Monitoring of peri-operative fluid administration by individualized goal-directed therapy

Enhanced perioperative care in emergency general surgery: the WSES position paper

Enhanced perioperative care protocols become the standard of care in elective surgery with a significant improvement in patients' outcome. The key element of the enhanced perioperative care protocol is the multimodal and interdisciplinary approach targeted to the patient, focused on a holistic approach to reduce surgical stress and improve perioperative recovery. Enhanced perioperative care in emergency general surgery is still a debated topic with little evidence available. The present position paper illustrates the existing evidence about perioperative care in emergency surgery patients with a focus on each perioperative intervention in the preoperative, intraoperative and postoperative phase. For each item was proposed and approved a statement by the WSES collaborative group.

Perioperative Fluid Management

The medical complexity of the geriatric patients has been steadily rising. Still, as outcomes of surgical procedures in the elderly are improving, centers are pushing boundaries. There is also a growing appreciation of the importance of perioperative fluid management on postoperative outcomes, especially in the elderly. Optimal fluid management in this cohort is challenging due to the combination of age-related physiological changes in organ function, increased comorbid burden, and larger fluid shifts during more complex surgical procedures. The current state-of-the-art approach to fluid management in the perioperative period is outlined.

Mid‐regional plasma pro‐atrial natriuretic peptide and stroke volume responsiveness for detecting deviations in central blood volume following major abdominal surgery

Background

A reduced central blood volume is reflected by a decrease in mid‐regional plasma pro‐atrial natriuretic peptide (MR‐proANP), a stable precursor of ANP, and a volume deficit may also be assessed by the stroke volume (SV) response to head‐down tilt (HDT). We determined plasma MR‐proANP during major abdominal procedures and evaluated whether the patients were volume responsive by the end of the surgery, taking the fluid balance and the crystalloid/colloid ratio into account.

Methods

Patients undergoing pancreatic (n = 25), liver (n = 25), or gastroesophageal (n = 38) surgery were included prospectively. Plasma MR‐proANP was determined before and after surgery, and the fluid response was assessed by the SV response to 10^° HDT after the procedure. The fluid strategy was based mainly on lactated Ringer's solution for gastroesophageal procedures, while for pancreas and liver surgery, more human albumin 5% was administered.

Results

Plasma MR‐proANP decreased for patients undergoing gastroesophageal surgery (−9% [95% CI −3.2 to −15.3], p = .004) and 10 patients were fluid responsive by the end of surgery (∆SV > 10% during HDT) with an administered crystalloid/colloid ratio of 3.3 (fluid balance +1389 ± 452 ml). Furthermore, plasma MR‐proANP and fluid balance were correlated (r = .352 [95% CI 0.031–0.674], p < .001). In contrast, plasma MR‐proANP did not change significantly during pancreatic and liver surgery during which the crystalloid/colloid ratio was 1.0 (fluid balance +385 ± 478 ml) and 1.9 (fluid balance +513 ± 381 ml), respectively. For these patients, there was no correlation between plasma MR‐proANP and fluid balance, and no patient was fluid responsive.

Conclusion

Plasma MR‐proANP was reduced in fluid responsive patients by the end of surgery for the patients for whom the fluid strategy was based on more lactated Ringer's solution than human albumin 5%.

Goal-Directed Fluid Therapy Enhances Gastrointestinal Recovery after Laparoscopic Surgery: A Systematic Review and Meta-Analysis

(1) Background: Whether goal-directed fluid therapy (GDFT) provides any outcome benefit as compared to non-goal-directed fluid therapy (N-GDFT) in elective abdominal laparoscopic surgery has not been determined yet. (2) Methods: A systematic literature search was conducted in MEDLINE, Embase, CENTRAL, Web of Science, and Scopus. The main outcomes were length of hospital stay (LOHS), time to first flatus and stool, intraoperative fluid and vasopressor requirements, serum lactate levels, and urinary output. Pooled risks ratios (RRs) with 95% confidence intervals (CI) were calculated for dichotomous outcomes and weighted mean difference (WMD) with 95% CI for continuous outcomes. (3) Results: Eleven studies were included in the quantitative, and fifteen in the qualitative synthesis. LOHS (WMD: -1.18 days, 95% CI: -1.84 to -0.53) and time to first stool (WMD: -9.8 h; CI -12.7 to -7.0) were significantly shorter in the GDFT group. GDFT resulted in significantly less intraoperative fluid administration (WMD: -441 mL, 95% CI: -790 to -92) and lower lactate levels at the end of the operation: WMD: -0.25 mmol L-1; 95% CI: -0.36 to -0.14. (4) Conclusions: GDFT resulted in enhanced recovery of the gastrointestinal function and shorter LOHS as compared to N-GDFT.

Perioperative echocardiography-guided hemodynamic therapy in high-risk patients: a practical expert approach of hemodynamically focused echocardiography

The number of high-risk patients undergoing surgery is growing. To maintain adequate hemodynamic functioning as well as oxygen delivery to the vital organs (DO2) amongst this patient population, a rapid assessment of cardiac functioning is essential for the anesthesiologist. Pinpointing any underlying cardiovascular pathophysiology can be decisive to guide interventions in the intraoperative setting. Various techniques are available to monitor the hemodynamic status of the patient, however due to intrinsic limitations, many of these methods may not be able to directly identify the underlying cause of cardiovascular impairment. Hemodynamic focused echocardiography, as a rapid diagnostic method, offers an excellent opportunity to examine signs of filling impairment, cardiac preload, myocardial contractility and the function of the heart valves. We thus propose a 6-step-echocardiographic approach to assess high-risk patients in order to improve and maintain perioperative DO2. The summary of all echocardiographic based findings allows a differentiated assessment of the patient's cardiovascular function and can thus help guide a (patho)physiological-orientated and individualized hemodynamic therapy.

[Perioperative optimization using hemodynamically focused echocardiography in high-risk patients-A practice guide]

BACKGROUND

The number of high-risk patients undergoing surgery is steadily increasing. In order to maintain and, if necessary, optimize perioperative hemodynamics as well as the oxygen supply to the organs (DO₂) in this patient population, a timely assessment of cardiac function and the underlying pathophysiological causes of hemodynamic instability is essential for the anesthesiologist. A variety of hemodynamic monitoring procedures are available for this purpose; however, due to method-immanent limitations they are often not able to directly identify the underlying cause of cardiovascular impairment.

OBJECTIVE

To present a stepwise algorithm for a perioperative echocardiography-based hemodynamic optimization in noncardiac surgery high-risk patients. In this context, echocardiography on demand according to international guidelines can be performed under certain conditions (hemodynamic instability, nonresponse to hemodynamic treatment) as well as in the context of a planned intraoperative procedure, mostly as a transesophageal echocardiography.

