Curtis Smith - Academia.edu (original) (raw)
Papers by Curtis Smith
Prepared for The Division of …, 2005
ABSTRACT
Journal of Applied Physiology, Mar 1, 1998
Effect of upper airway negative pressure on inspiratory drive during sleep. J. Appl. Physiol. 84(... more Effect of upper airway negative pressure on inspiratory drive during sleep. J. Appl. Physiol. 84(3): [1063][1064][1065][1066][1067][1068][1069][1070][1071][1072][1073][1074][1075] 1998.-To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on regulation of breathing, we studied four unanesthetized female dogs during wakefulness and sleep while they breathed via a fenestrated tracheostomy tube, which was sealed around the permanent tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration (Fen) was closed and exposing the UA to intrathoracic pressure changes, but not to flow changes, when Fen was open. During tracheal occlusion with Fen closed, inspiratory time (TI) increased during wakefulness, non-rapid-eyemovement (NREM) sleep and rapid-eye-movement (REM) sleep (155 Ϯ 8, 164 Ϯ 11, and 161 Ϯ 32%, respectively), reflecting the removal of inhibitory lung inflation reflexes. During tracheal occlusion with Fen open (vs. Fen closed): 1) the UA remained patent; 2) TI further increased during wakefulness and NREM (215 Ϯ 52 and 197 Ϯ 28%, respectively) but nonsignificantly during REM sleep (196 Ϯ 42%); 3) mean rate of rise of diaphragm EMG (EMGdi/TI) and rate of fall of tracheal pressure (Ptr/TI) were decreased, reflecting an additional inhibitory input from UA receptors; and 4) both EMGdi/TI and Ptr/TI were decreased proportionately more as inspiration proceeded, suggesting greater reflex inhibition later in the effort. Similar inhibitory effects of exposing the UA to negative pressure (via an open tracheal Fen) were seen when an inspiratory resistive load was applied over several breaths during wakefulness and sleep. These inhibitory effects persisted even in the face of rising chemical stimuli. This inhibition of inspiratory motor output is alinear within an inspiration and reflects the activation of UA pressuresensitive receptors by UA distortion, with greater distortion possibly occurring later in the effort. obstructive apnea; genioglossus; geniohyoid; diaphragm; tracheal occlusion; fenestrated tracheostomy tube 1064 UPPER AIRWAY REFLEXES DURING WAKEFULNESS AND SLEEP
As part of the Department of Energys Light Water Reactor Sustainability Program (LWRSP), tools an... more As part of the Department of Energys Light Water Reactor Sustainability Program (LWRSP), tools and methodology for risk-informed characterization of safety margin are being developed for use in supporting decision-making on plant life extension after the first license renewal. Beginning with the traditional discussion of margin in terms of a load (a physical challenge to system or component function) and
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM), 2006
Science and Technology of Nuclear Installations, 2015
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM), 2006
ABSTRACT
Following completion of the full-power operation probabilistic risk assessment (PRA) for the Adva... more Following completion of the full-power operation probabilistic risk assessment (PRA) for the Advanced Test Reactor (ATR), a shutdown PRA was initiated to provide coverage of operating configurations not previously analyzed. As has been typical, full-power operation was the primary focus of previous PRA activities; however, recent nuclear industry interest in non-full-power operation prompted the effort. Because of the many variables
Journal of applied physiology (Bethesda, Md. : 1985), 2000
The increase in systemic blood pressure after an obstructive apnea is due, in part, to sympatheti... more The increase in systemic blood pressure after an obstructive apnea is due, in part, to sympathetically mediated vasoconstriction. We questioned whether upper airway (UA) receptors could contribute reflexly to this vasoconstriction. Four unanesthetized dogs were studied during wakefulness and non-rapid-eye-movement (NREM) sleep. The dogs breathed via a fenestrated tracheostomy tube sealed around the tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration was closed and exposing the UA to negative inspiratory intrathoracic pressure when it was open. The blood pressure response to three UA perturbations was studied: 1) square-wave negative pressures sufficient to cause UA collapse with the fenestration closed during a mechanical hyperventilation-induced central apnea; 2) tracheal occlusion with the fenestration open vs. closed; and 3) high-frequency pressure oscillations (HFPO) with the fenestration closed. During NREM sleep, 1) blood ...
Journal of applied physiology (Bethesda, Md. : 1985), 1998
To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on... more To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on regulation of breathing, we studied four unanesthetized female dogs during wakefulness and sleep while they breathed via a fenestrated tracheostomy tube, which was sealed around the permanent tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration (Fen) was closed and exposing the UA to intrathoracic pressure changes, but not to flow changes, when Fen was open. During tracheal occlusion with Fen closed, inspiratory time (TI) increased during wakefulness, non-rapid-eye-movement (NREM) sleep and rapid-eye-movement (REM) sleep (155 +/- 8, 164 +/- 11, and 161 +/- 32%, respectively), reflecting the removal of inhibitory lung inflation reflexes. During tracheal occlusion with Fen open (vs. Fen closed): 1) the UA remained patent; 2) TI further increased during wakefulness and NREM (215 +/- 52 and 197 +/- 28%, respectively) but nonsignificantly...
