to 7.8 ± 0.7 ml ml O2 × l(-1) (pO2: 219 ± 24 mmHg) at 60 ml × min(-1). Similarly, with blood perfusate, oxygen transfer also decreased as perfusate flow increased, ranging from 33 ± 5 ml O2 × l(-1) at 5 ml × min(-1) to 11 ± 2 ml O2 × l(-1) at 60 ml × min(-1). Furthermore, oxygen transfer capacity remained stable with blood perfusion over a period of at least 2 h. CONCLUSIONS We have developed a new miniaturized membrane oxygenator with an ultra-low priming volume (<2 ml) and adequate oxygenation performance. This oxygenator may be of use in overcoming current limitations in equipment size for effective oxygenation in low-volume perfusion circuits, such as small animal extracorporeal circulation and ex vivo organ perfusion.

Oxygen-transfer performance of a newly designed, very low-volume membrane oxygenator

Gebiet: Chirurgie Biomedizintechnik Biophysik Transplantationsmedizin Kardiologie Abstract: OBJECTIVES: – Oxygenation of blood and other physiological solutions are routinely required in fundamental research for both in vitro and in vivo experimentation. However, very few oxygenators with suitable priming volumes (<2-3 ml) are available for surgery in small animals. We have designed a new, miniaturized membrane oxygenator and investigated the oxygen-transfer performance using both buffer and blood perfusates. – – METHODS: – The mini-oxygenator was designed with a central perforated core-tube surrounded by parallel-oriented microporous polypropylene hollow fibres, placed inside a hollow shell with a lateral-luer outlet, and sealed at both extremities. With this design, perfusate is delivered via the core-tube to the centre of the mini-oxygenator, and exits via the luer port. A series of mini-oxygenators were constructed and tested in an in vitro perfusion circuit by monitoring oxygen transfer using modified Krebs-Henseleit buffer or whole porcine blood. Effects of perfusion pressure and temperature over flows of 5-60 ml × min(-1) were assessed. – – RESULTS: – Twelve mini-oxygenators with a mean priming volume of 1.5 ± 0.3 ml were evaluated. With buffer, oxygen transfer reached a maximum of 14.8 ± 1.0 ml O2 × l(-1) (pO2: 450 ± 32 mmHg) at perfusate flow rates of 5 ml × min(-1) and decreased with an increase in perfusate flow to 7.8 ± 0.7 ml ml O2 × l(-1) (pO2: 219 ± 24 mmHg) at 60 ml × min(-1). Similarly, with blood perfusate, oxygen transfer also decreased as perfusate flow increased, ranging from 33 ± 5 ml O2 × l(-1) at 5 ml × min(-1) to 11 ± 2 ml O2 × l(-1) at 60 ml × min(-1). Furthermore, oxygen transfer capacity remained stable with blood perfusion over a period of at least 2 h. – – CONCLUSIONS: – We have developed a new miniaturized membrane oxygenator with an ultra-low priming volume (<2 ml) and adequate oxygenation performance. This oxygenator may be of use in overcoming current limitations in equipment size for effective oxygenation in low-volume perfusion circuits, such as small animal extracorporeal circulation and ex vivo organ perfusion. – – © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Ultrasonographic guided axillary plexus blocks with low volumes of local anaesthetics: a crossover volunteer study

Our study group recently evaluated an ED(95) local anaesthetic volume of 0.11 ml.mm(-2) cross-sectional nerve area for the ulnar nerve. This prospective, randomised, double-blind crossover study investigated whether this volume is sufficient for brachial plexus blocks at the axillary level. Ten volunteers received an ultrasonographic guided axillary brachial plexus block either with 0.11 ('low' volume) or 0.4 ('high' volume) ml.mm(-2) cross-sectional nerve area with mepivacaine 1%. The mean (SD) volume was in the low volume group 4.0 (1.0) and 14.8 (3.8) ml in the high volume group. The success rate for the individual nerve blocks was 27 out of 30 in the low volume group (90%) and 30 out of 30 in the high volume group (100%), resulting in 8 out of 10 (80%) vs 10 out of 10 (100%) complete blocks in the low vs the high volume groups, respectively (NS). The mean (SD) sensory onset time was 25.0 (14.8) min in the low volume group and 15.8 (6.8) min in the high volume group (p < 0.01). The mean (SD) duration of sensory block was 125 (38) min in the low volume group and 152 (70) min in the high volume group (NS). This study confirms our previous published ED(95) volume for mepivacaine 1% to block peripheral nerves. The volume of local anaesthetic has some influence on the sensory onset time.

