Haemodynamic optimisation in lower limb arterial surgery: room for improvement?

Restricted Versus Liberal Versus Goal-Directed Fluid Therapy for Non-vascular Abdominal Surgery: A Network Meta-Analysis and Systematic Review

Optimal perioperative fluid management is crucial, with over- or under-replacement associated with complications. There are many strategies for fluid therapy, including liberal fluid therapy (LFT), restrictive fluid therapy (RFT) and goal-directed fluid therapy (GDT), without a clear consensus as to which is better. We aimed to find out which is the more effective fluid therapy option in adult surgical patients undergoing non-vascular abdominal surgery in the perioperative period. This study is a systematic review and network meta-analysis (NMA) with node-splitting analysis of inconsistency, sensitivity analysis and meta-regression. We conducted a literature search of Pubmed, Cochrane Library, EMBASE, Google Scholar and Web of Science. Only studies comparing restrictive, liberal and goal-directed fluid therapy during the perioperative phase in major non-cardiac surgery in adult patients will be included. Trials on paediatric patients, obstetric patients and cardiac surgery were excluded. Trials that focused on goal-directed therapy monitoring with pulmonary artery catheters and venous oxygen saturation (SvO2), as well as those examining purely biochemical and laboratory end points, were excluded. A total of 102 randomised controlled trials (RCTs) and 78 studies (12,100 patients) were included. NMA concluded that goal-directed fluid therapy utilising FloTrac was the most effective intervention in reducing the length of stay (LOS) (surface under cumulative ranking curve (SUCRA) = 91%, odds ratio (OR) = -2.4, 95% credible intervals (CrI) = -3.9 to -0.85) and wound complications (SUCRA = 86%, OR = 0.41, 95% CrI = 0.24 to 0.69). Goal-directed fluid therapy utilising pulse pressure variation was the most effective in reducing the complication rate (SUCRA = 80%, OR = 0.25, 95% CrI = 0.047 to 1.2), renal complications (SUCRA = 93%, OR = 0.23, 95% CrI = 0.045 to 1.0), respiratory complications (SUCRA = 74%, OR = 0.42, 95% CrI = 0.053 to 3.6) and cardiac complications (SUCRA = 97%, OR = 0.067, 95% CrI = 0.0058 to 0.57). Liberal fluid therapy was the most effective in reducing the mortality rate (SUCRA = 81%, OR = 0.40, 95% CrI = 0.12 to 1.5). Goal-directed therapy utilising oesophageal Doppler was the most effective in reducing anastomotic leak (SUCRA = 79%, OR = 0.45, 95% CrI = 0.12 to 1.5). There was no publication bias, but moderate to substantial heterogeneity was found in all networks. In preventing different complications, except mortality, goal-directed fluid therapy was consistently more highly ranked and effective than standard (SFT), liberal or restricted fluid therapy. The evidence grade was low quality to very low quality for all the results, except those for wound complications and anastomotic leak.

Comparison of Goal-Directed Fluid Therapy using LiDCOrapid System with Regular Fluid Therapy in Patients Undergoing Spine Surgery as a Randomised Clinical Trial

Background

Goal-directed fluid therapy (GDFT) is a new concept to describe the cardiac output (CO) and stroke volume variation to guide intravenous fluid administration during surgery. LiDCOrapid (LiDCO, Cardiac Sensor System, UK Company Regd 2736561, VAT Regd 672475708) is a minimally invasive monitor that estimates the responsiveness of CO versus fluid infusion. We intend to find whether GDFT using the LiDCOrapid system can decrease the volume of intraoperative fluid therapy and facilitate recovery in patients undergoing posterior fusion spine surgeries in comparison to regular fluid therapy.

Methods

This study is a randomised clinical trial, and the design was parallel. Inclusion criteria for participants in this study were patients with comorbidities such as diabetes mellitus, hypertension, and ischemic heart disease undergoing spine surgery; exclusion criteria were patients with irregular heart rhythm or severe valvular heart disease. Forty patients with a previous history of medical comorbidities undergoing spine surgery were randomly and evenly assigned to receive either LiDCOrapid guided fluid therapy or regular fluid therapy. The volume of infused fluid was the primary outcome. The amount of bleeding, number of patients who needed packed red blood cell transfusion, base deficit, urine output, days of hospital length of stay and intensive care unit (ICU) admission, and time needed to start eating solids were monitored as secondary outcomes.

