Chloride alterations in hospitalized patients: Prevalence and outcome significance

Association of hypochloremia with mortality among patients requiring continuous renal replacement therapy

BACKGROUND

Serum chloride derangement is common in critically ill patients requiring continuous renal replacement therapy (CRRT). We aimed to assess the association between serum chloride levels before and during CRRT with mortality.

METHODS

This is a retrospective cohort study of critically ill patients receiving CRRT for acute kidney injury from December 2006 through November 2015 in a tertiary referral hospital in the United States. We used logistic regression to assess serum chloride before and mean serum chloride during CRRT as predictors for 90 days mortality after CRRT initiation. The normal reference range for serum chloride was 99-108 mmol/L.

RESULTS

Of 1282 eligible patients, 25%, 50%, and 25% had hypochloremia, normochloremia, and hyperchloremia, respectively. The adjusted odds ratio for 90 days mortality in patients with hypochloremia before CRRT was 1.82 (95% CI 1.29-2.55). During CRRT, 4%, 70%, 26% of patients had mean serum chloride in the hypochloremia, normochloremia, and hyperchloremia range, respectively. The adjusted odds ratio for 90 days mortality in patients with mean serum chloride during CRRT in the hypochloremia range was 2.96 (95% CI 1.43-6.12). Hyperchloremia before and during CRRT was not associated with mortality. The greater serum chloride range during CRRT was associated with increased mortality (OR 1.29; 95% CI 1.13-1.47 per 5 mmol/L increase).

CONCLUSION

Hypochloremia before and during CRRT is associated with higher mortality.

Increase in chloride from baseline is independently associated with mortality in intracerebral hemorrhage patients admitted to intensive care unit: A retrospective study

Background

Hyperchloremia is associated with increased mortality in critically ill patients. The objective of this study was to investigate the association between increased chloride levels and mortality outcomes in intracerebral hemorrhage (ICH) patients admitted to the intensive care unit (ICU).

Methods

We performed a retrospective study of all patients diagnosed with ICH and included in the Medical Information Mart for Intensive Care (MIMIC-Ⅲ) from 2001 to 2012. Inclusion criteria were the first diagnosis of ICH, ICU length of stay (LOS) over 72 h, and not receiving hypertonic saline treatment. Serum chloride perturbation within 72 h of admission was evaluated as a predictor of outcomes. The increase in chloride from baseline was dichotomized based on an increase in chloride in 72 h (≤5 mmol/L or >5 mmol/L). The primary outcome was 90-day mortality.

Results

A total of 376 patients (54.5% male, median age 70 years, interquartile range:58-79 years) were included. The overall 90-day mortality was 32.2% (n=121), in-hospital mortality was 25.8% (n=97), and Day 2 acute kidney injury (AKI) occurred in 29.0% (n=109) of patients. The prevalence of hyperchloremia on admission, during the first 72 h, and an increase in chloride (>5 mmol/L) were 8.8%, 39.4%, and 42.8%, respectively. After adjusting for confounders, the hazard ratio of increase in chloride (>5 mmol/L) was 1.66 (95% confidence interval:1.05-2.64, P=0.031). An increase in chloride (>5 mmol/L) was associated with a higher odds ratio for 90-day mortality in both the AKI and non-AKI groups.

Conclusions

An increase in chloride from baseline is common in adult patients with ICH admitted to ICU. The increase is significantly associated with elevated mortality. These results support the significance of diligently monitoring chloride levels in these patients.

Electrolyte imbalance in infectious disease patients at King Abdulaziz Hospital, Jeddah

Objectives

Infectious diseases are the common cause of morbidity and mortality among humans. Electrolyte imbalance occurs frequently in patients with infectious diseases. This study aims to identify electrolyte imbalances in hospitalised patients with infectious diseases.

Methods

Two hundred and eighty-three patients with age mean 36.48 ± 18.86 years, consisting of 127 (53.4%) males, 111 (46.6%) females, enrolled in a retrospective cohort study carried out at the King Abdulaziz University Hospital, Jeddah, KSA from September to December 2020. All hospitalised patients with infectious diseases were included. Demographic data, comorbidity, and diagnosis were collected from patients’ sheets. Serum levels of electrolytes (chloride, potassium, sodium), urea, and creatinine were collected at admission (period 1), during hospital stay (period 2), and at discharge (period 3). Levels were compared during different periods.

