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Table 1 Patients demographics and surgery–related characteristics

From: The Association of Intraoperative driving pressure with postoperative pulmonary complications in open versus closed abdominal surgery patients – a posthoc propensity score–weighted cohort analysis of the LAS VEGAS study

 

All patients

(N = 2.034)

Closed

abdominal surgery

(N = 906)

Open

abdominal surgery

(N = 1.128)

P–value

Absolute Difference

Age, years

54 [40 to 67]

49 [36 to 64]

58 [45 to 69]

<  0.001

9 [6 to 21]

Gender, male (%)

42% (846/2034)

34% (306/906)

48% (540/1128)

<  0.001

14% [9 to 18%]

Ethnicity, % (n/N)

   

0.194

 

 Caucasian

88% (1787/2.030)

87% (786/902)

89% (1001/1.128)

  

 Black

1% (20/2.030)

1% (6/902)

1% (14/1.128)

  

 Asian

3% (58/2.030)

4% (33/902)

2% (25/1.128)

  

 Other

8% (165/2.030)

8% (77/902)

8% (88/1.128)

  

BMI (Kg∙m−2)

26.2 [23.3 to 30.0]

26.7 [23.6 to 31.3]

25.8 [22.9 to 29.3]

<  0.001

0.8 [0.04 to 1.6]

Weight (kg)

75.0 [65.0 to 87.0]

77.0 [68.0 to 93.0]

74.0 [64.0 to 85.0]

0.001

3 [8 to 13]

PBW (kg)

60.6 [55.1 to 69.0]

59.7 [54.2 to 67.8]

61.5 [56.0 to 69.7]

<  0.001

1.82 [1.8 to 2]

ASA class, % (n/N)

   

<  0.001

 

 1

24% (495/2.028)

31% (276/904)

20% (219/1.124)

  

 2

49% (989/2.028)

53% (477/904)

46% (512/1.124)

  

 3

24% (488/2.028)

16% (146/904)

30% (342/1.124)

  

 4

3% (53/2.028)

1% (5/904)

4% (48/1.124)

  

 5

0% (3/2.028)

0% (0/904)

0% (3/1.124)

  

ARISCAT score

26 [18 to 38]

18 [15 to 31]

34 [18 to 41]

<  0.001

16 [16 to 16]

ARISCAT class, % (n/N)

   

<  0.001

 

  < 26

51% (985/1.945)

68% (607/888)

36% (378/1.057)

  

 26–44

38% (741/1.945)

26% (231/888)

48% (510/1.057)

  

  > 44

11% (219/1.945)

6% (50/888)

16% (169/1.057)

  

Preop. SpO2,%

98 [96 to 99]

98 [96 to 99]

97 [96 to 99]

0.004

0 [0 to 3]

Current smoker, %

20% (413/2.034)

21% (79/906)

20% (222/1.128)

0.468

2% [3 to 7%]

Chronic comorbidity, % (n/N)

 Metastatic cancer

7% (138/2.034)

2% (22/906)

10% (116/1.128)

<  0.001

8% [5 to 9%]

 Chronic kidney failure

4% (81/2.034)

1% (13/906)

6% (68/1.128)

<  0.001

5% [2 to 6%]

 COPD

7% (138/2.034)

7.% (83/906)

6% (55/1.128)

0.290

1% [1 to 3%]

 Heart failure

7% (143/2.034)

6% (53/906)

8% (90/1.128)

0.075

2% [1 to 4%]

 OSAS

2% (42/2.034)

3% (27/906)

1% (15/1.128)

0.015

2% [1 to 3%]

 Neuromuscular diseasea

1% (17/2.034)

1% (6/906)

1% (11/1.128)

0.599

0.3% [0.3 to 1%]

 Liver dysfunction

1% (29/2.034)

1% (5/906)

2% (24/1.128)

0.210

1% [1 to 2%]

Functional Status, % (n/N)

   

<  0.001

 

 Independent

92% (1872/2.034)

96% (867/906)

89% (1005/1.128)

  

 Partially dependent

7% (135/2.034)

4% (32/906)

9% (103/1.128)

  

 Totally dependent

1% (27/2.034)

1% (7/906)

2% (20/1.128)

  

Preop. resp. infection,% (n/N)

5% (95/2.034)

4% (35/906)

5% (60/1.128)

0.150

2% [0.5 to 3%]

Preop. Hb (g∙dl−1), % (n/N)

13.4 [12.2 to 14.0]

13.5 12.6 to 14.5]

13.3 [11.9 to 14.5]

<  0.001

0.2 [0.3 to 1]

Preop. anemia (Hb ≤ 10 g dl−1)

9% (1738/1.846)

3% (21/798)

8% (87/1.048)

<  0.001

5% [3 to 7%]

Preop. creatinine (g∙dl− 1)

0.8 [0.7 to 1.0]

0.8 [0.7 to 1.0]

0.9 [0.7 to 1.1]

<  0.001

0.04 [0.01 to 0.1]

Preop transfusion, % (n/N)

1% (23/2.034)

0% (3/906)

2% (20/1.128)

0.004

1% [0.5 to 1%]

Surgical procedureb, % (n/N)

 Lower GI

26% (286/1.098)

14% (124/906)

31% (346/1.128)

<  0.001

17% [13 to 20%]

 Upper GI, HBP

28% (303/1.098)

47% (429/906)

20% (222/1.128)

<  0.001

27% [23 to 31%]

