J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://www.jocmr.org

Original Article

Volume 14, Number 9, September 2022, pages 341-347

Severe Obesity and Prolonged Postoperative Mechanical Ventilation in Elderly Vascular Surgery Patients

**Table 1.** Characteristics of the Study Population
Characteristics	Normal weight, BMI ≤ 25 kg/m², n (%)	Severe obesity, BMI > 40 kg/m², n (%)	Overall, n (%)	Standardized difference in proportion
N: number; BMI: body mass index; CHF: congestive heart failure; COPD: chronic obstructive pulmonary disease; ASA: American Society of Anesthesiology.
Study population	31,700 (90.7)	3,236 (9.3)	34,936 (100.0)
Age (years)
65 - 74	14,676 (46.3)	2,302 (71.1)	16,978 (48.6)	0.52
75 - 84	12,066 (38.1)	846 (26.1)	12,912 (37.0)	0.26
≥ 85	4,958 (15.6)	88 (2.7)	5,046 (14.4)	0.46
Race
White	22,688 (71.6)	2,449 (75.7)	25,137 (72.0)	0.09
African American	3,466 (10.9)	373 (11.5)	3,839 (11.0)	0.02
Other	1,031 (3.3)	29 (0.9)	1,060 (3.0)	0.17
Unknown	4,515 (14.2)	385 (11.9)	4,900 (14.0)	0.07
Female sex	12,355 (39.0)	1,583 (48.9)	13,938 (39.9)	0.20
Smoking within one year of surgery	10,611 (33.5)	462 (14.3)	11,073 (31.7)	0.46
Emergency case	2,908 (9.2)	277 (8.6)	3,185 (9.1)	0.02
ASA ≥ 3	30,356 (96.2)	3,171 (98.4)	33,527 (96.4)	0.13
Diabetes	8,138 (25.7)	1,768 (54.6)	9,906 (28.4)	0.62
On dialysis prior to surgery	1,762 (5.6)	213 (6.6)	1,975 (5.7)	0.04
Dyspnea	3,934 (12.4)	749 (23.1)	4,683 (13.4)	0.28
Functional dependency	3,502 (11.1)	332 (10.3)	3,834 (11.0)	0.03
CHF 30 days before surgery	1,145 (3.6)	198 (6.1)	1,343 (3.8)	0.12
History of severe COPD	5,102 (16.1)	560 (17.3)	5,662 (16.2)	0.03
Hypertension requiring medication	25,236 (79.6)	2,889 (89.3)	28,125 (80.5)	0.27
Steroid use for chronic condition	1,575 (5.0)	134 (4.1)	1,709 (4.9)	0.04
Transfusion 72 h before surgery	826 (2.6)	73 (2.3)	899 (2.6)	0.02
Ascites	64 (0.2)	3 (0.1)	67 (0.2)	0.03
Acute renal failure	343 (1.1)	59 (1.8)	402 (1.2)	0.06
Operating time	119 (79 - 182)	115 (78 - 174)	118 (79 - 181)	0.03
Transfer status
Acute care inpatient	1,186 (3.7)	135 (4.2)	1,321 (3.8)	0.02
From home	27,482 (86.7)	2,826 (87.4)	30,308 (86.8)	0.02
Nursing home/chronic care	1,358 (4.3)	112 (3.5)	1,470 (4.2)	0.04
Outside emergency room	1,445 (4.6)	147 (4.5)	1,592 (4.6)	0.00
Other	209 (0.7)	14 (0.4)	223 (0.6)	0.03
Year of operation
2015	8,057 (25.4)	756 (23.4)	8,813 (25.2)	0.05
2016	8,296 (26.2)	897 (27.7)	9,193 (26.3)	0.03
2017	8,330 (26.3)	846 (26.1)	9,176 (26.3)	0.00
2018	7,017 (22.1)	737 (22.8)	7,754 (22.2)	0.02

Table 1. Characteristics of the Study Population

Characteristics

Normal weight, BMI ≤ 25 kg/m², n (%)

Severe obesity, BMI > 40 kg/m², n (%)

Overall, n (%)

Standardized difference in proportion

N: number; BMI: body mass index; CHF: congestive heart failure; COPD: chronic obstructive pulmonary disease; ASA: American Society of Anesthesiology.

