Bioelectrical Impedance Phase Angle and Morbidity and Mortality in Critically Ill Children

Abstract

Background Nutrition markers may be useful for diagnosis and monitoring and, also, as additional indicators of estimating death risk. We tested the association of body composition indicators (mid–upper arm circumference and phase angle) with pediatric intensive care unit (PICU) length of stay and mortality in critically ill pediatric patients. Methods Data from children aged 2 months–18 years were collected, and bioelectrical impedance was performed to obtain phase angle. Severity was evaluated by scoring the Pediatric Index of Mortality. Descriptive statistics were reported for nominal variables. Receiver operating characteristic curve was used to analyze the association of phase angle with 30‐day mortality and to find the best cutoff. Survival probabilities and PICU length of stay were estimated using the Kaplan‐Meier method. Results We evaluated 247 children with a median age of 4.8 years whose main cause of admission was sepsis. Survival curves showed higher survival in patients with phase angle >2.8° compared with patients with phase angle ≤2.8° (P < .0001). Kaplan‐Meier time‐to‐event analysis showed that children with lower phase angle values were more likely to remain in the PICU (hazard ratio, 1.84; P = .003). Lower survival was also observed in patients who presented mid–upper arm circumference values ≤5th percentile (P < .03). Conclusions Mid–upper arm circumference and phase angle were associated with mortality and morbidity in critically ill children, suggesting that these parameters may be useful not only for nutrition diagnosis and monitoring, but also as an additional indicator in estimating prognosis.

The clinical use of longitudinal bio-electrical impedance vector analysis in assessing stabilization of children with severe acute malnutrition

“…On average, both children with edematous SAM and wasting had lower PA than community children and low PA is reported to be associated with poor clinical outcome [28,29,48,49]. However, based on fit criteria, the models we tested did not suggest PA to contribute more than anthropometry alone towards explaining mortality, duration of hospital stay or time-to-mortality or time-todischarge.…”

“…PA reflects the phase shift between the current and voltage that results from the electrochemical membrane [25] and is associated with both cell membrane integrity, cell size, and cell mass and also with tissue resistance which depends on lean tissue and hydration status [26,27]. A low PA is associated with several diseases and higher mortality risk [13] and the use of clinical cut-off values have been suggested to identify children at risk of poor health outcome [28,29].…”

Comment on “Bioelectrical Impedance Phase Angle and Morbidity and Mortality in Critically Ill Children”

“…We read with interest the recent study of bioelectrical impedance analysis (BIA) in critically ill children, in which the authors report a challenge to conform with 1 of the standard BIA conditions (side of electrode placement).…”

“…Challenges with standard BIA conditions, as acknowledged by Zamberlan et al, are rarely reported. Some have used non‐standard BIA conditions, with patients asked to stand during BIA measurement.…”

Response to “Comment on ‘Bioelectrical Impedance Phase Angle and Morbidity and Mortality in Critically Ill Children’”

“…Thus, BIA does not seem to be a good method to evaluate body composition in cases where these 2 principles are not valid, such as critically ill patients who usually present with hydration disorders, since the amount of total body water interferes in FFM and fat mass estimation. Taking this into account, the aim of our study was not to use the body composition estimation by BIA but rather the PA whose measurement indirectly reflects the FFM, and it is not subjected to prediction equations and it is not influenced by hydration. Thus, to avoid the hydration bias in FFM, we did not use the body compartments estimation by BIA, and we just considered the PA values.…”