Abstract In order to describe the effects of origin (Mexico and United States of America), sex, age at slaughter (AS, 4 categories), body condition score (BCS, 5 categories) and slaughter weight (SW, 4 categories) on carcass characteristics of culled quarter horses, data from 235 horses sacrificed in the same slaughter facility within a 150 days period were analyzed. Overall, 74.5% were from the US, 80% were < 15 years of age and had BCS ≤ 4, and sex proportion was similar (51.5% female vs 48.5% males). Horses from USA had heavier SW (27%), leg circumference (4%), carcass weight (4.2%) and carcass yield (2.9%). Sex did not affect any characteristics evaluated. Horses from 3 to 8 years had greater rib eye area (REA) and backfat thickness. Except for leg length, as BCS and SW improved, all carcass characteristics linearly increased as BCS and SW increased. It is concluded that origin, sex, and age, explained very little on the carcass characteristics. The slaughter weight mainly explained changes in linear measures, carcass weight, and compact index, while BCS mainly explained carcass yield and REA.

Resumen Para describir los efectos de origen (México y Estados Unidos de América), sexo, edad al sacrificio (AS, 4 categorías), puntaje de condición corporal (BCS, 5 categorías) y peso de faena (SW, 4 categorías) se utilizaron datos de 235 caballos cuartos de milla sacrificados en una misma instalación durante un período de 150 días. Del total, el 74.5 % provenían de EUA, el 80 % fue <15 años y una BCS ≤ 4, la proporción de sexos fue similar (51.5 % hembras vs 48.5 % machos). Los caballos EUA presentaron mayor SW (27 %), circunferencia de pierna (4 %), peso en canal (4.2 %) y rendimiento en canal (2.9 %). El sexo no afectó ninguna característica evaluada. Los caballos de 3 a 8 años presentaron mayor área del ojo de la costilla (REA) y grasa dorsal. Exceptuando la longitud de pierna, las características de la canal aumentaron linealmente a medida que aumentaron BCS y SW. Se concluye que origen, sexo y edad explican poco sobre las características de la canal. El peso al sacrifico explicó principalmente los cambios en las medidas lineales, peso de la canal e índice compacto, mientras que BCS explicó principalmente el rendimiento de la canal y REA.

Introduction: Obstructive sleep apnea (OSA) is more prevalent in men, population studies show a ratio of 2:1, however in clinical studies the frequency is as high as 6:1. These differences in the clinical setting may be a consequence of variations in the reporting of symptoms in men compared to women. Objective: To evaluate gender differences between women and men with recent diagnosis of OSA. Patients: A cross-sectional, study of patients undergoing home sleep apnea testing (HSAT) with clinical suspicion of OSA. Demographic, anthropometric, comorbidities and HSAT variables were collected. We performed t student analysis, Mann-Whitney test or chi square test as appropriate. Results: 1,044 patients were included: mean age 53.2 ± 14 years, 76% men. Women with OSA have a higher BMI (32.2 ± 6.1 vs 30.8 ± 5.0, p = 0.002), were older (61.4 ± 12.2 vs 52.6 ± 13.9, p <0.001), but have a lower neck circumference (NC) (38.1 ± 3.6 vs. 43.2 ± 3.3, p <0.001). The women presented lower AHI and shorter duration of apneas. Although the classic symptoms of apnea and daytime sleepiness showed no differences, women reported more frequently insomnia, morning headache, depression and use of hypnotic drugs. Conclusions: Clinical differences between gender are present at time of diagnosis. Woman are older and more obese, although they have a lower NC. They have a milder disease, but they refer to be more tired, headache, insomnia and depression. We must be alert in the different clinical presentation of women to improve the diagnostic suspicion.

