Heart rate variability, exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate cystic fibrosis.

Background: Autonomic nervous system balance is altered in cystic fibrosis (CF), although its influence on physical fitness has been poorly explored. Objective: This study aimed to evaluate the association of heart rate variability (HRV) with exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate CF. Methods: A cross-sectional study including individuals with CF aged 6-18 years, not under CFTR modulator therapy, was performed. Sociodemographic (age, sex) and clinical information (airway colonization, pancreatic insufficiency, and genotyping) were collected. In addition, exercise capacity (modified shuttle test - MST), lung function (spirometry), body composition (bioimpedance), levels of daily physical activity (5-day accelerometer), and HRV (both at rest and during the MST) were evaluated. Results: 30 individuals (20 females) aged 11 . 2 ± 3 . 7 years, mean FEV 1 62 . 8 ± 27 . 6 %, were included. A sympathovagal balance (LF/HF) increase ( p < 0 . 001 ) during the MST was shown, indicating a predominance of sympathetic modulation. The standard deviation of all RR intervals (SDNN) and the high frequency (HF) index during exercise correlated significantly with FEV1 ( r = 0 . 45 , p = 0 . 01 and r = 0 . 46 , p = 0 . 01 ; respectively). MST distance also correlated positively and significantly with SDNN ( r = 0 . 43 , p = 0 . 01 ), square root of the mean of the sums of squares of frequencies between RR intervals greater than 50 ms - RMSSD ( r = 0 . 53 , p < 0 . 01 ), low frequency - LF ( r = 0 . 48 , p < 0 . 01 ), HF ( r = 0 . 64 , p < 0 . 01 ), dispersion of points perpendicular to the short-term identity line - SD1 ( r = 0 . 40 , p = 0 . 02 ) and negatively with LF/HF ( r =- 0 . 57 , p < 0 . 01 ). Regarding daily physical activity, SDNN at rest ( r = 0 . 37 , p = 0 . 04 ) and exercise ( r = 0 . 41 , p = 0 . 02 ) showed positive correlations with time in moderate-to-vigorous activities. When normalizing the SDNN and classifying individuals as normal or altered, those presenting altered SDNN showed poorest FEV1 ( p = 0 . 001 ) and lower exercise capacity ( p = 0 . 027 ). Conclusion: HRV correlates with lung function, exercise capacity and levels of daily physical activity in children and adolescents with CF. The study highlights the influence of CF on autonomic function and suggests HRV measurement as an easy tool to be used in clinical settings as an alternative marker to monitor CF individuals.

Irreversible deformation of hyper-crosslinked polymers after hydrogen adsorption.

Hyper-crosslinked polymers (HCPs) have been produced by the Friedel-Crafts reaction using anthracene, benzene, carbazole or dibenzothiophene as precursors and dimethoxymethane as crosslinker, and the effect of graphene oxide (GO) addition has been studied. The resulting HCPs were highly microporous with BET areas (ABET) between 590 and 1120 m2g-1. The benzene-derived HCP (B1FeM2) and the corresponding composite with GO (B1FM2-GO) exhibited the highest ABET and were selected to study their hydrogen adsorption capacities in the pressure range of 0.1 - 14 MPa at 77 K. The maximum H2 excess uptake was 2.1 and 2.0 wt% for B1FeM2 and B1FeM2-GO, respectively, at 4 MPa and 77 K. The addition of GO reduced the specific surface area but increased the density of the resultant HCP-GO composites, which is beneficial for practical applications and proves that materials giving higher gravimetric storage capacities are not necessarily those that offer higher volumetric capacities. H2 adsorption-desorption cycles up to 14 MPa showed irreversible deformation of both HCP and HCP-GO materials, which calls into question their application for hydrogen adsorption at pressures above 4 MPa.

