Resuscitation with balanced electrolyte solution prevents hyperchloremic metabolic acidosis in patients with diabetic ketoacidosis

Buffered solutions versus 0.9% saline for resuscitation in critically ill adults and children

BACKGROUND

Fluid therapy is one of the main interventions provided for critically ill patients, although there is no general consensus regarding the type of solution. Among crystalloid solutions, 0.9% saline is the most commonly administered. Buffered solutions may offer some theoretical advantages (less metabolic acidosis, less electrolyte disturbance), but the clinical relevance of these remains unknown.

OBJECTIVES

To assess the effects of buffered solutions versus 0.9% saline for resuscitation in critically ill adults and children.

SEARCH METHODS

We searched the following databases to July 2018: CENTRAL, MEDLINE, Embase, CINAHL, and four trials registers. We checked references, conducted backward and forward citation searching of relevant articles, and contacted study authors to identify additional studies. We imposed no language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) with parallel or cross-over design examining buffered solutions versus intravenous 0.9% saline in a critical care setting (resuscitation or maintenance). We included studies on participants with critical illness (including trauma and burns) or undergoing emergency surgery during critical illness who required intravenous fluid therapy. We included studies of adults and children. We included studies with more than two arms if they fulfilled all of our inclusion criteria. We excluded studies performed in persons undergoing elective surgery and studies with multiple interventions in the same arm.

DATA COLLECTION AND ANALYSIS

We used Cochrane's standard methodological procedures. We assessed our intervention effects using random-effects models, but when one or two trials contributed to 75% of randomized participants, we used fixed-effect models. We reported outcomes with 95% confidence intervals (CIs).

MAIN RESULTS

We included 21 RCTs (20,213 participants) and identified three ongoing studies. Three RCTs contributed 19,054 participants (94.2%). Four RCTs (402 participants) were conducted among children with severe dehydration and dengue shock syndrome. Fourteen trials reported results on mortality, and nine reported on acute renal injury. Sixteen included trials were conducted in adults, four in the paediatric population, and one trial limited neither minimum or maximum age as an inclusion criterion. Eight studies involving 19,218 participants were rated as high methodological quality (trials with overall low risk of bias according to the domains: allocation concealment, blinding of participants/assessors, incomplete outcome data, and selective reporting), and in the remaining trials, some form of bias was introduced or could not be ruled out.We found no evidence of an effect of buffered solutions on in-hospital mortality (odds ratio (OR) 0.91, 95% CI 0.83 to 1.01; 19,664 participants; 14 studies; high-certainty evidence). Based on a mortality rate of 119 per 1000, buffered solutions could reduce mortality by 21 per 1000 or could increase mortality by 1 per 1000. Similarly, we found no evidence of an effect of buffered solutions on acute renal injury (OR 0.92, 95% CI 0.84 to 1.00; 18,701 participants; 9 studies; low-certainty evidence). Based on a rate of 121 per 1000, buffered solutions could reduce the rate of acute renal injury by 19 per 1000, or result in no difference in the rate of acute renal injury. Buffered solutions did not show an effect on organ system dysfunction (OR 0.80, 95% CI 0.40 to 1.61; 266 participants; 5 studies; very low-certainty evidence). Evidence on the effects of buffered solutions on electrolyte disturbances varied: potassium (mean difference (MD) 0.09, 95% CI -0.10 to 0.27; 158 participants; 4 studies; very low-certainty evidence); chloride (MD -3.02, 95% CI -5.24 to -0.80; 351 participants; 7 studies; very low-certainty evidence); pH (MD 0.04, 95% CI 0.02 to 0.06; 200 participants; 3 studies; very low-certainty evidence); and bicarbonate (MD 2.26, 95% CI 1.25 to 3.27; 344 participants; 6 studies; very low-certainty evidence).

AUTHORS' CONCLUSIONS

We found no effect of buffered solutions on preventing in-hospital mortality compared to 0.9% saline solutions in critically ill patients. The certainty of evidence for this finding was high, indicating that further research would detect little or no difference in mortality. The effects of buffered solutions and 0.9% saline solutions on preventing acute kidney injury were similar in this setting. The certainty of evidence for this finding was low, and further research could change this conclusion. Patients treated with buffered solutions showed lower chloride levels, higher levels of bicarbonate, and higher pH. The certainty of evidence for these findings was very low. Future research should further examine patient-centred outcomes such as quality of life. The three ongoing studies once published and assessed may alter the conclusions of the review.

Diabetic ketoacidosis and hyperosmolar hyperglycemic syndrome: review of acute decompensated diabetes in adult patients

Diabetic ketoacidosis and hyperosmolar hyperglycemic syndrome (HHS) are life threatening complications that occur in patients with diabetes. In addition to timely identification of the precipitating cause, the first step in acute management of these disorders includes aggressive administration of intravenous fluids with appropriate replacement of electrolytes (primarily potassium). In patients with diabetic ketoacidosis, this is always followed by administration of insulin, usually via an intravenous insulin infusion that is continued until resolution of ketonemia, but potentially via the subcutaneous route in mild cases. Careful monitoring by experienced physicians is needed during treatment for diabetic ketoacidosis and HHS. Common pitfalls in management include premature termination of intravenous insulin therapy and insufficient timing or dosing of subcutaneous insulin before discontinuation of intravenous insulin. This review covers recommendations for acute management of diabetic ketoacidosis and HHS, the complications associated with these disorders, and methods for preventing recurrence. It also discusses why many patients who present with these disorders are at high risk for hospital readmissions, early morbidity, and mortality well beyond the acute presentation.

