Impact Of Peak Oxygen Pulse On Patients With Chronic Obstructive Pulmonary Disease

Figures & data

Table 1 Baseline Characteristics Of The Two Groups

	All (N = 79)	Group 1 (n = 37)	Group 2 (n = 42)	p-value
Age (years)	70 ± 9	71 ± 9	69 ± 9	0.304
Male/female (n)		30/7	38/4	0.331
BH (cm)	162 ± 8	161 ± 8	164 ± 7	0.120
BW (kg)	60 ± 11	59 ± 13	61 ± 10	0.375
BMI (kg/m^2)	23 ± 4	23 ± 4	24 ± 3	0.702
Hemoglobin (mg/dL)	14 ± 2	14 ± 2	14 ± 2	0.688
GOLD				<0.001
I	3 (4%)	3 (8%)	0 (0%)
II	30 (38%)	21 (57%)	9 (21%)
III	39 (49%)	13 (35%)	26 (62%)
IV	7 (9%)	0 (0%)	7 (17%)
ABCD assessment				0.562
A	7	4	3
B	57	27	30
C	1	1	0
D	14	5	9
Smoking				0.108
Non-smoker	10 (13%)	7 (19%)	3 (7%)
Current smoker	32 (41%)	11 (30%)	21 (50%)
Ex-smoker	37 (47%)	19 (51%)	18 (43%)
Pharmacologic Tx				0.688
Nil	1	0	1
SABD	2	1	1
LABA+ICS	27	14	13
LAMA	9	6	3
LABA+LAMA	10	4	6
LABA+LAMA+ICS	30	12	18
CV comorbidities
CHF	12	6	6	0.811
CAD	3	2	1	0.597
HTN	23	15	8	0.036
Arrhythmia	10	5	5	0.830
Valvular disease	2	1	1	1.000
Echocardiography
LVEF (%)	67 ± 12	66 ± 14	68 ± 10	0.398
Stroke volume (mL)	65 ± 22	64 ± 22	66 ± 22	0.659
TRPG (mmHg)	28 ± 12	30 ± 14	26 ± 10	0.055

Note: Data are presented as mean ± standard deviation or number (percentage).

Abbreviations: BH, body height; BW, body weight; BMI, body mass index; COPD, chronic obstructive pulmonary disease; Tx, treatment; SABD, short-acting bronchodilator; LABA, long-acting beta₂-agonist; ICS, inhaled corticosteroid; LAMA, long-acting antimuscarinic antagonist; CHF, congestive heart failure; CAD, coronary artery disease; CV, cardiovascular; LVEF, left ventricular ejection fraction; TRPG, tricuspid regurgitation pressure gradient; HTN, hypertension.

Table 2 Impact Of Peak Oxygen Pulse (O₂P) On Exercise Capacity

	All (N = 79)	Group 1 (n = 37)	Group 2 (n = 42)	p-value
Peak VO2 (mL/min)	908.6 ± 273.8	1060.8 ± 268.2	774.5 ± 200.5	<0.001
Peak VO2 (% predicted)	64.9 ± 17.2	78.9 ± 12.2	52.5 ± 9.8	<0.001
Peak WR (watt)	62.2 ± 26.7	75.1 ± 25.6	50.8 ± 22.2	<0.001
Peak WR (% predicted)	70.3 ± 28.2	89.4 ± 22.9	53.4 ± 20.7	<0.001

Note: Data are presented as mean ± standard deviation.

Abbreviations: VO₂, oxygen uptake; WR, work rate.

Table 3 Impact Of Peak Oxygen Pulse (O₂P) On Circulatory Parameters

	All (N = 79)	Group 1 (n = 37)	Group 2 (n = 42)	p-value
Peak O2P (mL/beat)	7.37 ± 2.03	8.69 ± 1.86	6.20 ± 1.36	<0.001
Peak O2P (% predicted)	78.8 ± 19.0	96.0 ± 10.4	63.6 ± 9.4	<0.001
AT (mL/min)	615.9 ± 139.4	667.7 ± 134.0	568.0 ± 128.1	0.001
AT (% predicted)	44.2 ± 10.0	50.4 ± 9.3	38.5 ± 6.8	<0.001
WE (mL/min/watt)	8.2 ± 1.9	8.7 ± 1.9	7.7 ± 1.7	0.015
MBP rest (mmHg)	89.5 ± 11.1	87.2 ± 11.8	91.4 ± 10.0	0.088
MBP peak (mmHg)	107.6 ± 15.1	107.5 ± 15.8	107.7 ± 14.7	0.953
HR rest (beats/min)	86.5 ± 12.9	85.1 ± 13.2	87.8 ± 12.6	0.363
HR peak (beats/min)	123.6 ± 16.6	122.4 ± 17.0	124.7 ± 16.4	0.532

Note: Data are presented as mean ± standard deviation.

Abbreviations: AT, anaerobic threshold; WE, work efficiency; MBP, mean blood pressure; HR, heart rate.

