29 August 2008
Capnometry in spontaneously breathing patients: the influence of chronic obstructive pulmonary disease and expiration maneuversManel LujanABCDEF, Elisa CanturriBCD, Amalia MorenoBC, Maribel ArranzBC, Laura VigilEF, Christian DomingoABCDEF
Med Sci Monit 2008; 14(9): CR485-492 :: ID: 867967
In spontaneously breathing patients, the differences between arterial PaCO2 and end-tidal CO2 (EtCO2) and the influence of bronchial obstruction have not clearly established.
Material and Method
This was a prospective observational study. Patients (n=120) were classified according to spirometric criteria into groups with normal, mild, moderate, and severe obstruction. Arterial blood gases and capnography were performed in two ways: with a tidal volume (Vt) and a non-forced maximal expiration maneuver. Pearson correlation coefficients (r) between PaCO2 and capnographic values were determined for the entire cohort and the subgroups. A concordance study was performed with Bland-Altman analysis.
Comparison of PaCO2 and EtCO2 measured at Vt showed a significant correlation (r=0.722, p<0.01) for the entire cohort, but with a significant mean infra-estimation: P(a-et)CO2=5.2+/-4.4 mmHg, p<0.05. Analysis of subgroups: At Vt, P(a-et)CO2 was 1.7+/-2.9 mmHg (p=ns) in patients with normal spirometry, being maximal in the group with greater obstruction (8.2+/-5.6 mmHg, p<0.05). At maximal expiration, the comparison between PaCO2 and EtCO2 showed a significant correlation (r=0.88, p<0.001), but a significant lack of concordance for the entire cohort (P(a-et)CO2=-4.8+/-4 mmHg, p<0.05) and subgroups. Finally, comparison of PaCO2 and mean EtCO2 values showed a significant correlation (r=0.74, p<0.001) and concordance (P(a-et)CO2= 0.2+/-3.3 mmHg, p=ns) for the entire cohort and subgroups.
Capnographic results at Vt are accurate predictors of true PaCO2 only in patients without bronchial obstruction. The maneuvers of slow maximal expiration overestimate PaCO2 in all groups. The best concordance was obtained comparing PaCO2 with mean EtCO2.
Keywords: Respiration, Tidal Volume, Pulmonary Disease, Chronic Obstructive - physiopathology, Prospective Studies, Partial Pressure, Exhalation, Statistics as Topic, Carbon Dioxide - blood, Capnography - methods, Blood Gas Analysis
01 May 2022 : EditorialEditorial: Cardiovascular Complications at One Year After SARS-CoV-2 Infection are Independent of Underlying Cardiovascular Risk Factors or Severity of COVID-19
Med Sci Monit 2022; 28:e937048
04 May 2022 : Clinical ResearchEffects of Wearing Face Masks on Exercise Capacity and Ventilatory Anaerobic Threshold in Healthy Subjects ...
Med Sci Monit In Press; DOI: 10.12659/MSM.936069
27 May 2022 : Clinical ResearchFactors Associated with Falls During Hospitalization for Coronavirus Disease 2019 (COVID-19)
Med Sci Monit 2022; 28:e936547
27 May 2022 : Clinical ResearchPrognostic Significance of Preoperative Integrated Liver Inflammatory Score in Patients with Hepatocellular...
Med Sci Monit In Press; DOI: 10.12659/MSM.937005
25 May 2022 : Review articleNarrative Review of the Mechanism of Hip Prosthesis Dislocation and Methods to Reduce the Risk of Dislocation
Med Sci Monit In Press; DOI: 10.12659/MSM.935665
24 May 2022 : Clinical ResearchRemimazolam Tosilate Sedation with Adjuvant Sufentanil in Chinese Patients with Liver Cirrhosis Undergoing ...
Med Sci Monit In Press; DOI: 10.12659/MSM.936580
Most Viewed Current Articles
30 Dec 2021 : Clinical ResearchRetrospective Study of Outcomes and Hospitalization Rates of Patients in Italy with a Confirmed Diagnosis o...
Med Sci Monit 2021; 27:e935379
08 Mar 2022 : Review articleA Review of the Potential Roles of Antioxidant and Anti-Inflammatory Pharmacological Approaches for the Man...
Med Sci Monit 2022; 28:e936292
01 Nov 2020 : Review articleLong-Term Respiratory and Neurological Sequelae of COVID-19
Med Sci Monit 2020; 26:e928996