Perioperative Fluid Therapy With Tetrastarch and Gelatin in Cardiac Surgery—A Prospective Sequential Analysis*:

Use of colloids and crystalloids for perioperative clinical infusion management in cardiac surgery patients and postoperative outcomes: a meta-analysis

BACKGROUND

The optimal fluid management strategy for patients undergoing cardiac surgery was controversial regarding fluid volume and intraoperative fluid types. This study aimed to assess the correlation between colloids and crystalloids used for perioperative fluid therapy in cardiac surgery patients and postoperative prognosis.

METHODS

The Ovid MEDLINE(R) ALL, Embase, and Cochrane Central Register of Controlled Trials databases were searched for eligible studies on fluid management strategies using colloids and crystalloids for cardiac surgery patients published before August 25th, 2023.

RESULTS

Ten randomized controlled trials met the eligibility criteria. Compared to the use of crystalloids, the use of colloids, including hydroxyethyl starch (HES), albumin, and gelatine, did not show any differences in mortality, transfusion, acute kidney injury, and atrial fibrillation rates, postoperative blood loss, the length of hospital stay, or the length of intensive care unit (ICU) stay. The results of this meta-analysis showed that the crystalloid group had significantly reduced postoperative chest tube output compared to the colloid group. In the subgroup analysis, the amount of fresh frozen plasma (FFP) infused was significantly lower when using fluid management in the ICU and when using isotonic crystalloids compared to the colloids. In addition, when using fluid management in the ICU, patients in the colloid group had a significant increase in urine volume 24 h after surgery. However, other related factors, including the type of crystalloid solution, type of colloidal solution, and timing of liquid management, did not affect most outcomes.

CONCLUSION

Both colloids and crystalloids could be used as alternatives for perioperative fluid management after cardiac surgery. The use of crystalloids significantly reduced the postoperative chest tube output, and the need for FFP infusion decreased significantly with the use of isotonic crystalloids or fluid management during the ICU stay. ICU patients in the colloid group had higher urine output 24 h after surgery. In addition, although the infusion method was not related to most outcomes, the rates of red blood cell and FFP transfusion and postoperative blood loss in the crystalloid group seemed to be lower, which needed to be further studied in high-quality and large-sample RCTs.

TRIAL REGISTRATION

PROSPERO, CRD42023415234.

Comparison of six percent hydroxyethyl starch 130/0.4 and ringer's lactate as priming solutions in patients undergoing isolated open heart valve surgery: A double-blind randomized controlled trial

OBJECTIVES

Colloids are added to the priming solution of the cardiopulmonary bypass (CPB) pump to maintain colloid osmotic pressure and prevent fluid overload. This study aimed to compare the effects of 6% hydroxyethyl starch (HES) 130/0.4 and ringer's lactate (RL) priming solution on patients' outcomes undergoing isolated heart valve surgery with CPB.

METHODS

This randomized clinical trial included one hundred and 20 patients undergoing heart valve surgery, and those were allocated into two groups. Patients in the RL group received 1500 mL of RL, and those in the RL + HES group were given 500 mL of HES and 1000 mL of RL.

RESULTS

The patients' median age was 52 (IQR 42-60) and 50 (IQR 40-61) years in the RL + HES and the RL group, respectively (p = .71). The number of cases that required blood product transfusion in both the operating room and intensive care unit was also significantly higher in the RL + HES group compared to the RL group (RR 2.04, 95% CI 1.50-2.76; p < .01 and RR 1.42, 95% CI 1.01-2.01; p = .05, respectively). Declines in postoperative creatinine levels and platelet counts were higher in the RL + HES compared to the RL group (between-subjects effect p = .007 and p = .038, respectively), while the incidence of acute kidney injury was comparable between groups (RR 0.66, 95% CI 0.13-3.30; p = .55).

CONCLUSIONS

Among patients undergoing heart valve surgery with CPB, 6% HES added to RL for priming compared with only RL increased the risk of the need for blood product transfusion over the hospitalization period.

Perioperative Gelatin Use Is Associated With Increased Complication Rates and Does Not Prevent Postoperative Fluid Overload in Patients Undergoing Elective Cardiac Surgery

OBJECTIVES

The benefit of using gelatin solution in cardiac surgery is still controversial. Previous data suggested adverse interactions of gelatin infusion with acute kidney injury (AKI) or coagulopathy. The purpose of this study was to evaluate the association between perioperative gelatin use and fluid overload (FO), hemodynamic stability, and outcomes compared to crystalloid-based fluid management.

