Comparison of the effects of normal saline versus Plasmalyte on acid-base balance during living donor kidney transplantation using the Stewart and base excess methods

Balanced Crystalloids Versus Normal Saline in Kidney Transplant Patients: An Updated Systematic Review, Meta-analysis, and Trial Sequential Analysis

BACKGROUND

The use of balanced crystalloids over normal saline for perioperative fluid management during kidney transplantation and its benefits on acid-base and electrolyte balance along with its influence on postoperative clinical outcomes remains a topic of controversy. Therefore, we conducted this review to assess the impact of balanced solutions compared to normal saline on outcomes for kidney transplant patients.

METHODS

We searched MEDLINE, EMBASE, and Cochrane databases for randomized controlled trials (RCTs) comparing balanced lower-chloride solutions to normal saline in renal transplant patients. Our main outcome of interest was delayed graft function (DGF). Additionally, we examined acid-base and electrolyte measurements, along with postoperative renal function. We computed relative risk (RR) using the Mantel-Haenszel test for binary outcomes, and mean difference (MD) for continuous data, and applied DerSimonian and Laird random-effects models to address heterogeneity. Furthermore, we performed a trial sequential analysis (TSA) for all outcomes.

RESULTS

Twelve RCTs comprising a total of 1668 patients were included; 832 (49.9%) were assigned to receive balanced solutions. Balanced crystalloids reduced the occurrence of DGF compared to normal saline, with RR of 0.82 (95% confidence interval [CI], 0.71-0.94), P = .005; I² = 0%. The occurrence was 25% (194 of 787) in the balanced crystalloids group and 34% (240 of 701) in the normal saline group. Moreover, our TSA supported the primary outcome result and suggests that the sample size was sufficient for our conclusion. End-of-surgery chloride (MD, -8.80 mEq·L -1 ; 95% CI, -13.98 to -3.63 mEq.L -1 ; P < .001), bicarbonate (MD, 2.12 mEq·L -1 ; 95% CI, 1.02-3.21 mEq·L -1 ; P < .001), pH (MD, 0.06; 95% CI, 0.04-0.07; P < .001), and base excess (BE) (MD, 2.41 mEq·L -1 ; 95% CI, 0.88-3.95 mEq·L -1 ; P = .002) significantly favored the balanced crystalloids groups and the end of surgery potassium (MD, -0.17 mEq·L -1 ; 95% CI, -0.36 to 0.02 mEq·L -1 ; P = .07) did not differ between groups. However, creatinine did not differ in the first (MD, -0.06 mg·dL -1 ; 95% CI, -0.38 to 0.26 mg·dL -1 ; P = .71) and seventh (MD, -0.06 mg·dL -1 ; 95% CI, -0.18 to 0.06 mg·dL -1 ; P = .30) postoperative days nor urine output in the first (MD, -1.12 L; 95% CI, -3.67 to 1.43 L; P = .39) and seventh (MD, -0.01 L; 95% CI, -0.45 to 0.42 L; P = .95) postoperative days.

CONCLUSIONS

Balanced lower-chloride solutions significantly reduce the occurrence of DGF and provide an improved acid-base and electrolyte control in patients undergoing kidney transplantation.

Perioperative balanced crystalloids versus normal saline during kidney transplantation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

In kidney transplant (KT) surgery, the perioperative administration of intravenous (IV) fluids plays a crucial role, with potential effects on graft function. Our meta-analysis aims to assess the post-KT outcomes of perioperative balanced crystalloids (BC) versus normal saline (NS).

METHODS

We conducted a comprehensive search across five databases to identify relevant randomized controlled trials (RCTs). The search results were imported into Covidence for article eligibility screening, and all relevant outcome data were synthesized using risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CIs) in meta-analysis models within RevMan 5.4.

PROSPERO ID

CRD42023448457.

RESULTS

Pooled data from 15 RCTs with 2,008 participants showed that the rate of delayed graft function (DGF) was significantly lower with BC (RR: 0.78, 95% CI [0.68, 0.91], P = 0.0009). Also, BC was associated with significantly higher post-op blood pH (MD: 0.05, 95% CI [0.03, 0.07], P < 0.01), lower serum chloride (MD: - 7.31, 95% CI [- 10.58, - 3.77], P < 0.01), and sodium (MD: - 1.94, 95% CI [- 3.32, - 0.55], P = 0.006) as compared to NS. However, serum potassium, serum creatinine, and urine output at POD 1 to 7 did not differ between the two groups.

CONCLUSION

BC significantly reduced the incidence of DGF, resulting in more stable post-operative acid-base parameters, and lower chloride levels compared to NS. Hence, substituting NS with BC offers a strategy to protect grafts from acidotic and hyperchloremic insults, optimizing KT outcomes.

Effects of Balanced Versus Saline-based Solutions on Acute Kidney Injury in Off-pump Coronary Artery Bypass Surgery: A Randomized Controlled Trial

OBJECTIVES

To determine whether balanced solutions can reduce the incidence of acute kidney injury after off-pump coronary artery bypass surgery compared with saline.

DESIGN

Randomized controlled trial.

SETTING

Single tertiary care center.

PARTICIPANTS

Patients who underwent off-pump coronary artery bypass surgery between June 2014 and July 2020.

INTERVENTIONS

Balanced solution-based chloride-restrictive intravenous fluid strategy.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was acute kidney injury within 7 postoperative days, as defined by the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guideline. The incidence of acute kidney injury was 4.4% (8/180) in the balanced group and 7.3% (13/178) in the saline group. The difference was not statistically significant (risk difference, -2.86%; 95% confidence interval [CI], -7.72% to 2.01%; risk ratio, 0.61, 95% CI, 0.26 to 1.43; p = 0.35). Compared with the balanced group, the saline group had higher levels of intraoperative serum chloride and lower base excess, which resulted in a lower pH.

CONCLUSIONS

In patients undergoing off-pump bypass surgery with a normal estimated glomerular filtration rate, the intraoperative balanced solution-based chloride-restrictive intravenous fluid administration strategy did not decrease the rate of postoperative acute kidney injury compared with the saline-based chloride-liberal intravenous fluid administration strategy.

A Comparison Between Saline and Balanced Solutions in Kidney Transplants: A Randomized Clinical Trial

Objective This study aimed to investigate the impact of different types of intravenous fluids - normal saline (NS), lactated Ringer's solution (LR), and PlasmaLyte (PL) - on the acid-base balance and electrolyte concentration following kidney transplant, a common procedure for patients with end-stage renal disease (ESRD). Methodology A randomized controlled trial design was employed, wherein the primary parameters analyzed were postoperative pH and serum potassium levels. Postoperative concentrations of serum bicarbonate, sodium, chloride, and creatinine, as well as graft functionality, were assessed as secondary outcomes. These measurements were performed at the start and end of surgery, as well as 24 and 72 hours postoperatively. Results A total of 53 patients were included in the study and randomized into three cohorts: NS, LR, and PL, each of which showed comparability in terms of demographic and transplantation specifics. Notably, patients in the NS group exhibited a more significant decrease in pH (NS group: 7.285 ±0.098, LR group: 7.324 ±0.075, PL group: 7.7338 ±0.059) and bicarbonate levels (17.0 ±4.2, 20.9 ±2.8, 20.0 ±4.5) post 24 hours after the operation and displayed a similar pattern immediately after the surgery. However, there were no discernible differences in potassium (p=0.460), sodium (p=0.681), and chloride (p=0.321) levels across the groups. Furthermore, the study did not observe any significant differences in postoperative graft functionality. Conclusion The use of NS as the intraoperative fluid of choice led to lower pH and bicarbonate levels following kidney transplant, as compared to LR and PL. However, these results did not correlate with improvements in graft functionality.

