Formula for calculating Minute Alveolar Ventilation
VA = RR x (Vt-Vds)
MIP is most commonly used to _____?
determine the weanability of mechanically ventilated pateints
Normal MIP
at least -60 cm H2O
Normal MEP
at least 80 cm H2O
Significance of VC
in general, a decreasing VC is a sign the patient is tiring or ventilatory effort is inadequate
Normal adult peak flow
used to access effectiveness of bronchodilators
"Green Zone" Peak Flow
80%-100% of predicted: adequate control
"Yellow Zone" Peak Flow
50-79% of predicted: not adequately controlled
"Red Zone" Peak Flow
less than 50% of predicted: not controlled
Exhaled Nitric Oxide (eNO)
measures eosinophilic airway inflammation
Indications for screening spirometry
R/O airway obstruction; access presence of airway obstruction in an at-risk patient; access the severity of airway obstruction in a symptomatic patient
Critical FEV1/FVC value
70%
If patient's ratio is < 70%, there is an airway obstruction problem
Spirometry findings in patients with restrictive disease?
all volumes and capacities are smaller than predicted
A small FEF25%-75% with a normal FVC may indicate:
early small airway disease
The FEV1 is most commonly used to ____?
judge patient's response to inhaled bd
FVC in restrictive lung disease
exhale the FVC more quickly than expected
FVC in obstructive lung disease
take longer than expected to exhale the FVC
Which is the most important forced expiratory volume test?
Ina flow-volume loop, what sign is characteristic of restrictive disease?
small volumes with right shift.
In a flow volume loop, what does a near normal FVC volume and a greatly decreased peak expiratory flow rate suggest?
variable obstruction from tumor or FB
In a flow-volume loop, what does a near normal FVC volume and a greatly reduced inspiratory flow rate suggest?
variable extrathoracic obstruction such as vocal cord paralysis, laryngeal tumor or FB
In a flow volume loop, what does a near normal FVC volume with reduced inspiratory and expiratory flows suggest?
a fixed obstruction such as a tumor in the trachea or mainstem bronchus
What does the Nitrogen Washout Distribution Test (also called the Single-Breath Nitrogen Washout Test) measure?
evenness of the distribution of ventilation into the lungs during inspiration and the emptying rate of lungs during exhalation.
What does the Helium Dilution Test measure?
FRC
General Rule: TLC > 120% predicted indicates?
obstructive disease
General Rule: TLC <80% of predicted indicates?
restrictive disease
Indications for a lung compliance test?
Distinguish between overly compliant lungs (emphysema) and noncompliant lungs (fibrosis).
DLCO measures:
diffusing capacity of carbon monoxide to diffuse through the lungs into the blood. Indicated in emphysema and fibrosis.
RV, FEC & TLC > 120% predicted indicates?
Obstructive disease with air-trapping
EV, FRC & TLC <80% predicted indicates?
restrictive lung disease
Which of the following statements is true of the MEP test?
B) a pressure of +40 cm H2O usually is adequate and it is a good indicator of the patient's ability to cough & the patient should hold the effort for 1 to 3 seconds
The predicted FVC value for African-Americans is:
A) 10% to 15% less than for Caucasians
Which of the following test results are needed to calculate TLC?
A) RV & VC only
A normal MEFV loop would show:
D) FEF50% less than FIF50%
A person with neuromuscular disease has been having serial bedside spirometry performed. Over the past 4 hours, her VC and MIP values have been decreasing. How should this be interpreted?
C) her condition is worsening
An order is received to perform the following bedside spirometry tests on a patient: Vt, FVC and peak flow. Which device would you take with you to perform the tests?
A) differential pressure pneumotachometer
Before a patient does an FVC test, the pneumotachometer should have the following done:
C) a 3L volume should be pumped into and out of the circuit
For help in the diagnosis of a patient with a questionable hx of wheezing and possible asthma, which of the following would be the best test?
C) bronchoprovocation test
A patient has just been tested for CL in a body plethysmograph. The patient's compliance was determined to be 0.2 L (200 ml)/cm H2O. Based on this data, the patient most likely has:
B) emphysema
Calculate a patient's inspiratory and expiratory times when he has an I:E Ratio of 2:1 and a RR of 15 bpm.
B) 2.7 seconds for inspiration and 1.3 seconds for expiration
When a patient performs an MEP test, it is important that he or she:
A) inhales to TLC and blows out hard
A patient weights 45 kg (100 lbs). The patient's predicted Vt would be:
B) 350 ml
An order is received to calculate a patient's alveolar ventilation. The patient's RR is 16 and average Vt is 580 ml. The patient weighs 170 lbs. The patient's alveolar ventilation is:
C) 410 ml
A patient has an FEV1 that is calculated to be 80% of her/her FVC. On the basis of this finding, the patient probably:
D) is clinically normal
The VC is made up of the:
C) ERV, Vt and IRV
Which of the following are true of PF measurement?
A) it increases with height and decreases with age and is usually seen at the beginning of the patient's FVC effort
An RT is having a patient perform the MIP test. His three attempts produce these results: =15 cm H2O, -45 cm H2O and -20 cm H2O. The best explanation for these values is that:
A) the patient is not trying his best every time
The physician wants to know whether a new bronchodilator would be helpful to the patient with asthma. The physician orders a new before and after BD study. The patient has the following peak flow values: 7.5 lpm before the medication and 9.4 lpm after the medication. Calculate the percentage change.
C) 25%
Complete spirometry is performed on a 50 YO patient, revealing the following data: TLC 137% predicted; RV 164% predicted; FVC 52% predicted; FEF25-75 36% predicted; and FEV1/FVC 27% predicted. How should this data be interpreted?
B) severe obstructive disease
A nitrogen washout test for RV has been performed on a patient for 7 minutes and has not reached the desired nitrogen percentage. What could explain this situation?
D) the patient has severe air trapping
A new patient has been scheduled for a battery of PFT's. He tells you that he is so nervous about the testing that he has smoked 4 cigarettes in the past two hours. Which of the following tests is most likely to be affected by this?
C) lung diffusion
After spirometry is performed, it is important that the patient flow rates be reported at:
B) BTPS
A patient is performing a residual volume test on a water seal spirometer in the PF Lab. After breathing on the system for 1 minute, the patient takes out the mouthpiece and c/o being SOB. What is the most likely problem with the PF system?
C) the CO2 absorber has been left out of the system
Which of the following studies produces the most accurate determination of the TLC in a patient with severe emphysema?
B) body plethysmograph test
The PF Lab has recently acquired an exhaled nitric oxide analyzer. Which patient population should it be used with?
A) asthmatics
Before a patient performs a FVC test, all of the following should be done to the water sealed spirometer EXCEPT:
C) place CO2 absorbing material in line with the circuit
A properly performed FVC test will not have:
B) any coughing or leaks or weak patient effort or an unsatisfactory start or exhibit excessive variability among the test results
A patient has the suspected diagnosis of asthma. Which of the following tests would be the LEAST helpful in assessing the patient for this condition?
A) diffusion study
A patient with COPD has been admitted. To help clarify the patient's diagnosis as emphysema or asthma, which of the following should be recommended?
C) spirometry before and after an inhaled beta agonist
As teh therapist in the PF Lab, you have received an order to perform exhaled NO analysis, spirometry and RV testing on a 10 YO girl with a hx of wheezing and chronic cough. First, you perform eNO analysis and find the girl's eNO value to be 35 ppb. How should this information be interpreted?
D) the patient's value is increased from normal
A wright respirometer can be used for all of the following bedside spirometry tests EXCEPT:
