Facilitator Version
Module #7, COPD
Created by Seth Scott, 2/14
Objectives:
1. Be able to list criteria for a COPD exacerbation.
2. List 3 differential diagnoses for shortness of breath.
3. Be able to correctly interpret an arterial blood gas.
References:
Sources/Further Reading:
1. Criner, Gerard, Barnette, Roger, D’Alonzo, Gilber. Critical Care Study Guide: Text and
Review. Springer Books 2nd Ed 2010
2. Hannaman, R, Walkey, C. Med Study Internam Medicine Review Core Curriculum 15ht
Edition. Med Study 2013 Book 2. pp 3-17 to 3-22
3. MKSAP 16
4. Leuppi, JD, et Al. Short-term vs conventional glucocorticoid therapy in acute
exacerbations of chronic obstructive pulmonary disease: the REDUCE randomized
clinical trial. JAMA June 5 2013 pp 2223-31.
5. Vollenweider, DJ et Al. Antibiotics for exacerbations of Chronic Obstructive Pulmonary
Disease. Cochrane Database Syst Review. Dec 12, 2012.
6. Ceviker, Y, Sayiner A. Comparison of two systemic regimens for the treatment of COPD
exacerbations. Pulm Pharmacol Therpay. March 2013.
7. Vestbo J et Al. Global strategy for diagnosis management, and prevention of chronic
obstructive pulmonary disease: GOLD executive Summary. American Journal of
Respiratory and Critical Care Medicine. Feb 15 2013 pp 347-365
8. Littner, MR. In the clinic, Chronic Obstructive Pulmonary Disease. Annals of Internnal
Medicine. April 2011, 154 (7).
9. Goldman, L, Schaffer, A. Goldman’s Cecil Medicine. 24th Edition, Chapter 104 pp.629638. 2012.
Case:
A 67 year old male veteran presents with a 1 week history of gradually progressive shortness of
breath, cough productive of purulent sputum and a 37 pack year history of smoking. Patient
denies PND, orthopnea, and chest pain. He reports that his activity is severely limited in the last
several days with difficulty walking from his bedroom to the living room and bathroom. He had
an upper respiratory infection with rhinorrhea, cough, sore throat and fevers starting about 5
days ago.
What is your differential diagnosis and what are some historical factors suggestive of the
most likely diagnosis?
In this older patient with cough productive of purulent sputum and shortness of breath: COPD
exacerbation, pneumonia, heart failure, lung cancer, and asthma would be on the differential
for certain. Rare diseases with some similar features include occupational lung diseases,
pulmonary hypertension, cystic fibrosis and bronchiectasis.
A recent ACP review on the topic of COPD included a classification system used to evaluate the
severity of exacerbations to look at treatment effects. It included 3 major and 5 minor criteria.
If the patient has1 major + 1 minor is considered a mild exacerbation, 2 major criteria is
moderate, and all 3 major criteria are considered severe 8.
Major:
Worsening of baseline dyspnea
Increase in sputum purulence
Increase in sputum volume
Minor:
Upper respiratory infection in last 5 days
Fever of no apparent cause
Increase in wheezing or cough
Increase in respiratory or heart rate 20% above baseline
What are you looking for in a patient with suspected COPD in the social and family history?
In young patients with symptoms suggestive of COPD consider asking about family history of
young onset similar disease as this may be suggestive of alpha-1 antitrypsin deficiency. This is a
treatable disease and affects the relatively young and is therefore important not to miss.
Social history should be directed at getting a good tobacco history this is best assessed by
getting the patient’s pack year history which is number of packs of cigarettes smoked per day x
number of years they have smoked. Other things to consider are occupational exposures like
asbestos, beryllium, animal dust/mold, and silica dust.
What are things you might want to look for on exam that suggest a severe exacerbation or an
alternative diagnosis?
Typical/frequent physical exam findings in COPD: wheezing, hyper-resonance, prolonged
expiration.
Alarming physical exam findings during an exacerbation: cyanosis very elevated respiratory
rate, distant/absent breath sounds, altered mentation, and accessory muscle use.
