Effects of lung volume on clearance of solutes from the air spaces of lungs
Several investigators have shown that the clearance rate of aerosolized 99mTc-labeled diethylenetriamine pentaacetate (DTPA, mol wt = 492, radius = 0.6 nm) from the air spaces of the lungs of humans and experimental animals increases with lung volume. To further investigate this phenomenon we performed a compartmental analysis of the 2-h clearance of DTPA from the lungs of anesthetized sheep using a new method to more accurately correct for the effects of DTPA recirculation. This analysis showed that the DTPA clearance in eight sheep ventilated with zero end-expired pressure was best described by a one-compartment model with a clearance rate of 0.42 +/- 0.15%/min. Ventilating eight sheep with an end-expired pressure of 10 cmH/sub 2/O throughout the study increased the end-expired volume 0.4 +/- 0.1 liter BTPS and created a clearance curve that was best described by a two-compartment model. In these sheep 56 +/- 16% of the DTPA cleared from the lungs at a rate of 7.9 +/- 2.9%/min. The remainder cleared at a rate similar to that measured in the sheep ventilated with zero end-expired pressure (0.35 +/- 0.18%/min). Additional control and lung inflation experiments were performed using /sup 99m/Tc-labeled human serum albumin (mol wt = 66,000, radius = 3.6 nm). In six control sheep ventilated with zero end-expired pressure the albumin clearance was best described by a one-compartment model with a clearance rate of 0.06 +/- 0.02%/min. The clearance rate in six sheep with increased lung volume was slightly larger (0.09 +/- 0.02, P less than 0.05) but was well described by a one-compartment model.
- Research Organization:
- Univ. of Texas Health Center, Tyler (USA)
- OSTI ID:
- 7190160
- Journal Information:
- J. Appl. Physiol.; (United States), Vol. 64:3
- Country of Publication:
- United States
- Language:
- English
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DTPA
LUNG CLEARANCE
LUNGS
DYNAMIC FUNCTION STUDIES
AEROSOLS
ALBUMINS
BIOLOGICAL MODELS
ISOMERIC NUCLEI
ORGANOMETALLIC COMPOUNDS
RESPIRATION
SHEEP
TECHNETIUM 99
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CHELATING AGENTS
CLEARANCE
COLLOIDS
DISPERSIONS
DOMESTIC ANIMALS
DRUGS
EXCRETION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RESPIRATORY SYSTEM
RUMINANTS
SOLS
TECHNETIUM ISOTOPES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
551001* - Physiological Systems- Tracer Techniques