Balanced Crystalloids Versus Saline for Perioperative Intravenous Fluid Administration in Children Undergoing Neurosurgery: A Randomized Clinical Trial

BACKGROUND

Balanced crystalloid solutions induce less hyperchloremia than normal saline, but their role as primary fluid replacement for children undergoing surgery is unestablished. We hypothesized that balanced crystalloids induce less chloride and metabolic derangements than 0.9% saline solutions in children undergoing brain tumor resection.

METHODS

In total, 53 patients (age range, 6 mo to 12 y) were randomized to receive balanced crystalloid (balanced group) or 0.9% saline solution (saline group) during and after (for 24 h) brain tumor resection. Serum electrolyte and arterial blood gas analyses were performed at the beginning of surgery (baseline), after surgery, and at postoperative day 1. The primary trial outcome was the absolute difference in serum chloride concentrations (post-preopΔCl) measured after surgery and at baseline. Secondary outcomes included the post-preopΔ of other electrolytes and base excess (BE); hyperchloremic acidosis incidence; and the brain relaxation score, a 4-point scale evaluated by the surgeon for assessing brain edema.

RESULTS

Saline infusion increased post-preopΔCl (6 [3.5; 8.5] mmol/L) compared with balanced crystalloid (0 [-1.0; 3.0] mmol/L; P<0.001). Saline use also resulted in increased post-preopΔBE (-4.4 [-5.0; -2.3] vs. -0.4 [-2.7; 1.3] mmol/L; P<0.001) and hyperchloremic acidosis incidence (6/25 [24%] vs. 0; P=0.022) compared with balanced crystalloid. Brain relaxation score was comparable between groups.

CONCLUSIONS

In children undergoing brain tumor resection, saline infusion increased variation in serum chloride compared with balanced crystalloid. These findings support the use of balanced crystalloid solutions in children undergoing brain tumor resection.

Fluid Therapy For Pediatric Patients With Diabetic Ketoacidosis: Current Perspectives

Diabetic ketoacidosis (DKA) is a preventable life-threatening complication of type 1 diabetes. Fluids form a crucial component of DKA therapy, goals being the restoration of intravascular, interstitial and intracellular compartments. Hydration reduces hyperglycemia by decreased counter-regulatory hormones, enhanced renal glucose clearance and augmented insulin sensitivity. However, for the last several decades, fluids in DKA have been subject of intense debate owing to their possible role in causation of cerebral edema (CE). Rehydration protocols have been modified to prevent major osmotic shifts, correct electrolyte imbalances and avoid cerebral or pulmonary edema. In DKA, a conservative deficit assumption ranging from 6.5% to 8.5% is preferred. Normal saline (0.9%) has been the traditional fluid of choice, for both, volume resuscitation and deficit replacement in DKA. However, the risk of AKI with its liberal chloride content remains a contentious issue. On the other hand, balanced crystalloids with restricted chloride content need more exploration in children with DKA, both with respect to DKA resolution and AKI. Although fluids are an integral part of DKA management, a fine balance is needed to avoid under-hydration or over-hydration during DKA management. In this narrative review, we discuss the current perspectives on fluids in pediatric DKA.

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.

"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.

Clinical Impact of Rapid Intravenous Rehydration With Dextrose Serum in Children With Acute Gastroenteritis

OBJECTIVES

We designed a study to compare rapid intravenous rehydration based on 0.9% normal saline (NS) or on NS + glucose 2.5% serum (SGS 2.5%) in patients with dehydration secondary to acute gastroenteritis. Our hypothesis is that the addition of glucose 2.5% serum (SGS 2.5%) to 0.9% saline solution could reduce the proportion of hospital admissions and return emergency visits in these patients. The secondary objective was to identify differences in the evolution of blood glucose and ketonemia between the groups.

METHODS

We designed a prospective randomized open-label clinical trial that was conducted in 2 tertiary hospitals over 9 months. Patients were randomized to receive SGS 2.5% or NS. Baseline clinical, analytical, and disease-related data were collected. Data were analyzed using SPSS.

RESULTS

The frequency of hospitalization in the SGS 2.5% group was 30.3% (n = 23) compared with 34.8% (n = 24) in the NS group, although the difference was not statistically significant (P = 0.59). The frequency of return visits to the emergency department was 17.8% (n = 8) in the NS group and 5.6% (n = 3) in the SGS 2.5% group (P = 0.091). Changes in glucose and ketone levels were more favorable in the SGS 2.5% group.

CONCLUSIONS

Our results enabled us to conclude that there were no significant differences in hospital admission or return visits to the emergency department between children with dehydration secondary to acute gastroenteritis.

Diabetic ketoacidosis in adult patients: an audit of factors influencing time to normalisation of metabolic parameters

BACKGROUND

Diabetic ketoacidosis (DKA) is an acute life-threatening metabolic complication of diabetes that imposes substantial burden on our healthcare system. There is a paucity of published data in Australia assessing factors influencing time to resolution of DKA and length of stay (LOS).

AIMS

To identify factors that predict a slower time to resolution of DKA in adults with diabetes.

METHODS

Retrospective audit of patients admitted to St Vincent's Hospital Melbourne between 2010 to 2014 coded with a diagnosis of 'Diabetic Ketoacidosis'. The primary outcome was time to resolution of DKA based on normalisation of biochemical markers. Episodes of DKA within the wider Victorian hospital network were also explored.

RESULTS

Seventy-one patients met biochemical criteria for DKA; median age 31 years (26-45 years), 59% were male and 23% had newly diagnosed diabetes. Insulin omission was the most common precipitant (42%). Median time to resolution of DKA was 11 h (6.5-16.5 h). Individual factors associated with slower resolution of DKA were lower admission pH (P < 0.001) and higher admission serum potassium level (P = 0.03). Median LOS was 3 days (2-5 days), compared to a Victorian state-wide LOS of 2 days. Higher comorbidity scores were associated with longer LOS (P < 0.001).

