Pleth variability index or stroke volume optimization during open abdominal surgery: a randomized controlled trial

Background

The impact of Goal Directed Fluid Therapy (GDFT) based on the non-invasive Pleth Variability Index (PVI) on clinical outcome after abdominal surgery has only sparingly been explored. The purpose of this study was to compare the effect of intraoperative GDFT guided by PVI to a control group using esophageal Doppler on the incidence of complications and length of hospital stay after major abdominal surgery. We hypothesized that there would be no difference between the groups.

Methods

This was a randomized controlled trial in a Swedish university hospital between November 2011 and January 2015; 150 patients scheduled for open abdominal surgery lasting 2 h or more were included. Exclusion criteria included hepatic resection or severe cardiac arrhythmia. The patients were randomized 1:1 to either the intervention group or the control group. The intervention group received intraoperative GDFT by administering fluid boluses of 3 ml/kg tetrastarch aiming at a PVI value below 10%, while GDFT in the control group aimed for optimization of stroke volume as assessed with esophageal Doppler. Blinded observers assessed complications until postoperative day 30 using pre-defined definitions, as well as length of hospital stay.

Results

One hundred and-fifty patients were randomized and 146 patients were available for the final data analysis. Median duration of surgery was 3 h. A total of 64 complications occurred in the PVI group (N = 74) and 70 in the Doppler group (N = 72) (p = 0.93). Median (IQR) length of stay was 8.0 (8.0) days in the PVI group and 8.0 (9.5) in the Doppler group (P = 0.57).

Conclusions

No difference in clinical outcome, as defined by number of postoperative complications, and length of hospital stay, was found when goal directed fluid therapy was applied using PVI as an alternative to esophageal Doppler. PVI appears to be an acceptable alternative to esophageal Doppler for goal directed fluid therapy during major open abdominal surgery.

Trial registration

Clinicaltrials.gov NCT01458678. Date of first registration October 20, 2011.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0579-4) contains supplementary material, which is available to authorized users.

Goal-directed fluid therapy versus conventional fluid therapy in colorectal surgery: A meta analysis of randomized controlled trials

OBJECTIVES

This meta-analysis was conducted to compare the effects of goal-directed fluid therapy (GDFT) versus conventional fluid therapy (CFT) in colorectal surgery on patients' postoperative outcome and to detect whether the results differ between studies with the Enhanced Recovery After Surgery (ERAS) protocol and those without, between studies using different devices for GDFT, or between different surgical approaches (laparoscopy or laparotomy).

METHODS

The Cochrane Library, PubMed, Embase, Wanfang Data and ClinicalTrials.com were searched for studies from January,1990 to February, 2018. Randomized controlled trials (RCTs) comparing both two abovementioned fluid therapy protocols in colorectal surgery were included. The primary outcome was 30-day mortality after surgery. Secondary outcomes were length of hospital stay (LOS), complication rate, ICU admission and gastrointestinal indicators.

RESULTS

Eleven studies were included, including a total of 1281 patients: the GDFT group included 624 patients and the control group included 657 patients. No significant differences were found between groups in 30-day mortality (relative risk, RR 0.86,0.28 to 2.63, P = 0.79), LOS (weighted mean difference, WMD 0.22,-0.1 to 0.55, P = 0.18), and ICU admission (RR 0.42, 0.17 to 1.04, P = 0.06). However, the GDFT group had a lower complication rate (RR 0.84,0.71 to 0.99, P = 0.04). In subgroup analyses, time to first flatus and time to tolerate an oral diet were shorter in GDFT group than the control group in studies who did not use the ERAS protocol. No publication bias was identified according to Begg's test.

CONCLUSION

Compared with conventional fluid therapy, GDFT may not improve patients' postoperative outcome in colorectal surgery. However, the improvement of gastrointestinal function associated with GDFT over conventional fluid therapy was significant in the surgeries that did not use the ERAS protocol.

Stepped wedge cluster randomised controlled trial to assess the effectiveness of an optimisation strategy for general anaesthesia on postoperative morbidity and mortality in elderly patients (the OPTI-AGED study): a study protocol

INTRODUCTION

Elderly patients constitute an increasingly large proportion of the high-risk surgical group. In adult patients, several specific intraoperative approaches such as cardiac output-guided haemodynamic therapy, depth of anaesthesia monitoring (DAM) or lung-protective ventilation (LPV) are designed to reduce postoperative mortality and surgical complications. However, none of these approaches has been specifically performed in the elderly, and no evaluation of a multimodal optimisation strategy for general anaesthesia has been achieved in this population.

AIMS

The objective of this study is to assess, in high-risk patients aged 75 years and over undergoing high-risk surgery, the effectiveness of combined optimisation of anaesthesia involving goal-directed haemodynamic therapy (GDHT), LPV and electroencephalographic DAM on postoperative morbidity and mortality. The primary outcome of the study is a composite criterion associating major postoperative complications and mortality occurring within the 30 first postoperative days. The secondary outcomes are 1-year postoperative autonomy and mortality.

METHODS AND ANALYSIS

This prospective, randomised, controlled, multicentre trial using a stepped wedge cluster design will be conducted in 27 French university centres. Patients aged 75 years and over, undergoing femoral head fractures and major intraperitoneal or vascular elective surgeries will be included after informed consent. They will benefit from usual care in the 'control group' and from a combined optimisation of general anaesthesia involving GDHT, LPV and DAM in the 'optimisation group'. The cluster's crossover will be unidirectional, from control to optimisation, and randomised. Data will be recorded at inclusion, the day of surgery, 7 days, 30 days and 1year postoperatively and collected into a hosted electronic case report form. The primary outcome of the study is a composite criterion associating major postoperative complications and mortality occurring within the 30 first postoperative days. The secondary outcomes are 1- year postoperative autonomy and mortality.

