Pft 2 Flashcards
Def (FRC) Functional residual capacity
The volume of gas remaining in the lungs at the end of a quiet breath
(End expiratory Level)
(RV) Residual volume def
The volume of gas remaining in the lungs at the end of a maximal expiration regardless of the lung volume at which exhalation was started.
FRC and rv report value
In L Or ml
Phases of single breathe nitrogen washout (SBN2)
- Upper airway gas from the anatomical dead space consisting of 100% 02
- Mixed dead space gas in which the relative concentrations of o2 and N2 change abruptly as the volume is expired
- A plateau caused by the exhalation in alveolar gas in which relative o2 and N2 concentrations change slowly and evenly.
- Abrupt increase in the concentration of N2 that continue until RV is reached
(Engulfed and Bohr) How to estimate dead space-
Individuals body size 1ml/lb ideal bw liters per min
Alveolar minute ventilation
VA= (TV-VD)*F
High altitude simulation test
(HAST)
Mimics high altitude in people with possible hypoxia during air travel (Copd) (pulmonary fibrosis) 8000ft
Open circuit multiple breath nitrogen washout
Washing out N2 while pt breathes 100% n2 at the end is 1% (15 min between)
Calc Tlc
Tlc= RV+ VC or FRC + Ic
Body plethysmography
Is measured by a sensitive transducer calibrated by a gas into a sealed box airway is occluded momentarily at or near FRC pt gently pant allowing air in the chest to be compressed and decompressed.
FRC valve
Using closed circuit multiple breath helium dilation
Dead space
Lung volume that is ventilated but not perfumed by pulmonary capillary flow
Pao2 equation=
Fio2(Pb-47)-(Paco2*1.25
Occlusion pressure (p100)
Is the pressure generated at the month during the first 100msec of an inspiratory effort against an occluded airway
Minute ventilation
Ve=Vt*f
