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Table 1 Baseline characteristics of the included patients

From: Intraoperative low tidal volume ventilation and the risk of ICD-10 coded delirium and the use for antipsychotic medications

  Low Tidal Volume
(n = 614)
Conventional Tidal Volume
(n = 592)
Age, years 65.0 (54.0 – 72.0) 64.0 (55.0 – 72.0)
Male gender 366 (59.6) 346 (58.4)
Body weight, kg
  Actual 80.0 (68.0 – 95.0) 80.5 (70.5 – 94.0)
  Predicted 63.3 (56.0 – 70.6) 64.2 (55.1 – 70.6)
Body mass index, kg/m2 27.9 (24.4 – 32.5) 28.1 (25.1 – 32.0)
ARISCAT risk score 26.0 (19.0 – 37.0) 26.0 (19.0 – 35.8)
  Low 193 (34.8) 196 (37.8)
  Moderate 324 (58.5) 282 (54.4)
  High 37 (6.7) 40 (7.7)
Preoperative SpO2, % 97.0 (96.0 – 98.0) 97.0 (96.0 – 98.0)
Preoperative HCO3, mmol/L 26.0 (24.0 – 27.0) 26.0 (24.0 – 28.0)
Preoperative haemoglobin, g/dL 138.0 (127.0 – 149.0) 138.0 (124.0 – 149.0)
Preoperative creatinine, mg/dL 0.88 (0.74 – 1.06) 0.87 (0.75 – 1.06)
Co-morbidities
  Diabetes mellitus 119 (19.4) 126 (21.3)
  Hypertension 301 (49.1) 327 (55.3)
  Coronary artery disease 93 (15.2) 100 (16.9)
  Chronic renal disease 56 (9.1) 67 (11.3)
  Chronic liver disease 48 (7.8) 52 (8.8)
  Current smoker 100 (16.3) 109 (18.4)
  COPD 62 (10.1) 65 (11.0)
  Asthma 66 (10.7) 68 (11.5)
  Interstitial lung disease 8 (1.3) 2 (0.3)
  Bronchiectasis 1 (0.2) 1 (0.2)
  Obstructive sleep apnoea 59 (9.6) 63 (10.6)
  Obesitya 225 (37.8) 207 (36.8)
  Recent LRTI 8 (1.3) 8 (1.4)
Type of Surgery
  Abdominal 348 (56.7) 333 (56.3)
  Laparoscopic 158 / 348 (45.4) 170 / 333 (51.1)
  General 6 (1.0) 2 (0.3)
  Ear, nose and throat 17 (2.8) 13 (2.2)
  Orthopaedic 43 (7.0) 46 (7.8)
  Plastic 31 (5.0) 36 (6.1)
  Spine 125 (20.4) 120 (20.3)
  Vascular 29 (4.7) 28 (4.7)
  Others 15 (2.4) 13 (2.2)
Duration of surgery, minutes 189.5 (135.0 – 267.5) 185.0 (140.5 – 249.5)
  1. Data are presented as median (quartile 25—quartile 75) or N (%)
  2. ARISCAT Assess Respiratory Risk in Surgical Patients in Catalonia, COPD chronic obstructive pulmonary disease, HCO3 bicarbonate, LRTI lower respiratory tract infection, SpO2 pulse oximetry
  3. a defined as BMI > 30 kg/m2