Table 2. Descriptive Statistics for Patients With Hidden Hypoxemia vs Patients Without Hypoxemiaa.
| Characteristic | Asian patients, mean (SE) | P value | Black patients, mean (SE) | P value | Hispanic patients, mean (SE) | P value | White patients, mean (SE) | P value | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hidden hypoxemia | No hypoxemia | Hidden hypoxemia | No hypoxemia | Hidden hypoxemia | No hypoxemia | Hidden hypoxemia | No hypoxemia | |||||
| No. (%) | 94 (4.9) | 1825 (95.1) | NA | 1789 (6.9) | 24 243 (93.1) | NA | 145 (6.0) | 2252 (94.0) | NA | 2831 (4.9) | 54 792 (95.1) | NA |
| Age, y | 63.93 (2.46) | 62.34 (0.51) | <.001 | 58.26 (0.51) | 57.76 (0.15) | <.001 | 57.48 (2.05) | 59.53 (0.52) | <.001 | 64.03 (0.41) | 64.29 (0.1) | <.001 |
| Sex, No. (%) | ||||||||||||
| Female | 36 (38.3) | 724 (39.7) | .89 | 862 (48.2) | 11 243 (46.4) | .11 | 75 (51.7) | 1028 (45.6) | .15 | 1241 (43.8) | 22 504 (41.1) | .01 |
| Male | 58 (61.7) | 1101 (60.3) | 927 (51.8) | 13 000 (53.6) | 70 (48.3) | 1224 (54.4) | 1590 (56.2) | 32 288 (58.9) | ||||
| Serum creatinine levels, mg/dL | ||||||||||||
| Before ABG | 1.73 (0.24) | 1.59 (0.07) | <.001 | 2.37 (0.09) | 2.27 (0.03) | <.001 | 1.79 (0.19) | 1.66 (0.04) | <.001 | 1.73 (0.04) | 1.46 (0.01) | <.001 |
| After ABG | 1.79 (0.31) | 1.44 (0.06) | <.001 | 2.2 (0.08) | 2.07 (0.02) | <.001 | 2.01 (0.33) | 1.6 (0.07) | <.001 | 1.53 (0.06) | 1.38 (0.01) | <.001 |
| Difference | 0.05 (0.19) | −0.1 (0.04) | <.001 | −0.21 (0.06) | −0.2 (0.02) | .08 | −0.15 (0.19) | −0.17 (0.04) | .33 | −0.17 (0.05) | −0.07 (0.01) | <.001 |
| Serum lactate levels, mg/dL | ||||||||||||
| Before ABG | 4.37 (0.82) | 2.87 (0.11) | <.001 | 3.4 (0.13) | 2.85 (0.03) | <.001 | 2.96 (0.45) | 2.87 (0.09) | .26 | 2.99 (0.1) | 2.56 (0.02) | <.001 |
| After ABG | 2.97 (0.65) | 2.32 (0.15) | <.001 | 3.27 (0.22) | 2.5 (0.04) | <.001 | 3.4 (0.8) | 2.24 (0.13) | <.001 | 2.51 (0.14) | 2.15 (0.03) | <.001 |
| Difference, | −1.61 (0.86) | −1.14 (0.2) | <.001 | −0.34 (0.25) | −0.82 (0.05) | <.001 | −0.41 (0.79) | −1.14 (0.18) | <.001 | −0.68 (0.2) | −0.74 (0.04) | .00 |
| Long-term clinical outcomes | ||||||||||||
| Hospital LOS, db | 13.63 (1.81) | 13.18 (0.5) | .02 | 13.51 (0.58) | 16.48 (0.18) | .00 | 14.01 (2.11) | 13.18 (0.56) | .00 | 10.67 (0.35) | 11.19 (0.07) | .00 |
| In-hospital death, No. (%) | 20 (21.3) | 286 (15.7) | .13 | 369 (20.6) | 3557 (14.7) | <.001 | 35 (24.1) | 439 (19.5) | .06 | 738 (26.1) | 8238 (15.0) | <.001 |
| SOFA scorec | ||||||||||||
| At the time of ABG | ||||||||||||
| CVSOFA | 0.61 (0.2) | 0.73 (0.06) | <.001 | 0.98 (0.07) | 0.85 (0.02) | <.001 | 1.05 (0.15) | 1.03 (0.03) | .14 | 1.13 (0.03) | 0.99 (0.01) | <.001 |
| RSOFA | 1.56 (0.32) | 1.26 (0.06) | <.001 | 1.87 (0.12) | 1.4 (0.03) | <.001 | 2.02 (0.17) | 1.44 (0.04) | <.001 | 1.81 (0.04) | 1.38 (0.01) | <.001 |
| SOFA | 6.03 (0.75) | 5.82 (0.15) | <.001 | 4.98 (0.25) | 5.26 (0.06) | <.001 | 5.09 (0.54) | 5.37 (0.09) | <.001 | 5.27 (0.1) | 5.22 (0.03) | <.001 |
| 24 h After ABG | ||||||||||||
| CVSOFA | 1.52 (0.2) | 1.36 (0.05) | <.001 | 7.02 (0.29) | 6.33 (0.07) | <.001 | 1.56 (0.15) | 1.32 (0.03) | <.001 | 1.48 (0.03) | 1.26 (0.01) | <.001 |
| RSOFA | 1.58 (0.28) | 1.27 (0.07) | <.001 | 1.87 (0.1) | 1.4 (0.03) | <.001 | 2.01 (0.18) | 1.45 (0.04) | <.001 | 1.79 (0.04) | 1.37 (0.01) | <.001 |
| SOFA | 7.17 (0.77) | 5.62 (0.17) | <.001 | 8.17 (0.27) | 7.26 (0.08) | <.001 | 7.49 (0.54) | 6.3 (0.1) | <.001 | 7.2 (0.1) | 6.3 (0.02) | <.001 |
Abbreviations: ABG, arterial blood gas; CVSOFA, cardiovascular Sequential Organ Failure Assessment; LOS, length of stay; NA, not applicable; RSOFA, respiratory Sequential Organ Failure Assessment; SOFA, Sequential Organ Failure Assessment.
SI conversion factors: To convert creatinine to micromoles per liter, multiply by 88.4; lactate to millimoles per liter, multiply by 0.111.
The table presents baseline patient demographic (age, sex) and clinical characteristics (SOFA, CVSOFA) at the time of ABG, stratified by race and ethnicity. When applicable, SEs are provided. These were obtained using simple bootstrap with 100 iterations.
Length of stay computed for survivors only.
SOFA scores available only for patients in the Electronic Intensive Care Unit–Clinical Research Database and Medical Information Mart for Intensive Care databases.