To the Editor: First of all we would like to thank Mayoralas et al1 for their comments on the article published in Archivos de Bronconeumología2. Our basic aim was educational, and we particularly wanted to stress the need to monitor the pulmonary function of patients with motor neuron diseases. The case we described seemed to us to be a good example of monitoring for the duration of the illness and highlighted the different events affecting patients suffering from amyotrophic lateral sclerosis (ALS). It is true that we did not provide data on pulmonary gas exchange, but this was for editorial reasons not medical ones. The patient in question maintained correct arterial blood gas parameters until a third of the way into the illness. In 1993 hypercapnia appeared and both the patient and his family were consulted about the possibility of using noninvasive ventilation. This option was rejected, as was the possibility of creating a tracheostomy when this was proposed.

We agree that it is necessary to anticipate the events related to respiratory failure and therefore have recently included some parameters that measure ineffective coughing3. In the case we described these data were not at our disposal and so they were not included. However, conventional tests (spirometry, maximal respiratory pressures, maximum voluntary ventilation, blood gas measurement, etc.) in good hands, still provide relevant clinical information that we cannot and should not ignore4.

The introduction of procedures like noninvasive mechanical ventilation, used by experienced pneumologists, has allowed some ALS patients to live longer and, more importantly, to improve their quality of life. ALS is a complex illness and requires comprehensive treatment based on interpreting clinical and functional variables and above all on establishing a relationship between the doctor and the patient. Family relationships are also important in many cases. The need for a comprehensive approach, especially since the introduction of new forms of treatment using noninvasive ventilation, has led pneumologists and neurologists to establish a very fruitful dialogue that is clearly of great benefit to the patient. Such dialogue often arises from the study of pulmonary function, and for that reason we must bear in mind the correct indication for these tests and their interpretation.