Resumen Introducción: El síndrome de apnea obstructiva del sueño (SAHOS) es más prevalente en hombres, los estudios poblacionales muestran una relación de 2:1, sin embargo, en los estudios clínicos la frecuencia llega a ser de hasta de 6:1. Estas diferencias en el ambiente clínico puede ser consecuencia de variaciones en el reporte de síntomas en hombres comparados con mujeres. Objetivo: Evaluar las diferencias de género en la presentación clínica de apnea obstructiva de sueño. Pacientes: Estudio transversal de pacientes sometidos a una poligrafía respiratoria (PR) con sospecha clínica de SAHOS. Se recolectaron datos demográficos, antropométricos, comorbilidades y las variables de la PR. Se realizó estudio t de student, Mann-Whitney y chi-cuadrado según correspondiera. Resultados: Se incluyeron 1.044 pacientes: edad promedio 53,2 ± 14 años, 76% hombres. Las mujeres con SAHOS poseen mayor IMC (32,2 ± 6,1 vs 30,8 ± 5,0; p=0,002) y edad (61,4 ± 12,2 vs 52,6 ± 13,9; p < 0,001), pero menor circunferencia de cuello (CC) (38,1 ± 3,6 vs 43,2 ± 3,3; p < 0,001), además, presentan menor IA/H y menor duración de las apneas. No hubo diferencias en los síntomas clásicos de apneas presenciada y somnolencia diurna, sin embargo, describen más frecuentemente insomnio, cefalea matinal, depresión y uso de fármacos hipnóticos. Conclusiones: Las mujeres al momento del diagnóstico son de mayor edad y más obesas, aunque presentan una CC menor, presentan una enfermedad más leve, pero refieren más fatiga, cansancio, cefalea e insomnio. Debemos estar alerta en la presentación clínica diferente de las mujeres para mejorar la sospecha diagnóstica.

Introduction: Obstructive sleep apnea syndrome (OSA) is the result of repetitive collapse of the upper airway during the sleep. There is a group of patients with a positional component; which is defined as a reduction of at least 50% in the apnea hypopnea index (AHI) from the supine to a lateral position. Objective: The purpose of this study is to determine positional OSA prevalence and compare clinical characteristics and polygraph recordings among this group of patients. Methods: Prospective study of polygraph recording of patients with suspect of OSA between 2009-2014. Demographic, anthropometric, comorbidities and polygraph recording data was collected. OSA was defined as AHI > 5 events per hour Results: From a total of 457 patients with OSA diagnose, 243 had a positional component (53%). Positional Sleep Apnea patients had mild AHI (p < 0.001), a lower neck circumference (p = 0.001), lower Body Mass Index (p = 0.003) and a lower presence of arterial hypertension (p = 0.001). The multivariable analysis confirmed that there is a lower probability in Positional OSA in patients with Severe AHI (OR 0,96: IC 0,94-0,97), with hypertension (0,54: IC 0,33-0,88) and males (OR 0,41: IC 0,21-0,81). Conclusions: Positional obstructive sleep apnea is a very frequent condition presented in 53% of OSA patients; these patients have often mild AHI, lower BMI, lower neck circumference, less hypertensive, and are usually females.

Introducción: El síndrome de apnea e hipopnea obstructiva del sueño (SAHOS) es producto de un colapso repetido a nivel de la vía aérea superior, durante el sueño. Existe un grupo de pacientes con SAHOS con componente postural, definida por una reducción del 50% o más en el índice de apnea hipopnea (IAH) de la posición supina a la lateral. Objetivo: Determinar la prevalencia de SAHOS postural y comparar las características clínicas y de la poligrafía respiratoria (PR) de este grupo de pacientes. Metodología: Estudio prospectivo de PR entre 2009-2014, derivados a realización de estudio por sospecha clínica de SAHOS. Se recolectaron datos demográficos, antropométricos, comorbilidades y diferentes variables de la PR. Se definió presencia de SAHOS un IAH mayor de 5 eventos/h. Resultados: De un total de 457pacientes con diagnóstico de SAHOS, 243presentaban SAHOS postural (53%). Los pacientes con SAHOS postural eran más leves (p < 0,001), tenían una circunferencia cervical (p = 0,001) e índice de masa corporal (p = 0,003) menor y con menor frecuencia eran hipertensos (p = 0,001). El análisis multivariado confirmó menor probabilidad SAHOS postural en sujetos con IAH graves (OR 0,96: IC 0,94-0,97): hipertensos (0,54: IC 0,33-0,88) y de sexo masculino (OR 0,41: IC 0,21-0,81). Conclusiones: El SAHOS postural es una entidad muy frecuente que está presente en el 53% de los pacientes con SAHOS, estos sujetos tienden a presentar enfermedad más leve, tener un IMC y circunferencia cervical menor, menor frecuencia de hipertensión arterial y son preferentemente mujeres.

