CRC 431 Cardiopulmonary Physiology & Disease Bill Pruitt, MBA, CPFT, RRT, AE-C

CRC 431 – Cardiopulmonary Physiology & Disease Bill Pruitt, MBA, CPFT, RRT, AE-C

 Wilkins Assessment 6th ed Ch 9 (Read first )  Egan Fundamentals 9th ed Ch 19

 White Competencies 5th ed Ch 5  Lecture notes

 Youtube

 “Basic Interpretation of PFT” by PJSMDPETE 1. 19:50 Spirometry

2. 15:12 Volumes and Diffusion

3. 9:26 Pitfalls and abnormalities (??)



Age -



Height-



Sex-

 Race/Ethnicity also influences predicted

values

◦ _{(sometimes called reference values)}

 Reports given with Measured, Predicted , and

Percent predicted. Example:

 FVC Meas = 4.71 Pred = 5.28, % Pred = 89

Value Meas (L) Pred (L)* % Pred

FVC 4.71 5.28 89

FEV₁ 3.05 3.51 87

FEV₁/FVC 65

Note: FEV₁ratio is 65 (abnormal), and the

FEV₁% predicted is 87 (normal)



Weight



Environment (ie. air pollution, altitude)



Smoking

◦ _{See nomograms for males/females on page 92 in}

Before performing spirometry, withhold:

 Short acting β₂-agonists for 6 hours  Long acting β₂-agonists for 12 hours Anticholinergics

 Ipratropium for 6 hours  Tiotropium for 24 hours

Optimally, subjects should avoid caffeine and cigarette smoking for 30 minutes before performing spirometry

At least 3 tests and:

1. Acceptable tests have no hesitation …BEV < 5% of FVC (this is the start of test)

2. Acceptable tests have at least 6 seconds for

exhalation (this is the middle of test) (but don’t stop until…….)

3. Acceptable tests reach a plateau (this is the end of test for recording exhalation )

4. The 2 best tests FVC values + 150 ml 5. The 2 best FEV₁ values + 150 ml

6. The best 2 acceptable tests PEF + 10%

1, 2, 3 are “within” test criteria; 4, 5, 6 are “between” tests

 Feeling light-headed

 Headache

 Getting red in the face

 Fainting: reduced venous return or vasovagal

attack (reflex)

 Transient urinary incontinence

Spirometry should be avoided after

recent heart attack or stroke

 Indication: FEV₁ratio is less than predicted

 Patient should hold meds that could “blunt”

the spirometry

◦ _{Hold quick-acting bronchodilators at least 4 hours prior to}

testing (if possible), long lasting at least 12 hours

 Record baseline (pre) F/V loops and lung

volumes (lung subdivisions) before giving bronchodilator.

 Give tx and wait 15 minutes before retesting

 To be called “Significant response to

bronchodialtor”

◦ _{(+) 12% change and 200 cc increase in FEV1} ◦ _{This is the most “favored” change}

………OR ………

◦ _{(+) 12% change and 200 cc increase in FVC}

 % Change =[ Post - Pre) / Pre] * 100

◦ _{Expectation is for increased FVC and FEV1 post tx}

 Note: Decreased volume (FVC) in post measurements could

 Measures deep and rapid breathing over 12 to 15

seconds

 Rate > 60 (one breath per second)

 Goal is to reach or exceed best FEV₁ x 40 for

indication of patient effort (some use 35)

 Marked reduction reflects higher post-op risks for

 Assumptions

◦ _{N2 in the lungs is assumed to be 78%}

◦ _{Each minute of O2 breathing 30 - 40 ml are washed}

out from blood and tissues

 FRC * N₂% start = Expired volume * N₂% end

Solve for FRC

Nitrogen washout… then

Nitrogen

 Current Method

◦ _{rapid N2 Analyzer with spirometer}

◦ _{breath-by-breath graphic display of %N2 vs}

accumulated volume

 MUST MEASURE N₂ AND ACCUMULATED VOLUME TO GET FRC  Discuss the bath tub illustration

 Technique

◦ _{Test starts with subject at resting end-expiratory level}

(at FRC)… just like the N₂ washout

◦ _{Subject breathes from a spirometer system containing}

~ 10% He (closed circuit)

◦ _{The subject rebreaths air but water and CO2 are}

absorbed and O₂ is added as it is being consumed.

