A physicochemical model of crystalloid infusion on acid-base status

Treatment Challenges and Controversies in the Management of Critically Ill Diabetic Ketoacidosis (DKA) Patients in Intensive Care Units

This review discusses the challenges and controversies in the treatment of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). Key areas include the selection of intravenous (IV) fluids, insulin therapy, strategies for preventing and monitoring cerebral edema (CE) by managing hyperglycemia overcorrection, electrolyte replacement, timing of nutrition, use of IV sodium bicarbonate, and airway management in critically ill DKA patients. Isotonic normal saline remains the standard for initial fluid resuscitation, though balanced solutions have been shown to have faster DKA resolution. Current guidelines recommend using continuous IV insulin for DKA management after fluid status has been restored potassium levels have been achieved and subcutaneous (SQ) insulin is started only after the resolution of metabolic acidosis. In comparison, the British guidelines recommend using SQ insulin glargine along with continuous regular IV insulin, which has shown faster DKA resolution and shorter hospital stays compared to continuous IV insulin alone. Although rare, rapid overcorrection of hyperglycemia with fluids and insulin can lead to CE, seizures, and death. Clinicians should be aware of risk factors and preventive strategies for CE. DKA frequently involves multiple electrolyte abnormalities, such as hypokalemia, hypophosphatemia, and hypomagnesemia and regular monitoring is essential for DKA management. Early initiation of oral nutrition has been shown to reduce intensive care unit and overall hospital length of stay. For impending respiratory failure, Bilevel positive airway pressure is not recommended due to aspiration risks. Instead, intubation and mechanical ventilation, with monitoring and management of acid-base and fluid status, are recommended. The use of sodium bicarbonate is discouraged due to the potential for worsening ketosis, hypokalemia, and risk of CE. However, IV sodium bicarbonate can be considered if the serum pH falls below 6.9, or when serum pH is less than 7.2 and/or serum bicarbonate levels are below 10 mEq/L, pre-and post-intubation, to prevent metabolic acidosis and hemodynamic collapse that occurs from apnea during intubation. Managing DKA and HHS in critically ill patients includes using balanced IV fluid solutions to restore volume status, followed by continuous IV insulin, early use of SQ glargine insulin, electrolyte replacement, and monitoring, CE preventive strategies by avoiding hyperglycemia overcorrection, early nutritional support, and appropriate airway management.

Balanced crystalloids (RInger's lactate) versus normal Saline in adults with diabetic Ketoacidosis in the Emergency Department (BRISK-ED): a pilot randomised controlled trial

BACKGROUND

Current diabetic ketoacidosis (DKA) treatment guidelines recommend using normal saline (NS); however, NS may delay DKA resolution by causing more hyperchloremic metabolic acidosis compared with balanced crystalloids. This study's objective was to determine the feasibility of a future multicentred randomised controlled trial (RCT) comparing intravenous Ringer's lactate (RL) with NS in managing ED patients with DKA.

METHODS

We conducted a parallel-arm, triple-blind, pilot RCT of adults (≥18 years) with DKA at a Canadian academic tertiary care ED. The primary feasibility outcome was recruitment rate (target ≥41.3% of eligible participants over the 1-year study period); the primary efficacy outcome was time elapsed from ED presentation to DKA resolution. The superiority margin for a clinically significant difference was chosen to be a 40% time reduction to DKA resolution. We also assessed the need to break allocation concealment and loss to follow-up. Patients with clinical suspicion for DKA were screened for inclusion and enrolled patients were randomised 1:1 to receive RL or NS. Patients, clinicians and outcome assessors were blinded to allocation.

RESULTS

We enrolled 52 (25 RL, 27 NS) of 60 eligible patients (86.7%), exceeding our target recruitment rate. There were more patients in the NS group with type 1 diabetes, and more patients in the RL group had an admission co-diagnosis in addition to DKA. For the 44 participants with confirmed laboratory evidence of resolution, median (IQR) time to DKA resolution for RL versus NS was 15.7 (10.4-18.8) and 12.7 (7.9-19.2) hours, respectively. There were no cases where blinding was broken, and there was no loss to follow-up.

