A comparison of induced and expectorated sputum for the microbiological diagnosis of community acquired pneumonia.
BACKGROUND
Sputum induction has proved useful in the diagnosis of Pneumocystis carinii pneumonia and mycobacterial infections but there are scant data on its use in the diagnosis of community-acquired pneumonia (CAP).


OBJECTIVE
To better define the usage of sputum induction by hypertonic saline in the setting of CAP.


METHODS
A retrospective review of records of patients admitted to a community teaching hospital in the year 1995 with a diagnosis of CAP.


RESULTS
Of 492 patients admitted with CAP, 71 (14%) had attempted sputum induction. A group of 66 patients with CAP and attempted sputum collection by spontaneous expectoration was compared with this group. Sputum induction failed to yield a sample in 22 patients (31%). Forty-five of 49 patients (92%) with induced sputum had received prior antibiotics as compared to 23 of 34 patients (68%) with expectorated samples (p < 0.05), due to sputum induction often being attempted later in the hospital course. The diagnostic yield of sputum induction was 14 of 71 (20%) compared to 16 out of 66 (24%) for attempted spontaneously expectorated samples. Antibiotic therapy was changed for 5 of 34 patients (15%) who spontaneously expectorated samples and for 9 of 49 patients (18%) with successful induction.


CONCLUSIONS
Sputum induction is effective in obtaining sputum in some patients with CAP who fail to expectorate a sample. Attempting induction early, preferably before starting antibiotics, may increase its diagnostic yield.
Bandyopadhyay
T
T
Pulmonary Division, University of Connecticut School of Medicine, Farmington, Conn., USA.
Gerardi
D A
DA
Metersky
M L
ML
D000280:Administration, Inhalation; D000368:Aged; D001419:Bacteria / Q000302:isolation & purification; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000382:microbiology; D003237:Connecticut; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D018410:Pneumonia, Bacterial / Q000175:diagnosis* / Q000382:microbiology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012965:Sodium Chloride / Q000008:administration & dosage; D013183:Sputum / Q000378:metabolism* / Q000382:microbiology*
D012965:Sodium Chloride