Sirolimus-eluting stent treatment at high-volume centers confers lower mortality at 6-month follow-up: results from the prospective multicenter German Cypher Registry

BACKGROUND: Studies continue to identify percutaneous coronary intervention procedural volume both at the institutional level and at the operator level as being strongly correlated with outcome. High-volume centers have been defined as those that perform >400 percutaneous coronary intervention procedures per year. The relationship between drug-eluting stent procedural volume and outcome is unknown. We investigated this relationship in the German Cypher Registry. METHODS AND RESULTS: The present analysis included 8201 patients treated with sirolimus-eluting stents between April 2002 and September 2005 in 51 centers. Centers that recruited >400 sirolimus-eluting stent patients in this time period were considered high-volume centers; those with 150 to 400 patients were considered intermediate-volume centers; and those with <150 patients were designated as low-volume centers. The primary end point was all death, myocardial infarction, and target-vessel revascularization at 6 months. This end point occurred in 11.3%, 12.1%, and 9.0% of patients in the low-, intermediate-, and high-volume center groups, respectively (P=0.0001). There was no difference between groups in the rate of target-vessel revascularization (P=0.2) or cerebrovascular accidents (P=0.5). The difference in death/myocardial infarction remained significant after adjustment for baseline factors (odds ratio 1.85, 95% confidence interval 1.31 to 2.59, P<0.001 for low-volume centers; odds ratio 1.69, 95% confidence interval 1.29 to 2.21, P<0.001 for intermediate-volume centers). Patient and lesion selection, procedural features, and postprocedural medications differed significantly between groups. CONCLUSIONS: The volume of sirolimus-eluting stent procedures performed on an institutional level was inversely related to death and myocardial infarction but not to target-vessel revascularization at 6-month follow-up. Safety issues are better considered in high-volume centers. These findings have important public health policy implications.

Supplemental oxygen, but not supplemental crystalloid fluid, increases tissue oxygen tension in healthy and anastomotic colon in pigs

BACKGROUND: Low tissue oxygen tension is an important factor leading to the development of wound dehiscence and anastomotic leakage after colon surgery. We tested whether supplemental fluid and supplemental oxygen can increase tissue oxygen tension in healthy and injured, perianastomotic, and anastomotic colon in an acutely instrumented pig model of anastomosis surgery. METHODS: Sixteen Swiss Landrace pigs were anesthetized (isoflurane 0.8%-1%) and their lungs ventilated. The animals were randomly assigned to low fluid treatment ("low" group, 3 mL x kg(-1) x h(-1) lactated Ringer's solution) or high fluid treatment ("high" group, 10 mL/kg bolus, 18 mL x kg(-1) x h(-1) lactated Ringer's solution) during colon anastomosis surgery and a subsequent measurement period (4 h). Two-and-half hours after surgery, tissue oxygen tension was recorded for 30 min during ventilation with 30% oxygen. Three hours after surgery, the animals' lungs were ventilated with 100% oxygen for 60 min. Tissue oxygen tension was recorded in the last 30 min. Tissue oxygen tension was measured with polarographic Clark-type electrodes, positioned in healthy colonic wall, close (2 cm) to the anastomosis, and in the anastomosis. RESULTS: In every group, tissue oxygen tension during ventilation with 100% oxygen was approximately twice as high as during ventilation with 30% oxygen, a statistically significant result. High or low volume crystalloid fluid treatment had no effect on colon tissue oxygen tension. CONCLUSIONS: Supplemental oxygen, but not supplemental crystalloid fluid, increased tissue oxygen tension in healthy, perianastomotic, and anastomotic colon tissue.

