Noninvasive positive pressure ventilation in subjects with stable COPD: a randomized trial

Figures & data

Table 1 Comparison of baseline characteristics in cases and controls

Variable	NPPV (n=15)	Controls (n=12)
Age (years)^†	70 (66–73)	68 (65–78)
Sex (% male)	8 (53)	12 (100)*
BMI (kg/m^2)	24.8 (2.8)	24.8 (4.8)
Pack-years of smoking	59 (29)	61 (30)
FEV1 %pred	30.3 (7)	29.6 (7.4)
FVC %pred	68.8 (14.1)	59.4 (8)
NIF (cm H2O)	−48.9 (14.5)	−63.2 (23.9)
PaCO2 (mmHg)	42.4 (5.6)	41.9 (4.6)
PaO2 (mmHg)	65.1 (13.3)	73.9 (9.9)
6MWD (m)	284 (101)	321 (91)
CRQ score
Dyspnea	3.8 (1)	3.7 (1)
Fatigue	4.3 (1)	4.1 (1)
Emotional function	5.5 (0.7)	5.3 (1.1)
Mastery	5 (1.1)	5.3 (1.4)
Dyspnea
TDI-Function	1.9 (0.7)	1.5 (0.7)
TDI-Task	1.3 (0.5)	1.4 (0.7)
TDI-Effort	1.3 (0.5)	1.3 (0.5)
TDI total	4.5 (1.6)	4.2 (1.5)
PSQI	3.7 (3)	6.1 (3.2)

Notes: All results are expressed as the mean (standard deviation) except for ^†median (interquartile range).

* P<0.05.

Abbreviations: FEV₁, forced expiratory volume in the first second; %pred, percent predicted; FVC, forced vital capacity; NIF, negative inspiratory force; NPPV, noninvasive positive pressure ventilation; PaCO₂, partial pressure of carbon dioxide in arterial blood; PaO₂, partial pressure of oxygen in arterial blood; 6MWD, six-minute walk distance; CRQ, Chronic Respiratory Disease Questionnaire; TDI, Transitional Dyspnea Index at baseline; PSQI, Pittsburgh Sleep Quality Index; BMI, body mass index.

Table 2 Comparison of outcomes between intervention and control arms at 6 months

	NPPV (n=15)			Controls (n=12)			P-value
	Baseline	6 months	Difference	Baseline	6 months	Difference
FEV1 %pred	30.3 (7)	31.2 (11.9)	0.9	29.6 (7.4)	31 (7.8)	1.4	0.84
FVC %pred	68.8 (14.1)	71.9 (16.7)	3.1	59.4 (8)	60.8 (30.2)	1.3	0.74
NIF (cm H2O)	−48.9 (14.5)	−55.9 (20.3)	7	−63.2 (23.9)	−63 (21.9)	0.3	0.14
PaCO2 (mmHg)	42.4 (5.6)	44.3 (8.5)	1.9	41.9 (4.6)	42.9 (4.5)	1	0.68
PaO2 (mmHg)*	65.1 (13.3)	67.2 (14.4)	2.1	73.9 (9.9)	66.8 (9.9)	−7.2	0.02
6MWD (m)	284 (101)	280 (142)	−14	321 (91)	304 (129)	−17	0.73
CRQ score
Dyspnea	3.8 (1)	4.1 (1.2)	0.3	3.7 (1)	3.4 (0.9)	−0.3	0.26
Fatigue	4.3 (1)	4.6 (1.3)	0.4	4.1 (1)	4.2 (0.9)	0	0.36
Emotional function	5.5 (0.7)	5.6 (1.1)	0.2	5.3 (1.1)	5.3 (1.3)	0	0.46
Mastery*	5 (1.1)	5.6 (1)	0.6	5.3 (1.4)	5.2 (1.2)	−0.1	0.04
Dyspnea
TDI-Function	1.9 (0.7)	0 (0.8)	−1.9	1.5 (0.7)	−0.2 (0.7)	−1.7	0.63
TDI-Task*	1.3 (0.5)	0.5 (0.7)	−0.8	1.4 (0.7)	−0.3 (0.7)	−1.8	0.03
TDI-Effort	1.3 (0.5)	0.5 (0.7)	−0.8	1.3 (0.5)	−0.3 (0.7)	−1.6	0.06
TDI total	4.5 (1.6)	0.9 (2)	−3.4	4.2 (1.5)	−0.5 (2.3)	−4.7	0.35
PSQI	3.7 (3)	3.4 (2.3)	0.2	6.1 (3.3)	5.7 (3.2)	0.4	0.77

