A novel non-invasive technique for measuring the residual lung volume by nitrogen washout with rapid thoracoabdominal compression in infants

Morris, Mohy G.

doi:10.1136/thx.54.10.874

Cited by 14 publications

(105 citation statements)

References 15 publications

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“…1 and includes a: clear face mask; three-way switching valve with two inlet/outlet ports and a mask port; T-piece; pneumotachometer (PNT); O 2 supply with a precision flowmeter (0 -15 L . min -1 ); N 2 analyser and mixing chamber; calibrating syringe; collapsible breathing bag and a T-connection (recommended; see later) [11,12].…”

Section: Equipment Requiredmentioning

confidence: 99%

“…When switched into pure O 2 during the washout, the infant no longer breathes through the PNT ( fig. 1) [7,12]. Connecting the PNT to the inlet/outlet port of the three-way valve is the preferred placement because this decreases the dead space and resistance during the washout.…”

Section: Equipment Requiredmentioning

confidence: 99%

“…For a detailed discussion regarding the use of automatic breath identification, see BATES et al [26]. 2) Manual, whereby the operator waits until a stable tidal breathing (end-expiratory level) pattern is observed in real time on the computer monitor and activates the slide valve as close as possible to end-expiration in a chosen breath [3,7,12]. This mode requires an experienced operator but is useful if the infant has irregular breathing. )…”

Section: Equipment Requiredmentioning

confidence: 99%

“…A long (y2.0 m), low resistance tubing is attached to the outlet port of the mixing chamber to prevent ambient air from diffusing back into the mixing chamber. A chamber volume of about 500 mL would be adequate, even in toddlers, particularly if a collapsible breathing bag is incorporated in the circuit (see later) [11,12].…”

Section: Equipment Requiredmentioning

confidence: 99%

“…This minimizes flow swings within the N 2 mixing chamber during the breathing cycle as well as the retrograde movement of mixed O 2 and N 2 gas after it passes beyond the N 2 sampling needle port. In addition, the bag can be used to monitor the infant9s breathing pattern both during the washout and when determining the "end of test" (see later) [11,12].…”

Section: Equipment Requiredmentioning

confidence: 99%

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The bias flow nitrogen washout technique for measuring the functional residual capacity in infants

et al. 2001

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The functional residual capacity (FRC) is the most commonly measured static lung volume in infants. It is important for interpreting volume-dependent pulmonary mechanics,e.g.airway resistance, and defining normal lung growth. The bias flow nitrogen washout technique is widely used for measuring FRC because the dead space and circuit resistance are low, making it suitable for small or sick infants. Moreover, data acquisition and calculation are easily programmed for a personal computer.The aim of this paper is to provide recommendations pertaining to equipment requirements, study procedures and reporting of data for functional residual capacity measurements. While measuring the functional residual capacity is regarded as physiologically and clinically important, the accuracy of the measurement is undoubtedly equally important. Hence, the paper also emphasizes factors influencing the accuracy of functional residual capacity measurements independent of equipment requirements. These recommendations represent the “State of the Art” in 2000.

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Section: Equipment Requiredmentioning

confidence: 99%

Section: Equipment Requiredmentioning

confidence: 99%

Section: Equipment Requiredmentioning

confidence: 99%

Section: Equipment Requiredmentioning

confidence: 99%

Section: Equipment Requiredmentioning

confidence: 99%

See 3 more Smart Citations

The bias flow nitrogen washout technique for measuring the functional residual capacity in infants

et al. 2001

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Exploring the relationship between forced maximal flow at functional residual capacity and parameters of forced expiration from raised lung volume in healthy infants

Ranganathan¹,

Hoo²,

Lum³

et al. 2002

Pediatric Pulmonology

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The raised volume rapid thoraco-abdominal compression technique (RVRTC) is being increasingly used to assess airway function in infants, but as yet no consensus exists regarding the equipment, methods, or analysis of recorded data. The aim of this study was to explore the relationship between maximal flow at functional residual capacity (V'(maxFRC)) and parameters derived from raised lung volumes, and to address analytical aspects of the latter technique in an attempt to assist with future standardization initiatives. Forced vital capacity (FVC) from lung volume raised to 3 kPa, timed forced expiratory volumes (FEV(t)), and forced expiratory flow parameters at different percentages of expired FVC (FEF(%)) were measured in 98 healthy infants (1-69 weeks of age). V'(maxFRC) using the tidal rapid thoraco-abdominal compression (RTC) technique was also measured. The within-subject relationships and within-subject variability of the various parameters were assessed. Duration of forced expiration was < 0.5 sec in 5 infants, meaning that FEV(0.3) and FEV(0.4) were the only timed volume parameters that could be calculated in all infants during the first months of life, and even when it could be calculated, FEV(0.5) approached FVC in many of these infants. It is recommended that FEV(0.4) be routinely reported in infants less than 3 months of age. Contrary to previous reports, within subject variability of V'(maxFRC) was less than that of FEF(75) (mean CV = 6.3% and 8.9%, respectively).A more standardized protocol when analyzing data from the RVRTC would facilitate comparisons of results between centers in the future.

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Lung function testing in infants with cystic fibrosis: Lessons from the past and future directions

Gappa

Ranganathan²,

Stocks³

2001

Pediatric Pulmonology

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Despite the increasing awareness of the need to identify early pulmonary changes in cystic fibrosis (CF) noninvasively, the role of lung function testing in infancy and early childhood remains less clear than in older children with CF. The aim of this review is to summarize available data, discuss the information gained from these publications, and put this information into perspective with more recent developments of lung function testing in both infants and older children with CF. While some of the available data have been the foundation of the current level of understanding of respiratory physiology in CF, interpretation of other data has been hampered by differences between centers with regard to the methods and equipment used, patient selection, small number of subjects, and lack of appropriate reference data. A structured multicenter approach based on recently published recommendations for the measurement of lung function in infancy, together with pursuit of recent developments such as assessment of raised lung volume flow volume curves and ventilation inhomogeneity may help to more effectively utilize lung function tests in infants in the future.

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A novel non-invasive technique for measuring the residual lung volume by nitrogen washout with rapid thoracoabdominal compression in infants

Cited by 14 publications

References 15 publications

The bias flow nitrogen washout technique for measuring the functional residual capacity in infants

The bias flow nitrogen washout technique for measuring the functional residual capacity in infants

Exploring the relationship between forced maximal flow at functional residual capacity and parameters of forced expiration from raised lung volume in healthy infants

Lung function testing in infants with cystic fibrosis: Lessons from the past and future directions

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