Invasive dynamic electrical impedance myography during 100 s of moderate contraction in rats' gastrocnemius muscle.

GOAL: The present study aimed to investigate the behavior of dynamic electrical impedance myography (dEIM) signals during a 100-s period of the dynamic contraction of Wistar rats' gastrocnemius evoked by electrical stimulation and to link the variations in bioimpedance with muscular energy systems. METHODS: Muscle contraction used 30% of the maximum muscular force and persisted for 100 s, along which dynamic bioimpedance signals were acquired. Based on the bioimpedance signals, two parameters, ΔZc and ΔZpc, were calculated to allow the analysis of their changes with the energy systems that supplied adenosine triphosphate (ATP) to the muscle. ΔZc indicated the variation of impedance of a twitch cycle compared to the values observed during the rest period preceding the cycle, and ΔZpc indicated slow bioimpedance variations compared to the values obtained during the rest period. RESULTS: The results indicated that ΔZc followed the force behavior, achieving a change rate of ∼14%. This parameter was associated with instantaneous impedance changes owing to the occurrence of each twitch. CONCLUSION: Although the findings of this study were linked to energy system processes, future studies are required for improving the understanding of the underlying mechanisms involved in dEIM. SIGNIFICANCE: The results contributed to understanding the relation of energy systems that supply ATP to the muscles with dEIM variations that occurred during muscle activity.

Effect of dietary buriti oil on the quality, fatty acid profile and sensorial attributes of lamb meat.

Forty crossbred (Santa Ines × Dorper) male lambs were used to investigate the effect of dietary buriti oil (BOIL) intake on meat quality, fatty acid (FA) composition and sensory attributes. A completely randomized design with five BOIL intake levels (0, 12, 24, 36 and 48 g/kg DM) was used. Increasing dietary BOIL intake linearly reduced the DMI, slaughter weight, cooking loss, shear force, yellowness, 16:0, c9-18:1 FA concentrations, and the delta-9-desaturase activity index computed using c9-16:1 and 16:0 as product and substrate pair, cis-MUFA and Æ©MUFA/Æ©SFA ratio of lamb meat (P ≤ 0.05); however, increasing dietary BOIL intake quadratically increased the energy intake, lipid content and linearly increased the total FA intake, chroma, collagen, total BI, 18:0, 20:3n-6 concentration and sensory attributes of lamb meat (P ≤ 0.05), without affecting health indexes regarding fat consumption. BOIL addition at levels above 24 g/kg DM in lamb diet reduces growth, however, improves tenderness, flavor and "goat" aroma intensity and slightly changes meat FA levels, promoting better acceptance by panelists.

Progressive inclusion of pearl millet herbage as a supplement for dairy cows fed mixed rations: Effects on methane emissions, dry matter intake, and milk production.

The inclusion of grazing in dairy feeding systems can improve animal welfare and reduce feed costs and labor for animal care and manure management. This work aimed to evaluate the effects of including pearl millet herbage (Pennisetum glaucum 'Campeiro') as a supplement for dairy cows fed total mixed rations (TMR). The treatments included 100% TMR offered ad libitum (control, TMR100), 75% TMR ad libitum intake + access to grazing of a pearl millet pasture between the morning and afternoon milkings (7 h/d; pTMR75), and 50% TMR ad libitum intake + access to grazing of a pearl millet pasture between the morning and afternoon milkings (7 h/d; pTMR50). Nine multiparous Holstein and F1 Jersey × Holstein cows were distributed in a replicated 3 × 3 Latin square design with 3 periods of 21 d (a 16-d adaptation period and a 5-d measurement period). Cows in the TMR75 and TMR50 groups strip-grazed a pearl millet pasture with pre- and postgrazing sward height targets of 60 and 30 cm, respectively. The herbage dry matter intake (DMI) increased with decreasing mixed ration supplies, and the total DMI decreased linearly from 19.0 kg/d in the TMR100 group to 18.0 kg/d in the pTMR50 group. Milk production decreased linearly from 24.0 kg/d in the TMR100 group to 22.4 kg/d in the pTMR50 group, and energy-corrected milk (ECM) production decreased linearly from 26.0 kg/d to 23.6 kg/d. Enteric methane (CH4) emissions decreased linearly from 540 g/d in the TMR100 group to 436 g/d in the pTMR50 group, and CH4 yields (g/kg of DMI) tended to decrease linearly. The CH4 intensity was similar between treatments, averaging 20 g of CH4/kg of ECM. The inclusion of pearl millet herbage in the dairy cow diets decreased the total DMI and milk production to a small extent without affecting CH4 intensity (g/kg of ECM).