◦ _{Test halted when He % is constant (plateau at + 0.02%}

for 30 seconds); 2 to 5 minutes if healthy, longer if COPD

 Assumptions

◦ _{He does not readily cross the A/C membrane}

◦ _{100 ml is usually subtracted from the determined}

Test halted when He % is constant (plateau at + 0.02% for 30 seconds);

 Helium dilution and Nitrogen washout have certain

errors and problems

◦ _{Leaks make the measurements worthless … stop the}

test

◦ _{Good measurement depends on all parts of lung}

being well ventilated

◦ _{Underestimates FRC in severe obstruction due to poor}

gas communication with the trapped gas (if you don’t measure it, you don’t know its there –eh?)

 Technique

◦ _{Test starts with subject at resting end-expiratory} level (FRC) Shutter closes at zero flow.

◦ _{Subject pants against a closed shutter at rate of 1} Hz.

◦ _{Changes in pressure reflect changes in volume in} the thorax and the box. (Boyle’s Law)

◦ _{Subject holds hands against cheeks to prevent} pressure changes in the mouth due to flaccidity.

 Body Box also gives measurement of resistance and

 Relies on Boyle’s gas law which states that

volume and pressure vary inversely if temperature is held constant.

 V1* P1 = V2 * P2

 V1 = (V2 * P2)/P1

 The pressure measured is a combination:

mouth, box

 The volume measured is from the box, and

 Measures Thoracic Gas Volume (V_TG)

 V_TG may be larger than FRC if there is gas trapped in

the body (pneumothorax, abdominal gas) but this is rare!

 FRC should match V_TG for reliable start of test

(shutter should close at end of exhalation or at FRC)

 More accurate than N₂ washout or Helium

dilution…. Measures all the volume trapped in the lungs

 Measures how quickly gases move across the

alveolar-capillary (a-c) membrane

 Sometimes called “Transfer factor”

 Abbreviation – DLCO_SB referring to “diffusion in the

lung of carbon monoxide in a single breath”

 Interpretation uses DLCO/VA where VA = alveolar

volume (this is measured by tracer gas – usually methane)

 Gas exchange measurement is effected by:

◦ _{diffusion coefficient of the gas used in testing}

◦ _{surface area of the a-c membrane}

◦ _{thickness of the a-c membrane}

◦ _{blood volume in the pulmonary capillaries}

◦ _{distribution of inspired gas}

 Average normal DLCO is 25 ml CO/min/mmHg.  Emphysema destroys alveoli and thus reduces

surface area and distribution of gas = decreased DLCO and DLCO/VA

 Restrictive diseases [ie interstitial diseases (“osis”)]

reduce lung volume and tend to thicken the A/C membrane = decreased DLCO and DLCO/VA

 Blood volume in the capillaries… think “pulmonary

embolism”

 Bronchitis reduces “raw” DLCO but leaves alveoli

intact for gas exchange,so the DLCO/VA will be normal

 Low capillary blood volume (or PE), low

hemoglobin, and increased COHb reduce the

diffusion. (Correcting for low hemoglobin and/or COHb will increase the DLCO)

 Bronchitis doesn’t typically affect alveoli structures

or volumes, so DLCO will be normal unless there is a markedly abnormal V/Q

Top line at the split – methane (CH4) , bottom line carbon monoxide (CO)

◦ _{If possible… measure hemoglobin to get results}

corrected for Hb issues (polycythemia or anemia)

◦ _{Subject takes in a single breath of the gas source}

(CO and tracer gas )

◦ _{Inspired volume should be 90% of best FVC}

◦ _{Holds breath to 9-11 seconds then exhales}

◦ _{Measures CO and tracer gas after first 750 cc}

 What happens with breath hold of 14

seconds?

 What happens with valsalva maneuver?

 What if the patient just smoked a cigarette?

