Table 2—

Blood gas analysis according to the underlying disease prior(T0) to home mechanical ventilation (HMV), and 1 month (T1) and 12 months (T12) following the institution of HMV in patients who completed the study

	Disease categories	T0	T1	T12
P_a,CO₂mmHg	COPD	58.6±9.3	45.9±4.8***	44.5±7.2***
	RTD	51.5±8.4	46.2±4.5**	44.3±4.9***
	NMD	52.4±10.4	44.0±4.9***	41.3±7.4***
	OHS	53.5±6.6	41.4±3.3**	39.8±5.0**
P_a,O₂mmHg	COPD	49.0±6.0	62.0±8.9***	60.9±8.7***
	RTD	54.8±13.3	61.6±10.6***	64.5±9.7***
	NMD	66.2±14.3	72.6±13.8*	76.0±11.2***
	OHS	60.6±4.9	59.6±3.9	64.1±7.0
Bicarbonate mmol·L⁻¹	COPD	33.3±4.3	28.7±5.5**	27.7±5.8***
	RTD	30.4±8.7	27.7±4.8*	27.8±2.7
	NMD	29.2±4.7	26.7±2.9	25.6±2.3*
	OHS	31.6±3.6	27.4±2.3*	25.9±2.9*

Data are presented as mean±sd. P_a,CO₂: carbon dioxide arterial tension; P_a,O₂: arterial oxygen tension; COPD: chronic obstructive pulmonary disease; RTD: restrictive thoracic diseases; NMD: neuromuscular disorders; OHS: obesity hypoventilation syndrome. *: p<0.05; **: p<0.01; ***: p<0.001, compared with T0. 1 mmHg = 0.133 kPa.