Notes: All results are expressed as the mean (standard deviation).

* P<0.05.

Abbreviations: FEV₁, forced expiratory volume in the first second; %pred, percent predicted; FVC, forced vital capacity; NIF, negative inspiratory force; PaCO₂, partial pressure of carbon dioxide in arterial blood; PaO₂, partial pressure of oxygen in arterial blood; 6MWD, six-minute walk distance; CRQ, Chronic Respiratory disease Questionnaire; TDI, Transitional Dyspnea Index at baseline; PSQI, Pittsburgh Sleep Quality Index.

Figure 1 Randomization and follow-up of patients in intervention and control arms.

Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in the first second; FVC, forced vital capacity; PaCO₂, partial pressure of carbon dioxide in arterial blood; NPPV, noninvasive positive pressure ventilation.

Figure 2 Change in dyspnea measured by TDI and quality of life (CRQ-Mastery domain) over time in intervention and control arms. Dots represent control arm; squares represent intervention arm.

Notes: *P<0.05 and **P<0.01.
Abbreviations: TDI, Transitional Dyspnea Index; CRQ, Chronic Respiratory Disease Questionnaire; NPPV, noninvasive positive pressure ventilation.

Table 3 Compliance with noninvasive positive pressure ventilation

Days used	80.6 (69.1)
% days used	42 (36)
Number of hours used (average per night), patient-reported	3.9 (3.4)
Number of hours used (average per night), machine-reported	3.1 (3.3)
% use greater than 4 hours per night	40%
Initial compliance (usage >4 hours/night in first week)	8 (53%)
Number indicating willingness to continue using device (%)	8 (53)

Note: All numbers are expressed as the mean (standard deviation).

Table 4 Side effects

	NPPV (n=15)	Controls (n=12)
Dryness of eyes	1 (1)	1 (0)
Sinus congestion	5 (2)	0
Nose bleeds	1 (0)	1 (0)
Discomfort	5 (3)	0
Skin breaks	1 (1)	0

Notes: All numbers expressed as total number experiencing symptoms any time during course of study; numbers in brackets indicate those who had persistent symptoms at 6 months.

Abbreviation: NPPV, noninvasive positive pressure ventilation.

Figure 3 Correlation between change in CRQ-Mastery domain and average numbers of hours of use of noninvasive positive pressure ventilation.

Abbreviation: CRQ, Chronic Respiratory Disease Questionnaire.

Table 5 Comparison of randomized studies of domiciliary NPPV in chronic stable COPD without hypercapnea

	n	Duration of follow-up	NPPV intensity (cm H2O)	PaCO2 (mmHg)	Quality of life	Dyspnea	Sleep	Exacerbations	Survival
Garrod et al^Citation11 (versus rehabilitation)	Cases (n=23) Controls (n=22)	8 weeks	16/4	44.2	CRQ improved	CRQ dyspnea = NS	–	–	–
Casanova et al^Citation8 (versus domiciliary O2)	20 (24)	One year	12/4	50.7	Improvement in psychomotor coordination	Borg score improved	–	NS	NS
Lin et al^Citation23	12 (crossover)	2 weeks	12/–	50.5	–	–	Sleep worsened	–	–
Strumpf et al^Citation21	7 (crossover)	3 months	15/–	50	–	NS	NS	–	–
Current study	15 (12)	6 months	15/5	42	CRQ-Mastery improved	TDI-Task improved	NS	NS	–

Abbreviations: COPD, chronic obstructive pulmonary disease; NPPV, noninvasive positive pressure ventilation; PaCO₂, partial pressure of carbon dioxide in arterial blood; CRQ, Chronic Respiratory Disease Questionnaire; O₂, oxygen; TDI, Transitional Dyspnea Index; NS, no significant change.

