Facilitator Version

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. PulmPharmacolTherpay. 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.629-638. 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. HHe had an upper respiratory infection withrhinorrhea, 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 severe8.

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.ecopd 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 / Criteria
GOLD 1=Mild / FEV180% predicted
GOLD2=Moderate / FEV1 < 80% predicted but 50% predicted
GOLD 3=Severe / FEV1 < 50% predicted but 30% predicted
GOLD 4=Very Severe / 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.esalmeterol) 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 vaccination2

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
Severe dyspnea with signs of respiratory muscle fatigue, increased work of breathing or both including accessory muscle use, intercostals retractions or paradoxical abdominal motion / Unable to tolerate non-invasive ventilation
Failure of non-invasive ventilation
Decreased loc or agitation not controlled by sedatives
Massive aspiration
Persistent inability to clear respiratory secretions
Hr<50 with loss of alertness
Hemodynamic instability despite fluids/pressors
Ventricular arrhythmias
Device and flow rate1 / FIO2
Nasal Cannula
1 LPM 2 LPM
3 LPM 4 LPM
5-6 LPM / Nasal Cannula
0.21-0.24 0.23-0.28
0.27-0.34 0.31-0.38
0.32-0.44
Face Mask
5-6 LPM
6-10 LPM / Face Mask
0.3-0.45
0.35-0.55
Non Rebreather Mask/High Flow Nasal Canula
15 LPM / Non rebreather:
80%

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