Effects of colloid-based (hydroxyethylstarch 6% 130/0.42, gelafundin 4%) and crystalloid-based volume regimes in cardiac surgery: a retrospective analysis

BACKGROUND

The restriction of hydroxyethylstarch (HES) necessitated changes in volume management in cardiac surgery, increasing the use of gelatin (GELA) and crystalloid (CRYS) mono strategies.

METHODS

This retrospective study evaluated the effects of changed volume replacement management to a GELA or CRYS mono therapy on mortality, acute kidney injury (AKI), blood loss, and transfusion in cardiac surgery patients with at least one coronary artery bypass grafting (CABG) at a university hospital. Three groups (HES n=938, GELA n=397, CRYS n=205) were derived from 1,540 patients with complete data sets. Data were analyzed by multiple regression models.

RESULTS

Patients had similar risk profiles, comorbidities, and preoperative routine diagnostics prior to surgery. No difference was observed in mortality and AKI. HES treated patients showed highest blood loss, followed by GELA while CRYS patients had the lowest (P<0.0001). Patients in the HES group had highest transfusion of packed red blood cells (PRBCs) and platelet concentrates (PCs), followed by GELA, whereas CRYS had the lowest (P<0.0001). Fresh frozen plasma (FFP) transfusion, administration of fibrinogen, and prothrombin complex concentrates (PCCs) were highest in HES group. CRYS showed the shortest time of mechanical ventilation (P<0.0001) and left the intensive care unit (ICU) significantly earlier (P<0.0001). Multivariable regression analysis found that colloid volume significantly predicted hospital mortality and renal replacement therapy (RRT), but not AKI.

CONCLUSIONS

Administration of crystalloids without any colloid showed no differences in mortality or AKI, but less blood loss and transfusion. Colloids should be considered critically and further studies should investigate effects of GELA in cardiac surgery.

Safety and efficacy of tetrastarches in surgery and trauma: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Hydroxyethyl starch (HES) 130 is a frequently used fluid to replace intravascular losses during surgery or trauma. In the past years, several trials performed in critically ill patients have raised questions regarding the safety of this product. Our aim in this meta-analysis was to evaluate the safety and efficacy of 6% HES during surgery and in trauma.

METHODS

This systematic review and meta-analysis was registered at PROSPERO (CRD42018100379). We included 85 fully published articles from 1980 to June 2018 according to the protocol and three additional recent articles up to June 2020 in English, French, German, and Spanish reporting on prospective, randomised, and controlled clinical trials applying volume therapy with HES 130/0.4 or HES 130/0.42, including combinations with crystalloids, to patients undergoing surgery. Comparators were albumin, gelatin, and crystalloids only. A meta-analysis could not be performed for the two trauma studies as there was only one study that reported data on endpoints of interest.

RESULTS

Surgical patients treated with HES had lower postoperative serum creatinine (P<0.001) and showed no differences in renal dysfunction, renal failure, or renal replacement therapy. Although there was practically no further difference in the colloids albumin or gelatin, the use of HES improved haemodynamic stability, reduced need for vasopressors (P<0.001), and decreased length of hospital stay (P<0.001) compared with the use of crystalloids alone.

CONCLUSIONS

HES was shown to be safe and efficacious in the perioperative setting. Results of the present meta-analysis suggest that when used with adequate indication, a combination of intravenous fluid therapy with crystalloids and volume replacement with HES as colloid has clinically beneficial effects over using crystalloids only.

Comparison of the Effects of Ringer's Lactate and 6% Hydroxyethyl Starch 130/0.4 on Blood Loss and Need for Blood Transfusion After Off-Pump Coronary Artery Bypass Graft Cardiac Surgery

Background Infusion of crystalloids fluid replacement therapy tends to cause a greater expansion of intravascular volume. However, colloids can affect blood coagulation leading to greater blood loss and transfusion requirements. This study compared the intraoperative and postoperative blood loss with Ringer's lactate (RL) versus 6% hydroxyethyl starch (HES) 130/0.4 as infusion fluid during cardiac surgery. Methods Eighty adult male and female patients undergoing elective cardiac surgery were randomly assigned to receive either RL or 6% HES 130/0.4 20 ml/kg during off-pump coronary artery bypass graft (OP-CABG) surgery. Intraoperative blood loss and 24 hours postoperative chest tube drainage were the primary outcomes. Simultaneously, blood transfusions, thromboelastometry variables, total fluid requirement, renal function, and intensive care unit (ICU) stay were assessed. Results The intraoperative blood loss was similar (p > 0.05) with HES (716 ml) and RL (658 ml). Postoperative chest tube drainage was higher (p < 0.05) with HES (513 ml) as against RL (449 ml). The total fluid requirement was higher in the RL group. Alteration of thromboelastometry variables, renal function, and ICU stay was comparable between the two groups. Postoperative chest tube drainage was less with the use of RL during cardiac surgery. A lesser total fluid requirement in the HES group did not lead to any improvement in renal function and the length of ICU stay. Conclusions Crystalloids (RL) provide similar outcomes to HES and can be used as substitutes to colloids during cardiac surgery. However, further large-scale multicenter studies with varied indications can be suggested to substantiate the equivalence of crystalloids to colloids in perioperative management.