Invasive electrical impedance myography at different levels of contraction of gastrocnemius muscle of rat.

Electrical impedance myography (EIM) is as an experimental technique that associates muscle impedance with muscular activity. Changes in muscle impedance during contraction occur mainly due to changes in the morphological and physiological characteristics of muscles that lead to different impeditivities in comparison with the resting condition. There is no consensus on the details of muscular impedance during muscle activity. EIM measurements on humans are also influenced by factors such as the electrode-skin interface, layers of skin and fat, and the connective tissue that can generate undesirable effects in the impedance signal. These effects can be avoided if EIM measurements are carried out directly on the muscle by using the models of animals. This study investigates changes in the EIM signal in the gastrocnemius muscles of Wistar rats during different levels of muscular contraction. In vivo experiments were conducted on 19 male rats. The muscle was exposed, fixed on a load cell, and electrically stimulated to evoke different levels of muscle contraction. Signals of the components of impedance were analyzed against the muscular force signal. The results show moderate correlations (p < 0.05) among the impedance-related parameters of resistance (r = -0.76), reactance (r = 0.57), and phase (r = 0.53). In addition to providing an experimental protocol for the invasive collection of data on electrical impedance to minimize problems associated with surface electrodes, this study shows that of the components of impedance, resistance is most affected by the intensity of muscular contractions and that morphological changes influence impedance mainly at low intensities.

Direct detection of Salmonella from poultry samples by DNA isothermal amplification.

1. Salmonellosis is one of the most important diseases in public health and it is usually associated with poultry product consumption. This study aimed to validate rapid methods to detect Salmonella spp. from poultry samples. 2. A DNA isothermal amplification method, previously developed for other matrices, was applied for the specific detection of Salmonella spp. from various samples, including poultry tissues, drag and boot swabs, faeces and feed. A new procedure was validated with Salmonella spp. serotypes and isolates from other enteric bacterial species, as well as naturally contaminated poultry samples. 3. The study demonstrated the successful development and implementation of a procedure, including a DNA isothermal amplification method, for the detection of Salmonella spp. directly from tissues, drag and boot swabs, faeces and feed. The whole procedure can be performed in less than 24 hours and it has been successfully used in a veterinary diagnostic laboratory.

Development of hybrid microspheres for assessment of multiphase processes.

This work presents a new technique for the synthesis of particles satisfying the conditions of several multiphase suspensions. It consists of manufacturing PMMA_La2O3 hybrid microspheres through suspension polymerization first and then submitting the beads to neutron activation. It was found that the fractional mass of the filler La2O3 in the beads can be greater that 60% using this technique. The results and other properties of the particles clearly indicate that the technique is effective to produce particles for several RPT applications.

Molecular detection of Salmonella serovars Enteritidis, Heidelberg and Typhimurium directly from pre-enriched poultry samples.

1. Salmonella is one of the most important pathogens in public health and it is usually associated with food-borne diseases. Salmonella serovars Enteritidis and Typhimurium are widespread in the world with outbreaks frequently associated with consumption of poultry products; furthermore, there is an increasing public health concern with the wide dissemination of the serovar Heidelberg in poultry flocks. 2. The aim of the experiment was to develop and to validate rapid methods to detect Salmonella serovars Enteritidis, Typhimurium, and Heidelberg by real-time PCRs and test isolates from pre-enriched poultry samples. 3. Three real-time PCRs were developed and used in combination to detect the serovars Enteritidis, Typhimurium and Heidelberg. These assays were validated by the analysis of 126 Salmonella isolates, eight other enteric bacterial species and 34 naturally contaminated poultry samples after pre-enrichment with buffered peptone water (BPW). 4. Real-time PCRs detected the isolates of the most important poultry serovars (Enteritidis, Typhimurium and Heidelberg) with 100% inclusivity and exclusivity in each assay. The PCR identified monophasic variants of the serovars Typhimurium and Heidelberg. All PCRs were validated in detecting these specific serovars directly from pre-enriched poultry samples. The whole analytical procedure was performed in less than 24 h in a veterinary diagnostic laboratory.

Lactate threshold by muscle electrical impedance in professional rowers.