METHODS AND RESULTS

Hemodynamically focused echocardiography as a rapidly available bedside method, enables the timely diagnosis and assessment of cardiac filling obstructions, volume status and volume response, right and left heart function, and the function of the heart valves.

CONCLUSION

Integrating all echocardiographic findings in a differentiated assessment of the patient's cardiovascular function enables a (patho)physiologically oriented and individualized hemodynamic treatment.

Minimally Invasive Hemodynamic Assessment during Obstetric Hysterectomy for Invasive Placentation with Epidural Anesthesia

Background

The present study aimed to describe the evolution of hemodynamic parameters over time of patients with invasive placentation during their third trimester who were delivered via cesarean section and subsequently underwent obstetric hysterectomy under epidural anesthesia.

Methods

A prospective, descriptive, longitudinal, 11-month cohort study of 43 patients aged between 18 and 37 years who presented with invasive placentation. Minimal invasive monitoring was placed before the administration of epidural anesthesia for hemodynamic parameter tracking during the cesarean section. After delivery, the patients underwent an obstetric hysterectomy. Blood loss, hemodynamic parameters, and coagulation were managed via goal-directed therapy. Parameters were compared via repeated measures ANOVA and effect size estimation (Cohen's d).

Results

The mean age of the patients was 29.2 ± 3.4 years and was moderately overweight. They had minor cardiac index variance (P=NS, no significance), vascular systemic resistance index (NS), heart rate (P=NS), and median arterial pressure (P=NS). Differences were observed in the stroke volume index (P=0.015) due to moderately higher values (d = 0.3, P=0.016) in the middle of the surgery. Patients had lower cardiac index (d = -0.36, NS) and cardiac workload requirements (d = -0.29, P=0.034) toward the completion of surgery.

Conclusion

Patients who are in their third trimester and who subsequently underwent obstetric hysterectomy under epidural anesthesia had modest surgical hemodynamic variance and reduced cardiac workload requirements toward the end of the surgery.

The cardiac output optimisation following liver transplant (COLT) trial: a feasibility randomised controlled trial

BACKGROUND

Perioperative goal directed fluid therapy (GDFT) has been shown to reduce postoperative complications following major surgery; this intervention has not been formally evaluated in the setting of liver transplantation.

METHODS

We conducted a prospective trial of GDFT following liver transplantation randomising patients with liver cirrhosis to either 12 h of GDFT using non-invasive cardiac output monitoring or standard care (SC). The primary outcome was feasibility. Secondary outcomes included survival, postoperative complications (Clavien-Dindo), quality of life (by EQ-5D-5L) and resource use. Trial specific follow up occurred at 90 and 180 days after surgery.

RESULTS

The study was feasible. Of 224 eligible patients, 122 were approached, 114 consented to participate and 60 were enrolled into the trial. The mean (SD) volume of IV crystalloid administered to the GDFT group during the 12-h study period was 3968 (2073) ml for the GDFT group and 2510 (1026) ml for the SC group. As regards secondary outcomes there was no difference in survival or overall complication rates. There was no significant difference in quality of life scores and resource use between the groups.

CONCLUSION

A randomised study of GDFT following liver transplantation is feasible. A post-trial stakeholder meeting supported proceeding with a full multi-centre trial.

Perioperative Fluid Administration in Pancreatic Surgery: a Comparison of Three Regimens

BACKGROUND

Optimization of perioperative fluid management is a controversial issue. Weight-adjusted, fixed fluid strategies do not take into account patient hemodynamic status, so that individualized strategies guided by relevant variables may be preferable. We studied this issue in patients undergoing pancreatic surgery within our institution.

METHODS

All patients who underwent a laparotomy for pancreatic cancer during a 5-month period at our hospital (AOUI of Verona, Italy) were eligible to be included in this prospective, observational study. According to the responsible anesthesiologist's free choice, patients received, during surgery, either liberal (12 ml/kg/h) or restricted (4 ml/kg/h) fixed-volume weight-guided replacement fluids or goal-directed (GD) fluid replacement using stroke volume variation (SVV) determined by the FloTrac Vigileo device.

RESULTS

Eighty-six patients were included: 29 in the liberal group, 23 in the restricted group, and 34 in the GD group. The mean duration of surgery was 6 [4-7] h. Patients in the liberal group received more perioperative fluid than those in the GD and restricted groups. Nearly one third of all patients had a major complication, including delayed enteral feeding, and presented a longer duration of hospital stay. Despite the biases related to our limited cohort, there were significantly fewer postoperative complications (such as postoperative fistula, abdominal collection, and hemorrhage) in the restricted and GD groups of patients than in the liberal one.

CONCLUSION

In patients undergoing pancreatic surgery, a restricted or individually guided GD strategy for management of perioperative fluids can result in fewer complications than a liberal fluid strategy. Larger and randomized investigations are warranted to confirm these data on this domain.

Intraoperative Goal-Directed Anesthetic Management of the Patient with Severe Pulmonary Hypertension

Patient: Female, 76

Final Diagnosis: Right upper lung tumor with severe pulmonary hypertension

Symptoms: Shortness of breath

Medication: —

Clinical Procedure: Ecective bronxhoscopy • robotic right upper lobectomy • thoracic lymphadenectomy

Specialty: Anesthesiology

The validity of central venous to arterial carbon dioxide difference to predict adequate fluid management during living donor liver transplantation. A prospective observational study

BACKGROUND

To assess the validity of central and pulmonary veno-arterial CO₂ gradients to predict fluid responsiveness and to guide fluid management during liver transplantation.

METHODS

In adult recipients (ASA III to IV) scheduled for liver transplantation, intraoperative fluid management was guided by pulse pressure variations (PPV). PPV of ≥15% (Fluid Responding Status-FRS) indicated fluid resuscitation with 250 ml albumin 5% boluses repeated as required to restore PPV to < 15% (Fluid non-Responding Status-FnRS). Simultaneous blood samples from central venous and pulmonary artery catheters (PAC) were sent to calculate central venous to arterial CO₂ gap [C(v-a) CO2 gap] and pulmonary venous to arterial CO₂ gap [Pulm(p-a) CO2 gap]. CO and lactate were also measured.