ETHICS AND DISSEMINATION

This protocol was approved by the ethics committee Sud-Est 1 and the French regulatory agency. The finding of the trial will be disseminated through peer-reviewed journals and conferences TRIAL REGISTRATION NUMBER: NCT02668250; Pre-results.

A multicentre observational study on management of general anaesthesia in elderly patients at high-risk of postoperative adverse outcomes

INTRODUCTION

In elderly patients, goal-directed haemodynamic therapy (GDHT), depth of anaesthesia monitoring and lung-protective ventilation have been shown to improve postoperative outcomes. The aim of this study was to evaluate current practices concerning strategies of anaesthesia optimisation in patients aged≥75 years.

PATIENTS AND METHODS

A multicentre observational study was performed from February to May 2015 in 23 French academic centres. On 30 consecutive days in each centre, patients≥75 years with at least one major comorbidity undergoing elective or emergency procedures (femoral-neck fractures surgery, intraperitoneal abdominal surgery or vascular surgery) were included. Patient characteristics and data related to GHDT, management of hypotension, monitoring of temperature and depth of anaesthesia, lung ventilation, point of care haemoglobin testing were collected.

RESULTS

In total, 807 patients were included. Only 2% of patients [95% CI: 1-3] received GHDT in full accordance with guidelines. Depth of anaesthesia monitoring was largely performed (53% [95% CI: 50-56]). The multifaceted strategy of lung-protective ventilation combining low tidal volumes (6-8mL/kg), PEEP of 5-8cm cmH₂O, and repeated recruitment manoeuvres, was performed in only 4% [95% CI: 3-5] of patients. A centre effect was a major determinant of variation concerning implementation of these strategies.

DISCUSSION

In patients'≥75 years, strategies of anaesthesia optimisation are not in accordance with eligible guidelines. Implementation of these techniques varies independently of factors related to the patient or the type of surgery and may be dependent on the generated constraints.

Multi-parametric functional hemodynamic optimization improves postsurgical outcome after intermediate risk open gastrointestinal surgery: a randomized controlled trial

BACKGROUND

Perioperative goal directed therapy (pGDT) using flow monitoring has been associated with improved outcomes. However, its protocols are often based on stroke volume only: as a target for fluid loading, inotropic support and vasopressors (via mathematical coupling of systemic vascular resistance). In this trial, we have tested the multi-parametric pGDT protocol based on esophageal Doppler variables (corrected flow time, peak velocity) in intermediate-to-high risk patients undergoing gastrointestinal surgery.

METHODS

Intermediate-to-high risk patients undergoing gastrointestinal surgery were randomized to standard care (control) or multi-parametric pGDT (intervention). Postoperative complications and death rate as well as hospital length of stay were assessed as primary and secondary outcomes.

RESULTS

Overall, 140 patients (intervention, N.=71, and control, N.=69) were included and randomized out of 197 eligible. Higher vasoactive/inotropic drug use and lower fluid balance were observed in the intervention group leading to favorable hemodynamic profile. The pGDT intervention was associated with improved primary outcome (28 days mortality and morbidity defined as occurrence of any defined complication) - 20 patients (28.2%) versus 32 (46.4%) in the control group (P=0.036); RR 0.61 (95% CI: 0.39-0.95), P=0.03. No differences in mortality and hospital length of stay were observed between groups.

CONCLUSIONS

In this monocentric trial the multi-parametric pGDT protocol based on domain specific functional hemodynamic parameters was associated with lower rate of postoperative complications in intermediate-to-high risk patients undergoing scheduled gastrointestinal procedures.

Flow-directed vs. goal-directed strategy for management of hemodynamics

PURPOSE OF REVIEW

For the past 15 years, there has been a strong push to use goal-directed protocols for resuscitating critically ill patients and to manage perioperative patients. However, recent large clinical trials have failed to find evidence of improved outcome with this approach.

RECENT FINDINGS

A striking feature in the recent three large prospective randomized trials of septic patients and the one in high-risk perioperative patients is that outcomes in the control groups have markedly improved. This implies improvement in care and clinical acumen. Perhaps the clinical approach should be more toward further helping clinicians with their clinical choices. A good example is cardiac output. The objective of most hemodynamic interventions is to increase cardiac output. It would thus make sense to assess what happened to cardiac output after the intervention to determine if the intervention actually increased cardiac output. If it did not, another therapy should be chosen. I call this a flow-directed responsive protocol.

SUMMARY

A clinical approach that uses monitored values such as cardiac output as a feedback tool to evaluate the response to therapeutic interventions in individual patients may be better than protocols that set fixed targets for all study participants.

Cardiac output-based fluid optimization for kidney transplant recipients: a proof-of-concept trial

PURPOSE

Intravenous fluid management for deceased donor kidney transplantation is an important, modifiable risk factor for delayed graft function (DGF). The primary objective of this study was to determine if goal-directed fluid therapy using esophageal Doppler monitoring (EDM) to optimize stroke volume (SV) would alter the amount of fluid given.

METHODS

This randomized, proof-of-concept trial enrolled 50 deceased donor renal transplant recipients. Data collected included patient characteristics, fluid administration, hemodynamics, and complications. The EDM was used to optimize SV in the EDM group. In the control group, fluid management followed the current standard of practice. The groups were compared for the primary outcome of total intraoperative fluid administered.

RESULTS

There was no difference in the mean (standard deviation) volume of intraoperative fluid administered to the 24 control and 26 EDM patients [2,307 (750) mL vs 2,675 (842) mL, respectively; mean difference, 368 mL; 95% confidence interval (CI), - 87 to + 823; P = 0.11]. The incidence of complications in the control and EDM groups was similar (15/24 vs 17/26, respectively; P = 0.99), as was the incidence of delayed graft failure (8/24 vs 11/26, respectively; P = 0.36).

CONCLUSIONS

Goal-directed fluid therapy did not alter the volume of fluid administered or the incidence of complications. This proof-of-concept trial provides needed data for conducting a larger trial to determine the influence of fluid therapy on the incidence in DGF in deceased donor kidney transplantation.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02512731). Registered 31 July 2015.