Twelve Pelibuey ewes were used to evaluate the effect of replacing soybean meal (PS) with a handmade product made of fish (HP) on milk yield and composition and body weight of their suckling lambs. The experimental period was carried out during the first three weeks of lactation, where changes in body weight, feed intake and milk production and composition were evaluated in sheep, and changes in body weight were evaluated on 22 of their lambs (initial wt = 2.52 ± 0.05 kg). The control diet and test diet were formulated to meet nutrient requirements of ewes during early lactation. The level of inclusion of PS and HP in diets was 7 and 3.5%, respectively. HP was elaborated with fish by-products (whole fish, heads, tails, and backbone). The chemical composition of HP averaged 50.8 ± 7.7% CP, fat 9.4 ± 0.8% and 22.7 ± 5.9% ash. There were no differences in BW changes and milk production. The protein content in milk and final body weight of suckling lambs were greater (P < 0.01) in the case of HP when compared to PS. It was concluded that HP is a suitable substitute of PS in lactating ewes and it does not affect DM intake and milk performance. An increase of protein concentration in milk from ewes that received HP may result in a greater body weight of the lambs during the first 21 days of age.

Se utilizaron 12 borregas raza Pelibuey para evaluar el efecto de la sustitución de la pasta de soya (PS) con una harina de pescado obtenida artesanalmente (HP) sobre producción y composición de la leche y el peso de sus corderos lactantes. La evaluación se realizó en las primeras tres semanas de lactación, donde se evaluaron los cambios de peso corporal, consumo de alimento, producción y composición de leche, así como los cambios de peso corporal de sus corderos lactantes. La dieta testigo (PS) y la dieta prueba (HP) fueron formuladas para cubrir los requerimientos de borregas en lactación temprana. La HP fue elaborada con subproducto de pescado (pescados enteros, cabezas, colas y columnas vertebrales). La composición química promedio del HP fue de: 50,8 ± 7,7% de PC; 9,4 ± 0,8% de grasa y 22,7 ± 5,9% de ceniza. No hubo diferencias en el peso corporal y producción de leche de las borregas. El contenido de proteína en leche y peso de los corderos de las borregas alimentadas con HP fue mayor (P < 0,01) comparadas con las del grupo PS. Se concluyó que es posible sustituir la pasta de soya con harina de pescado artesanal sin alterar el comportamiento productivo en borregas en lactación. Incrementos en la concentración de proteína en leche con HP puede ser reflejado en el peso de los corderos lactantes durante sus primeros 21 días de vida.

The production of lactic urea and the factors that affect it were evaluated. A weekly sample of milk was collected and the daily production of 20 fully lactating cows was recorded. A completely random design with a multiple factorial array was used. The response variable was the content of lactic urea, and the factors were the production levels and the milk protein. The mean amount of lactic urea in the milk was 12.46 mg dl-1. There were no differences (p ≥ 0.05) among the production systems. The content of lactic urea related to a < 5kg (11.48 mg dl-1)b production level was significantly different (p ≤ 0.05) from the ≥ 5 production level, but the ≤ 10 kg (12.8 mg dl-1)ª and > 10 kg (13.07 mg dl-1)ª levels were statistically equal (p ≥ 0.05). The contents of lactic urea found in the < 3.0% (13.2 mg dl-1)ª level of milk protein were different (p ≤ 0.05) from the concentration of urea found in the > 3.2% (11.97 mg dl-1)b level of milk protein. There were no significant differences (p ≥ 0.05) in the interactions between production and milk protein. The concentration of lactic urea in August (8.77 mg dl-1)d was statistically different (p ≤ 0.05) from that of february (12.48 mg dl-1)abc, june (13.57 mg dl-1)abc, July (14.05 mg dl-1)ª, september (13.47 mg dl-1)abc, october (13.62 mg dl-1)ab, november (13.83 mg dl-1)ª and december (14.29 mg dl-1)ª. It is concluded that the levels of lactic urea found in the herd are adequate, and that these levels are affected by the production levels and the protein contained in the milk.