The role of lymphadenectomy in high risk prostate cancer

Historically, patients with high risk prostate cancer were considered poor candidates for radical prostatectomy (RP) due to the likelihood of positive pelvic lymph nodes and decreased long term survival. Although there is still no consensus on the optimal therapy for this group of patients, there is increasing evidence that surgery could play a role. Cancer specific survival (CSS) rates after RP for locally advanced disease at 10 year follow up range from 29 to 72%, depending on tumor differentiation. The role of pelvic lymph node dissection (PLND) in prostate cancer remains a controversial topic. Nonetheless, in conjunction with RRP extended PLND (ePLND) should be performed as extended lymph node dissection in lieu of standard PLND may increase staging accuracy, influence decision making with respect to adjuvant therapy and possibly impact outcome. High risk patients with organ confined prostate cancer and low volume (micro)metastatic disease may be the ones to profit most from this approach.

Pelvic lymph node dissection in prostate cancer

CONTEXT: Pelvic lymph node dissection (PLND) is considered the most reliable procedure for the detection of lymph node metastases in prostate cancer (PCa); however, the therapeutic benefit of PLND in PCa management is currently under debate. OBJECTIVE: To systematically review the available literature concerning the role of PLND and its extent in PCa staging and outcome. All of the existing recommendations and staging tools determining the need for PLND were also assessed. Moreover, a systematic review was performed of the long-term outcome of node-positive patients stratified according to the extent of nodal invasion. EVIDENCE ACQUISITION: A Medline search was conducted to identify original and review articles as well as editorials addressing the significance of PLND in PCa. Keywords included prostate cancer, pelvic lymph node dissection, radical prostatectomy, imaging, and complications. Data from the selected studies focussing on the role of PLND in PCa staging and outcome were reviewed and discussed by all of the contributing authors. EVIDENCE SYNTHESIS: Despite recent advances in imaging techniques, PLND remains the most accurate staging procedure for the detection of lymph node invasion (LNI) in PCa. The rate of LNI increases with the extent of PLND. Extended PLND (ePLND; ie, removal of obturator, external iliac, hypogastric with or without presacral and common iliac nodes) significantly improves the detection of lymph node metastases compared with limited PLND (lPLND; ie, removal of obturator with or without external iliac nodes), which is associated with poor staging accuracy. Because not all patients with PCa are at the same risk of harbouring nodal metastases, several nomograms and tables have been developed and validated to identify candidates for PLND. These tools, however, are based mostly on findings derived from lPLND dissections performed in older patient series. According to these prediction models, a staging PLND might be omitted in low-risk PCa patients because of the low rate of lymph node metastases found, even after extended dissections (<8%). The outcome for patients with positive nodes is not necessarily poor. Indeed, patients with low-volume nodal metastases experience excellent survival rates, regardless of adjuvant treatment. But despite few retrospective studies reporting an association between PLND and PCa progression and survival, the exact impact of PLND on patient outcomes has not yet been clearly proven because of the lack of prospective randomised trials. CONCLUSIONS: On the basis of current data, we suggest that if a PLND is indicated, then it should be extended. Conversely, in view of the low rate of LNI among patients with low-risk PCa, a staging ePLND might be spared in this patient category. Whether this approach is also safe from oncologic perspectives is still unknown. Patients with low-volume nodal metastases have a good long-term prognosis; to what extent this prognosis is the result of a positive impact of PLND on PCa outcomes is still to be determined.

Tunnelled versus straight intravitreal injection: intraocular pressure changes, vitreous reflux, and patient discomfort

PURPOSE: To compare tunnelled scleral intravitreal injection with straight scleral intravitreal injection concerning short-term intraocular pressure (IOP) changes, occurrence and amount of vitreous reflux, and patient discomfort. METHODS: Sixty patients were randomly allocated to two groups (tunnelled intravitreal injection and straight intravitreal injection). IOP was measured before and directly (<1 minute) after the injection of 0.05 mL of an antivascular endothelial growth factor agent and then every 5 minutes until IOP was <30 mmHg. Occurrence and amount of vitreous reflux were recorded. Patient discomfort during injection was assessed with a Wong-Baker faces pain rating scale. RESULTS: IOP (mmHg +/- SD) increased significantly directly after injection to 35.97 +/- 8.13 (tunnelled intravitreal injection) and 30.19 +/- 12.14 (straight intravitreal injection). These pressure spikes differed significantly between both groups (P = 0.01, mean difference: -7.11). Five minutes after injection, there was no significant difference in IOP increase between the groups. All IOP measurements were <30 mmHg after 15 minutes. Occurrence and amount of vitreous reflux were significantly higher with straight intravitreal injection. There was no significant difference in Wong-Baker faces pain rating scale score between both groups. CONCLUSION: Tunnelled intravitreal injection seems to be the technique of choice for low-volume intravitreal injection (0.05 mL). There is neither a difference in patient discomfort nor a difference in IOP increase 5 minutes after injection between both groups. Significantly less vitreous reflux with tunnelled intravitreal injection should lead to less postinjectional drug loss.

