Crystalloids versus colloids for goal-directed fluid therapy in major surgery

Preliminary research on tailored fluid therapy in pigs: comparing customized ionic solutions with Hartmann's solution

BACKGROUND

Fluid therapy in veterinary medicine is pivotal for treating various conditions in pigs; however, standard solutions, such as Hartmann's solution, may not optimally align with pig physiology. This study explored the development and efficacy of a customized fluid therapy tailored to the ionic concentrations of pig blood, aiming to enhance treatment outcomes and safety in both healthy and diseased pigs.

RESULTS

The study involved two experiments: the first to assess the safety and stability of customized fluids in healthy pigs, and the second to evaluate the efficacy in pigs with clinical symptoms of dehydration. In healthy pigs, the administration of customized fluids showed no adverse effects, with slight alterations observed in pO2, hematocrit, and glucose levels in some groups. In symptomatic pigs, the customized fluid group did not show any improvement in clinical symptoms, with no significant changes in blood chemistry or metabolite levels compared to controls. The customized fluid group showed a mild increase in some values after administration, yet within normal physiological ranges. The study reported no significant improvements in clinical or dehydration status, attributing the observed variations in blood test results to the limited sample size and anaesthesia effects rather than fluid characteristics.

CONCLUSIONS

Customized fluid therapy, tailored to mimic the ionic concentrations of pig blood, appears to be a safe and potentially more effective alternative to conventional solutions such as Hartmann's solution for treating pigs under various health conditions. Further research with larger sample sizes and controlled conditions is recommended to validate these findings and to explore the full potential of customized fluid therapy in veterinary practice.

Goal-directed colloid versus crystalloid therapy and microcirculatory blood flow following ischemia/reperfusion

OBJECTIVE

Ischemia/reperfusion can impair microcirculatory blood flow. It remains unknown whether colloids are superior to crystalloids for restoration of microcirculatory blood flow during ischemia/reperfusion injury. We tested the hypothesis that goal-directed colloid - compared to crystalloid - therapy improves small intestinal, renal, and hepatic microcirculatory blood flow in pigs with ischemia/reperfusion injury.

METHODS

This was a randomized trial in 32 pigs. We induced ischemia/reperfusion by supra-celiac aortic-cross-clamping. Pigs were randomized to receive either goal-directed isooncotic hydroxyethyl-starch colloid or balanced isotonic crystalloid therapy. Microcirculatory blood flow was measured using Laser-Speckle-Contrast-Imaging. The primary outcome was small intestinal, renal, and hepatic microcirculatory blood flow 4.5 h after ischemia/reperfusion. Secondary outcomes included small intestinal, renal, and hepatic histopathological damage, macrohemodynamic and metabolic variables, as well as specific biomarkers of tissue injury, renal, and hepatic function and injury, and endothelial barrier function.

RESULTS

Small intestinal microcirculatory blood flow was higher in pigs assigned to isooncotic hydroxyethyl-starch colloid therapy than in pigs assigned to balanced isotonic crystalloid therapy (768.7 (677.2-860.1) vs. 595.6 (496.3-694.8) arbitrary units, p = .007). There were no important differences in renal (509.7 (427.2-592.1) vs. 442.1 (361.2-523.0) arbitrary units, p = .286) and hepatic (604.7 (507.7-701.8) vs. 548.7 (444.0-653.3) arbitrary units, p = .376) microcirculatory blood flow between groups. Pigs assigned to colloid - compared to crystalloid - therapy also had less small intestinal, but not renal and hepatic, histopathological damage.

CONCLUSIONS

Goal-directed isooncotic hydroxyethyl-starch colloid - compared to balanced isotonic crystalloid - therapy improved small intestinal, but not renal and hepatic, microcirculatory blood flow in pigs with ischemia/reperfusion injury. Whether colloid therapy improves small intestinal microcirculatory blood flow in patients with ischemia/reperfusion needs to be investigated in clinical trials.

The use of pulse pressure variation for predicting impairment of microcirculatory blood flow

Dynamic parameters of preload have been widely recommended to guide fluid therapy based on the principle of fluid responsiveness and with regard to cardiac output. An equally important aspect is however to also avoid volume-overload. This accounts particularly when capillary leakage is present and volume-overload will promote impairment of microcirculatory blood flow. The aim of this study was to evaluate, whether an impairment of intestinal microcirculation caused by volume-load potentially can be predicted using pulse pressure variation in an experimental model of ischemia/reperfusion injury. The study was designed as a prospective explorative large animal pilot study. The study was performed in 8 anesthetized domestic pigs (German landrace). Ischemia/reperfusion was induced during aortic surgery. 6 h after ischemia/reperfusion-injury measurements were performed during 4 consecutive volume-loading-steps, each consisting of 6 ml kg⁻¹ bodyweight⁻¹. Mean microcirculatory blood flow (mean Flux) of the ileum was measured using direct laser-speckle-contrast-imaging. Receiver operating characteristic analysis was performed to determine the ability of pulse pressure variation to predict a decrease in microcirculation. A reduction of ≥ 10% mean Flux was considered a relevant decrease. After ischemia–reperfusion, volume-loading-steps led to a significant increase of cardiac output as well as mean arterial pressure, while pulse pressure variation and mean Flux were significantly reduced (Pairwise comparison ischemia/reperfusion-injury vs. volume loading step no. 4): cardiac output (l min⁻¹) 1.68 (1.02–2.35) versus 2.84 (2.15–3.53), p = 0.002, mean arterial pressure (mmHg) 29.89 (21.65–38.12) versus 52.34 (43.55–61.14), p < 0.001, pulse pressure variation (%) 24.84 (17.45–32.22) versus 9.59 (1.68–17.49), p = 0.004, mean Flux (p.u.) 414.95 (295.18–534.72) versus 327.21 (206.95–447.48), p = 0.006. Receiver operating characteristic analysis revealed an area under the curve of 0.88 (CI 95% 0.73–1.00; p value < 0.001) for pulse pressure variation for predicting a decrease of microcirculatory blood flow. The results of our study show that pulse pressure variation does have the potential to predict decreases of intestinal microcirculatory blood flow due to volume-load after ischemia/reperfusion-injury. This should encourage further translational research and might help to prevent microcirculatory impairment due to excessive fluid resuscitation and to guide fluid therapy in the future.