DESIGN

A retrospective study design.

SETTING

At a single-center tertiary university setting.

PARTICIPANTS

Propensity score-matched cohort study of 191 pairs of patients scheduled for cardiac surgery.

INTERVENTIONS

Patients received either gelatin + crystalloid or pure crystalloid-based perioperative fluid management. The primary outcomes were the frequency of FO and hemodynamic stability defined by the vasoactive-inotropic score. Postoperative complications and 3-year survival were analyzed also.

MEASUREMENTS AND MAIN RESULTS

Patients who received gelatin experienced more frequent postoperative FO than controls (11.0% v 3.1%, p = 0.006) despite comparable hemodynamic stability in both groups. Gelatin administration was linked with a higher rate of postoperative complications, including blood loss, AKI, and new-onset postoperative atrial fibrillation. Use of gelatin infusion resulted in an adjusted odds ratio of 1.982 (95% CI 1.051-3.736, p = 0.035) for developing early postoperative AKI. This study confirmed a dose-dependent relationship between gelatin infusion and AKI. Thirty-day mortality and 3-year survival were similar in the groups.

CONCLUSIONS

Gelatin administration versus crystalloid fluid management showed a significant association with a higher rate of FO and an increased risk for early postoperative AKI in a dose-dependent manner.

Review of Postoperative Care for Heart Transplant Recipients

The early postoperative management strategies after heart transplantation include optimizing the function of the denervated heart, correcting the causes of hemodynamic instability, and initiating and maintaining immunosuppressive therapy, allograft rejection surveillance, and prophylaxis against infections caused by immunosuppression. The course of postoperative support is influenced by the quality of allograft myocardial protection prior to implantation and reperfusion, donor-recipient heart size matching, surgical technique of orthotopic heart transplantation, and patient factors (eg, preoperative condition, immunologic compatibility, postoperative vasomotor tone, severity and reversibility of pulmonary vascular hypertension, pulmonary function, mediastinal blood loss, and end-organ perfusion). This review provides an overview of the early postoperative care of recipients and includes a brief description of the surgical techniques for orthotopic heart transplantation.

ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy

Acute kidney injury (AKI) is a complex syndrome with a high incidence and considerable morbidity in critically ill patients. Renal replacement therapy (RRT) remains the mainstay of treatment for AKI. There are at present multiple disparities in uniform definition, diagnosis, and prevention of AKI and timing of initiation, mode, optimal dose, and discontinuation of RRT that need to be addressed. The Indian Society of Critical Care Medicine (ISCCM) AKI and RRT guidelines aim to address the clinical issues pertaining to AKI and practices to be followed for RRT, which will aid the clinicians in their day-to-day management of ICU patients with AKI.

How to cite this article

Mishra RC, Sodhi K, Prakash KC, Tyagi N, Chanchalani G, Annigeri RA, et al. ISCCM Guidelines on Acute Kidney Injury and Renal Replacement Therapy. Indian J Crit Care Med 2022;26(S2):S13-S42.

Gelatin and the risk of acute kidney injury after cardiac surgery

BACKGROUND

Gelatin has been used as a plasma volume expander because of its ability to preserve intravascular volume more effectively than crystalloids. However, gelatin may have detrimental effects on kidney function and increase the risk of acute kidney injury (AKI).

METHOD

We investigated by retrospective analysis of prospectively collected data whether the administration of 4% succinyl gelatin is associated with an increased risk of AKI after cardiac surgery. We compared two propensity score-matched groups of 1,187 patients (crystalloid group and gelatin group).

RESULTS

The incidence of AKI was similar in both groups (gelatin 21% and crystalloid 20%) (p = 0.414). The incidence of moderate AKI (8% vs. 6%) was higher in the gelatin group, but there was no difference in mild or severe AKI. Postoperative serum creatine on the first (70 vs. 70 μmol L^-1 , p = 0.689) or fourth (71 vs. 70, p = 0.313) postoperative day was similar between groups and there was no difference in the need for new renal replacement therapy (p = 0.999). Patients in the gelatin group received less crystalloids (2080 ml vs. 4130 ml, p = 0.001) and total fluids (3760 ml vs. 4180 ml, p = 0.001), their fluid balance was less positive (p = 0.001) and they required less vasoactive and inotropic medication (p = 0.001). Gelatin was not associated with increased mortality compared to the crystalloid group.

CONCLUSION

Gelatin was not associated with AKI after cardiac surgery.

Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Acute kidney injury (AKI) is a serious clinical syndrome, and one of the common comorbidities in the perioperative period. AKI can lead to complications in surgical patients and is receiving increasing attention in clinical workup. In recent years, the analysis of perioperative risk factors has become more in-depth and detailed. In this review, the definition, diagnosis, and pathophysiological characteristics of perioperative AKI are reviewed, and the main risk factors for perioperative AKI are analyzed, including advanced age, gender, certain underlying diseases, impaired clinical status such as preoperative creatinine levels, and drugs that may impair renal function such as non-steroidal anti-inflammatory drugs (NASIDs), ACEI/ARB, and some antibiotics. Injectable contrast agents, some anesthetic drugs, specific surgical interventions, anemia, blood transfusions, hyperglycemia, and malnutrition are also highlighted. We also propose potential preventive and curative measures, including the inclusion of renal risk confirmation in the preoperative assessment, minimization of intraoperative renal toxin exposure, intraoperative management and hemodynamic optimization, remote ischemic preadaptation, glycemic control, and nutritional support. Among the management measures, we emphasize the need for careful perioperative clinical examination, timely detection and management of AKI complications, administration of dexmedetomidine for renal protection, and renal replacement therapy. We aim that this review can further increase clinicians' attention to perioperative AKI, early assessment and intervention to try to reduce the risk of AKI.

A randomised controlled trial of succinylated gelatin (4%) fluid on urinary acute kidney injury biomarkers in cardiac surgical patients

Background

Fluid resuscitation is frequently required for cardiac surgical patients admitted to the intensive care unit. The ideal fluid of choice in regard to efficacy and safety remains uncertain. Compared with crystalloid fluid, colloid fluid may result in less positive fluid balance. However, some synthetic colloids are associated with increased risk of acute kidney injury (AKI). This study compared the effects of succinylated gelatin (4%) (GEL) with compound sodium lactate (CSL) on urinary AKI biomarkers in patients after cardiac surgery.

Methods

Cardiac surgical patients who required an intravenous fluid bolus of at least 500 mL postoperatively were randomly allocated to receive GEL or CSL as the resuscitation fluid of choice for the subsequent 24 h. Primary outcomes were serial urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C concentrations measured at baseline, 1 h, 5 h and 24 h after enrolment, with higher concentrations indicating greater kidney injury. Secondary biomarker outcomes included urinary clusterin, α1-microglobulin and F₂-isoprostanes concentrations. Differences in change of biomarker concentration between the two groups over time were compared with mixed-effects regression models. Statistical significance was set at P < 0.05.

Results

Forty cardiac surgical patients (n = 20 per group) with similar baseline characteristics were included. There was no significant difference in the median volume of fluid boluses administered over 24 h between the GEL (1250 mL, Q1–Q3 500–1750) and CSL group (1000 mL, Q1–Q3 500–1375) (P = 0.42). There was a significantly greater increase in urinary cystatin C (P < 0.001), clusterin (P < 0.001), α1-microglobulin (P < 0.001) and F₂-isoprostanes (P = 0.020) concentrations over time in the GEL group, compared to the CSL group. Change in urinary NGAL concentration (P = 0.68) over time was not significantly different between the groups. The results were not modified by adjustment for either urinary osmolality or EuroSCORE II predicted risk of mortality.

Conclusions

This preliminary randomised controlled trial showed that use of succinylated gelatin (4%) for fluid resuscitation after cardiac surgery was associated with increased biomarker concentrations of renal tubular injury and dysfunction, compared to crystalloid fluid. These results generate concern that use of intravenous gelatin fluid may contribute to clinically relevant postoperative AKI.

Trial registration ANZCTR.org.au, ACTRN12617001461381. Registered on 16th October, 2017, http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373619&isReview=true.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-021-00412-9.

The comparison of albumin and 6% hydroxyethyl starches (130/0.4) in cardiac surgery: a meta-analysis of randomized controlled clinical trials

Background

Fluid administration is a key tool in the maintenance of normovolemia in patients with cardiac surgery. The trials that evaluated the safety of 6% hydroxyethyl starch (HES) 130/0.4 in cardiac surgical patients were inconsistent. It is necessary to compare the efficacy and safety of albumin and 6% HES (130/0.4).

Method

We searched for the randomized controlled clinical trials that compared human albumin with 6% HES (130/0.4) in cardiac surgery in PubMed, Cochrane, and Embase.