Comparison of cardiac autonomic modulation of athletes and non-athletes individuals with spinal cord injury at rest and during a non-immersive virtual reality task.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: To compare cardiac autonomic modulation of individuals with spinal cord injury (SCI) that practice different amounts of moderate to vigorous physical activity (PA) and able-bodied controls at rest and during a non-immersive Virtual Reality task. SETTING: Athletes with SCI of wheelchair basketball, wheelchair tennis, wheelchair handball, WCMX (wheelchair motocross), and para-swimming were assessed at the Faca na Cadeira Institute, ICEL and Clube Espéria in São Paulo, Brazil; non-athletes with SCI and able-bodied controls were assessed at the Acreditando Centro de Recuperação Neuromotora, São Paulo, Brazil. METHODS: One-hundred forty-five individuals were assessed: 36 athletes with traumatic SCI (41.1 ± 16.8 years old), 52 non-athletes with traumatic SCI (40.2 ± 14.1 years old), and 57 able-bodied individuals (39.4 ± 12.5 years old). Cardiac autonomic modulation was assessed through heart rate variability (HRV) measured in the sitting position at rest and during a VR game activity. RESULTS: We found significantly more favourable HRV for athletes with SCI when compared to non-athletes with SCI, but no differences between athletes with SCI and able-bodied controls. In addition, athletes and able-bodied controls showed adequate autonomic nervous system (ANS) adaptation (rest versus physical activity in VR), i.e., they experienced parasympathetic withdrawal during VR physical activity, which was not found in non-athletes with SCI. CONCLUSION: The practice of moderate to vigorous physical activity is associated with healthier cardiac autonomic modulation in adults with SCI, which may lead to more favourable health outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04618003, retrospectively registered.

Association of sleep disorders with heart rate variability in children and adolescents with cystic fibrosis.

OBJECTIVE: To assess the association of sleep disorders with the findings of heart rate variability (HRV) in children and adolescents with cystic fibrosis (CF). METHODS: Cross-sectional study including children and adolescents aged six to 18 years with a clinical diagnosis of CF. Sociodemographic and clinical data were collected. Sleep disorders were evaluated using baseline nocturnal polysomnography. The autonomic nervous system (ANS) was evaluated through resting HRV. RESULTS: A total of 30 individuals (11.2 years) with a mean forced expiratory volume in the first second (FEV1) of 62.7% were included. The respiratory disturbance index presented a median of 2.6 and obstructive sleep apnea syndrome (OSAS) was identified in 30%. In the HRV analysis, a mean standard deviation of all inter-beat (RR) intervals (SDNN) of 60.8±45.9ms was found. There was a significant correlation between the HRV low-frequency/high-frequency (LF/HF) global modulation index and the minimum SpO2 during sleep in patients with FEV1<60% (r=0.71; p=0.02). The prevalence of sleep disorders and HRV abnormalities was higher in individuals with lesser pulmonary function (FEV1<60%). CONCLUSIONS: The results indicate a weak correlation of sleep disorders (minimum SpO2) with HRV parameters (LH/HF) in children and adolescents with CF. When pulmonary function was reduced, a stronger correlation was found, highlighting the influence of disease severity. A high prevalence of ANS disorders, nocturnal hypoxemia, and presence of OSAS was also found.

Capacidade de exercício e nível de atividade física diária de crianças e adolescentes com fibrose cística: associação com estado nutricional, função pulmonar, hospitalização e uso de antibióticos / Capacidad de ejercicio y nivel de actividad física diaria de niños y adolescentes con fibrosis quística: asociación con estado nutricional, función pulmonar, hospitalización y uso de antibióticos / Exercise capacity and daily physical activity levels in children and adolescents with cystic fibrosis: association with nutritional status, lung function, hospitalization and antibiotic use

RESUMO O objetivo deste trabalho é avaliar a capacidade de exercício e nível de atividade física diária de crianças e adolescentes com fibrose cística e associar com estado nutricional, função pulmonar, tempo de hospitalização e uso de antibióticos. Trata-se de estudo transversal em indivíduos com fibrose cística entre 6 e 18 anos, registrando-se informações sobre perfil clínico, histórico de hospitalizações e uso de antibióticos. Os participantes foram submetidos à espirometria, bioimpedância, avaliação da capacidade de exercício com teste de Shuttle modificado (MST), o nível da atividade física foi medido por meio do questionário internacional de atividade física (IPAQ) e usando acelerômetro por 5 dias. Participaram 30 indivíduos com idade de 11,2 ± 3,6 anos e volume expirado forçado (VEF1) de 68,0 ± 24,8%. A mediana da distância percorrida no MST foi de 820 metros (66,3%) e demonstrou associação com a função pulmonar (r = 0,78), estado nutricional (r = 0,38), tempo de hospitalização (r = -0,42) e uso de antibióticos (r = -0,46). De acordo com o questionário, 20 pacientes (64,6%) foram classificados como sedentários, o acelerômetro revelou que os indivíduos passam 354,2 minutos em atividades sedentárias e apenas 14,9 minutos em atividades moderadas a vigorosas por dia. Quanto maior a porcentagem de tempo em atividade física moderada a vigorosa, maior o índice de massa corpórea (IMC) e menor o tempo de hospitalização. Assim, a capacidade de exercício e nível de atividade física em crianças e adolescentes com fibrose cística apresentou-se reduzida e associada com menores valores de IMC e aumento do tempo de hospitalização.

