Hemodynamic disturbances and oliguria during continuous kidney replacement therapy in critically ill children

Monitoring MUAC reflects the adequacy of nutrition support in critically ill children with a longer intensive care unit stay: A single-center prospective cohort study

BACKGROUND

Children who are critically ill frequently experience inadequate nutrition, resulting in changes in body composition. We investigated the nutrition status and body composition changes among children with prolonged stays in the pediatric intensive care unit (PICU), utilizing midupper arm circumference (MUAC), and triceps skinfold thickness (TSF) measurements.

METHODS

A single-center prospective cohort study monitored nutrition support for children admitted to the PICU for over 6 days. MUAC and TSF were measured at admission and every other day through the 15th day of the PICU stay. Target energy was caculated using the Schofield formula without stress correction, and recommended protein intake was set at 1.5 g/(kg/d). Factors influencing changes in anthropometry were analyzed through pairwise correlation and regression analysis.

RESULTS

Sixty children with a median PICU stay of 9 days were included. MUAC decreased by 2.53% in the first week and by 7.42% over 2 weeks. During the first week, average energy and protein intakes were only 53.0% and 41.3% of recommended levels, respectively. Decreases in MUAC correlated with mean cumulative energy deficits (1 week: r = 0.310 [P = 0.016]; 2 weeks: r = 0.504 [P = 0.023]) and mean cumulative protein deficits (1 week: r = 0.304 [P = 0.018]).

CONCLUSIONS

Many children with longer PICU stays did not met energy and protein recommendations. Decreases in MUAC were associated with deficits in energy and protein intake. Monitoring MUAC is a valuable tool for assessing nutrition support adequacy in children with longer PICU stays.

Outcomes of continuous kidney replacement therapy in pediatric patients: the impact of timing and predictors of mortality

BACKGROUND

While critically ill children receiving continuous kidney replacement therapy (CKRT) are at increased risk of mortality, few studies have examined the predictors of mortality in this population. This study aimed to evaluate CKRT outcomes, focusing on predictors of mortality.

METHODS

This cohort study included children aged 0-14 years who received CKRT. It collected baseline, clinical, and laboratory data. Descriptive analyses were performed. Least absolute shrinkage and selection operator (LASSO) regression was used to select the best predictors of mortality. A multivariable logistic regression model was constructed and validated with 1000 bootstraps.

RESULTS

This study included 113 children who received CKRT, of whom 83 (73.5%) survived and 30 (26.6%) died. Children admitted to the intensive care unit with a higher Pediatric Risk of Mortality III score, sepsis, longer intubation, or hypoalbuminemia (< 30 g/dL) were more likely to die. Multifactorial acute kidney injury was more common in those who died than in those who survived (83.3% vs. 31.3%, p < 0.01). As the exclusive indication for CKRT, fluid overload was more common in those who died than in those who survived (26.7% vs. 6.0%, p = 0.01). LASSO and multivariable regression models identified hemodynamic instability, as evidenced by inotropic support use, and abnormal coagulation, as evidenced by not using heparin anticoagulation, as independent predictors of mortality. Initiating CKRT late (> 48 h) was associated with mortality in the univariate but not the multivariate analysis.

CONCLUSIONS

Hemodynamic instability was the best predictor of mortality in critically ill children receiving CKRT.

Focus on oliguria during renal replacement therapy

Oliguria is a clinical symptom characterized by decreased urine output, which can occur at any stage of acute kidney injury and also during renal replacement therapy. In some cases, oliguria may resolve with adjustment of blood purification dose or fluid management, while in others, it may suggest a need for further evaluation and intervention. It is important to determine the underlying cause of oliguria during renal replacement therapy and to develop an appropriate treatment plan. This review looks into the mechanisms of urine production to investigate the mechanism of oliguria during renal replacement therapy from two aspects: diminished glomerular filtration rate and tubular abnormalities. The above conditions all implying a renal oxygen supply-demand imbalance, which is the signal of worsening kidney injury. It also proposes a viable clinical pathway for the treatment and management of patients with acute kidney injury receiving renal replacement therapy.

Doppler ultrasound in the assessment of renal perfusion before and during continuous kidney replacement therapy in the pediatric intensive care unit

BACKGROUND

This study aimed to assess observer variability and describe renal resistive index (RRI) and pulsatility index (PI) before and after onset of continuous kidney replacement therapy (CKRT). A secondary objective was to correlate Doppler ultrasound findings with those from direct measurement of renal blood flow (RBF).

METHODS

This is a prospective observational study in hemodynamically stable Maryland piglets with and without acute kidney injury (AKI) and in hemodynamically unstable critically ill children requiring CKRT. Doppler-based RRI and PI were assessed for each subject. Measurements were made by two different operators (pediatric intensivists) before and after CKRT onset.

RESULTS

Observer variability assessment in the measurement of RRI and PI rendered a moderate correlation for both RRI (ICC 0.65, IQR 0.51-0.76) and PI (ICC 0.63, IQR 0.47-0.75). RRI and PI showed no correlation with RBF or urine output. Baseline RRI and PI were normal in control piglets [RRI 0.68 (SD 0.02), PI 1.25 (SD 0.09)] and those with AKI [RRI 0.68 (SD 0.03), PI 1.20 (SD 0.13)]. Baseline RRI and PI were elevated in critically ill children (RRI 0.85, PI 2.0). PI and RRI did not change with CKRT in any study group.

CONCLUSIONS

Observer variability between inexperienced pediatric intensivists was comparable with that between senior and junior operators. Doppler-based calculations did not correlate with invasive measurements of RBF. RRI and PI were normal in hemodynamically stable piglets with and without AKI. RRI and PI were high in hemodynamically unstable patients requiring CKRT. RRI and PI did not change after CKRT onset, despite changes in hemodynamic status. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hemodynamic instability during connection to continuous kidney replacement therapy in critically ill pediatric patients

BACKGROUND

Emerging data suggest evidence of organ hypoperfusion during continuous kidney replacement therapy (CKRT). To facilitate kidney and global recovery, we must understand the hemodynamic risks associated with CKRT. We aimed to investigate frequency of hemodynamic instability and association with patient outcomes in pediatric CKRT.

METHODS

In a single-center study of CKRT patients between September 2016 and October 2018, we collected hemodynamic data using archived high-resolution physiologic data before and after connection. Primary outcome was hypotension defined as ≥ 20% decrease in baseline mean arterial pressure (MAP) for ≥ 2 consecutive minutes in the 60 min following connection. Secondary outcomes were tachycardia (≥ 20% increase in heart rate (HR)) and hemodynamic interventions.

RESULTS

Seventy-one patients median age 54 months (IQR 7-144), weight 16.7 kg (IQR 8-41), on hemodiafiltration had 304 filter connections, 4 (IQR 1-7) filters per patient; the median duration of CKRT was 9 days (IQR 3-20). The most common CKRT indication was AKI with fluid overload (48/71, 69%). There were 78 (27%) hypotension and 42 (14%) tachycardia events; cumulative duration of hypotension was 14 min IQR (3-31.75). Teams provided intervention in 17/304 (6%) of connections. Pediatric Logistic Organ Dysfunction 2 was the only independent predictor of hypotension (aOR 2.12 (CI 1.02-4.41)).

CONCLUSIONS

One in four and one in six pediatric CKRT filter connections were complicated by hypotension and tachycardia, respectively. Higher illness severity at CKRT initiation was independently associated with hypotension. Impact of CKRT-associated hemodynamic instability on global patient outcomes requires further targeted study. A higher resolution version of the Graphical abstract is available as Supplementary information.