Relationship of end-expiratory pressure, lung volume, and /sup 99m/Tc-DTPA clearance

Journal Article · Thu Oct 01 04:00:00 EDT 1987 · J. Appl. Physiol.; (United States)

OSTI ID:5556734

Cooper, J A; van der Zee, H; Line, B R; Malik, A B

We investigated the dose-response effect of positive end-expiratory pressure (PEEP) and increased lung volume on the pulmonary clearance rate of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA). Clearance of lung radioactivity was expressed as percent decrease per minute. Base-line clearance was measured while anesthetized sheep (n = 20) were ventilated with 0 cmH/sub 2/O end-expiratory pressure. Clearance was remeasured during ventilation at 2.5, 5, 10, 15, or 20 cmH/sub 2/O PEEP. Further studies showed stepwise increases in functional residual capacity (FRC) (P less than 0.05) measured at 0, 2.5, 5, 10, 15, and 20 cmH/sub 2/O PEEP. At 2.5 cmH/sub 2/O PEEP, the clearance rate was not different from that at base line (P less than 0.05), although FRC was increased from base line. Clearance rate increased progressively with increasing PEEP at 5, 10, and 15 cmH/sub 2/O (P less than 0.05). Between 15 and 20 cmH/sub 2/O PEEP, clearance rate was again unchanged, despite an increase in FRC. The pulmonary clearance of aerosolized /sup 99m/Tc-DTPA shows a sigmoidal response to increasing FRC and PEEP, having both threshold and maximal effects. This relationship is most consistent with the hypothesis that alveolar epithelial permeability is increased by lung inflation.

• Research Organization: Albany Medical College of Union Univ., NY
• OSTI ID: 5556734
• Journal Information: J. Appl. Physiol.; (United States), Journal Name: J. Appl. Physiol.; (United States) Vol. 63:4; ISSN JAPYA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CHELATING AGENTS
CLEARANCE
DOMESTIC ANIMALS
DOSE-RESPONSE RELATIONSHIPS
DRUGS
DTPA
DYNAMIC FUNCTION STUDIES
EPITHELIUM
EXCRETION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LUNG CLEARANCE
LUNGS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
ORGANS
PERMEABILITY
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RESPIRATION
RESPIRATORY SYSTEM
RUMINANTS
SHEEP
TECHNETIUM 99
TECHNETIUM ISOTOPES
TISSUES
TRACER TECHNIQUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES