The use of bio-electrical impedance analysis (BIA) to guide fluid management, resuscitation and deresuscitation in critically ill patients : a bench-to-bedside review

The impact of a positive fluid balance on morbidity and mortality has been well established. However, little is known about how to monitor fluid status and fluid overload. This narrative review summarises the recent literature and discusses the different parameters related to bio-electrical impedance analysis (BIA) and how they might be used to guide fluid management in critically ill patients. Definitions are listed for the different parameters that can be obtained with BIA; these include among others total body water (TBW), intracellular water (ICW), extracellular water (ECW), ECW/ICW ratio and volume excess (VE). BIA allows calculation of body composition and volumes by means of a current going through the body considered as a cylinder. Reproducible measurements can be obtained with tetrapolar electrodes with two current and two detection electrodes placed on hands and feet. Modern devices also apply multiple frequencies, further improving the accuracy and reproducibility of the results. Some pitfalls and conditions are discussed that need to be taken into account for correct BIA interpretation. Although BIA is a simple, noninvasive, rapid, portable, reproducible, and convenient method of measuring body composition and fluid distribution with fewer physical demands than other techniques, it is still unclear whether it is sufficiently accurate for clinical use in critically ill patients. However, the potential clinical applications are numerous. An overview regarding the use of BIA parameters in critically ill patients is given, based on the available literature. BIA seems a promising tool if performed correctly. It is non-invasive and relatively inexpensive and can be performed at bedside, and it does not expose to ionising radiation. Modern devices have very limited between-observer variations, but BIA parameters are population-specific and one must be aware of clinical situations that may interfere with the measurement such as visible oedema, nutritional status, or fluid and salt administration. BIA can help guide fluid management, resuscitation and de-resuscitation. The latter is especially important in patients not progressing spontaneously from the Ebb to the Flow phase of shock. More research is needed in critically ill patients before widespread use of BIA can be suggested in this patient population.The impact of a positive fluid balance on morbidity and mortality has been well established. However, little is known about how to monitor fluid status and fluid overload. This narrative review summarises the recent literature and discusses the different parameters related to bio-electrical impedance analysis (BIA) and how they might be used to guide fluid management in critically ill patients. Definitions are listed for the different parameters that can be obtained with BIA; these include among others total body water (TBW), intracellular water (ICW), extracellular water (ECW), ECW/ICW ratio and volume excess (VE). BIA allows calculation of body composition and volumes by means of a current going through the body considered as a cylinder. Reproducible measurements can be obtained with tetrapolar electrodes with two current and two detection electrodes placed on hands and feet. Modern devices also apply multiple frequencies, further improving the accuracy and reproducibility of the results. Some pitfalls and conditions are discussed that need to be taken into account for correct BIA interpretation. Although BIA is a simple, noninvasive, rapid, portable, reproducible, and convenient method of measuring body composition and fluid distribution with fewer physical demands than other techniques, it is still unclear whether it is sufficiently accurate for clinical use in critically ill patients. However, the potential clinical applications are numerous. An overview regarding the use of BIA parameters in critically ill patients is given, based on the available literature. BIA seems a promising tool if performed correctly. It is non-invasive and relatively inexpensive and can be performed at bedside, and it does not expose to ionising radiation. Modern devices have very limited between-observer variations, but BIA parameters are population-specific and one must be aware of clinical situations that may interfere with the measurement such as visible oedema, nutritional status, or fluid and salt administration. BIA can help guide fluid management, resuscitation and de-resuscitation. The latter is especially important in patients not progressing spontaneously from the Ebb to the Flow phase of shock. More research is needed in critically ill patients before widespread use of BIA can be suggested in this patient population

Techniques of Measuring Plasma Volume Changes in Pregnancy

Restricted plasma volume prior to and during pregnancy has been clinically linked to placental syndrome - that is to say, gestational maternal hypertensive sequellae on the one hand and fetal growth restriction on the other. Asmost of the plasma volume is localized at the venous side of the vascular system, when having a healthy heart, plasma volume largely reflexes venous reserve capacity to balance alterations in arterial needs. Plasma volume can be measured directly by bleeding, obviously not applicable to human research, or indirectly using dilution or indicator dilution techniques. The latter two techniques require first order kinetics. Moreover, the indicator must be traceable and measurable. Finally, when used in pregnancy, they must be safe for both mother and fetus. More novel bioelectrical impedance techniques claim to be able to estimate whole body extracellular fluid content. The reliability to assess plasma volume, as part of the extracellular volume, by bioimpedance, remains to be elucidated, but when consistent and precise, it has the potency to be highly applicable in daily care

Plasma Volume Changes in Pregnancy

Under healthy conditions, only one-third of the plasma volume is located in the arterial compartment, whereas the remainder is located in the venous compartment to balance increased arterial demands. In normotensive formerly preeclamptic women, about half have low plasma volume, a condition paralleled by reduced venous compliance, blunted responsiveness to orthostatic stress and consistently higher sympathetic tone. Low plasma volume therefore seems to represent reduced venous reserve capacity. Functionally, prepregnancy low plasma volume predisposes to early-pregnancy circulatory maladaptation; clinically, it relates to increased risk on recurrent hypertensive disease, growth restriction and preterm birth. Modulation of the plasma volume compartment may therefore reduce the risk of recurrent gestational hypertensive sequellae in women with prepregnancy reduced plasma volume

Hepatic hemodynamics and fetal growth: a relationship of interest for further research.