Results

Most infectious diseases were viral infections (63.4%), while comorbidity was diabetes mellitus (7.1%). Serum chloride elevated from period 1 to period 3 (P = 0.046). Sodium elevated between period 1 and both period 2 and period 3 (P < 0.001). Urea decreased between period 1 and both period 2 (P = 0.018) and period 3 (P < 0.001). Creatinine decreased between period 1 and both period 2 and period 3 (P < 0.001) and between period 2 and period 3 (P < 0.001). Patients with decreased chloride and sodium levels were mostly in the 1st period, while those with decreased potassium levels were mostly in the period 2.

Conclusion

Prevalence of electrolyte imbalance in hospitalised patients with an infectious disease at the King Abdulaziz University Hospital, Jeddah was high, especially at admission and during the hospital stay.

Subtyping Hyperchloremia among Hospitalized Patients by Machine Learning Consensus Clustering

Background and Objectives: Despite the association between hyperchloremia and adverse outcomes, mortality risks among patients with hyperchloremia have not consistently been observed among all studies with different patient populations with hyperchloremia. The objective of this study was to characterize hyperchloremic patients at hospital admission into clusters using an unsupervised machine learning approach and to evaluate the mortality risk among these distinct clusters. Materials and Methods: We performed consensus cluster analysis based on demographic information, principal diagnoses, comorbidities, and laboratory data among 11,394 hospitalized adult patients with admission serum chloride of >108 mEq/L. We calculated the standardized mean difference of each variable to identify each cluster's key features. We assessed the association of each hyperchloremia cluster with hospital and one-year mortality. Results: There were three distinct clusters of patients with admission hyperchloremia: 3237 (28%), 4059 (36%), and 4098 (36%) patients in clusters 1 through 3, respectively. Cluster 1 was characterized by higher serum chloride but lower serum sodium, bicarbonate, hemoglobin, and albumin. Cluster 2 was characterized by younger age, lower comorbidity score, lower serum chloride, and higher estimated glomerular filtration (eGFR), hemoglobin, and albumin. Cluster 3 was characterized by older age, higher comorbidity score, higher serum sodium, potassium, and lower eGFR. Compared with cluster 2, odds ratios for hospital mortality were 3.60 (95% CI 2.33-5.56) for cluster 1, and 4.83 (95% CI 3.21-7.28) for cluster 3, whereas hazard ratios for one-year mortality were 4.49 (95% CI 3.53-5.70) for cluster 1 and 6.96 (95% CI 5.56-8.72) for cluster 3. Conclusions: Our cluster analysis identified three clinically distinct phenotypes with differing mortality risks in hospitalized patients with admission hyperchloremia.

Abnormal serum chloride is associated with increased mortality among unselected cardiac intensive care unit patients

Purpose

We sought to describe the association between serum chloride levels and mortality among unselected cardiac intensive care unit (CICU) patients.

Materials and methods

We retrospectively reviewed adult patients admitted to our CICU from 2007 to 2015. The association of dyschloremia and hospital mortality was assessed in a multiple variable model including additional confounders, and the association of dyschloremia and post-discharge mortality were assessed using Cox proportional-hazards analysis.

Results

9,426 patients with a mean age of 67±15 years (37% females) were included. Admission hypochloremia was present in 1,384 (15%) patients, and hyperchloremia was present in 1,606 (17%) patients. There was a U-shaped relationship between admission chloride and unadjusted hospital mortality, with increased hospital mortality among patients with hypochloremia (unadjusted OR 3.0, 95% CI 2.5–3.6, p<0.001) or hyperchloremia (unadjusted OR 1.9, 95% CI 1.6–2.3, p<0.001). After multivariate adjustment, hypochloremia remained associated with higher hospital mortality (adjusted OR 2.1, 95% CI 1.6–2.9, p <0.001). Post-discharge mortality among hospital survivors was higher among patients with admission hypochloremia (adjusted HR 1.3, 95% CI 1.1–1.6; p<0.001).

Conclusion

Abnormal serum chloride on admission to the CICU is associated with increased short- and long-term mortality, with hypochloremia being a strong independent predictor.

