Hyperchloremia Is Not an Independent Risk Factor for Postoperative Acute Kidney Injury in Pediatric Cardiac Patients

Urinary chloride excretion in critical illness and acute kidney injury: a paediatric hypothesis-generating cohort study post cardiopulmonary bypass surgery

Renal chloride metabolism is currently poorly understood but may serve as both a diagnostic and a treatment approach for acute kidney injury. We investigated whether plasma chloride, ammonia and glutamine as well as urinary chloride, ammonium and glutamine concentrations may serve as markers for acute kidney injury in paediatric patients. We conducted a prospective observational trial in a tertiary care paediatric intensive care unit. Ninety-one patients after cardiopulmonary bypass surgery were enrolled. Plasma glutamine, creatinine, (serum) albumin, urinary electrolytes and glutamine were collected pre-cardiopulmonary bypass surgery, at paediatric intensive care unit admission, and at 6, 12, 24, 48 and 72 h after paediatric intensive care unit admission. The urinary strong ion difference was calculated. The median urinary chloride excretion decreased from 51 mmol/L pre-cardiopulmonary bypass to 25 mmol/L at paediatric intensive care unit admission, and increased from 24 h onwards. Patients with acute kidney injury had lower urinary chloride excretion than those without. The median urinary strong ion difference was 59 mmol/L pre-cardiopulmonary bypass, rose to 131 mmol/L at 24 h and fell to 20 mmol/L at 72 h. The plasma chloride rose from 105 mmol/L pre-cardiopulmonary bypass to a maximum of 109 mmol/L at 24 h. At 24 h the plasma chloride concentration was associated with the presence of acute kidney injury. There was no association between plasma or urinary amino acids and chloride excretion or kidney injury. In conclusion, renal chloride excretion decreased in all patients, although this decrease was more pronounced in patients with acute kidney injury. Our findings may reflect a response of the kidneys to critical illness, and acute kidney injury may make these changes more pronounced. Targeting chloride metabolism may offer treatment approaches to acute kidney injury.

Modified del Nido cardioplegia is associated with low incidence of low main strong ion difference and hyperchloremia in pediatric patients after cardiac surgery

PURPOSE

The aims of this study were (1) to determine the associations of cardioplegic solutions with postoperative main strong ion difference (mSID), which is the difference between sodium ion concentration and chloride ion concentration ([Cl-]) and (2) to determine the associations of cardioplegic solutions with markers of organ dysfunction.

METHODS

In this retrospective cohort study, patients aged <5 years who underwent cardiac surgery in a tertiary teaching hospital were included. Patients were classified on the basis of the type of cardioplegic solution: modified del Nido cardioplegia (mDNC) and conventional cardioplegia (CC). The effects of mDNC on postoperative mSID and markers of organ functions were examined using propensity-matched analysis.

RESULTS

A total of 500 cases were included. mDNC solution was used in 163 patients (32.6%). After propensity score matching, patients in the mDNC group (n = 152) had significantly higher minimum mSID [28 (26, 30) mEq/L vs. 27 (25, 29) mEq/L, p = 0.02] and lower maximum [Cl-] [112 (109, 114) mEq/L vs. 113 (111, 117) mEq/L, p < 0.001] than patients in the CC group (n = 304). The incidences of low mSID and hyperchloremia in the mDNC group were significantly lower than those in the CC group (63.8 vs. 75.7%, p = 0.01 and 63.2 vs. 79.3%, p < 0.001, respectively). There was no significant difference in the incidence of postoperative acute kidney injury and B-type natriuretic peptide level between the two groups.

CONCLUSION

The use of modified del Nido cardioplegia may reduce the incidence of abnormal mSID and hyperchloremia compared with the use of a chloride-rich cardioplegic solution.

