A Wearable Respiratory Monitoring Device – the Between-Days Variability of Calibration

Abstract

The between-days variability in ascertained gain factors for calibration of a wearable respiratory inductance plethysmograph (RIP) and validity thereof for the repeated use during exercise were examined. Consecutive 5-min periods of standing still, slow running at 8 km·h^-1, fast running at 14 km·h^-1 (male) or 12 km·h^-1 (female) and recovery were repeated by 10 healthy subjects on 5 days. Breath-by-breath data were recorded simultaneously by flow meter and RIP. Gain factors were determined individually for each trial (CAL_IND) via least square regression. Reliability and variability in gain factors were quantified respectively by intraclass correlation coefficients (ICC) and limits of agreement. Within a predefined error range of ±20% the amount of RIP-derived tidal volumes after CAL_IND was compared to corresponding amounts when gain factors of the first trial were applied on the following 4 trials (CAL_FIRST). ICC ranged within 0.96 and 0.98. The variability in gain factors (up to ± 24.06%) was reduced compensatively by their sum. Amounts of breaths within the predefined error range did not differ between CAL_IND and (CAL_FIRST) (P>0.32). The between-days variability of gain factors for a wearable RIP-device does not show impaired reliability in further derived tidal volumes.

Key words

reproducibility - ventilation - running exercise - inductance plethysmography

• References

• 1 Atkinson G, Nevill AM. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med 1998; 26: 217-238
• 2 Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: 307-310
• 3 Bradley JM, Kent L, O’Neill B, Nevill A, Boyle L, Elborn JS. Cardiorespiratory measurements during field tests in CF: Use of an ambulatory monitoring system. Pediatr Pulmonol 2011; 46: 253-260
• 4 Brüllmann G, Fritsch K, Thurnheer R, Bloch KE. Respiratory monitoring by inductive plethysmography in unrestrained subjects using position sensor-adjusted calibration. Respiration 2010; 79: 112-120
• 5 Caretti DM, Pullen PV, La Premo, Kuhlmann WD. Reliability of respiratory inductive plethysmography for measuring tidal volume during exercise. Am Ind Hyg Assoc J 1994; 55: 918-923
• 6 Chadha TS, Watson H, Birch S, Jenouri GA, Schneider AW, Cohn MA, Sackner MA. Validation of respiratory inductive plethysmography using different calibration procedures. Am Rev Respir Dis 1982; 125: 644-649
• 7 Clarenbach CF, Senn O, Brack T, Kohler M, Bloch KE. Monitoring of ventilation during exercise by a portable respiratory inductive plethysmograph. Chest 2005; 128: 1282-1290
• 8 Grossman P, Wilhelm F, Brutsche M. Accuracy of ventilatory measurement employing ambulatory inductive plethysmography during tasks of everyday life. Biol Psychol 2010; 84: 121-128
• 9 Harriss DJ, Atkinson G. Ethical standards in sport and exercise science research: 2014 update. Int J Sports Med 2013; 34: 1025-1028
• 10 Heyde C, Leutheuser H, Eskofier B, Roecker K, Gollhofer A. Respiratory inductance plethysmography-a rationale for validity during exercise. Med Sci Sports Exerc 2014; 46: 488-495
• 11 Hopkins WG. Measures of reliability in sports medicine and science. Sports Med 2000; 30: 1-15
• 12 Jones B, Jarvis P, Lewis JA, Ebbutt AF. Trials to assess equivalence: the importance of rigorous methods. BMJ 1996; 313: 36-39
• 13 Kent L, O’Neill B, Davison G, Nevill A, Elborn JS, Bradley JM. Validity and reliability of cardiorespiratory measurements recorded by the LifeShirt during exercise tests. Respir Physiol Neurobiol 2009; 167: 162-167
• 14 Lafortuna CL, Passerini L. A new instrument for the measurement of rib cage and abdomen circumference variation in respiration at rest and during exercise. Eur J Appl Physiol 1995; 71: 259-265
• 15 Nevill AM, Atkinson G. Assessing agreement between measurements recorded on a ratio scale in sports medicine and sports science. Br J Sports Med 1997; 31: 314-318
• 16 Sackner JD, Nixon AJ, Davis B, Atkins N, Sackner MA. Non-invasive measurement of ventilation during exercise using a respiratory inductive plethysmograph. I. Am Rev Respir Dis 1980; 122: 867-871
• 17 Wilhelm F, Roth W, Sackner M. The lifeShirt. An advanced system for ambulatory measurement of respiratory and cardiac function. Behav Modif 2003; 27: 671-691
• 18 Witt J, Fisher J, Guenette J, Cheong K, Wilson B, Sheel A. Measurement of exercise ventilation by a portable respiratory inductive plethysmograph. Respir Physiol Neurobiol 2006; 154: 389-395