Usefulness of chloride levels for fluid resuscitation in patients undergoing targeted temperature management after out-of-hospital cardiac arrest

OBJECTIVE

Chloride is an important electrolyte in the body. In this study, we aimed to evaluate the associations between chloride levels on emergency department (ED) admission and neurologic outcomes by stratifying patients undergoing targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA) into three groups (hyper/normo/hypochloremia); we also assessed the effect of changes in chloride levels from baseline over time on outcomes.

METHODS

This retrospective, observational cohort study of 346 patients was conducted between 2011 and 2019. The chloride levels were categorized as hypochloremia, normochloremia, and hyperchloremia by predetermined definitions. The primary endpoint was poor neurologic outcomes after hospital discharge. We evaluated the associations between chloride levels on ED admission and neurologic outcomes and assess the effect of changes in chloride levels over time on clinical outcomes.

RESULTS

On ED admission, compared with normochloremia, hypochloremia was significantly associated with unfavorable neurologic outcomes (OR, 2.668; 95% CI, 1.217-5.850, P = 0.014). Over time, unfavorable neurologic outcomes were significantly associated with increases in chloride levels in the hyperchloremia and normochloremia groups after ED admission. The rates of poor neurologic outcomes in the hyperchloremia and normochloremia groups were increased by 14.2% at Time-12, 20.1% at Time-24, and 9.3% at Time-48 with a 1-mEq/L increase in chloride levels.

CONCLUSION

In clinical practice, chloride levels can be routinely and serially measured cost-effectively. Thus, baseline chloride levels may be a promising tool for rapid risk stratification of patients after OHCA. For fluid resuscitation after cardiac arrest, a chloride-restricted solution may be an early therapeutic strategy.

Increased mortality risk associated with serum sodium variations and borderline hypo- and hypernatremia in hospitalized adults

Background

This study aimed to evaluate short-term and long-term mortalities in a cohort of unselected hospitalized patients with serum sodium concentration ([Na⁺]) variations within and outside of reference range.

Methods

All adult patients admitted to the Mayo Clinic, Rochester, MN, USA from January 2011 to December 2013 (n = 147358) were retrospectively screened. Unique patients admitted during the study period were examined. The main exposure was serum [Na⁺] variation. Outcome measures were hospital and 1-year all-cause mortalities.

Results

A total of 60944 patients, mean age 63 ± 17 years, were studied. On admission, 17% (n = 10066) and 1.4% (n = 852) had hypo- and hypernatremia, respectively. During the hospital stay, 11044 and 4128 developed hypo- and hypernatremia, respectively, accounting for 52.3 and 82.9% of the total hypo- and hypernatremic patients. Serum [Na⁺] variations of ≥6 mEq/L occurred in 40.6% (n = 24 740) of the 60 944 patients and were significantly associated with hospital and 1-year mortalities after adjusting potential confounders (including demographics, comorbidities, estimated glomerular filtration rate, admission serum [Na⁺], number of [Na⁺] measurements and length of hospital stay). Adjusted odds ratios for hospital and 1-year mortalities increased with increasing [Na⁺] variations in a dose-dependent manner, from 1.47 to 5.48 (all 95% confidence intervals >1.0). Moreover, in fully adjusted models, [Na⁺] variations (≥6 mEq/L) within the reference range (135–145 mEq/L) or borderline hypo- or hypernatremia (133–137 and 143–147 mEq/L, respectively) compared with 138–142 mEq/L were associated with increased hospital and 1-year mortalities.

Conclusion

In hospitalized adults, [Na⁺] fluctuation (≥6 mEq/L) irrespective of admission [Na⁺] and borderline hypo- or hypernatremia are independent predictors of progressively increasing short- and long-term mortality burdens.

A deep learning backcasting approach to the electrolyte, metabolite, and acid-base parameters that predict risk in ICU patients

BACKGROUND

A powerful risk model allows clinicians, at the bedside, to ensure the early identification of and decision-making for patients showing signs of developing physiological instability during treatment. The aim of this study was to enhance the identification of patients at risk for deterioration through an accurate model using electrolyte, metabolite, and acid-base parameters near the end of patients' intensive care unit (ICU) stays.