Crystalloid Solutions in Hospital: A Review of Existing Literature

Intravenous fluids (IVF) like normal saline (NS) and Ringer's lactate (RL) are often crucial in the management of hospitalized patients. Mishandling these fluids can lead to complications in about 20% of patients receiving them. In this review, we present the current evidence through the identification of observational studies and randomized trials that observed the optimal use of IVF. We found that NS may cause hyperchloremic metabolic acidosis in surgical patients, but there is no clear difference in mortality and long-term outcomes between NS and balanced crystalloids. Critically ill patients, particularly those in sepsis, benefit from balanced crystalloids, as high chloride content fluids like NS increase the risk of complications and mortality. In pancreatitis, NS has been shown to increase the risk of ICU admission when compared to RL; however, there is no significant difference in long-term outcomes and mortality between the fluids. RL is preferred for burns due to its isotonicity and lack of protein, preventing edema formation in an already dehydrated state. Plasma-lyte may resolve diabetic ketoacidosis faster, while prolonged NS use can lead to metabolic acidosis, acute kidney injury, and cerebral edema. In conclusion, NS, RL, and plasma-lyte are the most commonly used isotonic IVF in the hospital population. Incorrect choice of fluids in a different clinical scenario can lead to worse outcomes.

Perioperative Fluid Management in Surgical Patients: A Review

Intravenous (IV) fluids are one of the most widely prescribed medications. Despite their frequent usage, IV fluids are often not used appropriately. High-quality evidence to guide the surgeon in the perioperative period is sparse. A plethora of choices for IV fluids exists with limited evidence to help guide the surgeon in specific patient populations and situations. To address this, the authors have set out to provide a critical review of commonly used IV fluids to treat surgical patients. Gaps in the existing literature for the surgical population will also be discussed as potential target areas for future research.

Balanced Crystalloids versus Normal Saline in Adults with Sepsis: A Comprehensive Systematic Review and Meta-Analysis

The crystalloid fluid of choice in sepsis remains debatable. We aimed to perform a comprehensive meta-analysis to compare the effect of balanced crystalloids (BC) vs. normal saline (NS) in adults with sepsis. A systematic search of PubMed, EMBASE, and Web of Sciences databases through 22 January 2022, was performed for studies that compared BC vs. NS in adults with sepsis. Our outcomes included mortality and acute kidney injury (AKI), need for renal replacement therapy (RRT), and ICU length of stay (LOS). Pooled risk ratio (RR) and mean difference (MD) with the corresponding 95% confidence intervals (CIs) were obtained using a random-effect model. Fifteen studies involving 20,329 patients were included. Overall, BC showed a significant reduction in the overall mortality (RR 0.88, 95% CI 0.81-0.96), 28/30-day mortality (RR 0.87, 95% CI 0.79-0.95), and AKI (RR 0.85, 95% CI 0.77-0.93) but similar 90-day mortality (RR 0.96, 95% CI 0.90-1.03), need for RRT (RR 0.91, 95% CI 0.76-1.08), and ICU LOS (MD -0.25 days, 95% CI -3.44, 2.95), were observed between the two groups. However, subgroup analysis of randomized controlled trials (RCTs) showed no statistically significant differences in overall mortality (RR 0.92, 95% CI 0.82-1.02), AKI (RR 0.71, 95% CI 0.47-1.06), and need for RRT (RR 0.71, 95% CI 0.36-1.41). Our meta-analysis demonstrates that overall BC was associated with reduced mortality and AKI in sepsis compared to NS among patients with sepsis. However, subgroup analysis of RCTs showed no significant differences in both overall mortality and AKI between the groups. There was no significant difference in the need for RRT or ICU LOS between BC and NS. Pending further data, our study supports using BC over NS for fluid resuscitation in adults with sepsis. Further large-scale RCTs are necessary to validate our findings.

Effects of the Type of Intraoperative Fluid in Living Donor Kidney Transplantation: A Single-Center Retrospective Cohort Study

PURPOSE

Perioperative fluid management in kidney transplant recipients is crucial to supporting the fluid, acid-base, and electrolyte balance required for graft perfusion. However, the choice of intraoperative crystalloids in kidney transplantation remains controversial. We conducted a single-center retrospective cohort study to evaluate the impact of intraoperative fluids on acid-base and electrolyte balance and graft outcomes.

MATERIALS AND METHODS

We included 282 living donor kidney transplant recipients from January 2010 to December 2017. Patients were classified into two groups based on the type of intraoperative crystalloids used (157 patients in the half saline group and 125 patients in the balanced crystalloid solutions group, Plasma-lyte).

RESULTS

Compared with the half saline group, the Plasma-lyte group showed less metabolic acidosis and hyponatremia during surgery. Hyperkalemia incidence was not significantly different between the two groups. Changes in postoperative graft function assessed by blood urea nitrogen and creatinine were significantly different between the two groups. Patients in the Plasma-lyte group exhibited consistently higher glomerular filtration rates than those in the half saline group at 1 month and 1 year after transplantation after adjusting for demographic differences.

CONCLUSION

Intraoperative Plasma-lyte can lead to more favorable results in terms of acid-base balance during kidney transplantation. Patients who received Plasma-lyte showed superior postoperative graft function at 1 month and 1 year after transplantation. Further studies are needed to evaluate the superiority of intraoperative Plasma-lyte over other types of crystalloids in relation to graft outcomes.

Crystalloid fluids and delayed graft function in kidney transplant: A cohort study

Background:

Normal saline is commonly used in the perioperative kidney transplant period; its high chloride content can cause hyperchloremic metabolic acidosis giving a possible advantage to balanced electrolyte solutions due to their lower chloride content. The evidence regarding the best practices in fluid management during kidney transplantation and its effect on the incidence of delayed graft function (DGF) is still limited.

Materials and Methods:

One hundred thirty-eight patients were included and followed up for seven days after surgery. Administered crystalloid type and volume were compared among patients with and without DGF, along with additional patient and surgical variables. To investigate whether intraoperative fluid type/amount influence DGF, patients were categorized into three groups: those who received mainly (>50%) lactated Ringer's solution, normal saline, or plasmaLyte. A logistic regression analysis was used to define variables independently correlated with DGF, and odds ratios (OR) with a 95% confidence interval (CI) were reported.

Results:

The incidence of DGF was 8.7%. Cold ischemia time independently increased the odds of DGF (OR = 1.006 (95% CI: 1.002–1.011) while fluid type (saline versus PlasmaLyte OR = 5.28, 95% CI: 0.76–36.88) or amount (OR = 1.00, 95% CI: 1.00–1.01) did not significantly modify the odds of DGF. Central venous pressure, systolic blood pressure, and mean arterial pressure were higher in the non-DGF group, but this was not statistically significant (P > 0.05). Significant intraoperative acidosis developed in patients who received normal saline compared to those in PlasmaLyte and lactated Ringer's groups; however, acid–base balance and electrolytes did not vary significantly between the DGF and non-DGF groups.

Conclusion:

DGF was primarily influenced by surgical factors such as cold ischemia time, whereas intraoperative fluid type or amount did not affect DGF incidence.

Hemodynamic Instability During Liver Transplantation in Patients With End-stage Liver Disease: A Consensus Document from ILTS, LICAGE, and SATA

Hemodynamic instability (HDI) during liver transplantation (LT) can be difficult to manage and increases postoperative morbidity and mortality. In addition to surgical causes of HDI, patient- and graft-related factors are also important. Nitric oxide-mediated vasodilatation is a common denominator associated with end-stage liver disease related to HDI. Despite intense investigation, optimal management strategies remain elusive. In this consensus article, experts from the International Liver Transplantation Society, the Liver Intensive Care Group of Europe, and the Society for the Advancement of Transplant Anesthesia performed a rigorous review of the most current literature regarding the epidemiology, causes, and management of HDI during LT. Special attention has been paid to unique LT-associated conditions including the causes and management of vasoplegic syndrome, cardiomyopathies, LT-related arrhythmias, right and left ventricular dysfunction, and the specifics of medical and fluid management in end-stage liver disease as well as problems specifically related to portal circulation. When possible, management recommendations are made.

Battle of the Crystalloids in the Operating Room: A Literature Review

PURPOSE

The purpose of this article is to synthesize the evidence regarding the commonalities and differences between the three most common crystalloid solutions used in the operating room (normal saline [NS], lactated Ringer's [LR], and Plasmalyte [PL]) in order to determine best practice.

DESIGN

This study is an integrative review of literature.