Systematic Review and Meta-analysis of Objective Assessment of Physical Fitness in Patients Undergoing Colorectal Cancer Surgery

BACKGROUND

Gas exchange-derived variables obtained from cardiopulmonary exercise testing allow objective assessment of functional capacity and hence physiological reserve to withstand the stressors of major surgery. Field walk tests provide an alternate means for objective assessment of functional capacity that may be cheaper and have greater acceptability, in particular, in elderly patients.

OBJECTIVE

This systematic review evaluated the predictive value of cardiopulmonary exercise testing and field walk tests in surgical outcomes after colorectal surgery.

DATA SOURCE

A systematic search was undertaken using Medline, PubMed, Embase, CINAHL, and PEDro.

STUDY SELECTION

Adult patients who had cardiopulmonary exercise testing and/or field walk test before colorectal surgery were included.

MAIN OUTCOME MEASURE

The primary outcomes measured were hospital length of stay and postoperative morbidity and mortality.

RESULTS

A total of 7 studies with a cohort of 1418 patients who underwent colorectal surgery were identified for inclusion in a qualitative analysis. Both pooled oxygen consumption at anaerobic threshold (range, 10.1-11.1 mL·kg·min) and peak oxygen consumption (range, 16.7-18.6 mL·kg·min) were predictive of complications (OR for anaerobic threshold, 0.76; 95% CI, 0.66-0.85, p<0.0001; OR for peak oxygen consumption, 0.76; 95% CI, 0.67-0.85, p<0.0001). Patients had significant increased risk of developing postoperative complications if their anaerobic threshold was below this cut point (p<0.001). However, it was not predictive of anastomotic leak (p = 0.644). Shorter distance (<250 m) walked in incremental shuttle walk test, lower anaerobic threshold, and lower peak oxygen consumption were associated with prolonged hospital length of stay, which was closely related to the development of complications.

CONCLUSIONS

Variables derived from cardiopulmonary exercise testing are predictive of postoperative complications and hospital length of stay. Currently, there are insufficient data to support the predictive role of the field walk test in colorectal surgery.

Doppler-guided goal-directed fluid therapy does not affect intestinal cell damage but increases global gastrointestinal perfusion in colorectal surgery: a randomized controlled trial

AIM

Individualized, goal-directed fluid therapy (GDFT), based on Doppler measurements of stroke volume, has been proposed as a treatment strategy in terms of reducing complications, mortality and length of hospital stay in major bowel surgery. We studied the effect of Doppler-guided GDFT on intestinal damage as compared with standard postoperative fluid replacement.

METHOD

Patients undergoing elective colorectal resection for malignancy were randomized either to standard intra- and postoperative fluid therapy or to standard fluid therapy with additional Doppler-guided GDFT. The primary outcome was intestinal epithelial cell damage measured by plasma levels of intestinal fatty acid-binding protein (I-FABP). Global gastrointestinal perfusion was measured by gastric tonometry, expressed as regional (gastric) minus arterial CO₂ -gap (P_r-a CO₂ -gap).

RESULTS

I-FABP levels were not significantly different between the intervention group and the control group (respectively, 440.8 (251.6) pg/ml and 522.4 (759.9) pg/ml, P = 0.67). Mean areas under the curve (AUCs) of intra-operative P_r-a CO₂ -gaps were significantly lower in the intervention group than in the control group (P = 0.01), indicating better global gastrointestinal perfusion in the intervention group. Moreover, the mean intra-operative P_r-a CO₂ -gap peak in the intervention group was 0.5 (1.0) kPa, which was significantly lower than the mean peak in the control group, of 1.4 (1.4) kPa (P = 0.03).

CONCLUSION

Doppler-guided GDFT during and in the first hours after elective colorectal surgery for malignancy increases global gastrointestinal perfusion, as measured by P_r-a CO₂ -gap.

Feasibility research of non-invasive methods for interstitial fluid level measurement

This article explores a non-invasive method to determine interstitial fluid level and pressure in tissue. Interdigital electrodes were chosen by simulated results in software “Comsol multiphysis 4.3a”. Environment model similar to human body was created. Measurements were carried out at different situations which can occur during preoperative and afterwards surgery. Non-invasive method decreases possibility of infection and will improve recovery process in postoperative period.

Comparison of risk-scoring systems in the prediction of outcome after liver resection

Background

Risk prediction techniques commonly used in liver surgery include the American Society of Anesthesiologists (ASA) grading, Charlson Comorbidity Index (CCI) and cardiopulmonary exercise tests (CPET). This study compares the utility of these techniques along with the number of segments resected as predictive tools in liver surgery.

Methods

A review of a unit database of patients undergoing liver resection between February 2008 and January 2015 was undertaken. Patient demographics, ASA, CCI and CPET variables were recorded along with resection size. Clavien-Dindo grade III–V complications were used as a composite outcome in analyses. Association between predictive variables and outcome was assessed by univariate and multivariate techniques.

Results

One hundred and seventy-two resections in 168 patients were identified. Grade III–V complications occurred after 42 (24.4%) liver resections. In univariate analysis of CPET variables, ventilatory equivalents for CO₂ (VEqCO₂) was associated with outcome. CCI score, but not ASA grade, was also associated with outcome. In multivariate analysis, the odds ratio of developing grade III–V complications for incremental increases in VEqCO₂, CCI and number of liver segments resected were 1.09, 1.49 and 2.94, respectively.

Conclusions

Of the techniques evaluated, resection size provides the simplest and most discriminating predictor of significant complications following liver surgery.

Preoperative fluid retention increases blood loss during major open abdominal surgery

BACKGROUND

Quantification of renal fluid conservation is possible by urine analysis, and the results can indicate dehydration. The present report sought to determine whether this fluid retention correlates with fluid requirements during major abdominal surgeries that have estimated operating times ≥ 2 h.