Intravenous Fluid Administration and the Coagulation System

Intravenous fluid administration in veterinary patients can alter coagulation function by several mechanisms. Both crystalloid and colloid fluids cause hemodilution, reducing platelet count and plasma coagulation protein concentrations. Hemodilution is associated with a hypercoagulable effect at low dilutions and a hypocoagulable effect at higher dilutions. Composition of crystalloid fluids likely has a minor effect, primarily dependent on fluid ion composition. Hypertonic crystalloids may also cause hypocoagulability. Colloids, both synthetic and natural, can cause hypocoagulability by several mechanisms beyond the effects of hemodilution. These include impaired platelet function, decreased plasma coagulation factor activity, impaired fibrin formation and crosslinking, and accelerated fibrinolysis. The vast majority of the veterinary literature investigates the hypocoagulable effects of hydroxyethyl starch-containing fluids using in vitro, experimental, and clinical studies. However, results are inconsistent, likely due to the varying doses and physicochemical properties of the specific fluid products across studies. In addition, some evidence exists for hypocoagulable effects of gelatin and albumin solutions. There is also evidence that these colloids increase the risk of clinical bleeding in people. Limitations of the veterinary evidence for the hypocoagulable effects of colloid fluids include a predominance of in vitro studies and in vivo studies using healthy subjects, which exclude the interaction of the effects of illness. Therefore, clinical relevance of these effects, especially for low-molecular-weight hydroxyethyl starch, is unknown. Firm recommendations about the most appropriate fluid to use in clinical scenarios cannot be made, although it is prudent to limit the dose of synthetic colloid in at-risk patients. Clinicians should closely monitor relevant coagulation assays and for evidence of hemorrhage in at-risk patients receiving any type of fluid therapy, especially in large volumes.

Safety of gelatin solutions for the priming of cardiopulmonary bypass in cardiac surgery: a systematic review and meta-analysis

This systematic review and meta-analysis was conducted to evaluate the safety of gelatin versus hydroxyethyl starches (HES) and crystalloids when used for cardiopulmonary bypass (CPB)-priming in cardiac surgery. MEDLINE (Pubmed), Embase and CENTRAL were searched. We included only randomized, controlled trials comparing CPB-priming with gelatin with either crystalloids or HES-solutions of the newest generation. The primary endpoint was the blood loss during the first 24 hours. Secondary outcomes included perioperative transfusion requirements, postoperative kidney function, postoperative ventilation times and length of stay on the intensive care unit. Sixteen studies were identified, of which only ten met the inclusion criteria, representing a total of 824 adult patients: 4 studies compared gelatin with crystalloid, and 6 studies gelatin with HES priming. Only 2 of the studies comparing HES and gelatin reported postoperative blood loss after 24 hours. No significant difference in postoperative blood loss was found when results of both studies were pooled (SMD -0.12; 95% CI: -0.49, 0.25; P=0.52). Likewise, the pooled results of 3 studies comparing gelatin and crystalloids as a priming solution could not demonstrate significant differences in postoperative bleeding after 24 hours (SMD -0.07; 95% CI: -0.40, 0.26; P=0.68). No differences regarding any of the secondary outcomes could be identified. This systematic review suggests gelatins to have a safety profile which is non-inferior to modern-generation tetrastarches or crystalloids. However, the grade of evidence is rated low owing to the poor methodological quality of the included studies, due to inconsistent outcome reporting and lack of uniform endpoint definitions.

Fluids and coagulation

PURPOSE OF REVIEW

Infusion therapy is essential in intravascular hypovolaemia and extravascular fluid deficits. Crystalloidal fluids and colloidal volume replacement affect blood coagulation when infused intravenously. The question remains if this side-effect of infusion therapy is clinically relevant in patients with and without bleeding manifestations, and if fluid-induced coagulopathy is a risk factor for anaemia, blood transfusion, and mortality, and a driver for resource use and costs.

