Lung Volumes and Capacities Quiz

Vital capacity (VC) is the maximum amount of air that can be exhaled after a full inspiration, while total lung capacity (TLC) is the maximum amount of air that the lungs can hold.

Tidal volume (TV) is the normal amount of air inhaled during relaxed breathing, while inspiratory reserve volume (IRV) is the additional air that can be forcibly inhaled on top of the tidal volume.

Functional residual capacity (FRC) is composed of the expiratory reserve volume (ERV) and residual volume (RV). ERV is the additional air that can be forcibly exhaled after a normal breath, while RV is the air remaining in the lungs even after maximum exhalation.

<p>Residual volume (RV) ensures that the lungs remain partially inflated even after a full exhalation, preventing collapse and maintaining a minimal level of gas exchange.</p> Signup and view all the answers

<p>2,500 mL. IC = TV + IRV, so IRV = IC - TV = 3,000 mL - 500 mL = 2,500 mL.</p> Signup and view all the answers

<p>3,500 mL. VC = TV + IRV + ERV. We know TV is 500 mL. So, 4,500 mL = 500 mL + IRV + 1,000 mL, which means IRV = 3,500 mL.</p> Signup and view all the answers

<p>FRC is the total volume of air remaining in the lungs after a normal expiration, while RV is the air remaining in the lungs even after a maximum exhalation. FRC includes both RV and expiratory reserve volume (ERV).</p> Signup and view all the answers

<p>Lung volumes and capacities provide valuable information about lung function and can indicate potential respiratory issues. They are used to diagnose diseases, monitor treatment progress, and assess overall respiratory health.</p> Signup and view all the answers

<p>Helium dilution, nitrogen washout, and body plethysmography.</p> Signup and view all the answers

<p>Because RV cannot be exhaled.</p> Signup and view all the answers

<p>The patient is assumed to have no Helium in their lungs at the beginning of the test.</p> Signup and view all the answers

<p>A known volume and concentration of Helium is introduced to the patient's lungs, and its dilution is measured as it mixes with the patient's lung volume.</p> Signup and view all the answers

<p>The equilibration time indicates the distribution of ventilation in the patient's lungs.</p> Signup and view all the answers

<p>The resting expiratory level of the FRC (functional residual capacity).</p> Signup and view all the answers

<p>It assumes that nitrogen concentration in the lungs is 78%, in equilibrium with the atmosphere, before the test begins.</p> Signup and view all the answers

<p>The patient inhales 100% oxygen, which replaces the nitrogen in their lungs, and the amount of nitrogen exhaled is measured.</p> Signup and view all the answers

<p>Because the patient inhales 100% oxygen and exhales the nitrogen mixture.</p> Signup and view all the answers

<p>Helium dilution uses a closed, rebreathing circuit, where Helium is introduced and its dilution is measured. Nitrogen washout uses an open circuit, where the patient exhales the nitrogen replaced by oxygen.</p> Signup and view all the answers

<p>During the panting maneuver, a decrease in cabinet volume leads to an increase in thoracic volume. This is due to the pressure changes within the chamber, as described by Boyle's law.</p> Signup and view all the answers

<p>The simplified equation used to calculate TCV during panting is: TCV = PB X V/P, where PB represents barometric pressure, V is the volume change, and P is the pressure change.</p> Signup and view all the answers

<p>The plethysmography technique relies on Boyle's law, which states that the product of pressure and volume remains constant for a given mass of gas at a constant temperature.</p> Signup and view all the answers

<p>The plethysmography technique measures the volume of all compressible gases in the thorax, including gas trapped in the airways, behind airway instructions, or in the pleural space.</p> Signup and view all the answers

<p>The patient sits in the chamber and breathes normally through a mouthpiece until they reach their functional residual capacity (FRC). The shutter is then closed at the end of an expiration for 2-3 seconds to allow for measurements.</p> Signup and view all the answers

<p>CO and O2 have similar molecular weights and solubility coefficients, meaning they have comparable characteristics in terms of their size and ability to dissolve in fluids.</p> Signup and view all the answers

<p>CO chemically combines with hemoglobin (Hb) in a similar way to oxygen, but it has a much higher affinity for Hb, leading to a stronger binding.</p> Signup and view all the answers

<p>Due to its high affinity for Hb, CO diffuses rapidly into the pulmonary blood, effectively displacing oxygen from Hb molecules.</p> Signup and view all the answers

<p>Obstructive lung disease can result in an increased total lung capacity (TLC) and functional residual capacity (FRC).</p> Signup and view all the answers