RESUMEN El propósito de este trabajo fue evaluar la capacidad de ejercicio y el nivel de actividad física diaria de los niños y adolescentes con fibrosis quística, así como asociarlos con el estado nutricional, la función pulmonar, la duración de la permanencia hospitalaria y el uso de antibióticos. Este es un estudio transversal realizado con individuos con fibrosis quística con edades comprendidas entre los 6 y los 18 años, y que registra información sobre el perfil clínico, los antecedentes de hospitalizaciones y el uso de antibióticos. Los participantes se sometieron a la espirometría, la bioimpedancia, la evaluación de la capacidad de ejercicio con la prueba de Shuttle modificada (MST); para medir el nivel de actividad física se aplicó el Cuestionario Internacional de Actividad Física (IPAQ) y el uso del acelerómetro durante 5 días. Participaron 30 personas de entre 11,2 ± 3,6 años de edad y volumen espirado forzado (VEF1) de 68,0 ± 24,8%. La mediana de la distancia recorrida en el MST fue de 820 metros (66,3%) y se mostró asociación con la función pulmonar (r=0,78), el estado nutricional (r=0,38), la duración de la permanencia hospitalaria (r=-0,42) y el uso de antibióticos (r=-0,46). El cuestionario reveló que 20 pacientes (64,6%) estaban sedentarios, y el acelerómetro evidenció que ellos pasan 354,2 minutos en actividades sedentarias y solo 14,9 minutos en actividades moderadas a intensas al día. Cuanto mayor sea el porcentaje de tiempo dedicado a la actividad física moderada a intensa, mayor será el índice de masa corporal (IMC) y menor la duración de la permanencia hospitalaria. Por lo tanto, la capacidad de ejercicio y el nivel de actividad física de niños y adolescentes con fibrosis quística fueron menores y están asociadas con bajos valores de IMC y con una permanencia hospitalaria más prolongada.

ABSTRACT To evaluate the exercise capacity and daily physical activity level among children and adolescents with cystic fibrosis, and its association with nutritional status, lung function, hospitalization time, and days taking antibiotics. This is a cross-sectional study in individuals with cystic fibrosis aged 6 to 18 years. Information on clinical profile, history of hospitalizations and antibiotic use were collected. Participants were submitted to spirometry, bioimpedance, and an assessment of exercise capacity with modified shuttle test (MST), and the level of physical activity was measured with the International Physical Activity Questionnaire (IPAQ) using an accelerometer for 5 days. In total, 30 individuals participated, aged 11.2±3.6 years, and 68.0±24.8% in forced expired volume in the first second (FEV1). The median distance covered in the MST was 820 meters (66.3%), showing association with lung function (r=0.78), nutritional status (r=0.38), hospitalization time (r=-0.42) and antibiotic use (r=-0.46). According to the questionnaire, 20 patients (64.6%) were classified as sedentary, the accelerometer revealed that the individuals spend 354.2 minutes in sedentary activities and only 14.9 minutes in moderate to vigorous activities per day. The higher the percentage of time in moderate to vigorous physical activity, the higher the body mass index (BMI) and the shorter the hospitalization time. Exercise capacity and level of physical activity in children and adolescents with cystic fibrosis is reduced and associated with lower BMI values and with an increase in hospitalization time.

A Step Forward in Understanding the Hydrogen Adsorption and Compression on Activated Carbons.

