in a healthy individual, so the anatomic dead space is less than the physiologic dead space?

Some clinicians use AVDSF at the bedside to monitor changes in dead space.

Using the P ETCO 2, the end-tidal alveolar dead-space fraction (AVDSF) can be calculated (AVDSF = /P aCO 2). On the other hand time-based capnography is routinely used for mechanically ventilated children, reporting the end-tidal P CO 2 (P ETCO 2) with each breath. However volumetric capnography requires specialized equipment not used for most mechanically ventilated children. Although it has limitations, volumetric capnography is generally considered an accurate method to evaluate dead space. The mean expiratory P CO 2 and breath-by-breath curve analysis obtained from volumetric capnography, in conjunction with P aCO 2 level, provide the data needed to estimate physiologic, airway, and alveolar V D. Volumetric capnography measures the volume of CO 2 exhaled with each breath. Hence, measuring alveolar dead space provides information on the severity of lung disease and adequacy of pulmonary perfusion, both globally and regionally. 12 However, in critical illness, decreased alveolar perfusion can lead to large alveolar dead space due to alveolar overdistention, decreased cardiac output, or a multitude of other causes. Alveolar dead space (alveoli receiving ventilation without perfusion) is close to zero in healthy children. 11 Airway dead space represents regions of the respiratory system that receive V T but do not normally participate in gas exchange (eg, large conducting airways and the endotracheal tube for intubated children). In healthy children, the physiologic dead-space-to-tidal-volume ratio (V D/V T) ranges from 0.3 to 0.35. Physiologic dead space is composed of both airway dead space and alveolar dead space. 1– 8 Optimizing mechanical ventilation settings by minimizing dead space has the potential to improve outcomes in children with respiratory failure.

Large dead space in mechanically ventilated children and adults is an indicator of respiratory disease severity and is associated with increased mortality, longer duration of mechanical ventilation, and higher extubation failure rates. Monitoring dead space in critically ill children is useful for both prognostic and therapeutic reasons.

In a healthy individual, so the anatomic dead space is less than the physiologic dead space?