Postoperative outcomes based on crystalloid administration in pediatric patients with necrotizing enterocolitis undergoing laparotomy

Intravenous fluid prescription is an essential part of postoperative care and may play a causal role in postoperative complications. The objective of the present study was to evaluate the relationship between intraoperative fluid administration and postoperative outcomes in a large cohort of pediatric patients.This analysis included a retrospective review of 172 patients who underwent gastroenterological surgery from January 2012 to September 2018 at an academic tertiary care hospital. Patients were evaluated based on the median amount of corrected crystalloids and subsequently dichotomized as low (<25.89 mL/kg h) versus high (>25.89 mL/kg h). The primary outcome measure was the postoperative length of hospital stay (pLOS). Secondary outcome measures included the postoperative time to restore gastroenterological functions and postoperative complications.Patients who received larger amounts of crystalloids were more likely to have a lower intraoperative level of hemoglobin (P = .78) and an intraoperative blood transfusion (P = .27). There were trends toward lower incidence rates of hyperchloremic acidosis (P = .375) and metabolic acidosis (P = .54) in the high crystalloid administration cohort. The incidence of postoperative complications increased as the amount of administered fluid decreased (P = .046). The total length of hospital stay was shorter in patients who received high volumes of crystalloid fluid (19.5 [15.75-32.25] days) than in patients who received low volumes (22 [16-29.5] days, P = .283).Significant and multifaceted variability in crystalloid administration was noted among pediatric patients undergoing major surgery. High fluid administration was associated with favorable postoperative outcomes; these findings could be applied to improve patient safety and facilitate better quality of care.

Microcirculation-guided protection strategy in hemodynamic therapy

Microcirculatory shock is a condition defined by the presence of tissue hypoperfusion despite the normalization of systemic and regional blood flow. Currently, more evidence shows that intrinsic septic shock is microcirculatory shock, which results in septic shock that is difficult to resuscitate. At present, treatments are aimed at recovering macro-circulation functions and include fluid resuscitation, vasoactive drugs, positive inotropic drugs, de-obstruction, and even mechanical assistance to improve oxygen delivery. However, the application of these treatments to more accurately improve microcirculation or avoid further microcirculatory damage is more important in clinics. In this article, we discuss the need for microcirculation protection and microcirculation-guided protection strategies in hemodynamic therapies.

Hydroxyethyl starch for perioperative goal-directed fluid therapy in 2020: a narrative review

BACKGROUND

Perioperative fluid management - including the type, dose, and timing of administration -directly affects patient outcome after major surgery. The objective of fluid administration is to optimize intravascular fluid status to maintain adequate tissue perfusion. There is continuing controversy around the perioperative use of crystalloid versus colloid fluids. Unfortunately, the importance of fluid volume, which significantly influences the benefit-to-risk ratio of each chosen solution, has often been overlooked in this debate.

MAIN TEXT

The volume of fluid administered during the perioperative period can influence the incidence and severity of postoperative complications. Regrettably, there is still huge variability in fluid administration practices, both intra-and inter-individual, among clinicians. Goal-directed fluid therapy (GDFT), aimed at optimizing flow-related variables, has been demonstrated to have some clinical benefit and has been recommended by multiple professional societies. However, this approach has failed to achieve widespread adoption. A closed-loop fluid administration system designed to assist anesthesia providers in consistently applying GDFT strategies has recently been developed and tested. Such an approach may change the crystalloid versus colloid debate. Because colloid solutions have a more profound effect on intravascular volume and longer plasma persistence, their use in this more "controlled" context could be associated with a lower fluid balance, and potentially improved patient outcome. Additionally, most studies that have assessed the impact of a GDFT strategy on the outcome of high-risk surgical patients have used hydroxyethyl starch (HES) solutions in their protocols. Some of these studies have demonstrated beneficial effects, while none of them has reported severe complications.

CONCLUSIONS

The type and volume of fluid used for perioperative management need to be individualized according to the patient's hemodynamic status and clinical condition. The amount of fluid given should be guided by well-defined physiologic targets. Compliance with a predefined hemodynamic protocol may be optimized by using a computerized system. The type of fluid should also be individualized, as should any drug therapy, with careful consideration of timing and dose. It is our perspective that HES solutions remain a valid option for fluid therapy in the perioperative context because of their effects on blood volume and their reasonable benefit/risk profile.

Colloids and the Microcirculation

Colloid solutions have been advocated for use in treating hypovolemia due to their expected effect on improving intravascular retention compared with crystalloid solutions. Because the ultimate desired effect of fluid resuscitation is the improvement of microcirculatory perfusion and tissue oxygenation, it is of interest to study the effects of colloids and crystalloids at the level of microcirculation under conditions of shock and fluid resuscitation, and to explore the potential benefits of using colloids in terms of recruiting the microcirculation under conditions of hypovolemia. This article reviews the physiochemical properties of the various types of colloid solutions (eg, gelatin, dextrans, hydroxyethyl starches, and albumin) and the effects that they have under various conditions of hypovolemia in experimental and clinical scenarios.

Hydroxyethyl starches in equine medicine

OBJECTIVE

To review and discuss the use of hydroxyethyl starches (HES) in equine veterinary medicine, and to provide recommendations for its use.

DATA SOURCES

Veterinary and human peer-reviewed medical literature including scientific reviews, meta-analyses, and original research articles.

HUMAN DATA SYNTHESIS

Increasing evidences on adverse effects after HES use and decreasing support for beneficial effects with regards to volume expansion and colloid osmotic pressure (COP) support in critically ill subjects have led to a recent guideline to limit the use of HES in critically ill people.

EQUINE VETERINARY DATA SYNTHESIS

The rationale for HES use in horses is mainly extrapolated from human medicine, and very limited studies in horses are available. There is limited evidence suggesting a superiority of volume expansion effects of HES over crystalloids. The potential for HES to increase and maintain COP is well supported, but there is no evidence that maintaining or increasing plasma COP influences outcome, tissue edema formation, or rates of complications that potentially relate to edema formation. HES induce dose-dependent changes in coagulopathic parameters, but there is no evidence that HES causes clinical coagulopathies. Insufficient data are available on other adverse effects such as acute kidney injury, or mortality in horses. The use of HES should be restricted in septic patients, but may still have some use in cases of hemorrhagic shock resuscitation, hypoalbuminemia, or perioperative fluid replacement.

