Pere Casan Clarà

Depósito pulmonar de partículas inhaladas

Inhaled medication is the first-line treatment of diseases such as asthma or chronic obstructive pulmonary disease. Its effectiveness is related to the amount of drug deposited beyond the oropharyngeal region, the place where the deposit occurs and its distribution (uniform or not). It is also important to consider the size of the inhaled particles, the breathing conditions, the geometry of the airways and the mucociliary clearance mechanisms. Currently, mathematical models are being applied to describe the deposition of inhaled drugs based on the size of the particles, the inspiratory flow and the anatomical distribution of the bronchial tree. The deposition of particles in the small airways gets maximum attention from pharmaceutical companies and is of great interest as it is related with a better control in patients receiving these drugs.Inhaled medication is the first-line treatment of diseases such as asthma or chronic obstructive pulmonary disease. Its effectiveness is related to the amount of drug deposited beyond the oropharyngeal region, the place where the deposit occurs and its distribution (uniform or not). It is also important to consider the size of the inhaled particles, the breathing conditions, the geometry of the airways and the mucociliary clearance mechanisms. Currently, mathematical models are being applied to describe the deposition of inhaled drugs based on the size of the particles, the inspiratory flow and the anatomical distribution of the bronchial tree. The deposition of particles in the small airways gets maximum attention from pharmaceutical companies and is of great interest as it is related with a better control in patients receiving these drugs.

Home Mechanical Ventilation through Mask: Monitoring Leakage and Nocturnal Oxygenation at Home

Background: Leakage is common in patients receiving home mechanical ventilation (HMV) via a face mask. Although pressure ventilators have partial compensatory capacity, excessive leakage can compromise the effectiveness of treatment. Home ventilators are equipped with built-in software which provides information on leakage. However, the values of leakage and their effects in routine clinical practice are currently little known. Objective: To measure leakage in stable patients on nocturnal HMV and its impact on treatment effectiveness. Methods: Consecutive outpatients on HMV were recruited. Nocturnal pulse oximetry was performed at home and leakage was measured using the ventilator’s built-in software. We measured: mean SpO2, percentage of time with SpO2 <90% (T90), mean leakage (meanL), maximum leakage (maxL), and minimum leakage (minL) during the ventilation session. We estimated ventilator capacity to compensate for leakage according to inspiratory positive airway pressure and divided the patients into two groups: those with leak compensation and those without. Results: The study included 41 patients [mean age, 64 years (SD 11.9); 23 (56%) women]. Nocturnal pulse oximetry showed an SpO2 of 94% (±2.9) and a T90 of 10% (±21.7). Leakage (in l/min) was: meanL, 32.2 (±15.3); maxL, 64.8 (±28.5), and minL, 18.8 (±10.6). Seven cases (17%) had leakage greater than the ventilator compensatory capacity, but no significant difference in SpO2 or T90 was observed between patients with or without leak compensation. Conclusions: A wide variation between maxL and minL was observed in our series; 17% of cases had higher leakage values than the compensatory capacity of the ventilator, but this did not affect nocturnal oxygenation.Background: Leakage is common in patients receiving home mechanical ventilation (HMV) via a face mask. Although pressure ventilators have partial compensatory capacity, excessive leakage can compromise the effectiveness of treatment. Home ventilators are equipped with built-in software which provides information on leakage. However, the values of leakage and their effects in routine clinical practice are currently little known. Objective: To measure leakage in stable patients on nocturnal HMV and its impact on treatment effectiveness. Methods: Consecutive outpatients on HMV were recruited. Nocturnal pulse oximetry was performed at home and leakage was measured using the ventilator’s built-in software. We measured: mean Sp O 2 , percentage of time with Sp O 2 ! 90% (T90), mean leakage (meanL), maximum leakage (maxL), and minimum leakage (minL) during the ventilation session. We estimated ventilator capacity to compensate for leakage according to inspiratory positive airway pressure and divided the patients into

Aplicaciones de la dinámica de fluidos computacional a la neumología

Computational Fluid Dynamics (CFD) is a computer-based tool for simulating fluid movement. The main advantages of CFD over other fluid mechanics studies include: substantial savings in time and cost, the analysis of systems or conditions that are very difficult to simulate experimentally (as is the case of the airways), and a practically unlimited level of detail. We used the Ansys-Fluent CFD program to develop a conducting airway model to simulate different inspiratory flow rates and the deposition of inhaled particles of varying diameters, obtaining results consistent with those reported in the literature using other procedures. We hope this approach will enable clinicians to further individualize the treatment of different respiratory diseases.

Pruebas de función pulmonar en la fibrosis pulmonar idiopática: ¿más allá de la espirometría?

Since 1846, when John Hutchinson performed the first spirometry in London, the measurement of the air that can be mobilized during a maximum respiration has become the gold standard for the study of lung function.1 Dr. Hutchinson gave the name “vital capacity” to the volume of air that is mobilized in one deep expiration made after a maximum inspiration, and observed that individuals with lower values died prematurely. In 1947 Tiffeneau and Pinelli introduced the concept of velocity of the expired air,2 and since then both values, vital capacity (VC) and maximum expired volume in 1 s (MEVS or FEV1) have been integral parameters in the determination of respiratory function. Lung function tests in patients with a diagnosis of idiopathic pulmonary fibrosis (IPF) show the disease as a restrictive-type change impacting moderately on CO transfer (DLCO) with moderate hypoxemia and hypocapnia at rest, which, in the more advanced stages, develops into frank respiratory failure.3,4 International recommendations on the diagnosis and follow-up of IPF underline the importance of lung function testing in the control of this disease.5 The most recent clinical trials for the introduction of new drugs for treating this entity have adopted forced vital capacity (FVC) and DLCO as primary variables for confirming clinical efficacy.6,7 Nevertheless, the follow-up and control of IPF is an area where various authors are introducing new concepts and variables that better relate patient symptoms to prognosis, an essential step in a disease that carries such a heavy mortality burden. This has gradually led to the introduction of more complex determinations, including “total lung capacity”, “functional residual capacity”, “maximal exercise tolerance”, “pulmonary artery pressure”, etc., or the quantification of radiological images from new multidetector high-resolution computed tomography (HRCT) equipment. It is not surprising, then, that efforts are being made to introduce