CONCLUSIONS

Lower admission pH levels and higher admission serum potassium levels are independent predictors of slower time to resolution of DKA. This may assist to stratify patients with DKA using markers of severity to determine who may benefit from closer monitoring and to predict LOS.

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.

Comparison of Plasma-Lyte A and Sodium Chloride 0.9% for Fluid Resuscitation of Patients With Diabetic Ketoacidosis

Purpose: The aim of this study was to compare Plasma-Lyte A (PL) and sodium chloride 0.9% (NS) in regard to time to resolution of diabetic ketoacidosis (DKA) when one fluid was used predominantly over the other for resuscitation. Methods: We performed a retrospective analysis of the records of patients treated for DKA at a large, academic medical center between July 1, 2013, and July 1, 2015. Patients were placed into the PL or NS group based on the predominant fluid they received during fluid resuscitation. Serum biochemistry variables were categorized as follows: initial, 2 to 4 hours, 4 to 6 hours, 6 to 12 hours, and 12 to 24 hours. The primary outcome was mean time to resolution of DKA. Results: Eighty-four patients were included in the study. The primary outcome of mean time to resolution of DKA was similar between the PL (19.74 hours) and NS (18.05 hours) groups (P = .5080). Patients treated with PL had a significantly greater rise in pH within the 4- to 6-hour and 6- to 12-hour periods. The chloride level was significantly higher and the anion gap was significantly lower for the NS group in the 6- to 12-hour period. Conclusion: These data suggest that the use of PL for fluid resuscitation in DKA may confer certain advantages over NS.

Spectrum of complications of severe DKA in children in pediatric Intensive Care Unit

Objectives:

To describe the spectrum of complications of Diabetic Ketoacidosis (DKA) observed in children admitted with severe DKA.

Methods:

Retrospective review of the medical records of all children admitted with the diagnosis of severe DKA in Pediatric Intensive Care Unit (PICU) of the Aga Khan University Hospital, from January 2010 to December 2015 was done. Data was collected on a structured proforma and descriptive statistics were applied.

Results:

Total 37 children were admitted with complicated DKA (1.9% of total PICU admission with 1.8% in 2010 and 3.4% in 2015). Mean age of study population was 8.1±4.6 years and 70% were females (26/37). Mean Prism III score was 9.4±6, mean GCS on presentation was 11±3.8 and mean lowest pH was 7.00±0.15. Complications observed included hyperchloremia (35.94%), hypokalemia (30.81%), hyponatremia (26.70%), cerebral edema (16.43%), shock (13.35%), acute kidney injury (10.27%), arrhythmias (3.8%), and thrombotic thrombocytopenic purpura (5.4%), while one patient had myocarditis and ARDS each. 13/37 children (35%) needed inotropic support, 11/37 (30%) required mechanical ventilation while only one patient required renal replacement therapy. Two patients (5.4%) died during their PICU stay.

Conclusion:

Hyperchloremia and other electrolyte abnormalities, cerebral edema and AKI are the most common complications of severe DKA.

Review of the Diagnostic Evaluation of Normal Anion Gap Metabolic Acidosis

Background

Normal anion gap metabolic acidosis is a common but often misdiagnosed clinical condition associated with diarrhea and renal tubular acidosis (RTA). Early identification of RTA remains challenging for inexperienced physicians, and diagnosis and treatment are often delayed.

Summary

The presence of RTA should be considered in any patient with a high chloride level when the CL^-/Na⁺ ratio is above 0.79, if the patient does not have diarrhea. In patients with significant hyperkalemia one should evaluate for RTA type 4, especially in diabetic patients, with a relatively conserved renal function. A still growing list of medications can produce RTA.

Key Messages

This review highlights practical aspects concerning normal anion gap metabolic acidosis.

The effect of balanced electrolyte solution versus normal saline in the prevention of hyperchloremic metabolic acidosis in diabetic ketoacidosis patients: a randomized controlled trial

Background: In resuscitation, normal saline could cause hyperchloremic metabolic acidosis, while balanced electrolyte solution is a crystalloid fluid resembling blood plasma with lower chloride content. This study compared the effect of normal saline and balanced electrolyte solution Ringerfundin (BES) as the resuscitation fluid in diabetic ketoacidosis (DKA) patients. Parameters applied in this study were standard base excess (SBE) as resuscitation’s result indicator and strong ion difference (SID) to measure chloride’s influence in developing hyperchloremic acidosis.Methods: A prospective, randomized, single blind controlled trial was conducted at the Emergency Department of Cipto Mangunkusumo Hospital. Thirty subjects with blood sugar >250 mg/dl, arterial pH <7.35 mg/dl, and positive blood ketone were randomly allocated to receive either normal saline (NS) or RingerfundinÒ (BES) as the standardized resuscitation protocol. Data analysis was performed using the unpaired T-test and the Mann Whitney test to compare the SBE and the SID means between both groups. Additional parameters were the level of consciousness, blood sugar level, vital signs, blood gas analysis, lactate, electrolyte, and blood ketone.Results: The mean SID in the BES group was significantly greater than the NS group of all measurements (p<0.05). The BES group had significantly higher mean SBE compared to the NS group at 18 hours (-4.88±5.69 vs -9.68±5.64; p=0.009), 24 hours (-3.99±4.27 vs -8.7±5.35; p=0.023), and 48 hours (-4.06±4.11 vs -7.01±5.46; p=0.009). BES resulted in non-significant higher delta SBE and SID than NS. Additional parameters were not different between both groups.Conclusion: This study showed that fluid resuscitation of DKA patients with BES resulted in slightly but not significantly higher mean actual SBE and SID than NS. suggesting that BES as an alternative fluid resuscitation to prevent hyperchloremic acidosis in diabetic ketoacidosis patients was not superior to NS.

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.

