title: Inspired gas relative humidity affects systemic to pulmonary bronchial blood flow in humans.
abstract: To our knowledge, the effects of humidity of inspired air on bronchial blood flow in humans are unknown. During total cardiopulmonary bypass, we measured systemic to pulmonary bronchial blood flow (Qbr[s-p]) which is the volume of blood accumulating into the left side of the heart in the absence of pulmonary and coronary flow. A cannula was introduced into the right upper pulmonary vein and advanced into the lowermost portion of the left side of the heart. From this cannula Qbr(s-p) was vented by gravity and measured. Inspired gas (10 L/min, endotracheal tube, 50 percent O2 + 50 percent N2O) relative humidity was less than 20 percent and greater than 85 percent in group A (n = 25) and in group B (n = 25), respectively. Mean (+/- SE) Qbr(s-p) was 40.7 +/- 0.06 ml/min or 1.32 +/- 0.12 ml/min (percent cardiac output) in group A and 21.7 +/- 1.8 ml/min or 0.68 +/- 0.06 ml/min in group B. These data indicate that under these conditions Qbr(s-p) is increased by dry gas lung inflation in humans.
authors.affiliation: Istituto di Cardiologia, Università di Milano, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Agostoni
authors.forename: V
authors.initials: V
authors.lastname: Arena
authors.forename: E
authors.initials: E
authors.lastname: Doria
authors.forename: G
authors.initials: G
authors.lastname: Susini
mesh_terms: D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D006813:Humidity; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation / Q000502:physiology*