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Author(s): Rory Chan [sup.1], Brian Lipworth [sup.1] Author Affiliations: (1) grid.8241.f, 0000 0004 0397 2876, Scottish Centre for Respiratory Research, School of Medicine, Ninewells Hospital, University of Dundee, , DD1 [...], Introduction Forced vital capacity (FVC) is often preserved in severe asthma unless there is evidence of either airway remodelling or air trapping. Area under the reactance curve (AX) can be used to assess small airways dysfunction related lung stiffness and is related to disease control in severe asthma. Methods We explore if there may be a potential synergistic interaction between FVC and AX in terms of impaired asthma control as ACQ and exacerbations requiring oral corticosteroids (OCS). We pragmatically defined < 100% and [greater than or equal to] 1.0 kPa/L/s as impaired FVC or AX, respectively. Results Patients with combined impairment of FVC and AX had significantly worse asthma control as higher ACQ, more severe exacerbations requiring OCS and worse spirometry (FEV.sub.1 and FEF.sub.25-75) than those with impaired FVC but preserved AX. Conclusion This in turn supports using both spirometry and oscillometry to characterise airway physiology more comprehensively in patients with more severe asthma.

Byline: Raffaele L. Dellaca (1), Marie Andersson Olerud (2), Emanuela Zannin (1), Peter Kostic (2), Pasquale P. Pompilio (1), Goran Hedenstierna (3), Antonio Pedotti (1), Peter Frykholm (2) Keywords: Forced oscillation technique; ALI/ARDS; Mechanical ventilation; PEEP; Respiratory mechanics Abstract: Purpose ALI and ARDS are associated with lung volume derecruitment, usually counteracted by PEEP and recruitment maneuvers (RM), which should be accurately tailored to the patient's needs. The aim of this study was to investigate the possibility of monitoring the amount of derecruited lung by the forced oscillation technique (FOT). Methods We studied six piglets (26 +- 2.5 kg) ventilated by a mechanical ventilator connected to a FOT device that produced sinusoidal pressure forcing at 5 Hz. The percentage of non-aerated lung tissue (V tiss.sub.NA%) was measured by whole-body CT scans at end-expiration with zero end-expiratory pressure. Respiratory system oscillatory input reactance (X .sub.rs) was measured simultaneously to CT and used to derive oscillatory compliance (C .sub.X5), which we used as an index of recruited lung. Measurements were performed at baseline and after several interventions in the following sequence: mono-lateral reabsorption atelectasis, RM, bi-lateral derecruitment induced by broncho-alveolar lavage and a second RM. Results By pooling data from all experimental conditions and all pigs, C .sub.X5 was linearly correlated to V tiss.sub.NA% (r .sup.2 = 0.89) regardless of the procedure used to de-recruit the lung (reabsorption atelectasis or pulmonary lavage). Separate correlation analysis on single pigs showed similar regression equations, with an even higher coefficient of determination (r .sup.2 = 0.91 +- 0.07). Conclusion These results suggest that FOT and the measurement of C .sub.X5 could be a useful tool for the non-invasive measurement of lung volume recruitment/derecruitment. Author Affiliation: (1) Dipartimento di Bioingegneria, Politecnico di Milano University, Piazza Leonardo da Vinci 32, 20133, Milan, Italy (2) Department of Surgical Sciences, Anaesthesia and Intensive Care, Uppsala University, Uppsala, Sweden (3) Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden Article History: Registration Date: 10/09/2009 Received Date: 19/01/2009 Accepted Date: 02/09/2009 Online Date: 30/09/2009 Article note: Electronic supplementary material The online version of this article (doi: 10.1007/s00134-009-1673-3) contains supplementary material, which is available to authorized users.

Byline: Ido G. Bikker (1), Thierry V. Scohy (2), Ad J. J. C. Bogers (3), Jan Bakker (1), Diederik Gommers (1,2) Keywords: Functional residual capacity; Pediatric; Positive-pressure respiration; Lung volume measurements; Anesthesiology Abstract: Purpose Monitoring end-expiratory lung volume (EELV) is a valuable tool to optimize respiratory settings that could be of particular importance in mechanically ventilated pediatric patients. We evaluated the feasibility and precision of an intensive care unit (ICU) ventilator with an in-built nitrogen washout/washin technique in mechanically ventilated pediatric patients. Methods Duplicate EELV measurements were performed in 30 patients between 5 kg and 43 kg after cardiac surgery (age, median + range: 26, 3--141 months). All measurements were taken during pressure-controlled ventilation at 0 cm [H.sub.2]O of positive end-expiratory pressure (PEEP). Results Linear regression between duplicate measurements was excellent (R .sup.2 = 0.99). Also, there was good agreement between duplicate measurements, bias +- SD: -0.3% (-1.5 mL) +- 5.9% (19.2 mL). Mean EELV +- SD was 19.6 +- 5.1 mL/kg at 0 cm [H.sub.2]O PEEP. EELV correlated with age (p < 0.001, r = 0.92, R .sup.2 = 0.78), body weight (p < 0.001, r = 0.91, R .sup.2 = 0.82) and height (p < 0.001, r = 0.94, R .sup.2 = 0.75). Conclusion This ICU ventilator with an in-built nitrogen washout/washin EELV technique can measure EELV with precision, and can easily be used for mechanically ventilated pediatric patients. Author Affiliation: (1) Department of Intensive Care Medicine, Erasmus MC, Room H602, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands (2) Department of Anesthesiology, Erasmus MC, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands (3) Department of Cardiothoracic Surgery, Erasmus MC, 's-Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands Article History: Registration Date: 08/07/2009 Received Date: 15/12/2008 Accepted Date: 20/06/2009 Online Date: 23/07/2009

This investigation compared percent fat obtained via underwater weighing using measured and predicted residual lung volume (RLV) in euhydrated and hypehydrated collegiate wrestlers (N = 67). RLV was measured using [O.sub.2] rebreathing or [0.sub.2] dilution and predicted using 3 equations--Equation 1:(0.019 x height [cm]) + (0.0115 x age [years])--2.24; Equation 2: (0.017 x age [years]) + (0.06858 x height [in.])--3.477; and Equation 3: (0.0275 age [years]) + (0.0189 height [cm])--2.6139. Percent fat determined using RLV Equation 2 did not differ from the value obtained using measured RLV in the euhydrated (10.9 (+ or -] 5.1 vs. 11.5 [+ or -] 5.6% fat) or hypohydrated (10.8 [+ or -] 5.1 vs. 12.3 [+ or -] 5.6% fat) trials. All other percent fat values differed (p < 0.05) from the value obtained using measured RLV in euhydrated subjects. The use of RLV Equation 2 may be a practical alternative to measured RLV in determining percent fat in euhydrated and hypohydrated collegiate wrestlers. KEY WORDS. percent fat, hydration status, hydrostatic weighing

Established procedures for making chest wall kinematic observations (Hoit & Hixon, 1987) and pressure-flow observations (Smitheran & Hixon, 1981) were used to study respiratory Kand laryngeal function during whispering and speaking in 10 healthy young adults. Results indicate that whispering involves generally lower lung volumes, lower tracheal pressures, higher translaryngeal flows, lower laryngeal airway resistances, and fewer syllables per breath group when compared to speaking. The use of lower lung volumes during whispering than speaking may relfect a means of achieving different tracheal pressure targets. Reduction in the number of syllables produced per breath group may be an adjustment to the high rate of air expenditure accompanying whispering compared to speaking. Performance of the normal subjects studied in this investigation does not resemble that of individuals with speech and voice disorders characterized by low resistive loads. KEY WORDS: respiratory, whisper, speech, laryngeal