Results

Ten studies involved a total of 1567 patients were included in our meta-analysis. For the efficiency, there was no difference in total volume of infusion between compared groups [P = 0.64, Fixed Effect Model (FEM): standardized mean difference (SMD) = 0.04, 95% confidence interval (CI) (− 0.12, 0.20)]. As for safety, the albumin show more risk than hydroxyethyl starch 130/0.4 in blood loss [P = 0.02, FEM: SMD: 0.22, 95% CI (0.03, 0.41)]. There was no difference in the frequency of transfusions (P = 0.20, RR = 1.11; 95% CI (0.95, 1.27)) between the two groups. No difference was observed for the days in intensive care unit [P = 0.05, FEM: SMD = − 0.18, 95% CI (− 0.36, 0.00)], and the days in hospital [P = 0.32, FEM: SMD = − 0.11, 95% CI (− 0.32, 0.10)]. Furthermore, both the incidence of AKI, RRT, and mortality were comparable in the two groups.

Conclusion

This study provided evidence that the 6% HES (130/0.4) might be the substitute for HA, which reduced the economic burden for patients with cardiac surgery. However, the effect of 6% HES (130/0.4) and HA on AKI still needs to be further studied.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-021-01340-x.

Hydroxyethyl starch and acute kidney injury in high-risk patients undergoing cardiac surgery: A prospective multicenter study

BACKGROUND

Hydroxyethyl starch (HES) solutions increase the risk of acute kidney injury (AKI) in critically ill patients admitted to intensive care unit (ICU) for medical indications. We conducted a cohort study to evaluate the renal safety of modern 6% HES solutions in high-risk patients having cardiac surgery.

METHOD

In this multicentre prospective cohort study, we recruited 261 consecutive patients at high-risk for developing cardiac surgery-associated AKI, based on a Cleveland score ≥ 4 points, from July to December 2017th in 14 hospitals in Spain and the United Kingdom. Multivariable logistic regression modeling and propensity-score matched-pairs analysis were used to determine the adjusted association between administration of HES and AKI.

RESULTS

Of the cohort, 95 patients (36.4%) received 6% HES 130/0.4 either intraoperatively or postoperatively. Postoperative AKI occurred in 145 patients (55.5%). The unadjusted odds of AKI was significantly higher in the HES group, when compared to those not receiving HES (OR 2.22, 95% CI 1.30-3.80, p = 0.003). In multivariable logistic regression models, modern HES was not associated with significantly increased risk of AKI (adjusted OR 0.84, 95% CI 0.41-1.71, p = 0.63). In propensity score match-pairs analysis of 188 patients, the HES group experienced similar adjusted odds of AKI (OR 1.05, CI 95% 0.87-1.27, p = 0.57) and RRT (OR 1.06, CI 95% 0.92-1.22, p = 0.36).

CONCLUSIONS

The use of modern hydroxyethyl starch 6% HES 130/0.4 was not associated with an increased risk of AKI nor dialysis in this cohort of patients at elevated risk for developing AKI after cardiac surgery.

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.

Use of matching methods in observational studies with critical patients and renal outcomes. Scoping review

Introduction: The use of matching techniques in observational studies has been increasing and is not always used appropriately. Clinical experiments are not always feasible in critical patients with renal outcomes, and observational studies are an important alternative. Objective: Through a scoping review, determine the available evidence on the use of matching methods in studies involving critically ill patients and assessing renal outcomes. Methods: Medline, Embase, and Cochrane databases were used to identify articles published between 1992 and 2020 up to week 10, which studied different exposures in the critically ill patient with renal outcomes and used propensity matching methods. Results: Most publications are cohort studies 94 (94. 9 %), five studies (5. 1 %) were cross-sectional. The main pharmacological intervention was the use of antibiotics in seven studies (7. 1%) and the main risk factor studied was renal injury prior to ICU admission in 10 studies (10. 1%). The balance between the baseline characteristics assessed by standardized means, in only 28 studies (28. 2%). Most studies 95 (96 %) used logistic regression to calculate the propensity index. Conclusion: Major inconsistencies were observed in the use of methods and in the reporting of findings. A summary is made of the aspects to be considered in the use of the methods and reporting of the findings with the matching by propensity index.