CONCLUSION

The evidence supporting the use of HES in horses is weak due to lack of species-specific investigations. Acknowledging species differences, the use of HES should be judicious, yet with some recognition of its benefits in particular cases. More research is necessary to improve knowledge on use of HES in horses and to establish better future recommendations.

Effect of goal-directed haemodynamic therapy in free flap reconstruction for head and neck cancer

BACKGROUND

In free flap reconstruction for head and neck cancer, achieving a haemodynamic target using excessive fluid infusion is associated with decreased flap survival rates and extended hospital stays. We hypothesized that goal-directed haemodynamic therapy would improve flap survival rates and shorten hospitalization periods.

METHODS

Patients scheduled for free flap reconstruction were randomly assigned to a goal-directed haemodynamic therapy group (n = 31) or a conventional haemodynamic therapy control group (n = 31). The control group received extra bolus fluid and ephedrine or norepinephrine to maintain a mean arterial pressure ≥ 65 mmHg. The goal-directed haemodynamic therapy group received a colloid solution as the extra bolus fluid to maintain a stroke volume variation < 12%; dobutamine, ephedrine, or norepinephrine was administered to maintain a cardiac index ≥ 2.5 l/min/m² and mean arterial pressure ≥ 65 mmHg. Enhanced recovery after surgery protocols were not used except for fluid therapy. An otolaryngologist blinded to group assignments assessed flap outcomes and classified them as 'survival,' 'at risk' or 'failure.'

RESULTS

The hospitalization period was not significantly different between the groups. The goal-directed haemodynamic therapy group had significantly shorter intensive care unit stays and a higher flap survival rate. The crystalloid volume was significantly lower in goal-directed haemodynamic therapy group. Reoperation rates, post-operative complications, and laboratory data including inflammatory markers were similar between the groups.

CONCLUSION

Compared to conventional haemodynamic therapy, goal-directed haemodynamic therapy does not reduce hospitalization periods; it may, however, reduce the length of intensive care unit stays and increase flap survival rates. Further studies including multi-centre trials with larger sample sizes are warranted.

Goal-directed fluid restriction using stroke volume variation and cardiac index during one-lung ventilation: a randomized controlled trial

Background

Goal-directed therapy confers a strong prognosis in patients undergoing major cardiac or noncardiac surgery. The present study investigated whether intraoperative goal-directed fluid restriction (GDFR) using stroke volume variation (SVV) and cardiac index could improve oxygenation and postoperative outcome in patients undergoing one-lung ventilation (OLV).

Methods

A Total of 168 patients scheduled for elective thoracoscopic lobectomy under OLV were randomized into the GDFR protocol (group G) or conventional fluid therapy groups (group C). Patients in group C underwent conventional fluid therapy based on mean arterial pressure (MAP), central venous pressure (CVP), and urine volume, whereas those in group G received GDFR protocol associated with the SVV from 10-13% and the cardiac index was controlled at a minimum of 2.5 L/min/m². The primary outcome variable was PaO₂/FiO₂. The secondary outcomes were other pulmonary variables and lung mechanics, inflammatory response, the incidence of postoperative pulmonary complications, and the length of hospital stay.

Results

During surgery, the PaO₂/FiO₂ ratio in group G was more than that of group C at 30 and 60 min after OLV, 10 min after re-expansion, and the end of the operation (259±29 vs. 314±34; 253±30 vs. 308±35; 341±34 vs. 394±39; 349±35 vs. 401±39, respectively, all P<0.001). Compared to conventional fluid therapy, GDFR protocol also significantly improved the hemodynamic and lung mechanics with the initiation of OLV. The incidence of postoperative pulmonary complications such as acute lung injury and pneumonia, and the length of hospital stay were decreased by GDFR protocol as compared to conventional fluid therapy (all P<0.05). However, there were no significant differences between groups with respect to the concentration of serum tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10).

Conclusions

The GDFR protocol based on SVV and cardiac index applied in patients undergoing OLV improves intraoperative pulmonary oxygenation. It can also reduce the postoperative complications and length of hospital stay. However, the GDFR strategy cannot reduce the local or systemic inflammation.

Trial registration

Chinese Clinical Trials Register ChiCTR-INR-16008288, Registered 20 April, 2016.

Ringer's Lactate Versus Normal Saline in Urgent Cesarean Delivery in a Resource-Limited Setting: A Pragmatic Clinical Trial

BACKGROUND

Crystalloids are used routinely for perioperative fluid management in cesarean delivery. Few studies have determined the crystalloid of choice in obstetric anesthesia. We compared the effects of Ringer's lactate (RL) versus 0.9% normal saline (NS) on maternal and neonatal blood pH and 24-hour postoperative morbidity in urgent cesarean delivery in a low-resource setting. Our hypothesis was that RL would result in 30% less acidosis than NS.

METHODS

This was a pragmatic prospective double-blind randomized controlled trial in the Mulago National Referral Hospital Labor Ward Theater from September 2011 to May 2012. Five hundred parturients were studied; 252 were randomly assigned to NS and 248 to RL groups. Preoperative and postoperative maternal venous blood gases and placental umbilical arterial cord blood gases were analyzed. The primary outcome was incidence of maternal acidosis, as defined by a postoperative drop in venous pH below 7.32 or reduction in base excess below -3 in a previously normal parturient. Maternal 24-hour postoperative morbidity, neonatal pH, and neonatal base excess were the main secondary outcomes. The study was registered in ClinicalTrials.gov as NCT01585740.

RESULTS

The overall incidence of maternal acidosis was 38% in NS and 29% in RL (relative risk, 1.29; 95% confidence interval, 1.01-1.66; P = .04). Thirty-two percent of parturients in NS experienced a drop in venous pH below 7.32 postoperatively, compared with 19% in RL (relative risk, 1.65; 95% confidence interval, 1.18-2.31; P = .003). The comparative drop in base excess postoperatively below -3 between the 2 groups was not statistically significant. There were no significant differences in the incidence of maternal 24-hour postoperative morbidity events and neonatal outcomes between the 2 groups.

