Introduction
Materials and methods
Study setting and patient sample
Anthropometry
Intra- and extracellular water volumes measurements
Body cell mass and fat-free mass calculations
Hemodialysis
Patient data
Statistical analysis
Results
Characteristics | Value |
---|---|
Demographics and health status | |
Age, years (±SD) | 62.4 ± 19.5 |
Male gender, number (%) | 19 (61.2) |
SAPS II at ICU admission (±SD) | 60.0 ± 19.5 |
Weight at ICU admission, kg (±SD) | 64.8 ± 10.5 |
Height, cm (±SD) | 167 ± 11.1 |
Body mass index at ICU admission, kg/m2 (±SD) | 23.9 ± 3.8 |
Malnourished at ICU admission, number (%) | 4 (12.9) |
ICU stay | |
Reason for ICU admission, number (%) | |
Septic shock | 16 (51.6) |
Cardiogenic shock | 7 (22.6) |
Neurological failure | 5 (16.1) |
Postoperative complications | 3 (9.7) |
Day of body composition assessment | |
Length of ICU stay before measurements, days (±SD) | 7.9 ± 4.7 |
Mechanical ventilation, number (%) | 18 (58.1) |
Vasopressors, number (%) | 0 |
Body temperature, °C (±SD) | 37.0 ± 0.4 |
Hemodialysis | |
Ultrafiltration, L (±SD) | -3.8 ± 0.8 |
Dialysate sodium concentration, mmol/L (±SD) | 143.0 ± 3.5 |
Dialysate temperature, °C (±SD) | 36.4 ± 0.5 |
Pre-dialysis plasma sodium concentration, mmol/L (±SD) | 137.8 ± 4.3 |
Post-dialysis plasma sodium concentration, mmol/L (±SD) | 140.8 ± 3.1 |
Intradialytic sodium gradient (±SD) | 5.1 ± 2.7 |
Intradialytic sodium balance, mmol (±SD) | -323 ± 242 |
Pre-dialysis plasma creatinine concentration, μmol/L (±SD) | 427.2 ± 211.8 |
Post-dialysis plasma creatinine concentration, μmol/L (±SD) | 240.4 ± 119.5 |
Pre-dialysis plasma osmolality, mmol/kg (±SD) | 301.5 ± 13.3 |
Post-dialysis plasma osmolality, mmol/kg (±SD) | 297.3 ± 7.3 |
Fluid dynamics induced by hemodialysis
Measurements | Pre-dialysis | Post-dialysis | P value |
---|---|---|---|
R1 (5 Khz), Ω (±SD) | 366.7 ± 73.7 | 407.1 ± 88.3 | <0.001 |
R2 (1 Mhz), Ω (±SD) | 425.9 ± 94.2 | 471.9 ± 116.3 | <0.001 |
Height2/R1, cm2/Ω (±SD) | 80.1 ± 23.6 | 72.4 ± 21.1 | <0.001 |
Height2/R2, cm2/Ω (±SD) | 69.7 ± 21.5 | 63.3 ± 20.5 | <0.001 |
Weight, kg (±SD) | 68.4 ± 11.2 | 65.1 ± 10.8 | <0.001 |
ECW, kg (±SD) | 22.8 ± 7.8 | 20.9 ± 7.1 | <0.001 |
ICW, kg (±SD) | 17.9 ± 4.4 | 16.6 ± 4.5 | <0.001 |
ECW/ICW (±SD) | 1.26 ± 0.2 | 1.26 ± 0.2 | 0.84 |
BCM, kg (±SD) | 24.3 ± 3.8 | 24.0 ± 3.8 | 0.61 |
FFMa, kg (±SD) | 49.1 ± 10.2 | 46.8 ± 9.4 | 0.03 |
BCM/weight, % | 36.2 ± 6.3 | 37.5 ± 6.9 | <0.001 |
BCM/FFM, % | 50.5 ± 6.8 | 52.1 ± 7.2 | <0.001 |
n
| Change in ECW, % (±SD) | Change in ICW, % (±SD) | |
---|---|---|---|
Reason for ICU admission | |||
Septic shock | 16 | -7.13 ± 4.26 | -6.95 ± 3.66 |
Cardiogenic shock | 7 | -12.21 ± 4.99a | -10.92 ± 7.52 |
Neurological failure | 5 | -5.64 ± 1.36 | -4.90 ± 2.7 |
Postoperative complications | 3 | -7.28 ± 3.71 | -7.28 ± 3.71 |
Sex | |||
Male | 19 | -7.76 ± 4.83 | -7.36 ± 5.38 |
Female | 12 | -8.03 ± 4.84 | -8.33 ± 4.39 |
