The Respiratory Physiology Laboratory of the Pulmonology Department has existed since the outset of Santa Maria Hospital. The Sleep Studies Laboratory was set up during the leadership of Professor Manuel Freitas e Costa (1997), initially with one polysomnograph, and, later, two.

In 2008, under the direction of Professor Bugalho de Almeida, the Respiratory Physiopathology Unit was completely renovated, and two distinct areas were created: one for the study of the respiratory function, and the other for the study of sleep-related breathing disorders. The Respiratory Physiopathology Laboratory has two plethysmographs that enable the performance of several techniques to assess the respiratory function, such as spirometry, plethysmography, diffusion studies, respiratory pressures, study of the respiratory centre, and also conducting bronchoprovocation tests. In addition, there is also a portable spirometer with the purpose of evaluating specific situations, such as diaphragmatic dysfunction, or to address severe cases of patients who do not tolerate the sitting position. In order to evaluate stress, the laboratory has not only the inescapable six-minute walk test, but also a cycle ergometer.

Just to give an example, the Respiratory Physiopathology Laboratory carries out over 6000 respiratory function tests per year. Finally, the lab is the only one, in terms of pneumonology practiced in the country, to conduct the provocation of hypoxia test to study the impact of altitude on gas exchange, particularly when air travelling, which is common practice these days.

The Sleep Studies Laboratory conducts the entire study of sleep-related breathing disorders. To that effect, it has six rooms equipped with polysomnographs with synchronised video, and two portable devices used in those cases that cannot be studied in this area, and four oximeters for performing limited studies.

In addition to basic sleep studies, the Laboratory also performs the continuous monitoring of non-invasive blood pressure and cardiac output through the analysis of the pulse wave (Nexfin HD), as well as recording CO2 transcutaneously. On the other hand, Nexfin HD is still used in patients with respiratory disease in order to analyse the effects of forced ventilatory manoeuvres on hemodynamic values. A collaboration protocol has currently been established with UTIC (HSM) to evaluate these data in patients after acute myocardial infarction.

Following the award of a research grant from the Foundation for Science and Technology, the Laboratory purchased a pupillograph in partnership with the IMM. It is the only device of its kind in the country and it allows to objectively quantify excessive daytime sleepiness. Over one thousand sleep studies are conducted per year.

From a clinical standpoint, the Respiratory Physiopathology Laboratory has a partnership with the Neurology Department to evaluate neuromuscular patients, and with the Obesity Clinic of the Endocrinology Department, both in terms of functional assessment and for performing sleep polygraph studies in patients referred for bariatric surgery.

Thanks to this technical potential, both laboratories can meet the training requirements of the medical degree at undergraduate and postgraduate levels, in addition to the training needs of students of the degree in cardiopulmonology. There are three assistants of the Faculty of Medicine of Lisbon and three assistants of the Higher College of Health Technologies of Lisbon.

In the last two years, the laboratories have had six students of the Integrated Master Degree in Medicine, who conducted research projects for their theses in the fields of Sleep Medicine and Respiratory Function. Two of these theses were approved by the Office for the Support of Scientific Research (GAPIC) and gave rise to posters submitted at national and international conferences.

With regard to postgraduate education, the Respiratory Function Laboratory is used for the completion of the mandatory internships of the Pulmonology and Immunoallergology specialties. The Sleep Studies Laboratory has been responsible for the training of interns of the department and of other areas, enabling them to acquire competencies in an increasing important area of Portuguese medicine.

Over the years the Unit has enabled the writing of a few (3) master degree theses as part of the Master Degree in Sleep Sciences of the Faculty of Medicine of Lisbon and one in Respiratory Physiopathology. Two doctoral theses are currently in progress.

In 2011, the Sleep Laboratory started a partnership with the IMM for the prospective study on the relevance of “Clock-Genes” in Sleep Apnoea.

In November 2011, the Sleep Studies Laboratory was invited to participate in the European Sleep Apnoea Data Base (ESADA), being the first sleep laboratory in Portugal involved in this project.

In the last seven years, the unit’s scientific output has been the following:

Photo courtesy of Office of Communication and Public Relations CHLN-HSM

Dr João Valença
Respiratory Physiology Unit
(Respiratory Physiology Laboratory and Sleep Studies Laboratory)