CONCLUSIONS

This pilot trial demonstrated our protocol's feasibility by exceeding our target recruitment rate. Our results may be used to inform future multicentre trials to compare the safety and efficacy of RL and NS in managing DKA in the ED.

TRIAL REGISTRATION NUMBER

NCT04926740.

Management of diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is an acute life-threatening emergency in patients with diabetes, it can result in serious morbidity and mortality. Management of DKA requires reversing metabolic derangements, correcting volume depletion, electrolyte imbalances and acidosis while concurrently treating the precipitating illness. There are still controversies regarding certain aspects of DKA management. Different society guidelines have inconsistencies in their recommendations, while some aspects of treatment are not precise enough or have not been thoroughly studied. These controversies may include issues such as optimal fluid resuscitation, rate and type of Insulin therapy, potassium and bicarbonate replacement. Many institutions follow common society guidelines, however, other institutions either develop their own protocols for internal use or do not routinely use any protocols, resulting in inconsistencies in treatment and increased risk of complications and suboptimal outcomes. The objectives of this article are to review knowledge gaps and controversies in the treatment of DKA and provide our perspective on these issues. Moreover, we believe that special patient factors and comorbidities should receive more careful attention and consideration. Factors like pregnancy, renal disease, congestive heart failure, acute coronary syndrome, older age, use of sodium-glucose cotransporter-2 (SGLT2) inhibitors and site of care all impact the treatment approach and require tailored management strategies. However, guidelines often lack sufficient recommendations regarding specific conditions and comorbidities, we aim to address unique circumstances and provide an approach to managing complex patients with specific conditions and co-morbidities. We also sought to examine changes and trends in the treatment of DKA, illuminate on aspects of latest research with a perspective towards future developments and modifications.

The association between hypoalbuminemia and microcirculation, endothelium, and glycocalyx disorders in children with sepsis

OBJECTIVE

The objective of this study was to evaluate the association between serum albumin levels and microcirculation changes, glycocalyx degradation, and the clinical outcomes of interest.

METHODS

Observational, prospective study in children with sepsis. The primary outcome was the association between hypoalbuminemia and microcirculation disorders, endothelial activation and glycocalyx degradation using a perfused boundary region (PBR) (abnormal >2.0 μm on sublingual video microscopy) or plasma biomarkers (syndecan-1, angiopoietin-2).

RESULTS

A total of 125 patients with sepsis were included. The median age was 2.0 years (IQR 0.5-12.5). Children with hypoalbuminemia had more abnormal microcirculation with a higher PBR (2.16 μm [IQR 2.03-2.47] vs. 1.92 [1.76-2.28]; p = .01) and more 4-6 μm capillaries recruited (60% vs. 40%; p = .04). The low albumin group that had the worst PBR had the most 4-6 μm capillaries recruited (rho 0.29; p < .01), 48% higher Ang-2 (p = .04), worse annexin A5 (p = 0.03) and no syndecan-1 abnormalities (p = .21). Children with hypoalbuminemia and a greater percentage of blood volume in their capillaries needed mechanical ventilation more often (56.3% vs. 43.7%; aOR 2.01 95% CI 1.38-3.10: p < .01).

CONCLUSIONS

In children with sepsis, an association was found between hypoalbuminemia and microcirculation changes, vascular permeability, and greater endothelial glycocalyx degradation.

Balanced crystalloids (RInger's lactate) versus normal Saline in adults with diabetic Ketoacidosis in the Emergency Department (BRISK-ED): a protocol for a pilot randomized controlled trial

BACKGROUND

Current guidelines for diabetic ketoacidosis (DKA) recommend treatment with normal saline (NS). However, NS, with its high chloride concentrations, may worsen acidosis and contribute to a hyperchloremic metabolic acidosis. Alternatives to NS are balanced crystalloids (e.g. Ringer's Lactate [RL]) which have chloride concentrations similar to human plasma; therefore, treatment with balanced crystalloids may lead to faster DKA resolution. A recent systematic review and meta-analysis by Catahay et al. (2022) demonstrated the need for more blinded, high-quality trials comparing NS versus RL in the treatment of DKA.

