title: Effect of PEEP on regional ventilation and perfusion in the mechanically ventilated preterm lamb.
abstract: Improvement of gas exchange through closer matching of regional ventilation (V) and lung perfusion (Q) with the application of positive end-expiratory pressure (PEEP) was evaluated in vivo in six mechanically ventilated preterm lambs (107-126 days/145 days gestation). Changes in V and Q were determined from in vivo scintigraphic measurements in four lung regions with inhaled radioactive 81mKr, and infused 81mKr/dextrose and/or [99mTc]MAA as PEEP was applied at 2, 4, and 6 cm H2O in each animal. Dynamic compliance varied between 0.02 and 0.40 ml/cm H2O, which was consistent with surfactant deficiency. As PEEP was increased, the regional distribution of Q shifted from the rostral to the caudal lung regions (p less than 0.02 to less than 0.05), while that of V remained unchanged. Regional V/Q matching improved together with a trend towards improvement of arterial blood gases as PEEP was increased from 2 to 4 cm H2O. Pulmonary scintigraphy offers a noninvasive methodology for the quantitative assessment of regional V and Q matching in preterm lambs and may be clinically applicable to ventilated neonates.
authors.affiliation: Department of Pediatrics, North Shore University Hospital, Cornell University Medical College, Manhasset, New York 11030.
authors.forename: J S
authors.initials: JS
authors.lastname: Schlessel
authors.forename: H
authors.initials: H
authors.lastname: Susskind
authors.forename: D D
authors.initials: DD
authors.lastname: Joel
authors.forename: A
authors.initials: A
authors.lastname: Bossuyt
authors.forename: W H
authors.initials: WH
authors.lastname: Harrold
authors.forename: I
authors.initials: I
authors.lastname: Zanzi
authors.forename: A D
authors.initials: AD
authors.lastname: Chanana
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D007727:Krypton Radioisotopes; D008168:Lung / Q000000981:diagnostic imaging; D011175:Positive-Pressure Respiration; D011877:Radionuclide Imaging; D012756:Sheep; D013668:Technetium Tc 99m Aggregated Albumin; D014692:Ventilation-Perfusion Ratio
chemical_list: D007727:Krypton Radioisotopes; D013668:Technetium Tc 99m Aggregated Albumin