title: Cyclic changes in arterial pulse during respiratory support revisited by Doppler echocardiography.
abstract: It has long been known that there are cyclic changes in arterial pressure during mechanical ventilation. They are caused by cyclic changes in both the right and left ventricular stroke output, occurring in opposite phases. As a result, arterial pulse pressure is increased during inspiration and decreased during expiration. A cyclic improvement in left ventricular systolic function could thus be expected during mechanical lung inflation. We tested this hypothesis in 31 septic patients who were mechanically ventilated in controlled mode by combining left ventricular measurements by transesophageal echocardiography with invasive arterial pressure recordings and Doppler analysis of pulmonary venous flow and right and left ventricular stroke volume. Lung inflation by tidal ventilation significantly improved left ventricular stroke volume (26 +/- 0.4 cm3/m2 [mean +/- SEM] vs. 22.3 +/- 0.4 cm3/m2 at end deflation). Beat-to-beat analysis of pulmonary venous flow velocity illustrated the boosting effect of lung inflation on pulmonary venous return. The beneficial effect of inspiration thus appeared directly related to a significant increase in left ventricular diastolic volume (60.3 +/- 1.5 cm3/m2 vs. 53.3 +/- 1.4 cm3/m2 at end-expiration) and to a lesser extent to an improved left ventricular ejection fraction. We concluded that the transient beneficial hemodynamic effect of tidal ventilation on the left ventricular pump is essentially mediated by an improved left ventricular filling.
authors.affiliation: University Hospital Ambroise Paré, Assistance Publique Hôpitaux de Paris, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Vieillard-Baron
authors.forename: Karim
authors.initials: K
authors.lastname: Chergui
authors.forename: Roch
authors.initials: R
authors.lastname: Augarde
authors.forename: Sebastien
authors.initials: S
authors.lastname: Prin
authors.forename: Bernard
authors.initials: B
authors.lastname: Page
authors.forename: Alain
authors.initials: A
authors.lastname: Beauchet
authors.forename: François
authors.initials: F
authors.lastname: Jardin
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D001795:Blood Pressure Determination; D002302:Cardiac Output; D015331:Cohort Studies; D017548:Echocardiography, Transesophageal; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D015588:Observer Variation; D011336:Probability; D012121:Respiration, Artificial / Q000379:methods*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000175:diagnosis / Q000628:therapy*; D012720:Severity of Illness Index; D013318:Stroke Volume