Lactate threshold (LT) is one of the physiological parameters usually used in rowing sport training prescription because it indicates the transitions from aerobic to anaerobic metabolism. Assessment of LT is classically based on a series of values of blood lactate concentrations obtained during progressive exercise tests and thus has an invasive aspect. The feasibility of noninvasive LT estimative through bioelectrical impedance spectroscopy (BIS) data collected in thigh muscles during rowing ergometer exercise tests was investigated. Nineteen professional rowers, age 19 (mean) ± 4.8 (standard deviation) yr, height 187.3 ± 6.6 cm, body mass 83 ± 7.7 kg, and training experience of 7 ± 4 yr, were evaluated in a rowing ergometer progressive test with paired measures of blood lactate concentration and BIS in thigh muscles. Bioelectrical impedance data were obtained by using a bipolar method of spectroscopy based on the current response to a voltage step. An electrical model was used to interpret BIS data and to derive parameters that were investigated to estimate LT noninvasively. From the serial blood lactate measurements, LT was also determined through Dmax method (LTDmax). The zero crossing of the second derivative of kinetic of the capacitance electrode (Ce), one of the BIS parameters, was used to estimate LT. The agreement between the LT estimates through BIS (LTBIS) and through Dmax method (LTDmax) was evaluated using Bland-Altman plots, leading to a mean difference between the estimates of just 0.07 W and a Pearson correlation coefficient r = 0.85. This result supports the utilization of the proposed method based on BIS parameters for estimating noninvasively the lactate threshold in rowing.

Detection of questionable occlusal carious lesions using an electrical bioimpedance method with fractional electrical model.

This in vitro study evaluated the diagnostic performance of an alternative electric bioimpedance spectroscopy technique (BIS-STEP) detect questionable occlusal carious lesions. Six specialists carried out the visual (V), radiography (R), and combined (VR) exams of 57 sound or non-cavitated occlusal carious lesion teeth classifying the occlusal surfaces in sound surface (H), enamel caries (EC), and dentinal caries (DC). Measurements were based on the current response to a step voltage excitation (BIS-STEP). A fractional electrical model was used to predict the current response in the time domain and to estimate the model parameters: Rs and Rp (resistive parameters), and C and α (fractional parameters). Histological analysis showed caries prevalence of 33.3% being 15.8% hidden caries. Combined examination obtained the best traditional diagnostic results with specificity = 59.0%, sensitivity = 70.9%, and accuracy = 60.8%. There were statistically significant differences in bioimpedance parameters between the H and EC groups (p = 0.016) and between the H and DC groups (Rs, p = 0.006; Rp, p = 0.022, and α, p = 0.041). Using a suitable threshold for the Rs, we obtained specificity = 60.7%, sensitivity = 77.9%, accuracy = 73.2%, and 100% of detection for deep lesions. It can be concluded that BIS-STEP method could be an important tool to improve the detection and management of occlusal non-cavitated primary caries and pigmented sites.

Uso off label de medicamentos em crianças e adolescentes / Off label use of medicines in children and adolescents

De acordo com a definição de uso off label (ou seja, quando um medicamento é indicado ao paciente de maneira diferente daquela que foi autorizada pelo órgão regulatório em um país), o objetivo deste estudo foi identificar a presença desse tipo de prescrição, diferente da recomendação aprovada pela FDA e ANVISA, para crianças e adolescentes do nascimento até 18 anos. Para isso, foram analisadas as solicitações de medicamentos feitas por ordem judicial ao CEMEPAR/ SESA-PR (Centro de Medicamentos do Paraná / Secretaria de Saúde do Paraná) no ano de 2008. Foram impetradas 934 solicitações, sendo que, destas, 142 (15,20%) tinham indicação diferente da recomendada quando comparadas com informações da FDA, além de outras 112 (12%) quando comparadas com informações da ANVISA. Das prescrições analisadas, 22,54% estavam relacionadas à faixa etária diferente da recomendada de acordo com a FDA e 26,79% de acordo com a ANVISA. Considerando-se a importância do tema para a saúde pública, ressalta-se a necessidade da divulgação de informações e regulamentações sobre o assunto no Brasil.

Noting the definition of off-label use (ie, when a drug is indicated for a patient with a condition for which it has not been authorized by the regulatory agency of the country), the aim of this study was to identify the presence of this type of prescription, at variance with the recommendations of the FDA and (in Brazil) ANVISA, for children and adolescents from birth up to 18 years of age. To this end, the requests for drugs made by court order to CEMEPAR / SESA-PR (Paraná State Medicine Center) in 2008 have been analyzed. A total of 934 requests were filed, out of which 142 (15.20%) contained indications other than the recommended ones, according to information from FDA, and another 112 (12%) indicated a use conflicting with information from ANVISA. Out of the prescriptions analyzed, 22.54% were for patients whose age differed from the range recommended by FDA and 26.79% from the ANVISA range. Considering the importance of the issue to public health, the study highlights the need to spread information on the regulations on these practices in Brazil.

Acompanhamento farmacoterapêutico a pacientes usuários de enfuvirtida / Pharmaceutical care of patients treated with enfuvirtide

Enfuvirtida é um inibidor de fusão que interfere nascélulas com a penetração do vírus HIV. Sua aplicaçãoé feita por via subcutânea, o que provoca efeitos nocivos no local da aplicação. Os pacientes em uso deenfuvirtida deixam de usá-la constantemente, sugerindo uma baixa adesão devido às diferentes reações quepodem ocorrer com a administração subcutânea do medicamento. O objetivo da pesquisa, portanto, foi avaliar a relação entre a adesão e o acompanhamento farmacoterapêutico a pacientes usuários de enfuvirtida. A pesquisa foi realizada com pacientes com AIDS emuso de enfuvirtida, no CRE Metropolitano. Dados do perfil clínico e sócio-econômico foram coletados por meio de entrevistas. As entrevistas foram agendadas, mensalmente, para verificar a adesão do paciente ao uso de enfuvirtida durante os meses de setembro de 2008 a junho de 2009. Algumas peculiaridades do uso da forma farmacêutica injetável e a posologia de duas vezes por dia são identificadas como fatores limitantes para o tratamento. A maioria dos pacientes reconhece a importância do tratamento. Porém, cerca de 40%relatam dificuldades na aplicação e são intolerantes às reações adversas causadas pela aplicação subcutânea. Cerca de 33% deles, devido à assistência que estão recebendo, ainda esperam a liberação de novos medicamentos para a troca de esquema sem interrompero uso de enfuvirtida.

Enfuvirtide is a fusion inhibitor that interferes with the penetration of HIV into cells. It is injected subcutaneously, causing adverse side effects at the application site. Patients using enfuvirtide often discontinue the treatment, suggesting low compliance due to the various reactions provoked by the subcutaneous administration of the drug. The objective of this research was thus to assess the connection between pharmacotherapeutic follow-up and adherence of patients to the enfuvirtide regimen. The survey was conducted on AIDS patients prescribed enfuvirtide at a Metropolitan CRE (Brazilian Specialty Public Health Center). Data on the clinical profile and socioeconomic conditions were collected by interview. The interviews were scheduled monthly, to monitor patient adherence to the enfuvirtide treatment over the period from September 2008 to June 2009. Some peculiarities of the use of the injectable pharmaceutical form and the twice-daily injections are identified as limiting factors for the treatment. Most patients recognized its importance, but about 40% reported difficulties in injecting the drug and were intolerant of the adverse reactions caused by subcutaneous administration. About 33% of them, due to the accompaniment they are receiving, are still awaiting the release of new medicines so as to change their treatment plan without interrupting the use of enfuvirtide.

Substituições de esquemas antirretrovirais no Estado do Paraná / Changes of antiretroviral regimen in Paraná

O controle da AIDS no Brasil apresenta resultados favoráveis devido à política seguida pelo Ministério da Saúde que dá ênfase conjunta, na prevenção e atenção à doença com o fornecimento gratuito dos medicamentos. O Ministério da Saúde através do Programa Nacional de DST/AIDS (PN-DST/AIDS) seleciona e compra os medicamentos antirretrovirais (ARVs) e os distribui aos estados. O PN-DST/AIDS distribui 17 medicamentos ARV, em 29 formas farmacêuticas a todos os estados do Brasil. No Paraná, o Centro de Medicamentos do Paraná (CEMEPAR) é o responsável pelo recebimento desses e pela distribuição às 36 Unidades Dispensadoras de Medicamentos (UDMs). Foi realizado um levantamento no estado do Paraná/CEMEPAR no período de janeiro a dezembro/2008 sobre as solicitações enviadas para cadastro de início de tratamento e/ou troca de esquema ARV onde foi observado que 70,56% referiu-se à troca de esquema e, também, que das 5.992 solicitações enviadas, 8,34% (500) apresentavam algum tipo de erro. A pesquisa demonstrou a importância da análise das solicitações, que é um serviço diferenciado realizado pelo estado do Paraná onde foi possível verificar a alta ocorrência de troca de esquemas e a necessidade de um acompanhamento farmacoterapêutico para melhorar a adesão ao tratamento.

