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Early Detection of Muscle Weakness and Functional Limitations in the Critically Ill: A Retrospective Evaluation of Bioimpedance Spectroscopy
Author(s) -
Baldwin Claire E.,
Fetterplace Kate,
Beach Lisa,
Kayambu Geetha,
Paratz Jennifer,
Earthman Carrie,
Parry Selina M.
Publication year - 2020
Publication title -
journal of parenteral and enteral nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.935
H-Index - 98
eISSN - 1941-2444
pISSN - 0148-6071
DOI - 10.1002/jpen.1719
Subject(s) - interquartile range , medicine , mechanical ventilation , retrospective cohort study , critically ill , intensive care , bioelectrical impedance analysis , cardiology , body mass index , intensive care medicine
Background The potential for bioimpedance spectroscopy (BIS) to identify muscle weakness and functional limitations in critical illness is unknown; this study aimed to determine association of BIS with strength/function and differences between 3 intensive care units (ICUs). Methods A retrospective post hoc analysis of BIS, strength, and functional data from adults who required ≥48 hours of mechanical ventilation was conducted. Measures of body composition included the proportion (%) of total body water (TBW), fat mass (FM), and fat‐free mass (FFM). The Medical Research Council sum score (MRC‐ss) and Physical Function in ICU Test–Scored (PFIT‐s) were used for strength and functional assessments. Nonparametric cross‐sectional analyses were done at enrollment (≤48 hours of admission: site‐A, site‐C) and awakening from sedation (site‐A, site‐B). Raw impedance variables including 50‐kHz phase angle (PA) and impedance ratio (IR) were available from site‐A and site‐B. Results Participants were 135 adults (site‐A n=59, site‐B n=33, site‐C n=44), with a median (interquartile range) age of 59 (50–69) years. At enrollment, TBW%, FM%, and FFM% were similar between site‐A and site‐C ( P >.05); pooled data were not associated with MRC‐ss at awakening or MRC‐ss/PFIT‐s at ICU discharge. At awakening, there was less TBW%, less FFM%, and greater FM% at site‐B vs site‐A ( P ≤.001) but no associations with MRC‐ss/PFIT‐s when using pooled data. Trends with pooled data of a lower PA and higher IR being associated with awakening MRC‐ss were confirmed within site‐B (PA ρ =0.70, P ≤.001; IR ρ =−0.79, P ≤.001). Conclusion Site‐by‐site data suggest that raw impedance variables might be useful for screening weakness and poor function.