Urinary Chloride Excretion Postcardiopulmonary Bypass in Pediatric Patients-A Pilot Study

The aim of this study was to describe renal chloride metabolism following cardiopulmonary bypass (CPB) surgery in pediatric patients. A prospective observational trial in a tertiary pediatric intensive care unit (PICU) with 20 recruited patients younger than 2 years following CPB surgery was conducted. Urinary electrolytes, plasma urea, electrolytes, creatinine, and arterial blood gases were collected preoperatively, on admission to PICU and at standardized intervals thereafter. The urinary and plasma strong ion differences (SID) were calculated from these results at each time point. Fluid input and output and electrolyte and drug administration were also recorded. Median chloride administration was 67.7 mmol/kg over the first 24 hours. Urinary chloride (mmol/L; median interquartile range [IQR]) was 30 (19, 52) prior to surgery, 15 (15, 65) on admission, and remained below baseline until 24 hours. Plasma chloride (mmol/L; median [IQR]) was 105 (98, 107) prior to surgery and 101 (101, 106) on admission to PICU. It then increased from baseline, but remained within normal limits, for the remainder of the study. The urinary SID increased from 49.8 (19.1, 87.2) preoperatively to a maximum of 122.7 (92.5, 151.8) at 6 hours, and remained elevated until 48 hours. Plasma and urinary chloride concentrations were not associated with the development of acute kidney injury. Urinary chloride excretion is impaired after CPB. The urinary SID increase associated with the decrease in chloride excretion suggests impaired production and/or excretion of ammonium by the nephron following CPB, with gradual recovery postoperatively.

Association of hyperchloremia and acute kidney injury in pediatric patients with moderate and severe traumatic brain injury

PURPOSE

Acute kidney injury (AKI) is an established complication of adult traumatic brain injury (TBI) and known risk factor for mortality. Evidence demonstrates an association between hyperchloremia and AKI in critically ill adults but studies in children are scarce. Given frequent use of hypertonic saline in the management of pediatric TBI, we believe the incidence of hyperchloremia will be high and hypothesize that it will be associated with development of AKI.

METHODS

Single-center retrospective cohort study was completed at an urban, level 1 pediatric trauma center. Children > 40 weeks corrected gestational age and < 21 years of age with moderate or severe TBI (presenting GCS < 13) admitted between January 2016 and December 2021 were included. Primary study outcome was presence of AKI (defined by pediatric Kidney Disease: Improving Global Outcomes criteria) within 7 days of hospitalization and compared between patients with and without hyperchloremia (serum chloride ≥ 110 mEq/L).

RESULTS

Fifty-two children were included. Mean age was 5.75 (S.D. 5.4) years; 60% were male (31/52); and mean presenting GCS was 6 (S.D. 2.9). Thirty-seven patients (71%) developed hyperchloremia with a mean peak chloride of 125 (S.D. 12.0) mEq/L and mean difference between peak and presenting chloride of 16 (S.D. 12.7) mEq/L. Twenty-three patients (44%) developed AKI; of those with hyperchloremia, 62% (23/37) developed AKI, while among those without hyperchloremia, 0% (0/15) developed AKI (difference 62%, 95% CI 42-82%, p < 0.001). Attributable risk of hyperchloremia leading to AKI was 62.2 (95% CI 46.5-77.8, p = 0.0015).

CONCLUSION

Hyperchloremia is common in the management of pediatric TBI and is associated with development of AKI. Risk appears to be associated with both the height of serum chloride and duration of hyperchloremia.

Hyperchloremia and Postoperative Acute Kidney Injury in Adult Cardiac Patients: A Propensity-Matched Cohort Study

OBJECTIVES

Hyperchloremia is a potential risk factor for acute kidney injury (AKI) in critically ill patients. However, the relationship between hyperchloremia and postoperative AKI in adult patients undergoing cardiovascular surgery with cardiopulmonary bypass (CPB) remains unclear. The authors aimed to determine whether postoperative hyperchloremia was associated with postoperative AKI in these populations.

OBJECTIVES

Retrospective, single-center study.

SETTING

Tertiary care hospital.