The Aids control program in Brazil has been achieving favorable results, owing to the policy adopted by the Ministry of Health, which gives emphasizes both prevention and care for the disease, with the free distribution of medications. The Ministry of Health selects and buys all antiretroviral medications through the National Program DST/AIDS (PN-DST/AIDS) and distributes 17 ARV medications in 29 pharmaceutical forms to all states of Brazil. In Parana State, CEMEPAR (Medicine Center of Parana), is responsible for receiving these medications and redistributing them to the 36 Medicine Distribution Units (UDMs). All requests to change ARV regimen or to start ARV treatment are sent to CEMEPAR for analysis and authorization. An analysis was made of the requests sent to CEMEPAR from January to December 2008 by all of the UDMs where the patients received their medications and it was found that 70.56% were for changes of ARV regimen and that, in 8.34% of all requests, there was some kind of mistake. The survey demonstrated the importance of analyzing the requests, which is a specific service provided by the state of Parana, in which it was possible to observe the high frequency of changes of treatment schemes and a need for pharmacotherapeutic guidance, to improve patient adherence to the treatment.

Comparison of two bioimpedance spectroscopy techniques in the assessment of body fluid volumes.

The present study aimed to compare the estimates of body liquid volumes performed by two bioimpedance spectrometry techniques. One based on a step response technique (BIS-PEB) and second one based on multifrequency Xitron Hydra 4200 equipment (Xitron Technologies, San Diego, CA, USA). The convenience sample was initially composed of 422 students from a military parachuting course of the Brazilian Army. From such sample 42 male students were randomly selected to be evaluated during three weeks. The anthropometrical characteristics of the sample can be summarized as: 25.18 +/- 4.10 years old; weight equals of 76.77 +/- 7.84 kg; height equals to 174.96 +/- 5.67 cm; body mass index (BMI) equal to 25.05 +/- 2.11 kg m(-2). Bland-Altman graphics were used to compare the two methods in what concerns to estimate of extracellular fluid (ECF), intracellular fluid (ICF), and total body water (TBW). One can observe that the estimates of the two techniques present a good correlation, especially in the case of ECF (r = 0.975). The present study indicates that BIS-PEB technique associated with De Lorenzo equation can supply noninvasive estimates of body fluid volumes comparable to Xitron Hydra 4200 equipment.

Objective assessment of knee osteroarthritis in parachuters by bioimpedance spectroscopy.

The aim of the present study was to derive an objective and noninvasive assessment of osteoarthritis of the knee joint by bioimpedance spectrocopy (BIS). The study was performed in Brazilian Military Parachuters and intends to contribute to the improvement of the early diagnosis of joint degeneration. Twelve male volunteers (24 knee joints) participated in the study. A novel index (ID) to assess the disease was proposed from the raw bioimpedance parameter. This index was compared with a subjective rating (Dejour scale) performed by 3 therapists. The results indicated that the values of ID were significantly different (p0.001) between the control group (class 1 of Dejour) and the pathological group (class 2 or higher). A Spearman correlation of -0.81 between the values of ID and the therapists rating was detected. Despite the need of increasing the sample size, the novel technique seems to be capable of supplying an objective and non-invasive tool for helping the diagnosis of the knee osteoarthritis.

A programmable system of functional electrical stimulation (FES).

The development of a novel system intended to perform functional electrical stimulation (FES) is presented. A virtual instrument developed in Labview communicates with a PC through USB and controls the hardware compound of analog and digital circuits. The block diagram of the hardware and the main characteristics of the virtual instrument are presented, as well the results of the electrical safety tests and the errors associated to the programmed and real values of the amplitude, pulse width and frequency of the output current. The results point the equipment can be used in the therapy of paraplegic patients maintaining safety limits reported in the literature.

Estimation of the lactate threshold using bioelectrical impedance spectroscopy: a new noninvasive method.