METHODS

A review of the literature was conducted using the PubMed, CINAHL Plus, and Cochrane Library databases. The inclusion criteria included adult patients undergoing surgery who received either NS, LR, and/or PL (or similar solutions) for fluid maintenance therapy.

FINDINGS

A total of 15 articles from 2008 to 2020 conducted in a surgical setting were selected for the review; eleven randomized controlled studies, three observational studies, and one cohort-controlled trial.

CONCLUSIONS

The findings suggest balanced crystalloid solutions are superior to NS in the operating room in terms of maintaining a stable acid-base balance. PL is preferable to LR because it most closely resembles plasma concentration. Future research is needed to determine the cost-effectiveness of the solutions.

Fluid Management During Kidney Transplantation: A Consensus Statement of the Committee on Transplant Anesthesia of the American Society of Anesthesiologists

BACKGROUND

Intraoperative fluid management may affect the outcome after kidney transplantation. However, the amount and type of fluid administered, and monitoring techniques vary greatly between institutions and there are limited prospective randomized trials and meta-analyses to guide fluid management in kidney transplant recipients.

METHODS

Members of the American Society of Anesthesiologists (ASA) committee on transplantation reviewed the current literature on the amount and type of fluids (albumin, starches, 0.9% saline, and balanced crystalloid solutions) administered and the different monitors used to assess fluid status, resulting in this consensus statement with recommendations based on the best available evidence.

RESULTS

Review of the current literature suggests that starch solutions are associated with increased risk of renal injury in randomized trials and should be avoided in kidney donors and recipients. There is no evidence supporting the routine use of albumin solutions in kidney transplants. Balanced crystalloid solutions such as Lactated Ringer are associated with less acidosis and may lead to less hyperkalemia than 0.9% saline solutions. Central venous pressure is only weakly supported as a tool to assess fluid status.

CONCLUSIONS

These recommendations may be useful to anesthesiologists making fluid management decisions during kidney transplantation and facilitate future research on this topic.

Perioperative Normal Saline Administration and Delayed Graft Function in Patients Undergoing Kidney Transplantation: A Retrospective Cohort Study

BACKGROUND

Perioperative normal saline administration remains common practice during kidney transplantation. The authors hypothesized that the proportion of balanced crystalloids versus normal saline administered during the perioperative period would be associated with the likelihood of delayed graft function.

METHODS

The authors linked outcome data from a national transplant registry with institutional anesthesia records from 2005 to 2015. The cohort included adult living and deceased donor transplants, and recipients with or without need for dialysis before transplant. The primary exposure was the percent normal saline of the total amount of crystalloids administered perioperatively, categorized into a low (less than or equal to 30%), intermediate (greater than 30% but less than 80%), and high normal saline group (greater than or equal to 80%). The primary outcome was the incidence of delayed graft function, defined as the need for dialysis within 1 week of transplant. The authors adjusted for the following potential confounders and covariates: transplant year, total crystalloid volume, surgical duration, vasopressor infusions, and erythrocyte transfusions; recipient sex, age, body mass index, race, number of human leukocyte antigen mismatches, and dialysis vintage; and donor type, age, and sex.

RESULTS

The authors analyzed 2,515 records. The incidence of delayed graft function in the low, intermediate, and high normal saline group was 15.8% (61/385), 17.5% (113/646), and 21% (311/1,484), respectively. The adjusted odds ratio (95% CI) for delayed graft function was 1.24 (0.85 to 1.81) for the intermediate and 1.55 (1.09 to 2.19) for the high normal saline group compared with the low normal saline group. For deceased donor transplants, delayed graft function in the low, intermediate, and high normal saline group was 24% (54/225 [reference]), 28.6% (99/346; adjusted odds ratio, 1.28 [0.85 to 1.93]), and 30.8% (277/901; adjusted odds ratio, 1.52 [1.05 to 2.21]); and for living donor transplants, 4.4% (7/160 [reference]), 4.7% (14/300; adjusted odds ratio, 1.15 [0.42 to 3.10]), and 5.8% (34/583; adjusted odds ratio, 1.66 [0.65 to 4.25]), respectively.

CONCLUSIONS

High percent normal saline administration is associated with delayed graft function in kidney transplant recipients.

EDITOR’S PERSPECTIVE

Comparison of normal saline solution with low-chloride solutions in renal transplants: a meta-analysis

Background

Normal saline solution (NSS) has been the fluid of choice for renal transplant patients, but it can lead to hyperchloremic acidosis and hyperkalemia. This study was performed to compare the safety profile of low-chloride solutions with that of NSS in renal transplant patients.

Methods

We conducted a systemic review search on PubMed, Embase, and the Central Cochrane Registry. Randomized clinical trials (RCTs) and matched cohort studies involving NSS as the control arm and low-chloride solutions as an intervention arm were chosen. The standardized mean difference for continuous variables, the odds ratio (OR) for discrete variables, and a 95% confidence interval (CI) for effect sizes were used. A p-value of <0.05 was considered statistically significant. Analysis was performed using a random-effects model irrespective of heterogeneity, which was evaluated using I² statistics.

Results

Nine RCTs and one cohort study with a total of 726 patients were included. After transplantation, serum potassium was significantly lower in the low-chloride group (standardized mean difference compared to NSS group, –0.38 mEq/L; 95% CI, –0.66 to –0.11; p = 0.007). Similarly, postoperative chloride was lower in the low-chloride group (–2.41 mEq/L [–3.34 to –1.48], p < 0.001). No statistically significance was observed in delayed graft function (OR, 0.98 [0.56–1.69], p = 0.93), day 3 creatinine (–0.14 mg/dL [–0.46 to 0.18], p = 0.38), or day 7 urine output (–0.08 L [–0.29 to 0.12], p = 0.43).

Conclusion

Use of NSS during renal transplant leads to increased incidence of hyperchloremic acidosis with subsequent hyperkalemia, but clinical significance in the form of delayed graft function or postoperative creatinine remains comparable to that of low-chloride solutions.

Effect of 0.9% NaCl compared to plasma-lyte on biomarkers of kidney injury, sodium excretion and tubular transport proteins in patients undergoing primary uncemented hip replacement - a randomized trial

Background

Isotonic saline (IS) is widely used to secure perioperative cardiovascular stability. However, the high amount of chloride in IS can induce hyperchloremic acidosis. Therefore, IS is suspected to increase the risk of acute kidney injury (AKI). Biomarkers may have potential as indicators.

Methods

In a double-blinded, placebo-controlled study, 38 patients undergoing primary uncemented hip replacement were randomized to IS or PlasmaLyte (PL). Infusion was given during surgery as 15 ml/kg the first hour and 5 ml/kg the following two hours. Urinary samples were collected upon admission and the day after surgery. As surgery was initiated, urine was collected over the course of 4 h. Hereafter, another urine collection proceeded until the morning. Urine was analyzed for markers of AKI neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Arterious and venous blood samples for measurements of pH and plasma electrolytes including chloride (p-Cl) were collected as surgery was initiated, at the end of surgery and the following morning.

Results

IS induced an increase in p-Cl (111 ± 2 mmol/L after IS and 108 ± 3 after PL, p = 0.004) and a decrease in pH (7.39 ± 0.02 after IS and 7.43 ± 0.03 after PL, p = 0.001). Urinary NGAL excretion increased in both groups (ΔNGAL: 5.5 [4.1; 11.7] μg/mmol creatinine p = 0.004 after IS vs. 5.5 [2.1;9.4] μg/mmol creatinine after PL, p < 0.001). No difference was found between the groups (p = 0.839). Similarly, urinary KIM-1 excretion increased in both groups (ΔKIM-1: IS 115.8 [74.1; 156.2] ng/mmol creatinine, p < 0.001 vs. PL 152.4 [120.1; 307.9] ng/mmol creatinine, p < 0.001). No difference between the groups (p = 0.064).

FE_Na increased (1.08 ± 0.52% after IS and 1.66 ± 1.15% after PL, p = 0.032). ENaC excretion was different within groups (p = 0.019).

Conclusion

A significantly higher plasma chloride and a lower pH was present in the group receiving isotonic saline. However, u-NGAL and u-KIM-1 increased significantly in both groups after surgery despite absence of changes in creatinine. These results indicate that surgery induced subclinical kidney injury. Also, the IS group had a delayed sodium excretion as compared to the PL group which may indicate that IS affects renal sodium excretion differently from PL.

