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Table 2 Respiratory function tests, blood-gas analysis and subjective symptoms at the time of diagnosis

From: Using respiratory rate and thoracic movement to assess respiratory insufficiency in amyotrophic lateral sclerosis: a preliminary study

  Group 1   Group 2   
Measurement Mean (95% CI) n Mean (95% CI) n p*
Lung function tests     
FVC (%) 58 (44–72) 20 69 (58–74) 20 0.4
FEV 1/s (%) 59 (46–72) 20 69 (61–72) 20 0.2
Respiratory muscle force     
MIP (cmH2O) 29 (20–39) 21 48 (30– 65) 20 0.07
MEP (cmH2O) 40 (28–52) 21 60 (42–78) 20 0.07
SNP (cmH2O) 24 (9–40) 18 31 (21–41) 18 0.1
PCF (l/min) 240 (180–300) 18 310 (250–370) 20 0.1
Severity of hypoventilation symptoms    
Dyspnoea 4 (3–6) 21 2 (1–3) 20 0.05
Cough weakness 3 (2–5) 21 3 (1–4) 20 0.4
Sleep disturbance 5 (3–6) 21 3 (2–3) 20 0.05
Morning headaches 2 (0–3) 21 1 (0–2) 20 0.7
Daytime sleepiness 4 (3–6) 21 4 (2–5) 20 0.4
Thoracic movement (cm) 2.9 (2.2–3.6) 22 4.0 (3.4–4.8) 20 0.01
Respiratory rate (breaths/min) 21 (18–24) 22 16 (14–18) 20 0.005
Arterial blood-gas analysis     
pCO2 (kPa) 6.3 (5.6–6.9) 17 5.3 (5.0–5.6) 12 0.007
pO2 (kPa) 9.8 (9.3–10.4) 17 10.7 (9.4–12) 12 0.4
  1. *Determined using the Mann Whitney U test.
  2. n = number of patients completing the measurement; CI = confidence interval; FVC = forced vital capacity expressed as % from the reference values; FEV 1 = forced expiratory volume exhaled in one second and expressed as % from the reference values; MIP = maximal inspiratory mouth pressure; MEP = maximal expiratory mouth pressure; SNP = sniff nasal pressure; PCF = peak cough flow. All measurements were performed three times in a sitting position and the best values were recorded.
  3. The severity of hypoventilation symptoms was assessed using a visual analogue scale (VAS) in which 0 represented no symptoms and 10 represented the worst symptoms that the patients could imagine. Thoracic movement was measured using a measuring tape and recorded as the difference in the thoracic circumference during maximal inspiration and expiration at the mammillary level.