RESULTS

Sixty seven data points were recorded (20 FRS and 47 FnRS). The discriminative ability of central and pulmonary CO₂ gaps between the two states (FRS and FnRS) was poor with AUC of ROC of 0.698 and 0.570 respectively. Central CO₂ gap was significantly higher in FRS than FnRS (P = 0.016), with no difference in the pulmonary CO₂ gap between both states. The central and Pulmonary CO₂ gaps are weakly correlated to PPV [r = 0.291, (P = 0.017) and r = 0.367, (P = 0.002) respectively]. There was no correlation between both CO₂ gaps and both CO and lactate.

CONCLUSION

Central and the Pulmonary CO₂ gaps cannot be used as valid tools to predict fluid responsiveness or to guide fluid management during liver transplantation. CO₂ gaps also do not correlate well with the changes in PPV or CO.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT03123172 . Registered on 31-march-2017.

Reliability of pleth variability index in predicting preload responsiveness of mechanically ventilated patients under various conditions: a systematic review and meta-analysis

Background

Goal-directed volume expansion is increasingly used for fluid management in mechanically ventilated patients. The Pleth Variability Index (PVI) has been shown to reliably predict preload responsiveness; however, a lot of research on PVI has been published recently, and update of the meta-analysis needs to be completed.

Methods

We searched PUBMED, EMBASE, Cochrane Library, Web of Science (updated to November 7, 2018) and the associated references. Relevant authors and researchers had been contacted for complete data.

Results

Twenty-five studies with 975 mechanically ventilated patients were included in this meta-analysis. The area under the curve (AUC) of receiver operating characteristics (ROC) to predict preload responsiveness was 0.82 (95% confidence interval (CI) 0.79–0.85). The pooled sensitivity was 0.77 (95% CI 0.67–0.85) and the pooled specificity was 0.77 (95% CI 0.71–0.82). The results of subgroup of patients without undergoing surgery (AUC =0.86, Youden index =0.65) and the results of subgroup of patients in ICU (AUC =0.89, Youden index =0.67) were reliable.

Conclusion

The reliability of the PVI is limited, but the PVI can play an important role in bedside monitoring for mechanically ventilated patients who are not undergoing surgery. Patients who are expanded with colloid may be more suitable for PVI.

Electronic supplementary material

The online version of this article (10.1186/s12871-019-0744-4) contains supplementary material, which is available to authorized users.

Prospective, randomized clinical trial comparing use of intraoperative transesophageal echocardiography to standard care during radical cystectomy

Purpose:

Our prospective, randomized clinical study aims to evaluate the utility of intraoperative transesophageal echocardiography (TEE) in patients undergoing radical cystectomy.

Materials and Methods:

Eighty patients were randomized to a standard of care group or the intervention group that received continuous intraoperative TEE. Data are presented as means ± standard deviations, median (25^th percentile, 75^th percentile), or numbers and percentages. Characteristics were compared between groups using independent sample t-tests, Wilcoxon–Mann–Whitney tests or Chi-square tests, as appropriate. All tests were two-sided and P < 0.05 was considered to indicate statistical significance.

Results:

Both groups had similar preoperative demographic characteristics. There was a significant difference between central line insertion with all insertions in the control group (15%, 6 vs. 0%, 0; P < 0.003). Of all the perioperative complications, 80% occurred in the control group versus 20% in the TEE group, with 21% of controls experiencing a cardiac or pulmonary complication compared to 5% in the TEE group (8 vs. 2, P < 0.04). The control group patients were more likely to have adverse cardiac complications than the TEE group (15%, 6 vs. 3%, 1; P < 0.040). Postoperative cardiac arrhythmia was observed only in the control group (13%, 5 vs. 0%, 0; P <.007). Prolonged intubation was only observed in the control group (10%, 4 vs. 0%, 0; P < 0.017).

Conclusion:

TEE can be a useful monitoring tool in patients undergoing radical cystectomy, limiting the use of central line insertion and potentially translating into earlier extubation and decreased postoperative cardiac morbidities.

Application of standardized hemodynamic protocols within enhanced recovery after surgery programs to improve outcomes associated with anastomotic leak and conduit necrosis in patients undergoing esophagectomy

Esophagectomy for cancer is associated with high risk for postoperative morbidity. The most serious regularly encountered complication is anastomotic leak and the most feared individual complication is conduit necrosis. Both of these complications affect the length of stay, mortality, quality of life, and survival for patients undergoing esophageal resection. The maintenance of conduit viability is of primary importance in the perioperative care of patients following esophageal resection. It has been shown that restrictive fluid management may be associated with improved postoperative outcomes in abdominal and other types of surgery, but many factors can affect the incidence of anastomotic leak and the viability of the gastric conduit. We have performed a comprehensive review with the aim to give an overview of the available evidence for the use of standardized hemodynamic protocols (SHPs) for esophagectomy and review the hemodynamic protocol, which has been applied within a standardized clinical pathway (SCP) at the Department of Thoracic surgery at the Virginia Mason Medical Center between 2004-2018 where the anastomotic leak rate over the period has been 5.2% and the incidence of conduit necrosis requiring surgical management is zero. The literature review demonstrates that there are few high quality studies that provide scientific evidence for the use of a SHP. The evidence indicates that the use of goal-directed hemodynamic monitoring might be associated with a reduced risk for postoperative complications, shortened length of stay, and decreased need for intensive care unit stay. We propose that the routine application of a SHP can provide a uniform infrastructure to optimize conduit perfusion and decrease the incidence of anastomotic leak.

Nurses' Indications for Administration of Perioperative Intravenous Fluid Therapy-A Prospective, Descriptive, Single-Center Cohort Study

PURPOSE

To examine whether nurse anesthetists and postanesthesia nurses' administration of intravenous (IV) fluid therapy during surgery and in the postanesthesia care unit is based on evidence. Secondarily to investigate if providing indications for IV fluid administration changed nursing practice.

DESIGN

Prospective, descriptive, single-center study in Scandinavia comparing two cohorts.

METHODS

Descriptive, fluid volume, and type data were obtained in both cohorts. Cohort 1 (n = 126) was used as baseline data. In cohort 2 (n = 130), nurses recorded indications for type and volume of fluid therapy using a validated list. Analysis compared median volumes of crystalloid or colloid fluids of surgical types by cohort. Analysis compared frequency of given indication reasons for each IV fluid by surgical type.

FINDINGS

Basic static variables were chosen most frequently for indications of IV fluid needed for all surgeries except high-risk abdominal surgery where dynamic variables were more frequent. Signs and symptoms of inadequate tissue perfusion were only sparsely indicated. The volume of intraoperative crystalloid fluids was statistically different for patients with hip fracture surgery in cohort 2. Volumes of both colloid and crystalloid fluids were significantly higher for high-risk abdominal surgery in cohort 2.