Trial registration

ClinicalTrials.gov Identifier: NCT02528448, 19/08/2015

Low- versus High-Chloride Content Intravenous Solutions for Perioperative Patients: A Systematic Review and Meta-Analysis

Background

Studies have shown complications of normal saline infusion because of its high-chloride content. Therefore, in the present study, we aimed to explore whether the use of low- versus high-chloride solutions benefited the unselected and specifically perioperative patients and was associated with different outcomes.

Methods

Studies on the use of low- versus high-chloride content intravenous solutions for perioperative patients, published up to July 15, 2019, were systematically reviewed, and primary and secondary outcomes were quantitatively summarized.

Results

A total of 14 eligible randomized controlled trials with 943 perioperative patients were included. Five studies reported all-cause mortality, and eight studies provided detailed data on renal replacement therapy (RRT). The pooled result suggested no statistically significant difference in the effect of low- versus high-chloride solutions on all-cause mortality (risk ratio (RR) = 1.39; 95%confidence interval (CI) = 0.23–8.26) and RRT (RR = 1.05; 95%CI = 0.63–1.76). The pooled results on acute kidney injury (AKI) and the use of allogenic blood transfusion (P > 0.05) were similar.

Conclusion

Among specific perioperative patients, the use of low- versus high-chloride content intravenous solutions did not reduce the all-cause mortality, risk of severe AKI, or rate of RRT use. Further large randomized clinical trials are needed to confirm or refute this finding.

Intravenous Fluid of Choice in Major Abdominal Surgery: A Systematic Review

Background

Intravenous fluid therapy plays a role in maintaining the hemodynamic status for tissue perfusion and electrolyte hemostasis during surgery. Recent trials in critically ill patients reported serious side effects of some types of fluids. Since the most suitable type of fluid is debatable, a consensus in perioperative patients has not been reached.

Method

We performed a systematic review of randomized control trials (RCTs) that compared two or more types of fluids in major abdominal surgery. The outcomes were related to bleeding, hemodynamic status, length of hospital stay, and complications, such as kidney injury, electrolyte abnormality, major cardiac adverse event, nausea, vomiting, and mortality. A literature search was performed using Medline and EMBASE up to December 2019. The data were pooled to investigate the effect of fluid on macrocirculation and intravascular volume effect.

Results

Forty-three RCTs were included. Eighteen fluids were compared: nine were crystalloids and nine were colloids. The results were categorized into macrocirculation and intravascular volume effect, microcirculation, anti-inflammatory parameters, vascular permeability, renal function (colloids), renal function and electrolytes (crystalloids), coagulation and bleeding, return of bowel function, and postoperative nausea vomiting (PONV). We found that no specific type of fluid led to mortality and every type of colloid was equivalent in volume expansion and did not cause kidney injury. However, hydroxyethyl starch and dextran may lead to increased bleeding. Normal saline can cause kidney injury which can lead to renal replacement therapy, and dextrose fluid can decrease PONV.

Conclusion

In our opinion, it is safe to give a balanced crystalloid as the maintenance fluid and give a colloid, such as HES130/0.4, 4% gelatin, or human albumin, as a volume expander.

Managing Chloride and Bicarbonate in the Prevention and Treatment of Acute Kidney Injury

Intravenous crystalloid therapy is one of the most ubiquitous aspects of hospital and critical care medicine. In recent years, there has been increasing focus on the electrolyte composition, and particularly chloride content, of crystalloid solutions. This has led to increasing clinical adoption of balanced solutions, containing substrates for bicarbonate generation and consequently a lower chloride content, in place of 0.9% saline. In this article we review the physiochemical rationale for avoidance of 0.9% saline and the effects of hyperchloremic acidosis on renal physiology. Finally, we review the current evidence and rationale for use of balanced solutions greater than 0.9% saline in acutely ill patients in a variety of clinical settings, as well as considering the role for sodium bicarbonate in preventing or correcting metabolic acidosis. In conclusion, there is a strong physiological rationale for avoidance of iatrogenic hyperchloremic acidosis from 0.9% saline administration in acutely unwell patients and an association with adverse renal outcomes in several studies. However, evidence from large definitive multicenter randomized trials is not yet available to establish the dose-relationship between 0.9% saline administration and potential harm and inform us if some 0.9% saline use is acceptable or if any exposure confers harm.

Acid-Base Balance Disorders During Kidney Preservation in Cold Ischemia

BACKGROUND

Acid-base balance disorders are a crucial element of ischemia-reperfusion injury during organ transplantation. Hypoxia during organ procurement and storage cause cellular homeostasis imbalance with impact on further graft function. Acidosis in preserved kidney caused by lactate accumulation may have an important role as a common denominator of various pathways leading to cellular damage.

METHODS

Our trial sought to answer questions regarding a range of pH alterations in the kidney before the transplantation, their potential cause, and how this may affect further outcome of the kidney transplantation procedure. Perfusion fluid for pH analysis was obtained from perfusion pump (PP) or through kidney flushing at the end of preservation depending on the storage method.

RESULTS

A total of 66 sample results were collated with the data from the transplant registry, hospitalization, and outpatient department. Statistical analysis was conducted linking pH results with factors related to donor, recipient, preservation, and outcome according to designed schematics. Mean perfusate pH was significantly lower in simple hypothermia (SH) vs the PP storage group (6.77 vs 7.11; P < .001). All samples of perfusate pH in the SH group were below physiological values (<7.35), and in 10% of samples in the SH group, pH >7.00.

CONCLUSIONS

We concluded that kidney storage in cold ischemia is associated with organ acidosis independent of preservation method and that SH is correlated with significantly bigger acidosis than storage in PP, which is an important procedure removing an excessive amount of hydrogen ions from kidney microcirculation, decreasing cell damage.

Association between perioperative normal saline and delayed graft function in deceased-donor kidney transplantation: a retrospective observational study

PURPOSE

Isotonic 0.9% sodium chloride (normal saline; NS) solution use is common, but its high chloride content has been shown to contribute to acid-base disturbances and acute kidney injury (AKI). As kidney transplant recipients are at high risk of postoperative AKI and renal replacement therapy, we aimed to evaluate the impact of perioperative NS administration on graft function after kidney transplantation.

METHODS

All adult patients undergoing deceased-donor kidney transplantation between January 2010 and December 2014 at the Rennes University Hospital were included. Logistic regression models were constructed to evaluate the association of hyperchloremia and hyperchloremic acidosis on delayed graft function (DGF), defined as the need for renal replacement therapy within the first week after transplantation.

RESULTS

Three hundred and fifty-nine patients were included, 20% developed DGF. The mean (standard deviation) volume of NS infused in the operating room and in the standard postoperative intensive care unit stay was 4,832 (2,242) mL. In the first 24 postoperative hours, 11% of patients developed hyperchloremia and 11% developed hyperchloremic acidosis. These outcomes were not associated with significantly higher total volumes of NS administration or with DGF. In contrast, multivariable analysis showed that cold ischemia time, donor terminal creatinine, and perioperative NS volume were all independent predictors of DGF.

CONCLUSION

Perioperative NS infusion volume was associated with DGF in deceased-donor kidney transplant recipients. Conversely, postoperative hyperchloremia and hyperchloremic acidosis were not associated with an increased risk of DGF, suggesting other mechanisms than a chloride effect.

Balanced Crystalloid Solutions

Intravenous fluid therapy is the most common intervention received by acutely ill patients. Historically, saline (0.9% sodium chloride) has been the most frequently administered intravenous fluid, especially in North America. Balanced crystalloid solutions (e.g., lactated Ringer's, Plasma-Lyte) are an increasingly used alternative to saline. Balanced crystalloids have a sodium, potassium, and chloride content closer to that of extracellular fluid and, when given intravenously, have fewer adverse effects on acid-base balance. Preclinical research has demonstrated that saline may cause hyperchloremic metabolic acidosis, inflammation, hypotension, acute kidney injury, and death. Studies of patients and healthy human volunteers suggest that even relatively small volumes of saline may exert physiological effects. Randomized trials in the operating room have demonstrated that using balanced crystalloids rather than saline prevents the development of hyperchloremic metabolic acidosis and may reduce the need for vasopressors. Observational studies among critically ill adults have associated receipt of balanced crystalloids with lower rates of complications, including acute kidney injury and death. Most recently, large randomized trials among critically ill adults have examined whether balanced crystalloids result in less death or severe renal dysfunction than saline. Although some of these trials are still ongoing, a growing body of evidence raises fundamental concerns regarding saline as the primary intravenous crystalloid for critically ill adults and highlights fundamental unanswered questions for future research about fluid therapy in critical illness.