CONCLUSIONS

NS may be a safe choice for intraoperative fluid therapy in urgent cesarean delivery as RL, albeit with an increased incidence of metabolic acidosis.

Impacts of albumin synergized with hydroxyethyl starch on early microvascular albumin leakage after major abdominal surgery in rabbits

PURPOSE

To investigate the impacts of albumin synergized with hydroxyethyl starch (HES) on early microvascular albumin leakage after major abdominal surgery in rabbits.

METHODS

Forty male Japanese rabbits were randomly divided into four groups: the control group, the saline group, the albumin group, and the Syn group (hydroxyethyl starch+albumin). The latter three groups were performed gastrectomy plus resection of pancreatic body and tail and splenectomy. The serum albumin concentration was detected before and 48h after surgery, and the conditions of mesenteric microvascular leakage in these 4 groups were observed under microscope 48 h after surgery to calculate the leakage rate.

RESULTS

Compared with the saline group, the albumin group and the Syn group exhibited significantly increased serum albumin concentrations 48h after surgery (P<0.05). The albumin leakage rate was the most obvious in the albumin group, followed by the saline group, while that in the Syn group was the minimal, and there existed significant differences among these groups (P<0.05) .

CONCLUSION

Simple administration of albumin in the early stage after major abdominal surgery could increase the albumin leakage, while the synergization of albumin and hydroxyethyl starch could reduce the albumin leakage.

The effect of pPolyHb on hemodynamic stability and mesenteric microcirculation in a rat model of hemorrhagic shock

The effects of polymerized porcine hemoglobin (pPolyHb) on hemodynamic stability and maintenance of mesenteric microvascular function were explored in a rat model of hemorrhagic shock (HS). Following controlled hemorrhage, rats were infused with equal volumes of either pPolyHb, hetastarch (HES), or red blood cell (RBC). The results showed that pPolyHb was superior to HES and RBC in restoring hemodynamic stability and reversing anaerobic metabolism. We observed a reduction in the diameter of mesenteric microvasculature after HS. Resuscitation with pPolyHb and RBC was able to restore the diameters of the venules and arterioles, whereas HES failed to restore the diameters during the observation period.

The influence of Ringer's lactate or HES 130/0.4 administration on the integrity of the small intestinal mucosa in a pig hemorrhagic shock model under general anesthesia

OBJECTIVE

To determine the effect of fluid resuscitation with 2 different physiological solutions, Ringer's lactate (RL) and hydroxyethyl starch (HES) 130/0.4, on histological lesions of the small intestinal mucosa in anesthetized pigs subjected to severe acute bleeding.

DESIGN

Prospective experimental study.

SETTING

University teaching hospital.

ANIMALS

Twenty-eight healthy Large White pigs, 3 months of age.

INTERVENTIONS

Pigs were subjected to severe acute bleeding (30 mL/kg) under total intravenous anesthesia with propofol and remifentanil. Pigs were randomly allocated to 3 groups: Group 1 (n = 11) received RL solution (25 mL/kg) after bleeding; Group 2 (n = 11) received HES 130/0.4 solution (20 mL/kg) after bleeding; and Group 3 (n = 6) volume replacement nor induced bleeding. Pigs were euthanized and the small intestine was harvested for histopathological analysis.

MEASUREMENTS AND MAIN RESULTS

The small intestine was histologically evaluated and the presence of the following lesions were characterized: edema, congestion, hyperemia, hemorrhage, inflammatory infiltration, cellular degeneration, necrosis, and epithelial detachment. Mucosal loss percentage (%ML) and crypt:interstitium ratio (C:I) were also assessed. In the duodenum, jejunum, and ileum, and the entire small intestine, the %ML was significantly higher in Group 1, than in Groups 2 and 3. Hyperemia in the small intestine was significantly higher in pigs resuscitated with HES 130/0.4 compared to pigs resuscitated with RL.

CONCLUSIONS AND CLINICAL RELEVANCE

In a setting of controlled hemorrhage, resuscitation with HES 130/0.4 was associated with a lower percentage of mucosal loss on the small intestine, compared with resuscitation with RL solution. Our study also suggests that the duodenum may be more sensitive to hypovolemia induced by severe hemorrhage.

Fluid replacement and respiratory function: comparison of whole blood with colloid and crystalloid: A randomised animal study

BACKGROUND

Fluid replacement with blood products, colloids and crystalloids is associated with morbidity and mortality. Despite this, the consequences of fluid administration on airway and respiratory tissue properties are not fully understood.

OBJECTIVE

Comparison of respiratory effects of fluid replacement with autologous blood (Group B), colloid (HES 6% 130/0.4, Group CO) or crystalloid solution (NaCl 0.9%, Group CR) after haemorrhage with separate assessments of airway resistance and respiratory tissue mechanics.

DESIGN

A randomised study.

SETTING

An experimental model of surgical haemorrhage and fluid replacement in rats.

PARTICIPANTS

Anaesthetised, ventilated rats randomly allocated into three groups (Group B: n = 8, Group CO: n = 8, Group CR: n = 9).

INTERVENTION

Animals were bled in six sequential steps, each manoeuvre targeting a loss of 5% of total blood volume. The blood loss was then replaced stepwise in a 1 : 1 ratio with one of the three fluids.

MAIN OUTCOME MEASURE

After each step, airway resistance (Raw), tissue damping and elastance (H) were determined by forced oscillations. Oedema indices from lung weights and histology were also measured.

RESULTS

Raw (mean ± SD) decreased in all groups following blood loss (-20.3 ± 9.5% vs. baseline, P < 0.05), and remained low following blood replacement (-21.7 ± 14.5% vs. baseline, P < 0.05), but was normalised by colloid (5.5 ± 10.7%, NS). Crystalloid administration exhibited an intermediate reversal effect (-8.4 ± 14.7%, NS). Tissue viscoelasticity increased following both blood loss and replacement, with no evidence of a significant difference in H between Groups CO and CR. More severe oedema was observed in Groups CR and CO than in Group B (P < 0.05), with no difference between the colloid and crystalloid solutions.

CONCLUSION

This model, which mimics surgical haemorrhage, yields no evidence of a difference between colloids and crystalloids with regard to the pulmonary consequences of blood volume restoration. Functional changes in the lung should not be a key concern when choosing fluid replacement therapy with these solutions.