Table S1 Comparison between groups at each time point and over all time points (repeated-measures analysis of variance)

	Baseline		6 weeks		3 months		6 months		P-value
	NPPV	Controls	NPPV	Controls	NPPV	Controls	NPPV	Controls
FEV1 %pred	30.3 (7)	29.6 (7.4)			32.2 (11.8)	31.5 (6.4)	31.2 (11.9)	31 (7.8)	0.81
FVC %pred	68.8 (14.1)	59.4 (8)			74.2 (19.2)	62.8 (8.8)	71.9 (16.7)	60.8 (30.2)	0.97
NIF (cm H2O)	−48.9 (14.5)	−63.2 (23.9)			−59.7 (24.1)	−64.5 (23.9)	−55.9 (20.3)	−63 (21.9)	0.16
PaCO2 (mmHg)	42.4 (5.6)	41.9 (4.6)			44.1 (7)	42.7 (4)	44.3 (8.5)	42.9 (4.5)	0.92
PaO2 (mmHg)	65.1 (13.3)	73.9 (9.9)			62.1 (15.2)	66.7 (10.5)	67.2 (14.4)	66.8 (9.9)	0.12
6MWD (m)	284 (101)	321 (91)	312 (110)	320 (94)	295 (101)	335 (90)	280 (142)	304 (129)	0.50
CRQ score
Dyspnea	3.8 (1)	3.7 (1)	4.1 (0.9)	3.7 (1.4)	3.9 (0.8)	3.6 (1.3)	4.1 (1.2)	3.4 (0.9)	0.64
Fatigue	4.3 (1)	4.1 (1)	4.5 (0.9)	3.9 (1.2)	4.4 (1)	4.1 (1.1)	4.6 (1.3)	4.2 (0.9)	0.39
Emotional function	5.5 (0.7)	5.3 (1.1)	5.6 (0.7)	5.1 (1.1)	5.5 (0.9)	5.2 (1.3)	5.6 (1.1)	5.3 (1.3)	0.37
Mastery*	5 (1.1)	5.3 (1.4)	5.5 (1)	5 (1.6)	5.6 (1)	5.2 (1.2)	5.6 (1)	5.2 (1.2)	0.047
Dyspnea
TDI-Function	1.9 (0.7)	1.5 (0.7)	0.6 (0.9)*	−0.3 (1.1)	0.4 (0.8)*	−0.2 (0.4)	0 (0.8)	−0.2 (0.7)	0.31
TDI-Task	1.3 (0.5)	1.4 (0.7)	0.3 (0.5)	−0.3 (0.6)	0.4 (0.5)*	−0.3 (0.9)	0.5 (0.7)*	−0.3 (0.7)	0.07
TDI-Effort	1.3 (0.5)	1.3 (0.5)	0.3 (0.5)*	−0.3 (0.6)	0.4 (0.5)*	−0.1 (0.7)	0.5 (0.7)*	−0.3 (0.7)	0.13
TDI total	4.5 (1.6)	4.2 (1.5)	1.3 (1.9)**	−0.8 (1.9)	1.3 (1.7)*	−0.3 (0.9)	0.9 (2)	−0.5 (2.3)	0.28

Notes: All results expressed as the mean (standard deviation).

* P<0.05 and

** P<0.01.

Abbreviations: FEV₁, forced expiratory volume in the first second; %pred, percent predicted; FVC, forced vital capacity; NIF, negative inspiratory force; NPPV, noninvasive positive pressure ventilation; PaCO₂, partial pressure of carbon dioxide in arterial blood; PaO₂, partial pressure of oxygen in arterial blood; 6MWD, six-minute walk distance; CRQ, Chronic respiratory Disease Questionnaire; TDI, Transitional Dyspnea Index at baseline.

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