Bioelectrical Impedance Spectroscopy (BIS) is a noninvasive technology with potential application to study exercise physiology as body composition and estimation of maximal oxygen uptake. The aim of the study was to compare the power at lactate threshold (WLT) obtained using blood lactate concentration (BLC) with the power at lactate threshold from BIS (WBT). Fifty physical education students, 35 men and 15 women (age: 24.1 +/- 5.5 years; height: 168.6 +/- 24.6 cm; weight: 70.1 +/- 9.8 kg), undergoing incremental cycle ergometer test (ICET) have participated of the study. Significant correlations (p<0.05) for Pearson coefficient were found between the two methods (r = 0.96) and standard error of estimate (SEE)=5.6 W. The mean value showed 66.7+/- 20.3 W and 66.7+/- 21.1 W between the invasive technique (WLT) and noninvasive technique (WBT), respectively. The results of this study suggest that BIS, when applied with the ICET, is a valid method to estimate the power at LT.

Electrical impedance model for evaluation of skin irritation in rabbits and humans.

BACKGROUND/AIM: The electrical impedance method has been used as a quantitative technique for evaluating changes in the skin during irritation within the invisible range. The purpose of this study was to apply an electrical model of skin to the interpretation of impedance data after the application of an irritant (SLS) in the skin of humans and rabbits. METHODS: Investigations were performed on 12 humans and 15 albino rabbits. Responses were evaluated by measuring electrical impedance before irritant exposure and 24 h after its removal and also by visual inspection. Using the raw impedance parameter, a novel index was developed and its value was correlated with visual scoring. RESULTS: The derived impedance index showed a significant correlation with visual scores and its value decreased (P<0.05) after irritant removal even without macroscopic signs of irritation. CONCLUSION: The proposed electrical model of skin seems to be suitable for the detection and interpretation of changes in the impedance characteristics of skin induced by SLS in rabbits and humans.

Assessment of acute skin irritation in rabbits using electrical impedance model.

This paper describes the use of an electrical impedance model to assess acute skin reactions to irritant over time. The applied method is noninvasive and quantitative and can detect the irritation before the visual signs. The results showed that the signs of acute irritation (oedema) were present until the second day after irritant application. The method is able to detect the initial phase of irritation and the assessment of regeneration time could be attained by a combination of more than one bioengineering methods.

Simplified distributed-parameter model of brachial-radial arteries for noninvasive determination of mechanical characteristics of vessel.

This paper proposes a simplified distributed-parameter model of the brachial-radial arteries segment for the determination of mechanical parameters of these arteries and compares it with a four-element Windkessel model. The comparison is performed using data collected noninvasively of pressure pulse waveforms at two different locations of the arterial segment, under physiological (normotensive) and pathological (primary hypertension) conditions. The results show, by Akaike Information Criterion, that the proposed model fits the real pressure pulse waveform better than classical Windkessel model, and that also gives mechanical parameters coherent with the clinical condition.

Bioelectrical impedance spectroscopy for the assessment of body fluid volumes of term neonates.

The assessment of fluid volume in neonates by a noninvasive, inexpensive, and fast method can contribute significantly to increase the quality of neonatal care. The objective of the present study was to calibrate an acquisition system and software to estimate the bioelectrical impedance parameters obtained by a method of bioelectrical impedance spectroscopy based on step response and to develop specific equations for the neonatal population to determine body fluid compartments. Bioelectric impedance measurements were performed by a laboratory homemade instrument. The volumes were estimated in a clinical study on 30 full-term neonates at four different times during the first month of life. During the first 24 hours of life the total body water, extracellular water and intracellular water were 2.09 +/- 0.25, 1.20 +/- 0.19, and 0.90 +/- 0.25 liters, respectively. By the 48th hour they were 1.87 +/- 0.27, 1.08 +/- 0.17, and 0.79 +/- 0.21 liters, respectively. On the 10th day they were 2.02 +/- 0.25, 1.29 +/- 0.21, and 0.72 +/- 0.14 liters, respectively, and after 1 month they were 2.34 +/- 0.27, 1.62 +/- 0.20, and 0.72 +/- 0.13 liters, respectively. The behavior of the estimated volume was correlated with neonatal body weight changes, leading to a better interpretation of such changes. In conclusion, this study indicates the feasibility of bioelectrical impedance spectroscopy as a method to help fluid administration in intensive care neonatal units, and also contribute to the development of new equations to estimate neonatal body fluid contents.