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2. Objectives Reinforce Primer Material Apply Knowledge Sound Icon

3. 54 year old male smoker (1 ppd x 40 y) Increasing dyspnea, productive cough FHx and PMHx unremarkable Meds: nil Physical exam: RR 28, HR 110, bilateral wheezes, obese (height 176 cm, wt 161kg, BMI 52) Blood work remarkable for WBC 20, bands 12%, neuts 63%, Hgb 160 g/L Patient with Hypercapneic Respiratory Failure

4. Patient with Hypercapneic Respiratory Failure • Q1: How would you interpret the CXR? • Answer (Q1)

5. ABG: on 6 lpm in ED PO2 80 PCO2 83 pH 7.16 HCO3 32 sat 95%. Na 140 Cl 100 Q2: How would you interpret the ABG? Answer (Q2) Patient with Hypercapneic Respiratory Failure

6. Patient with Hypercapneic Respiratory Failure • Q3: With the information provided so far, what is your diagnosis? • Acute exacerbation of COPD • Obesity – Hypoventilation syndrome • Obstructive Sleep Apnea • Neuromuscular disease • Answer (Q3)

7. Repeat ABG after several days of NIMV shows the following on 4 lpm: PO2 69, PCO2 51, pH 7.42, HCO3 30. Q4: What is the next investigation that you would perform? CT chest PFT Level I sleep study EMG and nerve conduction studies Answer (Q4) Patient with Hypercapneic Respiratory Failure

8. Patient with Hypercapneic Respiratory Failure • Q5: How would you interpret the PFT? • Obstructive defect with partial reversibility • Obstructive defect with no reversibility • Restrictive defect • normal • Answer (Q5)

9. Patient with Hypercapneic Respiratory Failure • Q6: In the context of a restrictive defect, how do you interpret the low DLCO adjusted for VA in this setting? • Interstitial lung disease is causing the restrictive defect • An extrapulmonary problem is causing the restrictive defect • An extrapulmonary problem is causing the restrictive defect, complicated by a lung parenchymal problem • I give up trying to understand DLCO adjusted for VA

10. Patient with Hypercapneic Respiratory Failure Answer (Q6) DLCO adjusted for VA in the setting of a restrictive defect normal low • Extrapulmonary cause of restrictive defect • neuromuscular disease • chest wall abnormality (including obesity) • pleural thickening or effusion • abdominal distension • Pulmonary cause of restrictive defect • interstitial lung disease • extrapulmonary cause complicated by a co-existing lung problem (eg. atelectasis, scarring from recurrent aspiration, etc)

11. Patient with Hypercapneic Respiratory Failure • Case Summary • Patient did not have COPD • Hypercapnea not explained by the relatively high FEV1 • Patient found to have OSA

12. Patient with Hypercapneic Respiratory Failure • end of case