 Normal >80% predicted *

 Mild 65 - 80% predicted

 Moderate 55 - 65% predicted

 Severe 35 - 55% predicted

 Very severe < 35% predicted

 Spirometry – Key is the FEV₁%

◦ _{If FEV1ratio is below predicted}

(or below 70%) = Obstruction

AND Pre and post bronchodilator is indicated

 Note distinction of FEV₁% versus FEV₁% predicted

---

◦ _{Not held in high favor…. Not “diagnostic”}

 FEF_25-75% below predicted - small airways



Lung subdivisions

A. TLC < 80% predicted and all other volumes

reduced proportionally = restriction

A. RV, FRC, and RV/FRC increased = air trapping B. If airtrapping continues and grows, retrosternal

air develops and you move into hyperinflation

 Diffusion (DLCO) results should be examined

with spirometry and lung volumes in mind

 DLCO/V_A used for interpretation (alveolar volume)

A. DLCO/V_A low + obstruction (airtrapping, hyperinflation?) =

emphysema

B. DLCO/V_A low + restriction (all volumes reduced) = fibrosis

C. DLCO/V_A normal + obstruction (airtrapping, hyperinflation?) =

bronchitis

D. DLCO/V_A low + no lung obstruction or restriction = low hemoglobin , decreased blood flow (PE)

 No bronchodilators, antihistamines, coffee,

tea, chocolate (methylxanthines and theobromines)

 Do a complete PFT - must be free of air flow

obstruction (AFO)

 Bland aerosol to start to check for reaction

 Low dose of *methacholine (provacholine)

inhaled.

 Progressively increase if negative. Start at

0.025mg/ml, 0.25 mg, 2.5mg , 10mg, up to 25mg. Positive response is a 20% decrease in FEV₁

 Finish with a bronchodilator - FEV₁ must be

within 5% of baseline to go home

 The absence of airways obstruction does not rule

out asthma.

 (Normal spirometry?)

 A negative response to bronchial provocation does.  A positive response is not totally clear but adds to

the pieces that say “asthma” (COPD, sinusitis may be positive)

 OR – if you have asthma, you have “twitchy” airways

that will react to provocation. No response? no asthma.

 Spirometry – 6 standards

◦ _{Minimum 3 spirograms recorded}

◦ _{2 of the 3 have + 150 ml in FVC and FEV1, +10% in}

PEF

◦ _{Start of test is acceptable (BEV < 5% of FVC)} ◦ _{6 second exhalation}

◦ _{End of test criteria met (plateau)}

 MVV – 2 standards

◦ _{1 breath/second or total rate 60 to 75 breaths/minute} ◦ _{Goal = FEV1 x 40 (or 35 based on textbook)}

 Lung Subdivisions

◦ _{Gas analysis… machine is in good calibration, no}

leaks

◦ _{Gas reaches acceptable level}

 N2 - stop after 7 minutes if not at ~ 1%

 He % is constant (plateau at + 0.02% for 30 seconds)

 Plethysmography

◦ _{Shutter closes to measure VTG at FRC level} ◦ _{Panting at about 60/min (1 Hz)}

◦ _{Two recordings have to be within +10% in all}

 DLCO

◦ _{Inspired volume is > 90% of best FVC}

◦ _{Breath hold time 9 – 11 seconds, no leaks}

◦ _{Discard first 750 ml before analyzing}

◦ _{Tracer gas and CO calibration is good}

◦ _{Two tests needed that are within + 10 % or 3 ml CO}

 Review the demographics

◦ _{Age, height, gender, race, weight}  Check the symptoms

◦ _{Cough (dry?), SOB, wheezing, chest tightness} ◦ _{Any patterns? Seasonal, occupational?}

 When was the last time they had a SABA? LABA? ICS?

 Look over the history and chief complaint ◦ _{Smoker? Pack yrs? Include pipe, cigar, waterpipe} ◦ _{Comorbidities?}

 Ischemic heart disease (CAD), hypertension, CHF, pulmonary hypertension, M.I., stroke

 Lung cancer

 Restrictive lung diseases (asbestosis, sarcoidosis)  Pulmonary embolism

 Pneumonia, CF, bronchiectasis

 DM, obesity, OSA, malnutrition, GERD  Dementia, Alzheimers, depression

 Neuromuscular diseases

 Osteoporosis, arthritis, gout, hearing loss, vision loss

 Read the comments made by the person

coaching the test  “C/O chest pain”

 “Frequent coughing”

 “Unable to perform test, unable to follow instructions”

 Look at the graphs

 Study the numbers and check against the

predicted values

 <80 % predicted or <LLN to define

 History

 The patient is a 73-year-old black woman with a previous

history of COPD. She denies cough or sputum production. She states that any activity results in breathlessness. She has a 50 pack-year smoking history but quit 4 years ago.