Study population

31,700 (90.7)

3,236 (9.3)

34,936 (100.0)

Age (years)

65 - 74

14,676 (46.3)

2,302 (71.1)

16,978 (48.6)

0.52

75 - 84

12,066 (38.1)

846 (26.1)

12,912 (37.0)

0.26

≥ 85

4,958 (15.6)

88 (2.7)

5,046 (14.4)

0.46

Race

White

22,688 (71.6)

2,449 (75.7)

25,137 (72.0)

0.09

African American

3,466 (10.9)

373 (11.5)

3,839 (11.0)

0.02

Other

1,031 (3.3)

29 (0.9)

1,060 (3.0)

0.17

Unknown

4,515 (14.2)

385 (11.9)

4,900 (14.0)

0.07

Female sex

12,355 (39.0)

1,583 (48.9)

13,938 (39.9)

0.20

Smoking within one year of surgery

10,611 (33.5)

462 (14.3)

11,073 (31.7)

0.46

Emergency case

2,908 (9.2)

277 (8.6)

3,185 (9.1)

0.02

ASA ≥ 3

30,356 (96.2)

3,171 (98.4)

33,527 (96.4)

0.13

Diabetes

8,138 (25.7)

1,768 (54.6)

9,906 (28.4)

0.62

On dialysis prior to surgery

1,762 (5.6)

213 (6.6)

1,975 (5.7)

0.04

Dyspnea

3,934 (12.4)

749 (23.1)

4,683 (13.4)

0.28

Functional dependency

3,502 (11.1)

332 (10.3)

3,834 (11.0)

0.03

CHF 30 days before surgery

1,145 (3.6)

198 (6.1)

1,343 (3.8)

0.12

History of severe COPD

5,102 (16.1)

560 (17.3)

5,662 (16.2)

0.03

Hypertension requiring medication

25,236 (79.6)

2,889 (89.3)

28,125 (80.5)

0.27

Steroid use for chronic condition

1,575 (5.0)

134 (4.1)

1,709 (4.9)

0.04

Transfusion 72 h before surgery

826 (2.6)

73 (2.3)

899 (2.6)

0.02

Ascites

64 (0.2)

3 (0.1)

67 (0.2)

0.03

Acute renal failure

343 (1.1)

59 (1.8)

402 (1.2)

0.06

Operating time

119 (79 - 182)

115 (78 - 174)

118 (79 - 181)

0.03

Transfer status

Acute care inpatient

1,186 (3.7)

135 (4.2)

1,321 (3.8)

0.02

From home

27,482 (86.7)

2,826 (87.4)

30,308 (86.8)

0.02

Nursing home/chronic care

1,358 (4.3)

112 (3.5)

1,470 (4.2)

0.04

Outside emergency room

1,445 (4.6)

147 (4.5)

1,592 (4.6)

0.00

Other

209 (0.7)

14 (0.4)

223 (0.6)

0.03

Year of operation

2015

8,057 (25.4)

756 (23.4)

8,813 (25.2)

0.05

2016

8,296 (26.2)

897 (27.7)

9,193 (26.3)

0.03

2017

8,330 (26.3)

846 (26.1)

9,176 (26.3)

0.00

2018

7,017 (22.1)

737 (22.8)

7,754 (22.2)

0.02

**Table 2.** Severe Obesity and PPMV
Outcome measures	Obesity status	Number of events, n (%)^a	Unadjusted analysis	Adjusted analysis^b
^aPercentages are for rows. ^bAnalyses were adjusted for gender, body mass index, current smoking status, emergent case status, American Society of Anesthesiologists physical classification, diabetes (noninsulin-dependent or insulin-dependent diabetes mellitus), dyspnea (at rest or moderate exertion), functional health status within 30 days of surgery, history of chronic heart failure within 30 days of surgery, history of chronic obstructive pulmonary disease within 30 days of surgery, hypertension, bleeding disorder, corticosteroid use for a chronic condition, and operating time. N: number of events; OR: odds ratio; CI: confidence interval; BMI: body mass index; PPMV: prolonged postoperative mechanical ventilation.
Requirement for PPMV	Normal weight, BMI ≤ 25 kg/m²	624/31,700 (2.0)
	Severe obesity, BMI > 40 kg/m²	92/3,236 (2.8)	1.46 (1.17 - 1.82)	0.001	1.56 (1.22 - 1.99)	0.001
Extended length of stay	Normal weight, BMI ≤ 25 kg/m²	8,073 (25.5)
	Severe obesity, BMI > 40 kg/m²	875 (27.0)	1.08 (1.00 - 1.18)	0.051	0.95 (0.86 - 1.04)	0.254