METHODS

This retrospective study included 5157 adult patients during the last 72 hours of their ICU stays. The patients from the MIMIC-III database who had serum lactate, pH, bicarbonate, potassium, calcium, glucose, chloride, and sodium values available, along with the times at which those data were recorded, were selected. Survivor data from the last 24 hours before discharge and four sets of nonsurvivor data from 48-72, 24-48, 8-24, and 0-8 hours before death were analyzed. Deep learning (DL), random forest (RF) and generalized linear model (GLM) analyses were applied for model construction and compared in terms of performance according to the area under the receiver operating characteristic curve (AUC). A DL backcasting approach was used to assess predictors of death vs. discharge up to 72 hours in advance.

RESULTS

The DL, RF and GLM models achieved the highest performance for nonsurvivors 0-8 hours before death versus survivors compared with nonsurvivors 8-24, 24-48 and 48-72 hours before death versus survivors. The DL assessment outperformed the RF and GLM assessments and achieved discrimination, with an AUC of 0.982, specificity of 0.947, and sensitivity of 0.935. The DL backcasting approach achieved discrimination with an AUC of 0.898 compared with the DL native model of nonsurvivors from 8-24 hours before death versus survivors with an AUC of 0.894. The DL backcasting approach achieved discrimination with an AUC of 0.871 compared with the DL native model of nonsurvivors from 48-72 hours before death versus survivors with an AUC of 0.846.

CONCLUSIONS

The DL backcasting approach could be used to simultaneously monitor changes in the electrolyte, metabolite, and acid-base parameters of patients who develop physiological instability during ICU treatment and predict the risk of death over a period of hours to days.

Pediatric Mortality and Acute Kidney Injury Are Associated with Chloride Abnormalities in Intensive Care Units in the United States: A Multicenter Observational Study

Our objective was to determine in children in the intensive care unit (ICU) the incidence of hyperchloremia (>110 mmol/L) and hypochloremia (<98 mmol/L), the association of diagnoses with chloride abnormalities, and the associations of mortality and acute kidney injury (AKI) with chloride abnormalities. We analyzed the initial, maximum, and minimum chloride measurements of 14,684 children in the ICU with ≥1 chloride measurement in the Health Facts database between 2009 and 2016. For hyperchloremia and hypochloremia compared with normochloremia, mortality rates increased three to fivefold and AKI rates increased 1.5 to threefold. The highest mortality rate (7.7%; n = 95/1,234) occurred with hyperchloremia in the minimum chloride measurement group and the highest AKI rate (7.7%; n = 72/930) occurred with hypochloremia in the initial chloride measurement group. The most common diagnostic categories associated with chloride abnormalities were injury and poisoning; respiratory; central nervous system; infectious and parasitic diseases; and endocrine, nutritional, metabolic, and immunity disorders. Controlled for race, gender, age, and diagnostic categories, mortality odds ratios, and AKI odds ratios were significantly higher for hyperchloremia and hypochloremia compared with normochloremia. In conclusion, hyperchloremia and hypochloremia are independently associated with mortality and AKI in children in the ICU.

Hypochloraemia is associated with 28-day mortality in patients with septic shock: a retrospective analysis of a multicentre prospective registry

OBJECTIVES

Hyperchloraemia is associated with poor clinical outcomes in sepsis patients; however, this association is not well studied for hypochloraemia. We investigated the prevalence of chloride imbalance and the association between hypochloraemia and 28-day mortality in ED patients with septic shock.

METHODS

A retrospective analysis of data from 11 multicentre EDs in the Republic of Korea prospectively collected from October 2015 to April 2018 was performed. Initial chloride levels were categorised as hypochloraemia, normochloraemia and hyperchloraemia, according to sodium chloride difference adjusted criteria. The primary outcome was 28-day mortality. A multivariate logistic regression model adjusting for age, sex, comorbidities, acid-base state, sepsis-related organ failure assessment (SOFA) score, lactate and albumin level was used to test the association between the three chloride categories and 28-day mortality.

RESULTS

Among 2037 enrolled patients, 394 (19.3%), 1582 (77.7%) and 61 (3.0%) patients had hypochloraemia, normochloraemia and hyperchloraemia, respectively. The unadjusted 28-day mortality rate in patients with hypochloraemia was 27.4% (95% CI, 23.1% to 32.1%), which was higher than in patients with normochloraemia (19.7%; 95% CI, 17.8% to 21.8%). Hypochloraemia was associated with an increase in the risk of 28-day mortality (adjusted OR (aOR), 1.36, 95% CI, 1.00 to 1.83) after adjusting for confounders. However, hyperchloraemia was not associated with 28-day mortality (aOR 1.35, 95% CI, 0.82 to 2.24).

