Table 2.
Intraoperative Data
| Variables | Control Group (N = 44) |
Closed-loop Group (N = 45) |
Point Estimate (95% CI) |
P Value |
|---|---|---|---|---|
| Anesthesia duration (min) | 265 ± 144 | 274 ± 101 | 9 (−44 to 62) | 0.732 |
| Surgery duration (min) | 177 [117 to 267] | 203 [139 to 300] | 23 (−19 to 62) | 0.313 |
| Crystalloid volume (ml) | 2,000 [1,000 to 2,483] | 900 [688 to 1210] | −950 (−1,209 to −600) | < 0.001 |
| Colloid volume (ml) | 0 [0 to 0] | 700 [400 to 1500] | 600 (400 to 900) | < 0.001 |
| Blood component transfusion (%) | ||||
| Packed red blood cells | 1 (2.3) | 1 (2.2) | > 0.999 | |
| Fresh frozen plasma | 0 | 0 | > 0.999 | |
| Platelets | 0 | 0 | > 0.999 | |
| Total IN (ml) | 2,000 [1,500 to 2,688] | 1,600 [1,011 to 2,610] | −225 (−600 to 192) | 0.299 |
| Urine output (ml) | 300 [150 to 488] | 330 [238 to 500] | 75 (−25 to 150) | 0.152 |
| Estimated blood loss (ml) | 150 [50 to 488] | 250 [100 to 725] | 50 (0 to 200) | 0.202 |
| Total OUT (ml) | 535 [255 to 1,015] | 780 [400 to 1,300] | 200 (0 to 430) | 0.063 |
| Fluid balance (ml) | 1,250 [850 to 1,888] | 875 [488 to 1380] | −350 (−650 to −50) | 0.028 |
| Ephedrine (mg) | 0 [0 to 9] | 0 [0 to 18] | 0 (0 to 2) | 0.405 |
| Phenylephrine (μg) | 0 [0 to 0] | 0 [0 to 0] | > 0.999 | |
| Patients under norepinephrine (%) | 11 (25) | 12 (27) | 1.7 (−17 to 20) | 0.857 |
| Patients under any kind of vasopressor agents, n (%) | 28 (64) | 31 (69) | 5 (−14 to 25) | 0.600 |
| Percentage case time with Bispectral Index [40 to 60] (%) | 56 [38 to 75] | 84 [74 to 89] | 22 (14 to 31) | < 0.001 |
| Percentage case time with Bispectral Index < 40 (%) | 29 [12 to 50] | 10 [3 to 19] | −18 (−28 to −9) | < 0.001 |
| Percentage case time with Bispectral Index > 60 (%) | 7 [1 to 13] | 3 [2 to 8] | −2 (−5 to 0) | 0.128 |
| Number of episode with suppression ratio > 10 > 1 min | 0 [0 to 1] | 0 [0 to 0] | 0 (0 to 0) | 0.707 |
| Intraoperative heart rate (beats/min) | 65 [59 to 74] | 68 [63 to 76] | 4 (0 to 8) | 0.094 |
| Intraoperative mean arterial pressure (mmHg) | 90 [82 to 95] | 84 [78 to 94] | −4 (−8 to 1) | 0.130 |
| Percentage case time with MAP < 60 mmHg | 0.8 [0 to 3.6] | 1.0 [0 to 3.2] | 0 (−0.5 to 0.4) | 0.703 |
| Number of effect site propofol modifications per hour | 5 [3 to 8] | 24 [18 to 32] | 18 (15 to 22) | < 0.001 |
| Number of effect site remifentanil modifications per hour | 4 [2 to 5] | 24 [21 to 30] | 21 (19 to 22) | < 0.001 |
| Total propofol consumption (mg · kg−1 · h−1) | 4.4 [3.3 to 5.5] | 3.8 [3.0 to 4.5] | −0.71 (−1.37 to −0.05) | 0.033 |
| Total remifentanil consumption (μg · kg−1 · min−1) | 0.12 ± 0.05 | 0.14 ± 0.04 | 0.02 (0.01 to 0.04) | 0.012 |
| 24-h morphine consumption (mg) | 4 [2 to 10] | 4 [2 to 8] | −0.5 (−4.0 to 0.0) | 0.313 |
| Mean tidal volume (ml · kg−1) | 6.6 [6.1 to 6.9] | 6.9 [6.7 to 7.1] | 0.31 (0.08 to 0.52) | 0.012 |
| Percentage case time with end-tidal carbon dioxide [32 to 38] mmHg (%) | 48 [21 to 80] | 80 [56 to 92] | 20.5 (5.5 to 37.6) | 0.004 |
| Percentage case time with end-tidal carbon dioxide < 32 mmHg (%) | 24 [5 to 54] | 8 [3 to 30] | −8 (−23 to 0) | 0.037 |
| Percentage case time with end-tidal carbon dioxide > 38 mmHg (%) | 2.2 [0.5 to 12.8] | 4.3 [1.1 to 7.7] | 0.4 (−1.2 to 2.1) | 0.537 |
| Total number of ventilation parameters modifications | 3 [2 to 5] | 13 [3 to 33] | 6 (1 to 18) | 0.001 |
Data are listed as number and percentage (%), or mean ± SD for continuous variables that were normally distributed or median [25th to 75th percentiles] if not normally distributed. Point estimates for group differences were estimated for Mann–Whitney U test as the median difference in the set of values representing all differences in pairings between the two groups. Bold indicates significant results with P value < 0.05. IN includes all fluid and blood products received during surgery. OUT includes estimated blood loss and urine output. MAP, mean arterial pressure.