 Vascular surgery

2% (25/1.098)

0% (0/906)

3% (30/1.128)

<  0.001

2% [1 to 3%]

 Aortic surgery

2% (19/1.098)

0% (0/906)

2% (20/1.128)

<  0.001

1% [1 to 2%]

 Urological

19% (204/1.098)

9% (81/906)

14% (162/1.128)

<  0.001

5% [2 to 8%]

 Gynaecological

18% (195/1.098)

26% (233/906)

17% (188/1.128)

<  0.001

9% [6 to 12%]

 Endocrine surgery

1% (9/1.098)

1% (5/906)

1% (10/1.128)

0.443

0.3% [0.5 to 1%]

 Transplant

2% (18/1.098)

0% (0/906)

2% (20/1.128)

<  0.001

2% [1 to 3%]

 Neurosurgery

5% (52/1.098)

0% (1/906)

10% (109/1.128)

<  0.001

9% [8 to 11%]

 Other procedure

3% (30/1.098)

5% (43/906)

19% (214/1.128)

<  0.001

14% [11 to 17%]

Urgency of Surgeryc, % (n/N)

   

<  0.001

 

 Elective

84% (1705/2.034)

87% (792/906)

81% (913/1.128)

  

 Urgent

12% (235/2.034)

9% (85/906)

13% (150/1.128)

  

 Emergency

4% (94/2.034)

4% (29/906)

6% (65/1.128)

  

Duration of surgeryd, min

86 [55 to 149]

70 [50 to 110]

105 [65 to 172]

<  0.001

35 [21 to 43]

Duration of anaesthesiae, min

115 [80 to 190]

100 [71 to 147]

140 [91 to 205]

<  0.001

40 [20 to 60]

Time of surgery, % (n/N)

   

<  0.843

0.2 [0.2 to 1]

 Daytimef

95% (1925/2034)

95% (859/906)

95%(1066/1128)

  

 Night–time

5% (109/2034)

5% (47/906)

5% (962/1128)

  

Antibiotic prophylaxis, % (n/N)

80% (1.628/2.034)

73% (662/906)

84% (956/1.127)

0.005

11% [8 to 15%]

Mean arterial pressure, mmHg

82 [74 to 92]

84 [76 to 94]

80 [72 to 90]

<  0.001

4 [4 to 7]

Heart rate, beats∙min

72 [63 to 82]

73 [64 to 82]

72 [62 to 83]

0.276

1 [3 to 11]

Intraop. procedures, % (n/N)

 Epidural anesthesia

12% (237/2.034)

3% (25/906)

19% (212/1128)

<  0.001

16% [13 to 18%]

 Opioid

   

<  0.001

 

  Short–acting

18% (367/2.015)

22% (193/900)

16% (174/1.115)

  

  Long–acting

70% (1410/2.015)

62% (561/900)

76% (849/1.115)

  

  Both

12% (238/2.015)

16% (146/900)

8% (92/1.115)

  

 Neuromuscular Blockade

97% (1965/2.028)

97% (876/903)

97% (1089/1.125)

0.887

0.2% [0.1 to 1%]

 Neuromuscular Monitoring

23% (474/2.032)

25% (230/906)

22% (244/1.126)

0.055

3% [0 to 7%]

 Neuromuscular Reversal

41% (827/2.024)

49% (437/901)

35% (390/1.123)

<  0.001

14% [9 to 18%]

 TIVA

10% (211/2.027)

11% (102/902)

10% (109/1.125)

0.266

1% [1 to 4%]

 Transfusion

6% (113/2.034)

1% (13/906)

9% (100/1.128)

<  0.001

7% [6 to 9%]

 Total Fluids (mL∙ kg−1)

18 [12 to 30]

15 [13 to 30]

23 [14 to 26]

<  0.001

8 [6 to 10]

 Crystalloids (mL∙ kg−1)

17 [12 to 26]

14 [11 to 21]

20 [13 to 31]

<  0.001

5 [4 to 7]

 Colloids (mL∙ kg−1)

7 [3 to 9]

4 [0 to 7]

7 [6 to 12]

<  0.001

3 [2 to 6]

  1. Data are presented as median [25th–75th percentile] or % (n/N). For binary and continuous variables risk difference and median difference with 95% confidence intervals in square brackets are reported respectively
  2. Abbreviations: BMI Body mass index, ASA American Society of Anaesthesiologists, ARISCAT Assess Respiratory Risk in Surgical Patients in Catalonia risk index,14,15 Hb Haemoglobin, GI Gastrointestinal, HBP Hepatobiliopancreatic, SpO2 Peripheral oxygen saturation, CI Confidence interval, COPD Chronic Obstructive Pulmonary Disease, OSAS Obstructive sleep apnea sydnrome, TIVA Total Intravenous Anaesthesia
  3. aNeuromuscular disease affecting the respiratory system
  4. bThe same patient may have more than one surgical indication
  5. cUrgency of surgery is defined as elective: surgery that is scheduled in advance because it does not involve a medical emergency, urgent: surgery required within < 48 h, emergent: surgery performed when the patients’ life or well being are threatened
  6. dDuration of surgery is the time between skin incision and closure of the incision
  7. eDuration of anaesthesia is the time between start of induction and tracheal extubation or discharge from operation room if the mechanical ventilation is continued
  8. fDaytime surgery is defined as anaesthesia induction between 8:00 a.m. and 19:59 p.m.