A Randomized Controlled Trial of Noninvasive Ventilation with Pressure Support Ventilation and Adaptive Support Ventilation in Acute Exacerbation of COPD: A Feasibility Study

Figures & data

Figure 1. CONSORT diagram depicting the flow of subjects during the study.

Table 1. Baseline demographic, clinical and ICU parameters.

Parameter	ASV (n = 36)	PSV (n = 38)	P value
Demographics
Age, years	61.5 ± 8.1	59.9 ± 10.6	0.39
Male sex, n (%)	27 (75)	31 (81.6)	0.58
Clinical parameters
Respiratory rate, breaths/min	26.9 ± 6.3	24.3 ± 5.9	0.07
Heart rate, beats/min	97.9 ± 16.7	100.3 ± 18.9	0.58
Mean arterial pressure, mm Hg	88.2 ± 15.3	87.8 ± 13.4	0.9
Glasgow coma scale	14 ± 2	13 ± 3.5	0.28
APACHE II score	10.7 ± 4	10.5 ± 4.4	0.85
SOFA score	4.7 ± 2.2	4.8 ± 2.8	0.94
Investigations
Haemoglobin, g/dL	13.4 ± 2.3	13.3 ± 2.5	0.81
Total leucocyte count, cells/mm^3	12842 ± 6370	10442 ± 4226	0.06
Platelet count, x10^3 cells/mm^3	2.6 ± 1.9	2.2 ± 1.7	0.37
Plasma glucose	147.6 ± 55.9	147.2 ± 45.5	0.97
Serum creatinine	0.86 ± 0.34	0.98 ± 0.52	0.26
Blood gas variables
pH	7.29 ± 0.06	7.27 ± 0.06	0.79
PaCO2	71.4 ± 14.7	70.8 ± 11.9	0.76
HCO3^-	33.9 ± 9.1	31.9 ± 5.9	0.62
PaO2	70.5 ± 34.9	73.6 ± 39.2	0.99
PaO2:FiO2 ratio	245.6 ± 112.6	257.6 ± 129.1	0.67
NIV parameters
Peak inspiratory pressure, cm H2O	18.1 ± 4.3	14.8 ± 3.6	<0.01
PEEP, cm H2O	4.6 ± 0.5	4.6 ± 0.8	0.96
Tidal volume, mL/kg IBW	6.7 ± 1.7	5.9 ± 1.3	0.04
%MinVol, median (range)	100 (100–150)	—

All values are expressed as mean ± SD, unless specified.

APACHE, acute physiology and chronic health evaluation; MinVol: minute volume; NIV, noninvasive ventilation; Pa_O2, partial pressure of oxygen in arterial blood; Pa_O2:Fi_O2 ratio, ratio of partial pressure of oxygen in arterial blood and fraction of oxygen in the inspired air; Pa_CO2, partial pressure of carbon dioxide in arterial blood; PEEP, positive end-expiratory pressure; SOFA, sequential organ failure assessment.

Table 2. Outcome parameters.

	ASV (n = 36)	PSV (n = 38)	Estimate difference (95% confidence interval)	P value
Primary outcome
NIV failure	8 (22.2)	13 (34.2)	−0.12 (−0.3 to 0.09)	0.31
Intubation rate, n (%)	4 (11.1)	8 (21.1)	−0.09 (−0.3 to 0.07)	0.14
Deaths, n (%)	4 (11)	2 (5.3)	0.06 (−0.08 to 0.2)	0.31
Requirement of NIV within 48 h	0	3 (7.9)	−0.08 (−0.2 to 0.03)	0.24
Secondary outcomes
Duration of NIV, hours	34.5 ± 26.9	26.2 ± 23.1	8.3 (−3.3 to 19.9)	0.16
Time to intubation, hours	12.5 ± 14.8	5.4 ± 6.1	7.1 (−5.9 to 20.1)	0.62
Duration of mechanical ventilation, hours*	39.8 ± 36.2	46.9 ± 59.6	−7.1 (−30.1 to 15.9)	0.54
VAS for patient comfort	42.1 ± 21.6	35.3 ± 18.3	6.8 (−2.5 to 16.1)	0.19
VAS for physician ease	38.7 ± 19.0	38.6 ± 20.2	0.1 (−9 to 9.2)	0.97
No. of NIV manipulations, per day	6.0 ± 2.4	5.6 ± 2.4	0.4 (−0.7 to 1.5)	0.55
Complications, n (%)	4 (11.1)	6 (15.8)	−0.05 (−0.21 to 0.1)	0.4
Weaning failure, n (%)	6 (16.7)	4 (10.5)	0.06 (−0.1 to 0.2)	0.33
ICU LOS, days	4.8 ± 3.6	5.3 ± 4.5	−0.5 (−2.1 to 1.4)	0.61
Hospital LOS, days	7.7 ± 3.5	8.6 ± 5.7	−0.9 (−3.1 to 1.3)	0.39

