Schibler A, Henning R (2001) Measurement of functional residual capacity in rabbits and children using an ultrasonic flow meter. Larsson A, Linnarsson D, Jonmarker C, Jonson B, Larsson H, Werner O (1987) Measurement of lung volume by sulfur hexafluoride washout during spontaneous and controlled ventilation: further development of a method. Jonmarker C, Jansson L, Jonson B, Larsson A, Werner O (1985) Measurement of functional residual capacity by sulfur hexafluoride washout. Intensive Care Med 33: 2109–2115Įast TD, Wortelboer PJ, van Ark E, et al (1990) Automated sulfur hexafluoride washout functional residual capacity measurement system for any mode of mechanical ventilation as well as spontaneous respiration. Anesthesiology 41: 605–607ĭi Marco F, Rota Sperti L, Milan B, et al (2007) Measurement of functional residual capacity by helium dilution during partial support ventilation: in vitro accuracy and in vivo precision of the method. Suter PM, Schlobohm RM (1974) Determination of functional residual capacity during mechanical ventilation. Intensive Care Med 30: 282–289Ĭhiumello D, Cressoni M, Chierichetti M, et al (2008) Nitrogen washout/washin, helium dilution and computed tomography in the assessment of end expiratory lung volume. Patroniti N, Bellani G, Manfio A, et al (2004) Lung volume in mechanically ventilated patients: measurement by simplified helium dilution compared to quantitative CT scan. Weaver LJ, Pierson DJ, Kellie R, Bonner B, Craig KC (1981) A practical procedure for measuring functional residual capacity during mechanical ventilation with or without PEEP. Macnaughton PD, Evans TW (1994) Measurement of lung volume and DLCO in acute respiratory failure. Comparison of a computerized open nitrogen washout method with a closed helium dilution method. Ibanez J, Raurich JM, Moris SG (1983) Measurement of functional residual capacity during mechanical ventilation. Heldt GP, Peters RM (1978) A simplified method to determine functional residual capacity during mechanical ventilation. This process is experimental and the keywords may be updated as the learning algorithm improves. These keywords were added by machine and not by the authors. In this case the increase in FRC will be greater that what would be expected from the pressure volume curve (D). Moreover PEEP can promote the recruitment of previously collapsed alveoli. The application of positive end-expiratory pressure (PEEP) can increase the FRC (C), usually termed, in the presence of PEEP, the end-expiratory lung volume (EELV). If the mechanical properties of the system change, such as in the case of decreased compliance (dashed line), the FRC will decrease as well (B). The functional residual capacity (FRC) is the volume at which the system is at equilibrium and does not generate any pressure (A). The figure displays the pressure-volume curve of the respiratory system on an arbitrary scale.
For this reason, FRC appears to be a very promising tool for monitoring lung recruitment. In this case, the increase in FRC will be greater than expected, because the system will shift to a different pressure-volume curve ( Fig. The action of PEEP can, moreover, determine the re-opening of previously collapsed alveoli (recruitment). On the other hand, if at end-expiration the airway pressure is kept above the atmospheric one by application of a positive-end expiratory pressure (PEEP), the system will reach a different equilibrium (i.e., FRC) at a higher lung volume, which is usually termed the end-expiratory lung volume (EELV, which corresponds to the FRC in the presence of PEEP, although in this chapter we will use the term FRC for FRC and EELV). Moreover, if a fraction of the alveoli collapse or are flooded (as frequently occurs in the setting of acute lung injury ) this will also result in a decrease in FRC. If the mechanical properties of the system change, FRC will change as well: For example, if lung compliance decreases, elastic recoil pressure will increase, and FRC will decrease so that a new equilibrium with the elastic recoil pressure of the chest wall is reached. In other words, FRC is the volume at which the elastic recoil pressure of the chest wall equals that of the lung and, at FRC, the system is in equilibrium. Functional residual capacity (FRC) is defined, in classical physiology, as the volume of gas remaining in the lungs at the end of expiration.
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