CONCLUSIONS

Nurse anesthetists and nurses in the postanesthesia care unit rely more on basic static parameters than signs of inadequate tissue perfusion when they make decisions about fluid administration. The indications cited for fluid administered to high-risk abdominal surgery and hip fracture patients did not always fit guidelines. This indicates the need of a stronger intervention to change practice to follow evidence-based clinical guidelines.

Effect of restrictive fluid therapy with hydroxyethyl starch during esophagectomy on postoperative outcomes: a retrospective cohort study

BACKGROUND

To improve prognosis after esophageal surgery, intraoperative fluid optimization is important. Herein, we hypothesized that hydroxyethyl starch administration during esophagectomy reduce the total amount of fluid infused and it could have a positive effect on postoperative complication occurrence and mortality.

METHODS

All consecutive adult patients who underwent elective esophageal surgery for cancer were studied. The primary outcome was the development of composite complications including death, cardio-cerebrovascular complications, respiratory complications, renal complications, gastrointestinal complications, sepsis, empyema or abscess, and multi-organ failure. The relationship between perioperative variables and composite complication was evaluated using multivariable logistic regression.

RESULTS

Of 892 patients analyzed, composite complications developed in 271 (30.4%). The higher hydroxyethyl starch ratio in total fluid had a negative relationship with the total fluid infusion amount (r = - 0.256, P <  0.001). In multivariable analysis, intraoperatively administered total fluid per weight per hour (odds ratio, 1.248; 95% CI, 1.153-1.351; P <  0.001) and HES-to-crystalloid ratio (odds ratio, 2.125; 95% CI, 1.521-2.969; P <  0.001) were associated with increased risks of postoperative composite outcomes.

CONCLUSIONS

Although hydroxyethyl starch administration reduces the total fluid infusion amount during esophageal surgery for cancer, intravenous hydroxyethyl starch infusion is associated with an increasing risk of postoperative composite complications.

Efficacy of Stroke Volume Variation, Cardiac Output and Cardiac Index as Predictors of Fluid Responsiveness using Minimally Invasive Vigileo Device in Intracranial Surgeries

Introduction:

Functional hemodynamic monitoring using dynamic parameters such as stroke volume variations (SVVs) based on pulse contour analysis is considered more accurate than central venous pressure and mean arterial pressure (MAP) in predicting fluid responsiveness. New device, i.e., Vigileo system, allows automatic and continuous monitoring of cardiac output (CO) based on pulse contour analysis and respiratory stroke volume.

Aim:

The study aims to test the above hypothesis using graded volume loading step (VLS) to assess the accuracy of SVV as a predictor of fluid responsiveness in patients undergoing intracranial surgery.

Materials and Methods:

After taking ethical committee approval and informed consent, 60 patients aged between 18 and 55 years belonging to the American Society of Anesthesiologists physical status Class I and II, of either sex, scheduled for brain surgery were included in the study. In this study, 5 min after intubation, with stable hemodynamics, patients received volume loading in successive steps (VLS) of 200 ml of lactated Ringer's solution until the stroke volume increased to <10%. Blood pressure (BP), heart rate (HR), stroke volume (SV), and SVV were measured before and after each VLS. Optimal preload augmentation required by each patient was measured by the number of VLS after which an increase in SV was <10%.

Results:

There was a significant decrease in the baseline BP and SV in responsive and nonresponsive groups for the first VLS, but there is no change in HR statistically. There was a significant change in SV after first VLS. Receiver operating characteristic analysis showed a larger area under the curve of 0.758 for SVV compared to other measured variables. The median number of VLS administered were 2 per patient equating to a mean ± SD requirement of 368 ± 176 ml of crystalloid per patient as the optimal preoperative infusion volume.

Conclusion:

SVV is a better predictor of preload responsiveness measured with third-generation Vigileo device when compared to BP and HR.

[Evolution of enhanced recovery after surgery: from the beginning of the study of stress to the introduction in emergency surgery]

Effectiveness of enhanced recovery program is being earnestly confirmed in various surgical areas. Certain aspects of fast track rehabilitation are analyzed in the article.

The Use of Point-of-Care Ultrasonography in Trauma Anesthesia

Caring for the trauma patient requires an in-depth knowledge of the pathophysiology of trauma, the ability to rapidly diagnose and intervene to reverse the derangements caused by shock states, and an aptitude for the use of advanced monitoring techniques and perioperative point-of-care ultrasonography (P-POCUS) to assist in diagnosis and delivery of care. Historically, anesthesiology has lagged behind in wholly embracing this technology. P-POCUS has the potential to allow the trauma anesthesiologist to diagnose numerous injuries, quickly guide the placement of central vascular catheters and invasive monitors, and assess the efficacy of interventions.

Impact of postoperative intravenous fluid administration on complications following elective hepato-pancreato-biliary surgery

BACKGROUND

The impact of perioperative intravenous fluid administration on surgical outcomes has been documented in literature, but not specifically studied in the context of hepato-pancreato-biliary (HPB) surgery. This study aimed to investigate the impact of postoperative intravenous fluid administration on intensive care unit (ICU), in this subgroup of patients.

METHODS

A single-center retrospective cohort of 241 HPB patients was assessed, focusing on intravenous fluid administration in ICU, during the first 24 h. Intravenous fluid variables were compared to hospital stay and postoperative complications. Data were assessed using Spearman's correlation test for bivariate correlations and logistic regression for multivariate analysis.

RESULTS

The median volume of intravenous fluid administered in the first 24 h postoperatively was 4380 mL, of which 2200 mL was crystalloid, 1500 mL colloid and 680 mL "other" fluid. Patients with one or more complications had a higher median total intravenous fluid input (4790 vs. 4300 mL), higher colloid volume (2000 vs. 1500 mL), lower urine output (1595 vs. 1900 mL) and greater overall fluid balance (+3040 vs.+2553 mL) than those without complications. There were correlations between total intravenous fluid volume administered (r = 0.278, P < 0.001), intravenous colloid input (r = 0.278, P < 0.001), urine output (r = -0.295, P < 0.001), positive fluid balance (r = 0.344, P < 0.001) and length of hospital stay. Logistic regression model was constructed to predict the occurrence of one or more complications; total intravenous fluid volume and overall fluid balance were both independent significant predictors (OR = 2.463, P = 0.007; OR = 1.001, P = 0.011; respectively).

CONCLUSIONS

Administration of high volumes of intravenous fluids in the first 24 hours post-HPB surgery, along with higher positive fluid balance is associated with a higher rate of complications and longer hospital stay. Moreover, lower urine output is associated with longer hospital stay. Whether these are the cause of complications or the result of them remains unclear.