Effect of 6% hydroxyethyl starch 130/0.4 on kidney and haemostatic function in cardiac surgical patients: a randomised controlled trial

Whether third‐generation hydroxyethyl starch solutions provoke kidney injury or haemostatic abnormalities in patients having cardiac surgery remains unclear. We tested the hypotheses that intra‐operative administration of a third‐generation starch does not worsen postoperative kidney function or haemostasis in cardiac surgical patients compared with human albumin 5%. This triple‐blind, non‐inferiority, clinical trial randomly allocated patients aged 40–85 who underwent elective aortic valve replacement, with or without coronary artery bypass grafting, to plasma volume replacement with 6% starch 130/0.4 vs. 5% human albumin. Our primary outcome was postoperative urinary neutrophil gelatinase‐associated lipocalin concentrations, a sensitive and early marker of postoperative kidney injury. Secondarily, we evaluated urinary interleukin‐18; acute kidney injury using creatinine RIFLE criteria, coagulation measures, platelet count and function. Non‐inferiority (delta 15%) was assessed with correction for multiple comparisons. We enrolled 141 patients (69 starch, 72 albumin) as planned. Results of the primary analysis demonstrated that postoperative urine neutrophil gelatinase‐associated lipocalin (median (IQR [range])) was slightly lower with hydroxyethyl starch (5 (1–68 [0–996]) ng.ml⁻¹) vs. albumin (5 (2–74 [0–1604]) ng.ml⁻¹), although not non‐inferior [ratio of geometric means (95%CI) 0.91 (0.57, 1.44); p = 0.15] due to higher than expected variability. Urine interleukin‐18 concentrations were reduced, but interleukin‐18 and kidney injury were again not non‐inferior. Of 11 individual coagulation measures, platelet count and function, nine were non‐inferior to albumin. Two remaining measures, thromboelastographic R value and arachidonic acid‐induced platelet aggregation, were clinically similar but with wide confidence intervals. Starch administration during cardiac surgery produced similar observed effects on postoperative kidney function, coagulation, platelet count and platelet function compared with albumin, though greater than expected variability and wide confidence intervals precluded the conclusion of non‐inferiority. Long‐term mortality and kidney function appeared similar between starch and albumin.

Hypertonic saline for fluid resuscitation after cardiac surgery (HERACLES): study protocol for a preliminary randomised controlled clinical trial

BACKGROUND

Intraoperative and postoperative management of cardiac surgery patients is complex, involving the application of differential vasopressors and volume therapy. It has been shown that a positive fluid balance has a major impact on postoperative outcome. Today, the advantages and disadvantages of buffered crystalloid solutes are a topic of controversy, with no consensus being reached so far. The use of hypertonic saline (HS) has shown promising results with respect to lower total fluid balance and postoperative weight gain in critically ill patients in preliminary studies. However, collection of more data on HS in critically ill patients seems warranted. This preliminary study aims to investigate whether fluid resuscitation using HS in patients following cardiac surgery results in less total fluid volume being administered.

METHODS

In a prospective double-blind randomised controlled clinical trial, we aim to recruit 96 patients undergoing elective cardiac surgery for ischaemic and/or valvular heart disease. After postoperative admission to the intensive care unit (ICU), patients will be randomly assigned to receive 5 ml/kg ideal body weight HS (7.3% NaCl) or normal saline (NS, 0.9% NaCl) infused within 60 min. Blood and urine samples will be collected preoperatively and postoperatively up to day 6 to assess changes in renal, cardiac, inflammatory, acid-base, and electrolyte parameters. Additionally, we will perform renal ultrasonography studies to assess renal blood flow before, during, and after infusion, and we will measure total body water using preoperative and postoperative body composition analysis (bioimpedance). Patients will be followed up for 90 days.

DISCUSSION

The key objective of this study is to assess the cumulative amount of fluid administered in the intervention (HS) group versus control (NS) group during the ICU stay. In this preliminary, prospective, randomised controlled clinical trial we will test the hypothesis that use of HS results in less total fluids infused and less postoperative weight gain when compared to the standard of intensive care in cardiac surgery patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03280745 . Registered on 12 September 2017.

Fluid management in patients undergoing cardiac surgery: effects of an acetate- versus lactate-buffered balanced infusion solution on hemodynamic stability (HEMACETAT)

BACKGROUND

Recent evidence suggests that acetate-buffered infusions result in better hemodynamic stabilization than 0.9% saline in patients undergoing major surgery. The choice of buffer in balanced crystalloid solutions may modify their hemodynamic effects. We therefore compared the inopressor requirements of Ringer's acetate and lactate for perioperative fluid management in patients undergoing cardiac surgery.