Hydrogen adsorption on activated carbons (ACs) is a promising alternative to compression and liquefaction for storing hydrogen. Herein, we have studied hydrogen adsorption on six commercial ACs (CACs) with surface areas ranging from 996 to 2216 m2 g-1 in a temperature range of 77 to 273 K and pressures up to 15 MPa. Excess hydrogen adsorption capacities of 2.3 to 5.8 wt % were obtained at 77 K and 4 MPa. We demonstrated that, contrary to what is normally done, hydrogen capacity is more accurately predicted by the surface area determined by the nonlocal density functional theory method applied to N2 and CO2 adsorption data than by the Brunauer-Emmett-Teller (BET) area. The modified Dubinin-Astakhov (MDA) equation was used to fit the experimental adsorption data, and the relationship between the MDA parameters (nmax, Va, α, and ß) and the textural properties of the CACs was determined for the first time. We concluded that the nmax and Va parameters are related to the BET area, while the α and ß parameters are related to the average micropore size and total pore volume, respectively. α and ß were used to evaluate the enthalpy and entropy of adsorption and we show that these parameters can be used to assess the best carbon for hydrogen storage or compression.

Sleep disorders are distinctively associated with exercise intolerance and sedentary behavior in children with cystic fibrosis.

OBJECTIVE: To evaluate the presence of sleep disorders and its associations with exercise capacity and daily physical activity levels among children and adolescents with CF. METHODS: Children age 6-18 years with a diagnosis of CF were recruited. Information regarding sociodemographic profile, pulmonary function and nutritional status were collected. Sleep disorders (polysomnography), exercise capacity (modified shuttle test - MST) and daily physical activity levels (questionnaire and five days accelerometer use) were evaluated. RESULTS: Thirty-one patients, median age of 9.6 years and forced expiratory volume in 1 s (FEV1) of 68.1 ± 24.4%, were included. Obstructive sleep apnea syndrome (OSAS) was present in 32.3% and nocturnal hypoxemia in 29%. The MST distance correlated with the mean peripheral oxyhemoglobin saturation (SpO2) during sleep (r = 0.40) and the percent of total sleep time with SpO2<90% (r = -0.49). The final MST SpO2 correlated with the occurrence of OSAS (r = -0.48) and mean nocturnal SpO2 (r = 0.45). Sedentary activities, as measured by accelerometry, correlated with sleep architecture, including the percent of stage II (r = 0.60) and rapid eye movement (REM) stage sleep (r = -0.37). Patients with OSAS and nocturnal hypoxemia presented lower values (p < 0.05) of distance and final SpO2 in the MST. Nocturnal hypoxemia was the main variable to influence exercise capacity (r2 = 0.521). CONCLUSION: Sleep disorders are distinctively related with exercise capacity and daily physical activity levels, as nocturnal hypoxemia is associated with exercise intolerance and sleep architecture disorders are associated with sedentary physical activity levels.

Sleep-disordered breathing and markers of morbidity in children and adolescents with cystic fibrosis.

BACKGROUND: Studies have shown that sleep disorders occur in cystic fibrosis (CF) patients and may be present before daytime clinical manifestations. OBJECTIVES: To evaluate the presence of sleep disorders among children and adolescents with CF, attempting to identify associations with pulmonary function, nutritional status, days in hospital, and days taking antibiotics. METHODS: Individuals with a diagnosis of CF aged between 6 and 18 years were included. Information on sociodemographic, clinical profile, history of hospitalizations, and use of antibiotics in the last year were collected. Spirometry, bioimpedance, and polysomnography were performed. The presence of nocturnal hypoxemia and obstructive sleep apnea syndrome (OSAS) were evaluated and participants divided according to their presence. RESULTS: Thirty-one patients were included. The prevalence of OSAS was 32.3% and nocturnal hypoxemia was 29.0%. Average nocturnal peripheral oxyhemoglobin saturation (SpO2 ) correlated (P < .001) with forced vital capacity (r = .55) and forced expiratory volume in the first second (r = .62). The higher the percentage of total sleep time (TST) with SpO2 less than 90%, the lower the pulmonary function. Individuals with OSAS and nocturnal hypoxemia had lower spirometric values compared to patients without these disorders, but the nocturnal hypoxemia group also had lower Shwachman-Kulczycki score, longer hospitalization time and antibiotic use. TST with SpO2 less than 90% was associated with length of hospitalization (r2 = .53). CONCLUSION: Children and adolescents with CF have sleep disorders, including OSAS (32.3%) and nocturnal hypoxemia (29%). Individuals with nocturnal hypoxemia presented lower lung function, worse clinical score, and higher morbidity. TST with SpO2 less than 90% was associated with length of hospitalization.

