1. Anaesthetic conserving device AnaConDa®: dead space effect and significance for lung protective ventilation 
L.W. Sturesson, M. Bodelsson, B. Jonson, G. Malmkvist 
British Journal of Anaesthesia 
Volume 113, Issue 3, Pages (September 2014)
DOI: /bja/aeu102
Copyright © 2014 The Author(s) Terms and Conditions

2. Fig 1
Experimental set-up. (a) Servo Ventilator 900C, (b) tubes to the Y-piece, (c) CO2 transducer on ventilator side (CO2vent), (d) device tested (ACD or HME), (e) CO2 transducer on lung side (CO2lung), (f) tracheal tube, (g) patient lung (or test lung), (h) signals for flow from the ventilator, (i) signals from both CO2 analysers, (j) the computer, with (k) a screen displaying the signals.
British Journal of Anaesthesia  , DOI: ( /bja/aeu102)
Copyright © 2014 The Author(s) Terms and Conditions

3. Fig 2
(a) SBT-CO2 recorded with CO2vent shows fraction of CO2 (FeCO2) increasing during expiration (blue curve) and falling to zero during inspiration (green curve). The dashed vertical line indicates VDaw. The area under the expiratory limb represents the volume of expired CO2, VECO2. The area under the inspiratory limb (pink) represents volume of re-inspired CO2, VICO2. (b) Dark blue line shows expiratory data from (a) after integrating FeCO2 flow rate over time resulting in cumulating volume of expired CO2, VECO2. Measured volume of CO2 eliminated during the breath in (a) was calculated by subtracting VICO2 as indicated by the orange arrow. X-axis was renamed tidal volume (VT) for the purpose of illustrating CO2 exchange at alternative lower VT. For lower VT, VICO2 is less, reflecting lower end-tidal CO2. Therefore, the light blue curve, VTCO2, converges slightly with the dark blue curve. The light blue curve covering a volume range corresponding to the alveolar plateau was for this particular breath described by VTCO2= VT VT−7.75 (R2>0.99).
British Journal of Anaesthesia  , DOI: ( /bja/aeu102)
Copyright © 2014 The Author(s) Terms and Conditions

4. Fig 3
Airway dead space and CO2 rebreathing in patients. Airway dead space [VDaw, (a)] and fraction of CO2 rebreathing [VICO2%, (b)] in patients using the ACD with and without sevoflurane. The horizontal line at 230 ml represents VDaw of the HME plus the dead space effect of the larger internal volume of the ACD. Thus, parts of the bar above this line represent CO2 reflection from the carbon filter of the ACD. Values are mean (sd). P-values for differences between the means are given. One-way repeated measurement anova followed by the Holm–Sidak post hoc test (n=12).
British Journal of Anaesthesia  , DOI: ( /bja/aeu102)
Copyright © 2014 The Author(s) Terms and Conditions

5. Fig 4
Individual patient relationships (n=12) between tidal volume in ml kg−1 predicted body weight and RR assuming unaltered CO2 elimination and use of an ACD at 0.8% sevoflurane.
British Journal of Anaesthesia  , DOI: ( /bja/aeu102)
Copyright © 2014 The Author(s) Terms and Conditions

6. Fig 5
Mean tidal volume vs RR in patients for the ACD with sevoflurane 0% and 0.8%, for the HME and for a theoretical situation without any device. For clarity, the data are presented without statistical dispersion. For the sevoflurane 0.8% line, this is illustrated by the individual patient curves in Figure 4.
British Journal of Anaesthesia  , DOI: ( /bja/aeu102)
Copyright © 2014 The Author(s) Terms and Conditions

7. Fig 6
Airway dead space and CO2 rebreathing in a test lung. Airway dead space [VDaw, (a)] and fraction of CO2 rebreathing [VICO2%, (b)] in one ACD, measured with CO2vent or CO2lung as shown.
British Journal of Anaesthesia  , DOI: ( /bja/aeu102)
Copyright © 2014 The Author(s) Terms and Conditions