METHODS

We describe a protocol for BRISK-ED (Balanced crystalloids [RInger's lactate] versus normal Saline in adults with diabetic Ketoacidosis in the Emergency Department). Our study is a single-centre, triple-blind, pilot randomized controlled trial (RCT) of adults (≥ 18 years) with DKA presenting to an academic tertiary care ED in London, Canada. Patients with clinical suspicion for DKA will be screened and those found to not meet DKA criteria or have euglycemic DKA will be excluded. We will aim to recruit 52 patients with DKA and will randomize them 1:1 to receive intravenous RL or NS. The primary feasibility outcome will be recruitment rate, and the primary efficacy outcome will be time elapsed from ED presentation to DKA resolution. Secondary outcomes include time to insulin infusion discontinuation, intensive care unit admission, in-hospital death, and major adverse kidney events within 30 days, defined as a composite of: i) death, ii) new renal replacement therapy, or iii) final serum creatinine ≥ 200% baseline at the earliest of hospital discharge or 30 days after ED presentation. Patients, clinicians, and outcome assessors will be blinded to allocation group. We will follow an intention-to-treat analysis. Gehan-Wilcoxon, Mann-Whitney U, or chi-square tests will be used to compare groups as appropriate.

DISCUSSION

The results of this pilot study will inform the design and feasibility of a full-scale, multicentre RCT to assess fluid choice in adult ED patients with DKA. If proven to demonstrate faster resolution of DKA, administration of balanced crystalloids may replace NS in diabetes treatment guidelines and improve patient and health systems outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov, Registration # NCT04926740; Registered June 15, 2021.

Endothelial and Glycocalyx Biomarkers in Children With Sepsis After One Bolus of Unbalanced or Balanced Crystalloids

OBJECTIVES

To assess the disruption of endothelial glycocalyx integrity in children with sepsis receiving fluid resuscitation with either balanced or unbalanced crystalloids. The primary outcome was endothelial glycocalyx disruption (using perfused boundary region >2 µm on sublingual video microscopy and syndecan-1 greater than 80 mg/dL) according to the type of crystalloid. The secondary outcomes were increased vascular permeability (using angiopoietin-2 level), apoptosis (using annexin A5 level), and associated clinical changes.

DESIGN

A single-center prospective cohort study from January to December 2021.

SETTING

Twelve medical-surgical PICU beds at a university hospital.

PATIENTS

Children with sepsis/septic shock before and after receiving fluid resuscitation with crystalloids for hemodynamic instability.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We included 106 patients (3.9 yr [interquartile range, 0.60-13.10 yr]); 58 of 106 (55%) received boluses of unbalanced crystalloid. This group had greater odds of endothelial glycocalyx degradation (84.5% vs 60.4%; adjusted odds ratio, 3.78; 95% CI, 1.49-9.58; p < 0.01) 6 hours after fluid administration, which correlated with increased angiopoietin-2 (rho = 0.4; p < 0.05) and elevated annexin A5 ( p = 0.04). This group also had greater odds of metabolic acidosis associated with elevated syndecan-1 (odds ratio [OR], 4.88; 95% CI, 1.23-28.08) and acute kidney injury (OR, 1.7; 95% CI, 1.12-3.18) associated with endothelial glycocalyx damage. The perfused boundary region returned to baseline 24 hours after receiving the crystalloid boluses.

CONCLUSIONS

Children with sepsis, particularly those who receive unbalanced crystalloid solutions during resuscitation, show loss and worsening of endothelial glycocalyx. The abnormality peaks at around 6 hours after fluid administration and is associated with greater odds of metabolic acidosis and acute kidney injury.