Review of Evidence for Adult Diabetic Ketoacidosis Management Protocols

BACKGROUND

Diabetic ketoacidosis (DKA) is an endocrine emergency with associated risk of morbidity and mortality. Despite this, DKA management lacks strong evidence due to the absence of large randomised controlled trials (RCTs).

OBJECTIVE

To review existing studies investigating inpatient DKA management in adults, focusing on intravenous (IV) fluids; insulin administration; potassium, bicarbonate, and phosphate replacement; and DKA management protocols and impact of DKA resolution rates on outcomes.

METHODS

Ovid Medline searches were conducted with limits "all adult" and published between "1973 to current" applied. National consensus statements were also reviewed. Eligibility was determined by two reviewers' assessment of title, abstract, and availability.

RESULTS

A total of 85 eligible articles published between 1973 and 2016 were reviewed. The salient findings were (i) Crystalloids are favoured over colloids though evidence is lacking. The preferred crystalloid and hydration rates remain contentious. (ii) IV infusion of regular human insulin is preferred over the subcutaneous route or rapid acting insulin analogues. Administering an initial IV insulin bolus before low-dose insulin infusions obviates the need for supplemental insulin. Consensus-statements recommend fixed weight-based over "sliding scale" insulin infusions although evidence is weak. (iii) Potassium replacement is imperative although no trials compare replacement rates. (iv) Bicarbonate replacement offers no benefit in DKA with pH > 6.9. In severe metabolic acidosis with pH < 6.9, there is lack of both data and consensus regarding bicarbonate administration. (v) There is no evidence that phosphate replacement offers outcome benefits. Guidelines consider replacement appropriate in patients with cardiac dysfunction, anaemia, respiratory depression, or phosphate levels <0.32 mmol/L. (vi) Upon resolution of DKA, subcutaneous insulin is recommended with IV insulin infusions ceased with an overlap of 1-2 h. (vii) DKA resolution rates are often used as end points in studies, despite a lack of evidence that rapid resolution improves outcome. (viii) Implementation of DKA protocols lacks strong evidence for adherence but may lead to improved clinical outcomes.

CONCLUSION

There are major deficiencies in evidence for optimal management of DKA. Current practice is guided by weak evidence and consensus opinion. All aspects of DKA management require RCTs to affirm or redirect management and formulate consensus evidence-based practice to improve patient outcomes.

Could Sentinel Skin Transplants Have Some Utility in Solid Organ Transplantation?

Accurate diagnosis of allograft rejection can be hazardous and challenging. A strategy that has emerged from experience with vascularized composite allografts (VCAs) is the use of sentinel skin transplants (SSTs)-portions of donor skin transplanted synchronously to an allograft. Work in nonhuman animal models and experience with VCAs suggest concordance between rejection occurring in the primary allograft and the SST, and that appearance of rejection in the SST may precede rejection in the primary allograft, permitting early therapeutic intervention that may improve outcomes with lower rates of chronic rejection. The encouraging findings reported in VCA transplantation raise the possibility that SST may also be useful in solid organ transplantation. Some evidence is provided by experience with abdominal wall transplantation in some intestinal and multivisceral transplant recipients. Results from those reports raise the possibility that rejection may manifest in the skin component before emergence in the intestinal allograft, providing a "lead time" during which treatment of rejection of the abdominal wall could prevent the emergence of intestinal rejection. It is plausible that these findings may be extrapolated to other solid organ allografts, especially those for which obtaining an accurate diagnosis of acute rejection can be hazardous and challenging, such as the lung or pancreas. However, more data are required to support widespread adoption of this technique.

Chloride Content of Fluids Used for Large-Volume Resuscitation Is Associated With Reduced Survival

OBJECTIVE

We sought to investigate if the chloride content of fluids used in resuscitation was associated with short- and long-term outcomes.

DESIGN

We identified patients who received large-volume fluid resuscitation, defined as greater than 60 mL/kg over a 24-hour period. Chloride load was determined for each patient based on the chloride ion concentration of the fluids they received during large-volume fluid resuscitation multiplied by the volume of fluids. We compared the development of hyperchloremic acidosis, acute kidney injury, and survival among those with higher and lower chloride loads.

SETTING

University Medical Center.

PATIENTS

Patients admitted to ICUs from 2000 to 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 4,710 patients receiving large-volume fluid resuscitation, hyperchloremic acidosis was documented in 523 (11%). Crude rates of hyperchloremic acidosis, acute kidney injury, and hospital mortality all increased significantly as chloride load increased (p < 0.001). However, chloride load was no longer associated with hyperchloremic acidosis or acute kidney injury after controlling for total fluids, age, and baseline severity. Conversely, each 100 mEq increase in chloride load was associated with a 5.5% increase in the hazard of death even after controlling for total fluid volume, age, and severity (p = 0.0015) over 1 year.

CONCLUSIONS

Chloride load is associated with significant adverse effects on survival out to 1 year even after controlling for total fluid load, age, and baseline severity of illness. However, the relationship between chloride load and development of hyperchloremic acidosis or acute kidney injury is less clear, and further research is needed to elucidate the mechanisms underlying the adverse effects of chloride load on survival.

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.

Hyperchloremia and moderate increase in serum chloride are associated with acute kidney injury in severe sepsis and septic shock patients

Background

Acute kidney injury and hyperchloremia are commonly present in critically ill septic patients. Our study goal was to evaluate the association of hyperchloremia and acute kidney injury in severe sepsis and septic shock patients.

Methods

In this retrospective cohort study in a provincial tertiary care hospital, adult patients with severe sepsis or septic shock and serum chloride measurements were included. Serum chloride was measured on a daily basis for 48 hours. Primary outcome was development of acute kidney injury (AKI) and association of AKI and serum chloride parameters was analyzed.