 She had repeated bouts of pneumonia as a child, but has no

other occupational or exposure history. She currently takes Advair and uses albuterol as a rescue inhaler. She has not used either medication this morning

 66.5 inches tall, 230 lbs  African-American

Spirometry _Predicted Measured

Pre-tx % Predicted

Measured

Post -tx % Predicted % Change

FVC (L) 2.56 1.73 67 2.04 80 18 FEV₁ (L) 1.98 0.65 33 0.84 42 28 FEV₁/FVC (%) 77 38 41 9 FEF_25%-75% (L/sec) 1.76 0.18 10 0.33 19 81

FEF_max (L/sec)

5.00 2.87 57 2.80 56 -2

MVV (L/min)

87 24 28

Lung volumes _Predicted Measured

Pre-tx % Predicted SVC (L) 2.56 2.25 88 TLCpl (L) 4.38 5.98 136 RVpl (L) 1.82 3.73 205 VTG (L) 2.60 4.40 169 RV/TLC (%) 42 62

Diffusion Pred Actual %Pred DL_CO(ml/min/mm HG) 18.1 8.8 49 DL_COcor (ml/min/mm HG) 18.1 9.3 51 D_L/V_A 4.31 2.79 55 V_A (L) 4.38 3.32 76 Hb 12.21 g/dl

 Good example of a common pattern of

pulmonary pathology associated with COPD.

 PFT shows severe airway obstruction seen

in the FEV₁ and FEV₁ratio.

 Lung volumes show air trapping (increased

RV and RV/TLC ratio) and hyperinflation

(increased TLC). The slow VC is significantly larger than even the post-bronchodilator

FVC.

 These findings are suggestive of

emphysema

 Patient’s response to inhaled bronchodilator

suggests some reversibility of the obstruction (Asthma too?).

 Her DL_CO shows a severe reduction in diffusion

(DLCO/VA) suggestive of emphysema (e.g., loss of alveolar surface area, destruction of capillaries, and increased diffusion distance from the terminal

 40 yr old white male c/o SOB with activities.

 Has had problems from childhood with

wheeze, SOB

 Also snores and makes loud noises during

sleep

 Has been taking DPI flucticasone/salmeterol

(250/50) 1 puff BID and albuterol MDI 2 puffs PRN- did not feel that they did much

 Had a sleep study that was read as negative

but patient stated that he “couldn’t sleep”.

 Being treated for asthma. We saw him at the

 PMH includes obesity, renal stones, deviated

septum, HTN (controlled) He is 6’3” tall and 320 lbs.

 Only hospitalization was in 2000 for a catfish

puncture to his hand.

 Family history: Son has asthma, Mother – DM,

renal stones. Father has hyperlipidemia

 Occcupation: Commercial fisherman

 Married , never smoked, drinks about 3 beers

a month and about 3 glasses of tea or coffee a day.

 1st visit in July with c/o bilateral swelling in

his legs, 30 lb weight gain in 3 months. Some DOE noted. Had some labs drawn

 2nd visit - August F/U with lab work, c/o

lumbar pain – Tx with moist heat and stretching

 3rd visit Oct. c/o dry cough, sinusitis. More

issues with DOE, SOB

 4th visit 2 weeks later in Oct. – nothing

 Referred to Pulmonary clinic in Nov. for his

5th _{visit. Spirometry done with frequent}

errors, hard to get a good quality recording. Odd phonation noted.

FVC- 4.89 L (79% predicted) FEV1- 3.74 L (76% predicted FEV1/FVC – 76% No time to get pre/post… we had class Rescheduled for further testing

 51 yr old female -chief complaint: SOB and cough

 Arrived to the ED with cough, chest congestion, fever,

chills. Prod cough- thick yellow sputum

 PMH includes CHF,COPD, HTN, ASCVD with stents

placed in 2007

 Current medications include carvedilol (Coreg),

Albuterol MDI 2 puffs BID, lovenox (Enoxaparin), HCTZ, lisinopril (Zestril)

 No known allergies

 Social history: Divorced, 2 PPD for 30 yrs (60 pk/yr)

 Family history includes Cancer, COPD

 Vitals: BP 145/92 mm Hg, HR 128 beats/min, Resp.

