Paper 3 Answers
James Day, Amy Thomson, Tamsin McAllister, Nawal Bahal in Get Through, 2014
There are a number of lung volumes that represent how much air is present in the lungs at different points in the breathing cycle. Lung capacities are the sum of a number of different lung volumes. All lung volumes can be measured by a simple spirometer except the residual volume (RV) and hence the functional residual capacity (FRC), the sum of the RV and the expiratory reserve volume. To measure the RV and hence the FRC we can use either the helium dilution technique or a body plethysmograph. The dilution technique works when using helium because it is almost insoluble in blood. A drawback of this technique is that the helium can only be diluted in the air in the lungs that can be ventilated. If there is significant air trapping then the helium will not be diluted in these portions. Hence this technique is not very accurate in those patients with obstructive airway diseases. A more accurate technique in these cases is to use the body plethysmograph, which utilizes Boyle’s law to calculate the lung volume by detecting a pressure change in an airtight box. When using the helium technique the patient is connected to the spirometer at the end of a normal breath to ensure the FRC is being measured and not other lung volumes.
Single Best Answer Questions
Vivian A. Elwell, Jonathan M. Fishman, Rajat Chowdhury in SBAs for the MRCS Part A, 2018
You request preoperative lung function tests on a patient with longstanding emphysema. What is true of the functional residual capacity?It is the sum of the tidal volume and residual volumeIt is the sum of the inspiratory reserve volume, the expiratory reserve volume, and the tidal volumeIt can be measured directly by spirometryIt is the sum of the residual volume and the expiratory reserve volumeIt is the volume of air that remains in the lung after forced expiration
Effect of Bronchodilators and Inhaled Corticosteroids on Dyspnea in Chronic Obstructive Pulmonary Disease
Donald A. Mahler, Denis E. O’Donnell in Dyspnea, 2014
Our understanding of the interface between pathophysiological impairment and disability has increased considerably in recent years (see Chapter 5). Although the most obvious abnormality in COPD is expiratory flow limitation, the major mechanical consequence is evident in inspiration as a result of the negative effects of pulmonary hyperinflation. As ventilation increases during exercise in flow-limited patients, further acute-on-chronic dynamic hyperinflation occurs, which further amplifies the derangements of ventilatory mechanics that are present at rest [5–10]. The diminished inspiratory capacity (IC) as a result of lung hyperinflation restricts the ability to expand tidal volume (VT) appropriately during exercise because of the relatively reduced inspiratory reserve volume (IRV). Moreover, at high lung volumes, the inspiratory muscles are naturally weakened and are burdened with increased elastic and inspiratory threshold loading. The net effect of breathing close to total lung capacity is an increased contractile muscle effort requirement for any given increase in ventilation during exercise compared with healthy individuals. In the hyperinflated COPD patient, there is, therefore, an increased disparity between the increased neural drive to breathe during exercise and the mechanical response of the respiratory system, which is blunted (i.e., neuromechanical uncoupling). The intensity of activity-related dyspnea in flow-limited patients has been found to be closely associated with the extent of mechanical constraints on VT expansion (i.e., the VT/IC ratio) during exercise [6–10].
Cardiorespiratory repercussions according to the abdominal circumference measurement of men with obstructive respiratory disorder submitted to respiratory physiotherapy
Published in Physiotherapy Theory and Practice, 2018
Bruno Martinelli, Valéria Amorim Pires Di Lorenzo, Robison José Quitério, Alexandre Ricardo Pepe Ambrozin, Eduardo Aguilar Arca, Maurício Jamami
The higher values of BMI and AC corresponded to lower values of FVC and FEV1. This may be due to increased elastic recoil of the chest wall by the imbalance of structures, mainly to higher levels of tissue in the chest wall. Moreover, diaphragmatic expansion is also mechanically affected (Steier et al., 2009). The compliance of the respiratory system is reduced due to the fact that respiration is performed at abnormally low lung volumes. Normal breathing starts at low-end expiratory volumes where the lungs are less compliant and the airways are prone to collapse during expiration (Behazin, Jones, Cohen, and Loring, 2010). However, pulmonary compression with reduced expiratory reserve volume leads to a compensatory increase in the inspiratory reserve volume (IRV) in an attempt to maintain constant vital capacity (VC) (Costa et al., 2008). The accumulation of adipose tissue along with probable chest tightness/rigidity caused by advanced age are limiting factors that compromise chest expansion (Sharma and Goodwin, 2006; Steier et al., 2009). It can be inferred that these aforementioned mechanisms were probably those which contributed to the reduction of the thoracoabdominal AI at all time periods in the CArisk group.
The safety and sustainability of bottle-pep therapy in pediatric patients with cystic fibrosis
Published in Physiotherapy Theory and Practice, 2023
Büşra Nur Fındık, Özge Kenis- Coskun, Evrim Karadağ-Saygı, Yasemin Gökdemir, Almala Pınar Ergenekon, Bülent Karadağ
Pulmonary function tests (PFT) are objective tests used to diagnose, manage and monitor patients with a variety of respiratory diseases. Spirometry is a kind of pulmonary function test that measures the rate of changing lung volumes during forced breathing maneuvers. At the current study pulmonary function tests were performed using a spirometer (WinspiroPRO 2.8 MIR, Rome, Italy) by the same technician at the pediatric pulmonology clinic in accordance with international standards (Graham et al., 2019). Patients were seated in an upright position and a nose clip was applied. The test was performed by blowing into the reader part of the spirometer with a forced expiration maneuver after a deeply inspiration. The test was repeated at least three times and three acceptable spirometry values were obtained. The largest FEV1, FVC values and their ratio (FEV1/FVC) were recorded. FEF 25–75 values from the maneuver with the largest sum of FEV1 and FVC were recorded.
Risk factors for impaired pulmonary function and cardiorespiratory fitness in very long-term adult survivors of childhood acute lymphoblastic leukemia after treatment with chemotherapy only*
Published in Acta Oncologica, 2018
Ole Henrik Myrdal, Adriani Kanellopoulos, Jon R. Christensen, Ellen Ruud, Elisabeth Edvardsen, Johny Kongerud, Liv Ingunn Sikkeland, May B. Lund
Pulmonary function tests included dynamic spirometry, determination of static lung volumes and single breath gas diffusing capacity (DLCO). Spirometric variables were forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and the ratio FEV1/FVC. Lung volume variables were total lung volume (TLC) and residual volume (RV). Gas transfer variables were transfer factor for carbon monoxide, DLCO and DLCO divided by alveolar volume, VA. DLCO measurements were also corrected for Hb. All measurements were performed with the Vmax Pulmonary Function Unit (VIASYS Respiratory Care Inc, Yorba Linda, CA) and according to the guidelines recommended by the European Respiratory Society guidelines (ERS) [26–28]. The pulmonary function variables were expressed in absolute values and as a percentage of predicted normal values. Reference values were those recommended by ERS [29]. Obstructive impairment was defined as FEV1/FVC <0.7 according to The Global Initiative for Chronic Obstructive Lung Disease [30]. Restrictive impairment and impairment in DLCO were defined as <80% of predicted. These cutoff points correspond to the lower 5th percentiles in the reference material and in line with ERS recommendations [29].
Related Knowledge Centers
- Altitude Sickness
- Breathing
- Lung
- Tidal Volume
- Spirometer
- Respiratory Rate
- Functional Residual Capacity
- Thoracic Diaphragm
- Minute Ventilation
- Pulmonary Function Testing