Results

A total of 240 patients were included in the study, 98 patients (40.8 %) had hyperchloremia. The incidence of acute kidney injury (AKI) was significantly higher in the hyperchloremia group (85.7 % vs 47.9 %; p < 0.001). Maximal chloride concentration in the first 48 hours ([Cl^-]_max) was significantly associated with AKI. In multivariate analysis, [Cl^-]_max was independently associated with AKI [adjusted odds ratio (OR) for AKI = 1.28 (1.02–1.62); p = 0.037]. The increase in serum chloride (Δ[Cl^-] = [Cl^-]_max – initial chloride concentration) demonstrated a dose-dependent relationship with severity of AKI. The mean Δ[Cl^-] in patients without AKI was 2.1 mmol/L while in the patients with AKI stage 1, 2 and 3 the mean Δ[Cl^-] was 5.1, 5.9 and 6.7 mmol/L, respectively. A moderate increase in serum chloride (Δ[Cl^-] ≥ 5 mmol/L) was associated with AKI [OR = 5.70 (3.00–10.82); p < 0.001], even in patients without hyperchloremia [OR = 8.25 (3.44–19.78); p < 0.001].

Conclusions

Hyperchloremia is common in severe sepsis and septic shock and independently associated with AKI. A moderate increase in serum chloride (Δ[Cl^-] ≥5 mmol/L) is associated with AKI even in patients without hyperchloremia.

Chloride toxicity in critically ill patients: What's the evidence?

Crystalloids have become the fluid of choice in critically ill patients and in the operating room both for fluid resuscitation and fluid maintenance. Among crystalloids, NaCl 0.9% has been the most widely used fluid. However, emerging evidence suggests that administration of 0.9% saline could be harmful mainly through high chloride content and that the use of fluid with low chloride content may be preferable in major surgery and intensive care patients. Administration of NaCl 0.9% is the leading cause of metabolic hyperchloraemic acidosis in critically ill patients and side effects might target coagulation, renal function, and ultimately increase mortality. More balanced solutions therefore may be used especially when large amount of fluids are administered in high-risk patients. In this review, we discuss physiological background favouring the use of balanced solutions as well as the most recent clinical data regarding the use of crystalloid solutions in critically ill patients and patients undergoing major surgery.

Modulation of the neurological and vascular complications by grape seed extract in a rat model of spinal cord ischemia–reperfusion injury by downregulation of both osteopontin and cyclooxygenase-2

In this study, we investigated the effects of grape seed extract (GSE) on the expression of osteopontin (OPN) and cyclooxygenase-2 (COX-2) in a rat model of spinal cord ischemia–reperfusion injury (SC-IRI). Fifty male rats were divided into 5 groups: control (CON); control + GSE (CON + GSE) (received GSE for 28 days); sham operated (Sham); IRI; and IRI + GSE. SC-IRI was induced by clamping the aorta just above the bifurcation for 45 min, and then the clamp was released for 48 h for reperfusion. IRI + GSE group received GSE for 28 days before SC-IRI. Sensory, motor, and placing/stepping reflex assessment was performed. Prostaglandin E2 (PGE2), thiobarbituric acid reactive substances (TBARs), and total antioxidant capacity (TAC) were measured in spinal cord homogenate. Immunohistochemical examination of the spinal cord for OPN and COX-2 were carried out. SC-IRI resulted in significant increase in plasma nitrite/nitrate level and spinal cord homogenate levels of TBARs and PGE2, and OPN and COX-2 expression with significant decrease in TAC. GSE improves the sensory and motor functions through decreasing OPN and COX-2 expression with reduction of oxidative stress parameters. We conclude a neuroprotective effect of GSE in SC-IRI through downregulating COX-2 and OPN expression plus its antioxidants effects.

Risk Factors and Outcomes in Patients With Hypernatremia and Sepsis

BACKGROUND

Hypernatremia is an uncommon but important electrolyte abnormality in intensive care unit patients. Sepsis is one of the most common causes of intensive care unit admission, but few studies about the role of hypernatremia in sepsis has been published yet. In this study, we aimed to explore the risk factors for developing hypernatremia in patients with sepsis, and the prognosis of patients with sepsis with or without hypernatremia was also assessed.

MATERIALS AND METHODS

In this retrospective cohort study of 51 septic intensive care unit patients at a single center, we examined the risk factors for the development of hypernatremia and the association of hypernatremia with clinical outcomes using univariate and multivariable analyses. Clinical outcomes such as mortality and hospital duration of patients with or without hypernatremia were also compared.

RESULTS

Acute Physiology and Chronic Health Evaluation II score (odds ratio = 1.15; 95% CI: 1.022-1.294) was found to be the only independent risk factor for hypernatremia in patients with sepsis. Moreover, patients developing hypernatremia during hospitalization showed significantly higher morbidity and mortality.

CONCLUSIONS

Acute Physiology and Chronic Health Evaluation II score may be an independent risk factor for hypernatremia in patients with sepsis. Moreover, hypernatremia is strongly associated with worse outcome in sepsis.

[NaCl 0.9 % for volume substitution : blessing or curse?]

The nonphysiological high chloride content of 0.9 % saline causes hyperchloremic acidosis and rapidly reduces renal perfusion in healthy volunteers-negative affects not seen with balanced crystalloids with low chloride content. Evidence from recently published studies strongly suggests that 0.9 % saline negatively effects outcome in surgical and critically ill patients. Major complications are the increased incidence of acute kidney injury and need for renal replacement therapy, as well as higher postoperative in-hospital mortality. Although implemented as the gold standard in many clinical guidelines, there are currently no data supporting the use of 0.9 % saline instead of modern balanced crystalloids. This is also and even particularly true for patients with hypokalemia and acute or chronic kidney injury. In-house training is an effective tool for sustainably raising the awareness of this issue among nursing and medical staff, and identifying alternative strategies to the use of NaCl 0.9 % in clinical practice.

