Table 1.
Baseline characteristics of the included patients.
| Overall (n = 314) | Bicarbonate (n = 56) | No Bicarbonate (n = 258) | p value | |
|---|---|---|---|---|
| Age, years | 67 (50–80) | 67 (56–80) | 67 (49–80) | 0.532 |
| Male gender - no. (%) | 180 (57.3) | 28 (50.0) | 152 (58.9) | 0.236 |
| ED admission diagnosis - no. (%) | 0.063 | |||
| Acute kidney injury | 23 (7.3) | 9 (16.1) | 14 (5.4) | |
| Cardiac arrest | 30 (9.6) | 6 (10.7) | 24 (9.3) | |
| Diabetic ketoacidosis | 36 (11.5) | 5 (8.9) | 31 (12.0) | |
| Other | 225 (71.7) | 36 (64.3) | 189 (73.3) | |
| Baseline pathology | ||||
| Creatinine, μmol/L | 82 (63–125) | 85 (62–106) | 82 (63–130) | 0.777 |
| Platelet, x 109/L | 239 (184–299) | 246 (195–295) | 236 (184–299) | 0.658 |
| Haemoglobin, g/L | 125 (102–139) | 129 (111–140) | 124 (100–138) | 0.157 |
| White blood cell count, 109/L | 8.1 (6.2–11.2) | 8.6 (5.9–11.6) | 8.0 (6.3–11.1) | 0.893 |
| First vital signs | ||||
| Heart rate, bpm | 100 (80–120) | 92 (78–113) | 100 (80–120) | 0.146 |
| Systolic blood pressure, mmHg | 115 (93–136) | 110 (93–140) | 115 (94–135) | 0.977 |
| Diastolic blood pressure, mmHg | 68 (55–80) | 68 (53–80) | 68.5 (55–80) | 0.516 |
| Respiratory rate, breaths/min | 22 (18–29) | 22 (18–28) | 22 (18–30) | 0.690 |
| SpO2, % | 98 (94–100) | 98 (96–100) | 98 (94–100) | 0.024 |
| FiO2 | 0.21 (0.21–0.51) | 0.21 (0.21–0.50) | 0.21 (0.21–0.52) | 0.403 |
| SpO2/FiO2 ratio | 429 (182–467) | 467 (196–471) | 419 (174–467) | 0.080 |
| Temperature, ºC | 35.9 (35.2–36.6) | 35.7 (34.4–36.4) | 35.9 (35.2–36.6) | 0.212 |
| First blood gas | ||||
| Sample - no. (%) | 0.064 | |||
| Arterial | 173 (55.1) | 23 (41.1) | 150 (58.1) | |
| Venous | 124 (39.5) | 31 (55.4) | 93 (36.0) | |
| Unknown | 17 (5.4) | 2 (3.6) | 15 (5.8) | |
| pH | 7.18 (7.06–7.25) | 7.09 (6.96–7.19) | 7.19 (7.08–7.26) | <0.001 |
| PaCO2, mmHg | 35 (28–40) | 31 (25–37) | 36 (28–43) | 0.001 |
| Bicarbonate, mmol/L | 13 (8–17) | 10 (6–12) | 14 (9–17) | <0.001 |
| Base excess, mmol/L | −10.2 (−14.8–−6.6) | −16.5 (−19.4–−10.6) | −9.7 (−14.2–−6.3) | 0.026 |
| Sodium, mmol/L | 135 (130–139) | 135 (129–139) | 135 (131–139) | 0.455 |
| Potassium, mmol/L | 4.7 (3.9–5.7) | 5.3 (4.1–6.3) | 4.6 (3.9–5.5) | 0.016 |
| Chloride, mmol/L | 106 (101–110) | 104 (98–112) | 106 (101–110) | 0.879 |
Data are median (quartile 25th - quartile 75th) or N (%).
Abbreviations: ED: emergency department; ICU: intensive care unit.