Se evaluó la producción de urea láctea y los factores que la afectan. Se realizó un muestreo de leche semanalmente y se registró la producción diaria de 20 animales de lactancia completa. Se utilizó un Diseño Completamente al Azar con arreglo factorial múltiple. La variable de respuesta fue el contenido de urea láctea, tomando como factores el sistema de producción, niveles de producción y proteína en leche. La media de urea en leche fue 12.46 mg dl-1. No existieron diferencias (p ≥ 0.05) entre los sistemas de producción. El contenido de urea láctea correspondiente al nivel de producción < 5kg (11.48 mg dl-1)b presento diferencia significativa (p ≤ 0.05) con los niveles de producción ≥ 5 pero ≤ 10 kg (12.8 mg dl-1)ª y > 10 kg (13.07 mg dl-1)ª no existieron diferencias (p ≥ 0.05). Los contenidos de urea láctea encontrados en el nivel < 3.0% (13.2 mg dl-1)ª de proteína en leche presentaron diferencias (p ≤0.05) con la concentración de urea encontrado para el nivel > 3.2% (11.97 mg dl-1)b de proteína en leche. No existieron diferencias significativas (p ≥ 0.05) en las interacciones producción y proteínas en leche. La concentración de urea láctea en agosto (8.77 mg dl-1)d fue diferente estadísticamente (p ≤ 0.05) de las concentraciones de febrero (12.48 mg dl-1)abc, junio (13.57 mg dl-1)abc, julio (14.05 mg dl-1)ª, septiembre (13.47 mg dl-1)abc, octubre (13.62 mg dl-1)ab, noviembre (13.83 mg dl-1)ª y diciembre (14.29 mg dl-1)ª. Se concluye que los niveles de urea láctea encontrados en el hato son adecuados y que estos niveles son afectados por los niveles de producción y proteína contenida en leche.

Background: Obstructive sleep apnea syndrome (OSA) is an important cause of morbidity and mortality in adults. Aim: To evaluate the diagnostic value of clinical features and oximetric data to screen for obstructive sleep apnea before performing polysomnograpy or respiratory polygraphy. Material and Methods: We studied 328 consecutive adult patients referred for snoring or excessive daytime sleepiness to a sleep clinic in whom a standardized questionnaire and the Sleepiness Epworth Scale were performed and body mass index (BMI), cervical circumference (CC), and nocturnal oximetry were measured. Results: Fifty three percent (n = 173) had evidence of clinically significant OSA (apnea/hypopnea index (AHI) > 15 events/h). Patients with OSA were more likely to be male, obese (BMI ≥ 26 kg/m²), smokers, to have a thick neck (CC > 41 cm), and to have a significant greater prevalence of relative reported apneas and excessive daytime sleepiness, as determined by Epworth scale. Male gender (Odds ratio (OR): 4.00; 95% confidence intervals (CI): 1.59-10.0, p = 0.003), BMI ≥ 26 kg/m² (OR: 3.68; 95%CI: 1.59-8.49, p = 0.002), smoking (OR: 2.29; 95% CI: 1.17-4.47, p = 0.015), Epworth index > 13 (OR: 2.65; 95% CI: 1.35-5.23, p = 0.005) and duration of symptoms over 2 years (OR: 2.35; 95% CI: 1.20-4.58, p = 0.012) were significant independent predictors of OSA. In nocturnal oximetry, the lowest SpO2 (SpO2 min) and the length of registries below 90% (CT-90) were independent predictors of OSA and both correlated significantly with AHI (r = -0.49 and r = 0.46 respectively, p < 0.001). Conclusions: No single factor was usefully predictive of obstructive sleep apnea. However, combining clinical features and oximetry data may be appropriate to detect clinically significant OSA patients.

Background: The use of CPAP is the conventional therapy for the Obstructive Sleep Apnea Syndrome (OSAS). Aim To establish the proportion of OSAS patients with CPAP indication who use it in the long-term and to determine predictive factors of adherence. Patients and Methods: Structured survey through personal interview or phone call, applied to all patients who had polisomnographically documented OSAS and CPAP titration at the Pontificia Universidad Católica de Chile Sleep Disorders Center between January 1998 and November 2001. Patients were divided in "Permanent Users" (Group I) and "Non Users" (Group II). Results: Of 440 patients that fulfilled inclusion criteria, 162 (32.8%) answered the survey. Seventy percent (114/162) of these patients had used CPAP and 86% (98/114) continued to use it at the time of the interview, with a mean follow-up of 12.3 months (Group I 60.5% of the interviewed population). Group II included 64 patients (39.5% of the interviewed patients). Among the latter, 25% (16/64) stopped using CPAP due to intolerance, 25% (16/64) could not use it because of economical restrictions, 20.5% (13/64) preferred other therapies and 29.5% (15/64) merely refused treatment. Predictors of long-term use of CPAP were number of respiratory events (p <0.01), hypersomnolence (p <0.01) and age (p =0.03). Conclusions: Approximately two thirds of patients with OSAS, with an indication for CPAP, continue to use this therapy in the long term in a Chilean population. This figure is similar to other reports from abroad. It is also possible to identify predictive factors for CPAP discontinuation in this population