<p>The high affinity of CO for Hb means that it binds to Hb more readily and strongly than oxygen. This leads to a higher concentration of CO bound to Hb, reducing the oxygen-carrying capacity of the blood.</p> Signup and view all the answers

<p>The single-breath technique, also known as the modified Krogh method, involves the patient exhaling completely to residual volume (RV) and then rapidly inhaling to total lung capacity (TLC) a volume of air containing a small concentration of carbon monoxide (CO) and helium (He). The patient holds their breath for 10 seconds and then exhales rapidly at least 1 liter of the gas mixture. The diffusing capacity (DLCO) is calculated based on the concentration of CO in the expired air and the partial pressure of CO in the alveoli.</p> Signup and view all the answers

<p>The diffusion of gases in the lungs is affected by factors such as the volume of gas transferred into the lungs, the partial pressure of the gas in the alveolus (P1), and the partial pressure of the gas in the capillary (P2).</p> Signup and view all the answers

<p>Carbon monoxide (CO) is used as the transfer gas in DLCO measurement because it is similar to oxygen (O2) in important ways, such as the way it binds to hemoglobin and its tendency to diffuse across the alveolar-capillary membrane. This makes it a reliable indicator of the overall lung diffusing capacity.</p> Signup and view all the answers

<p>The three main techniques used to measure diffusing capacity are the single-breath technique (DLCO-SB), the steady-state technique, and rebreathing techniques.</p> Signup and view all the answers

<p>The diffusing capacity of the lung (DLCO) is typically expressed in milliliters per minute per millimeter of mercury (ml/min/mmHg) under standard temperature and pressure dry (STPD) conditions.</p> Signup and view all the answers

<p>The formula for calculating DLCO = VCO/PACO, where VCO is the volume of carbon monoxide transferred and PACO is the partial pressure of CO in the alveoli.</p> Signup and view all the answers

<p>DLCO can be affected by various lung diseases, including restrictive lung diseases, obstructive lung diseases, and acute and chronic lung diseases. It is often decreased in restrictive lung diseases due to reduced lung volume and surface area for gas exchange. In obstructive lung diseases, DLCO can be decreased due to airflow obstruction and thickening of the alveolar-capillary membrane, which reduces diffusion efficiency.</p> Signup and view all the answers

<p>Factors that can affect the reliability of a DLCO test include the repeatability of the test, the time allowed between tests (at least 4 minutes), the patient's ability to cooperate and follow instructions, and the equipment used for the test.</p> Signup and view all the answers

<p>Restrictive lung diseases are characterized by a decreased lung volume, which limits the amount of air that can be inhaled and exhaled. This typically results in a decreased total lung capacity (TLC) and inspiratory capacity (IC).</p> Signup and view all the answers

<p>The single-breath DLCO (DLCO-SB), also known as the modified Krogh method, involves a single breath hold, while multi-breath DLCO involves multiple breaths. In multi-breath DLCO, the patient breathes a mixture of gases for several minutes, allowing for a steady-state measurement of diffusing capacity.</p> Signup and view all the answers

<p>The Steady-State Technique measures DLCO while the subject is breathing normally, collecting exhaled air over two minutes. The Rebreathing Technique involves a specific gas mixture being rebreathed until equilibrium is reached, then the exhalation washes out the mixture for analysis. Both techniques involve different approaches to measuring the diffusion capacity of the lung (DLCO).</p> Signup and view all the answers

<p>Reproducibility is crucial for ensuring reliable and accurate DLCO measurements. Consistency in results allows for meaningful comparisons over time and between different individuals, aiding in diagnosis and monitoring of lung health.</p> Signup and view all the answers

<p>An acceptable DLCO test is reproducible to within 10% or 3 ml CO ml/min/mmHg, whichever is greater.</p> Signup and view all the answers

<p>The gas mixture with 0.1% CO allows for a safe and measurable amount of carbon monoxide to be inhaled during the test. It enables accurate measurement of the subject's diffusion capacity of the lung without posing significant health risks.</p> Signup and view all the answers

<p>The Douglas bag is used to collect the exhaled air of the subject during the last two minutes of steady-state breathing. This collected air is then sampled for analysis of the CO concentration.</p> Signup and view all the answers

<p>The formula represents the calculation of the diffusion capacity of the lung at steady-state (DLCO-SS) using the volume of carbon monoxide absorbed at standard temperature and pressure (VCO) divided by the partial pressure of carbon monoxide in the alveolar air (PACO).</p> Signup and view all the answers

<p>The washout phase involves the subject inhaling regular air after rebreathing the gas mixture. This process washes out the mixture from the lungs, allowing for a more accurate analysis of the carbon monoxide and helium concentrations in the exhaled air.</p> Signup and view all the answers