It is well known that hepatic hemodynamics is an important physiologic mechanism in the regulation of cardiac output (CO). It has been reported that maternal cardiac output relates to neonatal weight at birth.In this study, we assessed the correlation between maternal hepatic vein Doppler flow parameters, cardiac output and neonatal birth weight.Healthy women with uncomplicated second or third trimester pregnancy attending the outpatient antenatal clinic of Ziekenhuis Oost-Limburg in Genk (Belgium), had a standardized combined electrocardiogram-Doppler ultrasound with Impedance Cardiography, for measurement of Hepatic Vein Impedance Index (HVI  =  [maximum velocity - minimum velocity]/maximum velocity), venous pulse transit time (VPTT  =  time interval between corresponding ECG and Doppler wave characteristics) and cardiac output (heart rate x stroke volume). After delivery, a population-specific birth weight chart, established from a cohort of 27000 neonates born in the index hospital, was used to define customized birth weight percentiles (BW%). Correlations between HVI, VPTT, CO and BW% were calculated using Spearman's ρ, linear regression analysis and R2 goodness of fit in SPSS 22.0.A total of 73 women were included. There was a negative correlation between HVI and VPTT (ρ = -0.719, p < 0.001). Both HVI and VPTT correlated with CO (ρ = -0.403, p < 0.001 and ρ = 0.332, p < 0.004 resp.) and with BW% (ρ =  -0.341, p < 0.003 and ρ = 0.296, p < 0.011 resp.).Our data illustrate that the known contribution of hepatic hemodynamics in the regulation of cardiac output is also true for women with uncomplicated pregnancies. Our study is the first to illustrate a potential link between maternal hepatic hemodynamics and neonatal birth weight. Whether this link is purely associative or whether hepatic vascular physiology has a direct impact on fetal growth is to be evaluated in more extensive clinical and experimental research

Maternal venous hemodynamics in gestational hypertension and preeclampsia

BACKGROUND: To evaluate characteristics of venous hemodynamics, together with cardiac and arterial function, in uncomplicated pregnancies (UP), non-proteinuric gestational hypertension (GH) and preeclampsia (PE). METHODS: In this observational cross-sectional study, venous hemodynamics was assessed using a standardised protocol for combined electrocardiogram (ECG)-Doppler ultrasonography, together with a non-invasive standardised cardiovascular assessment using impedance cardiography (ICG) in 13 women with UP, 21 with GH, 34 with late onset PE ≥ 34 w (LPE) and 22 with early onset PE 15% higher (P ≤ .010) in LPE and EPE, as compared to GH and UP. Next to this, >30% lower values for VI and ACI (P ≤ .029), and > 15% lower values for APTT (P ≤ .012) were found in GH, LPE and EPE, as compared to GH. CONCLUSION: In comparison to UP, similar abnormalities of central arterial function and APTT were found in GH, EPE and LPE. Proteinuria of LPE and EPE was associated with increased RIVI, this was not observed in GH.status: publishe

Diabetes mellitus en metabole bijwerkingen bij minderjarigen behandeld met het antipsychoticum risperidon: follow-up tot drie jaar

This study reports the follow-up of 66 minors (12-17 years old) exposed to risperidone, regardless of their diagnosis. The rationale of this investigation was that the stringent in- and exclusion criteria of most current publications include only 5% of the patients of this age group. Thus, generalizing those findings remains highly questionable. Moreover, most studies are short term (≤ 12 weeks) and thus lack predictive power in the long term. 66 patients were selected out of the followup database based on the next criteria: exposure to risperidone, no concomitant use of other antipsychotics, and consultation at least once for follow-up. Diagnosis, off-label use or the use of other psychotropics were no exclusion criteria. The biometric data, the lipids, and the glucose metabolism were monitored according to the metabolic protocol. No cases of increased glycemia or diabetes mellitus were observed. Still, a significant increase in weight, abdominal circumference, diastolic blood pressure and the prevalence of lipid disorders was noticed. Regardless of the absence of the direct effects on glycemia, one should use risperidone cautiously and keep monitoring for diabetes mellitus as indirect factors, like weight gain or an increase in abdominal circumference, might contribute to the metabolic side-effects.SCOPUS: re.jinfo:eu-repo/semantics/publishe