All values are expressed as mean ± SD, unless specified.

LOS, length of stay; NIV, noninvasive ventilation; VAS, visual analog score; ICU: intensive care unit.

*Includes invasive and noninvasive ventilation.

Figure 2. Kaplan–Meier survival curves comparing the cumulative probability of endotracheal intubation in pressure support ventilation (PSV) and adaptive support ventilation (ASV) mode during noninvasive ventilation use during intensive care unit stay

Table 3. Serial clinical and arterial blood gas parameters during the initial 24 h of noninvasive ventilation.

	Adaptive support ventilation (ASV)					Pressure support ventilation (PSV)
Parameter/time	0 h	1 h	2 h	4 h	24 h	0 h	1 h	2 h	4 h	24 h
RR	26.9 ± 6.3	25.3 ± 5.5^a	23.8 ± 6.1^a	21.8 ± 5.4^a	20.8 ± 5.6^a	24.3 ± 5.9^a	25.0 ± 4.9^a	23.3 ± 5.5^a	25.8 ± 10.8^a	22.2 ± 4.8^a
HR	97.9 ± 16.7	98.8 ± 17.4^a	98.2 ± 20.3^a	91.0 ± 14.9^a	92.3 ± 13.0^a	100.3 ± 18.9^a	96.9 ± 19.0^a	93.2 ± 17.5^a	88.4 ± 17.2^a	88.6 ± 18.2^a
pH	7.29 ± 0.05	7.31 ± 0.08^a	7.32 ± 0.08^a	7.34 ± 0.07^a	7.38 ± 0.06^a	7.27 ± 0.06^a	7.29 ± 0.08^a	7.31 ± 0.08^a	7.32 ± 0.09^a	7.36 ± 0.07^a
PaCO2	71.4 ± 14.7	66.5 ± 19.6^a	65.8 ± 15.4^a	62.6 ± 17.1^a	60.4 ± 11.8^a	70.8 ± 11.9^a	69.8 ± 12.9^a	67.4 ± 14.2^a	64.1 ± 12.7^a	63.9 ± 14.1^a
PIP	18.1 ± 4.3	17.4 ± 4.2^b	17.6 ± 4.6^b	16.3 ± 4.9^b	13.4 ± 5.2^a	14.8 ± 3.6^b	14.8 ± 3.4^b	14.6 ± 3.9^b	13.8 ± 3.9^b	13.9 ± 3.2
PEEP	4.6 ± 0.5	4.9 ± 0.5	4.9 ± 0.4	4.9 ± 0.5	5.1 ± 0.4	4.6 ± 0.8	4.8 ± 0.7	4.8 ± 0.6	4.7 ± 0.5	4.9 ± 0.5
VT, kg/IBW	6.7 ± 1.7	7.3 ± 2.3^b	7.2 ± 1.8^c	6.8 ± 1.9^c	6.8 ± 1.3^c	6 ± 1.3^c	6.1 ± 1.3^c	6.2 ± 1.3^c	6.5 ± 1.3^c	6.5 ± 1.5^c

*All values are in mean ± SD.

IBW, ideal body weight; HR, heart rate/min; Pa_CO2, partial pressure of carbon dioxide in arterial blood; PEEP, positive end-expiratory pressure (cm H₂O); PIP, peak inspiratory pressure (cm H₂O); RR, respiratory rate/min; VT, tidal volume.

^a Values significantly different from the baseline within group.

^b Values significantly different between and within groups from the baseline.

^c Values significantly different between groups.