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.

Which intravenous fluid for the surgical patient?

PURPOSE OF REVIEW

This review appraises recent evidence and provides clinical guidance on optimal perioperative fluid therapy.

RECENT FINDINGS

Choice of perioperative intravenous fluid continues to be the source of much debate. Not all crystalloids are equivalent, and there is growing evidence that balanced solutions are superior to 0.9% saline in many situations. Recent evidence from the critical care population has highlighted risks associated with synthetic colloids; this and the absence of demonstrable benefit in the surgical population make it difficult to recommend their use in the perioperative period. Giving the correct amount of fluid may be as important as the choice of the fluid used. There is increasing evidence that excessive positive fluid balance is harmful to patients but there have been no randomized trials comparing maintenance fluid strategy. A knowledge of the physiology and accurate estimation of fluid balance is important for water and electrolyte homeostasis until the patient is able to resume adequate enteral nutrition.

SUMMARY

Balanced crystalloids are the fluid of choice for perioperative resuscitation and optimization in patients not requiring blood products. Avoidance of a grossly positive sodium and water balance during the maintenance phase is likely to be important, but has not been assessed in randomized trials.

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.

Treatment of acute non-anion gap metabolic acidosis

Acute non-anion gap metabolic acidosis, also termed hyperchloremic acidosis, is frequently detected in seriously ill patients. The most common mechanisms leading to this acid-base disorder include loss of large quantities of base secondary to diarrhea and administration of large quantities of chloride-containing solutions in the treatment of hypovolemia and various shock states. The resultant acidic milieu can cause cellular dysfunction and contribute to poor clinical outcomes. The associated change in the chloride concentration in the distal tubule lumen might also play a role in reducing the glomerular filtration rate. Administration of base is often recommended for the treatment of acute non-anion gap acidosis. Importantly, the blood pH and/or serum bicarbonate concentration to guide the initiation of treatment has not been established for this type of metabolic acidosis; and most clinicians use guidelines derived from studies of high anion gap metabolic acidosis. Therapeutic complications resulting from base administration such as volume overload, exacerbation of hypertension and reduction in ionized calcium are likely to be as common as with high anion gap metabolic acidosis. On the other hand, exacerbation of intracellular acidosis due to the excessive generation of carbon dioxide might be less frequent than in high anion gap metabolic acidosis because of better tissue perfusion and the ability to eliminate carbon dioxide. Further basic and clinical research is needed to facilitate development of evidence-based guidelines for therapy of this important and increasingly common acid-base disorder.

Choices in fluid type and volume during resuscitation: impact on patient outcomes

We summarize the emerging new literature regarding the pathophysiological principles underlying the beneficial and deleterious effects of fluid administration during resuscitation, as well as current recommendations and recent clinical evidence regarding specific colloids and crystalloids. This systematic review allows us to conclude that there is no clear benefit associated with the use of colloids compared to crystalloids and no evidence to support the unique benefit of albumin as a resuscitation fluid. Hydroxyethyl starch use has been associated with increased acute kidney injury (AKI) and use of renal replacement therapy. Other synthetic colloids (dextran and gelatins) though not well studied do not appear superior to crystalloids. Normal saline (NS) use is associated with hyperchloremic metabolic acidosis and increased risk of AKI. This risk is decreased when balanced salt solutions are used. Balanced crystalloid solutions have shown no harmful effects, and there is evidence for benefit over NS. Finally, fluid resuscitation should be applied in a goal-directed manner and targeted to physiologic needs of individual patients. The evidence supports use of fluids in volume-responsive patients whose end-organ perfusion parameters have not been met.

Meta-analysis of high- versus low-chloride content in perioperative and critical care fluid resuscitation

Background

The objective of this systematic review and meta-analysis was to assess the relationship between the chloride content of intravenous resuscitation fluids and patient outcomes in the perioperative or intensive care setting.

Methods

Systematic searches were performed of PubMed/MEDLINE, Embase and Cochrane Library (CENTRAL) databases in accordance with PRISMA guidelines. Randomized clinical trials, controlled clinical trials and observational studies were included if they compared outcomes in acutely ill or surgical patients receiving either high-chloride (ion concentration greater than 111 mmol/l up to and including 154 mmol/l) or lower-chloride (concentration 111 mmol/l or less) crystalloids for resuscitation. Endpoints examined were mortality, measures of kidney function, serum chloride, hyperchloraemia/metabolic acidosis, blood transfusion volume, mechanical ventilation time, and length of hospital and intensive care unit stay. Risk ratios (RRs), mean differences (MDs) or standardized mean differences (SMDs) and confidence intervals were calculated using fixed-effect modelling.

Results

The search identified 21 studies involving 6253 patients. High-chloride fluids did not affect mortality but were associated with a significantly higher risk of acute kidney injury (RR 1·64, 95 per cent c.i. 1·27 to 2·13; P < 0·001) and hyperchloraemia/metabolic acidosis (RR 2·87, 1·95 to 4·21; P < 0·001). High-chloride fluids were also associated with greater serum chloride (MD 3·70 (95 per cent c.i. 3·36 to 4·04) mmol/l; P < 0·001), blood transfusion volume (SMD 0·35, 0·07 to 0·63; P = 0·014) and mechanical ventilation time (SMD 0·15, 0·08 to 0·23; P < 0·001). Sensitivity analyses excluding heavily weighted studies resulted in non-statistically significant effects for acute kidney injury and mechanical ventilation time.

Conclusion

A weak but significant association between higher chloride content fluids and unfavourable outcomes was found, but mortality was unaffected by chloride content.