Normal Saline Versus Low Chloride Solutions in Treatment of Diabetic Ketoacidosis: A Systematic Review of Clinical Trials

Traditionally, normal saline solution (NSS) has been the fluid of choice in diabetic ketoacidosis (DKA) patients, but the NSS is an acidic fluid and may lead to the delayed resolution of DKA. A systemic review search was conducted on PubMed, Embase, and Central Cochrane Registry to compare the efficacy of low chloride solutions with normal saline solution in DKA resolution. Randomized clinical trials with normal saline as a control arm and low chloride solutions as an intervention arm were included. Four studies were included in the analysis. The investigated outcomes, including time to resolution for DKA and duration of insulin infusion, varied depending on the endpoint were reported in the studies. Overall, balanced solutions were generally associated with faster correction of pH. The time to reach overall DKA endpoints was comparable in both groups. We concluded that crystalloid solutions may be used as an initial resuscitation fluid in the DKA population and may lead to earlier resolution of acidosis. More clinical trial data is required to reach statistical significance for the hypothesis.

Impact of chloride-rich crystalloids on sepsis-associated community-acquired acute kidney injury recovery in critically ill patients

BACKGROUND

The use of chloride-rich crystalloids for resuscitation is associated with acute kidney injury (AKI). We aimed to explore the impact of resuscitation with chloride-rich crystalloids compared to balanced crystalloids on kidney function recovery in patients presenting with sepsis-associated community-acquired AKI (SACA-AKI).

METHODS

This is a single-center, historical cohort study of the adult intensive care unit (ICU) patients who presented to the emergency department (ED) with  sepsis-associated community-acquired-AKI at the Mayo Clinic, Rochester, MN, from January 2011 to April 2018. We divided the cohort into two groups based on the primary type of crystalloids they received in the ED and the first 48-h of ICU. The first group received primarily normal saline with < 25% balanced solutions, and the second group received at least ≥ 25% balanced crystalloids during the initial volume resuscitation.

RESULTS

Among the 732 enrolled patients [mean age: 64 ± 17, males: 461(63%)], 255 (35%) were in the second group and were found to have higher positive fluid balance during the first 48-h of admission compared to the first group [median + 2.3 (IQR: 0.4; 4.5) vs. + 1.1 (IQR: - 0.8; + 2.9) L, p < 0.001]. The second group had a higher rate of kidney function recovery by multivariate logistic regression after adjustments for known recovery risk factors (OR 1.46; 95% CI 1.05-2.04, p = 0.02).

CONCLUSIONS

The use of balanced crystalloids during the initial resuscitation is associated with higher odds of kidney function recovery in AKI patients with sepsis-associated community-acquired AKI.

Association Between Unbalanced Solutions and Acute Kidney Injury During Fluid Resuscitation in Children With Sepsis

OBJECTIVE

To evaluate the outcomes of patients with sepsis-associated organ dysfunction and septic shock who receive fluid resuscitation with balanced and unbalanced solutions in a middle-income country.

DESIGN

An observational, analytical cohort study with propensity score matching (PSM) in children admitted to a pediatric intensive care unit (PICU). Patients from one month to 17 years old who required fluid boluses due to hemodynamic instability were included. The primary outcome was the presence of acute kidney injury and the secondary outcomes were the need to begin continuous renal replacement therapy (CRRT), metabolic acidosis, PICU length of stay and mortality.

MEASUREMENTS AND MAIN RESULTS

Out of the 1,074 admissions to the PICU during the study period, 99 patients had sepsis-associated organ dysfunction and septic shock. Propensity score matching was performed including each patient´s baseline characteristics. The median age was 9.9 months (IQR 4.9-22.2) with 55.5% of the patients being male. Acute kidney injury was seen less frequently in children who received a balanced solution than in those who received an unbalanced solution (20.3% vs 25.7% P = 0.006 ORa, 0.75; 95% CI, 0.65-0.87), adjusted for disease severity. In addition, the group that received balanced solutions had less need for CRRT (3.3 % vs 6.5%; P = 0.02 ORa 0.48; 95% CI, 0.36-0.64) and a shorter PICU stay (6 days IQR 4.4-20.2 vs 10.2 days IQR 4.7-26; P < 0.001) than the group with unbalanced solutions. We found no difference in the frequency of metabolic acidosis (P = 0.37), hyperchloremia (P = 0.11) and mortality (P = 0.25) between the 2 groups.