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.

Rapid Infusion of Hydroxyethyl Starch 70/0.5 but not Acetate Ringer’s Solution Decreases the Plasma Concentration of Propofol during Target-controlled Infusion

Background

Rapid fluid infusion resulting in increased hepatic blood flow may decrease the propofol plasma concentration (Cp) because propofol is a high hepatic extraction drug. The authors investigated the effects of rapid colloid and crystalloid infusions on the propofol Cp during target-controlled infusion.

Methods

Thirty-six patients were randomly assigned to 1 of 3 interventions (12 patients per group). At least 30 min after the start of propofol infusion, patients received either a 6% hydroxyethyl starch (HES) solution at 24 ml·kg−1·h−1 or acetated Ringer’s solution at 24 or 2 ml·kg−1·h−1 during the first 20 min. In all groups, acetated Ringer’s solution was infused at 2 ml·kg−1·h−1 during the next 20 min. The propofol Cp was measured every 2.5 min as the primary outcome. Cardiac output, blood volume, and indocyanine green disappearance rate were determined using a pulse dye densitogram analyzer before and after the start of fluid administration. Effective hepatic blood flow was calculated as the blood volume multiplied by the indocyanine green disappearance rate.

Results

The rapid HES infusion significantly decreased the propofol Cp by 22 to 37%, compared to the Cp at 0 min, whereas the rapid or maintenance infusion of acetate Ringer’s solution did not decrease the propofol Cp. Rapid HES infusion, but not acetate Ringer’s solution infusion, increased the effective hepatic blood flow.

Conclusions

Rapid HES infusion increased the effective hepatic blood flow, resulting in a decreased propofol Cp during target-controlled infusion. Rapid HES infusion should be used cautiously as it may decrease the depth of anesthesia.

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.

Controversies in the use of hydroxyethyl starch solutions in small animal emergency and critical care

OBJECTIVES

To (1) review the development and medical applications of hydroxyethyl starch (HES) solutions with particular emphasis on its physiochemical properties; (2) critically appraise the available evidence in human and veterinary medicine, and (3) evaluate the potential risks and benefits associated with their use in critically ill small animals.

DATA SOURCES

Human and veterinary original research articles, scientific reviews, and textbook sources from 1950 to the present.

HUMAN DATA SYNTHESIS

HES solutions have been used extensively in people for over 30 years and ever since its introduction there has been a great deal of debate over its safety and efficacy. Recently, results of seminal trials and meta-analyses showing increased risks related to kidney dysfunction and mortality in septic and critically ill patients, have led to the restriction of HES use in these patient populations by European regulatory authorities. Although the initial ban on the use of HES in Europe has been eased, proof regarding the benefits and safety profile of HES in trauma and surgical patient populations has been requested by these same European regulatory authorities.

VETERINARY DATA SYNTHESIS

The veterinary literature is limited mostly to experimental studies and clinical investigations with small populations of patients with short-term end points and there is insufficient evidence to generate recommendations.

CONCLUSIONS

Currently, there are no consensus recommendations regarding the use of HES in veterinary medicine. Veterinarians and institutions affected by the HES restrictions have had to critically reassess the risks and benefits related to HES usage based on the available information and sometimes adapt their procedures and policies based on their reassessment. Meanwhile, large, prospective, randomized veterinary studies evaluating HES use are needed to achieve relevant levels of evidence to enable formulation of specific veterinary guidelines.

Fluid loading in abdominal surgery - saline versus hydroxyethyl starch (FLASH Trial): study protocol for a randomized controlled trial

Background

Inappropriate fluid therapy during surgery is associated with significant morbidity and mortality. Few studies have examined the effects of particular types of fluids (crystalloid or colloid solutions) in surgical patients, especially with the goal of hemodynamic optimization. Isotonic saline is the most commonly used fluid worldwide but may be associated with potential nephrotoxicity. Hydroxyethyl starch (HES) solutions are widely used in surgical patients as a component of goal-directed fluid optimization strategies, but several large multicenter studies have suggested increased rates of acute kidney injury and adverse events with the use of HES in ICU patients. Despite what may be inferred from physiological studies, the benefit and harm of 0.9 % saline and HES during hemodynamic therapy have not been clearly established in surgical patients.

Methods/Design

The FLASH trial is an investigator-initiated, prospective, multicenter, randomized, double-blinded, two-arm trial, randomizing 826 patients with moderate-to-high risk of postoperative complications to receive 6 % HES 130/0.4 or 0.9 % saline during individualized goal-directed fluid optimization. The primary outcome measure is a composite of death or major postoperative complications within 14 days following surgery.

The sample size will allow the detection of a 10 % absolute between-group difference in the primary outcome measure with a type 1 error rate of 5 % and power of 95 %, assuming a 5 % mortality rate and 20 % morbidity (thus 25 % for the composite endpoint).

Discussion

The FLASH trial may provide important data on the efficacy and safety of commonly used fluid solutions and could have a significant impact on future treatment of surgical patients.

Trial registration

ClinicalTrials.gov Identifier: NCT02502773. Registered 16 June 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-1085-3) contains supplementary material, which is available to authorized users.

The brain relaxation and cerebral metabolism in stroke volume variation-directed fluid therapy during supratentorial tumors resection: crystalloid solution versus colloid solution

BACKGROUND

Compared with goal-directed crystalloid therapy, goal-directed colloid therapy during high-risk surgery may improve postoperative outcome. Whether intraoperative fluid therapy based on goal-directed protocol with different types of fluid has distinctive effects on brain relaxation and cerebral metabolism during craniotomy remains unclear.

METHODS

Forty patients with supratentorial brain tumors undergoing craniotomy were randomly assigned to either a Ringer's Lactate-based goal-directed group (LR group, n=20) or a 6% hydroxyethyl starch-based goal-directed group (HES group, n=20). The goal was achieved by maintaining a target stroke volume variation (SVV<13%) by volume loading with LR or HES throughout the procedure. The primary outcome is brain relaxation scales, an indirect evaluation of ICP; secondary endpoints include cerebral metabolism variables (jugular venous oxygen saturation [SjvO(2)], arterial-jugular venous differences in oxygen [CajvO(2)], glucose [A-JvGD], lactate [A-JvLD], and cerebral extraction ratio for oxygen [CERO(2)]) and fluid volumes.