24 breaths/min, Temp 97.8 F. SpO2 on Room air- 88%

 Physical exam

◦ _{General – pleasant 51 year old female, awake and alert,} mildly dyspneic, occaissional congested cough

◦ _{HEENT: Not remarkable}

◦ _{Neck: trachea midline without JVD}

◦ _{Chest: Bilat BS equal with scattered wheezing and basilar} crackles

◦ _{Heart: Regular S1 and S2. No gallops or murmurs} ◦ _{Abdomen: Soft, nontender, nondistened}

◦ _{Extremities: no cyanosis, some mild clubbing, no edema} ◦ _{Ht 5’3”, Wt 113 lbs}

 CBC:

◦ _{WBC 14.2 (H) 3.8 – 11.0 k/uL} ◦ _{RBC 4.36 3.8 – 5.1 m/uL} ◦ _{Hemoglobin 10.1 (L) 11.0 – 16.0 g/dL} ◦ _{Hematocrit 33.2 34-47%}

 Metabolic panel: Meas. Normal range Units

◦ _{Sodium 131 (L) 135 – 148 mmol/L} ◦ _{Potassium 4.9 3.5 – 5.15 mmol/L} ◦ _{Chloride 94 (L) 96- 112 mmol/L} ◦ _{CO2 27 21-34 mmol/L} ◦ _{Calcium 9.6 8.0 – 11.0 mg/dL} ◦ _{Glucose 132 (H) 74-106 mg/dL} ◦ _{BUN 17 7 – 18 mg/dL} ◦ _{Creatinine 1.10 0.43-1.13 mg/dL} ◦ _{SGOT (AST) 24 15-37 U/L} ◦ _{SGPT (ALT) 31 30-65 U/L} ◦ _{Alk. Phosphatase 100 40 -128 U/L} ◦ _{Bilirubin, Total 0.5 0.2-1.4 mg/dL} ◦ _{Total Protein 7.2 5 – 9 gm/dL} ◦ _{Albumin 3.8 3.5-5.0 g/dL}

Sorry - Post

SABA results are missing

 Spirometry shows Mrs. Jones has very severe

COPD by GOLD guidelines

 Her only pulmonary medication on admission

was albuterol MDI, 2 puffs BID

 GOLD recommends vaccinations, SABA, LABA

(one or more), pulmonary rehabilitation, ICS if repeated exacerbations (at medium dose),

oxygen therapy if in chronic respiratory failure, and consideration for LVRS

 Diagnosis: Stage IV - Very Severe COPD

◦ _{Oxygen at 2 L/min. Keep SpO2 > 90%}

◦ _{Albuterol, 2 mg Q4 w/a and PRN a night}

◦ _{Symbicort, 160/4.5 mcg 2 puffs BID (rinse after)}

◦ _{Ceftriaxone (Rocephin), 2 g IV daily}

◦ _{Prednisone, 80 mg daily for 7 days}

◦ _{Nicotine replacement patch, 21 mg/day}

 Smoking cessation counseling

 Nutritional consult

 Social services to discuss end-of-life issues,

patient assistance program for medications

 At discharge: Set-up home oxygen, nebulizer,

 Consider metered dose inhaler for LABA, ICS

combination (Symbicort, Advair MDI,

Dulera)… her inspiratory flow is likely too low to administer a DPI (cannot access Spiriva,

 Technologist must be well-trained and

should have quality checks performed periodically for competency

 Quality should include calibration checks

daily?

 Abnormal spirometry showing obstruction

should have pre/post SABA assessment made

 Abnormal spirometry often calls for more

testing to evaluate lung volumes and diffusion

 Spirometry provides best diagnostic evidence, clear, objective measurement, basis for tracking changes, guides best practice for treatment

 Spirometry results should not exist in a vacuum – history, symptoms, demographics, current

medications, co-morbidities, technologist

comments on the test, etc. must be included.  To get a correct interpretation and to decide on

treatment – other PFT tests may be needed (in addition to lab, radiologic tests)