Signs typical of an alternative diagnosis: evidence of a focal disease such as egophany, rhonchi,
dullness to percussion, crackles suggesting heart failure or focal consolidation.
Patient’s physical exam:
Vitals: T: 37.2 P: 112 R: 24 BP:135/76 Sats:87% on room air
Gen: mild respiratory distress, thin appearance, AOx4
HEENT: slightly dry mm
CV: regular tachycardic normal s1s2 no m/r/g no elevated jvd or extremity edema
Pulm: diffuse inspiratory and expiratory wheezing with diminished breath sounds throughout.
Notably tachypneic
Abd: bowel sounds present, soft, non-tender, non-distended
What are some tests you should consider getting in this patient to further characterize his
likely COPD exacerbation? What do you expect to see? What should you consider when
thinking about admitting a patient to the hospital with a COPD exacerbation?
Testing should be directed at narrowing the differential diagnosis therefore a chest x-ray and
ECG should be obtained to evaluate for other diagnoses including pneumonia, lung cancer,
pulmonary fibrosis, or heart failure. Patients like this may need evaluation for pulmonary
embolism as this is a frequently missed diagnosis in patients with COPD your decision to do
imaging should be based on their Wells score. The other important thing especially if the
patient looks like they are struggling is to assess the severity of the exacerbation. The preferred
test would be an arterial blood gas (ABG).
Things that should make you think the patient needs to be admitted: Marked increase in
intensity of symptoms especially dyspnea at rest, severe underlying disease in the setting of
acute exacerbation, new physical exam findings including cyanosis or edema, Frequent
exacerbations, new arrhythmias, older patients, insufficient home support7.
Our Patient’s Results:
CXR: hyper inflated lungs, flattened diaphragms, bullae in apices, no focal opacities or effusions
and heart borders narrow and elongated.
ECG: low voltage, sinus tachycardia, no st segment changes.
ABG- pH 7.35 PCO2: 44 PaO2: 62
CBC- WBC: 11 Hb: 17 HCT: 57. Plt: 230
Chem 7- Na: 140 K: 3.9 HCO3: 32 Cl:100 BUN: 12 Cr :0.74
Troponin: 0.001 BNP: 100
Is the patient hypoxic? Are they hypoventilating? What is the A-a Gradient? How do you
calculate it? How do you adjust it if the patient is on oxygen? What does this mean?
The patient is hypoxic as he requires oxygen in order to have normal oxygen saturation.
The patient is not hypoventilating because his pCO2 is in the normal range. To calculate the A-a
gradient see appendix 1 (attached). This patients A-a gradient is 120.
This is an abnormally increased A-a gradient that responds to oxygen therapy. An abnormal A-a
gradient in a patient that responds to oxygen is likely due to V/Q mismatch the differential
diagnosis would include airway obstruction (i.e copd exacerbation/asthma) or thromboembolic
disease. If the patient had very high oxygen requirement then airway filling diseases like heart
failure, pneumonia, or intracardiac shunt would be the likely diagnosis.
What are your next steps? Why?
Albuterol and ipratroprium scheduled and prn for bronchodilation and to decrease work of
breathing.
Prednisone 40 mg day orally. A recent large meta-analysis showed no significant benefit for
using iv over po steroids and that duration of 5 days may be adequate. 5
Antibiotics: a Cochrane review of the use of antibiotics for acute exacerbation of COPD suggests
a significant benefit. 6
The patient’s nurse calls you 2 hours later because the patient is breathing very hard and is a
little bit somnolent despite the measures you have already taken. When you arrive patient
does seem a little sleepy but is arousable and follows commands. He is still oriented and
following commands but is having marked increase in his work of breathing with intercostal
retractions, belly breathing and nasal flaring. On exam his breath sounds are barely audible
and has reduced wheezing from your prior exam. In order to sat adequately he is on 5 L by
nasal cannula. His vitals are T: 36.8 P: 120 R 28 BP: 110/70. What are your next tests?