Tobacco smoking has increased among young women in reproductive age from developing countries but its prevalence during pregnancy is virtually unknown. This study describes the prevalence of smoking during pregnancy in a random sample of 400 mothers of low socioeconomic status from South-Santiago, Chile. The prevalence of active tobacco smoking during pregnancy was 28%. Fifty-nine percent of mothers who had never smoked were exposed to intra-domiciliary tobacco smoke during pregnancy. There was no significant difference in birth weight, height, and Apgar score between exposed and non-exposed groups. However, the newborns from mothers who were active smokers previous to pregnancy presented lower birth weight (p = 0.04) and higher frequency of low weight for gestacional age (p = 0.02) than newborns from non-smoking mothers. The prevalence of tobacco smoking during pregnancy in mothers of low socioeconomic status is as higher as that reported from developed countries. A high proportion of mothers (smokers and non-smokers) are passively exposed to tobacco smoke at home during pregnancy

El tabaquismo en mujeres jóvenes en edad fértil ha aumentado en los últimos años en países en desarrollo, pero su prevalencia en mujeres embarazadas de bajos recursos económicos es virtualmente desconocida. Este estudio describe la prevalencia del tabaquismo durante el embarazo en una muestra aleatoria de 400 madres de bajo nivel socioeconómico, atendidas en el Hospital El Pino, Santiago Sur, Chile. La prevalencia de tabaquismo durante el embarazo fue 28%. Un alto porcentaje (59%) de madres embarazadas que nunca habían fumado, estuvieron expuestas al humo del tabaco en sus hogares. No hubo una diferencia significativa entre los dos grupos en el peso, talla, puntaje de Apgar, o edad gestacional. Los recién nacidos (RN) de madres que eran fumadoras antes del embarazo presentaron menor peso de nacimiento que los RN de madres no fumadoras (p = 0,04) y mayor frecuencia de RN pequeños para edad gestacional (p = 0,02). La prevalencia de tabaquismo durante el embarazo en madres de bajo nivel socioeconómico es alta y similar a las encontradas en mujeres embarazadas de países desarrollados. Una alta proporción de las madres embarazadas tanto fumadoras como no fumadoras está expuesta al humo de tabaco en sus hogares

Background: Nasal continuous positive airway pressure therapy (CPAP) in the treatment of choice for adult obstructive sleep apnea (OSA). The diagnosis is established with polysomnography, but this study is expensive and must be repeated in those patients that require CPAP, to titrate the pressure of the therapy. Split polysomnography during one night to establish the diagnosis and titrate the pressure has been proposed to reduce costs. Aim: To assess if CPAP pressure can be adequately titrated in patients with OSA using a split-night polysomnography. Material and methods: One hundred fifty six patients with OSA were studied with split night polysomnography. CPAP pressure titration was considered adequate when there were less than five apnea/hypopnea episodes per hour, the registry time was more than 30 min, REM sleep occurred in more than 15% of the time and measurements were made in supine position. Results: An adequate titration was achieved in 80% of patients. The variables associated with an adequate titration were a higher registry time during the titration period, a higher percentage of stage III/IV or REM sleep during such period and the comfort experienced by the patient during the study. On the other hand, patients with an inadequate titration had a longer basal registry period. Conclusions: An adequate CPAP pressure can be prescribed to 80% of patients subjected to a split-night polysomnography. The basal registry period should not be longer than three hours, to allow an adequate titration lapse

Rhodococcus equi, is a grampositive intracellular bacillus, that causes infection mainly in immunocompromised hosts. We report the case of a 52 years old woman, with a systemic lupus erythematosus and a progressive 10 months evolution with cough, dyspnea, mucous-purulent sputum, occasionally hemoptysis, intermittent fever, and weight loss of 10%. With partial response to antibiotic treatment, radiological evolution of thoracic scanners evidenced the development of multiple bilateral areas of consolidation, some of them nodular. Percutaneous thoracic biopsy showed characteristic histology and microbiological analysis yielded the identification of Rhodococcus equi in both bronchoalveolar lavage and pulmonary biopsy. She received prolonged bi-associated antibiotic treatment with good clinical and radiological response. This agent must be considered in the study of immunocompromised patients that present with a prolonged evolution of pneumonia.