CONCLUSION

Hypochloraemia was more frequently observed than hyperchloraemia in ED patients with septic shock and it was associated with 28-day mortality.

Hospital-Acquired Serum Chloride Derangements and Associated In-Hospital Mortality

Background: We aimed to describe the incidence of hospital-acquired dyschloremia and its association with in-hospital mortality in general hospitalized patients. Methods: All hospitalized patients from 2009 to 2013 who had normal admission serum chloride and at least two serum chloride measurements in the hospital were studied. The normal range of serum chloride was defined as 100–108 mmol/L. Hospital serum chloride levels were grouped based on the occurrence of hospital-acquired hypochloremia and hyperchloremia. The association of hospital-acquired hypochloremia and hyperchloremia with in-hospital mortality was analyzed using logistic regression. Results: Among the total of 39,298 hospitalized patients, 59% had persistently normal hospital serum chloride levels, 21% had hospital-acquired hypochloremia only, 15% had hospital-acquired hyperchloremia only, and 5% had both hypochloremia and hyperchloremia. Compared with patients with persistently normal hospital serum chloride levels, hospital-acquired hyperchloremia only (odds ratio or OR 2.84; p < 0.001) and both hospital-acquired hypochloremia and hyperchloremia (OR 1.72; p = 0.004) were associated with increased in-hospital mortality, whereas hospital-acquired hypochloremia only was not (OR 0.91; p = 0.54). Conclusions: Approximately 40% of hospitalized patients developed serum chloride derangements. Hospital-acquired hyperchloremia, but not hypochloremia, was associated with increased in-hospital mortality.

Serum Chloride Levels at Hospital Discharge and One-Year Mortality among Hospitalized Patients

This study aimed to assess the one-year mortality risk based on discharge serum chloride among the hospital survivors. We analyzed a cohort of adult hospital survivors at a tertiary referral hospital from 2011 through 2013. We categorized discharge serum chloride; ≤96, 97–99, 100–102, 103–105, 106–108, and ≥109 mmoL/L. We performed Cox proportional hazard analysis to assess the association of discharge serum chloride with one-year mortality after hospital discharge, using discharge serum chloride of 103–105 mmoL/L as the reference group. Of 56,907 eligible patients, 9%, 14%, 26%, 28%, 16%, and 7% of patients had discharge serum chloride of ≤96, 97–99, 100–102, 103–105, 106–108, and ≥109 mmoL/L, respectively. We observed a U-shaped association of discharge serum chloride with one-year mortality, with nadir mortality associated with discharge serum chloride of 103–105 mmoL/L. When adjusting for potential confounders, including discharge serum sodium, discharge serum bicarbonate, and admission serum chloride, one-year mortality was significantly higher in both discharge serum chloride ≤99 hazard ratio (HR): 1.45 and 1.94 for discharge serum chloride of 97–99 and ≤96 mmoL/L, respectively; p < 0.001) and ≥109 mmoL/L (HR: 1.41; p < 0.001), compared with discharge serum chloride of 103–105 mmoL/L. The mortality risk did not differ when discharge serum chloride ranged from 100 to 108 mmoL/L. Of note, there was a significant interaction between admission and discharge serum chloride on one-year mortality. Serum chloride at hospital discharge in the optimal range of 100–108 mmoL/L predicted the favorable survival outcome. Both hypochloremia and hyperchloremia at discharge were associated with increased risk of one-year mortality, independent of admission serum chloride, discharge serum sodium, and serum bicarbonate.

Possible association between dysnatremias and mortality during hospitalization in patients undergoing acute hemodialysis: analysis from a Peruvian retrospective cohort

Objective:

To evaluate the association between dysnatremias or dyschloremias and mortality during hospitalization in patients with acute kidney injury (AKI) or chronic kidney disease (CKD) undergoing acute hemodialysis.

Methods:

We carried out a retrospective cohort study on adult patients undergoing acute hemodialysis with AKI or CKD diagnosis at a public hospital in Lima, Peru. Dysnatremias were categorized as hyponatremia (Na < 135mmol/L) or hypernatremia (Na > 145mmol/L), and dyschloremias were defined as hypochloremia (Cl < 98 mmol/L) or hyperchloremia (Cl > 109mmol/L). The outcome of interest was mortality during hospitalization. We performed generalized lineal Poisson family models with bias-corrected and accelerated non-parametric bootstrap to estimate the risk ratios at crude (RR) and adjusted analysis (aRR) by gender, age, HCO3 (for all patients) and Liaño score (only for AKI) with CI95%.