Pre-operative fluid bolus for improved haemodynamic stability during minor surgery: A prospectively randomized clinical trial

BACKGROUND

Haemodynamic instability during the induction of anaesthesia and surgery is common and may be related to hypovolaemia caused by pre-operative fasting or chronic diuretic therapy. The aim of our prospective, controlled, randomized study was to test the hypothesis that a predefined fluid bolus given prior to general anaesthesia for minor surgery would increase haemodynamic stability during anaesthetic induction.

METHODS

Two hundred and nineteen fairly healthy adult patients requiring minor surgery were enrolled. All received standard treatment, including a pulse contour analysing device for non-invasive measurement of cardiac index. Infusion therapy was started in all patients at induction. The intervention group (106 patients) was randomized to receive an additional fluid bolus of 8 mL/kg Ringer's acetate solution before the induction of anaesthesia. The primary endpoint was the incidence of haemodynamic instability, defined as a significant reduction of blood pressure or cardiac index during induction of anaesthesia.

RESULTS

The interventional group had a lesser incidence of haemodynamic instability during induction (41.5% vs 56.6%, P = .025). This group also had higher cardiac index, stroke volume index, systolic and mean blood pressure and a greater left ventricular end-diastolic area.

CONCLUSIONS

A fluid bolus prior to anaesthesia reduced the incidence of haemodynamic instability during induction of general anaesthesia. The total fluid volume was slightly greater in the intervention group compared to the control group (1370 ± 439 mL vs 1219 ± 483 mL, P = .007). We conclude that a defined fluid bolus can help stabilizing haemodynamics in patients undergoing general anaesthesia.

Effects of perioperative goal-directed fluid therapy combined with the application of alpha-1 adrenergic agonists on postoperative outcomes: a systematic review and meta-analysis

Background

Past studies have demonstrated that goal-directed fluid therapy (GDFT) may be more marginal than previously believed. However, beneficial effects of alpha-1 adrenergic agonists combined with appropriate fluid administration is getting more and more attention. This study aimed to systematically review the effects of goal-directed fluid therapy (GDFT) combined with the application of alpha-1 adrenergic agonists on postoperative outcomes following noncardiac surgery.

Methods

This meta-analysis included randomized controlled trials (RCTs) on GDFT combined with the application of alpha-1 adrenergic agonists in patients undergoing noncardiac surgery. The primary outcomes included the postoperative mortality rate and length of hospital stay (LOS). The secondary outcome indexes were the incidence of postoperative complications and recovery of postoperative gastrointestinal (GI) function. The traditional pairwise meta-analysis was conducted to compare the effect of fluid therapy. The quality of included RCTs was evaluated according to the Cochrane Collaboration’s risk-of-bias tool. Also, the publication bias was detected using funnel plots, Egger’s regression test, and Begg’s adjusted rank correlation test. The meta-analysis was conducted using the RevMan 5.3 and Stata 14.0 software.

Results

Thirty-two eligible RCTs were included in this meta-analysis. Perioperative GDFT combined with the application of alpha-1 adrenergic agonists was associated with a significant reduction in LOS (P = 0.002; I² = 69%), and overall complication rates (P = 0.04; I² = 41%). It facilitated gastrointestinal function recovery, as demonstrated by shortening the time to first flatus by 6.30 h (P < 0.00001; I² = 91%) and the time to toleration of solid food by 1.69 days (P < 0.00001; I² = 0%). Additionally, there was no significant reduction in short-term mortality in the GDFT combined with alpha-1 adrenergic agonists group (P = 0.05; I² = 0%).

Conclusion

This systematic review of available evidence suggested that the use of perioperative GDFT combined with alpha-1 adrenergic agonists might facilitate recovery in patients undergoing noncardiac surgery.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0564-y) contains supplementary material, which is available to authorized users.

Perioperative transesophageal echocardiography for non-cardiac surgery

PURPOSE

The use of transesophageal echocardiography (TEE) has evolved to include patients undergoing high-risk non-cardiac procedures and patients with significant cardiac disease undergoing non-cardiac surgery. Implementation of basic TEE education in training programs has increased across a broad spectrum of procedures in the perioperative arena. This paper describes the use of perioperative TEE in non-cardiac surgery and provides an overview of the basic TEE examination.

PRINCIPAL FINDINGS

Perioperative TEE is used to monitor hemodynamic parameters in non-cardiac procedures where there is a high risk of hemodynamic instability. Its use extends to include moderate-risk procedures for patients with significant cardiac diseases such as low ejection fraction, hypertrophic cardiomyopathy, severe valve lesions, or congenital heart disease. Vascular procedures involving the aorta, blunt trauma, and liver transplantation are all examples of procedures that may benefit from TEE. Transesophageal echocardiography examination allows assessment of volume status, ventricular function, diagnosis of gross valvular pathology and pericardial tamponade, as well as close monitoring of cardiac output, response to therapy, and the impact of ongoing surgical manipulation. In patients with unexplained and unexpected hemodynamic instability, "rescue TEE" can be used to help identify the underlying cause.

CONCLUSIONS

Perioperative TEE is emerging as a preferred tool to manage hemodynamics in high-risk procedures and in high-risk patients undergoing non-cardiac surgery. A rescue TEE examination protocol is a helpful approach for early identification of the etiology of hemodynamic instability.

Intraoperative fluid management: Past and future, where is the evidence?

Currently, there is no consensus about the optimum intraoperative fluid therapy strategy. There is growing body of evidence supports the beneficial effects of adopting “Goal-directed therapy” over either the “liberal” or “restrictive” fluid therapy strategies. In this narrative review, we have presented the evidence to support the optimum strategy for intraoperative therapy. In conclusion, whatever the intravenous fluid replacement strategy used, the anesthesiologist must be prepared to adjust the composition and rate of the fluids administered to provide sufficient intravascular fluid volume for adequate perfusion of vital organs without overwhelming the glycocalyx function with fluid overloads.

Low vs. high haemoglobin trigger for transfusion in vascular surgery: protocol for a randomised trial

BACKGROUND

In patients with cardiovascular disease, guidelines for administration of red blood cells (RBC) are mainly based on studies outside the vascular surgical setting with the recommendation to use a haemoglobin (hb) trigger-level lower than by guidelines from The European Society for Vascular Surgery. Restricting RBC transfusion may affect blood O₂ transport with a risk for development of tissue ischaemia and postoperative complications.

