Acetazolamide slows VA/Q matching after changes in regional blood flow

Erik  R Swenson; Michael M Graham; Michael P Hlastala

doi:10.1152/jappl.1995.78.4.1312

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Acetazolamide slows VA/Q matching after changes in regional blood flow

Journal article

Peer reviewed

Acetazolamide slows VA/Q matching after changes in regional blood flow

Erik R Swenson, Michael M Graham and Michael P Hlastala

Journal of applied physiology (1985), Vol.78(4), pp.1312-1318

04/1995

DOI: 10.1152/jappl.1995.78.4.1312

PMID: 7615438

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Abstract

Inhibition of carbonic anhydrase (CA) by acetazolamide increases ventilation-perfusion (VA/Q) heterogeneity (E. R. Swenson, H. T. Robertson, and M. P. Hlastala. J. Clin. Invest. 92: 702-709, 1993), possibly because of slowing of CO2/H(+)-dependent mechanisms of VA/Q matching with temporal fluctuations of regional ventilation and perfusion. To study this concept, we imposed abrupt changes in regional perfusion by lobar or left main pulmonary artery occlusions (PAOs) in anesthetized mechanically ventilated dogs before and after CA inhibition (20 mg/kg iv acetazolamide). The rate of ventilation redistribution and change in VA/Q distributions with changes in perfusion were measured by planar gamma imaging of the lungs during continuous inhalation of 81mKr gas ventilation scanning and the multiple inert-gas elimination technique. PAO for 5 min caused regional Kr activity to fall by 30 +/- 5% (SD) with a half time (t1/2) of 75 +/- 10 s. With release of the occlusion, counts returned to baseline with t1/2 of 79 +/- 12 s. Acetazolamide increased these respective t1/2 values (161 +/- 16 and 180 +/- 17 s). Consistent with these kinetics, VA/Q mismatch was greater with lobar PAO at 2 min but not at 10 min with CA inhibition compared with that caused by lobar PAO alone. Cyclical lobar PAO and release (10 cycles of 1-min occlusion and 1-min release) caused more VA/Q heterogeneity during CA inhibition. The arterial-to-alveolar inert-gas area difference rose minimally from 0.18 to 0.23 (P < 0.05) with cyclical PAO and from 0.24 to 0.48 (P < 0.01) after CA inhibition.

Acetazolamide - pharmacology

Lung - physiopathology

Pulmonary Artery - physiopathology

Pulmonary Artery - drug effects

Respiration - physiology

Carbonic Anhydrases - metabolism

Lung - enzymology

Animals

Regional Blood Flow - drug effects

Lung - drug effects

Respiration - drug effects

Ventilation-Perfusion Ratio - drug effects

Dogs

Ventilation-Perfusion Ratio - physiology

Respiratory Function Tests

Arterial Occlusive Diseases - physiopathology

Lung - blood supply

Carbonic Anhydrases - drug effects

Blood Flow Velocity - drug effects

Disease Models, Animal

Details

Title: Subtitle: Acetazolamide slows VA/Q matching after changes in regional blood flow
Creators: Erik R Swenson - Medical Service, Veteran Affairs Medical Center, Seattle, Washington 98108, USA
Michael M Graham
Michael P Hlastala
Resource Type: Journal article
Publication Details: Journal of applied physiology (1985), Vol.78(4), pp.1312-1318
DOI: 10.1152/jappl.1995.78.4.1312
PMID: 7615438
NLM abbreviation: J Appl Physiol (1985)
ISSN: 8750-7587
eISSN: 1522-1601
Publisher: United States
Grant note: HL-12174 / NHLBI NIH HHS HL-45571 / NHLBI NIH HHS
Language: English
Date published: 04/1995
Academic Unit: Radiology; Radiation Oncology
Record Identifier: 9984047867302771

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