Low- Versus High-Chloride Content Intravenous Solutions for Critically Ill and Perioperative Adult Patients: A Systematic Review and Meta-analysis

BACKGROUND

To assess whether use of low-chloride solutions in unselected critically ill or perioperative adult patients for maintenance or resuscitation reduces mortality and renal replacement therapy (RRT) use when compared to high-chloride fluids.

METHODS

Systematic review and meta-analysis with random-effects inverse variance model. PubMed, Cochrane library, EMBASE, LILACS, and Web of Science were searched from inception to October 2016. Published and unpublished randomized controlled trials in any language that enrolled critically ill and/or perioperative adult patients and compared a low- to a highchloride solution for volume maintenance or resuscitation. The primary outcomes were mortality and RRT use. We conducted trial sequential analyses and assessed risk of bias of individual trials and the overall quality of evidence. Fifteen trials with 4067 patients, most at low risk of bias, were identified. Of those, only 11 and 10 trials had data on mortality and RRT use, respectively. A total of 3710 patients were included in the mortality analysis and 3724 in the RRT analysis.

RESULTS

No statistically significant impact on mortality (odds ratio, 0.90; 95% confidence interval, 0.69-1.17; P = .44; I = 0%) or RRT use (odds ratio, 1.12; 95% confidence interval, 0.80-1.58; P = .52; I = 0%) was found. Overall quality of evidence was low for both primary outcomes. Trial sequential analyses highlighted that the sample size needed was much larger than that available for properly powered outcome assessment.

CONCLUSIONS

The current evidence on low- versus high-chloride solutions for unselected critically ill or perioperative adult patients demonstrates no benefit, but suffers from considerable imprecision. We noted a limited exposure volume for study fluids and a relatively low risk of the populations in each study. Together with the relatively small pooled sample size, these data leave us underpowered to detect potentially important differences. Results from well-conducted, adequately powered randomized controlled trials examining sufficiently large fluid exposure are necessary.

Perioperative administration of buffered versus non-buffered crystalloid intravenous fluid to improve outcomes following adult surgical procedures: a Cochrane systematic review

Background

Buffered intravenous fluid preparations contain substrates to maintain acid-base status. The objective of this systematic review was to compare the effects of buffered and non-buffered fluids administered during the perioperative period on clinical and biochemical outcomes.

Methods

We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library until May 2017 and included all randomised controlled trials that evaluated buffered versus non-buffered fluids, whether crystalloid or colloid, administered to surgical patients. We assessed the selected studies for risk of bias and graded the level of evidence in accordance with Cochrane recommendations.

Results

We identified 19 publications of 18 randomised controlled trials, totalling 1096 participants. Mean difference (MD) in postoperative pH was 0.05 units lower immediately following surgery in the non-buffered group (12 studies of 720 participants; 95% confidence interval (CI) 0.04 to 0.07; I² = 61%). This difference did not persist on postoperative day 1. Serum chloride concentration was higher in the non-buffered group at the end of surgery (10 trials of 530 participants; MD 6.77 mmol/L, 95% CI 3.38 to 10.17). This effect persisted until postoperative day 1 (5 trials of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). Quality of this evidence was moderate. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Outcome data was variably reported at disparate time points and with heterogeneous patient groups. Consequently, the effect size and overall confidence interval was reduced, despite the relatively low inherent risk of bias. There was insufficient evidence on the effect of fluid composition on mortality and organ dysfunction. Confidence intervals of this outcome were wide and the quality of evidence was low (3 trials of 276 participants for mortality; odds ratio (OR) 1.85, 95% CI 0.37 to 9.33; I² = 0%).

Conclusions

Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Buffered fluid may have biochemical benefits, including a significant reduction in postoperative hyperchloraemia and metabolic acidosis.

Electronic supplementary material

The online version of this article (10.1186/s13741-018-0108-5) contains supplementary material, which is available to authorized users.

"I don't get no respect": the role of chloride in acute kidney injury

Acute kidney injury (AKI) is a major public health problem that complicates 10-40% of hospital admissions. Importantly, AKI is independently associated with increased risk of progression to chronic kidney disease, end-stage renal disease, cardiovascular events, and increased risk of in-hospital and long-term mortality. The chloride content of intravenous fluid has garnered much attention over the last decade, as well as its association with excess use and adverse outcomes, including AKI. Numerous studies show that changes in serum chloride concentration, independent of serum sodium and bicarbonate, are associated with increased risk of AKI, morbidity, and mortality. This comprehensive review details the complex renal physiology regarding the role of chloride in regulating renal blood flow, glomerular filtration rate, tubuloglomerular feedback, and tubular injury, as well as the findings of clinical research related to the chloride content of intravenous fluids, changes in serum chloride concentration, and AKI. Chloride is underappreciated in both physiology and pathophysiology. Although the exact mechanism is debated, avoidance of excessive chloride administration is a reasonable treatment option for all patients and especially in those at risk for AKI. Therefore, high-risk patients and those with "incipient" AKI should receive balanced solutions rather than normal saline to minimize the risk of AKI.

The effects of Plasma-Lyte 148 solution on blood coagulation: an in-vitro, volunteer study using rotational thromboelastometry

The current study aimed to measure the effects of Plasma-Lyte 148 solution on the blood coagulation profile according to the hemodilution level using rotational thromboelastometry (ROTEM) tests. Venous blood was collected from 12 healthy volunteers and divided into four specimen bottles, which were diluted at different levels with Plasma-Lyte 148 (0, 20, 40, and 60%). Following this, ROTEM tests were performed on the study samples. We found that as the hemodilution level increased, the ROTEM values showed a hypocoagulable pattern. The change rate of the maximum clot firmness (MCF) of INTEM was greater in the 40 (P = 0.015) and 60% (P < 0.001) dilutions than it was in the 20% dilution. Greater lengthening of the clot formation time of EXTEM was observed in the 60% dilution than it was in the 20% dilution (P < 0.001). The alpha-angle of EXTEM showed a greater decrease in the 60% dilution than it did in the 20% dilution (P < 0.001). A larger change rate of the MCF of EXTEM was observed in the 40 (P = 0.003) and 60% (P < 0.001) dilutions than it was in the 20% dilution. A greater decrease in the MCF of FIBTEM was identified in the 40 (P = 0.009) and 60% (P < 0.001) dilutions than in the 20% dilution. All coagulation pathways exhibited hypocoagulable patterns as the hemodilution level increased. However, most of the mean values of ROTEM parameters were within the normal reference range, except for those of the 60% dilution.

Normal saline versus Normosol™-R in sepsis resuscitation: A retrospective cohort study

Objective

To determine the effect of Normosol™-R as compared to normal saline on the outcomes of acute kidney injury and the need for renal replacement therapy in the resuscitation phase of sepsis.

Design

Our study is a retrospective before-and-after cohort study.

Setting

The study occurred at a 700-bed tertiary academic level 1-trauma center.

Patients

A total of 1218 patients were enrolled through emergency department admissions. The normal saline (before) cohort was defined as the dates between 1 March and 30 September 2014 and the Normosol™-R (after) cohort was assessed from 1 March to 30 September 2015.

Interventions

None.