[Brucellosis in Chile: Description of a series of 13 cases]. / Brucelosis en Chile: Descripción de una serie de 13 casos.

INTRODUCTION: Brucellosis is a zoonosis caused by Brucella spp. It may be acquired by consuming unpasteurized dairy products. Brucellosis has a low incidence in Chile, thus, we have a scarce data. AIM: To report and to characterize the first series of clinical cases of adult patients diagnosed with brucellosis in Chile. METHODS: We describe a series of 13 clinical cases in patients diagnosed between 2000 and 2016 in three different centers in the Metropolitan Region, Chile. A retrospective analysis was performed on clinical presentation, laboratory, antibiotic treatment, morbidity and mortality. RESULTS: The mean age was 50 years old. Eight cases had a record of consumption of unpasteurized dairy products. The most frequently reported complaints were fever. The most frequent focal point involved was the spine. Only one patient had a positive blood culture, while the diagnosis was made using serological techniques in the other part of the group. The most indicated antibiotic regimens were doxycycline-rifampicin and doxycycline-gentamicin. The hospital stay was 20 days approximately as an average. Clinical cure was achieved in all cases. CONCLUSIONS: Brucellosis is an infrequent zoonosis in Chile, and it produces a nonspecific clinical picture, so it is necessary to have high suspicion to make the diagnosis based in the antecedent of consumption of unpasteurized dairy or raw meat.

[Pertussis vaccination in pregnancy: Security and effectiveness in the protection of the infant]. / Vacunación con pertussis en el embarazo: una estrategia segura y efectiva para proteger al lactante menor.

Whooping cough is an immune preventable disease that can be life threatening. Despite infant immunization starting at 2 month of age, there are many cases and outbreaks in our country and also around the world, with a high risk of mortality specially in infants under 6 month of age. It has been proposed that antenatal vaccination with acellular pertussis component (Tdap) would be useful, safe and effective since it transfers a high antibody rate to the child, reducing the incidence of pertussis in this group by 85%. No higher incidence of adverse effects has been found in pregnant women with this vaccine. This strategy has been implemented in several developed and Latin American countries. The purpose of this manuscript is to review and discuss the benefits of antenatal vaccination with Tdap. It was concluded that maternal immunization with Tdap vaccine should be promoted to prevent infection and associated mortality in the less than 6 months of age by Bordetella pertussis.

Brucelosis en Chile: descripción de una serie de 13 casos / Brucellosis in Chile: description of a series of 13 cases

Introduction: Brucellosis is a zoonosis caused by Brucella spp. It may be acquired by consuming unpasteurized dairy products. Brucellosis has a low incidence in Chile, thus, we have a scarce data. Aim: To report and to characterize the first series of clinical cases of adult patients diagnosed with brucellosis in Chile. Methods: We describe a series of 13 clinical cases in patients diagnosed between 2000 and 2016 in three different centers in the Metropolitan Region, Chile. A retrospective analysis was performed on clinical presentation, laboratory, antibiotic treatment, morbidity and mortality. Results: The mean age was 50 years old. Eight cases had a record of consumption of unpasteurized dairy products. The most frequently reported complaints were fever. The most frequent focal point involved was the spine. Only one patient had a positive blood culture, while the diagnosis was made using serological techniques in the other part of the group. The most indicated antibiotic regimens were doxycycline-rifampicin and doxycycline-gentamicin. The hospital stay was 20 days approximately as an average. Clinical cure was achieved in all cases. Conclusions: Brucellosis is an infrequent zoonosis in Chile, and it produces a nonspecific clinical picture, so it is necessary to have high suspicion to make the diagnosis based in the antecedent of consumption of unpasteurized dairy or raw meat.

