Calcolo del rapporto spazio morto/volume corrente nello scompenso cardiaco durante esercizio.

Translated title of the contribution: Measurement of dead space/tidal volume ratio during exercise in patients with heart failure

Research output: Contribution to journalArticlepeer-review

Abstract

Dead space (VD)/tidal volume (VT) ratio is an indirect index of ventilation/perfusion matching. Therefore, it is currently evaluated in patients with congestive heart failure to detect the organ system limiting the exercise tolerance. The VD/VT calculation requires measurement of arterial CO2 partial pressure (PaCO2). For practical reasons, the software of most metabolic carts substitutes the PaCO2 with the end-expiratory CO2 (PETCO2) or the PJCO2 (calculated as PJCO2 = 5.5 +/- 0.9 PETCO2-2.1 VT). Nonetheless, the applicability of these methods in congestive heart failure is unknown. We compared in 63 patients with congestive heart failure 326 measurements of PaCO2 versus PETCO2 and PJCO2 and VD/VT measured with PaCO2 versus VD/VT estimated with PETCO2 (estimation 1) or PJCO2 (estimation 2). Comparisons were made at rest (Phase 1), during submaximal exercise (Phase 2), and at peak exercise (Phase 3). We found a strong correlation, but not an identity, between PaCo2 and PETCO2 (PaCO2 = 7.25 +/- 0.80 PETCO2, r = 0.84; p <0.0001); similarly for PaCO2 and PETCO2. Several observations were out of 95% confidence interval, and some measurements exceeded mean +/- 2 SD when the differences between PaCo2 and PETCO2 or PJCO2 were plotted against the averages from the two (Bland and Altman method). Measured VD/VTs also strongly correlated with the estimated ones (VD/VT measured = -0.03 +/- 1.11 VD/VT estimated 1 r = 0.90; p <0.0001 e VD/VT measured = 0.03 +/- 0.92 VD/VT estimated 2 r = 0.90; p <0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Translated title of the contributionMeasurement of dead space/tidal volume ratio during exercise in patients with heart failure
Original languageItalian
Pages (from-to)167-172
Number of pages6
JournalCardiologia
Volume40
Issue number3
Publication statusPublished - Mar 1995

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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