Deterioration in the respiratory status of a patient should prompt an evaluation of their ABG
and a face to face evaluation. Sudden worsening may prompt you to consider repeating CXR at
a minimum. Physical exam findings suggestive of profound respiratory distress are indications
for non-invasive ventilation.
This patient’s repeat ABG: pH 7.27 PCO2:53 PaO2: 62. Is the patient hypoxic? Is he
hypoventilating? What is the A-a gradient (i.e does hypoventilation explain the hypoxemia)?
How is he responding to oxygen therapy?
What else is concerning about this blood gas and what would you do about it? Why?
The patient is hypoxic as he has increased oxygen requirement.
This patient is hypercarbic and therefore is hypoventilating.
His A-a gradient is 139 (see appendix for calculations).
This still is suggestive of a COPD exacerbation because he is having a relatively good response to
oxygen therapy. 4
Perhaps more importantly in terms of management the patient has developed a respiratory
acidosis as demonstrated by an increased PCO2 and a decreased pH. You may need to consider
NIPPV (non-invasive positive pressure ventilation) as it will improve the respiratory acidosis and
has been shown to decrease the need for intubation, mortality, subjective breathlessness, and
length of hospitalization. The indications for non-invasive and invasive ventilation are in
appendix 1.
The patient does well and after 24 hours of bipap it is discontinued as his gas and respiratory
failure improve. He is back to being on 2 L of oxygen and sats are being maintained at
between 88-90% on this. Without oxygen it drops to 84% at rest. What kinds of follow up
testing does he need and what intervention(s) should he be on to prevent mortality and/or
improve symptoms? How long should acute treatment be for?
1) The patient should have spirometry. There are 2 key results to follow up in order to
classify the severity of his disease: FEV1 and FEV1/FVC ratio. By the GOLD criteria to
make the diagnosis you must have FEV1/FVC ratio of <0.7. Once this is in place then
patients are classified as follows7:
Class
GOLD 1=Mild
GOLD2=Moderate
GOLD 3=Severe
GOLD 4=Very Severe
Criteria
FEV1 >80% predicted
FEV1 < 80% predicted but > 50%
predicted
FEV1 < 50% predicted but > 30%
predicted
FEV1 <30 % predicted
Outpatient management is determined by GOLD score, frequency of exacerbations
and/or hospitalizations, and symptom severity scores (the two scoring systems
recommended by guidelines are MRC (cutoff <2) and CAT (cuttoff<10). GOLD 1-2
patients who score low on symptom scores like MRC or CAT and only 1-0 exacerbations
per year should be given short acting anticolinergics or beta agonists as initial
management. GOLD 1-2 patients who have high symptom scores should get long acting
anticolinergics (tiotropium) or beta agonists (i.e salmeterol) in addition if they have less
than 2 exacerbations per year.
Gold 3-4 patients who have low symptom scores on MRC or CAT should be given beta
agonist + inhaled corticosteroids or long acting anticholinergic as initial management.
PDE 4 inhibitors and/or short acting agents can be added. Patients who are hospitalized
or who have two or more exacerbations per year and have low symptom scores should
have the same management as GOLD 3-4 patients and low symptoms.
Patients who have GOLD 3-4 and high symptom scores should get long acting
anticholineric +/- beta agonist with steroid +/- pde 4 inhibitor. Short acting beta
agonists/anticholinergics can be added.
Simultaneous short acting and long acting anticholinergic meds should not be used.
Patients who are hospitalized or who have two or more exacerbations per year and
have high symptom scores should have the same management of COPD as GOLD 3-4
patients with high symptoms. Inhaled corticosteroids in COPD has been found to have
an associated increased risk of pneumonia but is sometimes used anyway.
2) This patient needs an assessment of his oxygenation, for which a simple oxygen
saturation measured with a pulse oximeter is usually adequate. Long term oxygen
therapy has proven mortality benefit in patients with COPD. Criteria for starting
continuous O2 in COPD patients are as follows7:
-Resting PaO2 < 55
-O2 Sat < 88%
- PaO2 55-60 mmHg or O2= 88% + evidence of pulmonary hypertension, edema from
right heart failure, or Hct>55%. Repeat evaluation should occur at 2 months once on
stable medical regimen as many can have oxygen discontinued once on medications.
