Effectiveness of a perioperative pulmonary rehabilitation program following coronary artery bypass graft surgery in patients with and without COPD

Figures & data

Figure 1 Overview of patient selection.

Abbreviations: CABG, coronary artery bypass graft; PRP, pulmonary rehabilitation program.

Table 1 Patient characteristics

Variables	COPD group (n=40)	Non-COPD group (n=38)	P-value
Age			0.406a
≤65	20 (50.0%)	21 (55.3%)
≥66	20 (50.0%)	17 (44.7%)
Gender			0.026a,*
Male	37 (92.5%)	28 (73.7%)
Female	3 (7.5%)	10 (26.3%)
Body mass index (kg/m^2)			0.406a
≤24	20 (50.0%)	17 (44.7%)
≥25	20 (50.0%)	21 (55.3%)
Smoking index (pack-years)	314.63 (±567.25)	122.16 (±347.14)	0.189b
APACHE II score			0.449a
≤13	31 (77.5%)	28 (73.7%)
≥14	9 (22.5%)	10 (26.3%)
ASA physical status			0.069a
≤3	28 (70.0%)	34 (89.5%)
≥4	12 (30.0%)	4 (10.5%)
Comorbidities			0.188a
≤1	16 (40.0%)	20 (54.1%)
≥2	24 (60.0%)	18 (45.9%)
Medical therapy			0.558a
Aspirin	27 (67.5%)	20 (52.6%)
Calcium blocker	2 (5.0%)	4 (10.5%)
Beta-blocker	5 (12.5%)	7 (18.4%)
Heparin	6 (15.0%)	7 (18.4%)
Ejection fraction			0.285a
≤30	4 (10.0%)	7 (18.4%)
≥30	36 (90.0%)	31 (81.6%)
Coronary artery disease			0.790a
≤Two-vessel CAD	10 (25.0%)	8 (21.1%)
≥Three-vessel CAD	30 (75.0%)	30 (78.9%)
Surgery type			0.679a
Isolated CABG	29 (72.5%)	26 (68.4%)
CABG+aortic valve	6 (15.0%)	4 (10.5%)
CABG+mitral valve	3 (7.5%)	6 (15.8%)
CABG+ventricular septal repair	2 (5.0%)	2 (5.3%)
Basal spirometry
FVC (L)	2.37 (±0.71)	2.68 (±0.75)	0.093b
FEV1 (L)	1.78 (±0.53)	2.22 (±0.59)	0.000b,**
FEV1% predicted	69.17 (±15.73)	91.08 (±13.35)	0.000b,**
FEV1/FVC%	67.39 (±6.06)	78.51 (±8.88)	0.000b,**
FEF25–75%	50.40 (±20.93)	69.19 (±14.46)	0.000b,**

Notes: Comorbidities included diabetes mellitus, chronic kidney disease and hypertension.

a Chi-square test.

b Mann–Whitney U-test.

* P<0.05.

** P<0.01.

Abbreviations: APACHE II, Acute Physiology and Chronic Health Evaluation II; ASA, American Society of Anesthesiologists; CAD, coronary artery disease; CABG, coronary artery bypass graft; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; FEF_25–75, forced expiratory flow between 25% and 75%.

Table 2 Effect of pulmonary rehabilitation intervention on respiratory muscle strength and breathlessness

Variables	COPD group (n=40)				Non-COPD group (n=38)
	Extubation Day 1	Extubation Day 14	Change (%)	P-valuea	Extubation Day 1	Extubation Day 14	Change (%)	P-valuea	P-valueb
Muscle strength
MIP (cmH2O)	−34.52 (±14.83)	−43.25 (±21.53)	25.3 (±44.0)	0.001a,**	−34.67 (±13.84)	−48.18 (±23.96)	39.0 (±59.3)	0.000a,**	0.335b
MEP (cmH2O)	32.15 (±13.16)	46.05 (±21.92)	43.2 (±70.2)	0.000a,**	37.78 (±18.65)	45.72 (±21.57)	21.0 (±38.7)	0.003a,**	0.379b
Breathlessness
RR (beats/minute)	20.65 (±3.44)	17.02 (±1.92)	17.5 (±19.1)	0.000a,**	20.65 (±4.21)	17.34 (±2.22)	16.0 (±23.4)	0.000a,**	0.814b
Borg Scale	3.10 (±0.67)	2.75 (±1.35)	11.3 (±3.9)	0.184a	3.28 (±0.76)	2.94 (±1.29)	10.4 (±46.3)	0.182a	0.935b

Notes:

a Wilcoxon signed-rank test.

b Mann–Whitney U-test.