METHODS

Using a randomized controlled double-blind design, we compared Ringer's acetate (RA) to Ringer's lactate (RL) with respect to the average rate of inopressor administered until postoperative hemodynamic stabilization was achieved. Secondary outcomes were the cumulative dose of inopressors, the duration of inopressor administration, the total fluid volume administered, and the changes in acid-base homeostasis. Patients undergoing elective valvular cardiac surgery were included. Patients with severe cardiac, renal, or liver disease were excluded from the study.

RESULTS

Seventy-five patients were randomly allocated to the RA arm, 73 to the RL. The hemodynamic profiles were comparable between the groups. The groups did not differ with respect to the average rate of inopressors (RA 2.1 mcg/kg/h, IQR 0.5-8.1 vs. RL 1.7 mcg/kg/h, IQR 0.7-8.2, p = 0.989). Cumulative doses of inopressors and time on individual and combined inopressors did not differ between the groups. No differences were found in acid-base parameters and their evolution over time.

CONCLUSION

In this study, hemodynamic profiles of patients receiving Ringer's lactate and Ringer's acetate were comparable, and the evolution of acid-base parameters was similar. These study findings should be evaluated in larger, multi-center studies.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02895659 . Registered 16 September 2016.

The effects of perioperative intravenous fluid administration strategy on renal outcomes in patients undergoing cardiovascular surgery: An observational study

We assessed whether perioperative fluid management with balanced solutions and a limited volume of hydroxyethyl starch (renal-protective fluid management [RPF] strategy) could improve renal outcomes after cardiovascular surgery.For this retrospective observational study, we evaluated 2613 patients who underwent cardiovascular surgery from January 1, 2010 to December 31, 2013. The control group were given intravenous fluids with saline-based solutions and unlimited volumes of hydroxyethyl starch solutions and the RPF group were given intravenous fluids with RPF. The primary outcome was the incidence of acute kidney injury (AKI) and chronic dialysis within 12 months after cardiovascular surgery. Multivariable regression and propensity analyses were performed to evaluate the association between perioperative fluid management strategy and postoperative renal outcomes.Postoperative AKI and chronic dialysis occurred in 213 (21.2%) and 5 (0.5%) patients in the RPF group compared with 696 (43.2%) and 38 (2.4%) patients in the control group, respectively. After adjustment, the RPF group was linked to a decreased risk of postoperative AKI, severe AKI, persistent AKI, use of renal replacement therapy, chronic kidney disease, chronic dialysis, and a shorter postoperative extubation time and intensive care unit, and hospital stay duration.The perioperative fluid management strategy with balanced solutions and a limited volume of hydroxyethyl starch was related to improved acute and 1-year renal and clinical outcomes after cardiovascular surgery. These findings indicate the need for further definitive clinical trials on perioperative fluid management strategy.

Choice of fluids in critically ill patients

Background

Fluids are by far the most commonly administered intravenous treatment in patient care. During critical illness, fluids are widely administered to maintain or increase cardiac output, thereby relieving overt tissue hypoperfusion and hypoxia.

Main text

Until recently, because of their excellent safety profile, fluids were not considered “medications”. However, it is now understood that intravenous fluid should be viewed as drugs. They affect the cardiovascular, renal, gastrointestinal and immune systems. Fluid administration should therefore always be accompanied by careful consideration of the risk/benefit ratio, not only of the additional volume being administered but also of the effect of its composition on the physiology of the patient. Apart from the need to constantly assess fluid responsiveness, it is also important to periodically reconsider the type of fluid being administered and the evidence regarding the relationship between specific disease states and different fluid solutions.

Conclusions

The current review presents the state of the art regarding fluid solutions and presents the existing evidence on routine fluid management of critically ill patients in specific clinical settings (sepsis, Adult Respiratory Distress Syndrome, major abdominal surgery, acute kidney injury and trauma).

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0669-3) contains supplementary material, which is available to authorized users.

Does fluid management affect the occurrence of acute kidney injury?

PURPOSE OF REVIEW

To describe the potential impact of different fluid management strategies on renal outcomes in critically ill and postoperative patients.

RECENT FINDINGS

Uncritical fluid administration may induce renal compartment syndrome and renal venous congestion, which contribute to kidney dysfunction. In more than 5000 randomized surgical or septic patients, goal-directed therapy did not reduce fluid accumulation, acute kidney injury (AKI) development or need for renal replacement therapy. In contrast to synthetic colloids, which increase the risk of AKI, albumin solutions and balanced crystalloids appear well tolerated from a renal standpoint in medical and surgical patients requiring intensive care. However, any clinical benefits compared with 0.9% sodium chloride have not yet been demonstrated.