RECENT FINDINGS

Pathomechanisms of dilutional coagulopathy and evidence for its clinical relevance in perioperative and critically ill patients are reviewed. Furthermore, the article discusses medicolegal aspects.

SUMMARY

The dose-dependent risk of dilutional coagulopathy differs between colloids (dextran > hetastarch > pentastarch > tetrastarch, gelatins > albumin). Risk awareness includes monitoring for early signs of side-effects. With rotational thromboelastometry/thrombelastography, the deterioration not only in clot strength but also in clot formation and in platelet interaction can be assessed. Fibrinogen concentrate administration may be considered in severe bleeding as well as relevant dilutional coagulopathy. Targeted doses of gelatins and tetrastarches seem to have no proven adverse effect on anaemia and allogeneic blood transfusions. Further studies are needed.

Hydroxyethyl starch versus other fluids for non-septic patients in the intensive care unit: a meta-analysis of randomized controlled trials

INTRODUCTION

Use of hydroxyethyl starch (HES) in septic patients is reported to increase the mortality and incidence of renal replacement therapy (RRT). However, whether or not use of HES would induce the same result in non-septic patients in the intensive care unit (ICU) remains unclear. The objective of this meta-analysis was to evaluate 6% HES versus other fluids for non-septic ICU patients.

METHODS

Randomized controlled trials (RCTs) were searched from Pubmed, OvidSP, Embase database and Cochrane Library, published before November, 2013. A meta-analysis was made on the effect of 6% HES versus other fluids for non-septic ICU patients, including mortality, RRT incidence, bleeding volume, red blood cell (RBC) transfusion and fluid application for non-septic patients in ICU.

RESULTS

Twenty-two RCTs were included, involving 6,064 non-septic ICU patients. Compared with the other fluids, 6% HES was not associated with decreased overall mortality (RR = 1.03, 95%CI: 0.09 to 1.17; P = 0.67; I(2) = 0). There was no significant difference in RRT incidence, bleeding volume and red blood cell transfusion between 6% HES group and the other fluid groups. However, patients in HES group received less total intravenous fluids than those receiving crystalloids during the first day in ICU (SMD = -0.84; 95%CI: -1.39 to -0.30; P = 0.003, I(2) = 74%).

CONCLUSIONS

This meta-analysis found no increased mortality, RRT incidence, bleeding volumes or RBC transfusion in non-septic ICU patients, but the sample sizes were small and the studies generally were of poor quality.

The impact of hydroxyethyl starches in cardiac surgery: a meta-analysis

Introduction

Recent studies in septic patients showed that adverse effects of hydroxyethyl starches (HESs) possibly outweigh their benefits in severely impaired physiological haemostasis. It remains unclear whether this also applies to patient populations that are less vulnerable. In this meta-analysis, we evaluated the impact of various HES generations on safety and efficacy endpoints in patients undergoing cardiac surgery.

Methods

We searched the PubMed, Embase and Cochrane Central Register of Controlled Trials databases for randomised controlled trials (RCTs) in the English or German language comparing the use of HES to any other colloid or crystalloid during open heart surgery.

Results

Blood loss and transfusion requirements were higher for older starches with mean molecular weights more than 200 kDa compared to other volume substitutes. In contrast, this effect was not observed with latest-generation tetrastarches (130/0.4), which performed even better when compared to albumin (blood loss of tetrastarch versus albumin: standardised mean difference (SMD), −0.34; 95% CI, −0.63, −0.05; P = 0.02; versus gelatin: SMD, −0.06; 95% CI, −0.20, 0.08; P = 0.39; versus crystalloids: SMD, −0.05; 95% CI, −0.20, 0.10; P = 0.54). Similar results were found for transfusion needs. Lengths of stay in the intensive care unit or hospital were significantly shorter with tetrastarches compared to gelatin (intensive care unit: SMD, −0.10; 95% CI, −0.15, −0.05; P = 0.0002) and crystalloids (hospital: SMD, −0.52; 95% CI, −0.90, −0.14; P = 0.007).

Conclusions

In this meta-analysis of RCTs, we could not identify safety issues with tetrastarches compared with other colloid or crystalloid solutions in terms of blood loss, transfusion requirements or hospital length of stay in patients undergoing cardiac surgery. The safety data on coagulation with older starches raise some issues that need to be addressed in future trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0656-0) contains supplementary material, which is available to authorized users.