Measurements and main results

Intravenous fluid volumes received during the first 24 h, 72 h, and total hospital stays were compared. Sodium, chloride, potassium, and bicarbonate levels at 72 h were also compared. The medical coded diagnosis of acute kidney failure, need for renal replacement therapy, hospital LOS, ICU admission, ICU LOS, in-hospital mortality, and need for mechanical ventilation were all compared. There was no significant difference in intravenous fluid volumes between groups. Regression modelling controlling for baseline characteristics and 24-h fluid intake volume found no differences between groups for the primary outcomes of acute kidney injury (P = 0.99) and renal replacement therapy (P = 0.88). Patients in the Normosol™-R cohort were found to have a lower rate of hyperchloremia at 72 h post-admission (28% vs. 13%, P < 0.0001). There was a trend toward a decrease in the hospital and ICU LOS in the Normosol™-R cohort; however, the data were not statistically significant.

Conclusions

This study was unable to detect any difference in outcomes between sepsis patients who received intravenous fluid resuscitation with either a balanced crystalloid (Normosol™-R) or normal saline, except for a decreased rate of hyperchloremia.

Allowable warm ischemic time and morphological and biochemical changes in uterine ischemia/reperfusion injury in cynomolgus macaque: a basic study for uterus transplantation

STUDY QUESTION

How long is the allowable warm ischemic time of the uterus and what morphological and biochemical changes are caused by uterine ischemia/reperfusion injury in cynomolgus macaques?

SUMMARY ANSWER

Warm ischemia in the uterus of cynomolgus macaques is tolerated for up to 4 h and reperfusion after uterine ischemia caused no further morphological and biochemical changes.

WHAT IS KNOWN ALREADY

Uterus transplantation is a potential option for women with uterine factor infertility. The allowable warm ischemic time and ischemia/reperfusion injury of the uterus in humans and non-human primates is unknown.

STUDY DESIGN, SIZE, DURATION

This experimental study included 18 female cynomolgus macaques with periodic menstruation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Animals were divided into six groups of three monkeys each: a control group and groups with uterine ischemia for 0.5, 1, 2, 4 and 8 h. Biopsies of uterine tissues were performed before blood flow blockage, after each blockage time, and after reperfusion for 3 h. Blood sampling was performed after each blockage time, and after reperfusion for 5, 15 and 30 min for measurement of biochemical data. Resumption of menstruation was monitored after the surgical procedure. Morphological, physiological and biochemical changes after ischemia and reperfusion were evaluated.

MAIN RESULTS AND THE ROLE OF CHANCE

Mild muscle degeneration and zonal degeneration were observed in all animals subjected to warm ischemia for 4 or 8 h, but there were no marked differences in the appearance of specimens immediately after ischemia and after reperfusion for 3 h in animals subjected to 4 or 8 h of warm ischemia. There were no significant changes in any biochemical parameters at any time point in each group. Periodical menstruation resumed in all animals with warm ischemia up to 4 h, but did not recover in animals with warm ischemia for 8 h with atrophic uteri.

LIMITATIONS, REASON FOR CAUTION

Warm ischemia in actual transplantation was not exactly mimicked in this study because uteri were not perfused, cooled, transplanted or reanastomosed with vessels. Results in non-human primates cannot always be extrapolated to humans.

WIDER IMPLICATIONS OF THE FINDINGS

The findings suggest that the tolerable warm ischemia time in the uterus is expected to be longer than that in other vital organs.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number 26713050. None of the authors has a conflict of interest to declare.

Acid/base alterations during major abdominal surgery: 6% hydroxyethyl starch infusion versus 5% albumin

BACKGROUND

To compare the effects of intraoperative infusions of balanced electrolyte solution (BES)-based hydroxyethyl starch (HES) and saline-based albumin on metabolic acidosis and acid/base changes during major abdominal surgery conducted using Stewart's approach.

METHODS

Forty patients, aged 20-65 years, undergoing major abdominal surgery, were randomly assigned to the HES group (n = 20; received 500 ml of BES-based 6% HES 130/0.4) or the albumin group (n = 20; received 500 ml of normal saline-based 5% albumin). Acid-base parameters were measured and calculated using results obtained from arterial blood samples taken after anesthesia induction (T1), 2 hours after surgery commencement (T2), immediately after surgery (T3), and 1 hour after arriving at a postanesthetic care unit (T4).

RESULTS

Arterial pH in the HES group was significantly higher than that in the albumin group at T3 (7.40 ± 0.04 vs. 7.38 ± 0.04, P = 0.043), and pH values exhibited significant intergroup difference over time (P = 0.002). Arterial pH was significantly lower at T3 and T4 in the HES group and at T2, T3, and T4 in the albumin group than at T1. Apparent strong ion difference (SIDa) was significantly lower at T2, T3, and T4 than at T1 in both groups. Total plasma weak nonvolatile acid (ATOT) was significantly lower in the HES group than in the albumin group at T2, T3 and T4 and exhibited a significant intergroup difference over time (P < 0.001).

CONCLUSIONS

BES-based 6% HES infusion was associated with lower arterial pH values at the end of surgery than saline-based 5% albumin infusion, but neither colloid caused clinically significant metabolic acidosis (defined as an arterial pH < 7.35).

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.

Balanced crystalloids vs 0.9% saline for adult patients undergoing non-renal surgery: A meta-analysis

BACKGROUND

Fluid maintenance and resuscitation is an important strategy during major surgeries. There has been a debate on the choice of crystalloids over the past decades. 0.9% saline (normal saline) is more likely to cause hyperchloremic acidosis when compared to balanced crystalloids with low chloride content. Meta-analyses comparing these two kinds of crystalloids have been performed in renal transplantations. We aim to compare the safety of balanced crystalloids to normal saline among adult patients undergoing non-renal surgery.

METHODS

Relevant articles were searched through PubMed, Embase and the Cochrane Library. Nine randomized controlled trials (including 871 participants) comparing balanced crystalloids to normal saline on adult patients undergoing non-renal surgery were finally included. Possible effects were calculated using meta-analysis.

RESULTS

Patients in the normal saline group had significantly lower postoperative pH (MD: 0.05; 95% CI: 0.04-0.06; p < .001; I² = 82%) and base excess (MD: 2.04; 95% CI: 1.44-2.65; p < .001; I² = 87%). The postoperative serum chloride level was significantly higher in the normal saline group (MD: -4.79; 95% CI: -8.13∼-1.45; p = .005; I² = 95%).

CONCLUSION

Comparing to normal saline, balanced crystalloids are more beneficial in keeping postoperative electrolytes and acid-base balance among adult patients undergoing non-renal surgery. Future researches should pay more attention to meaningful clinical outcomes concerning the safety of balanced crystalloids and normal saline.

Perioperative administration of buffered versus non-buffered crystalloid intravenous fluid to improve outcomes following adult surgical procedures

BACKGROUND

Perioperative fluid strategies influence clinical outcomes following major surgery. Many intravenous fluid preparations are based on simple solutions, such as normal saline, that feature an electrolyte composition that differs from that of physiological plasma. Buffered fluids have a theoretical advantage of containing a substrate that acts to maintain the body's acid-base status - typically a bicarbonate or a bicarbonate precursor such as maleate, gluconate, lactate, or acetate. Buffered fluids also provide additional electrolytes, including potassium, magnesium, and calcium, more closely matching the electrolyte balance of plasma. The putative benefits of buffered fluids have been compared with those of non-buffered fluids in the context of clinical studies conducted during the perioperative period. This review was published in 2012, and was updated in 2017.

OBJECTIVES

To review effects of perioperative intravenous administration of buffered versus non-buffered fluids for plasma volume expansion or maintenance, or both, on clinical outcomes in adults undergoing all types of surgery.

SEARCH METHODS

We electronically searched the Clinicaltrials.gov major trials registry, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 6) in the Cochrane Library, MEDLINE (1966 to June 2016), Embase (1980 to June 2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to June 2016). We handsearched conference abstracts and, when possible, contacted leaders in the field. We reran the search in May 2017. We added one potential new study of interest to the list of 'Studies awaiting classification' and will incorporate this trial into formal review findings when we prepare the review update.

SELECTION CRITERIA

Only randomized controlled trials that compared buffered versus non-buffered intravenous fluids for surgical patients were eligible for inclusion. We excluded other forms of comparison such as crystalloids versus colloids and colloids versus different colloids.