3) Pulmonary Rehab- results in improved symptoms, quality of life, survival and
hospitalizations2.
4) Total of 5 days steroids and antibiotics4
5) Influenza, pneumococcal, pertussis vaccination 2
MKSAP 16 Questions: critical care/pulmonary questions
Question 1 – Diagnose COPD, answer B
Question 2 – Manage weaning from invasive ventilation – Answer D
Question 13 – Manage moderate COPD – Answer D
Question 32 – Manage acute COPD exacerbation – Answer B
Question 42 – Diagnose PE – answer B
Question 61 – Manage COPD exacerbation with noninvasive ventilation – Answer D
Question 75 – Manage severe COPD in tobacco user – Answer E
Question 85 – Treat severe COPD – Answer D
Appendix 1:
The indications for non-invasive and invasive ventilation:
Non Invasive
Invasive
pH< 7.35 or PaCO2 >45
Unable to tolerate non-invasive ventilation
Severe dyspnea with signs of respiratory
Failure of non-invasive ventilation
muscle fatigue, increased work of breathing or Decreased loc or agitation not controlled by
both including accessory muscle use,
sedatives
intercostals retractions or paradoxical
Massive aspiration
abdominal motion
Persistent inability to clear respiratory
secretions
Hr<50 with loss of alertness
Hemodynamic instability despite
fluids/pressors
Ventricular arrhythmias
Device and flow rate1
Nasal Cannula
1 LPM
2 LPM
3 LPM
4 LPM
5-6 LPM
Face Mask
5-6 LPM
6-10 LPM
Non Rebreather Mask/High Flow Nasal Canula
15 LPM
FIO2
Nasal Cannula
0.21-0.24
0.27-0.34
0.32-0.44
Face Mask
0.3-0.45
0.35-0.55
Non rebreather:
>80%
0.23-0.28
0.31-0.38
First A-a gradient calculation:
A-a gradient is calculated by the following equation: D A-a= PAO2- PaO2 Where PAO2 = ((Pb –
PH2O)x fiO2)-( PaCO2/0.8) and PaO2= blood gas PaO2 reading. This can be simplified – In
Albuquerque Pb ~630 mmhg and PaCO2 = measurement from ABG.
PAO2 thus for ABQ is ((630 – 47) x fio2) –1.25 (PaCO2) which for room air is 122-1.25(PaCO2)
PAO2 for sea level/ boards = ((760-47) x fio2) – 1.25(PaCO) or for room air 150- 1.25(PaCO)
Therefore for this patient the gradient = ((582)x30% fio2)- 1.25-44 = 176-155=120 mmg/Hg.
Second A-a gradient calculation:
D A-a= PAO2- PaO2
Where PAO2 = ((Pb – PH2O)x fiO2)-( PaCO2/0.8)
This can be simplified – In Albuquerque Pb ~630 mmhg and PaCO2 = measurement from ABG
PAO2 thus for ABQ is ((630 – 47) x fio2) –1.25 (PaCO2) which for room air is 122-1.25(PaCO2
PAO2 for sea level/ boards = ((713) x fio2) – 1.25(PaCO) or for room air 150- 1.25(PaCO)
For this patient FiO2~70-80% therefore PAO2 = (630-47)x.35 . -1.25x52= mmHg
His gradient is 204-65=139 mmgHg.
Post Module Evaluation
Please place completed evaluation in an interdepartmental mail envelope and address to Dr.
Wendy Gerstein, Department of Medicine, VAMC (111) or give to Dr. Patrick Rendon at UNM
Hospital.
1) Topic of module:__________________________
2) On a scale of 1-5, how effective was this module for learning this topic? _________
(1= not effective at all, 5 = extremely effective)
3) Were there any obvious errors, confusing data, or omissions? Please list/comment below:
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________
4) Was the attending involved in the teaching of this module? Yes/no (please circle).
5) Please provide any further comments/feedback about this module, or the inpatient curriculum
in general:
6) Please circle one:
Attending
Resident (R2/R3)
Intern
Medical student