METHODS

Urine colour, specific weight, osmolality and creatinine concentration were used to calculate a composite "fluid retention index" (FRI) in 97 patients prior to major abdominal surgery. Goal-directed fluid volume optimization, with hydroxyethyl starch supplemented with a background administration of crystalloid fluid, was used.

RESULTS

The median preoperative FRI was 3.0. Fluid retention, considered as present when FRI ≥ 3.5, was found in 37% of the patients. Fluid retention was followed by a significantly larger blood loss (+ 125%; 450 vs. 200 ml), higher haemorrhage rate (+ 41%; 123 vs. 87 ml/h) and greater need for both colloid (+ 43%; 1.43 vs. 1.00 l) and crystalloid (+ 18%; 1.28 vs. 1.08 l) fluids. Despite the larger blood loss, the total fluid balance was more positive after surgery in the dehydrated patients (+ 26%; 1.91 vs. 1.51 l; P < 0.02).

CONCLUSIONS

Preoperative fluid retention, as detected in a urine sample, was associated with a greater blood loss and a more positive fluid balance during major abdominal surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01458678.

Goal-directed Fluid Therapy Does Not Reduce Primary Postoperative Ileus after Elective Laparoscopic Colorectal Surgery: A Randomized Controlled Trial

BACKGROUND

Inadequate perioperative fluid therapy impairs gastrointestinal function. Studies primarily evaluating the impact of goal-directed fluid therapy on primary postoperative ileus are missing. The objective of this study was to determine whether goal-directed fluid therapy reduces the incidence of primary postoperative ileus after laparoscopic colorectal surgery within an Enhanced Recovery After Surgery program.

METHODS

Randomized patient and assessor-blind controlled trial conducted in adult patients undergoing laparoscopic colorectal surgery within an Enhanced Recovery After Surgery program. Patients were assigned randomly to receive intraoperative goal-directed fluid therapy (goal-directed fluid therapy group) or fluid therapy based on traditional principles (control group). Primary postoperative ileus was the primary outcome.

RESULTS

One hundred twenty-eight patients were included and analyzed (goal-directed fluid therapy group: n = 64; control group: n = 64). The incidence of primary postoperative ileus was 22% in the goal-directed fluid therapy and 22% in the control group (relative risk, 1; 95% CI, 0.5 to 1.9; P = 1.00). Intraoperatively, patients in the goal-directed fluid therapy group received less intravenous fluids (mainly less crystalloids) but a greater volume of colloids. The increase of stroke volume and cardiac output was more pronounced and sustained in the goal-directed fluid therapy group. Length of hospital stay, 30-day postoperative morbidity, and mortality were not different.

CONCLUSIONS

Intraoperative goal-directed fluid therapy compared with fluid therapy based on traditional principles does not reduce primary postoperative ileus in patients undergoing laparoscopic colorectal surgery in the context of an Enhanced Recovery After Surgery program. Its previously demonstrated benefits might have been offset by advancements in perioperative care.

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 added value of cardiac index and pulse pressure variation monitoring to mean arterial pressure-guided volume therapy in moderate-risk abdominal surgery (COGUIDE): a pragmatic multicentre randomised controlled trial

There is disagreement regarding the benefits of goal-directed therapy in moderate-risk abdominal surgery. Therefore, we tested the hypothesis that the addition of non-invasive cardiac index and pulse pressure variation monitoring to mean arterial pressure-based goal-directed therapy would reduce the incidence of postoperative complications in patients having moderate-risk abdominal surgery. In this pragmatic multicentre randomised controlled trial, we randomly allocated 244 patients by envelope drawing in a 1:1 fashion, stratified per centre. All patients had mean arterial pressure, cardiac index and pulse pressure variation measured continuously. In one group, healthcare professionals were blinded to cardiac index and pulse pressure variation values and were asked to guide haemodynamic therapy only based on mean arterial pressure (control group). In the second group, cardiac index and pulse pressure variation values were displayed and kept within target ranges following a pre-defined algorithm (CI-PPV group). The primary endpoint was the incidence of postoperative complications within 30 days. One hundred and seventy-five patients were eligible for final analysis. Overall complication rates were similar (42/94 (44.7%) vs. 38/81 (46.9%) in the control and CI-PPV groups, respectively; p = 0.95). The CI-PPV group had lower mean (SD) pulse pressure variation values (9.5 (2.0)% vs. 11.9 (4.6)%; p = 0.003) and higher mean (SD) cardiac indices (2.76 (0.62) l min^-1 .m^-2 vs. 2.53 (0.66) l min^-1 .m^-2 ; p = 0.004) than the control group. In moderate-risk abdominal surgery, we observed no additional value of cardiac index and pulse pressure variation-guided haemodynamic therapy to mean arterial pressure-guided volume therapy with regard to postoperative complications.

Effect of goal-directed therapy on outcome after esophageal surgery: A quality improvement study

Background

Goal-directed therapy (GDT) can reduce postoperative complications in high-risk surgery patients. It is uncertain whether GDT has the same benefits in patients undergoing esophageal surgery. Goal of this Quality Improvement study was to evaluate the effects of a stroke volume guided GDT on post-operative outcome.

Methods and findings

We compared the postoperative outcome of patients undergoing esophagectomy before (99 patients) and after (100 patients) implementation of GDT. There was no difference in the proportion of patients with a complication (56% vs. 54%, p = 0.82), hospital stay and mortality. The incidence of prolonged ICU stay (>48 hours) was reduced (28% vs. 12, p = .005) in patients treated with GDT. Secondary analysis of complication rate showed a decrease in pneumonia (29 vs. 15%, p = .02), mediastinal abscesses (12 vs. 3%, p = .02), and gastric tube necrosis (5% vs. 0%, p = .03) in patients treated with GDT. Patients in the GDT group received significantly less fluids but received more colloids.