Table 2. Severe Obesity and PPMV

Outcome measures

Obesity status

Number of events, n (%)^a

Unadjusted analysis

Adjusted analysis^b

OR (95% CI)

P value

OR (95% CI)

P value

^aPercentages are for rows. ^bAnalyses were adjusted for gender, body mass index, current smoking status, emergent case status, American Society of Anesthesiologists physical classification, diabetes (noninsulin-dependent or insulin-dependent diabetes mellitus), dyspnea (at rest or moderate exertion), functional health status within 30 days of surgery, history of chronic heart failure within 30 days of surgery, history of chronic obstructive pulmonary disease within 30 days of surgery, hypertension, bleeding disorder, corticosteroid use for a chronic condition, and operating time. N: number of events; OR: odds ratio; CI: confidence interval; BMI: body mass index; PPMV: prolonged postoperative mechanical ventilation.

Requirement for PPMV

Normal weight, BMI ≤ 25 kg/m²

624/31,700 (2.0)

Severe obesity, BMI > 40 kg/m²

92/3,236 (2.8)

1.46 (1.17 - 1.82)

0.001

1.56 (1.22 - 1.99)

0.001

Extended length of stay

Normal weight, BMI ≤ 25 kg/m²

8,073 (25.5)

Severe obesity, BMI > 40 kg/m²

875 (27.0)

1.08 (1.00 - 1.18)

0.051

0.95 (0.86 - 1.04)

0.254

**Table 3.** PPMV and Mortality
Obesity status	Requirement for PPMV	Mortality/n (%)^a	Unadjusted analysis	Adjusted analysis^b
^aPercentages are for rows. ^bAnalyses were adjusted for gender, body mass index, current smoking status, emergent case status, American Society of Anesthesiologists physical classification, diabetes (noninsulin-dependent or insulin-dependent diabetes mellitus), dyspnea (at rest or moderate exertion), functional health status within 30 days of surgery, history of chronic heart failure within 30 days of surgery, history of chronic obstructive pulmonary disease within 30 days of surgery , hypertension, bleeding disorder, corticosteroid use for a chronic condition, and operating time. N: number of events; OR: odds ratio; CI: confidence interval; BMI: body mass index; PPMV: prolonged postoperative mechanical ventilation.
Normal weight, BMI ≤ 25 kg/m²	No	819/31,076 (2.64)
	Yes	247/624 (39.6)	24.20 (20.30 - 28.83)	< 0.001	23.10 (18.96 - 28.16)	< 0.001
Severe obesity, BMI > 40 kg/m²	No	50/3,144 (1.6)
	Yes	28/92 (30.4)	27.07 (16.02 - 45.75)	< 0.001	25.26 (13.44 - 47.5)	< 0.001

Table 3. PPMV and Mortality

Obesity status

Requirement for PPMV

Mortality/n (%)^a

Unadjusted analysis

Adjusted analysis^b

OR (95% CI)

P value

OR (95% CI)

P value

^aPercentages are for rows. ^bAnalyses were adjusted for gender, body mass index, current smoking status, emergent case status, American Society of Anesthesiologists physical classification, diabetes (noninsulin-dependent or insulin-dependent diabetes mellitus), dyspnea (at rest or moderate exertion), functional health status within 30 days of surgery, history of chronic heart failure within 30 days of surgery, history of chronic obstructive pulmonary disease within 30 days of surgery , hypertension, bleeding disorder, corticosteroid use for a chronic condition, and operating time. N: number of events; OR: odds ratio; CI: confidence interval; BMI: body mass index; PPMV: prolonged postoperative mechanical ventilation.

Normal weight, BMI ≤ 25 kg/m²

819/31,076 (2.64)

Yes

247/624 (39.6)

24.20 (20.30 - 28.83)

< 0.001

23.10 (18.96 - 28.16)

< 0.001

Severe obesity, BMI > 40 kg/m²

50/3,144 (1.6)

Yes

28/92 (30.4)

27.07 (16.02 - 45.75)

< 0.001

25.26 (13.44 - 47.5)

< 0.001