title: Variations in pulmonary artery occlusion pressure to estimate changes in pleural pressure.
abstract: A readily available assessment of changes in pleural pressure would be useful for ventilator and fluid management in critically ill patients. We examined whether changes in pulmonary artery occlusion pressure (Ppao) adequately reflect respiratory changes in pleural pressure as assessed by changes in intraesophageal balloon pressure (Peso). We studied patients who had a pulmonary catheter and esophageal balloon surrounding a nasogastric tube as part of their care (n=24). We compared changes in Ppao (dPpao) to changes in Peso (dPeso) by Bland-Altman and regression analysis. Adequacy of balloon placement was assessed by performing Mueller maneuvers and adjusting the position to achieve a ratio of dPeso to change in tracheal pressure (dPtr) of 0.85 or higher. This was achieved in only 14 of the 24 subjects. We also compared dCVP to dPeso. The dPpao during spontaneous breaths and positive pressure breaths gave a good estimate of Peso but generally underestimated dPeso (bias=2.2 +8.2 and -3.9 cmH2O for the whole group). The dCVP was not as good a predictor (bias=2.9 +10.3 and -4.6). In patients who have a pulmonary artery catheter in place dPpao gives a lower estimate of changes in pleural pressure and may be more reliable than dPeso. The dCVP is a less reliable predictor than changes in pleural pressure.
authors.affiliation: Intensive Care Unit, Hôpital du Sacré Coeur de Montréal, 5400 Gouin Blvd. W, H4J 1C5 Montreal, Canada.
authors.forename: Patrick
authors.initials: P
authors.lastname: Bellemare
authors.forename: Peter
authors.initials: P
authors.lastname: Goldberg
authors.forename: Sheldon A
authors.initials: SA
authors.lastname: Magder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D001795:Blood Pressure Determination / Q000379:methods*; D006328:Cardiac Catheterization; D016638:Critical Illness; D004940:Esophageal Stenosis / Q000628:therapy; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000503:physiopathology*; D011792:Quebec; D012121:Respiration, Artificial