Rhodococcus equi, es un bacilo grampositivo intracelular que causa infecciones mayoritariamente en pacientes inmunodeprimidos. Reportamos el caso de una mujer de 52 años, en tratamiento de lupus eritematoso sistémico, con historia progresiva de 10 meses de evolución caracterizada por tos, disnea progresiva, expectoración muco-purulenta, ocasionalmente hemoptoica, fiebre intermitente, y pérdida de peso del 10%. Tuvo respuesta parcial a diversos cursos de tratamiento antimicrobiano y el seguimiento radiológico evidenció la aparición de múltiples focos de consolidación bilaterales, algunos de ellos nodulares. El estudio microbiológico de un lavado broncoalveolar y de una biopsia pulmonar percutánea permitió la identificación de R. equi y la histología de la biopsia pulmonar fue compatible. Recibió tratamiento antimicrobiano bi-asociado prolongado con buena respuesta clínica y radiológica. Se debe considerar este agente en el estudio de pacientes inmunocomprometidos que cursan con neumonías de evolución prolongada.

Background: The six minute walk test (6MW) elicits dynamic hyperinflation (DH) in severe COPD patients, which can be evaluated by reductions in inspiratory capacity (IC). Although IC is currently used to determine the effects of bronchodilators on DH during exercise tests on a cycle ergometer, its usefulness during a walking test has not been evaluated. Aim: To study the acute effects of ipratropium bromide (IB) on forced expiratory volume at l second (FEV1) and IC at rest and on DH during exercise assessed by the 6MW. Subjects and methods: Fifteen stable COPD patients were randomly allocated in a double-blind, placebo-controlled, crossover fashion to 2 treatment periods using a single dose of nebulized IB 500 mg or placebo. Spirometry, including IC, and 6MW were measured at baseline and after IB and placebo. IC was also measured 15 min after exercise. Dyspnea, oxygen saturation (SpO2) and heart rate were assessed at the end of exercise. Results: After IB, 8/15 patients exhibited a clinically significant increase in IC (<FONT FACE=Symbol>³1</FONT>0% predicted). A similar increase in FEV1 was observed in only one patient. No changes were observed with placebo. A significant increase in 6MW from baseline (p=0.007) was found after IB (45±14 m) compared to placebo (0.5±9 m), whereas dyspnea was significantly lower. Inspiratory capacity fell after 6MW with both treatments, but it reached their baseline values at 15 min after exercise only with IB. Conclusions: Our results demonstrate that IC provides additional information to conventional spirometry on the acute effects of bronchodilators and confirm its value to assess DH during a walking test (Rev Méd Chile 2003; 131: 605-612)

Background: Exercise tolerance in patients with COPD is highly variable and poorly related to airways obstruction assessed by FEV1. These patients develop dynamic hyperinflation (DH) during an incremental exercise test which can be evaluated through a reduction in inspiratory capacity (IC). Aim: to evaluate: a) if the six minute walking test (6 MWD) induce DH reducing IC, b) if the reduction in IC is related to tidal expiratory flow limitation at rest (FL). Subjects and methods: Thirty eight stable COPD patients (28 FL and ten non FL during resting breathing, determined by the negative pressure technique). Inspiratory capacity was measured before and immediately after the 6 MWD test. Dyspnea, SpO2 and heart rate were measured before and after the test. Results: Inspiratory capacity was lower in FL patients as compared to patients without FL (p <0,005). Although no differences were found between groups in 6 MWD, dyspnea and HR, a significant reduction in IC after the walking test was observed only in FL patients (p <0,0001). In addition, SpO2 fell significantly (p <0,0001) after walking in the same group. Conclusions: Our results demonstrate that a moderate exercise such as the walking test induces DH and hypoxemia in patients with COPD and FL and stresses the importance of assessing DH by measuring IC in these patients (Rev Méd Chile 2001; 129: 1171-78)