RESULTS

There is no significant difference between the LR and HES groups on brain relaxation scales (P=0.845), or measures of cerebral oxygenation and metabolism. Intragroup comparisons showed that CERO(2) increased by 14.3% (P=0.009, LR group) and 13.2% (P=0.032, HES group), respectively, and SjvO(2) was decreased by 8.8% (P=0.016, LR group) and 8.1% (P=0.026, HES group), respectively, after tumor removal, compared with baseline. During surgery, the LR group (3070±1138 mL) received more fluid than the HES group (2041±758 mL, P=0.002).

CONCLUSIONS

In patients undergoing supratentorial tumor resection, goal-directed HES therapy was not superior to goal-directed LR therapy for brain relaxation or cerebral metabolism, although less fluid was needed to maintain the target SVV in the HES-based group than in the LR-based group.

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.

A randomized trial of goal directed vs. standard fluid therapy in cytoreductive surgery with hyperthermic intraperitoneal chemotherapy

The use of adequate fluid therapy during cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) remains controversial. The aim of the study was to assess whether the use of fluid therapy protocol combined with goal-directed therapy (GDT) is associated with a significant change in morbidity, length of hospital stay, and mortality compared to standard fluid therapy. Patients American Society of Anesthesiologists (ASA) II-III undergoing CRS and HIPEC were randomized into two groups. The GDT group (N = 38) received fluid therapy according to a protocol guided by monitored hemodynamic parameters. The control group (N = 42) received standard fluid therapy. We evaluated incidence of major complications, total length of hospital stay, total amount of fluids administered, and mortality rate. The incidence of major abdominal complications was 10.5% in GDT group and 38.1% in the control group (P = 0.005). The median duration of hospitalization was 19 days in GDT group and 29 days in the control group (P < 0.0001). The mortality rate was zero in GDT group vs. 9.5% in the control group (P = 0.12). GDT group received a significantly (P < 0.0001) lower amount of fluid (5812 ± 1244 ml) than the control group (8269 ± 1452 ml), with a significantly (P < 0.0001) lower volume of crystalloids (3884 ± 1003 vs. 68,528 ± 1413 ml). In CRS and HIPEC, the use of a GDT improves outcome in terms of incidence of major abdominal and systemic postoperative complications and length of hospital stay, compared to standard fluid therapy protocol.

Meta-analysis of the effect of goal-directed therapy on bowel function after abdominal surgery

Background

Intraoperative goal-directed therapy (GDT) was introduced to titrate intravenous fluids, with or without inotropic drugs, based on objective measures of hypovolaemia and cardiac output measurements to improve organ perfusion. This meta-analysis aimed to determine the effect of GDT on the recovery of bowel function after abdominal surgery.

Methods

MEDLINE, Embase, the Cochrane Library and PubMed databases were searched for randomized clinical trials and cohort studies, from January 1989 to June 2013, that compared patients who did, or did not, receive intraoperative GDT, and reported outcomes on the recovery of bowel function. Time to first flatus and first bowel motion, time to tolerate oral diet, postoperative nausea and vomiting, and primary postoperative ileus were included.

Results

Thirteen trials with 1399 patients were included in the analysis. GDT shortened the time to the first bowel motion (weighted mean difference (WMD −0·67, 95 per cent c.i. −1·23 to −0·11; P = 0·020) and time to tolerate oral intake (WMD −0·95, −1·81 to −0·10; P = 0·030), and reduced postoperative nausea and vomiting (risk difference −0·15, −0·26 to −0·03; P = 0·010). When only high-quality studies were included, GDT reduced only the time to tolerate oral intake (WMD −1·18, −2·03 to −0·33; P = 0·006). GDT was more effective outside enhanced recovery programmes and in patients undergoing colorectal surgery.

Conclusion

GDT facilitated the recovery of bowel function, particularly in patients not treated within enhanced recovery programmes and in those undergoing colorectal operations.

Stroke volume-directed administration of hydroxyethyl starch (HES 130/0.4) and Ringer’s acetate in prone position during neurosurgery: a randomized controlled trial

PURPOSE

General anesthesia in the prone position is associated with hypotension. We studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer’s acetate (RAC) in neurosurgical patients operated on in a prone position to determine the volumes required for stable hemodynamics and possible coagulatory effects.

METHODS

Thirty elective neurosurgical patients received either HES (n = 15) or RAC (n = 15). Before positioning, SV measured by arterial pressure waveform analysis was maximized by fluid boluses until SV did not increase more than 10 %. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups. Thromboelastometry assessed coagulation. Mann–Whitney U test, Wilcoxon signed-rank test, ANOVA on ranks, and a linear mixed model were applied.

RESULTS

Comparable hemodynamics were achieved with the mean cumulative (SD) boluses of HES or RAC 240 (51) or 267 (62) ml (P = 0.207) before positioning, 340 (124) or 453 (160) ml (P = 0.039) 30 min after positioning, and 440 (229) or 653 (368) ml at the end of surgery (P = 0.067). The mean dose of basal RAC infusion was 813 (235) and 868 (354) ml (P = 0.620) in the HES and RAC group, respectively. Formation and maximum strength of the fibrin clot were decreased in the HES group. Intraoperative blood loss was comparable between groups (P = 0.861).

CONCLUSION

The amount of RAC needed in the prone position was 25 % greater. The cumulative dose of 440 ml HES induced a slight disturbance in fibrin formation and clot strength. We suggest cautious administration of HES during neurosurgery.

Microcirculatory effects of intravenous fluid administration in anesthetized dogs undergoing elective ovariohysterectomy

OBJECTIVE

To assess the microcirculatory effects of IV fluid administration in healthy anesthetized dogs undergoing elective ovariohysterectomy.

ANIMALS

49 client-owned dogs.

PROCEDURES

Dogs were sedated, and anesthesia was induced with propofol and diazepam and maintained with isoflurane in oxygen. Dogs received lactated Ringer's solution (LRS) IV at rates of 0, 10, or 20 mL/kg/h. Videomicroscopy was used to assess and record effects of LRS administration on microcirculation in the buccal mucosa. Measurements of microcirculatory (total vessel density, proportion of perfused vessels, microcirculatory flow index, and perfused vessel density by vessel size [< 20 μm, ≥ 20 μm, and all diameters]) and other physiologic variables (heart rate, Doppler-measured blood pressure, oxygen saturation as measured by pulse oximetry, capillary refill time, and body temperature) were compared among groups at baseline (immediately after anesthetic induction), 30 and 60 minutes afterward, and overall.