** P<0.01.

Abbreviations: MIP, maximal inspiratory pressure; MEP, maximal expiratory pressure; RR, respiratory rate.

Table 3 Effect of pulmonary rehabilitation intervention on pulmonary function

Variables	COPD group (n=40)				Non-COPD group (n=38)
	Extubation Day 1	Extubation Day 14	Change (%)	P-valuea	Extubation Day 1	Extubation Day 14	Change (%)	P-valuea	P-valueb
FVC (L)	0.85 (±0.29)	1.25 (±0.36)	47.1 (±44.7)	0.000a,**	1.11 (±0.80)	1.36 (±0.65)	22.5 (±74.8)	0.009a,*	0.186b
FEV1 (L)	0.75 (±0.32)	1.08 (±0.35)	42.7 (±57.3)	0.000a,**	0.96 (±0.70)	1.09 (±0.60)	13.5 (±92.7)	0.037a,*	0.310b
FEV1/FVC (%)	80.30 (±14.69)	84.92 (±10.48)	5.8 (±20.4)	0.112a	82.50 (±20.86)	87.07 (±14.41)	5.5 (±25.3)	0.961a	0.238b
Peak flow (L)	0.99 (±0.57)	1.79 (±0.80)	80.8 (±82.8)	0.000a,**	1.49 (±0.86)	1.65 (±1.08)	10.1 (±81.2)	0.265a	0.000b,**
FEF25–75 (L)	0.68 (±0.37)	1.15 (±0.53)	67.6 (±64.7)	0.000a,**	1.03 (±0.74)	1.26 (±0.80)	22.3 (±104.9)	0.037a,*	0.043b,*

Notes:

a Wilcoxon signed-rank test.

b Mann–Whitney U-test.

* P<0.05.

** P<0.01.

Abbreviations: FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; FEF_25–75, forced expiratory flow between 25% and 75%.

Table 4 Postoperative outcomes in patients with and without COPD

Variables	COPD group (n=40)	Non-COPD group (n=38)	P-value
Chest tube (hours)	70.24 (±75.20)	14.27 (±50.74)	0.000a,**
Pericardial drain (hours)	163.90 (±153.10)	142.66 (±95.81)	0.750a
Ventilator time (hours)	33.00 (±92.10)	10.52 (±8.98)	0.141a
ICU time (hours)	103.07 (±56.78)	84.08 (±62.78)	0.088a
O2 use (days)	11.44 (±3.87)	11.26 (±4.76)	0.645a
Hospital stay (days)	23.37 (±11.10)	19.80 (±7.01)	0.233a
30-Day mortality			0.727b
No	39 (97.6%)	37 (97.3%)
Yes	1 (2.4%)	1 (2.7%)
Pulmonary complication
Pneumonia			0.604b
Yes	7 (17.5%)	8 (21.0%)
No	33 (82.5%)	30 (79.0%)
Emphysema			0.116b
Yes	4 (10.1%)	3 (7.8%)
No	36 (89.9%)	35 (92.29%)
Atelectasis			0.549b
Yes	13 (32.5%)	12 (31.4%)
No	27 (67.5%)	26 (68.6%)
Respiratory failure			0.388b
Yes	4 (9.8%)	2 (5.4%)
No	36 (90.2%)	36 (94.6%)

Notes:

a Mann–Whitney U-test.

b Chi-square test.

** P<0.01.

Figure 2 FVC, FEV₁, peak flow and FEF_25–75 on postoperative Days 1 and 14.

Note: PRP was significantly more effective in improving pulmonary function especially peak flow and FEF_25–75 in patients with COPD (*P<0.05, **P<0.01).
Abbreviations: FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; FEF_25–75, forced expiratory flow between 25% and 75%; PRP, pulmonary rehabilitation program.