PT  - JOURNAL ARTICLE
AU  - Jozsef Tolnai
AU  - Balint Ladjanszki
AU  - Ferenc Petak
AU  - Barna Babik
TI  - Capnogram phase III slope and dead space parameters: Comparison of main- and sidestream capnography techniques
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P2133
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P2133.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P2133.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - Rationale: Analyses of expired CO2 concentration by capnography provides useful non-invasive bedside information about heterogeneity of lung emptying and ventilation dead spaces. Although the recording of capnogram can be achieved by using mainstream (MS) and sidestream (SS) devices, the capnogram indices supplied by these approaches has not been systematically compared.Methods: To relate the parameters provided by these techniques, capnogram curves were recorded by using MS and SS techniques simultaneously in anaesthetized, mechanically ventilated patients undergoing elective heart surgery (n=39). Time capnography was used to assess phase III slope (SIII,T). Volumetric method was applied to estimate phase III slope (SIII,V), volume of CO2 eliminated per breath (VCO2), along with dead space parameters according to Fowler (VDF), Bohr (VDB) and Enghoff (VDE) methods. Partial pressure of CO2 in the arterial blood was also measured.Results: Excellent correlation and good agreement was observed in SIII,T measured by MS and SS techniques (table). However, SS significantly underestimated SIII,V and VCO2 and overestimated VDF, VDB and VDE.View this table:Relationships between MS and SS assessments of capnogram phase III slopes and dead spacesConclusions: Side stream time-capnography provides reliable estimates for the phase III slope, whereas application of a mainstream device is mandatory to assess volumetric parameters (slope, dead spaces and eliminated CO2 volume) reliably.Grant: TÁMOP-4.2.4.A/2-11/1-2012-0001, OTKA 81179.