title: Sequential V(A)/Q distributions in the normal rabbit by micropore membrane inlet mass spectrometry.
abstract: We developed micropore membrane inlet mass spectrometer (MMIMS) probes to rapidly measure inert-gas partial pressures in small blood samples. The mass spectrometer output was linearly related to inert-gas partial pressure (r(2) of 0.996-1.000) and was nearly independent of large variations in inert-gas solubility in liquid samples. We infused six inert gases into five pentobarbital-anesthetized New Zealand rabbits and used the MMIMS system to measure inert-gas partial pressures in systemic and pulmonary arterial blood and in mixed expired gas samples. The retention and excretion data were transformed into distributions of ventilation-to-perfusion ratios (V(A)/Q) with the use of linear regression techniques. Distributions of V(A)/Q were unimodal and broad, consistent with prior reports in the normal rabbit. Total blood sample volume for each VA/Q distribution was 4 ml, and analysis time was 8 min. MMIMS provides a convenient method to perform the multiple inert-gas elimination technique rapidly and with small blood sample volumes.
authors.affiliation: Department of Anesthesia, University of Pennsylvania, Philadelphia, Pennsylvania 19104-4283, USA. jbaumgar@mail.med.upenn.edu
authors.forename: J E
authors.initials: JE
authors.lastname: Baumgardner
authors.forename: I C
authors.initials: IC
authors.lastname: Choi
authors.forename: A
authors.initials: A
authors.lastname: Vonk-Noordegraaf
authors.forename: H F
authors.initials: HF
authors.lastname: Frasch
authors.forename: G R
authors.initials: GR
authors.lastname: Neufeld
authors.forename: B E
authors.initials: BE
authors.lastname: Marshall
mesh_terms: D000096:Acetone / Q000032:analysis; D018685:Anesthetics, Inhalation / Q000032:analysis; D000818:Animals; D001784:Blood Gas Analysis / Q000295:instrumentation* / Q000379:methods; D000077335:Desflurane; D004737:Enflurane / Q000032:analysis; D004986:Ether / Q000032:analysis; D005260:Female; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000032:analysis; D007726:Krypton / Q000032:analysis; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods; D008567:Membranes, Artificial; D005741:Noble Gases / Q000032:analysis; D010313:Partial Pressure; D011651:Pulmonary Artery / Q000502:physiology; D011817:Rabbits; D012680:Sensitivity and Specificity; D012995:Solubility; D013459:Sulfur Hexafluoride / Q000032:analysis; D014692:Ventilation-Perfusion Ratio
chemical_list: D018685:Anesthetics, Inhalation; D008567:Membranes, Artificial; D005741:Noble Gases; D004986:Ether; D000096:Acetone; D007726:Krypton; D004737:Enflurane; D000077335:Desflurane; D007530:Isoflurane; D013459:Sulfur Hexafluoride