Conclusions

The implementation of GDT during esophagectomy was not associated with reductions in overall morbidity, mortality and hospital length of stay. However, we observed a decrease in pneumonia, mediastinal abscesses, gastric tube necrosis, and ICU length of stay.

Targeting urine output and 30-day mortality in goal-directed therapy: a systematic review with meta-analysis and meta-regression

Background

Oliguria is associated with a decreased kidney- and organ perfusion, leading to organ damage and increased mortality. While the effects of correcting oliguria on renal outcome have been investigated frequently, whether urine output is a modifiable risk factor for mortality or simply an epiphenomenon remains unclear. We investigated whether targeting urine output, defined as achieving and maintaining urine output above a predefined threshold, in hemodynamic management protocols affects 30-day mortality in perioperative and critical care.

Methods

We performed a systematic review with a random-effects meta-analyses and meta-regression based on search strategy through MEDLINE, EMBASE and references in relevant articles. We included studies comparing conventional fluid management with goal-directed therapy and reporting whether urine output was used as target or not, and reporting 30-day mortality data in perioperative and critical care.

Results

We found 36 studies in which goal-directed therapy reduced 30-day mortality (OR 0.825; 95% CI 0.684-0.995; P = 0.045). Targeting urine output within goal-directed therapy increased 30-day mortality (OR 2.66; 95% CI 1.06-6.67; P = 0.037), but not in conventional fluid management (OR 1.77; 95% CI 0.59-5.34; P = 0.305). After adjusting for operative setting, hemodynamic monitoring device, underlying etiology, use of vasoactive medication and year of publication, we found insufficient evidence to associate targeting urine output with a change in 30-day mortality (goal-directed therapy: OR 1.17; 95% CI 0.54-2.56; P = 0.685; conventional fluid management: OR 0.74; 95% CI 0.39-1.38; P = 0.334).

Conclusions

The principal finding of this meta-analysis is that after adjusting for confounders, there is insufficient evidence to associate targeting urine output with an effect on 30-day mortality. The paucity of direct data illustrates the need for further research on whether permissive oliguria should be a key component of fluid management protocols.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0316-4) contains supplementary material, which is available to authorized users.

Perioperative fluid management: From physiology to improving clinical outcomes

Perioperative fluid management is a key component in the care of the surgical patient. It is an area that has seen significant changes and developments, however there remains a wide disparity in practice between clinicians. Historically, patients received large volumes of intravenous fluids perioperatively. The concept of goal directed therapy was then introduced, with the early studies showing significant improvements in morbidity and mortality. The current focus is on fluid therapy guided by an individual patient's physiology. A fluid challenge is commonly performed as part of an assessment of a patient's fluid responsiveness. There remains wide variation in how clinicians perform a fluid challenge and this review explores the evidence for how to administer an effective challenge that is both reliable and reproducible. The methods for monitoring cardiac output have evolved from the pulmonary artery catheter to a range of less invasive techniques. The different options that are available for perioperative use are considered. Fluid status can also be assessed by examining the microcirculation and the importance of recognising the possibility of a lack of coherence between the macro and microcirculation is discussed. Fluid therapy needs to be targeted to specific end points and individualised. Not all patients who respond to a fluid challenge will necessarily require additional fluid administration and care should be aimed at identifying those who do. This review aims to explain the underlying physiology and describe the evidence base and the changes that have been seen in the approach to perioperative fluid therapy.

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.

Goal directed fluid therapy decreases postoperative morbidity but not mortality in major non-cardiac surgery: a meta-analysis and trial sequential analysis of randomized controlled trials

BACKGROUND AND AIMS

Optimum perioperative fluid administration may improve postoperative outcome after major surgery. This meta-analysis and systematic review has been aimed to determine the effect of dynamic goal directed fluid therapy (GDFT) on postoperative morbidity and mortality in non-cardiac surgical patients.

MATERIAL AND METHODS

Meta-analysis of published prospective randomized controlled trials where GDFT based on non-invasive flow based hemodynamic measurement has been compared with a standard care. Data from 41 prospective randomized trials have been included in this study.

RESULTS

Use of GDFT in major surgical patients does not decrease postoperative hospital/30-day mortality (OR 0.70, 95 % CI 0.46-1.08, p = 0.11) length of post-operative hospital stay (SMD -0.14; 95 % CI -0.28, 0.00; p = 0.05) and length of ICU stay (SMD -0.12; 95 % CI -0.28, 0.04; p = 0.14). However, number of patients having at least one postoperative complication is significantly lower with use of GDFT (OR 0.57; 95 % CI 0.43, 0.75; p < 0.0001). Abdominal complications (p = 0.008), wound infection (p = 0.002) and postoperative hypotension (p = 0.04) are also decreased with used of GDFT as opposed to a standard care. Though patients who received GDFT were infused more colloid (p < 0.0001), there is no increased risk of heart failure or pulmonary edema and renal failure.

CONCLUSION

GDFT in major non- cardiac surgical patients has questionable benefit over a standard care in terms of postoperative mortality, length of hospital stay and length of ICU stay. However, incidence of all complications including wound infection, abdominal complications and postoperative hypotension is reduced.

Goal directed hemodynamic therapy based in esophageal Doppler flow parameters: A systematic review, meta-analysis and trial sequential analysis

BACKGROUND

Numerous studies have compared perioperative esophageal doppler monitoring (EDM) guided intravascular volume replacement strategies with conventional clinical volume replacement in surgical patients. The use of the EDM within hemodynamic algorithms is called 'goal directed hemodynamic therapy' (GDHT).

METHODS

Meta-analysis of the effects of EDM guided GDHT in adult non-cardiac surgery on postoperative complications and mortality using PRISMA methodology. A systematic search was performed in Medline, PubMed, EMBASE, and the Cochrane Library (last update, March 2015).

INCLUSION CRITERIA

Randomized clinical trials (RCTs) in which perioperative GDHT was compared to other fluid management.

