Reference values and determinants for handgrip strength in healthy subjects.

BACKGROUND & OBJECTIVES: To determine reference values and associated factors for handgrip strength among healthy adults. METHODS: Three hundred well nourished (SGA category A) subjects were studied, aged 18-90 years. Handgrip strength (HS) was determined using a hand dynamometer. Adductor pollicis muscle (APM) thickness and other anthropometric variables were also measured. Results were analyzed according to gender and age group. We carried out multiple linear regression in order to identify significant determinants of handgrip strength. RESULTS: HS is significantly associated with gender and decreases after age 60 years (p<0.001). Different reference values for each gender and age category are presented, for both dominant (DHS) and non-dominant hands (NDHS). APM showed a strong correlation with HS (R(2)=0.71 and 0.70, for DHS and NDHS, respectively). This association remained significant after adjustment for other variables such as gender, age and body mass index. CONCLUSION: Reference values are needed to allow the use of HS as a muscular function assessment tool. Values should be stratified by gender and age group. The combined use of HS and APM may be useful as a method for nutritional assessment.

Associação entre ângulo de fase, PRISM I e gravidade da sepse / Association between phase angle, PRISM I and sepsis severity

JUSTIFICATIVA E OBJETIVOS: Ângulo de fase (AF) é a diferença entre a voltagem e a corrente e pode ser usado como indicador de massa celular corporal. Estudos clínicos mostram que baixos AF estão associados com morbidade e mortalidade em pacientes críticos. O objetivo deste estudo foi conhecer a relação entre AF e o escore pediátrico de risco de mortalidade (PRISM I) em pacientes pediátricos sépticos críticos, associando esse indicador c om a gravidade da sepse. MÉTODO: Estudo transversal realizado na Unidade de Terapia Intensiva (UTI) Pediátrica do Instituto Fernandes Figueira. Os pacientes foram caracterizados de acordo com faixa etária, sexo, gravidade da sepse, etiologia da insuficiência respiratória, escore de PRISM I, grau de disfunção de múltiplos órgãos e sistemas (DMOS). A análise de bioimpedância elétrica (BIA) foi realizada em todos os pacientes e, através da razão dos valores de reactância (Xc) e resistência (R), foi calculado o AF (AF = arco-tangente da reactância/resistência x 180º /Pi). RESULTADOS: Foram avaliados 75 pacientes, sendo 68 (90,7 por cento) com sepse. A incidência de choque séptico foi 39,7 por cento, sepse grave 42,6 por cento e sepse 17,6 por cento. Não houve diferença estatística significativa entre as médias de ângulo de fase e as categorias de PRISM I, porém observou-se uma relação inversa entre os valores de AF e as categorias de PRISM I, DMOS e tempo de internação. Os valores mais baixos de AF (1,5º-2,2º) foram observados no maior escore de PRISM I (> 30 por cento). CONCLUSÕES: Os pacientes pediátricos críticos apresentaram baixos valores de angulo de fase, portanto deve ter a sua importância prognóstica estudada.

BACKGROUND AND OBJECTIVES: Phase angle (PA) is the difference between voltage and current and can be used as an indicator of body cell mass. Clinical studies show that low phase angle is associated with morbidity and mortality of critical patients. The purpose of this study was to know the relation between phase angle and the Pediatric Risk of Mortality I (PRISM I) score, associating this score with the severity of sepsis. METHODS: A transversal study was performed at the Pediatric Intensive Care Unit (PICU) in Instituto Fernandes Figueira. The patients were classified according to age, gender, sepsis severity, cause of respiratory failure, PRISM I score, multiple organ dysfunction syndromes (MODS). Electrical bioimpedance analysis (BIA) was performed in all patients. Phase angle was calculated directly from reactance (Xc) and resistance (R). AF = arc-tangent reactance/resistance x 180º/Pi. RESULTS: 75 patients (68 septic) were evaluated. The incidence of septic shock was 39.7 percent, severe sepsis 42.6 percent and sepsis 17.6 percent. There was no significative statistical difference between the mean values of BIA and the categories of PRISM I, MODS, or the length of stay the PICU. The PA's lowest values (1.5º-2.2º) were associated to the greatest PRISM's scores (> 30 percent). CONCLUSIONS: Pediatric critical patients show low phase angle values, which might have prognostic implication.

[Association between phase angle, PRISM I and sepsis severity]. / Associação entre ângulo de fase, PRISM I e gravidade da sepse.

BACKGROUND AND OBJECTIVES: Phase angle (PA) is the difference between voltage and current and can be used as an indicator of body cell mass. Clinical studies show that low phase angle is associated with morbidity and mortality of critical patients. The purpose of this study was to know the relation between phase angle and the Pediatric Risk of Mortality I (PRISM I) score, associating this score with the severity of sepsis. METHODS: A transversal study was performed at the Pediatric Intensive Care Unit (PICU) in Instituto Fernandes Figueira. The patients were classified according to age, gender, sepsis severity, cause of respiratory failure, PRISM I score, multiple organ dysfunction syndromes (MODS). Electrical bioimpedance analysis (BIA) was performed in all patients. Phase angle was calculated directly from reactance (Xc) and resistance (R). AF = arc-tangent reactance/resistance x 180º/Pi. RESULTS: 75 patients (68 septic) were evaluated. The incidence of septic shock was 39.7%, severe sepsis 42.6% and sepsis 17.6%. There was no significative statistical difference between the mean values of BIA and the categories of PRISM I, MODS, or the length of stay the PICU. The PA's lowest values (1.5º-2.2º) were associated to the greatest PRISM's scores (> 30%). CONCLUSIONS: Pediatric critical patients show low phase angle values, which might have prognostic implication.

