High pressure versus high intensity noninvasive ventilation in stable hypercapnic chronic obstructive pulmonary disease: a randomized crossover trial

Figures & data

Figure 1 Consort recruitment and retention diagram.

Abbreviations: PCV, pressure-controlled (high-intensity) ventilation; PSV, pressure support (high pressure) ventilation; NIV, noninvasive ventilation.

Table 1 Respiratory and ventilator parameters following 6 weeks of high-pressure and high-intensity noninvasive ventilation

	High pressure NIV (PSV)	High intensity NIV (PCV)	Mean difference (95% CI)	P value
Mean nightly use (hours:minutes)	6:37 ± 1:45	6:33 ± 2:14	0:04 (−0:45 to 0:53)	0.851
pH	7.38 ± 0.01	7.38 ± 0.02	0.00 (−0.01 to 0.01)	0.818
PaCO2 (kPa)	7.2 ± 0.8	7.0 ± 0.8	0.3 (−0.2 to 0.7)	0.190
PaO2 (kPa)	7.9 ± 1.5	8.2 ± 1.3	−0.3 (−0.7 to 0.03)	0.070
Serum bicarbonate (mmol/L)	31 ± 4	30 ± 4	1 (−0.1 to 2.1)	0.071
Overnight mean tcCO2 (kPa)	6.5 ± 1.2	6.5 ± 1.3	−0.1 (−0.9 to 0.9)	0.985
Patient triggering rate (%)	90 ± 9	25 ± 11	65 (51 to 79)	<0.001
Bf (bpm) on ventilator	14 ± 3	16 ± 2	−2.6 (−1.4 to −3.7)	0.002

Abbreviations: Bf, breathing frequency; CI, confidence interval; PaO₂, arterial partial pressure of oxygen; PaCO₂, arterial partial pressure of carbon dioxide; NIV, noninvasive ventilation; PSV, pressure support ventilation; PCV, pressure-controlled ventilation; tcCO₂, transcutaneous carbon dioxide.

Table 2 Sleep actigraphy following 6 weeks of high-pressure and high-intensity noninvasive ventilation

	High-pressure NIV (PSV)	High-intensity NIV (PCV)	Mean difference (95% CI)	P value
Actual sleep time (min)	345 ± 91	329 ± 120	16 (−49 to 82)	0.571
Actual wake time (min)	69 ± 35	83 ± 43	−14 (−40 to 11)	0.225
Sleep efficiency (%)	77 ± 12	73 ± 18	4 (−8 to 16)	0.484
Sleep latency (min)	20 ± 16	21 ± 16	−1 (−18 to 15)	0.835

Abbreviations: CI, confidence interval; PSV, pressure support ventilation; PCV, pressure controlled ventilation; NIV, noninvasive ventilation.

Table 3 Self-reported sleep comfort and sleep quality evaluated following 6 weeks of high-pressure and high-intensity noninvasive ventilation

	High-pressure NIV (PSV)	High-intensity NIV (PCV)	Mean difference	P value (95% CI)
Sleep comfort VAS (mm)	57 ± 29	58 ± 29	−1 (−40 to 37)	0.944
Sleep quality (0–5 scale)	3.3 ± 0.3	3.2 ± 0.6	0.1 (−0.3 to 0.7)	0.638

Notes: Sleep comfort VAS: 0–100 mm (0, least comfortable; 100, most comfortable). Sleep quality: 0 to 5 (0, least quality; 5, best quality).

Abbreviations: CI, confidence interval; VAS, visual analog scale; PSV, pressure support ventilation; PCV, pressure-controlled ventilation; NIV, noninvasive ventilation.