PRIMARY OUTCOMES

Overall complications.

SECONDARY OUTCOMES

Mortality; number of patients with complications; cardiac, renal and infectious complications; incidence of ileus. Studies were subjected to quantifiable analysis, pre-defined subgroup analysis (stratified by surgery, type of comparator and risk); pre-defined sensitivity analysis and trial sequential analysis (TSA).

RESULTS

Fifty six RCTs were initially identified, 15 fulfilling the inclusion criteria, including 1,368 patients. A significant reduction was observed in overall complications associated with GDHT compared to other fluid therapy (RR=0.75; 95%CI: 0.63-0.89; P=0.0009) in colorectal, urological and high-risk surgery compared to conventional fluid therapy. No differences were found in secondary outcomes, neither in other subgroups. The impact on preventing the development of complications in patients using EDM is high, causing a relative risk reduction (RRR) of 50% for a number needed to treat (NNT)=6.

CONCLUSIONS

GDHT guided by EDM decreases postoperative complications, especially in patients undergoing colorectal surgery and high-risk surgery. However, no differences versus restrictive fluid therapy and in intermediate-risk patients were found.

Molecular Mechanisms Linking Autonomic Dysfunction and Impaired Cardiac Contractility in Critical Illness

OBJECTIVES

Molecular mechanisms linking autonomic dysfunction with poorer clinical outcomes in critical illness remain unclear. We hypothesized that baroreflex dysfunction alone is sufficient to cause cardiac impairment through neurohormonal activation of (nicotinamide adenine dinucleotide phosphate oxidase dependent) oxidative stress resulting in increased expression of G-protein-coupled receptor kinase 2, a key negative regulator of cardiac function.

DESIGN

Laboratory/clinical investigations.

SETTING

University laboratory/medical centers.

SUBJECTS

Adult rats; wild-type/nicotinamide adenine dinucleotide phosphate oxidase subunit-2-deficient mice; elective surgical patients.

INTERVENTIONS

Cardiac performance was assessed by transthoracic echocardiography following experimental baroreflex dysfunction (sino-aortic denervation) in rats and mice. Immunoblots assessed G-protein-coupled receptor recycling proteins expression in rodent cardiomyocytes and patient mononuclear leukocytes. In surgical patients, heart rate recovery after cardiopulmonary exercise testing, time/frequency measures of parasympathetic variables were related to the presence/absence of baroreflex dysfunction (defined by spontaneous baroreflex sensitivity of <6 ms mm Hg). The associations of baroreflex dysfunction with intraoperative cardiac function and outcomes were assessed.

MEASUREMENTS AND MAIN RESULTS

Experimental baroreflex dysfunction in rats and mice resulted in impaired cardiac contractility and upregulation of G-protein-coupled receptor kinase 2 expression. In mice, genetic deficiency of gp91 nicotinamide adenine dinucleotide phosphate oxidase subunit-2 prevented upregulation of G-protein-coupled receptor kinase 2 expression in conditions of baroreflex dysfunction and preserved cardiac function. Baroreflex dysfunction was present in 81 of 249 patients (32.5%) and was characterized by lower parasympathetic tone and increased G-protein-coupled receptor kinase 2 expression in mononuclear leukocytes. Baroreflex dysfunction in patients was also associated with impaired intraoperative cardiac contractility. Critical illness and mortality were more frequent in surgical patients with baroreflex dysfunction (relative risk, 1.66 [95% CI, 1.16-2.39]; p = 0.006).

CONCLUSIONS

Reduced baroreflex sensitivity is associated with nicotinamide adenine dinucleotide phosphate oxidase subunit-2-mediated upregulation of G-protein-coupled receptor kinase 2 expression in cardiomyocytes and impaired cardiac contractility. Autonomic dysfunction predisposes patients to the development of critical illness and increases mortality.

Ratio of intra-operative fluid to anesthesia time and its impact on short term perioperative outcomes following gastrectomy for cancer: A retrospective cohort study

BACKGROUND

This study evaluates the short-term impact of fluid administration during gastrectomy for cancer.

METHODS

A multi-institutional database of patients undergoing gastrectomy for cancer from three tertiary centers was reviewed. Logistic and linear regression analyses were performed.

RESULTS

205 patients were included. The majority of patients (n = 116, 57%) underwent proximal or total gastrectomy. Median anesthesia time was 280 min (range 95-691 min). Median intraoperative crystalloid administration was 2901 ml (range 500-10,700 ml). Median colloid administration was 0 (range 0-3835 ml), although only 66 patients (32%) received colloid. On multivariate analysis, patients who received <10.0 ml total fluid per minute of anesthesia had a significantly higher risk of complications (OR 4.12, p = 0.010). Crystalloid and total fluid administration ratios did not significantly affect LOS or discharge disposition.

CONCLUSIONS

Restricting intra-operative fluid resuscitation to <10 ml total fluid per minute anesthesia is associated with an increased risk of complications in patients undergoing gastrectomy for cancer.

Intraoperative Goal-directed Fluid Therapy in Elective Major Abdominal Surgery: A Meta-analysis of Randomized Controlled Trials

Objectives:

To compare the effects of intraoperative goal-directed fluid therapy (GDFT) with conventional fluid therapy, and determine whether there was a difference in outcome between studies that did and did not use Enhanced Recovery After Surgery (ERAS) protocols.

Methods:

Meta-analysis of randomized controlled trials of adult patients undergoing elective major abdominal surgery comparing intraoperative GDFT versus conventional fluid therapy. The outcome measures were postoperative morbidity, length of stay, gastrointestinal function and 30-day mortality.

