Patient characteristics
| . | Trigger < 8 g/dL (n = 29) . | Trigger < 9.7 g/dL (n = 29) . |
|---|---|---|
| Age, mean ± SD, y | 71.3 ± 9.4 | 73.7 ± 7.3 |
| Male sex, n (%) | 19 (65.5) | 18 (62.1) |
| BMI, mean ± SD, kg/m2 | 25.3 ± 5.8 | 24.8 ± 3.8 |
| Operation, n (%) | ||
| Lower limb bypass | 17 (58.6) | 16 (55.2) |
| Abdominal aortic aneurysm* | 12 (41.4) | 13 (44.8) |
| Time of randomization, n (%) | ||
| The day before surgery | 2 (6.9) | 3 (10.3) |
| During surgery | 20 (69.0) | 21 (72.4) |
| After end of surgery | 7 (24.1) | 5 (17.2) |
| Any cardiovascular disease, n (%) | 26 (89.7) | 23 (79.3) |
| Lower extremity artery disease | 20 (69.0) | 17 (58.6) |
| Claudication | 4 (13.8) | 1 (3.4) |
| Pain at rest | 4 (13.8) | 5 (17.2) |
| Wound/gangrene | 12 (41.4) | 11 (37.9) |
| Angina | 3 (10.3) | 5 (17.2) |
| Stroke or TIA | 8 (27.6) | 5 (17.2) |
| Previous CABG or PCI | 3 (10.3) | 5 (17.2) |
| Congestive heart failure | 1 (3.4) | 2 (6.9) |
| Heart valve disease | 3 (10.3) | 4 (13.8) |
| Acute myocardial infarction | 0 (0.0) | 6 (20.7) |
| Pacemaker | 0 (0.0) | 0 (0.0) |
| Any cardiovascular risk factor, n (%) | 29 (100.0) | 28 (96.6) |
| Arterial hypertension | 19 (65.5) | 22 (75.9) |
| Smoker | 12 (41.4) | 11 (37.9) |
| COPD | 6 (20.7) | 8 (27.6) |
| Hypercholesterolemia | 22 (75.9) | 26 (89.7) |
| Chronic renal failure | 3 (10.3) | 6 (20.7) |
| Diabetes mellitus | 8 (27.6) | 6 (20.7) |
| ASA score, mean ± SD | 3.0 ± 0.27 | 2.9 ± 0.41 |
| ASA class, n (%) | ||
| ASA1 | 0 (0.0) | 0 (0.0) |
| ASA2 | 1 (3.4) | 4 (13.8) |
| ASA3 | 27 (93.1) | 24 (82.8) |
| ASA4 | 1 (3.4) | 1 (3.4) |
| Preoperative Hb, mean ± SD, g/dL | 12.3 ± 1.8 | 12.4 ± 2.2 |
| Preoperative creatinine, median (IQR), µmol/L | 73 (62 to 98) | 87 (66 to 108) |
| NIRS at baseline†, mean ± SD | ||
| Regional cerebral oxygenation, % | 60.8 ± 9.6 | 59.5 ± 9.1 |
| Regional biceps muscle oxygenation, % | 69.8 ± 8.9 | 68.2 ± 9.8 |
| . | Trigger < 8 g/dL (n = 29) . | Trigger < 9.7 g/dL (n = 29) . |
|---|---|---|
| Age, mean ± SD, y | 71.3 ± 9.4 | 73.7 ± 7.3 |
| Male sex, n (%) | 19 (65.5) | 18 (62.1) |
| BMI, mean ± SD, kg/m2 | 25.3 ± 5.8 | 24.8 ± 3.8 |
| Operation, n (%) | ||
| Lower limb bypass | 17 (58.6) | 16 (55.2) |
| Abdominal aortic aneurysm* | 12 (41.4) | 13 (44.8) |
| Time of randomization, n (%) | ||
| The day before surgery | 2 (6.9) | 3 (10.3) |
| During surgery | 20 (69.0) | 21 (72.4) |
| After end of surgery | 7 (24.1) | 5 (17.2) |
| Any cardiovascular disease, n (%) | 26 (89.7) | 23 (79.3) |
| Lower extremity artery disease | 20 (69.0) | 17 (58.6) |
| Claudication | 4 (13.8) | 1 (3.4) |
| Pain at rest | 4 (13.8) | 5 (17.2) |
| Wound/gangrene | 12 (41.4) | 11 (37.9) |
| Angina | 3 (10.3) | 5 (17.2) |
| Stroke or TIA | 8 (27.6) | 5 (17.2) |
| Previous CABG or PCI | 3 (10.3) | 5 (17.2) |
| Congestive heart failure | 1 (3.4) | 2 (6.9) |
| Heart valve disease | 3 (10.3) | 4 (13.8) |
| Acute myocardial infarction | 0 (0.0) | 6 (20.7) |
| Pacemaker | 0 (0.0) | 0 (0.0) |
| Any cardiovascular risk factor, n (%) | 29 (100.0) | 28 (96.6) |
| Arterial hypertension | 19 (65.5) | 22 (75.9) |
| Smoker | 12 (41.4) | 11 (37.9) |
| COPD | 6 (20.7) | 8 (27.6) |
| Hypercholesterolemia | 22 (75.9) | 26 (89.7) |
| Chronic renal failure | 3 (10.3) | 6 (20.7) |
| Diabetes mellitus | 8 (27.6) | 6 (20.7) |
| ASA score, mean ± SD | 3.0 ± 0.27 | 2.9 ± 0.41 |
| ASA class, n (%) | ||
| ASA1 | 0 (0.0) | 0 (0.0) |
| ASA2 | 1 (3.4) | 4 (13.8) |
| ASA3 | 27 (93.1) | 24 (82.8) |
| ASA4 | 1 (3.4) | 1 (3.4) |
| Preoperative Hb, mean ± SD, g/dL | 12.3 ± 1.8 | 12.4 ± 2.2 |
| Preoperative creatinine, median (IQR), µmol/L | 73 (62 to 98) | 87 (66 to 108) |
| NIRS at baseline†, mean ± SD | ||
| Regional cerebral oxygenation, % | 60.8 ± 9.6 | 59.5 ± 9.1 |
| Regional biceps muscle oxygenation, % | 69.8 ± 8.9 | 68.2 ± 9.8 |
There was no between-group difference in race, as all patients were white. The only statistically significant baseline difference between groups was previous AMI (P = .023).
ASA, American Society of Anesthesiologists; BMI, body mass index; CABG, coronary artery bypass grafting; COPD, chronic obstructive pulmonary disease; PCI, percutaneous coronary intervention; TIA, transient ischemic attack.
One patient in the AAA-stratum of the high-trigger (< 9.7g/dL) group underwent aorto-iliac bifurcated prosthesis surgery on the indication aorto-iliac occlusive disease. Otherwise, all patients in the AAA-stratum had aneurysmal disease.
Baseline was defined as the point at which the patient was normovolemic according to the goal-directed fluid strategy after anesthesia was induced and before starting surgery. The NIRS readings before O2-supplementation and induction of anesthesia were similar to this baseline (supplemental Table 3.0).