Results:

We included 263 patients (mean age: 54.3 years, females: 43%): 191 with CKD and 72 with AKI. Mortality was higher in patients with AKI (59.7%) than in patients with CKD (14.1%). In overall, patients with hypernatremia had a higher mortality during hospitalization compared to those who had normal sodium values (aRR: 1.82, 95% CI: 1.17-2.83); patients with hyponatremia did not have different mortality (aRR: 0.19, 95% CI: 0.69-2.04). We also found that hyperchloremia (aRR: 1.35, 95% CI: 0.83-2.18) or hypochloremia (aRR: 0.66, 95% CI: 0.30-14.78) did not increase mortality in comparison to normal chloride values. No association between dysnatremias or dyschloremias and mortality during hospitalization was found in CKD and AKI subgroups.

Conclusions:

In our exploratory analysis, only hypernatremia was associated with mortality during hospitalization among patients with AKI or CKD undergoing acute hemodialysis.

Hyperchloremia and acute kidney injury: a retrospective observational cohort study on a general mixed medical-surgical not ICU-hospitalized population

The aim of this observational retrospective cohort study was to analyze the association between hyperchloremia and serum chloride variation with in-hospital acute kidney injury (AKI) and mortality in a general, no-ICU hospitalized population. We performed a retrospective study on inpatient population admitted to Fondazione Policlinico Universitario A. Gemelli IRCCS between January 2010 and December 2014 with inclusion of adult patients with at least two values available for chloride, sodium and creatinine. Hyperchloremia was defined as serum chloride concentration ≥ 108 mmol/L (moderate hyperchloremia: chloremia between 108-110 mmol/L, severe hyperchloremia: chloremia > 110 mmol/L). According to the time of onset of the electrolyte disturbance, hyperchloremia was then classified as hospital acquired (HA) and community acquired (CA). In patients with HA-hyperchloremia, chloride variation (ΔCl) was calculated. In-hospital AKI was defined according to creatinine kinetics criteria occurring 48 h after hospital admission. Logistic regression analysis was used to evaluate the association between the exposures of interest and in-hospital AKI and mortality. A total of 24,912 hospital admissions met the inclusion criteria. Regression analyses showed that only severe HA-hyperchloremia was associated with increased risk of in-hospital AKI [odds ratio (OR) 2.60, 95% confidence interval (CI) 1.58, 4.30, p value < 0.001] and death (OR 3.89, 95% CI 2.11, 7.18, p value < 0.001). With increasing ΔCl, the OR of in-hospital AKI increased progressively (p value for trend = 0.005). In conclusion, severe hyperchloremia is an independent predictor for in-hospital AKI and mortality; HA-hyperchloremia is more detrimental for patient outcome; higher ΔCl from hospital admission is associated with increased risk of AKI.

Acetazolamide as a potent chloride-regaining diuretic: short- and long-term effects, and its pharmacologic role under the 'chloride theory' for heart failure pathophysiology

According to the "chloride theory" for heart failure (HF) pathophysiology, manipulation of the serum chloride concentration is an important therapeutic target. This study determined the short- and long-term effects of acetazolamide (Diamox), a potential chloride-regaining diuretic, on peripheral blood, serum electrolytes, and renal function. Effects of low-dose Diamox (250-500 mg/day) were evaluated in 30 HF patients for whom Diamox was added as de-novo/add-on decongestion therapy for acutely worsening HF (n = 18) or as modification therapy for serum hypochloremia in stable HF ( < 100 mEq/L; n = 12). Peripheral hematologic tests were performed at baseline, and at short- ( ≤ 10 days) and long-term ( ~ 60 days) time-points. In all 30 study patients of both groups, the serum chloride concentration increased in the short-term and even further over the long-term. The serum potassium concentration constantly decreased throughout the study period. Both the blood urea nitrogen and serum creatinine concentrations increased in the short-term, but returned to baseline levels over the long-term. Responders to Diamox (n = 13; defined by HF resolution and body weight loss ≥ 1 kg) in the decongestion group exhibited reduced serum b-type natriuretic peptide levels and a markedly increased serum chloride concentration, but the hemoglobin/hematocrit and serum creatinine concentrations did not change after treatment. In conclusion, acetazolamide is a potent candidate "chloride-regaining diuretic" for treating HF patients under the "chloride theory". Its effect to enhance the serum chloride concentration occurred within 10 days and persisted for at least ~ 60 days. Plasma volume and renal function were preserved under adequate diuretic treatment with acetazolamide.