Restrictive deferred hydration combined with preemptive norepinephrine infusion during radical cystectomy reduces postoperative complications and hospitalization time: a randomized clinical trial.

BACKGROUND Anesthetics and neuraxial anesthesia commonly result in vasodilation/hypotension. Norepinephrine counteracts this effect and thus allows for decreased intraoperative hydration. The authors investigated whether this approach could result in reduced postoperative complication rate. METHODS In this single-center, double-blind, randomized, superiority trial, 166 patients undergoing radical cystectomy and urinary diversion were equally allocated to receive 1 ml·kg·h of balanced Ringer's solution until the end of cystectomy and then 3 ml·kg·h until the end of surgery combined with preemptive norepinephrine infusion at an initial rate of 2 µg·kg·h (low-volume group; n = 83) or 6 ml·kg·h of balanced Ringer's solution throughout surgery (control group; n = 83). Primary outcome was the in-hospital complication rate. Secondary outcomes were hospitalization time, and 90-day mortality. RESULTS In-hospital complications occurred in 43 of 83 patients (52%) in the low-volume group and in 61 of 83 (73%) in the control group (relative risk, 0.70; 95% CI, 0.55-0.88; P = 0.006). The rates of gastrointestinal and cardiac complications were lower in the low-volume group than in the control group (5 [6%] vs. 31 [37%]; relative risk, 0.16; 95% CI, 0.07-0.39; P < 0.0001 and 17 [20%] vs. 39 [48%], relative risk, 0.43; 95% CI, 0.26-0.60; P = 0.0003, respectively). The median hospitalization time was 15 days [range, 11, 27d] in the low-volume group and 17 days [11, 95d] in the control group (P = 0.02). The 90-day mortality was 0% in the low-volume group and 4.8% in the control group (P = 0.12). CONCLUSION A restrictive-deferred hydration combined with preemptive norepinephrine infusion during radical cystectomy and urinary diversion significantly reduced the postoperative complication rate and hospitalization time.

Intraoperative Continuous Norepinephrine Infusion Combined with Restrictive Deferred Hydration Significantly Reduces the Need for Blood Transfusion in Patients Undergoing Open Radical Cystectomy: Results of a Prospective Randomised Trial

BACKGROUND Open radical cystectomy (ORC) is associated with substantial blood loss and a high incidence of perioperative blood transfusions. Strategies to reduce blood loss and blood transfusion are warranted. OBJECTIVE To determine whether continuous norepinephrine administration combined with intraoperative restrictive hydration with Ringer's maleate solution can reduce blood loss and the need for blood transfusion. DESIGN, SETTING, AND PARTICIPANTS This was a double-blind, randomised, parallel-group, single-centre trial including 166 consecutive patients undergoing ORC with urinary diversion (UD). Exclusion criteria were severe hepatic or renal dysfunction, congestive heart failure, and contraindications to epidural analgesia. INTERVENTION Patients were randomly allocated to continuous norepinephrine administration starting with 2 μg/kg per hour combined with 1 ml/kg per hour until the bladder was removed, then to 3 ml/kg per hour of Ringer's maleate solution (norepinephrine/low-volume group) or 6 ml/kg per hour of Ringer's maleate solution throughout surgery (control group). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Intraoperative blood loss and the percentage of patients requiring blood transfusions perioperatively were assessed. Data were analysed using nonparametric statistical models. RESULTS AND LIMITATIONS Total median blood loss was 800 ml (range: 300-1700) in the norepinephrine/low-volume group versus 1200 ml (range: 400-2800) in the control group (p<0.0001). In the norepinephrine/low-volume group, 27 of 83 patients (33%) required an average of 1.8 U (±0.8) of packed red blood cells (PRBCs). In the control group, 50 of 83 patients (60%) required an average of 2.9 U (±2.1) of PRBCs during hospitalisation (relative risk: 0.54; 95% confidence interval [CI], 0.38-0.77; p=0.0006). The absolute reduction in transfusion rate throughout hospitalisation was 28% (95% CI, 12-45). In this study, surgery was performed by three high-volume surgeons using a standardised technique, so whether these significant results are reproducible in other centres needs to be shown. CONCLUSIONS Continuous norepinephrine administration combined with restrictive hydration significantly reduces intraoperative blood loss, the rate of blood transfusions, and the number of PRBC units required per patient undergoing ORC with UD.