CONCLUSION

In children with sepsis-associated organ dysfunction and septic shock, the use of unbalanced solutions for fluid resuscitation is associated with a higher frequency of acute kidney injury, a greater need for continuous renal support and a longer PICU stay compared to the use of balanced solutions, in a middle-income country.

Intraoperative Cell Saving: Is the Solution the Actual Problem?

Allogenic blood is a scarce, precious, and expensive resource that is not always available on demand. After termination of cardiopulmonary bypass, a large amount of residual pump blood remains in the extracorporeal circuit. The cell saver washes and concentrates this blood with .9% normal saline (NS), making autologous blood available and reducing the demand for allogenic blood. To quantify the quality of residual pump blood it was washed with either NS or a bicarbonate-buffered solution (Balsol). A qualitative in vitro analysis was conducted. Residual cardiopulmonary bypass blood from forty bypass circuits was processed with a cell saver device, using NS or Balsol solution. Measurements made compared the pH, electrolytes, metabolites, hematocrit, hemoglobin, osmolality, albumin, total protein, and strong ion difference. There were significant differences between the NS and Balsol groups. In the Balsol group, osmolality, electrolytes, and strong ion difference were similar to the constitution of Balsol solution after washing, but not with the normal saline group. Washing residual cardiopulmonary bypass pump blood with Balsol solution results in a resuspended red cell concentrate with a superior electrolyte profile and a strong ion difference similar to that of residual pump blood.

Intravenous and Oral Fluid Therapy in Neonatal Calves With Diarrhea or Sepsis and in Adult Cattle

Optimal fluid therapy protocols in neonatal calves and adult cattle are based on consideration of signalment, history, and physical examination findings, and individually tailored whenever laboratory analysis is available. Measurement of the magnitude of eye recession, duration of skin tenting in the lateral neck region, and urine specific gravity by refractometry provide the best estimates of hydration status in calves and cattle. Intravenous and oral electrolyte solutions (OES) are frequently administered to critically ill calves and adult cattle. Application of physicochemical principles indicates that 0.9% NaCl, Ringer's solution, and 5% dextrose are equally acidifying, lactated Ringer's and acetated Ringer's solution are neutral to mildly acidifying, and 1.3-1.4% sodium bicarbonate solutions are strongly alkalinizing in cattle. Four different crystalloid solutions are recommended for intravenous fluid therapy in dehydrated or septic calves and dehydrated adult cattle: (1) lactated Ringer's solution and acetated Ringer's solution for dehydrated calves, although neither solution is optimized for administration to neonatal calves or adult cattle; (2) isotonic (1.3%) or hypertonic (5.0 or 8.4%) solutions of sodium bicarbonate for the treatment of calves with diarrhea and severe strong ion (metabolic) acidosis and hyponatremia, and adult cattle with acute ruminal acidosis; (3) Ringer's solution for the treatment of metabolic alkalosis in dehydrated adult cattle, particularly lactating dairy cattle; and (4) hypertonic NaCl solutions (7.2%) and an oral electrolyte solution or water load for the rapid resuscitation of dehydrated neonatal calves and adult cattle. Much progress has been made since the 1970's in identifying important attributes of an OES for diarrheic calves. Important components of an OES for neonatal calves are osmolality, sodium concentration, the effective SID that reflects the concentration of alkalinizing agents, and the energy content. The last three factors are intimately tied to the OES osmolality and the abomasal emptying rate, and therefore the rate of sodium delivery to the small intestine and ultimately the rate of resuscitation. An important need in fluid and electrolyte therapy for adult ruminants is formulation of a practical, effective, and inexpensive OES.

Clinical Effects of Balanced Crystalloids vs Saline in Adults With Diabetic Ketoacidosis: A Subgroup Analysis of Cluster Randomized Clinical Trials

IMPORTANCE

Saline (0.9% sodium chloride), the fluid most commonly used to treat diabetic ketoacidosis (DKA), can cause hyperchloremic metabolic acidosis. Balanced crystalloids, an alternative class of fluids for volume expansion, do not cause acidosis and, therefore, may lead to faster resolution of DKA than saline.

