Papel de la prueba de esfuerzo cardiopulmonar en el diagnóstico de la disnea crónica de origen desconocido / Role of the cardiopulmonary stress test in the diagnosis of chronic dyspnoea of unknown aetiology

FUNDAMENTO: El objetivo principal de este trabajo ha sido describir el espectro y frecuencia de causas que provocan disnea de origen desconocido en nuestro medio mediante la realización de la prueba de esfuerzo cardiopulmonar y demostrar su utilidad en el diagnóstico de la disnea crónica, tanto para esclarecer su etiología como para orientar las pruebas posteriores. MÉTODOS: Se ha realizado un estudio descriptivo durante cinco años de los enfermos remitidos a nuestro servicio por disnea crónica de origen desconocido. Todos presentaban una historia clínica, exploración física y pruebas complementarias básicas que no aclaraban su etiología. Se les realizó una prueba de esfuerzo cardiopulmonar, registrándose una serie de parámetros funcionales y arrojando finalmente un diagnóstico ergométrico siguiendo el algoritmo de Wasserman et al.1 RESULTADOS: Fueron incluidos 178 pacientes (92 hombres; edad media 42,5 ± 16,7 años). Por orden de frecuencia los diagnósticos obtenidos fueron: normal o disnea psicógena (71,9%), hiperreactividad bronquial (8,4%), limitación ventilatoria (6,7%),sobrepeso y sedentarismo (3,9%), crisis de HTA (3,9%), limitación cardiocirculatoria (3,4%) y alteración vascular pulmonar (1,7%).No encontramos diferencias entre sexos o entre distintos grupos de edad en cuanto a los diagnósticos ergométricos. CONCLUSIONES: Hemos comprobado que en la mayoría delos casos un diagnóstico de normalidad ha permitido excluir la existencia de enfermedad significativa. Algunos pacientes cuyos resultados fueron patológicos precisaron la realización de nuevas pruebas, sin embargo, al orientar el diagnóstico, el test de esfuerzo permitió hacer una selección más precisa de las mismas, con los consiguientes ahorros en tiempo, dinero y molestias a los pacientes

INTRODUCTION: The principal goal of this study has been to describe the spectrum and frequency of diseases presenting as unexplained dyspnea in our area by means of performing graded cardiopulmonary exercise test and demonstrate its utility in the diagnosis of chronic dyspnea, so much to clear up its etiology as to guide further tests. METHODS: A descriptive study has been performed for five years based in the patients referred to our service with chronic explained dyspnea. All of them presented clinical history, physical examination and basic complementary tests that didn’t clear up its etiology. A graded cardiopulmonary exercise test was performed, recording a series of functional parameters and yielding finally an ergometric diagnosis following the algorithm by Wasserman et al.1RESULTS: 178 patients were entered (92 male; mean age 42,5± 16,7 years). Obtained diagnosis in order or frequency were: normal or psichogenic dyspnea (71,9%), bronchial hyper reactivity (8,4%), pulmonary limitation (6,7%), overweight and deconditioning(3,9%), hypertensive crisis (3,9%), cardiocirculatory limitation(3,4%) and pulmonary vascular alterations (1,7%). We didn’t found significant differences between both sexs or between different groups of age as for the ergometric diagnosis. CONCLUSIONS: After assessing all the results of our study, we saw that in most of cases a normal diagnosis could reject the existence of a significant disease. Some patients whose results were pathological needed the performing of new tests, however, the cardiopulmonary exercise test, thanks to guiding the diagnosis, allowed a more correct selection of them, with the consequent savingsin time, money and bothers to the patients

A descriptive study of second primary malignancies associated to breast cancer in a mexican Hispanic population.

Breast cancer is the second most frequent tumor in Mexico. Patients diagnosed with this cancer have a higher risk of developing a second malignancy. The objective of our study was to see the frequency, types of second cancers, and its impact on survival, in order to be able to deliver a proper and efficient follow up to these patients, because our patients differ from the population of breast cancer in the rest of the world. Our patients are younger and therefore at higher risk. The clinical records of breast cancer patients treated at the Instituto Nacional de Cancerologia Mexico from 1983 to 1992 were reviewed. In 1370 evaluable patients, 77 (5.6%) developed a second neoplasm, of those, 56 (72.7%) in the contralateral breast and 21 in other sites (27.3%), thyroid was the most frequent followed by ovary and endometrium. Mean age of the patients was 51.5 yr, 45.5 for the other breast and 55.5 for other malignancies (p = 0.01). Median survival for all the group was of 180 mo (3-238). Patients were significantly younger in the contralateral breast group, although all our breast cancer patients are younger. The most frequent second malignancy after the other breast, was thyroid followed by ovary and endometrium with similar survival for both groups.

Effects of CO2 anaesthesia on central nervous system activity in swine.

The objective of the study was to examine the changes in central nervous system (CNS) activity and physical behaviour during induction and awakening from CO2 anaesthesia. Two studies, each using pigs immersed into 90% CO2 gas for a period of 60 s were performed. In study 1, we monitored middle latency auditory evoked potentials (changes in latencies, amplitudes and a depth of anaesthesia index), electroencephalographic parameters (delta, theta, alpha and beta electroencephalographic power and 95% spectral edge frequency) and heart rate; and in study 2, we monitored body movements and arterial and venous partial pressure of CO2 and O2. No behavioural signs of distress were observed during the early part of the induction. The swine exhibited muscular activity from 13-30 s after induction-start as well as during awakening from anaesthesia, possibly because of a transitory weaker suppression of the brain stem than of the cortex. The CNS and blood gas parameters started to change from the very start of induction. The CNS suppression lasted only approximately one minute after the end of the induction period. The two studies indicated a good temporal relationship between changes in amplitude, depth of anaesthesia index, spectral edge frequency, and arterial PCO2 during the induction period.

Middle-latency auditory evoked potentials during induction of thiopentone anaesthesia in pigs.

A method is described for measuring middle-latency auditory evoked potentials (MLAEP) in consciously awake, non-sedated pigs during the induction of thiopentone anaesthesia (0.6 ml/kg, 2.5% thiopentone solution). It was done by using autoregressive modelling with an exogenous input (ARX). The ability to perceive pain during the induction was compared with (1) the changes in latencies and amplitudes of the MLAEP, (2) the change in a depth of anaesthesia index based on the ARX-model and (3) the change in the 95% spectral edge frequency. The pre-induction MLAEP was easily recordable and looked much like the one in man, dogs and rats. The temporal resolution in the ARX method was sufficiently high to describe the fast changes occurring during induction of thiopentone anaesthesia. As previously reported from studies in man, dogs and rats, induction of thiopentone anaesthesia resulted in significantly increased latencies and decreased amplitudes of the MLAEP trace as well as in a significantly reduced depth of anaesthesia index and spectral edge frequency. None of the changes, however, related well to the ability to react to a painful stimulus. Whether an ARX-based depth of anaesthesia index designed especially for pigs might be better than the present index (designed for man) for assessing depth of anaesthesia must await the results of further studies.

Spontaneous vesicle formation in aqueous mixtures of single-tailed surfactants.

Spontaneous, single-walled, equilibrium vesicles can be prepared from aqueous mixtures of simple, commercially available, single-tailed cationic and anionic surfactants. Vesicle size, surface charge, or permeability can be readily adjusted by varying the ratio of anionic to cationic surfactant. Vesicle formation apparently results from the production of anion-cation surfactant pairs that then act as double-tailed zwitterionic surfactants. These vesicles are quite stable in comparison to conventional vesicles prepared by mechanical disruption of insoluble liquid crystalline dispersions.