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### WilliamWall Adv DX chapt 8 PFT

How many lung volumes are there 4
how many lung capacities are there 4
what are lung volumes distinc measurements that do not overlap each other
what are lung capacities measurements containing two or more lung volumes
what volumes and capacities cannot be measured directly RV, FRC and TLC
how do we measure RV, FRC and TLC indirectly using helium dilution, nitrogen washout, body plethysmograph or radiologic estimation
Calculating TLC IRV+VT+ERV+RV or VC+RV or IC+FRC
Calculating VC IRV+VT+ERV or IC+ERV or TLC-RV
Calculating IC IRV+VT or TLC-FRC or VC-ERV
Calculating FRC ERV+RV or TLC-IC
TLC total lung capacity, sum of VC and RV, based on age size and gender, increased w/obstructive and decreased with restrictive
VC vital capacity, max exhaled volume after a deep breath (if forced it is called FVC)
what is the most important part of the FVC coaching, bad coaching is bad results
the 3 phases of the FRC are max inspiratory effort, initial expiratory blast, forceful emptying of the lungs
why do we not continue coaching and yelling during the forceful emptying portion of the FRC may lead to airtrapping in obstructive pts
can a VC be to high? no, the higher the better, just to low
how does obstructive disease cause a decrease in FRC by causing a slow rise in the RV
IC inspiratory capacity, measured with spirometer
FRC functional residual capacity, (RV+ERV is FRC) resting volume in lungs following exhalation of VT
what volume represents the the force of the expanding chest wall and the contractile rebound of the lung tissue(elastic equilibrium) FRC
what kinds of diseases cause a <FRC pneumothorax, restrictive diseases, age, obesity
what kinds of diseases cause an >FRC emphysema, any disease that causes a loss of lung tissue, obstruction
IRV inspiratory reserve volume, measured with routine spirometer
VT tidal volume, exhaled or inhaled in each breath, can be reduced in both restrictive or obstr
a decrease in VT with no change in RR will result in what hypoventilation and >CO2
What is the normal RR for a pt with restrictive disease increased, because VT's are shallow, RR must be increased to proportional to loss of VT
SVC slow vital capacity, test performed by having pt blow everything out slowly after max inspiration, allows for less airtrapping
what is the most important measurement for a preop pt VC, significant reduction in VC indicates pt is at high risk for resp failure after surgery
ERV expiratory reserve volume, (FRC-RV is ERV) max exhaled following passive exhalation, < obesity, poor performance and restrictive (limited clinical use)
RV residual volume, amount left in lung after pt exhales all that is physically possible, < in restrictive and >in obstructive as airtrapping occurs
RV/TLC, what percent of TLC is normally RV 25%
RV/VC, what percent of VC is normally RV 33%, >33% COPD is present
What is the significance of a reduced RV/VC none, there are no clinical states that reduce RV/VC only increase as with COPD (will be in normal range with restrictive disease state)
VE RRxVT, best index of ventilation when used in conjunction with ABG. Should be up with exercise, fever, pain, hypoxia and acidosis
What does the expiratory side of the FVC curve provide contractile state of the airways, FEV1, FEV3, FEF25-75, PEF (peak flow)
FEVt forced expiratory volume timed in liters (t is commonly expressed in .5, 1, 2, 3 seconds) norm is relative to his FVC
FEV1 max forced exhalation during 1st second, best indicator of obstructive disease, reflects the flow in larger airways, best express as a % of FVC (FEV1/FVC is FEV1%), norm is 75% of VC, <in acute or chronic COPD, norm in restrictive
FEV3 looks at the 3 second point on the curve.
FEV.5 and FEV1 used along with FEV200-1200 to assess the flow rates and disorders of the large airways, will be < with airway obstruction
FEV% FEVT/FVC reduced with obstructive disorders
FEV1% 75-85% <65% is is airway obstruction
FEV3% 95%
FEF25-75% sensitivity test expressed in L/sec (measures flow or speed of exhalation), middle 50% of the exhalation (not 50% point but total 50%) and reflects patency of airways, best early indicator of obstructive disease
PEF max flow rate during PFT maneuver, steepest part of FVC, can be measured with spirogram or hand-held device at home or ER. Often used by asthmatics to measure severity of asthma obstruction
PEF measurements <100 L/min is sever obstruction, 100-200 L/min is mod to severe obstruction, >200 is mild
Once treatment has been started in an asthma pt, what test can be given to help determine response to TX PEF
spirometer positive displacement-volume, used to measure volumes and flow rates
water-seal spirometer measures volume and time
what is the best indicator of a restrictive disease? Vital Capacity
how do we measure obstructive diseases flow rates, FEV1, FEF200-1200, FEF25-75, PERF and FVC
what is the best indicator of obstructive disease FEV1
what is the best indicator of large airway obstruction FEF200-1200
what is the best indicator of a small airway obstruction FEF 25-75
what is the best indicator of airtrapping FVC that is smaller than SVC
what is a PFT determines the functional status of the lungs
what can PFT's be used for presence of pulm disease, esp which pts will be harmed by smoking, evaluating pts before surgery, eval effectiveness of therapy, documenting progression of pulm disease, effects of exercise on lung function, measures degree of airway hyper-responsiveness
what is bronchoprovocation testing PFT that measures degree of airway hyper-responsiveness
contraindications of PFT's recent ab, thoracic or eye surgery, hemodynamic instability, symptoms indication acute sever illness, recent hypoptysis, pneumothorax, recent hx of ab thoracic or cerebral aneurysm