METHODS

In a single-centre, open-label, assessor blinded trial, 58 vascular surgical patients (> 40 years of age) awaiting open surgery of the infrarenal aorta or infrainguinal arterial bypass surgery undergo a web-based randomisation to one of two groups: perioperative RBC transfusion triggered by hb < 8 g/dl or hb < 9.7 g/dl. Administration of fluid follows an individualised strategy by optimising cardiac stroke volume and near-infrared spectroscopy determines tissue oxygenation. Serious adverse event rates are: myocardial injury (troponin-I ≥ 45 ng/l or ischaemic electrocardiographic findings at day 30), acute kidney injury, death, stroke and severe transfusion reactions. A follow-up visit takes place 30 days after surgery and a follow-up of serious adverse events in the Danish National Patient Register within 90 days is pending.

DISCUSSION

This trial is expected to determine whether a RBC transfusion triggered by hb < 9.7 g/dl compared with hb < 8 g/dl results in adequate separation of postoperative hb levels, transfusion of more RBC units and maintains a higher tissue oxygenation. The results will inform the design of a multicentre trial for evaluation of important postoperative outcomes.

Effect of perioperative goal-directed hemodynamic therapy on postoperative recovery following major abdominal surgery-a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Goal-directed hemodynamic therapy (GDHT) has been used in the clinical setting for years. However, the evidence for the beneficial effect of GDHT on postoperative recovery remains inconsistent. The aim of this systematic review and meta-analysis was to evaluate the effect of perioperative GDHT in comparison with conventional fluid therapy on postoperative recovery in adults undergoing major abdominal surgery.

METHODS

Randomized controlled trials (RCTs) in which researchers evaluated the effect of perioperative use of GDHT on postoperative recovery in comparison with conventional fluid therapy following abdominal surgery in adults (i.e., >16 years) were considered. The effect sizes with 95% CIs were calculated.

RESULTS

Forty-five eligible RCTs were included. Perioperative GDHT was associated with a significant reduction in short-term mortality (risk ratio [RR] 0.75, 95% CI 0.61-0.91, p = 0.004, I ² = 0), long-term mortality (RR 0.80, 95% CI 0.64-0.99, p = 0.04, I ² = 4%), and overall complication rates (RR 0.76, 95% CI 0.68-0.85, p < 0.0001, I ² = 38%). GDHT also facilitated gastrointestinal function recovery, as demonstrated by shortening the time to first flatus by 0.4 days (95% CI -0.72 to -0.08, p = 0.01, I ² = 74%) and the time to toleration of oral diet by 0.74 days (95% CI -1.44 to -0.03, p < 0.0001, I ² = 92%).

CONCLUSIONS

This systematic review of available evidence suggests that the use of perioperative GDHT may facilitate recovery in patients undergoing major abdominal surgery.

The effect of intraoperative and 6-h postoperative intravenous administration of low-dose prostacyclin on the endothelium, hemostasis, and hemodynamics in patients undergoing a pancreaticoduodenoctemy: a randomized-controlled pilot study

BACKGROUND

Capillary leakage, secondary to endothelial breakdown, is common in patients undergoing major surgical procedures with extensive tissue injury and this is associated with increased morbidity and mortality. Prostacyclin has been ascribed cytoprotective properties together with its vasodilatory and antiplatelet effects. The present pilot study investigated the safety and endothelial protective effects of low-dose prostacyclin infusion.

PATIENTS AND METHODS

A randomized placebo-controlled pilot study evaluating the effect of prostacyclin (iloprost) infusion (1.0 ng/kg/min) versus placebo (saline infusion) intraoperatively and 6 h postoperatively in patients undergoing a pancreaticoduodenoctemy was carried out. Hemodynamics were evaluated by Nexfin, hemostasis was evaluated by thrombelastography, and transfusion requirements were registered. Endothelial damage was evaluated by circulating sE-selectin, soluble thrombomodulin, and nucleosomes.

RESULTS

Comparable baseline demography and surgical time were found. Hemodynamics were comparable between groups. The placebo group received more red blood cells, median 115 ml [interquartile range (IQR): 0-296 ml] versus 0 ml (IQR: 0-0 ml), P=0.027, at the postoperative ward and after 6 h. Thrombelastography maximum clot firmness decreased intraoperatively only in the placebo group (P=0.034)). Soluble thrombomodulin increased more in the placebo group postoperatively [1.63 ng/ml (IQR: 0.65-2.55 ng/ml) versus 0.40 ng/ml (IQR: 0.21-0.63 ng/ml), P=0.027] and 6 h postoperatively [1.83 (1.1-2.36) versus 0.67 (0.42-0.91), P=0.027]. Nucleosomes increased intraoperatively and postoperatively only in the placebo group; thus, the overall level of nucleosomes was higher in the placebo group (P=0.019).

CONCLUSION

Intraoperative and postoperative low-dose prostacyclin infusion is safe and associated with reduced endothelial cell damage in patients undergoing a pancreaticoduodenoctemy compared with those receiving placebo.

A reduced gastric corpus microvascular blood flow during Ivor-Lewis esophagectomy detected by laser speckle contrast imaging technique

BACKGROUND

Reduced microvascular blood flow is related to anastomotic insufficiency following esophagectomy, emphasizing a need for intraoperative monitoring of the microcirculation. This study evaluated if laser speckle contrast imaging (LSCI) was able to detect intraoperative changes in gastric microcirculation.

METHODS

Gastric microcirculation was assessed prior to and after reconstruction of gastric continuity in 25 consecutive patients operated for adenocarcinoma with open Ivor-Lewis esophagectomy while hemodynamic variables were recorded.

RESULTS

During upper laparotomy, microcirculation at the corpus decreased by 25% from baseline to mobilization of the stomach (p = .008) and decreased further (to a total decrease of 40%) following gastric pull to the thorax (p = .013). On the other hand, microcirculation at the antrum did not change significantly after gastric mobilization (p = .091). The decrease in corpus microcirculation took place unrelated to central cardiovascular variables.

CONCLUSION

Using LSCI technique, we identified a reduced microcirculation at the corpus area during open Ivor-Lewis esophagectomy. LSCI provides an option for real-time assessment of gastric microcirculation and could form basis for intraoperative stabilization of the microcirculation.

Plasma pro-atrial natriuretic peptide to estimate fluid balance during open and robot-assisted esophagectomy: a prospective observational study

Background

It remains debated how much fluid should be administered during surgery. The atrial natriuretic peptide precursor proANP is released by atrial distension and deviations in plasma proANP are reported associated with perioperative fluid balance. We hypothesized that plasma proANP would decrease when the central blood volume is compromised during the abdominal part of robot-assisted hybrid (RE) esophagectomy and that a positive fluid balance would be required to maintain plasma proANP.