RESULTS

Neither the proportion of perfused vessels nor microcirculatory flow index varied among treatment groups at any time point, regardless of vessel size. For vessels < 20 μm in diameter and for all vessels combined, total and perfused vessel density were similar among groups. For vessels ≥ 20 μm in diameter, total vessel density was significantly greater in the 20 mL/kg/h group than in other groups, and perfused vessel density was significantly greater in the 20 mL/kg/h group than in the 0 mL/kg/h group, when all time points were considered. Other physiologic variables were similar among groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Total and perfused vessel density of vessels ≥ 20 μm in diameter (mostly venules) were greatest in dogs that received 20 mL of LRS/kg/h. Further research is required to evaluate clinical importance of these findings.

The influence of goal-directed fluid therapy on the prognosis of elderly patients with hypertension and gastric cancer surgery

Purpose

We aimed to investigate the influence of perioperative goal-directed fluid therapy (GDFT) on the prognosis of elderly patients with gastric cancer and hypertension.

Methods

Sixty elderly patients (>60 years old) with primary hypertension who received gastric cancer radical surgery and who were American Society of Anesthesiologists (ASA) class II or III were enrolled in the current study. Selected patients were divided randomly into two arms, comprising a conventional intraoperative fluid management arm (arm C, n=30) and a GDFT arm (arm G, n=30). Patients in arm C were infused with crystalloids or colloids according to the methods of Miller’s Anesthesia (6th edition), while those in arm G were infused with 200 mL hydroxyethyl starch over 15 minutes under the FloTrac/Vigileo monitoring system, with stroke volume variation between 8% and 13%. Hemodynamics and tissue perfusion laboratory indicators in patients were recorded continuously from 30 minutes before the operation to 24 hours after the operation.

Results

Compared with arm C, the average intraoperative intravenous infusion quantity in arm G was significantly reduced (2,732±488 mL versus 3,135±346 mL, P<0.05), whereas average colloid fluid volume was significantly increased (1,235±360 mL versus 760±280 mL, P<0.05). In addition, there were more patients exhibiting intraoperatively and postoperatively stable hemodynamics and less patients with low blood pressure in arm G. Postoperative complications were less frequent, and the time of postoperative hospital stay shorter, in arm G. No significant differences were observed in mortality between the two arms.

Conclusion

Our research showed that GDFT stabilized perioperative hemodynamics and reduced the occurrence of postoperative complications in elderly patients who underwent gastric cancer surgery.

Cardiac complications associated with goal-directed therapy in high-risk surgical patients: a meta-analysis

Patients with limited cardiopulmonary reserve are at risk of mortality and morbidity after major surgery. Augmentation of oxygen delivery index (DO2I) with i.v. fluids and inotropes (goal-directed therapy, GDT) has been shown to reduce postoperative mortality and morbidity in high-risk patients. Concerns regarding cardiac complications associated with fluid challenges and inotropes may prevent clinicians from performing GDT in patients who need it most. We hypothesized that GDT is not associated with an increased risk of cardiac complications in high-risk, non-cardiac surgical patients. We performed a systematic search of Medline, Embase, and CENTRAL databases for randomized controlled trials (RCTs) of GDT in high-risk surgical patients. Studies including cardiac surgery, trauma, and paediatric surgery were excluded. We reviewed the rates of all cardiac complications, arrhythmias, myocardial ischaemia, and acute pulmonary oedema. Meta-analyses were performed using RevMan software. Data are presented as odds ratios (ORs), [95% confidence intervals (CIs)], and P-values. Twenty-two RCTs including 2129 patients reported cardiac complications. GDT was associated with a reduction in total cardiovascular (CVS) complications [OR=0.54, (0.38-0.76), P=0.0005] and arrhythmias [OR=0.54, (0.35-0.85), P=0.007]. GDT was not associated with an increase in acute pulmonary oedema [OR=0.69, (0.43-1.10), P=0.12] or myocardial ischaemia [OR=0.70, (0.38-1.28), P=0.25]. Subgroup analysis revealed the benefit is most pronounced in patients receiving fluid and inotrope therapy to achieve a supranormal DO2I, with the use of minimally invasive cardiac output monitors. Treatment of high-risk surgical patients GDT is not associated with an increased risk of cardiac complications; GDT with fluids and inotropes to optimize DO2I during early GDT reduces postoperative CVS complications.

Dehydration, hemodynamics and fluid volume optimization after induction of general anesthesia

OBJECTIVES

Fluid volume optimization guided by stroke volume measurements reduces complications of colorectal and high-risk surgeries. We studied whether dehydration or a strong hemodynamic response to general anesthesia increases the probability of fluid responsiveness before surgery begins.

METHODS

Cardiac output, stroke volume, central venous pressure and arterial pressures were measured in 111 patients before general anesthesia (baseline), after induction and stepwise after three bolus infusions of 3 ml/kg of 6% hydroxyethyl starch 130/0.4 (n=86) or Ringer's lactate (n=25). A subgroup of 30 patients who received starch were preloaded with 500 ml of Ringer's lactate. Blood volume changes were estimated from the hemoglobin concentration and dehydration was estimated from evidence of renal water conservation in urine samples.

RESULTS

Induction of anesthesia decreased the stroke volume to 62% of baseline (mean); administration of fluids restored this value to 84% (starch) and 68% (Ringer's). The optimized stroke volume index was clustered around 35-40 ml/m2/beat. Additional fluid boluses increased the stroke volume by ≥10% (a sign of fluid responsiveness) in patients with dehydration, as suggested by a low cardiac index and central venous pressure at baseline and by high urinary osmolality, creatinine concentration and specific gravity. Preloading and the hemodynamic response to induction did not correlate with fluid responsiveness. The blood volume expanded 2.3 (starch) and 1.8 (Ringer's) times over the infused volume.