OBJECTIVE

To compare the clinical effects of balanced crystalloids with the clinical effects of saline for the acute treatment of adults with DKA.

DESIGN, SETTING, AND PARTICIPANTS

This study was a subgroup analysis of adults with DKA in 2 previously reported companion trials-Saline Against Lactated Ringer's or Plasma-Lyte in the Emergency Department (SALT-ED) and the Isotonic Solutions and Major Adverse Renal Events Trial (SMART). These trials, conducted between January 2016 and March 2017 in an academic medical center in the US, were pragmatic, multiple-crossover, cluster, randomized clinical trials comparing balanced crystalloids vs saline in emergency department (ED) and intensive care unit (ICU) patients. This study included adults who presented to the ED with DKA, defined as a clinical diagnosis of DKA, plasma glucose greater than 250 mg/dL, plasma bicarbonate less than or equal to 18 mmol/L, and anion gap greater than 10 mmol/L. Data analysis was performed from January to April 2020.

INTERVENTIONS

Balanced crystalloids (clinician's choice of Ringer lactate solution or Plasma-Lyte A solution) vs saline for fluid administration in the ED and ICU according to the same cluster-randomized multiple-crossover schedule.

MAIN OUTCOMES AND MEASURES

The primary outcome was time between ED presentation and DKA resolution, as defined by American Diabetes Association criteria. The secondary outcome was time between initiation and discontinuation of continuous insulin infusion.

RESULTS

Among 172 adults included in this secondary analysis of cluster trials, 94 were assigned to balanced crystalloids and 78 to saline. The median (interquartile range [IQR]) age was 29 (24-45) years, and 90 (52.3%) were women. The median (IQR) volume of isotonic fluid administered in the ED and ICU was 4478 (3000-6372) mL. Cumulative incidence analysis revealed shorter time to DKA resolution in the balanced crystalloids group (median time to resolution: 13.0 hours; IQR: 9.5-18.8 hours) than the saline group (median: 16.9 hours; IQR: 11.9-34.5 hours) (adjusted hazard ratio [aHR] = 1.68; 95% CI, 1.18-2.38; P = .004). Cumulative incidence analysis also revealed shorter time to insulin infusion discontinuation in the balanced crystalloids group (median: 9.8 hours; IQR: 5.1-17.0 hours) than the saline group (median: 13.4 hours; IQR: 11.0-17.9 hours) (aHR = 1.45; 95% CI, 1.03-2.03; P = .03).

CONCLUSIONS AND RELEVANCE

In this secondary analysis of 2 cluster randomized clinical trials, compared with saline, treatment with balanced crystalloids resulted in more rapid resolution of DKA, suggesting that balanced crystalloids may be preferred over saline for acute management of adults with DKA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT02614040; NCT02444988.

The Impact of Intravenous Fluid Therapy on Acid-Base Status of Critically Ill Adults: A Stewart Approach-Based Perspective

One of the most important tasks of physicians working in intensive care units (ICUs) is to arrange intravenous fluid therapy. The primary indications of the need for intravenous fluid therapy in ICUs are in cases of resuscitation, maintenance, or replacement, but we also load intravenous fluid for purposes such as fluid creep (including drug dilution and keeping venous lines patent) as well as nutrition. However, in doing so, some facts are ignored or overlooked, resulting in an acid-base disturbance. Regardless of the type and content of the fluid entering the body through an intravenous route, it may impair the acid-base balance depending on the rate, volume, and duration of the administration. The mechanism involved in acid-base disturbances induced by intravenous fluid therapy is easier to understand with the help of the physical-chemical approach proposed by Canadian physiologist, Peter Stewart. It is possible to establish a quantitative link between fluid therapy and acid–base disturbance using the Stewart principles. However, it is not possible to accomplish this with the traditional approach; moreover, it may not be noticed sometimes due to the normalization of pH or standard base excess induced by compensatory mechanisms. The clinical significance of fluid-induced acid-base disturbances has not been completely clarified yet. Nevertheless, as fluid therapy may be the cause of unexplained acid-base disorders that may lead to confusion and elicit unnecessary investigation, more attention must be paid to understand this issue. Therefore, the aim of this paper is to address the effects of different types of fluid therapies on acid-base balance using the simplified perspective of Stewart principles. Overall, the paper intends to help recognize fluid-induced acid-base disturbance through bedside evaluation and choose an appropriate fluid by considering the acid-base status of a patient.