Results:

A total of 23 studies were included with 2099 patients: 1040 who underwent GDFT and 1059 who received conventional fluid therapy. GDFT was associated with a significant reduction in morbidity (risk ratio [RR] 0.76, 95% confidence interval [CI] 0.66–0.89, P = 0.0007), hospital length of stay (LOS; mean difference −1.55 days, 95% CI −2.73 to −0.36, P = 0.01), intensive care LOS (mean difference −0.63 days, 95% CI −1.18 to −0.09, P = 0.02), and time to passage of feces (mean difference −0.90 days, 95% CI −1.48 to −0.32 days, P = 0.002). However, no difference was seen in mortality, return of flatus, or risk of paralytic ileus. If patients were managed in an ERAS pathway, the only significant reductions were in intensive care LOS (mean difference −0.63 days, 95% CI −0.94 to −0.32, P < 0.0001) and time to passage of feces (mean difference −1.09 days, 95% CI −2.03 to −0.15, P = 0.02). If managed in a traditional care setting, a significant reduction was seen in both overall morbidity (RR 0.69, 95% CI 0.57 to −0.84, P = 0.0002) and total hospital LOS (mean difference −2.14, 95% CI −4.15 to −0.13, P = 0.04).

Conclusions:

GDFT may not be of benefit to all elective patients undergoing major abdominal surgery, particularly those managed in an ERAS setting.

Minimally Invasive Cardiac Output Monitoring: Agreement of Oesophageal Doppler, LiDCOrapid™ and Vigileo FloTrac™ Monitors in Non-Cardiac Surgery

There is lack of data about the agreement of minimally invasive cardiac output monitors, which make it impossible to determine if they are interchangeable or differ objectively in tracking physiological trends. We studied three commonly used devices: the oesophageal Doppler and two arterial pressure–based devices, the Vigileo FloTrac™ and LiDCOrapid™. The aim of this study was to compare the agreement of these three monitors in adult patients undergoing elective non-cardiac surgery. Measurements were taken at baseline and after predefined clinical interventions of fluid, metaraminol or ephedrine bolus. From 24 patients, 131 events, averaging 5.2 events per patient, were analysed. The cardiac index of LiDCOrapid versus FloTrac had a mean bias of −6.0% (limits of agreement from −51% to 39%) and concordance of over 80% to the three clinical interventions. The cardiac index of Doppler versus LiDCOrapid and Doppler versus FloTrac, had an increasing negative bias at higher mean cardiac outputs and there was significantly poorer concordance to all interventions. Of the preload-responsive parameters, Doppler stroke volume index, Doppler systolic flow time and FloTrac stroke volume variation were fair at predicting fluid responsiveness while other parameters were poor. While there is reasonable agreement between the two arterial pressure–derived cardiac output devices (LiDCOrapid and Vigileo FloTrac), these two devices differ significantly to the oesophageal Doppler technology in response to common clinical intraoperative interventions, representing a limitation to how interchangeable these technologies are in measuring cardiac output.

Fluid therapy in the perioperative setting-a clinical review

BACKGROUND

Perioperative hypovolemia and fluid overload have effects on both complications following surgery and on patient survival. Therefore, the administration of intravenous fluids before, during, and after surgery at the right time and in the right amounts is of great importance. This review aims to analyze the literature concerning perioperative fluid therapy in abdominal surgery and to provide evidence-based recommendations for clinical practice.

RESULTS

Preoperative oral or intravenous administration of carbohydrate containing fluids has been shown to improve postoperative well-being and muscular strength and to reduce insulin resistance. Hence, the intake of fluid (preferably containing carbohydrates) should be encouraged up to 2 h prior to surgery in order to avoid dehydration. Excessive intravenous fluid administration adds to tissue inflammation and edema formation, thereby compromising tissue healing. During major abdominal surgery a "zero-balance" intraoperative fluid strategy aims at avoiding fluid overload (and comparable to the so-called restrictive approach) as well as goal-directed fluid therapy (GDT). Both proved to significantly reduce postoperative complications when compared to "standard fluid therapy". Trials comparing "restrictive" or zero-balance and GDT have shown equal results, as long as fluid overload is avoided in the GDT group as well (categorized as "zero-balance GDT"). It is possible that high-risk surgical patients, such as those undergoing acute surgery, may benefit from the continuous monitoring of circulatory status that the GDT provides. Data on this group of patients is not available at present, but trials are ongoing.

CONCLUSION

In elective surgery, the zero-balance approach has shown to reduce postoperative complications and is easily applied for most patients. It is less expensive and simpler than the zero-balance GDT approach and therefore recommended in this review. In outpatient surgery, 1-2 L of balanced crystalloids reduces postoperative nausea and vomiting and improves well-being.

Measurement of Exercise Tolerance before Surgery (METS) study: a protocol for an international multicentre prospective cohort study of cardiopulmonary exercise testing prior to major non-cardiac surgery

INTRODUCTION

Preoperative functional capacity is considered an important risk factor for cardiovascular and other complications of major non-cardiac surgery. Nonetheless, the usual approach for estimating preoperative functional capacity, namely doctors' subjective assessment, may not accurately predict postoperative morbidity or mortality. 3 possible alternatives are cardiopulmonary exercise testing; the Duke Activity Status Index, a standardised questionnaire for estimating functional capacity; and the serum concentration of N-terminal pro-B-type natriuretic peptide (NT pro-BNP), a biomarker for heart failure and cardiac ischaemia.

METHODS AND ANALYSIS

The Measurement of Exercise Tolerance before Surgery (METS) Study is a multicentre prospective cohort study of patients undergoing major elective non-cardiac surgery at 25 participating study sites in Australia, Canada, New Zealand and the UK. We aim to recruit 1723 participants. Prior to surgery, participants undergo symptom-limited cardiopulmonary exercise testing on a cycle ergometer, complete the Duke Activity Status Index questionnaire, undergo blood sampling to measure serum NT pro-BNP concentration and have their functional capacity subjectively assessed by their responsible doctors. Participants are followed for 1 year after surgery to assess vital status, postoperative complications and general health utilities. The primary outcome is all-cause death or non-fatal myocardial infarction within 30 days after surgery, and the secondary outcome is all-cause death within 1 year after surgery. Both receiver-operating-characteristic curve methods and risk reclassification table methods will be used to compare the prognostic accuracy of preoperative subjective assessment, peak oxygen consumption during cardiopulmonary exercise testing, Duke Activity Status Index scores and serum NT pro-BNP concentration.

