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.

Prediction of Fluid Responsiveness by the Effect of the Lung Recruitment Maneuver on the Perfusion Index in Mechanically Ventilated Patients During Surgery

Introduction

Excessive or inadequate fluid administration during perioperative period affects outcomes. Adjustment of volume expansion (VE) by performing fluid responsiveness (FR) test plays an important role in optimizing fluid infusion. Since changes in stroke volume (SV) during lung recruitment maneuver (LRM) can predict FR, and peripheral perfusion index (PI) is related to SV; therefore, we hypothesized that the changes in PI during LRM (ΔPILRM) could predict FR during perioperative period.

Methods

Patients who were scheduled for elective non-laparoscopic surgery under general anesthesia with a mechanical ventilator and who required VE (250 mL of crystalloid solution infusion over 10 min) were included. Before VE, LRM was performed by a continuous positive airway pressure of 30 cm H2O for 30 sec; hemodynamic variables with their changes (PI, obtained by pulse oximetry; and ΔPILRM, calculated by using [(PI before LRM—PI after LRM)/PI before LRM]*100) were obtained before and after LRM. After SV (measured by esophageal doppler) and PI had returned to the baseline values, VE was infused, and the values of these variables were recorded again, before and after VE. Fluid responders (Fluid-Res) were defined by an increase in SV ≥10% after VE. Receiver operating characteristic curves of the baseline values and ΔPILRM were constructed and reported as areas under the curve (AUC) with 95% confidence intervals, to predict FR.

Results

Of 32 mechanically ventilated adult patients included, 13 (41%) were in the Fluid-Res group. Before VE and LRM, there were no differences in the mean arterial pressure (MAP), heart rate, SV, and PI between patients in the Fluid-Res and fluid non-responders (Fluid-NonRes) groups. After LRM, SV, MAP, and, PI decreased in both groups, ΔPILRM was greater in the Fluid-Res group than in Fluid-NonRes group (55.2 ± 17.8% vs. 35.3 ± 17.3%, p < 0.001, respectively). After VE, only SV and cardiac index increased in the Fluid-Res group. ΔPILRM had the highest AUC [0.81 (0.66–0.97)] to predict FR with a cut-off value of 40% (sensitivity 92.3%, specificity 73.7%).

Conclusions

ΔPILRM can be applied to predict FR in mechanical ventilated patients during the perioperative period.

Perioperative restrictive versus goal-directed fluid therapy for adults undergoing major non-cardiac surgery

BACKGROUND

Perioperative fluid management is a crucial element of perioperative care and has been studied extensively recently; however, 'the right amount' remains uncertain. One concept in perioperative fluid handling is goal-directed fluid therapy (GDFT), wherein fluid administration targets various continuously measured haemodynamic variables with the aim of optimizing oxygen delivery. Another recently raised concept is that perioperative restrictive fluid therapy (RFT) may be beneficial and at least as effective as GDFT, with lower cost and less resource utilization.

OBJECTIVES

To investigate whether RFT may be more beneficial than GDFT for adults undergoing major non-cardiac surgery.

SEARCH METHODS

We searched the following electronic databases on 11 October 2019: Cochrane Central Register of Controlled Trials, in the Cochrane Libary; MEDLINE; and Embase. Additionally, we performed a targeted search in Google Scholar and searched trial registries (World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov) for ongoing and unpublished trials. We scanned the reference lists and citations of included trials and any relevant systematic reviews identified.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing perioperative RFT versus GDFT for adults (aged ≥ 18 years) undergoing major non-cardiac surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references for eligibility, extracted data, and assessed risk of bias. We resolved discrepancies by discussion and consulted a third review author if necessary. When necessary, we contacted trial authors to request additional information. We presented pooled estimates for dichotomous outcomes as risk ratios (RRs) with 95% confidence intervals (CIs), and for continuous outcomes as mean differences (MDs) with standard deviations (SDs). We used Review Manager 5 software to perform the meta-analyses. We used a fixed-effect model if we considered heterogeneity as not important; otherwise, we used a random-effects model. We used Poisson regression models to compare the average number of complications per person.

MAIN RESULTS

From 6396 citations, we included six studies with a total of 562 participants. Five studies were performed in participants undergoing abdominal surgery (including one study in participants undergoing cytoreductive abdominal surgery with hyperthermic intraperitoneal chemotherapy (HIPEC)), and one study was performed in participants undergoing orthopaedic surgery. In all studies, surgeries were elective. In five studies, crystalloids were used for basal infusion and colloids for boluses, and in one study, colloid was used for both basal infusion and boluses. Five studies reported the ASA (American Society of Anesthesiologists) status of participants. Most participants were ASA II (60.4%), 22.7% were ASA I, and only 16.9% were ASA III. No study participants were ASA IV. For the GDFT group, oesophageal doppler monitoring was used in three studies, uncalibrated invasive arterial pressure analysis systems in two studies, and a non-invasive arterial pressure monitoring system in one study. In all studies, GDFT optimization was conducted only intraoperatively. Only one study was at low risk of bias in all domains. The other five studies were at unclear or high risk of bias in one to three domains. RFT may have no effect on the rate of major complications compared to GDFT, but the evidence is very uncertain (RR 1.61, 95% CI 0.78 to 3.34; 484 participants; 5 studies; very low-certainty evidence). RFT may increase the risk of all-cause mortality compared to GDFT, but the evidence on this is also very uncertain (RD 0.03, 95% CI 0.00 to 0.06; 544 participants; 6 studies; very low-certainty evidence). In a post-hoc analysis using a Peto odds ratio (OR) or a Poisson regression model, the odds of all-cause mortality were 4.81 times greater with the use of RFT compared to GDFT, but the evidence again is very uncertain (Peto OR 4.81, 95% CI 1.38 to 16.84; 544 participants; 6 studies; very low-certainty evidence). Nevertheless, sensitivity analysis shows that exclusion of a study in which the final volume of fluid received intraoperatively was higher in the RFT group than in the GDFT group revealed no differences in mortality. Based on analysis of secondary outcomes, such as length of hospital stay (464 participants; 5 studies; very low-certainty evidence), surgery-related complications (364 participants; 4 studies; very low-certainty evidence), non-surgery-related complications (74 participants; 1 study; very low-certainty evidence), renal failure (410 participants; 4 studies; very low-certainty evidence), and quality of surgical recovery (74 participants; 1 study; very low-certainty evidence), GDFT may have no effect on the risk of these outcomes compared to RFT, but the evidence is very uncertain. Included studies provided no data on administration of vasopressors or inotropes to correct haemodynamic instability nor on cost of treatment.

AUTHORS' CONCLUSIONS

Based on very low-certainty evidence, we are uncertain whether RFT is inferior to GDFT in selected populations of adults undergoing major non-cardiac surgery. The evidence is based mainly on data from studies on abdominal surgery in a low-risk population. The evidence does not address higher-risk populations or other surgery types. Larger, higher-quality RCTs including a wider spectrum of surgery types and a wider spectrum of patient groups, including high-risk populations, are needed to determine effects of the intervention.