Results

The volume of infused crystalloid and urinary output in the LiDCO group was significantly lower than that of the control group (p = .001). Base deficit at the end of surgery was significantly better in the LiDCO group (p < .001). The duration of hospital length of stay in the LiDCO group was significantly shorter (p = .027), but the duration of ICU admission was not significantly different between the two groups.

Conclusion

Goal-directed fluid therapy using the LiDCOrapid system reduced the volume of intraoperative fluid therapy.

Goal-directed haemodynamic therapy (GDHT) in surgical patients: systematic review and meta-analysis of the impact of GDHT on post-operative pulmonary complications

Background

Perioperative goal-directed haemodynamic therapy (GDHT), defined as the administration of fluids with or without inotropes or vasoactive agents against explicit measured goals to augment blood flow, has been evaluated in many randomised controlled trials (RCTs) over the past four decades. Reported post-operative pulmonary complications commonly include chest infection or pneumonia, atelectasis, acute respiratory distress syndrome or acute lung injury, aspiration pneumonitis, pulmonary embolism, and pulmonary oedema. Despite the substantial clinical literature in this area, it remains unclear whether their incidence is reduced by GDHT. This systematic review aims to determine the effect of GDHT on the respiratory outcomes listed above, in surgical patients.

Methods

We searched the Cochrane Central Register for Controlled Trials (CENTRAL), MEDLINE, EMBASE, and clinical trial registries up until January 2020. We included all RCTs reporting pulmonary outcomes. The primary outcome was post-operative pulmonary complications and secondary outcomes were specific pulmonary complications and intra-operative fluid input. Data synthesis was performed on Review Manager and heterogeneity was assessed using I² statistics.

Results

We identified 66 studies with 9548 participants reporting pulmonary complications. GDHT resulted in a significant reduction in total pulmonary complications (OR 0.74, 95% CI 0.59 to 0.92). The incidence of pulmonary infections, reported in 45 studies with 6969 participants, was significantly lower in the GDHT group (OR 0.72, CI 0.60 to 0.86). Pulmonary oedema was recorded in 23 studies with 3205 participants and was less common in the GDHT group (OR 0.47, CI 0.30 to 0.73). There were no differences in the incidences of pulmonary embolism or acute respiratory distress syndrome. Sub-group analyses demonstrated: (i) benefit from GDHT in general/abdominal/mixed and cardiothoracic surgery but not in orthopaedic or vascular surgery; and (ii) benefit from fluids with inotropes and/or vasopressors in combination but not from fluids alone. Overall, the GDHT group received more colloid (+280 ml) and less crystalloid (−375 ml) solutions than the control group. Due to clinical and statistical heterogeneity, we downgraded this evidence to moderate.

Conclusions

This systematic review and meta-analysis suggests that the use of GDHT using fluids with inotropes and/or vasopressors, but not fluids alone, reduces the development of post-operative pulmonary infections and pulmonary oedema in general, abdominal and cardiothoracic surgical patients. This evidence was graded as moderate.

PROSPERO registry reference: CRD42020170361

Does goal-directed haemodynamic and fluid therapy improve peri-operative outcomes?: A systematic review and meta-analysis

BACKGROUND

Much uncertainty exists as to whether peri-operative goal-directed therapy is of benefit.

OBJECTIVES

To discover if peri-operative goal-directed therapy decreases mortality and morbidity in adult surgical patients.

DESIGN

An updated systematic review and random effects meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase and the Cochrane Library were searched up to 31 December 2016.

ELIGIBILITY CRITERIA

Randomised controlled trials enrolling adult surgical patients allocated to receive goal-directed therapy or standard care were eligible for inclusion. Trauma patients and parturients were excluded. Goal-directed therapy was defined as fluid and/or vasopressor therapy titrated to haemodynamic goals [e.g. cardiac output (CO)]. Outcomes included mortality, morbidity and hospital length of stay. Risk of bias was assessed using Cochrane methodology.

RESULTS

Ninety-five randomised trials (11 659 patients) were included. Only four studies were at low risk of bias. Modern goal-directed therapy reduced mortality compared with standard care [odds ratio (OR) 0.66; 95% confidence interval (CI) 0.50 to 0.87; number needed to treat = 59; N = 52; I = 0.0%]. In subgroup analysis, there was no mortality benefit for fluid-only goal-directed therapy, cardiac surgery patients or nonelective surgery. Contemporary goal-directed therapy also reduced pneumonia (OR 0.69; 95% CI, 0.51 to 0. 92; number needed to treat = 38), acute kidney injury (OR 0. 73; 95% CI, 0.58 to 0.92; number needed to treat = 29), wound infection (OR 0.48; 95% CI, 0.37 to 0.63; number needed to treat = 19) and hospital length of stay (days) (-0.90; 95% CI, -1.32 to -0.48; I = 81. 2%). No important differences in outcomes were found for the pulmonary artery catheter studies, after accounting for advances in the standard of care.