A Double-Blind, Randomized Control Trial of Rapidly Infused High Strong Ion Difference (SID) Fluid Versus Hartmann's Solution on Acid-Base Status in Sepsis Patients in the Emergency Department

BACKGROUND

Balanced fluids are preferred in initial resuscitation of septic patients based on several recent studies. The Stewart's concept on acid-base balance predicts that high strong ion difference (SID) fluid thus will increase the pH level. To date, the impact of high SID fluid in septic patient with metabolic acidosis remains uncertain. We conducted single center, randomized, double-blind trial to compare the effect of high SID fluid vs. Hartmann's solution on acid-base status in selected sepsis patients in the Emergency Department.

METHODS

Septic patient with hyperlactatemia and metabolic acidosis were randomized to receive either high SID fl uid or Hartmann's solution during initial fl uid resuscitation. The primary outcome measures the pH and bicarbonate levels difference pre- and post- resuscitation.

RESULTS

One hundred and sixty-two patients underwent randomization, 81 were assigned each to receive high SID fluid or Hartmann's solution. Both groups had similar baseline characteristics. High SID group received 23.5 mL/kg and the Hartmann's group received 22.7 mL/kg (p = 0.360). High SID fluid increased the mean (± SD) pH by 0.107 (± 0.09) vs. Hartmann's solution by 0.014 (± 0.12), p ≤ 0.001. Mean bicarbonate level increased signifi cantly in high SID group compared to Hartmann's (4.30 ± 3.76 vs. 1.25 ± 3.33, p ≤ 0.001). High SID group had higher post resuscitation lactate clearance than Hartmann's group (25.4 ± 28.3% vs. 12.0 ± 34.1%, p = 0.009). Shorter hospital stay was observed in highSID group 8.04 ± 5.96 days vs. Hartmann's group 12.18 ± 12.41 days (p = 0.048). Both groups showed no difference in incidence of pulmonary oedema, acute kidney injury and mortality.

CONCLUSIONS

Initial resuscitation using high SID fluid in selected septic patient improves pH and bicarbonate levels. The high SID group had better post resuscitation lactate clearance and shorter hospital stay.

Balanced Crystalloids Versus Saline in Critically Ill Adults: A Systematic Review and Meta-analysis

Background: The optimal resuscitative fluid remains controversial. Objective: To assess the association between crystalloid fluid and outcomes in critically ill adults. Methods: Cumulative Index to Nursing and Allied Health Literature, Scopus, PubMed, and Cochrane Central Register for Controlled Trials were searched from inception through July 2019. Cohort studies and randomized trials of critically ill adults provided predominantly nonperioperative fluid resuscitation with balanced crystalloids or 0.9% sodium chloride (saline) were included. Results: Thirteen studies (n = 30 950) were included. Balanced crystalloids demonstrated lower hospital or 28-/30-day mortality (risk ratio [RR] = 0.86; 95% CI = 0.75-0.99; I2 = 82%) overall, in observational studies (RR = 0.64; 95% CI = 0.41-0.99; I2 = 63%), and approached significance in randomized trials (RR = 0.94; 95% CI = 0.88-1.02; I2 = 0%). New acute kidney injury occurred less frequently with balanced crystalloids (RR = 0.91; 95% CI = 0.85-0.98; I2 = 0%), though progression to renal replacement therapy was similar (RR = 0.91; 95% CI = 0.79-1.04; I2 = 38%). In the sepsis cohort, odds of hospital or 28-/30-day mortality were similar, but the odds of major adverse kidney events occurring in the first 30 days were less with balanced crystalloids than saline (OR = 0.78; 95% CI = 0.66-0.91; I2 = 42%). Conclusion and Relevance: Resuscitation with balanced crystalloids demonstrated lower hospital or 28-/30-day mortality compared with saline in critically ill adults but not specifically those with sepsis. Balanced crystalloids should be provided preferentially to saline in most critically ill adult patients.