ETHICS AND DISSEMINATION

The METS Study has received research ethics board approval at all sites. Participant recruitment began in March 2013, and 1-year follow-up is expected to finish in 2016. Publication of the results of the METS Study is anticipated to occur in 2017.

Variation in crystalloid administration: an analysis of 6248 patients undergoing major elective surgery

BACKGROUND

Large variations exist regarding the type and volume of fluid to be administered to patients. This study aimed to quantitate variations in the administration of crystalloid fluids at the level of the patient, provider, and procedure at a large, tertiary care center.

METHOD

Patients who underwent major cardiac, thoracic, or abdominal procedures between 2011 and 2014 were identified. Variations in crystalloid administration were compared by procedure and provider using a coefficient of variation (CV). Multivariable hierarchical linear modeling was performed to identify factors predictive of fluid administration and quantitate variation at the level of the patient and provider.

RESULTS

Among 6248 patients who met inclusion criteria, the average crystalloid volume was 25.8 mL kg(-1) m(2) h(-1), corresponding to a CV of 55%. Patients who underwent pancreatectomy received the highest corrected crystalloid volume (32.7 mL kg(-1) m(2) h(-1)), whereas those who underwent coronary artery bypass grafting received the lowest corrected crystalloid volume (14.7 mL kg(-1) m(2) h(-1)). Variations in fluid practices were noted between providers (corrected CV; 14.7%-97.1%) and within the practices of the same provider (corrected CV range; 24.1%-87.9%). On multivariable analysis, age and changes in hemoglobin concentration were associated with a higher crystalloid volume (both P < 0.05). Although over 90% of the variation was attributed to patient-level factors, approximately 10% was due to factors at level of the provider (surgeon: 5.8% versus anesthesiologist: 3.4%).

CONCLUSIONS

Wide variations were noted in crystalloid administration between procedures, providers, and within providers. Evidence-based practices and goal-directed therapies should be incorporated to avoid unwanted variations.

Agreement between Pleth Variability Index and oesophageal Doppler to predict fluid responsiveness

BACKGROUND

Optimisation of stroke volume using oesophageal Doppler is an established technique to guide intraoperative fluid therapy. The method has practical limitations and therefore alternative indices of fluid responsiveness, such as ventilator-induced variation in the pulse oximetric signal (Pleth Variability Index (PVI)) could be considered. We hypothesised that both methods predict fluid responsiveness in a similar way.

METHODS

Seventy-five patients scheduled for open major abdominal surgery were randomised to fluid optimisation using fluid bolus algorithms based on either PVI (n = 35) or Doppler (n = 39). All patients were monitored with both methods; the non-guiding method was blind. Primary endpoint was the concordance between the methods to predict fluid responsiveness. We also analysed the ability of each method to predict a stroke volume increase ≥ 10% after a fluid bolus, as well as the accumulated intraoperative bolus fluid volume.

RESULTS

PVI indicated a need for fluid in one-third of the situations when Doppler did so, Cohen's kappa = 0.03. A fluid bolus indicated by the PVI algorithm increased stroke volume by ≥ 10% in half the situations. The same was found for the Doppler algorithm. The mean total bolus volume given was 878 ml when the fluid management was governed by PVI compared to 826 ml with Doppler (P = 0.71).

CONCLUSION

PVI- and Doppler-based stroke volume optimisations agreed poorly, which did not affect the amount of fluid administered. None of the algorithms showed a good ability to predict fluid responsiveness. Our results do not support the fluid responsiveness concept.

Using cardiac output monitoring to guide perioperative haemodynamic therapy

PURPOSE OF REVIEW

The aim of this study was to review recent advances and evidence for the use of cardiac output monitors to guide perioperative haemodynamic therapy.

RECENT FINDINGS

There are multiple different cardiac output monitoring devices available for clinical use which are coupled with many different intervention protocols to manipulate perioperative haemodynamics. There is little evidence to demonstrate superiority of any one device. Previous small studies and meta-analyses have suggested that perioperative haemodynamic therapy guided by cardiac output monitoring improves outcomes after major surgery. Despite relatively low-quality evidence several national bodies have recommended 'perioperative goal-directed therapy' (GDT) as a standard of care.Recent larger trials of GDT have mostly failed to prove a benefit of GDT and one explanation for this is the increased quality of usual care that may be occurring because of initiatives such as enhanced recovery after surgery and the WHO Safer Surgery programmes.

SUMMARY

Perioperative GDT remains an exciting intervention to reduce significant morbidity following major surgery; however, it is not yet a proven standard of care. Further large pragmatic trials are required to demonstrate its effectiveness particularly in the era of enhanced recovery after surgery programmes.

Fluid Therapy: Double-Edged Sword during Critical Care?

Fluid therapy is still the mainstay of acute care in patients with shock or cardiovascular compromise. However, our understanding of the critically ill pathophysiology has evolved significantly in recent years. The revelation of the glycocalyx layer and subsequent research has redefined the basics of fluids behavior in the circulation. Using less invasive hemodynamic monitoring tools enables us to assess the cardiovascular function in a dynamic perspective. This allows pinpointing even distinct changes induced by treatment, by postural changes, or by interorgan interactions in real time and enables individualized patient management. Regarding fluids as drugs of any other kind led to the need for precise indication, way of administration, and also assessment of side effects. We possess now the evidence that patient centered outcomes may be altered when incorrect time, dose, or type of fluids are administered. In this review, three major features of fluid therapy are discussed: the prediction of fluid responsiveness, potential harms induced by overzealous fluid administration, and finally the problem of protocol-led treatments and their timing.