Bioelectrical impedance analysis: population reference values for phase angle by age and sex.

BACKGROUND: Phase angle is an indicator based on reactance and resistance obtained from bioelectrical impedance analysis (BIA). Although its biological meaning is still not clear, phase angle appears to have an important prognostic role. OBJECTIVE: The aim of this study was to estimate population averages and SDs of phase angle that can be used as reference values. DESIGN: BIA and other methods used to evaluate body composition, including hydrodensitometry and total body water, were completed in 1967 healthy adults aged 18-94 y. Phase angle was calculated directly from body resistance and reactance, and fat mass (FM) was estimated from the combination of weight, hydrodensitometry, and total body water by using the 3-compartment Siri equation. Phase angle values were compared across categories of sex, age, body mass index (BMI), and percentage FM. RESULTS: Phase angle was significantly (P < 0.001) smaller in women than in men and was lower with greater age (P < 0.001). Phase angle increased with an increase in BMI and was significantly inversely associated with percentage fat in men. Phase angle was significantly predicted from sex, age, BMI, and percentage FM in multiple regression models. CONCLUSIONS: Phase angle differs across categories of sex, age, BMI, and percentage fat. These reference values can serve as a basis for phase angle evaluations in the clinical setting.

Bioelectric impedance and individual characteristics as prognostic factors for post-operative complications.

BACKGROUND AND AIMS: Malnutrition increases morbidity and mortality in surgical patients, and for this reason, several nutritional markers have been used as prognostic tools to identify surgical patients under a higher risk to develop complications in post-operative period. Few studies show the impact of nutritional markers after controlling for others variables, such as age and severity of disease. A new method, bioelectric impedance analysis (BIA), and its parameter, phase angle, have been described as a prognostic tool in several clinical situations, but they have never been studied in surgical population. The objective of this work is to assess the importance of nutritional variables and parameters from BIA as predictors of post-operative complications in a multivariable regression model. METHODS: The nutritional status of 225 adult patients scheduled to undergo gastrointestinal surgery was assessed by several methods, including bioelectric impedance analysis and subjective global assessment. Potential confounding factors were also studied. Patients were screened for post-operative complications until hospital discharge. RESULTS: Weight loss greater than 10%, subjective global assessment, nutritional risk assessment, ECM/BCM ratio and phase angle (from BIA) were the prognostic factors significantly associated with post-operative complications in the crude analysis. After adjusting for sex, age, marital status, tumors and pre-operative infections, only phase angle remained as a prognostic factor (RR=4.3; CI95% 1.6-11.8 for phase angle <-0.8 sd), while the other nutritional variables lost their association with post-operative complications. CONCLUSION: Phase angle remains as an important prognostic factor for postoperative complications, even after adjusting for other individual predictors and confounders. Its utility in the identification of patients eligible for nutritional therapy has now to be evaluated.

Bioelectrical impedance analysis in clinical practice: a new perspective on its use beyond body composition equations.

PURPOSE OF REVIEW: The bioelectrical impedance analysis is not a direct method for estimating body composition. Its accuracy depends on regression equations, and recent papers have suggested that this approach should not be used in several clinical situations. Another option is to obtain information about the electrical properties of tissues by using raw bioelectrical impedance measurements, resistance and reactance. They can be expressed as a ratio (phase angle) or as a plot (bioelectrical impedance vector analysis). This review describes their use in clinical practice. RECENT FINDINGS: The phase angle changes with sex and age. It is described as a prognostic tool in many clinical situations. There are some controversies about considering it as a nutritional marker. Studies in burn victims and sickle-cell disease corroborate its ability to evaluate cell membrane function. Bioelectrical impedance vector analysis allows a semi-quantitative estimation of body composition from information from tissue hydration and soft-tissue mass in a plot. It can be used in healthy individuals or patients, for a population or individual evaluation of fluid imbalance or an assessment of soft-tissue mass. It has also been used as a prognostic tool in dialysis and cancer patients. SUMMARY: The phase angle can be considered a global marker of health, and future studies are needed to prove its utility in intervention studies. Bioelectrical impedance vector analysis has increased its utility in clinical practice, even when the equations may be inaccurate for body composition analysis.

Can bioelectrical impedance analysis identify malnutrition in preoperative nutrition assessment?

OBJECTIVE: Malnutrition is characterized by changes in cellular membrane integrity and alterations in fluid balance, both of which can be detected by bioelectrical impedance analysis (BIA). We investigated whether BIA-measured variables could detect malnutrition, as defined by the Subjective Global Assessment (SGA), in preoperative surgical patients. METHODS: We prospectively evaluated 279 patients hospitalized for elective gastrointestinal surgery during the first 72 h after admission. BIA estimates were used to derive body cell mass, ratio of extracellular mass to body cell mass, and phase angle. Malnutrition diagnosed with these measures was compared with the SGA score. Receiver operating characteristic curves also were formulated to explore alternative cutoff points for one measure, phase angle. RESULTS: A linear trend for means across SGA categories was found for all indicators used, except percentage of body cell mass. However, there was only fair overall agreement between SGA and BIA estimates. The receiver operating characteristic curves for phase angle suggested that the test was too sensitive or too specific. No alternative cutoff points resulted in suitable tests that could provide an alternative to SGA. CONCLUSIONS: Although not in close agreement with SGA, the results suggested that there are some alterations in tissue electrical properties with malnutrition that can be detected by BIA. New cutoff points may be needed for application of BIA as a complementary method in the nutrition assessment of surgical patients.