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.

The myth of 0.9% saline: neither normal nor physiological

Normal saline is the crystalloid of choice for fluid resuscitation with its utility born out of the cholera epidemic of 1832. However, its ubiquitous usage is being challenged because of a growing body of evidence suggesting that a large volume infusion of normal saline does in fact have deleterious effects on multiple body systems. Careful considerations should be given to the physiological effects of using large amounts of normal saline as one would with another pharmacological agents.

Acid-base assessment: when and how to apply the Henderson-Hasselbalch equation and strong ion difference theory

The Henderson-Hasselbalch equation is probably the most famous equation in biology but is more descriptive than mechanistic. The traditional approach to acid-base assessment using the Henderson-Hasselbalch equation provides a clinically useful and accurate method when plasma protein concentrations are within the reference range. The simplified strong ion approach is a mechanistic acid-base model that can provide new insight into complicated acid-base disturbances. The simplified strong ion approach should be used to evaluate acid-base balance whenever plasma protein concentrations are abnormal.

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.

Dose and type of crystalloid fluid therapy in adult hospitalized patients

OBJECTIVE

In this narrative review, an overview is given of the pros and cons of various crystalloid fluids used for infusion during initial resuscitation or maintenance phases in adult hospitalized patients. Special emphasis is given on dose, composition of fluids, presence of buffers (in balanced solutions) and electrolytes, according to recent literature. We also review the use of hypertonic solutions.

METHODS

We extracted relevant clinical literature in English specifically examining patient-oriented outcomes related to fluid volume and type.

RESULTS

A restrictive fluid therapy prevents complications seen with liberal, large-volume therapy, even though restrictive fluid loading with crystalloids may not demonstrate large hemodynamic effects in surgical or septic patients. Hypertonic solutions may serve the purpose of small volume resuscitation but carry the disadvantage of hypernatremia. Hypotonic solutions are contraindicated in (impending) cerebral edema, whereas hypertonic solutions are probably more helpful in ameliorating than in preventing this condition and improving outcome. Balanced solutions offer a better approach for plasma composition than unbalanced ones, and the evidence for benefits in patient morbidity and mortality is increasing, particularly by helping to prevent acute kidney injury.

CONCLUSIONS

Isotonic and hypertonic crystalloid fluids are the fluids of choice for resuscitation from hypovolemia and shock. The evidence that balanced solutions are superior to unbalanced ones is increasing. Hypertonic saline is effective in mannitol-refractory intracranial hypertension, whereas hypotonic solutions are contraindicated in this condition.

Whole body acid-base and fluid-electrolyte balance: a mathematical model

A cellular compartment was added to our previous mathematical model of steady-state acid-base and fluid-electrolyte chemistry to gain further understanding and aid diagnosis of complex disorders involving cellular involvement in critically ill patients. An important hypothesis to be validated was that the thermodynamic, standard free-energy of cellular H(+) and Na(+) pumps remained constant under all conditions. In addition, a hydrostatic-osmotic pressure balance was assumed to describe fluid exchange between plasma and interstitial fluid, including incorporation of compliance curves of vascular and interstitial spaces. The description of the cellular compartment was validated by close comparison of measured and model-predicted cellular pH and electrolyte changes in vitro and in vivo. The new description of plasma-interstitial fluid exchange was validated using measured changes in fluid volumes after isoosmotic and hyperosmotic fluid infusions of NaCl and NaHCO3. The validated model was used to explain the role of cells in the mechanism of saline or dilutional acidosis and acid-base effects of acidic or basic fluid infusions and the acid-base disorder due to potassium depletion. A module was created that would allow users, who do not possess the software, to determine, for free, the results of fluid infusions and urinary losses of water and solutes to the whole body.