Methods

Patients undergoing RE (n = 25) or open (OE; n = 25) esophagectomy for gastroesophageal cancer were included consecutively in this prospective observational study. Plasma proANP was determined repetitively during esophagectomy to allow for distinction between the abdominal and thoracic part of the procedure. The RE group was 15° head up tilted during the abdominal procedure.

Results

The blood loss was 250 (150–375) (RE) and 600 ml (390–855) (OE) (p = 0.01), but the two groups of patients were provided with a similar positive fluid balance: 1705 (1390–1983) vs. 1528 ml (1316–1834) (p = 0.4). However, plasma proANP decreased by 21% (p < 0.01) during the abdominal part of RE carried out during moderate head-up tilt, but only by 11% (p = 0.01) during OE where the patients were supine. Plasma proANP and fluid balance were correlated in the RE-group (r = 0.5 (0.073–0.840), p = 0.02) and tended to correlate in the OE group (r = 0.4 (−0.045–0.833), p = 0.08).

Conclusion

The results support that plasma proANP decreases when the central blood volume is compromised and suggest that an about 2200 ml surplus administration of crystalloid is required to maintain plasma proANP during esophagectomy.

Trial registration

Clinicaltrials.gov (NCT02077673). Registered retrospectively February 12^th 2014.

Correlation of the ratio of caudal vena cava diameter and aorta diameter with systolic pressure variation in anesthetized dogs

OBJECTIVE

To evaluate the correlation coefficient of the ratio between diameter of the caudal vena cava (CVC) and diameter of the aorta (Ao) in dogs as determined ultrasonographically with systolic pressure variation (SPV).

ANIMALS

14 client-owned dogs (9 females and 5 males; mean ± SD age, 73 ± 40 months; mean body weight, 22 ± 7 kg) that underwent anesthesia for repair of skin wounds.

PROCEDURES

Anesthesia was induced. Controlled mechanical ventilation with a peak inspiratory pressure of 8 cm H2O was immediately started, and SPV was measured. During a brief period of suspension of ventilation, CVC-to-Ao ratio was measured on a transverse right-lateral intercostal ultrasonographic image obtained at the level of the porta hepatis. When the SPV was ≥ 4 mm Hg, at least 1 bolus (3 to 4 mL/kg) of Hartmann solution was administered IV during a 1-minute period. Bolus administration was stopped and the CVC-to-Ao ratio measured when SPV was < 4 mm Hg. Correlation coefficient analysis was performed.

RESULTS

28 measurements were obtained. The correlation coefficient was 0.86 (95% confidence interval, 0.72 to 0.93). Mean ± SD SPV and CVC-to-Ao ratio before bolus administration were 7 ± 2 mm Hg and 0.52 ± 0.16, respectively. Mean ± SD SPV and CVC-to-Ao ratio after bolus administration were 2 ± 0.6 mm Hg and 0.91 ± 0.13, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

In this study, the CVC-to-Ao ratio was a feasible, noninvasive ultrasonographically determined value that correlated well with SPV.

Intraoperative modifiable risk factors of colorectal anastomotic leakage: Why surgeons and anesthesiologists should act together

BACKGROUND

Colorectal anastomotic leakage (CAL) is a major surgical complication in intestinal surgery. Despite many optimizations in patient care, the incidence of CAL is stable (3-19%) [1]. Previous research mainly focused on determining patient and surgery related risk factors. Intraoperative non-surgery related risk factors for anastomotic healing also contribute to surgical outcome. This review offers an overview of potential modifiable risk factors that may play a role during the operation.

METHODS

Two independent literature searches were performed using EMBASE, Pubmed and Cochrane databases. Both clinical and experimental studies published in English from 1985 to August 2015 were included. The main outcome measure was the risk of anastomotic leakage and other postoperative complications during colorectal surgery. Determined risk factors of CAL were stated as strong evidence (level I and II high quality studies), and potential risk factors as either moderate evidence (experimental studies level III), or weak evidence (level IV or V studies).

RESULTS

The final analysis included 117 articles. Independent factors of CAL are diabetes mellitus, hyperglycemia and a high HbA1c, anemia, blood loss, blood transfusions, prolonged operating time, intraoperative events and contamination and a lack of antibiotics. Unequivocal are data on blood pressure, the use of inotropes/vasopressors, oxygen suppletion, type of analgesia and goal directed fluid therapy. No studies could be found identifying the impact of body core temperature or mean arterial pressure on CAL. Subjective factors such as the surgeons' own assessment of local perfusion and visibility of the operating field have not been the subject of relevant studies for occurrence in patients with CAL.

CONCLUSION

Both surgery related and non-surgery related risk factors that can be modified must be identified to improve colorectal care. Surgeons and anesthesiologists should cooperate on these items in their continuous effort to reduce the number of CAL. A registration study determining individual intraoperative risk factors of CAL is currently performed as a multicenter cohort study in the Netherlands.

How the Nurse Anesthetist Decides to Manage Perioperative Fluid Status

PURPOSE

To determine the factors that affect how nurse anesthetists in a county in Sweden decide how to manage perioperative fluid status.

DESIGN

A cross-sectional qualitative study was conducted at two surgical wards in a county hospital.

METHODS

Sixteen nurse anesthetists were interviewed to explore how nurse anesthetists assess patients' intraoperative fluid requirements and the subsequent measures adopted.

FINDING

Three categories emerged through content analysis: clinical criteria and the thought process that drives decision making, interdependence in decision making, and uncertainty in decision making.

CONCLUSIONS

This study revealed differences with regard to fluid management among nurse anesthetists in a county in Sweden. For the assessments and subsequent measures that are carried out to ensure optimal fluid therapy, more research is needed to provide evidence, and evidence-based guidelines need to be developed in Sweden.

ADRB2 gly16gly Genotype, Cardiac Output, and Cerebral Oxygenation in Patients Undergoing Anesthesia for Abdominal Aortic Aneurysm Surgery

BACKGROUND

Gly16arg polymorphism of the adrenergic β2-receptor is associated with the elevated cardiac output (Q) in healthy gly16-homozygotic subjects. We questioned whether this polymorphism also affects Q and regional cerebral oxygen saturation (SCO2) during anesthesia in vascular surgical patients.

METHODS

One hundred sixty-eight patients (age 71 ± 6 years) admitted for elective surgery were included. Cardiovascular variables were determined before and during anesthesia by intravascular pulse contour analysis (Nexfin) and SCO2 by cerebral oximetry (INVOS 5100C). Genotyping was performed with the TaqMan assay.