PARTICIPANTS

Adult patients who underwent cardiovascular surgery with CPB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients with and without postoperative hyperchloremia were matched (1:1). The primary outcome was the rate of postoperative AKI diagnosed using the Kidney Disease: Improving Global Outcomes consensus criteria. Postoperative hyperchloremia was defined as postoperative serum chloride levels of >110 mmol/L during the first 48 hours. An increase in serum chloride levels (Δ[Cl^-]) was defined as the difference between the preoperative and maximum postoperative serum chloride levels during the first 48 hours ([Cl^-]_max). Propensity-score matching and univariate and multivariate logistic regression analyses were employed. A total of 323 patients were included. Propensity-score matching selected 55 pairs for the final comparison. The incidence of postoperative AKI did not differ between the two groups (47% v 46%, p = 1.0). In the multivariate logistic regression analysis, Δ[Cl^-] was associated independently with the development of postoperative AKI (odds ratio, 1.13; 95% confidence interval, 1.06-1.21; p < 0.001).

CONCLUSIONS

Exposure to postoperative hyperchloremia was not associated with postoperative AKI in adult patients undergoing cardiovascular surgery with CPB. However, an increase in the serum chloride level might be associated with postoperative AKI.

Hyperchloremia on Admission to Pediatric Intensive Care in Mechanically Ventilated Children is Associated with Impaired Renal Function

Objective  There is recent interest in the association between hyperchloremic metabolic acidosis and adverse outcomes. In vitro, hyperchloremia causes renal vasoconstriction and fall in glomerular filtration rate (GFR). The objective of this retrospective, observational study is to examine associations between chloride level at admission to pediatric intensive care (PICU) and worst GFR and requirement for renal replacement therapy. Materials and Methods  All admissions to PICU between 2009 and 2019 who received invasive mechanical ventilation and had blood gas analysis performed were included. Data analyzed included patient characteristics (age, gender, diagnosis, pediatric index of mortality [PIM]-2 score); results of initial blood gas; and maximum serum creatinine (then used to calculate minimum GFR). Primary outcome measure was worst GFR during PICU stay. Secondary outcome measures were requirement for renal replacement therapy and PICU mortality. Multivariable regression analysis was used to assess if admission chloride level was independently predictive of minimum GFR during PICU stay and to examine associations between hyperchloremia (>110 mEq/L) at admission and requirement for renal replacement therapy after adjustment for confounders. Results  Data were available for 2,217 patients. Median age was 16.4 months and 39% of patients were hyperchloremic at admission to PICU. Admission chloride level was independently predictive of worst GFR during PICU stay after adjustment for known confounders. Patients with hyperchloremia were not more likely to require renal replacement therapy or die than patients with normochloremia. Conclusion  Prospective studies are necessary to determine if high chloride, specifically chloride containing resuscitation fluids, have a causal relationship with poor outcomes.

Association of Chloride Ion and Sodium-Chloride Difference With Acute Kidney Injury and Mortality in Critically Ill Patients

Objectives

Derangements of chloride ion concentration ([Cl^-]) have been shown to be associated with acute kidney injury and other adverse outcomes. For a physicochemical approach, however, chloride ion concentration should be considered with sodium ion concentration. This study aimed to examine the association of chloride ion concentration and the main strong ion difference (difference between sodium ion concentration and chloride ion concentration) during the first 24 hours after admission into ICU with the development of acute kidney injury and mortality.

Design

Retrospective analyses using the eICU Collaborative Research Database.

Setting

ICUs in 208 hospitals across the United States between 2014 and 2015.

Patients

Critically ill patients who were admitted into the ICU.

Interventions

None.

Measurements and Main Results

A total of 34,801 patients records were analyzed. A multivariable logistic regression analysis for the development of acute kidney injury within 7 days of ICU admission shows that, compared with main strong iron difference 32-34 mEq/as a reference, there were significantly high odds for the development of acute kidney injury in nearly all groups with main strong iron difference more than 34 mEq/L (main strong iron difference = 34-36 mEq/L, odds ratio = 1.17, p = 0.02; main strong iron difference = 38-40 mEq/L, odds ratio = 1.40, p < 0.001; main strong iron difference = 40-42 mEq/L, odds ratio = 1.46, p = 0.001; main strong iron difference > 42 mEq/L, odds ratio = 1.56, p < 0.001). With chloride ion concentration 104-106 mEq/L as a reference, the odds for acute kidney injury were significantly higher only in chloride ion concentration less than or equal to 94 mEq/L and chloride ion concentration 98-100 mEq/L groups. Analyses conducted using inverse probability weighting showed significantly greater odds for ICU mortality in all groups with main strong iron difference greater than 34mEq/L other than the 36-38mEq/L group, as well as in the less than 26-mEq/L group.

