title: [Intraoperative changes in arterial end tidal CO2 partial pressure difference in interventions with constant ventilation-perfusion ratio].
abstract: During general anaesthesia, the endtidal CO2 pressure serves as an estimate of the arterial CO2 pressure to regulate the ventilator setting. Important arterial to end-tidal carbon dioxide tension differences (P(a-et)CO2) have been observed among patients undergoing procedures which have substantial impact on the ventilation-perfusion ratio (V/Q). Data on the P(a-et)CO2 for procedures in which the V/Q-ratio remains constant are lacking. Repeated measurements of P(a-et)CO2 in twelve patients with chronic obstructive lung disease (COLD) and nine pulmonary healthy patients undergoing jaw surgery were performed. The P(a-et)CO2 in the pulmonary healthy subjects (5.96 +/- 1.68 mmHg) was lower than in the COLD patients (9.05 +/- 3.49 mmHg) (p < 0.01). A clinically significant P(a-et)CO2 > or = 8 mmHg was observed in 52% of the measurements in patients with COLD compared with 11% in the pulmonary healthy subjects (p < 0.01). Both patient groups showed only minimal intraoperative changes of P(a-et)CO2. The deviation of all subsequent P(a-et)CO2 values from the initial P(a-et)CO2 was 2.17 +/- 1.52 mmHg in the pulmonary healthy patients and 2.02 +/- 1.49 mmHg in the patients with COLD (p = 0.76). Intraoperative changes of the P(a-et)CO2 are small during procedures with no major alterations of the V/Q ratio. For these procedures an initial measurement of the P(a-et)CO2 in patients with lung disease should be sufficient. In pulmonary healthy subjects the P(a-et)CO2 seems to be negligible.
authors.affiliation: Forschungsgruppe am Evangelischen Geriatrie Zentrum Berlin (EGZB). t.hillen@umds.ac.uk
authors.forename: T
authors.initials: T
authors.lastname: Hillen
authors.forename: R
authors.initials: R
authors.lastname: Sümpelmann
authors.forename: J M
authors.initials: JM
authors.lastname: Strauss
mesh_terms: D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D019647:Oral Surgical Procedures; D012016:Reference Values; D012307:Risk Factors; D013990:Tidal Volume / Q000502:physiology*; D014692:Ventilation-Perfusion Ratio / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
vernacular_title: Intraoperative Veränderungen der arterio-endtidalen CO2-Partialdruckdifferenz bei Eingriffen mit konstanten Ventilations-Perfusions-Verhältnissen.