Alveolar-arterial oxygen gradient, pneumonia severity index and outcomes in patients hospitalized with community acquired pneumonia.
The alveolar-arterial oxygen gradient (DeltaA-a) provides a useful assessment of ventilation/perfusion (V/Q) abnormalities. The objectives of the present study were to: (i) examine the correlation between the DeltaA-a and the pneumonia severity index (PSI); and (ii) determine whether these measures were comparable in predicting clinical outcomes. The present study was conducted at a 750-bed teaching hospital. It examined a retrospective cohort of 255 patients with community acquired pneumonia (CAP) over a 2 year period. Association between the CAP and DeltaA-a was investigated by regression models and correlation, as well as two logistic models for subjects bifurcated by low-risk/moderate-to-high risk. The decision levels (DL) for both PSI and DeltaA-a were then compared as predictors of both length of stay (LOS) and survival. The correlation between PSI and DeltaA-a was strong (rho = 0.76; P < 0.0001) and was best modelled by a curvilinear relationship. Both logistic models indicated a strong association (P < 0.001) between DeltaA-a and PSI and yielded an optimal DL for the DeltaA-a of < 89 mmHg. Inter-test agreement of DeltaA-a with PSI was 76.9% (kappa = 0.60; 95% confidence interval 0.47-0.72; P < 0.0001). At < 89 mmHg, the odds ratios for LOS were similar to those at PSI = 90 in predicting LOS in the range 3-7 days, inclusive. There was no significant difference in the ability of DeltaA-a and PSI to predict survival for either the low- or high-risk group (P = 0.363 and P = 0.951, respectively). The DeltaA-a correlates well with PSI and performs comparably in predicting two major outcomes in subjects hospitalized with CAP.
Division of Pulmonary Diseases, Department of Medicine, School of Graduate Medical Education, Seton Hall University, South Orange, NJ 07079-2689, USA.
Mahmoud Q
MQ
Moammar
Hamad M
HM
Azam
Adel I
AI
Blamoun
Ashraf O
AO
Rashid
Medhat
M
Ismail
M Anees
MA
Khan
Vincent A
VA
DeBari
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001981:Bronchial Arteries / Q000503:physiopathology*; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006760:Hospitalization; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D018410:Pneumonia, Bacterial / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology*; D011379:Prognosis; D011650:Pulmonary Alveoli / Q000098:blood supply / Q000503:physiopathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult