COPD
                                ====
þ COPD and PE
 - 25% of COPD exacerbations (requiring admission to the floor but not the ICU) 
   without another explanation are PEs
   [Tillie-Leblond, I., C. H. Marquette, et al. (2006). "Pulmonary embolism in 
   patients with unexplained exacerbation of chronic obstructive pulmonary 
   disease: prevalence and risk factors." Ann Intern Med 144(6): 390-396.]
   BACKGROUND: Diagnosis of pulmonary embolism (PE) is difficult in patients 
   with chronic obstructive pulmonary disease (COPD) and exacerbation. 
   OBJECTIVE: To evaluate PE in patients with COPD and exacerbation of unknown 
   origin and explore factors associated with PE. DESIGN: Prospective cohort 
   study. SETTING: University-affiliated hospital in France. PATIENTS: 211 
   consecutive patients, all current or former smokers with COPD, who were 
   admitted to the hospital for severe exacerbation of unknown origin and did 
   not require invasive mechanical ventilation. MEASUREMENTS: Spiral computed 
   tomography angiography (CTA) and ultrasonography within 48 hours of admission 
   and assessment of the Geneva score. Patients were classified as PE positive 
   (positive results on CTA or negative results on CTA and positive results on 
   ultrasonography) or PE negative (negative results on CTA and negative results 
   on ultrasonography or negative results on CTA and no recurrence of PE at 
   follow-up 3 months later). RESULTS: 49 of 197 patients (25% [95% CI, 19% to 
   32%]) met the diagnostic criteria for PE. Clinical factors associated with PE 
   were previous thromboembolic disease (risk ratio, 2.43 [CI, 1.49 to 3.94]), 
   malignant disease (risk ratio, 1.82 [CI, 1.13 to 2.92]), and decrease in 
   PaCO2 of at least 5 mm Hg (risk ratio, 2.10 [CI, 1.23 to 3.58]). A total of 
   9.2% (CI, 4.7% to 15.9%) of patients with a low-probability Geneva score 
   received a diagnosis of PE. An exploratory analysis suggested that 
   substituting malignant disease for recent surgery in the Geneva score might 
   improve its performance in excluding PE in this sample who were more likely 
   to have malignant disease than to have had recent surgery. However, this 
   improvement seems insufficient to exclude PE with enough certainty to 
   withhold therapy for low-risk patients on the basis of the modified score. 
   LIMITATIONS: This study was done in only 1 center. Patients with COPD 
   requiring invasive mechanical ventilation in the intensive care unit were not 
   included. The upper bound of the 95% CI for the low probability of PE 
   according to the Geneva score is too high to rule out PE. The classification 
   of COPD exacerbation of unknown origin was based on the clinician's 
   assessment, not on a standard evaluation for all patients. CONCLUSION: This 
   study showed a 25% prevalence of PE in patients with COPD hospitalized for 
   severe exacerbation of unknown origin. Three clinical factors are associated 
   with the increased risk for PE. The Geneva score and the modified Geneva 
   score should be prospectively evaluated in patients with COPD.


]

þ Color of Sputum
 - Those with purulent green sputum benefit from antibiotics, those with white
   sputum don't.
   [Stockley RA, O'Brien C, Pye A, Hill SL. Relationship of sputum color
   to nature and outpatient management of acute exacerbations of COPD. Chest
   2000;117(6):1638-45.]

þ Cause of hypercarbia from giving O2 to COPD patients
 - clasically thought to be diminishing the hypoxic drive to breathe.
 - more recent research suggests V/Q mismatching and changes in dead space.
   [Hanson CW 3rd, Marshall BE, Frasch HF, Marshall C. Causes of hypercarbia
   with oxygen therapy in patients with chronic obstructive pulmonary disease.
   Crit Care Med 1996 Jan;24(1):23-8.]
   Abstract: <COPDA.TXT -Hanson>
   [Tinits P. Oxygen therapy and oxygen toxicity. Ann Emerg Med 1983
   May;12(5):321-8.]
   Abstract: <COPDA.TXT -Tinits>