CONCLUSION

Peri-operative modern goal-directed therapy reduces morbidity and mortality. Importantly, the quality of evidence was low to very low (e.g. Grading of Recommendations, Assessment, Development and Evaluation scoring), and there was much clinical heterogeneity among the goal-directed therapy devices and protocols. Additional well designed and adequately powered trials on peri-operative goal-directed therapy are necessary.

Hemodynamic goal-directed therapy and postoperative kidney injury: an updated meta-analysis with trial sequential analysis

Background

Perioperative goal-directed therapy (GDT) reduces the risk of renal injury. However, several questions remain unanswered, such as target, kind of patients and surgery, and role of fluids and inotropes. We therefore update a previous analysis, including all studies published in the meanwhile, to clarify the clinical impact of this strategy on acute kidney injury.

Main body

Randomized controlled trials enrolling adult patients undergoing major surgery were considered. GDT was defined as perioperative monitoring and manipulation of hemodynamic parameters to reach normal or supranormal values by fluids alone or with inotropes. Trials comparing the effects of GDT and standard hemodynamic therapy were considered. Primary outcome was acute kidney injury, whichever definition was used. Meta-analytic techniques (analysis software RevMan, version 5.3) were used to combine studies, using random-effect odds ratios (OR) and 95% confidence intervals (CI). Trial sequential analyses were performed including all trials and considering only low risk of bias trials. Sixty-five trials with an overall sample of 9308 patients were included. OR for the development of renal injury was 0.64 (95% CI, 0.62–0.87; p = 0.0003), with no statistical heterogeneity. Trial sequential analyses and sensitivity analysis including studies with low risk of bias confirmed the main results. A significant decrease in renal injury rate was observed in studies that adopted cardiac output and oxygen delivery as hemodynamic target and that used both fluids and inotropes. The postoperative kidney injury rate was significantly lower in trials enrolling “high-risk” patients and major abdominal and orthopedic surgery.

Short conclusion

The present meta-analysis suggests that targeting GDT to perioperative systemic oxygen delivery, by means of fluids and inotropes, can be the best way to improve renal perfusion and oxygenation in high-risk patients undergoing major abdominal and orthopedic surgery.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2516-4) contains supplementary material, which is available to authorized users.

Perioperative goal-directed therapy: A systematic review without meta-analysis

BACKGROUND

Perioperative goal-directed therapy aims to optimise haemodynamics by titrating fluids, vasopressors and/or inotropes to predefined haemodynamic targets. Perioperative goal-directed therapy is a complex intervention composed of several independent component interventions. Trials on perioperative goal-directed therapy show conflicting results. We aimed to conduct a systematic review and meta-analysis to investigate the benefits and harms of perioperative goal-directed therapy.

METHODS

PubMED, EMBASE, Web of Science and Cochrane Library were searched. Trials were included if they had a perioperative goal-directed therapy protocol. The primary outcome was all-cause mortality. The first secondary outcome was serious adverse events excluding mortality. Risk of bias was assessed, and GRADE was used to evaluate quality of evidence.

RESULTS

One hundred and twelve randomised trials were included of which one trial (1%) had low risk of bias. Included trials varied in patients: types of surgery which was expected due to inclusion criteria; in intervention and comparison: timing of intervention, monitoring devices, haemodynamic variables, target values, use of fluids, vasopressors and/or inotropes as well as combinations of these within protocols; and in outcome: mortality was reported in 87 trials (78%). Due to substantial clinical heterogeneity also within the various types of surgery a meta-analysis of data, including subgroup analyses, as defined in our protocol was considered inappropriate.

CONCLUSION

Clinical heterogeneity in patients, interventions and outcomes in perioperative goal-directed therapy trials is too large to perform meta-analysis on all trials. Future trials and meta-analyses highly depend on universally agreed definitions on aspects beyond type of surgery of the complex intervention and its evaluation.

