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.
Moammar
Mahmoud Q
MQ
Division of Pulmonary Diseases, Department of Medicine, School of Graduate Medical Education, Seton Hall University, South Orange, NJ 07079-2689, USA.
Azam
Hamad M
HM
Blamoun
Adel I
AI
Rashid
Ashraf O
AO
Ismail
Medhat
M
Khan
M Anees
MA
DeBari
Vincent A
VA
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