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.

Invasive Mechanical Ventilation for Acute Viral Bronchiolitis: Retrospective Multicenter Cohort Study

OBJECTIVES

Bronchiolitis is a leading cause of PICU admission and a major contributor to resource utilization during the winter season. Management in mechanically ventilated patients with bronchiolitis is not standardized. We aimed to assess whether variations exist in management between the centers and then to assess if differences in PICU outcomes are found.

DESIGN

Retrospective cohort study.

SETTING

Three tertiary PICUs (Centers A, B, and C) in London, United Kingdom.

PATIENTS

Patients under 1 year of age (n = 462) who received invasive mechanical ventilation for acute viral bronchiolitis from 2012-2016.

INTERVENTIONS

None.

DESIGN

Retrospective cohort study.

MEASUREMENTS AND MAIN RESULTS

Data collected include all sedative agents administered, 48 hour cumulative fluid balance and location of endotracheal tube (oral or nasal). Primary outcome was duration of invasive mechanical ventilation. A generalized linear model was used to test for differences in duration of invasive mechanical ventilation between centers after adjustment for confounders: corrected gestational age, oxygen saturation index, bacterial coinfection, prematurity, respiratory syncytial virus status, risk of mortality score and comorbidity. Baseline characteristics were similar, other than a higher risk of mortality score at center A and higher admission oxygen saturation index at center C. Center A was associated with utilization of the most benzodiazepine and opiate sedation, the fewest nasal endotracheal tubes, and the highest mean cumulative fluid balance at 48 hours.Center A had an adjusted mean duration of invasive mechanical ventilation that was 44% longer than center C (95% CI, 25-66%; p < 0.001).The majority of confounders had an association with the duration of invasive mechanical ventilation; all were biologically plausible. Corrected gestational age was negatively associated with the duration of invasive mechanical ventilation for preterm infants less than 32 weeks, but not for term or 32-37 week infants (interaction effect). This meant that at a corrected age of 0 months, a less than 32-week infant had a mean duration that was 55% greater than a term infant: this effect had disappeared by 8 months old.

CONCLUSIONS

Between-center variations exist in both practices and outcomes. The relationship between these two findings could be further tested through implementation science with "optimal care bundles."

Improved oxygenation following methylprednisolone therapy and survival in paediatric acute respiratory distress syndrome

Background

Methylprednisolone remains a commonly used ancillary therapy for paediatric acute respiratory distress syndrome (PARDS), despite a lack of level 1 evidence to justify its use. When planning prospective trials it is useful to define response to therapy and to identify if there is differential response in certain patients, i.e. existence of ‘responders’ and ‘non responders’ to therapy. This retrospective, observational study carried out in 2 tertiary referral paediatric intensive care units aims to characterize the change in Oxygen Saturation Index, following the administration of low dose methylprednisolone in a cohort of patients with PARDS, to identify what proportion of children treated demonstrated response, whether any particular characteristics predict response to therapy, and to determine if a positive response to corticosteroids is associated with reduced Paediatric Intensive Care Unit mortality.

Methods

All patients who received prolonged, low dose, IV methylprednisolone for the specific indication of PARDS over a 5-year period (2011–2016) who met the PALICC criteria for PARDS at the time of commencement of steroid were included (n = 78).OSI was calculated four times per day from admission until discharge from PICU (or death). Patients with ≥20% improvement in their mean daily OSI within 72 hours of commencement of methylprednisolone were classified as ‘responders’. Primary outcome measure was survival to PICU discharge.

Results

Mean OSI of the cohort increased until the day of steroid commencement then improved thereafter. 59% of patients demonstrated a response to steroids. Baseline characteristics were similar between responders and non-responders. Survival to PICU discharge was significantly higher in ‘responders’ (74% vs 41% OR 4.14(1.57–10.87) p = 0.004). On multivariable analysis using likely confounders, response to steroid was an independent predictor of survival to PICU discharge (p = 0.002). Non-responders died earlier after steroid administration than responders (p = 0.003).

Conclusions

An improvement in OSI was observed in 60% of patients following initiation of low dose methylprednisolone therapy in this cohort of patients with PARDS. Baseline characteristics fail to demonstrate a difference between responders and non-responders. A 20% improvement in OSI after commencement of methylprednisolone was independently predictive of survival, Prospective trials are needed to establish if there is a benefit from this therapy.