Critical Analysis of Bladder Sparing with Trimodal Therapy in Muscle-invasive Bladder Cancer: A Systematic Review.

CONTEXT Aims of bladder preservation in muscle-invasive bladder cancer (MIBC) are to offer a quality-of-life advantage and avoid potential morbidity or mortality of radical cystectomy (RC) without compromising oncologic outcomes. Because of the lack of a completed randomised controlled trial, oncologic equivalence of bladder preservation modality treatments compared with RC remains unknown. OBJECTIVE This systematic review sought to assess the modern bladder-preservation treatment modalities, focusing on trimodal therapy (TMT) in MIBC. EVIDENCE ACQUISITION A systematic literature search in the PubMed and Cochrane databases was performed from 1980 to July 2013. EVIDENCE SYNTHESIS Optimal bladder-preservation treatment includes a safe transurethral resection of the bladder tumour as complete as possible followed by radiation therapy (RT) with concurrent radiosensitising chemotherapy. A standard radiation schedule includes external-beam RT to the bladder and limited pelvic lymph nodes to an initial dose of 40Gy, with a boost to the whole bladder to 54Gy and a further tumour boost to a total dose of 64-65Gy. Radiosensitising chemotherapy with phase 3 trial evidence in support exists for cisplatin and mitomycin C plus 5-fluorouracil. A cystoscopic assessment with systematic rebiopsy should be performed at TMT completion or early after TMT induction. Thus, nonresponders are identified early to promptly offer salvage RC. The 5-yr cancer-specific survival and overall survival rates range from 50% to 82% and from 36% to 74%, respectively, with salvage cystectomy rates of 25-30%. There are no definitive data to support the benefit of using of neoadjuvant or adjuvant chemotherapy. Critical to good outcomes is proper patient selection. The best cancers eligible for bladder preservation are those with low-volume T2 disease without hydronephrosis or extensive carcinoma in situ. CONCLUSIONS A growing body of accumulated data suggests that bladder preservation with TMT leads to acceptable outcomes and therefore may be considered a reasonable treatment option in well-selected patients. PATIENT SUMMARY Treatment based on a combination of resection, chemotherapy, and radiotherapy as bladder-sparing strategies may be considered as a reasonable treatment option in properly selected patients.

The impact of pelvic venous pressure on blood loss during open radical cystectomy and urinary diversion: Results from a secondary analysis of a randomized clinical trial

PURPOSE Blood loss and blood substitution are associated with higher morbidity after major abdominal surgery. During major liver resection, low local venous pressure, has been shown to reduce blood loss. Ambiguity persists concerning the impact of local venous pressure on blood loss during open radical cystectomy. We aimed to determine the association between intraoperative blood loss and pelvic venous pressure (PVP) and determine factors affecting PVP. MATERIAL AND METHODS In the frame of a single-center, double-blind, randomized trial, PVP was measured in 82 patients from a norepinephrine/low-volume group and in 81 from a control group with liberal hydration. For this secondary analysis, patients from each arm were stratified into subgroups with PVP <5 mmHg or ≥5 mmHg measured after cystectomy (optimal cut-off value for discrimination of patients with relevant blood loss according to the Youden's index). RESULTS Median blood loss was 800 ml [range: 300-1600] in 55/163 patients (34%) with PVP <5 mmHg and 1200 ml [400-3000] in 108/163 patients (66%) with PVP ≥5 mmHg; (P<0.0001). A PVP <5 mmHg was measured in 42/82 patients (51%) in the norepinephrine/low-volume group and 13/81 (16%) in the control group (P<0.0001). PVP dropped significantly after removal of abdominal packing and abdominal lifting in both groups at all time points (at begin and end of pelvic lymph node dissection, end of cystectomy) (P<0.0001). No correlation between PVP and central venous pressure could be detected. CONCLUSIONS Blood loss was significantly reduced in patients with low PVP. Factors affecting PVP were fluid management and abdominal packing.