It very important to measure changes in breathing patterns among individuals as a change in breathing may be used to diagnosis and assess the state of a particular disease in and individual. The tidal breathing parameters that are normally measured include: respiratory rate (abbreviated as RR); Expiratory time (tE); the ratio of to time to peak tidal inspiratory flow to inspiratory time (tPTIF/tI); Inspiratory time (tI); Total Breathing time (tTot); Tidal Inspiratory flow over Tidal Expiratory flow at 50% of breathing (TIF/TIF) or wht is called IE50; (Time to peak tidal Expiratory flow) ÷ (Expiratory time), (tPTEF/tE); and so on. There are a number of ways in which these tidal breathing parameters may be quantified. These methods may be either novel (new) such as structured light plethysmography (abbreviated as SLP) or conventional (traditional) (Motamedi‐Fakhr, et al., 2017). Regardless of the method used, the results of these parameters must always be accurate within the stipulated clinical limit agreements especially when different methods of measuring tidal breathing parameters are being compared. The clinically accepted limit of agreement when measuring these parameters using two or more methods are as shown in table 1 below.
Table 1: Clinically accepted limit of agreement for quantifying tidal breathing parameters
| S/No | Parameter | Clinically accepted limit of agreement | Source of information |
| 1 | Respiratory Rate (RR) | ±2 breaths per minute | (Parker, et al., 2016), (Smith, Mackay, Fahrid , & Krucheck, 2011), and (Motamedi‐Fakhr, et al., 2017) |
| 2 | Inspiratory time (tI) | ±0.5 seconds | (Motamedi‐Fakhr, et al., 2017), (Chervin, Malhotra, & Burns, 2008), (Motamedi‐Fakhr, et al., 2013, (Walter & Vaughn, 2013) |
| 3 | Expiratory time (tE) | ±0.5 seconds | (Motamedi‐Fakhr, et al., 2017), (Chervin, Malhotra, & Burns, 2008), (Motamedi‐Fakhr, et al., 2013, (Walter & Vaughn, 2013) |
| 4 | Total Breathing time (tTot) | ±0.5 seconds | (Motamedi‐Fakhr, et al., 2017), (Chervin, Malhotra, & Burns, 2008), (Motamedi‐Fakhr, et al., 2013, (Walter & Vaughn, 2013) |
| 5 | (Time to peak tidal inspiratory flow) ÷ (inspiratory time), (tPTIF/tI) | Limit of agreement = ±16%, mean difference = ±5.5% | (Bentsen, Eriksen, Olsen, Markestad, & Halvorsen1, 2016) |
| 6 | (Time to peak tidal Expiratory flow) ÷ (Expiratory time), (tPTEF/tE) | Limit of agreement = ±16%, mean difference = ±5.5% | (Bentsen, Eriksen, Olsen, Markestad, & Halvorsen1, 2016), |
| 7 | Tidal Inspiratory flow over Tidal Expiratory flow at 50% of breathing (TIF/TIF) or wht is called IE50 | Limit of agreement = ±16%, mean difference = ±5.5% | (Motamedi‐Fakhr, et al., 2017), (Bentsen, Eriksen, Olsen, Markestad, & Halvorsen1, 2016), (DELLACA, et al., 2010), (Yuksel, Greenough, Giffin, & Nicolaides, 1996) |
- Bentsen, M. H., Eriksen, M., Olsen, M., Markestad, T., & Halvorsen1, T. (2016). Electromagnetic inductance plethysmography is well suited to measure tidal breathing in infants. ERJ Open Res, 2(4), 00062-02016.
- Chervin, R. D., Malhotra, R., & Burns, J. (2008). Respiratory cycle‐related EEG changes during sleep reflect esophageal pressures. Sleep, 31, 1713–1720.
- DELLACA, R. L., VENTURA, M., ZANNIN, E., NATILE, M., PEDOTTI, A., & TAGLIABUE, P. (2010). Measurement of Total and Compartmental Lung Volume Changes in Newborns by Optoelectronic Plethysmography. International Pediatric Research Foundation, Inc., 67(1), 11-16.
- Motamedi‐Fakhr, Moshrefi‐Torbati, M., Hill, M., Simpson, D., & Bucks. (2013). Respiratory cycle related EEG changes: modified respiratory cycle segmentation. Biomed. Signal Process. Control, 8, 838–844.
- Motamedi‐Fakhr, S., Richard, I., Barney, A., Boer, W., Conlon, J., Khalid, A., & Wilson, R. (2017). Evaluation of the agreement of tidal breathing parameters measured simultaneously using pneumotachography and structured light plethysmography. Physiol Rep, 5(3).
- Parker, R. A., Wei, C., Rubio, N., Rabinovich, R., Pinnock, H., & Hanley, J. (2016). Application of Mixed Effects Limits of Agreement in the Presence of Multiple Sources of Variability: Exemplar from the Comparison of Several Devices to Measure Respiratory Rate in COPD Patients. PLoS ONE, 11(12).
- Smith, I., Mackay, J., Fahrid , N., & Krucheck, D. (2011). Respiratory rate measurement: a comparison of methods. BJHCA , 5, 18–23.
- Walter, R. N., & Vaughn, B. (2013). Low frequency filtering of nasal pressure channel causes loss of flow limitation. Neurodiagn. J., 53, 58–62.
- Yuksel, B., Greenough, A., Giffin, F., & Nicolaides, H. (1996). Tidal breathing parameters in the first week of life and subsequent cough and wheeze. Thorax, 51, :815-818.