SUMMARY

Although synthetic colloids should be avoided in patients with or at risk of AKI, the renal efficacy of using albumin solutions and/or balanced crystalloids as alternatives to 0.9% sodium chloride in high-risk patients is yet to be confirmed or refuted. Improved goal-directed protocols, which minimize unnecessary fluid administration and reduce potentially harmful effects of fluid overload, need to be developed and tested.

Synthetic colloid resuscitation in severely injured patients: analysis of a nationwide trauma registry (TraumaRegister DGU)

The purpose of this study was to investigate the efficacy and safety of synthetic colloid resuscitation among severely injured patients. Fluid resuscitation of trauma patients of a nationwide trauma registry was analysed between 2002 and 2015. Effects of synthetic colloid resuscitation in the pre-hospital setting and emergency department on renal failure, renal replacement therapy and multiple organ failure were analysed among patients with ≥2 days intensive care unit stay, and in-hospital mortality was analysed among all patients. 48,484 patients with mean age of 49 years and mean injury severity score of 23 points were included; 72.3% were male and 95.5% had blunt trauma. Risk-adjusted analyses revealed that patients receiving >1,000 ml synthetic colloids experienced an increase of renal failure and renal replacement therapy rates (OR 1.42 and 1.32, respectively, both p ≤ 0.006). Any synthetic colloid use was associated with an increased risk of multiple organ failure (p < 0.001), but there was no effect on hospital mortality (p = 0.594). Between 2002 and 2015 usage of synthetic colloids dropped, likewise did total fluid intake and usage of blood products. The data from this analysis suggests that synthetic colloid resuscitation provides no beneficial effects and might be harmful in patients with severe trauma.

Update on perioperative acute kidney injury

PURPOSE OF REVIEW

In this review, we discuss the latest updates on perioperative acute kidney injury (AKI) and the specific considerations that are relevant to different surgeries and patient populations.

RECENT FINDINGS

AKI diagnosis is constantly evolving. New biomarkers detect AKI early and shed a light on the possible cause of AKI. Hypotension, even for a short duration, is associated with perioperative AKI. The debate on the deleterious effects of chloride-rich solutions is still far from conclusion. Remote ischemic preconditioning is showing promising results in the possible prevention of perioperative AKI. No definite data show a beneficiary effect of statins, fenoldepam, or sodium bicarbonate in preventing AKI.

SUMMARY

Perioperative AKI is prevalent and associated with significant morbidity and mortality. Considering the lack of effective preventive or therapeutic interventions, this review focuses on perioperative AKI: measures for early diagnosis, defining risks and possible mechanisms, and summarizing current knowledge for intraoperative fluid and hemodynamic management to reduce risk of AKI.

Crystalloid fluid choice in the critically ill : Current knowledge and critical appraisal

Intravenous infusion of crystalloid solutions is one of the most frequently administered medications worldwide. Available crystalloid infusion solutions have a variety of compositions and have a major impact on body systems; however, administration of crystalloid fluids currently follows a "one fluid for all" approach than a patient-centered fluid prescription. Normal saline is associated with hyperchloremic metabolic acidosis, increased rates of acute kidney injury, increased hemodynamic instability and potentially mortality. Regarding balanced infusates, evidence remains less clear since most studies compared normal saline to buffered infusion solutes.; however, buffered solutes are not homogeneous. The term "buffered solutes" only refers to the concept of acid-buffering in infusion fluids but this does not necessarily imply that the solutes have similar physiological impacts. The currently available data indicate that balanced infusates might have some advantages; however, evidence still is inconclusive. Taking the available evidence together, there is no single fluid that is superior for all patients and settings, because all currently available infusates have distinct differences, advantages and disadvantages; therefore, it seems inevitable to abandon the "one fluid for all" strategy towards a more differentiated and patient-centered approach to fluid therapy in the critically ill.

Does Fluid Type and Amount Affect Kidney Function in Critical Illness?

Acute kidney injury (AKI) is common, although commonly used clinical diagnostic markers are imperfect. Intravenous fluid administration remains a cornerstone of therapy worldwide, but there is minimal evidence of efficacy for the use of fluid bolus therapy outside of specific circumstances, and emerging evidence associates fluid accumulation with worse renal outcomes and even increased mortality among critically ill patients. Artificial colloid solutions have been associated with harm, and chloride-rich solutions may adversely affect renal function. Large trials to provide guidance regarding the optimal fluid choices to prevent or ameliorate AKI, and promote renal recovery, are urgently required.