Malnutrition at ICU admission | |||
Present | 4 | -8.08 ± 4.75 | -7.67 ± 5.31 |
Absent | 27 | -7.97 ± 4.77 | -7.28 ± 5.99 |
r
2
|
r
| 95% CI |
P
| |
---|---|---|---|---|
Age, years | 0.02 | -0.15 | -0.48 to 0.21 | 0.40 |
SAPS II at ICU admission | 0.001 | -0.03 | -0.38 to 0.32 | 0.85 |
Length of ICU stay before measurements, days | 0.002 | -0.05 | -0.30 to 0.40 | 0.77 |
Weight, kg | < 0.001 | -0.002 | 0.35 to 0.35 | 0.98 |
Height, cm | < 0.001 | 0.07 | -0.28 to 0.41 | 0.68 |
Body mass index, kg/cm2 | < 0.001 | 0.01 | -0.34 to 0.36 | 0.94 |
Body temperature, °C | 0.10 | -0.32 | -0.60 to 0.004 | 0.08 |
Plasma sodium concentration, mmol/L | 0.09 | 0.31 | -0.05 to 0.59 | 0.09 |
Plasma creatinine concentration, μmol/L | < 0.001 | -0.07 | -0.41 to 0.28 | 0.69 |
Plasma osmolality, mmol/kg | 0.02 | -0.16 | -0.48 to 0.20 | 0.39 |
Ultrafiltration, L | 0.05 | -0.22 | -0.53 to 0.14 | 0.23 |
Dialysate temperature, °C | < 0.001 | 0.01 | -0.34 to 0.36 | 0.94 |
Dialysate sodium concentration, mmol/L | 0.03 | 0.17 | -0.21 to 0.26 | 0.34 |
r
2
| r | 95% CI |
P
| |
---|---|---|---|---|
Age, years | 0.05 | -0.22 | -0.53 to 0.14 | 0.23 |
SAPS II at ICU admission | 0.18 | 0.43 | 0.08 to 0.67 | 0.01 |
Length of ICU stay before measurements, days | 0.08 | 0.29 | -0.06 to 0.58 | 0.10 |
Weight, kg | 0.01 | 0.10 | -0.25 to 0.44 | 0.44 |
Height, cm | 0.002 | 0.05 | -0.30 to 0.40 | 0.75 |
Body mass index, kg/cm2 | 0.006 | 0.08 | -0.27 to 0.42 | 0.64 |
Body temperature, °C | 0.01 | -0.12 | -0.45 to 0.24 | 0.51 |
Plasma sodium concentration, mmol/L | 0.04 | 0.20 | -0.16 to 0.53 | 0.26 |
Plasma creatinine concentration, μmol/L | 0.002 | 0.05 | -0.30 to 0.39 | 0.78 |
Plasma osmolality, mmol/kg | 0.04 | 0.21 | -0.15 to 0.52 | 0.26 |
Ultrafiltration, L | 0.001 | -0.04 | -0.39 to 0.31 | 0.81 |
Dialysate temperature, °C | 0.07 | -0.27 | -0.57 to 0.09 | 0.14 |
Dialysate sodium concentration, mmol/L | 0.02 | 0.15 | -0.21 to 0.48 | 0.40 |
Body cell mass and fat-free mass dynamics induced by hemodialysis
Discussion
Conclusions
Key messages
-
Estimation of body composition as FFM is subjected to many variations caused by injury and stress conditions in the ICU. BCM, the metabolically active part of FFM, is reported to be more specifically correlated to changes in nutritional status. Bedside estimation of BCM could help to provide more valuable markers of nutritional status and may promote understanding of metabolic consequences of energy deficit in ICU patients.
-
During acute hemodialysis, similar variations of ECW and ICW compartments occur in ICU patients whereas intradialytic variation of BCM is negligible and remains significantly less than FFM, suggesting substantial intercompartmental fluid shifts induced by hemodialysis.
-
In the case of sudden and massive fluid shifts, our study suggests that assessment of BCM should be preferred to FFM estimation in ICU patients.