CONCLUSIONS

Fluid volume optimization did not induce a hyperkinetic state but ameliorated the decrease in stroke volume caused by anesthesia. Dehydration, but not the hemodynamic response to the induction, was correlated with fluid responsiveness.

The effect of fluid overload in the presence of an epidural on the strength of colonic anastomoses

BACKGROUND

Despite the beneficial effects of epidurals in intra-abdominal surgery, the incidence of anastomotic leak remains controversial when used. Moreover, studies have also shown that fluid overload may be deleterious to anastomoses. The purpose of this paper is to evaluate the effects of varying intraoperative fluid protocols, in the presence of an epidural, on the burst pressure strength of colonic anastomoses.

METHODS

An epidural was installed in 18 rabbits, divided into three groups. Group 1 received 30 mL/kg/h Ringer's lactate, Group 2 received 100 mL/kg/h Ringer's lactate, and Group 3 received 30 mL/kg/h Pentaspan. Two colo-colonic anastomoses were performed per rabbit. On postoperative day 7 the anastomoses were resected and their burst pressures measured as a surrogate for anastomotic leak.

RESULTS

When comparing the average burst pressures of all three groups, there was a significant difference (P = 0.04). The anastomoses in the 100 mL/kg/h Ringer's lactate group were shown to be the weakest, with 64% of the anastomoses having burst under 120 mm Hg. The rabbits hydrated with Pentaspan had the highest strength, with no anastomoses bursting under 120 mm Hg. This translated into significant burst pressure differences (P = 0.02) between Group 2 and Group 3.

CONCLUSION

These results suggest that fluid overload with a crystalloid, in the presence of an epidural, may be deleterious to the healing of colonic anastomoses, creating a higher risk of anastomotic leak. Intraoperative resuscitation should thus focus on goal-directed euvolemia with appropriate amounts of colloids and/or crystalloids to prevent the risk of weakening anastomoses, especially in patients with epidurals.

Clinical review: Goal-directed therapy-what is the evidence in surgical patients? The effect on different risk groups

Patients with limited cardiac reserve are less likely to survive and develop more complications following major surgery. By augmenting oxygen delivery index (DO₂I) with a combination of intravenous fluids and inotropes (goal directed therapy (GDT)), postoperative mortality and morbidity of high-risk patients may be reduced. However, although most studies suggest that GDT may improve outcome in high-risk surgical patients, it is still not widely practiced. We set out to test the hypothesis that GDT results in greatest benefit in terms of mortality and morbidity in patients with the highest risk of mortality and have undertaken a systematic review of the current literature to see if this is correct. We performed a systematic search of Medline, Embase and CENTRAL databases for randomized controlled trials (RCTs) and reviews of GDT in surgical patients. To minimize heterogeneity we excluded studies involving cardiac, trauma, and paediatric surgery. Extremely high risk, high risk and intermediate risks of mortality were defined as >20%, 5 to 20% and <5% mortality rates in the control arms of the trials, respectively. Meta analyses were performed and Forest plots drawn using RevMan software. Data are presented as odd ratios (OR; 95% confidence intervals (CI), and P-values). A total of 32 RCTs including 2,808 patients were reviewed. All studies reported mortality. Five studies (including 300 patients) were excluded from assessment of complication rates as the number of patients with complications was not reported. The mortality benefit of GDT was confined to the extremely high-risk group (OR = 0.20, 95% CI 0.09 to 0.41; P < 0.0001). Complication rates were reduced in all subgroups (OR = 0.45, 95% CI 0.34 to 0.60; P < 0.00001). The morbidity benefit was greatest amongst patients in the extremely high-risk subgroup (OR = 0.27, 95% CI 0.15 to 0.51; P < 0.0001), followed by the intermediate risk subgroup (OR = 0.43, 95% CI 0.27 to 0.67; P = 0.0002), and the high-risk subgroup (OR 0.56, 95% CI 0.36 to 0.89; P = 0.01). Despite heterogeneity in trial quality and design, we found GDT to be beneficial in all high-risk patients undergoing major surgery. The mortality benefit of GDT was confined to the subgroup of patients at extremely high risk of death. The reduction of complication rates was seen across all subgroups of GDT patients.

The role of transesophageal echocardiography in the intraoperative period

The goal of hemodynamic monitoring and management during major surgery is to guarantee adequate organ perfusion, a major prerequisite for adequate tissue oxygenation and thus, end-organ function. Further, hemodynamic monitoring should serve to prevent, detect, and to effectively guide treatment of potentially life-threatening hemodynamic events, such as severe hypovolemia due to hemorrhage, or cardiac failure. The ideal monitoring device does not exist, but some conditions must be met: it should be easy and operator-independently to use; it should provide adequate, reproducible information in real time. In this review we discuss in particular the role of intraoperative use of transesophageal echocardiography (TOE). Although TOE has gained special relevance in cardiac surgery, its role in major non cardiac surgery is still to be determined. We particularly focus on its ability to provide measurements of cardiac output (CO), and its role to guide fluid therapy. Within the last decade, concepts oriented on optimizing stroke volume and cardiac output mainly by fluid administration and guided by continuous monitoring of cardiac output or so called functional parameters of cardiac preload gained particular attention. Although they are potentially linked to an increased amount of fluid infusion, recent data give evidence that such pre-emptive concepts of hemodynamic optimization result in a decrease in morbidity and mortality. As TOE allows a real time direct visualization of cardiac structures, other potentially important advantages of its use also outside the cardiac surgery operation room can be postulated, namely the ability to evaluate the anatomical and functional integrity of the left and the right heart chambers. Finally, a practical approach to TOE monitoring is presented, based on a local experience.

Anesthesia and perioperative management of colorectal surgical patients - specific issues (part 2)

Colorectal surgery carries significant morbidity and mortality, which is associated with an enormous use of healthcare resources. Patients with pre-existing morbidities, and those undergoing emergency colorectal surgery due to complications such as perforation, obstruction, or ischemia / infarction are at an increased risk for adverse outcomes. Fluid therapy in emergency colorectal surgical patients can be challenging as hypovolemic and septic shock may coexist. Abdominal sepsis is a serious complication and may be diagnosed during pre-, intra-, or postoperative periods. Early suspicion and recognition of medical and / or surgical complications are essential. The critical care management of complicated colorectal surgical patients require collaborative and multidisciplinary efforts.