DATA COLLECTION AND ANALYSIS

Two review authors screened references for eligibility, extracted data, and assessed risks of bias. We resolved disagreements by discussion and consensus, in collaboration with a third review author. We contacted trial authors to request additional information when appropriate. We presented pooled estimates for dichotomous outcomes as odds ratios (ORs) and for continuous outcomes as mean differences (MDs), with 95% confidence intervals (CIs). We analysed data via Review Manager 5.3 using fixed-effect models, and when heterogeneity was high (I² > 40%), we used random-effects models.

MAIN RESULTS

This review includes, in total, 19 publications of 18 randomized controlled trials with a total of 1096 participants. We incorporated five of those 19 studies (330 participants) after the June 2016 update. Outcome measures in the included studies were thematically similar, covering perioperative electrolyte status, renal function, and acid-base status; however, we found significant clinical and statistical heterogeneity among the included studies. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Trial authors variably reported outcome data at disparate time points and with heterogeneous patient groups. Consequently, many outcome measures are reported in small group sizes, reducing overall confidence in effect size, despite relatively low inherent bias in the included studies. Several studies reported orphan outcome measures. We did not include in the results of this review one large, ongoing study of saline versus Ringer's solution.We found insufficient evidence on effects of fluid therapies on mortality and postoperative organ dysfunction (defined as renal insufficiency leading to renal replacement therapy); confidence intervals were wide and included both clinically relevant benefit and harm: mortality (Peto OR 1.85, 95% CI 0.37 to 9.33; I² = 0%; 3 trials, 6 deaths, 276 participants; low-quality evidence); renal insufficiency (OR 0.82, 95% CI 0.34 to 1.98; I² = 0%; 4 trials, 22 events, 276 participants; low-quality evidence).We noted several metabolic differences, including a difference in postoperative pH measured at end of surgery of 0.05 units - lower in the non-buffered fluid group (12 studies with a total of 720 participants; 95% CI 0.04 to 0.07; I² = 61%). However, this difference was not maintained on postoperative day one. We rated the quality of evidence for this outcome as moderate. We observed a higher postoperative serum chloride level immediately after operation, with use of non-buffered fluids reported in 10 studies with a total of 530 participants (MD 6.77 mmol/L, 95% CI 3.38 to 10.17), and this difference persisted until day one postoperatively (five studies with a total of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). We rated the quality of evidence for this outcome as moderate.

AUTHORS' CONCLUSIONS

Current evidence is insufficient to show effects of perioperative administration of buffered versus non-buffered crystalloid fluids on mortality and organ system function in adult patients following surgery. Benefits of buffered fluid were measurable in biochemical terms, particularly a significant reduction in postoperative hyperchloraemia and metabolic acidosis. Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Larger studies are needed to assess these relevant clinical outcomes.

Balanced versus isotonic saline resuscitation-a systematic review and meta-analysis of randomized controlled trials in operation rooms and intensive care units

BACKGROUND

Fluid resuscitation is the cornerstone in treatment of shock, and intravenous fluid administration is the most frequent intervention in operation rooms and intensive care units (ICUs). The composition of fluids used for fluid resuscitation gained interest over the past decade, with recent focus on whether balanced solutions should be preferred over isotonic saline.

METHODS

Systematic review and meta-analysis of randomized controlled trials (RCTs) comparing fluid resuscitation with a balanced solution versus isotonic saline in adult patients in operation room or ICUs. Primary outcome was in-hospital mortality, secondary outcomes included occurrence of acute kidney injury (AKI) and need for renal replacement therapy (RRT).

RESULTS

The search identified 11 RCTs involving 2,703 patients; 8 trials were conducted in operation room and 3 in ICU. In-hospital mortality, as well as the occurrence of AKI and need for RRT was not different between resuscitation with balanced solutions versus isotonic saline, neither in operation room nor in ICU patients. Serum chloride levels, but not arterial pH, were significantly lower in patients resuscitated with balanced solutions.

CONCLUSIONS

Currently evidence insufficiently supports the use of balanced over isotonic saline for fluid resuscitation to improve outcome of operation room and ICU patients.

Balanced crystalloids for septic shock resuscitation

Timely fluid administration is crucial to maintain tissue perfusion in septic shock patients. However, the question concerning which fluid should be used for septic shock resuscitation remains a matter of debate. A growing body of evidence suggests that the type, amount and timing of fluid administration during the course of sepsis may affect patient outcomes. Crystalloids have been recommended as the first-line fluids for septic shock resuscitation. Nevertheless, given the inconclusive nature of the available literature, no definitive recommendations about the most appropriate crystalloid solution can be made. Resuscitation of septic and non-septic critically ill patients with unbalanced crystalloids, mainly 0.9% saline, has been associated with a higher incidence of acid-base balance and electrolyte disorders and might be associated with a higher incidence of acute kidney injury. This can result in greater demand for renal replacement therapy and increased mortality. Balanced crystalloids have been proposed as an alternative to unbalanced solutions in order to mitigate their detrimental effects. Nevertheless, the safety and effectiveness of balanced crystalloids for septic shock resuscitation need to be further addressed in a well-designed, multicenter, pragmatic, randomized controlled trial.

Plasma-Lyte 148: A clinical review

AIM

To outline the physiochemical properties and specific clinical uses of Plasma-Lyte 148 as choice of solution for fluid intervention in critical illness, surgery and perioperative medicine.

METHODS

We performed an electronic literature search from Medline and PubMed (via Ovid), anesthesia and pharmacology textbooks, and online sources including studies that compared Plasma-Lyte 148 to other crystalloid solutions. The following keywords were used: “surgery”, “anaesthesia”, “anesthesia”, “anesthesiology”, “anaesthesiology”, “fluids”, “fluid therapy”, “crystalloid”, “saline”, “plasma-Lyte”, “plasmalyte”, “hartmann’s”, “ringers”“acetate”, “gluconate”, “malate”, “lactate”. All relevant articles were accessed in full. We summarized the data and reported the data in tables and text.

RESULTS

We retrieved 104 articles relevant to the choice of Plasma-Lyte 148 for fluid intervention in critical illness, surgery and perioperative medicine. We analyzed the data and reported the results in tables and text.

CONCLUSION

Plasma-Lyte 148 is an isotonic, buffered intravenous crystalloid solution with a physiochemical composition that closely reflects human plasma. Emerging data supports the use of buffered crystalloid solutions in preference to saline in improving physicochemical outcomes. Further large randomized controlled trials assessing the comparative effectiveness of Plasma-Lyte 148 and other crystalloid solutions in measuring clinically important outcomes such as morbidity and mortality are needed.

Normal saline versus lower-chloride solutions for kidney transplantation

BACKGROUND

The ideal intravenous fluid for kidney transplantation has not been defined, despite the common use of normal saline during the peri-operative period. The high chloride content of normal saline is associated with an increased risk of hyperchloraemic metabolic acidosis, which may in turn increase the risk of hyperkalaemia and delayed graft function. Balanced electrolyte solutions have a lower chloride content which may decrease this risk and avoid the need for dialysis due to hyperkalaemia in the immediate post-transplant period. Randomised controlled trials (RCTs) addressing this issue have used biochemical outcomes to compare fluids and have been underpowered to address patient-centred outcomes such as delayed graft function.

OBJECTIVES

To examine the effect of lower-chloride solutions versus normal saline on delayed graft function, hyperkalaemia and acid-base status in kidney transplant recipients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant's Specialised Register to 26 November 2015 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

RCTs of kidney transplant recipients that compared peri-operative intravenous lower-chloride solutions to normal saline were included.

DATA COLLECTION AND ANALYSIS

Two independent investigators assessed studies for eligibility and risk of bias. Data from individual studies were extracted using standardised forms and pooled according to a published protocol. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

Six studies (477 participants) were included in the review. All participants were adult kidney transplant recipients and 70% of participants underwent live-donor kidney transplantation. The overall risk of bias was low for selection bias and unclear for remaining domains. There was no difference in the risk of delayed graft function (3 studies, 298 participants: RR 1.03, 95% CI 0.62 to 1.70) or hyperkalaemia (2 studies, 199 participants: RR 0.48, 95% CI 0.04 to 6.10) for participants who received balanced electrolyte solutions compared to normal saline. Intraoperative balanced electrolyte solutions compared to normal saline were associated with higher blood pH (3 studies, 193 participants: MD 0.07, 95% CI 0.05 to 0.09), higher serum bicarbonate (3 studies, 215 participants: MD 3.02 mEq/L, 95% CI 2.00 to 4.05) and lower serum chloride (3 studies, 215 participants: MD -9.93 mmol/L, 95% CI -19.96 to 0.11). There were four cases of graft loss in the normal saline group and one in the balanced electrolyte solution group, and four cases of acute rejection in the normal saline group compared to two cases in the balanced electrolyte solution group.