Fluids in acute respiratory distress syndrome: pros and cons

PURPOSE OF REVIEW

Fluid resuscitation in acute respiratory distress syndrome (ARDS) is not well documented. Clinical evidence comes from studies in critically ill patients, but these patients respond differently to fluids depending on the presence or absence of sepsis.

RECENT FINDINGS

Clinical trials have shown adverse effects on kidney and hemostatic functions and trends toward increased mortality after hydroxyethyl starch infusion. Although well conducted, the methodology deserves attention concerning the infused volume, hemodynamic goals and the presence of septic and nonseptic patients. Small single-center studies have shown beneficial results associated with colloidal molecules through innovative methodological apparatus. Ongoing clinical trials allied to retrospective and prospective trials may favor the introduction of albumin in the critically ill population.

SUMMARY

In order to evaluate the pros and cons of using fluids in ARDS patients, it is important to carefully analyze the latest trials. Recent studies have emphasized the importance of better understanding endothelial pathophysiology during fluid management in ARDS patients. Certainly, further studies analyzing fluid strategies in septic and nonseptic ARDS patients are needed.

Incidence and characteristics of acute kidney injury in severe diabetic ketoacidosis

Aims

Acute kidney injury is a classical complication of diabetic ketoacidosis. However, to the best of our knowledge, no study has reported the incidence and characteristics of acute kidney injury since the consensus definition was issued.

Methods

Retrospective study of all cases of severe diabetic ketoacidosis hospitalised consecutively in a medical surgical tertiary ICU during 10 years. Patients were dichotomised in with AKI and without AKI on admission according to the RIFLE classification. Clinical and biological parameters were compared in these populations. Risk factors of presenting AKI on admission were searched for.

Results

Ninety-four patients were included in the study. According to the RIFLE criteria, 47 patients (50%) presented acute kidney injury on admission; most of them were in the risk class (51%). At 12 and 24 hours, the percentage of AKI patients decreased to 26% and 27% respectively. During the first 24 hours, 3 patients needed renal replacement therapy. Acute renal failure on admission was associated with a more advanced age, SAPS 2 and more severe biological impairments. Treatments were not different between groups except for insulin infusion. Logistic regression found 3 risk factors of presenting AKI on admission: age (odds ratio 1.060 [1.020–1.100], p<0.01), blood glucose (odds ratio 1.101 [1.039–1.166], p<0.01) and serum protein (odds ratio 0.928 [0.865–0.997], p = 0.04).

Conclusions

Acute kidney injury is frequently associated with severe diabetic ketoacidosis on admission in ICU. Most of the time, this AKI is transient and characterised by a volume-responsiveness to fluid infusion used in DKA treatment. Age, blood glucose and serum protein are associated to the occurrence of AKI on ICU admission.

Association between intravenous chloride load during resuscitation and in-hospital mortality among patients with SIRS

PURPOSE

Recent data suggest that both elevated serum chloride levels and volume overload may be harmful during fluid resuscitation. The purpose of this study was to examine the relationship between the intravenous chloride load and in-hospital mortality among patients with systemic inflammatory response syndrome (SIRS), with and without adjustment for the crystalloid volume administered.

METHODS

We conducted a retrospective analysis of 109,836 patients ≥ 18 years old that met criteria for SIRS and received fluid resuscitation with crystalloids. We examined the association between changes in serum chloride concentration, the administered chloride load and fluid volume, and the 'volume-adjusted chloride load' and in-hospital mortality.

RESULTS

In general, increases in the serum chloride concentration were associated with increased mortality. Mortality was lowest (3.7%) among patients with minimal increases in serum chloride concentration (0-10 mmol/L) and when the total administered chloride load was low (3.5% among patients receiving 100-200 mmol; P < 0.05 versus patients receiving ≥ 500 mmol). After controlling for crystalloid fluid volume, mortality was lowest (2.6%) when the volume-adjusted chloride load was 105-115 mmol/L. With adjustment for severity of illness, the odds of mortality increased (1.094, 95% CI 1.062, 1.127) with increasing volume-adjusted chloride load (≥ 105 mmol/L).

CONCLUSIONS

Among patients with SIRS, a fluid resuscitation strategy employing lower chloride loads was associated with lower in-hospital mortality. This association was independent of the total fluid volume administered and remained significant after adjustment for severity of illness, supporting the hypothesis that crystalloids with lower chloride content may be preferable for managing patients with SIRS.

Inpatient management of diabetes in adults: safety and good practice

Patients with diabetes typically occupy 15–20% of all inpatient hospital beds at any one time. The hospital physician therefore requires a good understanding of the safe and effective management of such patients in both the emergency and ward setting.

The case for 0.9% NaCl: is the undefendable, defensible?

Although 0.9% NaCl solution is by far the most-used fluid for fluid therapy in resuscitation, it is difficult to find a paper advocating its use over other types of crystalloid solutions. Literature on the deleterious effects of 0.9% NaCl has accumulated over the last decade, but critical appraisal of alternative crystalloid solutions is lacking. As such, the literature seems to suggest that 0.9% NaCl should be avoided at all costs, whereas alternative crystalloid solutions can be used without scrutiny. The basis of this negative evaluation of 0.9% NaCl is almost exclusively its effect on acid-base homeostasis, whereas the potentially deleterious effects present in other types of crystalloids are neglected. We have the challenging task of defending the use of 0.9% NaCl and reviewing its positive attributes, while an accompanying paper will argue against the use of 0.9% NaCl. It is challenging because of the large amount of literature, including our own, showing adverse effects of 0.9% NaCl. We will discuss why 0.9% NaCl solution is the most frequently used resuscitation fluid. Although it has some deleterious effects, all fluids share common features of concern. As such the emphasis on fluid resuscitation should be on volume rather than on composition and should be accompanied by a physiological assessment of the impact of fluids. In this paper, we hope to discuss the context within which fluids, specifically 0.9% NaCl, can be given in a safe and effective manner.

