Table 2 Perioperative characteristics

Preoperative Peripheral Saturation of Oxyhemoglobin (SpO₂), %

97.7 (2.0)

97.1 (2.2)

< 0.0001

 Emergency Surgery

4 (1.5)

57 (6.1)

0.0472

 Abdominal/Pelvic Surgery

174 (65.4)

371 (39.6)

0.0003

 Surgery Duration, hours

3.9 (2.1)

3.6 (2.0)

0.1034

 Anesthesia Duration, hours

4.8 (2.2)

4.6 (2.2)

0.3486

 Ventilatory Modes

0.4295

 Volume Controlled Ventilation

187 (70.3)

637 (68.1)

 Pressure Controlled Ventilation

47 (17.7)

131 (14.0)

 Assisted/Supported Ventilation

7 (2.6)

41 (4.4)

 Unspecified

25 (9.4)

126 (13.5)

 Median Exhaled Tidal Volume (VT), mL/kgPBW

8.0 (1.4)

8.0 (1.7)

0.1543

 Median Inspired Fraction of Oxygen (FiO2), %

53.9 (12.1)

54.6 (14.3)

0.4305

 Median End-Expiratory Pressure (PEEP), cmH₂O

5 (1)

5 (2)

0.9420

 Median Peak Inspiratory Pressure, cmH₂O

20.7 (4.9)

21.4 (5.5)

0.0218

 Estimated Blood Loss, mL

456.8 (948)

310.5 (531)

0.0106

 Urine Output, mL/kg/h

1.11 (1.26)

1.28 (1.61)

0.0750

 Crystalloids (ml/kg/hr)

6.97 (3.89)

6.14 (3.59)

0.0027

 Colloids (mL/kg/hr)

0.5 (1.2)

0.3 (0.7)

<.0001

 Any Blood Product transfused

33 (12.4)

99 (10.6)

0.4243

 Depolarizing neuromuscular blockade

97 (36.6)

343 (36.7)

0.9697

 Non-Depolarizing neuromuscular blockade

245 (92.1)

793 (84.8)

0.0223

 Neuromuscular blockade monitoring

194 (80.5)

555 (68.4)

0.0116

 Neostigmine Dose, mcg/kg

37.1 (24.3)

29.9 (23.8)

< 0.0001

 Propofol

98 (36.8)

413 (44.2)

0.0392

 Fentanyl

257 (96.6)

857 (91.6)

0.0331

 Hydromorphone

126 (47.4)

509 (54.4)

0.0222

 Morphine

8 (3.0)

61 (6.5)

0.0942

 Remifentanil

34 (12.8)

176 (18.8)

0.0064

 Ketamine

24 (9.0)

135 (14.4)

0.1382