Figures
- FIGURE 1
Illustration of the set-up for cardiopulmonary exercise test (CPET) with and without continuous video laryngoscopy. The upper left and right images demonstrate the facemask used for ordinary CPET. The middle left and right images demonstrate the modified facemask with a flexible transnasal laryngoscope positioned through a tight-fit opening. A custom-made headgear secures the body of the laryngoscope. The attached transnasal flexible laryngoscope enables video recording of the laryngeal inlet during the maximal exercise treadmill test (bottom image).
- FIGURE 2
Agreement between peak oxygen consumption (V′O2peak), respiratory exchange ratio (RER) and minute ventilation (V′E) obtained from cardiopulmonary exercise testing (CPET) and continuous laryngoscopy performed during exercise (CLE) test. The horizontal lines depict the mean difference between the variables obtained with the two methods, whereas ±1.96 sd of these differences represent 95% limits of agreement between the two methods. The 95% confidence intervals for the mean, the upper limit of agreement and the lower limit of agreement are indicated by vertical lines. The figures given below in the brackets are the mean difference and the upper and lower limits of agreement, expressed as percentages of the mean of the CPET and CLE value. a) Agreement between V′O2peak, expressed as mL·kg−1·min−1, obtained from CPET and CLE tests. The mean difference was 0.2 mL·kg−1·min−1 (0.4%), the upper limit of agreement was 4.0 mL·kg−1·min−1 (7.0%), and the lower limit of agreement was −3.5 mL·kg−1·min−1 (−6.2%). b) Agreement between RER obtained from CPET and CLE test at peak exercise. The mean difference was 0.01 units (0.7%), the upper limit of agreement was 0.11 units (9.2%), and the lower limit of agreement was −0.09 units (−7.8%). c) Agreement between V′E obtained from CPET and CLE test at peak exercise. The mean difference was 2.58 L·min−1 (2.2%), the upper limit of agreement was 26.5 L·min−1 (18.3%), and the lower limit of agreement was −21.4 L·min−1 (−13.9%).
Tables
- TABLE 1
Characteristics of the 40 subjects comparing peak oxygen consumption measured with or without continuous laryngoscopy during cardiopulmonary exercise test on a treadmill
Female sex n (%) 21 (53) Age years mean (range) 24.8 (15.0 to 35.0) BMI kg·m−2 22.3±2.3 Smoking n (%) 0 (0) Exercise 4–6 days per week n (%) 19 (47.5) Daily n (%) 21 (52.5) Asthma n (%) 1 (3) FVC CPET L 5.12±1.26 FVC CLE L 5.15±1.25 FVC z-score CPET 0.25±0.81 FVC z-score CLE 0.30±0.79 FEV1 CPET L 4.31±1.32 FEV1 CLE L 4.20±0.92 FEV1 z-score CPET 0.05±0.83 FEV1 z-score CLE 0.07±0.79 Data are presented as mean±sd, unless otherwise stated. BMI: body mass index; FVC: forced vital capacity; CPET: cardiopulmonary exercise test; CLE: continuous laryngoscopy during exercise; FEV1: forced expiratory volume in 1 s.
- TABLE 2
Ergospirometry data for the 40 participants obtained from cardiopulmonary exercise tests performed without and with added CLE test set-up
Parameter CPET without CLE CPET with CLE Difference Mean sd Mean sd Mean (95% CI) V′O2peak mL·min−1 3818 873.8 3806 883.4 11.4 (−33.5, 56.2) V′O2peak mL·kg−1·min−1 54.9 6.3 54.7 6.6 0.22 (−0.40, 0.83) V′CO2peak mL·min−1 4618 1016 4565 1006 53.1 (−25.9, 132.0) VT L 2.61 0.65 2.61 0.62 0.005 (−0.08, 0.071) V′E L·min−1 142.3 33.1 139.7 34.2 2.58 (−1.33, 6.49) HR beats·min−1 186 8.7 185 9.0 1.4 (−0.8, 3.5) RR breaths·min−1 55 9.3 54 10.0 1.2 (−1.5, 4.0) RER units 1.21 0.05 1.20 0.05 0.01 (−0.007, 0.027) Distance m 1199 219 1150 210 49 (15.7, 82.0) CLE: continuous laryngoscopy during exercise; CPET: cardiopulmonary exercise test; V′O2peak: oxygen consumption at peak exercise; V′CO2peak: carbon dioxide production at peak exercise; VT: tidal volume; V′E: minute ventilation; HR: heart rate; RR: respiratory rate; RER: respiratory exchange rate.
- TABLE 3
Reliability and reproducibility of the ergospirometry data obtained for the 40 participants performing cardiopulmonary exercise test with and without CLE test set-up
Parameter Agreement Lower LoA Upper LoA ICC (95% CI) WS-sd CoV % V′O2peak mL·min−1 11.4 −263 286 0.988 (0.977, 0.993) 98 2.6 V′O2peak mL·kg−1·min−1 0.2 −3.5 4.0 0.957 (0.920, 0.977) 1.3 2.5 V′CO2peak mL·min−1 53.1 −431 537 0.970 (0.943, 0.984) 176 3.8 VT L 0.0 −0.47 0.46 0.933 (0.876, 0.964) 0.16 6.3 V′E L·min−1 2.6 −21.4 26.5 0.933 (0.877, 0.964) 8.7 6.2 HR beats·min−1 1.4 −11.6 14.3 0.720 (0.532, 0.841) 4.7 2.5 RR breaths·min−1 −2.5 −19.9 15.0 0.614 (0.375, 0.777) 6.0 11.1 RER units 0.01 −0.09 0.11 0.502 (0.233, 0.700) 0.04 3.1 CLE: continuous laryngoscopy during exercise; LoA: limit of agreement; ICC: intraclass correlation coefficient; WS-sd: within-subject sd; CoV: coefficient of variation; V′O2peak: oxygen consumption at peak exercise; V′CO2peak: carbon dioxide production at peak exercise; VT: tidal volume; V′E: minute ventilation; HR: heart rate; RR: respiratory rate; RER: respiratory exchange rate.