RESULTS

Before anesthesia, Q and SCO2 were 4.7 ± 1.2 L/min and 66% ± 8%, respectively, and linearly correlated (r = 0.35, P < .0001). In patients with the gly16gly genotype baseline, Q was approximately 0.4 L/min greater than in arg16 carriers (CI95: 0.0-0.8, Pt test = .03), but during anesthesia, the difference was 0.3 L/min (Pmixed-model = .07). Post hoc analysis revealed the change in SCO2 from baseline to the induction of anesthesia to be on average 2% greater in gly16gly homozygotes than in arg16 patients when adjusted for the change in Q (P = .03; CI95: 0.2-4.0%).

CONCLUSIONS

This study suggests that the β2-adrenoceptor gly16gly genotype is associated with the elevated resting Q. An interesting trend to greater frontal lobe oxygenation at induction of anesthesia in patients with gly16gly genotype was found, but because of insufficient sample size and lack of PCO2 control throughout the measurements, the presented data may only serve as the hypothesis generating for future studies. The confidence limits indicate that the magnitude of the effects may range from clinically insignificant to potentially important.

Context-sensitive fluid therapy in critical illness

Microcirculatory alterations are frequently observed in critically ill patients undergoing major surgery and those who suffer from trauma or sepsis. Despite the need for adequate fluid administration to restore microcirculation, there is no consensus regarding optimal fluid therapy for these patients. The recent recognition of the importance of the endothelial glycocalyx layer in capillary fluid and solute exchange has largely changed our views on fluid therapy in critical illness. Given that disease status largely differs among critically ill patients, fluid therapy must not be considered generally, but rather tailored to the clinical condition of each patient. This review outlines the current understanding of context-sensitive volume expansion by fluid solutions and considers its clinical implications for critically ill patients. The modulation of capillary hydrostatic pressure through the appropriate use of vasopressors may increase the effectiveness of fluid infusion and thereby reduce detrimental effects resulting from excessive fluid administration.

Impact of Albumin on Coagulation Competence and Hemorrhage During Major Surgery: A Randomized Controlled Trial

For patients exposed to a massive blood loss during surgery, maintained coagulation competence is important. It is less obvious whether coagulation competence influences bleeding during elective surgery where patients are exposed to infusion of a crystalloid or a colloid. This randomized controlled trial evaluates whether administration of 5% human albumin (HA) or lactated Ringer solution (LR) affects coagulation competence and in turn blood loss during cystectomy due to bladder cancer. Forty patients undergoing radical cystectomy were included to receive either 5% HA (n = 20) or LR (n = 20). Nineteen patients were analyzed in the HA group and 20 patients in the lactated Ringer group. Blinded determination of the blood loss was similar in the 2 groups of patients: 1658 (800-3300) mL with the use of HA and 1472 (700-4330) mL in the lactated Ringer group (P = 0.45). Yet, by thrombelastography (TEG) evaluated coagulation competence, albumin affected clot growth (TEG-angle 69 ± 5 vs 74° ± 3°, P < 0.01) and strength (TEG-MA: 59 ± 6 vs 67 ± 6 mm, P < 0.001) more than LR. Furthermore, by multivariate linear regression analyses reduced TEG-MA was independently associated with the blood loss (P = 0.042) while administration of albumin was related to the changes in TEG-MA (P = 0.029), aPPT (P < 0.022), and INR (P < 0.033). This randomized controlled trial demonstrates that administration of HA does not affect the blood loss as compared to infusion of LR. Also the use of HA did not affect the need for blood transfusion, the incidence of postoperative complications, or the hospital in-stay. Yet, albumin decreases coagulation competence during major surgery and the blood loss is related to TEG-MA rather than to plasma coagulation variables.

Coagulation competence for predicting perioperative hemorrhage in patients treated with lactated Ringer's vs. Dextran--a randomized controlled trial

BACKGROUND

Perioperative hemorrhage may depend on coagulation competence and this study evaluated the influence of coagulation competence on blood loss during cystectomy due to bladder cancer.

METHODS

Forty patients undergoing radical cystectomy were included in a randomized controlled trial to receive either lactated Ringer's solution or Dextran 70 (Macrodex ®) that affects coagulation competence.

RESULTS

By thrombelastography evaluated coagulation competence, Dextran 70 reduced "maximal amplitude" (MA) by 25 % versus a 1 % reduction with the administration of lactated Ringer's solution (P <0.001). Blinded evaluation of the blood loss was similar in the two groups of patients - 2339 ml with the use of Dextran 70 and 1822 ml in the lactated Ringer's group (P = 0.27). Yet, the blood loss was related to the reduction in MA (r = -0.427, P = 0.008) and by multiple regression analysis independently associated with MA (P = 0.01). Thus, 11 patients in the dextran group (58 %) developed a clinical significant blood loss (>1500 ml) compared to only four patients (22 %) in the lactated Ringer's group (P = 0.04).

CONCLUSIONS

With the use of Dextran 70 vs. lactated Ringer's solution during cystectomy, a relation between hemorrhage and coagulation competence is demonstrated. Significant bleeding develops based on an about 25 % reduction in thrombelastography determined maximal amplitude. A multivariable model including maximal amplitude discriminates patients with severe perioperative bleeding during cystectomy.

TRIAL REGISTRATION

The study was accepted on January 7(th), 2013 at www.clinicaltrialsregister.eu EudraCT 2012-005040-20.

Postoperative volume balance: does stroke volume increase in Trendelenburg's position?

In healthy humans, stroke volume (SV) and cardiac output (CO) do not increase with expansion of the central blood volume by head-down tilt or administration of fluid. Here, we exposed 85 patients to Trendelenburg's position about one hour after surgery while cardiovascular variables were determined non-invasively by Modelflow. In Trendelenburg's position, SV (83 ± 19 versus 89 ± 20 ml) and CO (6·2 ± 1·8 versus 6·8 ± 1·8 l/min; both P<0·05) increased, while heart rate (75 ± 15 versus 76 ± 14 b min^-1 ) and mean arterial pressure were unaffected (84 ± 15 versus 84 ± 16 mmHg). For the 33 patients (39%) with a > 10% increase in SV (from 78 ± 16 to 90 ± 17 ml) corresponding to an increase in CO from 5·9 ± 1·5 to 6·9 ± 1·6 l min^-1 (P<0·05) when tilted head-down, administration of 250 ml Ringer's lactate solution increased SV (to 88 ± 18 ml) and CO (to 6·8 ± 1·7 l min^-1 ). In conclusion, determination of SV and/or CO in Trendelenburg's position can be used to evaluate whether a patient is in need of IV fluid as here exemplified after surgery.