Association of conflicts of interest with the results and conclusions of goal-directed hemodynamic therapy research: a systematic review with meta-analysis

PURPOSE

The association between conflicts of interest (COI) and study results or article conclusions in goal-directed hemodynamic therapy (GDHT) research is unknown.

METHODS

Randomized controlled trials comparing GDHT with usual care were identified. COI were classified as industry sponsorship, author conflict, device loaner, none, or not reported. The association between COI and study results (complications and mortality) was assessed using both stratified meta-analysis and mixed effects meta-regression. The association between COI and an article's conclusion (graded as GDHT-favorable, neutral, or unfavorable) was investigated using logistic regression.

RESULTS

Of the 82 eligible articles, 43 (53%) had self-reported COI, and 50 (61%) favored GDHT. GDHT significantly reduced complications on the basis of the meta-analysis of studies with any type of COI, studies declaring no COI, industry-sponsored studies, and studies with author conflict but not on studies with a device loaner. However, no significant relationship between COI and the relative risk (GDHT vs. usual care) of developing complications was found on the basis of meta-regression (p = 0.25). No significant effect of GDHT was found on mortality. COI had a significant overall effect (p = 0.016) on the odds of having a GDHT-favorable vs. neutral conclusion based on 81 studies. Eighty-four percent of the industry-sponsored studies had a GDHT-favorable conclusion, while only 27% of the studies with a device loaner had the same conclusion grade.

CONCLUSIONS

The available evidence does not suggest a close relationship between COI and study results in GDHT research. However, a potential association may exist between COI and an article's conclusion in GDHT research.

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.

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.

Potential return on investment for implementation of perioperative goal-directed fluid therapy in major surgery: a nationwide database study

Background

Preventable postsurgical complications are increasingly recognized as a major clinical and economic burden. A recent meta-analysis showed a 17–29 % decrease in postoperative morbidity with goal-directed fluid therapy. Our objective was to estimate the potential economic impact of perioperative goal-directed fluid therapy.

Methods

We studied 204,680 adult patients from 541 US hospitals who had a major non-cardiac surgical procedure between January 2011 and June 2013. Hospital costs (including 30-day readmission costs) in patients with and without complications were extracted from the Premier Inc. research database, and potential cost-savings associated with a 17–29 % decrease in postoperative morbidity were estimated.

Results

A total of 76,807 patients developed one or more postsurgical complications (morbidity rate 37.5 %). In patients with and without complications, hospital costs were US$27,607 ± 32,788 and US$15,783 ± 12,282 (p < 0.0001), respectively. Morbidity rate was anticipated to decrease to 26.6–31.1 % with goal-directed fluid therapy, yielding potential gross cost-savings of US$153–263 million for the study period, US$61–105 million per year, or US$754–1286 per patient. Potential savings per patient were highly variable from one surgical procedure to the other, ranging from US$354–604 for femur and hip-fracture repair to US$3515–5996 for esophagectomies. When taking into account the volume of procedures, the total potential savings per year were the most significant (US$32–55 million) for colectomies.

Conclusions

Postsurgical complications occurred in more than one third of our study population and had a dramatic impact on hospital costs. With goal-directed fluid therapy, potential cost-savings per patient were US$754–1286. The highest cost-savings per year were observed for colectomies. These projections should help hospitals estimate the return on investment when considering the implementation of goal-directed fluid therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13741-015-0021-0) contains supplementary material, which is available to authorized users.

[Goal-directed hemodynamic therapy: Concepts, indications and risks]

Goal-directed hemodynamic therapy is becoming increasingly more interesting for anesthesiologists and intensive care physicians. Meta-analyses of studies evaluating perioperative therapy algorithms demonstrated a reduction of postoperative morbidity compared to the previous clinical practices. In this review article the basic concepts of goal-directed hemodynamic therapy and the principles of previously employed therapy algorithms are described and discussed. Furthermore, the questions of how these therapy strategies can be transferred into daily clinical practice and whether these therapeutic approaches might even bear risks for patients are elucidated.

Colloids versus crystalloids in objective-guided fluid therapy, systematic review and meta-analysis. Too early or too late to draw conclusions

INTRODUCTION

Several clinical trials on Goal directed fluid therapy (GDFT) were carried out, many of those using colloids in order to optimize the preload. After the decision of European Medicines Agency, there is such controversy regarding its use, benefits, and possible contribution to renal failure. The objective of this systematic review and meta-analysis is to compare the use of last-generation colloids, derived from corn, with crystalloids in GDFT to determine associated complications and mortality.