Reliability Engineering & System Safety, 2008
The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analys... more The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analysis (PRRA) tools, dating back over 35 years. Evolving from mainframe-based software, the current state-of-the-practice has led to the creation of the SAPHIRE software. Currently, agencies such as the Nuclear Regulatory Commission, the National Aeronautics and Aerospace Agency, the Department of Energy, and the Department of Defense
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Prepared for The Division of …, 2005
ABSTRACT
Journal of Applied Physiology, Mar 1, 1998
Effect of upper airway negative pressure on inspiratory drive during sleep. J. Appl. Physiol. 84(... more Effect of upper airway negative pressure on inspiratory drive during sleep. J. Appl. Physiol. 84(3): [1063][1064][1065][1066][1067][1068][1069][1070][1071][1072][1073][1074][1075] 1998.-To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on regulation of breathing, we studied four unanesthetized female dogs during wakefulness and sleep while they breathed via a fenestrated tracheostomy tube, which was sealed around the permanent tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration (Fen) was closed and exposing the UA to intrathoracic pressure changes, but not to flow changes, when Fen was open. During tracheal occlusion with Fen closed, inspiratory time (TI) increased during wakefulness, non-rapid-eyemovement (NREM) sleep and rapid-eye-movement (REM) sleep (155 Ϯ 8, 164 Ϯ 11, and 161 Ϯ 32%, respectively), reflecting the removal of inhibitory lung inflation reflexes. During tracheal occlusion with Fen open (vs. Fen closed): 1) the UA remained patent; 2) TI further increased during wakefulness and NREM (215 Ϯ 52 and 197 Ϯ 28%, respectively) but nonsignificantly during REM sleep (196 Ϯ 42%); 3) mean rate of rise of diaphragm EMG (EMGdi/TI) and rate of fall of tracheal pressure (Ptr/TI) were decreased, reflecting an additional inhibitory input from UA receptors; and 4) both EMGdi/TI and Ptr/TI were decreased proportionately more as inspiration proceeded, suggesting greater reflex inhibition later in the effort. Similar inhibitory effects of exposing the UA to negative pressure (via an open tracheal Fen) were seen when an inspiratory resistive load was applied over several breaths during wakefulness and sleep. These inhibitory effects persisted even in the face of rising chemical stimuli. This inhibition of inspiratory motor output is alinear within an inspiration and reflects the activation of UA pressuresensitive receptors by UA distortion, with greater distortion possibly occurring later in the effort. obstructive apnea; genioglossus; geniohyoid; diaphragm; tracheal occlusion; fenestrated tracheostomy tube 1064 UPPER AIRWAY REFLEXES DURING WAKEFULNESS AND SLEEP
As part of the Department of Energys Light Water Reactor Sustainability Program (LWRSP), tools an... more As part of the Department of Energys Light Water Reactor Sustainability Program (LWRSP), tools and methodology for risk-informed characterization of safety margin are being developed for use in supporting decision-making on plant life extension after the first license renewal. Beginning with the traditional discussion of margin in terms of a load (a physical challenge to system or component function) and
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM), 2006
Science and Technology of Nuclear Installations, 2015
Proceedings of the Eighth International Conference on Probabilistic Safety Assessment & Management (PSAM), 2006
ABSTRACT
Following completion of the full-power operation probabilistic risk assessment (PRA) for the Adva... more Following completion of the full-power operation probabilistic risk assessment (PRA) for the Advanced Test Reactor (ATR), a shutdown PRA was initiated to provide coverage of operating configurations not previously analyzed. As has been typical, full-power operation was the primary focus of previous PRA activities; however, recent nuclear industry interest in non-full-power operation prompted the effort. Because of the many variables
Journal of applied physiology (Bethesda, Md. : 1985), 2000
The increase in systemic blood pressure after an obstructive apnea is due, in part, to sympatheti... more The increase in systemic blood pressure after an obstructive apnea is due, in part, to sympathetically mediated vasoconstriction. We questioned whether upper airway (UA) receptors could contribute reflexly to this vasoconstriction. Four unanesthetized dogs were studied during wakefulness and non-rapid-eye-movement (NREM) sleep. The dogs breathed via a fenestrated tracheostomy tube sealed around the tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration was closed and exposing the UA to negative inspiratory intrathoracic pressure when it was open. The blood pressure response to three UA perturbations was studied: 1) square-wave negative pressures sufficient to cause UA collapse with the fenestration closed during a mechanical hyperventilation-induced central apnea; 2) tracheal occlusion with the fenestration open vs. closed; and 3) high-frequency pressure oscillations (HFPO) with the fenestration closed. During NREM sleep, 1) blood ...
Journal of applied physiology (Bethesda, Md. : 1985), 1998
To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on... more To determine the effect of upper airway (UA) negative pressure and collapse during inspiration on regulation of breathing, we studied four unanesthetized female dogs during wakefulness and sleep while they breathed via a fenestrated tracheostomy tube, which was sealed around the permanent tracheal stoma. The snout was sealed with an airtight mask, thereby isolating the UA when the fenestration (Fen) was closed and exposing the UA to intrathoracic pressure changes, but not to flow changes, when Fen was open. During tracheal occlusion with Fen closed, inspiratory time (TI) increased during wakefulness, non-rapid-eye-movement (NREM) sleep and rapid-eye-movement (REM) sleep (155 +/- 8, 164 +/- 11, and 161 +/- 32%, respectively), reflecting the removal of inhibitory lung inflation reflexes. During tracheal occlusion with Fen open (vs. Fen closed): 1) the UA remained patent; 2) TI further increased during wakefulness and NREM (215 +/- 52 and 197 +/- 28%, respectively) but nonsignificantly...
Reliability Engineering & System Safety, 2008
The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analys... more The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analysis (PRRA) tools, dating back over 35 years. Evolving from mainframe-based software, the current state-of-the-practice has led to the creation of the SAPHIRE software. Currently, agencies such as the Nuclear Regulatory Commission, the National Aeronautics and Aerospace Agency, the Department of Energy, and the Department of Defense
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011
Springer Series in Reliability Engineering, 2011