Influence of Driving Pressure on Raised-volume Forced Expiration in Infants

Hayden, Mark J.; Sly, Peter D.; Devadason, Sunalene G.; Gurrin, Lyle C.; Wildhaber, Johannes H.; Lesouëf, Peter

doi:10.1164/ajrccm.156.6.9609003

Cited by 22 publications

(14 citation statements)

References 16 publications

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“…The RVRTC technique has previously been shown to reliably detect both differences in airway obstruction between normal and recurrently wheezy infants and airway hyperresponsiveness [25, 26, 27]. Our study adds to the overall suitability of the RVRTC technique as differences in disease state can be detected and hence, long-term management can be guided.…”

Section: Discussionmentioning

confidence: 73%

Comparison of Subjective and Objective Measures in Recurrently Wheezy Infants

Wildhaber

Dore²,

Devadason³

et al. 2002

Respiration

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Objectives: The aim of this study was to compare subjective measures (overall health assessment both by the study physician and the child’s mother) with objective measurements of forced expiratory volumes (FEV_t) and maximal flow at functional residual capacity v̇_maxFRC) in recurrently wheezy infants. Methods: Sixteen wheezy infants (12 boys) aged 8–26 months were studied. A clinical assessment at visit 1 was followed by the run-in period during which day- and nighttime asthma symptom scores were obtained. The actual study period consisted of 2 visits when patient’s lung function was assessed. The first of which was during an acute exacerbation (visit 2), while the second was when the infant was asymptomatic (visit 3). FEV_t were obtained by the raised volume rapid thoracic compression technique (RVRTC) and v̇_maxFRC by the tidal volume rapid thoracic compression technique (TVRTC). Results: Mean FEV_t but not mean v̇_maxFRC were significantly lower at visit 2 compared to visit 3 (FEV_0.5: p = 0.005, and FEV_0.75: p = 0.002; v̇_maxFRC: p = 0.15) and correlated well with overall health assessment by the study physician (FEV_0.5: r = 0.82, and FEV_0.75: r = 0.84), but not with the overall health assessment by the mother. Conclusions: We have shown in the present study that objective measurements of FEV_t from a raised lung volume correlate well with the overall health assessment by the study physician; this was in contrast to measurements of v̇_maxFRC in the tidal volume range. We therefore conclude that the RVRTC technique is a feasible method to assess and monitor obstructive lung disease in infancy.

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Section: Discussionmentioning

confidence: 73%

Comparison of Subjective and Objective Measures in Recurrently Wheezy Infants

Wildhaber

Dore²,

Devadason³

et al. 2002

Respiration

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“…The system has been described previously 14. The compression jacket consisted of an inflatable plastic plate held over the chest and abdomen with a firm vinyl outer layer.…”

Section: Methodsmentioning

confidence: 99%

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

Morris

1999

Thorax

103

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Background-The functional residual capacity (FRC), the only lung volume to be routinely measured in infants, is an unreliable volume landmark. In addition to FRC, the residual volume (RV) was measured by nitrogen washout using rapid thoracoabdominal compression (RTC) in nine infants with cystic fibrosis aged 5-31 months. Methods-A commercial system for nitrogen washout to measure lung volumes and a custom made system to perform RTC were used. Lung volume was raised to an airway opening pressure of 30 cm H 2 O (V 30 ). RTC was performed from V 30 . The jacket pressure (Pj; 65-92 cm H 2 O) which generated the highest forced expiratory volume (mean 40.2 ml/kg; 95% confidence interval (CI) 33.03 to 47.33) was used during the RV manoeuvre. The infants were manually hyperventilated to inhibit the respiratory drive briefly. RTC was initiated during the last passive expiration. RV was estimated by measuring the volume of nitrogen expired after end forced expiratory switching of the inspired gas from room air to 100% oxygen while jacket inflation was maintained at the time of switching into oxygen during the postexpiratory pause. Results-In each infant RV and FRC measurements were reproducible and did not overlap; the diVerence between mean values, which is the expiratory reserve volume, was statistically significant (p<0.05). Mean RV was 21.3 (95% CI 18.7 to 24.0), FRC was 25.5 (95% CI 22.8 to 28.1), and TLC 30 (total lung capacity at V 30 ) was 61.5 (95% CI 54.4 to 68.7) ml/kg. These values were dependent on body length, weight and age. When measuring RV the period between switching to oxygen and the end of the Pj plateau was 0.301 (95% CI 0.211 to 0.391) s. The washout duration was longer for RV than for FRC measurement (80.9 s (95% CI 71.3 to 90.4) versus 72.4 s (95% CI 64.9 to 79.8)) (p<0.001). Conclusions-A new non-invasive and reliable technique for routine measurement of RV in infants is presented.

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“…27 As both lung inflation and deflation are well controlled in the RVRTC technique, it might remain less important for reproducibility of measurements whether flow limitation is reached or not. 8 Preliminary data, however, indicate that this technique generates flow limitation in healthy infants; 28 consequently, one may assume that the timed volumes measured in the present study stemmed from flow limited chest compression maneuvers.…”

Section: Discussionmentioning

confidence: 72%