Isotonic crystalloid solutions: a structured review of the literature

BACKGROUND

Several different crystalloid solutions are available for i.v. fluid administration but there is little information about their specific advantages and disadvantages.

METHODS

We performed a systematic search of MEDLINE, EMBASE, and CENTRAL up until May 17, 2012, selecting all prospective human studies that directly compared any near-isotonic crystalloids and reported any outcome.

RESULTS

From the 5060 articles retrieved in the search, only 28 met the selection criteria. There was considerable heterogeneity among the studies. Several articles reported an increased incidence of hyperchloraemic acidosis with the use of normal saline, and others an increase in blood lactate levels when large amounts of Ringer's lactate solutions were infused. From the limited data available, normal saline administration appears to be associated with increased blood loss and greater red blood cell transfusion volumes in high-risk populations compared to Ringer's lactate. Possible effects of the different solutions on renal function, inflammatory response, temperature, hepatic function, glucose metabolism, and splanchnic perfusion are also reported. The haemodynamic profiles of all the solutions were similar.

CONCLUSIONS

Different solutions have different effects on acid-base status, electrolyte levels, coagulation, renal, and hepatic function. Whether these differences have clinical consequences remains unclear.

Should chloride-rich crystalloids remain the mainstay of fluid resuscitation to prevent 'pre-renal' acute kidney injury?: con

The high chloride content of 0.9% saline leads to adverse pathophysiological effects in both animals and healthy human volunteers, changes not seen after balanced crystalloids. Small randomized trials confirm that the hyperchloremic acidosis induced by saline also occurs in patients, but no clinical outcome benefit was demonstrable when compared with balanced crystalloids, perhaps due to a type II error. A strong signal is emerging from recent large propensity-matched and cohort studies for the adverse effects that 0.9% saline has on the clinical outcome in surgical and critically ill patients when compared with balanced crystalloids. Major complications are the increased incidence of acute kidney injury and the need for renal replacement therapy, and that pathological hyperchloremia may increase postoperative mortality. However, there are no large-scale randomized trials comparing 0.9% saline with balanced crystalloids. Some balanced crystalloids are hypo-osmolar and may not be suitable for neurosurgical patients because of their propensity to cause brain edema. Saline may be the solution of choice used for the resuscitation of patients with alkalosis and hypochloremia. Nevertheless, there is evidence to suggest that balanced crystalloids cause less detriment to renal function than 0.9% saline, with perhaps better clinical outcome. Hence, we argue that chloride-rich crystalloids such as 0.9% saline should be replaced with balanced crystalloids as the mainstay of fluid resuscitation to prevent ‘pre-renal' acute kidney injury.

Diabetic ketoacidosis in pregnancy

Pregnancies complicated by diabetic ketoacidosis are associated with increased rates of perinatal morbidity and mortality. A high index of suspicion is required, because diabetic ketoacidosis onset in pregnancy can be insidious, usually at lower glucose levels, and often progresses more rapidly as compared with nonpregnancy. Morbidity and mortality can be reduced with early detection of precipitating factors (ie, infection, intractable vomiting, inadequate insulin management or inappropriate insulin cessation, β-sympathomimetic use, steroid administration for fetal lung maturation), prompt hospitalization, and targeted therapy with intensive monitoring. A multidisciplinary approach including a maternal-fetal medicine physician, medical endocrinology specialists familiar with the physiologic changes in pregnancy, an obstetric anesthesiologist, and skilled nursing is paramount. Management principles include aggressive volume replacement, initiation of intravenous insulin therapy, correction of acidosis, correction of electrolyte abnormalities and management of precipitating factors, as well as monitoring of maternal-fetal response to treatment. When diabetic ketoacidosis occurs after 24 weeks of gestation, fetal status should be continuously monitored given associated fetal hypoxemia and acidosis. The decision for delivery can be challenging and must be based on gestational age as well as maternal-fetal responses to therapy. The natural inclination is to proceed with emergent delivery for nonreassuring fetal status that is frequently present during the acute episode, but it is imperative to correct the maternal metabolic abnormalities first, because both maternal and fetal conditions will likewise improve. Prevention strategies should include education of diabetic pregnant women about the risks of diabetic ketoacidosis, precipitating factors, and the importance of reporting signs and symptoms in a timely fashion.

The ideal crystalloid - what is 'balanced'?

PURPOSE OF REVIEW

This review explores the contemporary definition of the term 'balanced crystalloid' and outlines optimal design features and their underlying rationale.

RECENT FINDINGS

Crystalloid interstitial expansion is unavoidable, but also occurs with colloids when there is endothelial glycocalyx dysfunction. Reduced chloride exposure may lessen kidney dysfunction and injury with a possible mortality benefit. Exact balance from an acid-base perspective is achieved with a crystalloid strong ion difference of 24 mEq/l. This can be done simply by replacing 24 mEq/l of chloride in 0.9% sodium chloride with bicarbonate or organic anion bicarbonate substitutes. Potassium, calcium and magnesium additives are probably unnecessary. Large volumes of mildly hypotonic crystalloids such as lactated Ringer's solution reduce extracellular tonicity in volunteers and increase intracranial pressure in nonbrain-injured experimental animals. A total cation concentration of 154 mmol/l with accompanying anions provides isotonicity. Of the commercial crystalloids, Ringer's acetate solution is close to balanced from both acid-base and tonicity perspectives, and there is little current evidence of acetate toxicity in the context of volume loading, in contrast to renal replacement.

SUMMARY

The case for balanced crystalloids is growing but unproven. A large randomized controlled trial of balanced crystalloids versus 0.9% sodium chloride is the next step.