BACKGROUND: Changes in the shape of the capnogram may reflect changes in lung physiology. We studied the effect of different ventilation/perfusion ratios (V/Q) induced by positive end-expiratory pressures (PEEP) and lung recruitment on phase III slope (S(III)) of volumetric capnograms. METHODS: Seven lung-lavaged pigs received volume control ventilation at tidal volumes of 6 ml/kg. After a lung recruitment maneuver, open-lung PEEP (OL-PEEP) was defined at 2 cmH(2)O above the PEEP at the onset of lung collapse as identified by the maximum respiratory compliance during a decremental PEEP trial. Thereafter, six distinct PEEP levels either at OL-PEEP, 4 cmH(2)O above or below this level were applied in a random order, either with or without a prior lung recruitment maneuver. Ventilation-perfusion distribution (using multiple inert gas elimination technique), hemodynamics, blood gases and volumetric capnography data were recorded at the end of each condition (minute 40). RESULTS: S (III) showed the lowest value whenever lung recruitment and OL-PEEP were jointly applied and was associated with the lowest dispersion of ventilation and perfusion (Disp(R-E)), the lowest ratio of alveolar dead space to alveolar tidal volume (VD(alv)/VT(alv)) and the lowest difference between arterial and end-tidal pCO(2) (Pa-ETCO(2)). Spearman's rank correlations between S(III) and Disp(R-E) showed a ρ=0.85 with 95% CI for ρ (Fisher's Z-transformation) of 0.74-0.91, P<0.0001. CONCLUSION: In this experimental model of lung injury, changes in the phase III slope of the capnograms were directly correlated with the degree of ventilation/perfusion dispersion.
BACKGROUND: Changes in the shape of the capnogram may reflect changes in lung physiology. We studied the effect of different ventilation/perfusion ratios (V/Q) induced by positive end-expiratory pressures (PEEP) and lung recruitment on phase III slope (S(III)) of volumetric capnograms. METHODS: Seven lung-lavaged pigs received volume control ventilation at tidal volumes of 6 ml/kg. After a lung recruitment maneuver, open-lung PEEP (OL-PEEP) was defined at 2 cmH(2)O above the PEEP at the onset of lung collapse as identified by the maximum respiratory compliance during a decremental PEEP trial. Thereafter, six distinct PEEP levels either at OL-PEEP, 4 cmH(2)O above or below this level were applied in a random order, either with or without a prior lung recruitment maneuver. Ventilation-perfusion distribution (using multiple inert gas elimination technique), hemodynamics, blood gases and volumetric capnography data were recorded at the end of each condition (minute 40). RESULTS: S (III) showed the lowest value whenever lung recruitment and OL-PEEP were jointly applied and was associated with the lowest dispersion of ventilation and perfusion (Disp(R-E)), the lowest ratio of alveolar dead space to alveolar tidal volume (VD(alv)/VT(alv)) and the lowest difference between arterial and end-tidal pCO(2) (Pa-ETCO(2)). Spearman's rank correlations between S(III) and Disp(R-E) showed a ρ=0.85 with 95% CI for ρ (Fisher's Z-transformation) of 0.74-0.91, P<0.0001. CONCLUSION: In this experimental model of lung injury, changes in the phase III slope of the capnograms were directly correlated with the degree of ventilation/perfusion dispersion.
Authors: Martina Mosing; Annette P N Kutter; Samuel Iff; Joanna Raszplewicz; Jacqueline Mauch; Stephan H Bohm; Gerardo Tusman Journal: J Clin Monit Comput Date: 2014-06-08 Impact factor: 2.502
Authors: Tommaso Mauri; Nilde Eronia; Cecilia Turrini; Marta Battistini; Giacomo Grasselli; Roberto Rona; Carlo Alberto Volta; Giacomo Bellani; Antonio Pesenti Journal: Intensive Care Med Date: 2016-08-12 Impact factor: 17.440
Authors: Slava M Belenkiy; William L Baker; Andriy I Batchinsky; Sumit Mittal; Taylor Watkins; Jose Salinas; Leopoldo C Cancio Journal: Int J Burns Trauma Date: 2015-10-12
Authors: Barna Babik; Zsófia Csorba; Dorottya Czövek; Patrick N Mayr; Gábor Bogáts; Ferenc Peták Journal: Crit Care Date: 2012-10-02 Impact factor: 9.097
Authors: Kaspar F Bachmann; Matthias Haenggi; Stephan M Jakob; Jukka Takala; Luciano Gattinoni; David Berger Journal: Am J Physiol Lung Cell Mol Physiol Date: 2020-04-15 Impact factor: 5.464