Acid-Base Disturbances in Patients with Asthma: A Literature Review and Comments on Their Pathophysiology

Asthma is a common illness throughout the world that affects the respiratory system function, i.e., a system whose operational adequacy determines the respiratory gases exchange. It is therefore expected that acute severe asthma will be associated with respiratory acid-base disorders. In addition, the resulting hypoxemia along with the circulatory compromise due to heart–lung interactions can reduce tissue oxygenation, with a particular impact on respiratory muscles that have increased energy needs due to the increased workload. Thus, anaerobic metabolism may ensue, leading to lactic acidosis. Additionally, chronic hypocapnia in asthma can cause a compensatory drop in plasma bicarbonate concentration, resulting in non-anion gap acidosis. Indeed, studies have shown that in acute severe asthma, metabolic acid-base disorders may occur, i.e., high anion gap or non-anion gap metabolic acidosis. This review briefly presents studies that have investigated acid-base disorders in asthma, with comments on their underlying pathophysiology.

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.

Hyperchloremia Is Associated With Poorer Outcome in Critically Ill Stroke Patients

Background and Purpose: This study aims to explore the cause and predictive value of hyperchloremia in critically ill stroke patients.

Materials and Methods: We conducted a retrospective study of a prospectively collected database of adult patients with first-ever acute ischemic stroke (AIS) or intracerebral hemorrhage (ICH) admitted to the neurointensive care unit (NICU) of a university-affiliated hospital, between January 2013 and December 2016. Patients were excluded if admitted beyond 72 h from onset, if they required neurocritical care for less than 72 h, and were treated with hypertonic saline within 72 h or had creatinine clearance less than 15 mL/min.

Results: Of 405 eligible patients, the prevalence of hyperchloremia ([Cl⁻] ≥ 110 mmol/L) was 8.6% at NICU admission ([Cl⁻]₀) and 17.0% within 72 h ([Cl⁻]_max). Thirty-eight (9.4%) patients had new-onset hyperchloremia and 110 (27.1%) had moderate increase in chloride (Δ[Cl⁻] ≥ 5 mmol/L; Δ[Cl⁻] = [Cl⁻]_max − [Cl⁻]₀) in the first 72 h after admission, which were found to be determined by the sequential organ failure assessment score in multivariate logistic regression analysis. Neither total fluid input nor cumulative fluid balance had significant association with such chloride disturbance. New-onset hyperchloremia and every 5 mmol/L increment in Δ[Cl⁻] were both associated with increased odds of 30-day mortality and 6-month poor outcome, although no independent significance was found in multivariate models.

Conclusion: Hyperchloremia tends to occur in patients more severely affected by AIS and ICH. Although no independent association was found, new-onset hyperchloremia and every 5 mmol/L increment in Δ[Cl⁻] were related to poorer outcome in critically ill AIS and ICH patients.

Subject terms: clinical studies, intracranial hemorrhage, ischemic stroke, mortality/survival, quality and outcomes.

Associations of Fluid Amount, Type, and Balance and Acute Kidney Injury in Patients Undergoing Major Surgery

Fluid administration has been reported to be associated with an increased risk of acute kidney injury (AKI). We assessed whether, after correction for fluid balance, amount and chloride content of fluids administered have an independent association with AKI. We performed an observational study in patients after major surgery assessing the independent association of AKI with volume, chloride content and fluid balance, after adjustment for Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM) score, age, elective versus emergency surgery, and duration of surgery. We studied 542 consecutive patients undergoing major surgery. Of these, 476 patients had renal function tested as part of routine clinical care and 53 patients (11.1%) developed postoperative AKI. After adjustments, a 100 ml greater mean daily fluid balance was artificially associated with a 5% decrease in the instantaneous hazard of AKI: adjusted Hazard Ratio (aHR) 0.951, 95% confidence intervals (CI) 0.935 to 0.967, P <0.001. However, after adjustment for the proportion of chloride-restrictive fluids, mean daily fluid amounts and balances, POSSUM morbidity, age, duration and emergency status of surgery, and the confounding effect of fluid balance, every 5% increase in the proportion of chloride-liberal fluid administered was associated with an 8% increase in the instantaneous hazard of AKI (aHR 1.079, 95% CI 1.032 to 1.128, P=0.001), and a 100 ml increase in mean daily fluid amount given was associated with a 6% increase in the instantaneous hazard of AKI (aHR 1.061, 95% CI 1.047 to 1.075, P <0.001). After adjusting for key risk factors and for the confounding effect of fluid balance, greater fluid administration and greater administration of chloride-rich fluid were associated with greater risk of AKI.