METHODS

A bibliographic research was carried out in MEDLINE PubMed, EMBASE and Cochrane Library, corroborating randomized clinical trials where crystalloids are compared to colloids in GDFT for major non-cardiac surgery in adults.

RESULTS

One hundred thirty references were found and among those 38 were selected and 29 analyzed; of these, six were included for systematic review and meta-analysis, including 390 patients. It was observed that the use of colloids is not associated with the increase of complications, but rather with a tendency to a higher mortality (RR [95% CI] 3.87 [1.121-13.38]; I(2)=0.0%; p=0.635).

CONCLUSIONS

Because of the limitations of this meta-analysis due to the small number of randomized clinical trials and patients included, the results should be taken cautiously, and the performance of new randomized clinical trials is proposed, with enough statistical power, comparing balanced and unbalanced colloids to balanced and unbalanced crystalloids, following the protocols of GDFT, considering current guidelines and suggestions made by groups of experts.

Tackling the economic burden of postsurgical complications: would perioperative goal-directed fluid therapy help?

INTRODUCTION

Pay-for-performance programs and economic constraints call for solutions to improve the quality of health care without increasing costs. Many studies have shown decreased morbidity in major surgery when perioperative goal directed fluid therapy (GDFT) is used. We assessed the clinical and economic burden of postsurgical complications in the University HealthSystem Consortium (UHC) in order to predict potential savings with GDFT.

METHODS

Data from adults who had a major surgical procedure in 2011 were screened in the UHC database. Thirteen post-surgical complications were tabulated. In-hospital mortality, hospital length of stay and costs from patients with and without complications were compared. The risk ratios reported by the most recent meta-analysis were used to estimate the potential reduction in post-surgical morbidity with GDFT. Potential cost-savings were calculated from the actual and anticipated morbidity rates.

RESULTS

A total of 75,140 patients met the search criteria, and 8,421 patients developed one or more post-surgical complications (morbidity rate 11.2%). In patients with and without complications, in-hospital mortality was 12.4% and 1.4% (P <0.001), mean hospital length of stay was 20.5 ± 20.1 days and 8.1 ± 7.1 days (P <0.001) and mean direct costs were $47,284 ± 49,170 and $17,408 ± 15,612 (P < 0.001), respectively. With GDFT, morbidity rate was projected to decrease to 8.0 - 9.3%, yielding gross costs savings of $43 M - $73 M for the study population or $569 - $970 per patient.

CONCLUSION

Postsurgical complications have a dramatic impact (+172%) on costs. Potential costs savings resulting from GDFT are substantial. Perioperative GDFT may be recommended not only to improve quality of care but also to decrease costs.

A review of intraoperative goal-directed therapy using arterial waveform analysis for assessment of cardiac output

Increasing evidence shows that goal-directed hemodynamic management can improve outcomes in surgical and intensive care settings. Arterial waveform analysis is one of the different techniques used for guiding goal-directed therapy. Multiple proprietary systems have developed algorithms for obtaining cardiac output from an arterial waveform, including the FloTrac, LiDCO, and PiCCO systems. These systems vary in terms of how they analyze the arterial pressure waveform as well as their requirements for invasive line placement and calibration. Although small-scale clinical trials using these monitors show promising data, large-scale multicenter trials are still needed to better determine how intraoperative goal-directed therapy with arterial waveform analysis can improve patient outcomes. This review provides a comparative analysis of the different arterial waveform monitors for intraoperative goal-directed therapy.

Clinical review: What are the best hemodynamic targets for noncardiac surgical patients?

Perioperative hemodynamic optimization, or goal-directed therapy (GDT), has been show to significantly decrease complications and risk of death in high-risk patients undergoing noncardiac surgery. An important aim of GDT is to prevent an imbalance between oxygen delivery and oxygen consumption in order to avoid the development of multiple organ dysfunction. The utilization of cardiac output monitoring in the perioperative period has been shown to improve outcomes if integrated into a GDT strategy. GDT guided by dynamic predictors of fluid responsiveness or functional hemodynamics with minimally invasive cardiac output monitoring is suitable for the majority of patients undergoing major surgery with expected significant volume shifts due to bleeding or other significant intravascular volume losses. For patients at higher risk of complications and death, such as those with advanced age and limited cardiorespiratory reserve, the addition of dobutamine or dopexamine to the treatment algorithm, to maximize oxygen delivery, is associated with better outcomes.