The dose of hydroxyethyl starch 6% 130/0.4 for fluid therapy and the incidence of acute kidney injury after cardiac surgery: A retrospective matched study

The safety of hydroxyethyl starches (HES) is still under debate. No studies have compared different dosing regimens of HES in cardiac surgery. We analyzed whether the incidence of Acute Kidney Injury (AKI) differed taking into account a weight-adjusted cumulative dose of HES 6% 130/0.4 for perioperative fluid therapy. This retrospective cohort study included all adult patients undergoing elective or emergency cardiac surgery with or without cardiopulmonary bypass. Exclusion criteria were patients on renal replacement therapy (RRT), cardiac trauma surgery, heart transplantation, patients with ventricular assist devices, subjects who required a surgical revision for bleeding and those whose medical records were incomplete. Primary endpoint was AKI following the creatinine based RIFLE classification. Secondary endpoints were 30-day mortality and RRT. Patients were divided into 2 groups whether they had received a cumulative HES dose of < 30 mL/kg (Low HES) or ≥ 30 mL/kg (High HES) during the intra- and postoperative period. A total of 1501 patients were analyzed with 983 patients in the Low HES and 518 subjects in the High HES group. 185 (18.8%) patients in the Low HES and 119 (23.0%) patients in the High HES group developed AKI (P = 0.06). In multivariable regression analysis the dose of HES administered per weight was not associated with AKI. After case-control matching 217 patients were analyzed in each group. AKI occurred in 39 (18.0%) patients in the Low HES and 50 (23.0%) patients in the High HES group (P = 0.19). In conditional regression analysis performed on the matched groups a lower weight-adjusted dose of HES was significantly associated with a reduced incidence of AKI [(Odds Ratio (95% CI) = 0.825 (0.727-0.936); P = 0.003]. In the absence of any safety study the cumulative dose of modern HES in cardiac surgery should be kept less than 30 mL/kg.

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.

Fluid Composition and Clinical Effects

The range of intravenous fluids available for therapeutic use and the differing indications are diverse. A solid understanding of the composition of different types of fluids is essential to understanding the physiologic effects following administration and the appropriate clinical application. In this review, the authors describe the different fluids commonly available and discuss the potential benefits and harms depending on the clinical circumstances.

An analysis of surgical and anaesthetic factors affecting skin graft viability in patients admitted to a Burns Intensive Care Unit

After large burns injuries, patients require fluid to be given via an IV drip. This is often very large volumes of fluid, much higher than would normally be required in other medical conditions. When the area of burn is very large multiple operations are often required and during these operations, IV fluids are again used to keep the blood pressure normal and keep the patient hydrated. We looked at the hospital records of 35 patients to see if there was any link between the drugs and fluids given during these operations and the success of the skin grafts performed in these operations. We found that using a particular type of fluid called a colloid fluid, which allows smaller volumes to be given for the same effect on blood pressure and hydration, was more common in patients whose skin grafts subsequently required further surgery due to poor healing. A larger study would now be required to see if this type of fluid is causing poor healing or whether it is a coincidental finding only.

Are all fluids bad for the kidney?

PURPOSE OF REVIEW

To describe the harmful effects of intravenous fluids on kidney structure and function and summarize recent comparisons between different fluids and their effect on kidney outcome.

RECENT FINDINGS

Administration of intravenous fluids may contribute to the development and sustention of acute kidney injury. In excess, fluids cause kidney interstitial edema and venous congestion, which prevents renal blood flow and glomerular filtration rate. In contrast to balanced crystalloids, chloride-rich solutions impair renal blood flow via autoregulatory mechanisms. Synthetic colloids, such as hydroxyethyl starches, gelatins, and dextrans are potentially nephrotoxic because they can cause osmotic nephrosis, which, in susceptible patients, might precede permanent kidney damage. Albumin solutions appear well tolerated to use in septic patients, although their renal efficacy over balanced crystalloids is not established. In contrast, administration of albumin solutions to patients with decompensated liver failure effectively prevents and ameliorates hepatorenal syndrome.

SUMMARY

Being nephrotoxic, synthetic colloids should be avoided in patients with reduced renal reserve, such as in critically ill patients and in patients with preexisting renal dysfunction. Suggested adverse effects with chloride-rich solutions need confirmation from ongoing trials. Albumin solutions are well tolerated in patients with sepsis and/or liver failure and improve outcomes in the latter.