Table 4 Severe Respiratory Insufficiency questionnaire following 6 weeks of high-pressure and high-intensity noninvasive ventilation

	High pressure NIV (PSV)	High intensity NIV (PCV)	Mean difference (95% CI)	P value
Respiratory	69 ± 16	57 ± 11	12 (3 to 21)	0.017
Physical	57 ± 27	60 ± 29	−3 (−19 to 13)	0.668
Attendant symptoms and sleep	56 ± 10	51 ± 11	5 (−1 to 11)	0.070
Social relationships	70 ± 14	76 ± 12	−6 (−19 to 7)	0.297
Anxiety	74 ± 22	78 ± 23	−4 (−18 to 10)	0.557
Psychological well-being	72 ± 18	70 ± 24	2 (−11 to 16)	0.679
Social functioning	72 ± 22	70 ± 24	2 (−2 to 7)	0.283
Summary scale	67 ± 12	66 ± 16	1 (−4 to 7)	0.571

Abbreviations: CI, confidence interval; PSV, pressure support ventilation; PCV, pressure controlled ventilation; NIV, noninvasive ventilation.

Figure E1 Ventilator setup protocol used at initiation of ventilation in either high-intensity or high-pressure arms.

Abbreviations: EPAP, expiratory positive airway pressure; IPAP, inspiratory positive airway pressure; NIV; noninvasive ventilation.

Figure E2 Individual datum points for mean nightly ventilator usage during each 6-week trial period of high-intensity or high-pressure noninvasive ventilation.

Note: Data downloaded from ventilators using Bespoke^® software (B&D ElectroMedical, Warwickshire, UK).

Figure E3 Individual datum points for arterial partial pressure of carbon dioxide (PaCO₂) following a 6-week trial period in both the high-intensity and high-pressure arms.

Figure E4 Individual datum points for health-related quality of life as measured by the Severe Respiratory Insufficiency questionnaire summary scale (A) and Severe Respiratory Insufficiency respiratory complaints domain (B) following 6-week trial period in the high-intensity or high-pressure arms.

Abbreviations: SRI, Severe Respiratory Insufficiecy.

Table E1 Individual baseline characteristics for all recruited patients

Age (years)	Gender	FEV1 (l/%)	FVC (l/%)	FEV1/ FVC (%)	PaCO2 (kPa)	PaO2 (kPa)	Starting mode	Outcome	IPAP	EPAP	BUR (PCV)	BUR (PSV)
71	M	0.55/20	1.23/35	45	12.2	8.6	PSV	Completed	28	3	16	6
67	M	1.49/50	2.22/58	67	8.3	6.7	PSV	Completed	26	5	16	6
85	F	0.57/29	1.15/48	49	7.6	9.3	PCV	Completed	28	3	12	6
75	M	0.83/28	1.90/49	44	7.3	6.9	PCV	Completed	30	5	18	6
61	F	0.42/17	1.19/40	35	8.4	6.5	PCV	Completed	30	3	18	6
72	M	0.70/40	1.70/46	41	9.3	4.9	PSV	Completed	30	12	18	6
63	M	1.10/39	1.64/46	67	6.7	8.2	PSV	Completed	30	6	16	6
73	F	0.51/31	1.92/95	27	8.1	6.3	PSV	Withdrew, claustrophobia	20	5		6
74	M	0.86/34	2.05/62	42	5.9	6.6	PCV	Withdrew, acute exacerbation	22	3	14	6
87	M	1.24/50	2.09/63	59	7.3	8.5	PSV	Withdrew , intolerant of therapy	28	3		6
69	M	0.64/32	1.94/80	33	10.5	6.8	PSV	Withdrew, intolerant of therapy
79	F	0.71/38	1.05/46	68	9.6	8.7	PCV	Withdrew, prolonged central sleep apneas on PSV and withdrawn by clinical team	28	6	12	6

Abbreviations: M, male; F, female; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; PaO₂, arterial partial pressure of oxygen; PaCO₂, arterial partial pressure of carbon dioxide; PSV, pressure support (high-pressure) ventilation; PCV, pressure-controlled (high-intensity) ventilation; IPAP, inspiratory positive airway pressure; EPAP, expiratory positive airway pressure; BUR, backup rate.