Table 4 Impact Of Peak Oxygen Pulse (O₂P) On Ventilatory Parameters

	All (N = 79)	Group 1 (n = 37)	Group 2 (n = 42)	p-value
FVC (L)	2.21 ± 0.69	2.25 ± 0.71	2.18 ± 0.67	0.650
FVC (% predicted)	80.0 ± 19.0	84.2 ± 19.0	76.3 ± 18.4	0.065
FEV1 (L/s)	1.04 ± 0.42	1.18 ± 0.47	0.91 ± 0.32	0.003
FEV1 (% predicted)	47.9 ± 16.0	56.3 ± 15.9	40.5 ± 12.0	<0.001
FEV1/FVC	0.47 ± 0.11	0.53 ± 0.09	0.42 ± 0.10	<0.001
MIP (cm H2O)	65.1 ± 26.1	64.8 ± 23.6	65.3 ± 28.4	0.934
MIP (% predicted)	65.8 ± 25.7	67.7 ± 25.4	64.1 ± 26.1	0.538
MEP (cm H2O)	109.6 ± 38.1	108.8 ± 27.7	110.3 ± 45.6	0.866
MEP (% predicted)	59.7 ± 20.6	61.7 ± 18.5	57.9 ± 22.3	0.412
VE rest (L/min)	12.1 ± 3.1	12.3 ± 3.1	11.9 ± 3.1	0.574
VE peak (L/min)	32.3 ± 10.3	36.2 ± 9.7	28.8 ± 9.6	0.001
RR rest (breath/min)	19.1 ± 4.6	19.4 ± 4.2	18.9 ± 5.0	0.654
RR peak (breath/min)	32.3 ± 7.4	34.0 ± 6.5	30.8 ± 7.8	0.056
VT rest (mL)	652.8 ± 159.4	650.7 ± 146.2	654.6 ± 171.9	0.913
VT peak (mL)	1020.0 ± 306.6	1091.9 ± 326.3	956.7 ± 276.8	0.05
VE/VCO2 at AT	37.0 ± 6.1	35.4 ± 6.4	38.4 ± 5.6	0.029
SpO2 rest (%)	95.9 ± 2.0	96.2 ± 1.9	95.7 ± 2.1	0.252
SpO2 peak (%)	92.9 ± 3.6	93.5 ± 3.3	92.4 ± 3.8	0.171
PETCO2 rest (mmHg)	35.2 ± 5.5	35.6 ± 5.6	35.0 ± 5.4	0.648
PETCO2 peak (mmHg)	41.0 ± 7.1	41.2 ± 7.9	40.8 ± 6.4	0.778

Note: Data are presented as mean ± standard deviation.

Abbreviations: FEV1, forced expiratory volume in one second; FVC, forced vital capacity; MIP, maximal inspiratory pressure; MEP, maximal expiratory pressure; VE, minute ventilation; RR, respiratory rate; V_T, tidal volume; VCO₂, carbon dioxide production; SpO₂, arterial oxygen hemoglobin saturation; PETCO₂, partial pressure of carbon dioxide at the end of exhaled breath.

Table 5 Impact Of Peak Oxygen Pulse (O₂P) On Dyspnea Score And Health-Related Quality Of Life

	All (N = 79)	Group 1 (n = 37)	Group 2 (n = 42)	p-value
Borg CR10, rest (points)	0.47 ± 0.67	0.32 ± 0.63	0.60 ± 0.69	0.073
Borg CR10, peak (points)	5.48 ± 1.66	5.49 ± 1.63	5.48 ± 1.70	0.978
SGRQ, total (points)	36.8 ± 18.6	31.9 ± 15.8	41.1 ± 19.9	0.029
SGRQ, symptom (points)	42.7 ± 22.7	36.8 ± 19.8	47.9 ± 24.0	0.029
SGRQ, activity (points)	51.9 ± 20.0	46.4 ± 18.0	56.6 ± 20.6	0.023
SGRQ, impact (points)	27.2 ± 22.2	23.2 ± 19.9	30.8 ± 23.6	0.129

Note: Data are presented as mean ± standard deviation.

Abbreviations: Borg CR10, Borg’s category-ratio 10 scale; SGRQ, Saint George’s Respiratory Questionnaire.

Table 6 Impact Of Peak Oxygen Pulse (O₂P) On The Number Of Hospitalizations And Emergency Room (ER) Visits In The Following Year After Enrollment

	All (N = 79)	Group 1 (n = 37)	Group 2 (n = 42)	p-value
Hospitalizations	0.41 ± 0.968	0.22± 0.886	0.57 ± 1.016	0.009^a
ER visits	0.57 ± 1.420	0.38 ±1.361	0.74 ± 1.466	0.112^a

Note: Data are presented as mean ± standard deviation.

Abbreviation: ER, emergency room.

Figure 1 The simple linear regression between peak oxygen pulse (O₂P) and anaerobic threshold (AT). The slant line is calculated using least square regression analysis. (p < 0.001; R² = 0.566; Pearson’s r = 0.756).

Figure 2 The simple linear regression between forced expiratory volume in one second (FEV1) and peak oxygen pulse (O₂P). The slant line is calculated using least square regression analysis. (p < 0.001; R² = 0.202; Pearson’s r = 0.461).