Multivariable analysis of the association between electrolyte disturbances and mortality in cats

OBJECTIVES

Electrolyte disorders have been individually associated with mortality in small populations of cats with specific conditions, but the associations and interactions between electrolyte disturbances and outcome have not been evaluated in a large, heterogeneous population. It was hypothesized that abnormalities of sodium, chloride, potassium and calcium concentrations would be independently and proportionately associated with death from natural causes and with all-cause mortality in cats.

METHODS

An electronic database containing 7064 electrolyte profiles was constructed to assess the association between disorders of sodium, potassium, corrected-chloride and ionized calcium concentrations with non-survival by multivariable modelling. A second database containing 2388 records was used to validate the models constructed from the first database.

RESULTS

All four electrolytes assessed had non-linear U-shaped associations with case fatality rates, wherein concentrations clustered around the reference interval had the lowest case fatality rates, while progressively abnormal concentrations were associated with proportionately increased risk of non-survival (area under the receiver operator characteristic curve [AUROC] 0.689) or death (AUROC 0.750).

CONCLUSIONS AND RELEVANCE

Multivariable modelling suggested that these electrolyte disturbances were associated with non-survival and with death from natural causes independent of each other. The present study suggests that measurement of electrolyte concentrations is an important component of the assessment of cats in emergency rooms or intensive care units. Future studies should focus on confirming these associations in a prospective manner accounting for disease severity.

Chloride in intensive care units: a key electrolyte

Over the past few years, chloride has joined the league of essential electrolytes for critically ill patients. Dyschloremia can occur secondary to various etiologic factors before and during patient admission in the intensive care unit. Some cases are disease-related; others, treatment-related. Chloride abnormalities were shown in animal models to have adverse effects on arterial blood pressure, renal blood flow, and inflammatory markers, which have led to several clinical investigations. Hyperchloremia was studied in several settings and correlated to different outcomes, including death and acute kidney injury. Baseline hypochloremia, to a much lesser extent, has been studied and associated with similar outcomes. The chloride content of resuscitation fluids was also a subject of clinical research. In this review, we describe the effect of dyschloremia on outcomes in critically ill patients. We review the major studies assessing the chloride content of resuscitation fluids in the critically ill patient.

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.

Electrolyte Disturbances Are Associated with Non-Survival in Dogs-A Multivariable Analysis

Electrolyte disorders have been individually associated with mortality in small populations of dogs and cats with specific conditions, but the associations and interactions between electrolyte disturbances and outcome have not been evaluated in a large, heterogeneous population. It was hypothesized that abnormalities of sodium, chloride, potassium, and calcium concentrations would be independently and proportionately associated with death from natural causes and with all-cause mortality in dogs. An electronic database containing 33,117 electrolyte profiles was constructed to retrospectively assess the association between disorders of sodium, potassium, corrected chloride, and ionized calcium concentrations with non-survival and with death excluding euthanasia by multivariable modeling. A second database containing 11,249 records was used to validate the models constructed from the first database. All four electrolytes assessed had non-linear U-shaped associations with case fatality rates, wherein concentrations clustered around the reference interval had the lowest case fatality rates, while progressively abnormal concentrations were associated with proportionately increased risk of non-survival (AUROC 0.624) or death (AUROC 0.678). Multivariable modeling suggested that these electrolyte disturbances were associated with non-survival and with death from natural causes independent of each other. This study suggests that measurement of electrolyte concentrations is an important component of the assessment of dogs in emergency rooms or intensive care units. Future studies should focus on confirming these associations in a prospective manner accounting for disease severity.