AUTHORS' CONCLUSIONS

Balanced electrolyte solutions are associated with less hyperchloraemic metabolic acidosis compared to normal saline, however it remains uncertain whether lower-chloride solutions lead to improved graft outcomes compared to normal saline.

Acetate-buffered crystalloid fluids: Current knowledge, a systematic review

INTRODUCTION

The concept of fluid resuscitation with balanced solutions containing acetate is relatively new. The knowledge about acetate mostly originates from nephrological research, as acetate was primarily used as a dialysis buffer where much higher doses of acetate are infused. The aim of this review is to give an overview of the advantages and disadvantages of an acetate-buffered crystalloid fluid when compared with other crystalloid infusates.

METHODS

We report trials with the primary object of comparing an acetate-buffered infusion solute to another crystalloid infusate. A systematic literature search of MEDLINE and the Cochrane Controlled Clinical trials register was conducted to identify suitable studies.

RESULTS

The search strategy used produced 1205 potential titles. After eliminating doubles, 312 titles and abstracts were screened, and 31 references were retrieved for full-text analysis. A total of 27 scientific studies were included in the study.

CONCLUSION

Acetate-buffered crystalloid solutes do have a favorable influence on microcirculation. To what extent the acetate-buffered crystalloids influence kidney function is controversially discussed and not yet clear. Metabolic alkalosis did not occur in a single study in humans after an acetate-buffered infusate; potassium levels stayed stable in all studies. Cardiac output and contractility seem to be positively influenced; nonetheless, data on maintenance of a target blood pressure remain inconclusive. Whether acetate-buffered crystalloid fluids lead to lower rates of acute kidney injury and increased survival when compared with normal saline is yet unclear and may depend on the amount of fluid administered.

Impact of common crystalloid solutions on resuscitation markers following Class I hemorrhage: A randomized control trial

BACKGROUND

Resuscitation after hemorrhage with crystalloid solutions can lead to marked acidosis and iatrogenically worsen the lethal triad. The effect of differing solutions on base deficit and lactate has been sparsely prospectively studied in humans. We sought to quantify the effect of normal saline (NS) and lactated Ringer's (LR) resuscitation in voluntary blood donors as a model for Class I hemorrhage.

METHODS

A prospective randomized control trial was conducted in conjunction with blood drives. Donors were randomized to receive no intravenous fluid (noIVF), 2-L NS, or 2-L LR after blood donation of 500 mL. Lactate and base deficit were measured before and after fluid administration using an iSTAT. The mean laboratory values were compared between groups first using a global test followed by pairwise testing between groups using the Wilcoxon rank-sum and Kruskal-Wallis tests. The Bonferroni correction was used and a statistical significance of p < 0.0167 was set.

RESULTS

A total of 157 patients completed the study. The mean (SD) age was 39.2 (12.7), and 65.0% were female. Patients in each group lost equivalent amounts of total blood volume, and a similar amount was replaced in the crystalloid group (p > 0.0167). Donors had comparable increases in lactate and base deficit after donation regardless of the group (p > 0.0167). After resuscitation with 2-L crystalloid, the lactate level increased higher in the LR group than in the noIVF or the NS group (1.36 mmol/L vs. 1.00 mmol/L vs. 1.54 mmol/L, p < 0.0001). In addition, the resuscitation base deficit increased in the NS group more than in the noIVF or LR group (-0.65 vs. -3.06 vs. -0.34, p < 0.0001).

CONCLUSION

This study is one of the first human studies to prospectively demonstrate quantifiable differences in base deficit and lactate by type of crystalloid resuscitation. LR resuscitation elevated lactate levels, and NS negatively affected the base deficit. These findings are critical to the interpretation of trauma patient resuscitation with crystalloid solutions.

LEVEL OF EVIDENCE

Therapeutic study, level II.

Crystalloid fluid therapy

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

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.

What is the ideal crystalloid?

PURPOSE OF REVIEW

We discuss the importance of the composition of intravenous crystalloid solutions. On the basis of current physiologic principles, evidence from basic science and clinical experiments, recent observational studies, and clinical trials, we conclude that the 'ideal crystalloid' depends on clinical context. We make recommendations on solutions that may be used during critical illness, major surgery, and certain clinical situations.

RECENT FINDINGS

The routine use of solutions with a supraphysiologic chloride content and a low strong ion difference (SID), such as isotonic saline solution, may be associated with adverse outcomes, especially among critically ill patients. On the contrary, solutions with a physiologic chloride content and a 'balanced' electrolyte composition (SID closer to plasma) may improve the likelihood of survival. The distribution of different types of crystalloids across traditional 'body compartments' is a function of osmolality of the fluid infused relative to plasma, integrity of the glycocalyx, and the hemodynamic/'volume' state of the patient. During critical illness, the routine administration of colloids may offer no clinical benefits compared with the use of crystalloids.

SUMMARY

Crystalloids, like other types of intravenous fluids, are drugs with important effects on clinical outcomes that may be mediated by osmolality, chloride content, and SID.

Fluid management in abdominal surgery: what, when, and when not to administer

The entire team (including anesthesiologists, surgeons, and intensive care physicians) must work together (before, during, and after abdominal surgery) to determine the optimal amount (quantity) and type (quality) of fluid necessary in the perioperative period. The authors present an overview of the basic principles that underlie fluid management, including evidence-based recommendations (where tenable) and a rational approach for when and what to administer.

Key Controversies in Colloid and Crystalloid Fluid Utilization

Nearly 2 centuries have passed since the use of intravenous fluid became a foundational component of clinical practice. Despite a steady stream of published investigations on the topic, questions surrounding the choice, dose, timing, targets, and cost-effectiveness of various fluid options remain insufficiently answered. In recent years, 2 of the most debated topics reference the role of albumin in acute care and the safety of normal saline. Although albumin has a place in therapy for specific patient populations, its high cost relative to other fluids makes it a less desirable option for hospitals and health systems with escalating formulary scrutiny. Pharmacists bear responsibility for reconciling this disparity and supporting the rational use of albumin in acute care through a careful evaluation of recently published literature. In parallel, it has become clear that crystalloids should no longer be considered a homogenous class of fluids. The past reliance on normal saline has been questioned due to recent findings of renal dysfunction attributable to the solution's supraphysiologic chloride concentration. These safety concerns with 0.9% sodium chloride may result in a practice shift toward more routine use of "balanced crystalloids," such as lactated Ringer's or Plasma-Lyte, that mimic the composition of extracellular fluid. The purpose of this review is to summarize the evidence regarding these 2 important fluid controversies that are likely to affect hospital pharmacists in the coming decades - the evidence-based use of human albumin and the rising role of balanced salt solutions in clinical practice.

Intravenous solutions in the care of patients with volume depletion and electrolyte abnormalities

Infusion fluids are often given to restore blood pressure (volume resuscitation), but may also be administered to replace ongoing losses, match insensible losses, correct electrolyte or acid-base disorders, or provide glucose. The development of new infusion fluids has provided clinicians with a wide range of products. Although the choice for a certain infusion fluid is often driven more by habit than by careful consideration, we believe it is useful to approach infusion fluids as drugs and consider their pharmacokinetic and pharmacodynamic characteristics. This approach not only explains why infusion fluids may cause electrolyte and acid-base disturbances, but also why they may compromise kidney function or coagulation. In this teaching case, we present a 19-year-old patient in whom severe hypernatremia developed as a result of normal saline solution infusion and explore the pharmacokinetic and pharmacodynamic effects of frequently used infusion fluids. We review clinical evidence to guide the selection of the optimal infusion fluid.