Unusual cause of muscle weakness, type II respiratory failure and pulmonary hypertension: a case report of ryanodine receptor type 1(RYR1)-related myopathy

Table 1 Arterial blood gas analysis while breathing room air, lung function test and polysomnography measurements

	Four months before	Baseline		Follow-up at 10 months
	Sitting position	Sitting position	Supine position	Sitting position	Supine position
Arterial blood gas analysis
pH		7.50	7.49		7.39
PaCO₂, mmHg		71	72		52
PaO₂, mmHg		52	38		68
SO₂, %		89	77		93
FiO₂		0.21	0.21		0.21
PFR, mmHg		247.62	180.95		323.81
Lung function test
FEV1, L		0.93	0.37	1.33
FEV1% (pred)	36.0	43.2	17.4	62.7
FVC, L		1.12	0.52	1.39
FVC% (pred)	34.0	44.1	20.7	55.3
FEV1/FVC, %		83.06	71.26	96.13
FEV1/FVC% (pred)	111.0	98.4	84.4	113.9
RV-SB, L		1.42		2.08
RV-SB % (pred)		97.0		140.4
TLC-SB, L		2.39		3.48
TLC-SB % (pred)		58.1		84.7
DLCO SB% (pred)	47.0	45.8		71.6
DLCO/VA, mmol/min/kPa/L		1.45		1.70
DLCO/VA % (pred)		82.4		97.2
Polysomnography
Hypopnea index, times per hour			119.6		1.2
Longest duration of hypopnea, seconds			63		51
Average SO₂ during sleep, %			73		96

PaCO₂ Partial pressure of carbon dioxide in arterial blood, PaO₂ Partial pressure of oxygen in arterial blood, SO₂ Blood oxygen saturation, FiO₂ Fraction of inspiration oxygen, PFR PaO₂/FiO₂ ratio, FEV1 Forced expiratory volume in one second, FVC Forced vital capacity, RV-SB Residual volume of single breath, TLC-SB Total lung capacity of single breath, DLCO SB Single-breath carbon monoxide diffusing capacity of the lungs, VA Alveolar ventilation

ISSN: 1471-2466