[abstract] PARTIAL REVERSAL OF RESPIRATORY CONTROL TIMING EFFECT OF O2 TOXICITY IN MAN DURING INTERMITTENT HYPEROXIA AT 2.0 ATA IN PREDICTIVE STUDIES VI.

Rubicon Research Repository/Manakin Repository

[abstract] PARTIAL REVERSAL OF RESPIRATORY CONTROL TIMING EFFECT OF O2 TOXICITY IN MAN DURING INTERMITTENT HYPEROXIA AT 2.0 ATA IN PREDICTIVE STUDIES VI.

Show full item record


Title: [abstract] PARTIAL REVERSAL OF RESPIRATORY CONTROL TIMING EFFECT OF O2 TOXICITY IN MAN DURING INTERMITTENT HYPEROXIA AT 2.0 ATA IN PREDICTIVE STUDIES VI.
Author: Gelfand, R; Clark, JM; Stevens, WC; Lambertsen, CJ
Abstract: During continuous hyperoxia the inspiratory duty cycle Ti/(Ti+Te) = %Ti decreases monotonically in time with progressively negative slopes at O2 pressures of 1.5, 2.0, 2.5, and 3.0 ATA (Gelfand et al, Undersea Biomed.Res. 16(Suppl):93,1989).In contrast, respiratory frequency does not change in a systematic manner with O2 exposure time and pressure. This,if respiratory rhythm and timing are governed by distinct CNS mechanisms (Feldman et al, Am. J. Phyiol. 259:R879-R866, 1990), decrement in %Ti may reflect progressive O2 poisoning of specific CNS neural mechanisms governing respiratory timing.Findings during two schedules of intermittent hyperoxia (60:15 and 30:30 min hyperoxia:min normoxia)at 2.0 ATA are summarized here.To minimize possible effects of pulmonary irritation on %Ti, observations only during periods when pulmonary symptoms were absent or mild are given.Compared to monotonic decrement during continuous hyperoxia, mean %Ti decrement for 60:15 (n=4) is delayed, reaches a nadir of about 10% below control at about 9.6 O2 exposure hrs, and partially recovers to about 8% decrement at 10.6 O2 hrs. During 30:/30 (n=4), %Ti decrement is also delayed, declines to a nadir (approx. 13% below control) at about 8 O2 hrs, and returns towards control reaching about 4% decrement at 14.5 O2 hrs. The delayed development of overt toxic effect during intermittency is expected. The unexpected reversal and partial recovery may reflect activation of latent antioxidant defenses and/or recovery processes. Supported in part by NMRDC contracts N00014-81-C-0826 and N0001488-K-0169, NASA Contract NAS9 17238 and the State of PA (Benjamin Franklin Partnership)
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held June 23-27, 1992. Hyatt Regency Bethesda Hotel, Bethesda, Maryland (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/7138
Date: 1992

Files in this item

Files Size Format View
abstract.txt 258bytes Text file View/Open

This item appears in the following Collection(s)

  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

Show full item record

Browse

My Account