Introducción: La brucelosis es una zoonosis provocada por Brucella spp, cuyo principal mecanismo de transmisión es mediante el consumo de lácteos no pasteurizados. Es de baja ocurrencia en Chile, por lo que los datos locales son escasos. Objetivo: Reportar y caracterizar la primera serie de casos clínicos de pacientes adultos con diagnóstico de brucelosis en Chile. Material y Método: Se describe una serie de 13 casos clínicos en pacientes diagnosticados entre el año 2000 y el 2016 en tres centros de la Región Metropolitana, Chile. Se realizó un análisis retrospectivo acerca de la presentación clínica, laboratorio, tratamiento antimicrobiano y morbi-mortalidad. Resultados: El promedio de edad fue 50 años. Ocho casos tenían antecedente de consumo de lácteos no pasteurizados. El motivo de consulta más frecuente fue sensación febril. El compromiso focal más frecuente fue el de columna vertebral. Sólo en un paciente se encontró hemocultivo positivo; en el resto el diagnóstico se hizo mediante técnicas serológicas. Los esquemas antimicrobianos más indicados fueron doxiciclina-rifampicina y doxiciclina-gentamicina. La estadía hospitalaria fue en promedio de 20 días. En todos los casos se logró curación clínica. Conclusiones: La brucelosis es una zoonosis infrecuente en Chile, produce un cuadro clínico inespecífico, por lo que se debe tener una alta sospecha para realizar el diagnóstico, basada en el antecedente del consumo de productos lácteos no pasteurizados o de carne mal cocida.

Vacunación con pertussis en el embarazo: una estrategia segura y efectiva para proteger al lactante menor / Pertussis vaccination in pregnancy: Security and effectiveness in the protection of the infant

El coqueluche es una enfermedad inmunoprevenible que puede amenazar la vida. A pesar de la vacunación en lactantes desde los 2 meses de edad, se siguen presentando casos y brotes a nivel nacional y mundial, con un alto riesgo de morbimortalidad en los menores de 6 meses. Se ha planteado que la vacunación antenatal con componente pertussis acelular (Tdpa) sería útil, segura y efectiva, dado que transfiere una alta tasa de anticuerpos al niño, disminuyendo en 85% la incidencia de coqueluche en este grupo. No se ha encontrado mayor incidencia de efectos adversos en embarazadas con esta vacuna. Esta estrategia ha sido implementada en varios países desarrollados y de Latinoamérica. El objetivo del presente manuscrito es revisar y discutir los beneficios de la vacunación antenatal con Tdpa. Se concluye que se debiera promover la inmunización materna con vacuna Tdpa para prevenir la infección y mortalidad asociada en el menor de 6 meses de vida por Bordetella pertussis.

Whooping cough is an immune preventable disease that can be life threatening. Despite infant immunization starting at 2 month of age, there are many cases and outbreaks in our country and also around the world, with a high risk of mortality specially in infants under 6 month of age. It has been proposed that antenatal vaccination with acellular pertussis component (Tdap) would be useful, safe and effective since it transfers a high antibody rate to the child, reducing the incidence of pertussis in this group by 85%. No higher incidence of adverse effects has been found in pregnant women with this vaccine. This strategy has been implemented in several developed and Latin American countries. The purpose of this manuscript is to review and discuss the benefits of antenatal vaccination with Tdap. It was concluded that maternal immunization with Tdap vaccine should be promoted to prevent infection and associated mortality in the less than 6 months of age by Bordetella pertussis.

[Plasmapheresis in neurological diseases. Experience in 140 procedures in 47 patients]. / Plasmaféresis indicada por enfermedad neurológica. Experiencia de 140 procedimientos en 47 pacientes.

BACKGROUND: Plasmapheresis can be useful in myasthenia gravis, Guillain Barré syndrome and chronic demyelinating inflammatory polyradiculoneuritis. AIM: To report our experience with plasmapheresis in patients with neurological diseases. MATERIAL AND METHODS: Retrospective review of plasmapheresis procedures done between 1995 and 2001, in a public hospital. Indications criteria, clinical results and technical yield were analyzed. RESULTS: One hundred fifty nine procedures were reviewed. One hundred forty (88%) were indicated for neurological diseases (44% for Guillain Barré syndrome and 29% for myasthenia gravis). Clinical improvement or eventual complications were avoided in 70% of patients with Guillain Barré syndrome and 100% of patients with myasthenia gravis. Hypotension in 10% and paresthesias in 7% were observed. All complications were successfully controlled with crystalloid or fresh plasma infusions or citrate management. In 11 cases, the procedure was interrupted due to obstruction of the venous access, that was peripheral in eight of these. The most common difficulties of the procedure were delay in performing it in 50% of patients and insufficient exchange volumes in 30%. CONCLUSIONS: Plasmapheresis was safe and useful in patients with myasthenia gravis and Guillain Barré syndrome. The drawbacks of the procedure are its costs and requirement of special equipment.