Conclusions

Main strong iron difference measured on ICU presentation to the ICU predicts acute kidney injury within 7 days, with low and, in particular, high values representing increased risk. The association between the chloride levels and acute kidney injury is statistically insignificant in models incorporating main strong iron difference, suggesting main strong iron difference is a better predictive marker than chloride on ICU admission.

A meta-analysis of the incidence rate of postoperative acute kidney injury in patients with congenital heart disease

Background

Acute kidney injury (AKI) is a common complication of cardiac surgery. However, the incidence rate of AKI in patients with congenital heart disease (CHD) greatly varies between reports owing to the different definitions used for AKI. Therefore, this study was designed as a meta-analysis aimed at summarizing the incidence rate of AKI in patients with congenital heart disease (CHD) on the basis of different AKI criteria.

Methods

Studies published till April 24, 2020, on the incidence rate of AKI in patients with CHD, were retrieved from electronic databases and printed literature. To pool data from the included studies, the effect size, a combined statistics, was chosen and presented with the incidence rate and 95% confidence interval (CI). Heterogeneity was evaluated using I² statistics and Cochran Q test. The incidence rates obtained from the subgroup analysis according to study location, type of surgery, type of cohort, age, and AKI criteria) were also evaluated to determine the correlation of AKI with these factors. Publication bias was estimated using the Egger test.

Results

Thirty studies, comprising 9925 patients with AKI who had CHD, were included. Overall, the pooled incidence rate of AKI in the patients with CHD was 38.4% (95% CI, 32.0–44.7%). However, the incidence rate was not significantly affected by gender, study location, type of surgery, type of cohort, and AKI criteria. Moreover, age was significantly associated with the incidence of AKI, and the incidence rate was higher in the patients aged < 1 month than in those aged 1 month to 18 years, < 18 years, and ≥ 18 years (P < 0.05).

Conclusions

In this study, the estimated incidence rate of AKI in patients with CHD was 38.4% and may be influenced by age. These findings highlight the importance of further investigation of the specific causes of and effective preventive measures for AKI.

Serum Procalcitonin Level Predicts Acute Kidney Injury After Traumatic Brain Injury

BACKGROUND

A common non-neurologic complication after traumatic brain injury (TBI), acute kidney injury (AKI) is a risk factor of mortality. Some studies confirmed the predictive value of procalcitonin (PCT) on AKI in several clinical settings. We designed this study to explore the predictive value of PCT on AKI after TBI.

METHODS

We retrospectively enrolled patients with TBI admitted to our hospital from February 2015 to June 2019. Multivariate logistic regression analysis was performed to find the risk factors of AKI and construct a predictive model for AKI. Receiver operating characteristics curves were drawn to compare the predictive value of PCT and the constructed model.

RESULTS

A total of 214 patients were included in this study. The incidence of AKI after TBI was 25.70% in this study. Compared with the non-AKI group, the AKI group had higher age (P = 0.031), lower Glasgow Coma Scale (P < 0.001), and higher incidence of coagulopathy (P < 0.001) and shock (P < 0.001). Moreover, patients complicated with AKI had higher in-hospital mortality (P < 0.001) and worse 90-day outcome (P < 0.001). Multivariate logistic regression analysis indicated that age (P = 0.033), PCT (P = 0.002), serum chlorine (P = 0.011), and creatinine (P < 0.001) were independent risk factors of AKI. We constructed a predictive model using these 4 risk factors. The area under receiver operating characteristics curves of the predictive model was 0.928, which was significantly higher than that of a single PCT value (area under receiver operating characteristics curves = 0.833) (Z = 2.395, P < 0.05).

CONCLUSIONS

PCT is valuable in predicting AKI after TBI. To avoid AKI after TBI, physicians can adjust treatment strategies according to the level of PCT.

The Year in Review: Anesthesia for Congenital Heart Disease 2019

This review focuses on the literature published from January 2019 to February 2020 that is of interest to anesthesiologists taking care of children and adults with congenital heart disease. Five themes are addressed during this time period, and 59 peer-reviewed articles are discussed.