Can spirometry, pulse oximetry and dyspnea scoring reflect respiratory failure in patients with chronic obstructive pulmonary disease exacerbation?
OBJECTIVE
To evaluate the extent to which oximetry, spirometry and dyspnea scoring can reflect hypoxemia and hypercapnia among patients admitted to the emergency department (ED) with acute exacerbations of chronic obstructive pulmonary disease.


METHODS
Spirometry, oxygen saturation by pulse oximetry (SpO2), arterial blood gas analysis and dyspnea scoring assessments were made in the ED. Correlations of these parameters were evaluated by means of Pearson's test. Pulse oximetry cutoff values to express hypoxemia were demonstrated by receiver operating characteristic (ROC) curves.


RESULTS
76 patients with a mean age of 68.0 years were included in the study. Mean spirometric values, expressed as percentages of predicted values, were forced expiratory volume in 1 s (FEV1) = 23.1 +/- 9%; forced vital capacity (FVC) = 32.8 +/- 11%, and mean FEV1/FVC = 72.4 +/- 21.6%. While there was a positive correlation between the SpO2, SaO2 and PaO2 values (r = 0.91 and 0.80, respectively), a negative correlation (r = -0.74) was observed between PaCO2 and SpO2. In determining hypoxemia, both SpO2 and FEV1 were sensitive (83.9 and 90.3%, respectively) while dyspnea scoring was the most sensitive (93.5%). In the evaluation by means of an ROC curve, a saturation of 88.5% for the pulse oximeter was the best cutoff value to reflect hypoxemia (sensitivity 95.6%, specificity 80.6%).


CONCLUSIONS
SpO2 alone appears to be as highly specific as a combination of other tests in the evaluation of hypoxemia. A cutoff value for SpO2 of < or = 88.5% is proposed as a criterion in screening for hypoxemia.
Güryay
Melek Sedef
MS
Department of Emergency Medicine, Faculty of Medicine, Dokuz Eylül University, Izmir, Turkey.
Ceylan
Emel
E
Günay
Türkan
T
Karaduman
Sevilay
S
Bengi
Fecri
F
Parlak
Ismet
I
Ciçek
Metin
M
Cimrin
Arif H
AH
D000368:Aged; D000369:Aged, 80 and over; D004417:Dyspnea / Q000209:etiology; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D000860:Hypoxia / Q000097:blood / Q000175:diagnosis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D012016:Reference Values; D012131:Respiratory Insufficiency / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D012680:Sensitivity and Specificity; D013147:Spirometry