what tis the most important factor influencing lung size and predicted values height
at what age does a persons lung size begin to shrink 20yrs
what is the primary instrument used in PFT's spirometer
what does a spirometer measure the lung volume compartments that exchange gas with the atmosphere
spirograph attaches to spirometer to graphically record PFT's
spirogram the graphic tracing of the PFT
body plethysmograph for total lung capacity and airway resistance studies
what are the 2 main categories of PFT abnormalities obstructive and restrictive defects
how do obstructive disease present on PFT's if expiratory flow is below normal
how do restrictive diseases present on PFT's if lung volume is reduced
Upper airway obstruction will show up where on PFT reduced flow rate in initial 25% of FEC
what portion of the flow/volume curve is effort Dependant the first 1/3
what portion of the flow/volume curve is effort independent the later 2/3
a restrictive disease is present when PFT lung volumes are reduced to less than 80% of predicted levels
what are the two most common causes of restrictive disease atelectasis and obesity
what are two examples of combined obstructive/restrictive disease sarcoidosis and emphysema
sarcoidosis unknown cause characterized by deposition of cicronodules called noncaseating granulomas throughout the body and lungs
what is the easiest way to distinguish between obstructive and restrictive diseases on a PFT obstructive causes reduced expiratory flows, restrictive causes reduced lung volumes
3 ways to measure TLC body plethysmograph (body box), open-circuit nitrogen washout, or closed-circuit helium dilution
why is body box more accurate it measures communicating and non-communicating/poor communicating spaces (volumes)
what are non communicating or poor communicating lung volumes airtrapping (COPD, Asthma) or pneumothorax
(open-circuit) nitrogen washout air in lungs is 79% nitrogen just like atmosphere, pt breaths 100% O2 for approx 7 mins, nitrogen is measured during exhalation for volume measurements
(closed-circuit) helium dilution pt breaths helium for 7 minutes, when equilibrium is reached, helium is measured and lung volumes are calculated
why is helium used as a measuring gas helium is an inert gas so not significantly absorbed
what PFT equipment uses an open-circuit system nitrogen washout
what PFT equipment uses a closed-circuit system helium dilution
what is the most accurate determination of gas volumes in the chest plethsmograph/body box
MVV, max voluntary vent rapid & full as possible for 12-15 seconds, total exhaled is obtained,repeat 4 or 5 times and multiplied to get a max volume for 1 minute (15x4 is 60), measures status of resp muscles, compliance and resistance, used prior to surgery, not generally useful
Flow volume loops (FLOOP) flow and volume on a graph paper, V is horizontal, F is vertical, Inspiration is below horizontal, expiratory is above
how are FLOOPs used to show if response to medications two flow volume curves superimposed on each other, one before bronchodilator and one after
FLOOPs are best used to look for patterns in what diseases restrictive (<volume), large airway obstruction (<flow, norm volume), severe COPD (hockey stick or boot)
PFT's before and after bronchodilator 2 of 3 must improve, FVC >10%, FEV1 15%, or FEV25-75 20-30%, best in asthmatics, misleading in COPD
DLCO diffusion capacity of the lungs, <with emphysema and pulm fibrosis
RAW normal w/out ETT tube .5-3.0 cmH2O/L/sec, as airways narrow, pressure of resistance increases
compliance volume change per unit of pressure change, measured with balloon catheter
Dynamic compliance measured when gas is flowing
static compliance measured with no flow of gas
Total CL lung tissue compliance + chest wall compliance, <CL as lungs become stiff, the more non-compliant the more stiff,
what is a flat top of the curve represent on a floop stiff lungs-<CL, (less volume, more pressure)
what does a round top of the curve represent on the floop emphysema, <elastance (more volume and less press)
RQ respiratory quotient, norm is .8-.85, ratio of CO2 produced to O2 consumed. Fatty diet RQ is .7 and RQ is 1 for carbs, best used during weaning to adjust pt diet and <WOB
Bronchoprovocation pt inhales histamine or methacholine, cold air and exercise, used to test pt for hyperactive airways
methacholine challenge parasympathomimetic used to induce bronchospasm
most useful PFT tests as seen in table 8-1 1-VC, 2-FEV1 and FEV1%, 3-TLC, FRC, RV, RR, VE, FEV3, FEV25-75, DLCO, RAW and CL
Do PFT's measure the ability of the lungs to exchange resp gases no, DLCO does and it is done in a closed circuit helium test with carbon monoxide
which of the following is least use PFT-A)documenting disease progression B) eval probability of getting a pulm disease C) exercise eval D) weaning from mech ventilation B is
The tracing obtained from a PFT is called spirogram
which is the most important factor in predicting PFT measurement age, weight, height, gender height
PFT's are effort dependent T/F True
What piece of equip is used to measure TLC and RAW body plethysmography
which of the following are consistent with obstructive disease? > exp flows, <exp flows, <vol and flows, or >volumes and flows <exp flow
an obstruction in the upper airway will affect which portion of the spirometric tracing all of it, the initial the middle and the end, it is flat
which is true regarding restrictive disease-<volumes on PFT, can be caused by obesity, exp flow are usually normal all (not sure on the flow)
VT can be > or < with restrictive or obstructive disease VT is < with both restrictive and obstructive
what PFT is useful in determining the need for mech ventilation FVC
Created by: williamwallace