scholarly journals Pharmacologically Induced Ventilatory Depression in the Postoperative Patient: A Sleep-Wake State-Dependent Perspective

2021 ◽  
Vol 132 (5) ◽  
pp. 1274-1286 ◽  
Author(s):  
Anthony G. Doufas ◽  
Toby N. Weingarten
Keyword(s):  
Postoperative Patient ◽  
State Dependent ◽  
Ventilatory Depression ◽  
Wake State

State-dependent effects of light-dark cycle on somatosensory and visual cortex EEG in rats

2005 ◽  
Vol 289 (4) ◽  
pp. R1083-R1089 ◽  
Author(s):  
Tadanobu Yasuda ◽  
Kyo Yasuda ◽  
Richard A. Brown ◽  
James M. Krueger
Keyword(s):  
Visual Cortex ◽  
Dark Period ◽  
Afferent Input ◽  
Light Period ◽  
Wave Band ◽  
Rapid Eye Movement Sleep ◽  
State Dependent ◽  
Eeg Power ◽  
Wake State ◽  
Constant Dark

Somatosensory (SSctx) and visual cortex (Vctx) EEG were evaluated in rats under a 12:12-h light-dark (LD) cycle and under constant light (LL) or constant dark (DD) in each sleep or wake state. Under LD conditions during light period, relative Vctx EEG slow-wave activity (SWA) was higher than that of the SSctx, whereas during dark period, relative Vctx EEG SWA was lower than in the SSctx. These effects were state specific, occurring only during non-rapid eye movement sleep (NREMS). Under LL conditions, the duration of REMS and NREMS during the period that would have been dark if the LD cycle had continued (subjective dark period) was greater than under LD conditions. DD conditions had little effect on the duration of NREMS and REMS. SSctx and Vctx EEG SWA were suppressed by LL during the subjective dark period; however, the degree of Vctx SWA suppression was smaller than that of the SSctx. DD conditions during the subjective light period enhanced SSctx SWA, whereas Vctx SWA was suppressed. Under LL conditions during the subjective dark period, Vctx EEG power was higher than that of the SSctx across a broad frequency range during NREMS, REMS, and wakefulness. During DD, SSctx EEG power during NREMS was higher than that of the Vctx in the delta wave band, whereas SSctx power during REMS and wakefulness was higher than that of the Vctx in frequencies higher than 8 Hz. We concluded that the SSctx and Vctx EEGs are differentially affected by light during subsequent sleep. Results provide support for the notion that regional sleep intensity is dependent on prior regional afferent input.

scholarly journals The retrotrapezoid nucleus and the neuromodulation of breathing

2020 ◽  
Author(s):  
Thiago S. Moreira ◽  
Cleyton R Sobrinho ◽  
Barbara Falquetto ◽  
Luiz M Oliveira ◽  
Janayna D Lima ◽  
...  
Keyword(s):  
Substance P ◽  
Adenosine Triphosphate ◽  
Target Cell ◽  
Cell Type ◽  
Retrotrapezoid Nucleus ◽  
State Dependent ◽  
Ventral Medullary Surface ◽  
Respiratory Homeostasis ◽  
Wake State ◽  
Specific Cluster

Breathing is regulated by a host of arousal and sleep-wake state-dependent neuromodulators in order to maintain respiratory homeostasis. Modulators such as acetylcholine, norepinephrine, histamine, serotonin (5-HT), adenosine triphosphate (ATP), substance P, somatostatin, bombesin, orexin, and leptin can serve complementary or off-setting functions depending on the target cell type and signalling mechanisms engaged. Abnormalities in any of these modulatory mechanisms can destabilize breathing, suggesting modulatory mechanisms are not overly redundant but rather work in concert to maintain stable respiratory output. The present review focuses on the modulation of a specific cluster of neurons located in the ventral medullary surface, named retrotrapezoid nucleus, that is activated by changes in tissue CO2/H+ and regulates several aspects of breathing, including inspiration and active expiration.

scholarly journals Mechanisms of nasal high flow on ventilation during wakefulness and sleep

2013 ◽  
Vol 114 (8) ◽  
pp. 1058-1065 ◽  
Author(s):  
Toby Mündel ◽  
Sheng Feng ◽  
Stanislav Tatkov ◽  
Hartmut Schneider
Keyword(s):  
Nasal Cavity ◽  
Tidal Volume ◽  
Respiratory Rate ◽  
Minute Ventilation ◽  
High Flow ◽  
Cavity Model ◽  
Ventilatory Responses ◽  
State Dependent ◽  
Inspiratory Resistance ◽  
Wake State

Nasal high flow (NHF) has been shown to increase expiratory pressure and reduce respiratory rate but the mechanisms involved remain unclear. Ten healthy participants [age, 22 ± 2 yr; body mass index (BMI), 24 ± 2 kg/m2] were recruited to determine ventilatory responses to NHF of air at 37°C and fully saturated with water. We conducted a randomized, controlled, cross-over study consisting of four separate ∼60-min visits, each 1 wk apart, to determine the effect of NHF on ventilation during wakefulness (NHF at 0, 15, 30, and 45 liters/min) and sleep (NHF at 0, 15, and 30 liters/min). In addition, a nasal cavity model was used to compare pressure/air-flow relationships of NHF and continuous positive airway pressure (CPAP) throughout simulated breathing. During wakefulness, NHF led to an increase in tidal volume from 0.7 ± 0.1 liter to 0.8 ± 0.2, 1.0 ± 0.2, and 1.3 ± 0.2 liters, and a reduction in respiratory rate ( fR) from 16 ± 2 to 13 ± 3, 10 ± 3, and 8 ± 3 breaths/min (baseline to 15, 30, and 45 liters/min NHF, respectively; P < 0.01). In contrast, during sleep, NHF led to a ∼20% fall in minute ventilation due to a decrease in tidal volume and no change in fR. In the nasal cavity model, NHF increased expiratory but decreased inspiratory resistance depending on both the cannula size and the expiratory flow rate. The mechanisms of action for NHF differ from those of CPAP and are sleep/wake-state dependent. NHF may be utilized to increase tidal breathing during wakefulness and to relieve respiratory loads during sleep.

Review of Flap Monitoring Technology in 2020

2020 ◽  
Vol 36 (06) ◽  
pp. 722-726
Author(s):  
Adam Jacobson ◽  
Oriana Cohen
Keyword(s):  
Head And Neck ◽  
Free Flap ◽  
Loss Rate ◽  
Early Recognition ◽  
Postoperative Patient ◽  
Free Flap Monitoring ◽  
Improved Outcomes ◽  
Vascular Compromise ◽  
Flap Monitoring ◽  
Multiple Levels

AbstractAdvances in free flap reconstruction of complex head and neck defects have allowed for improved outcomes in the management of head and neck cancer. Technical refinements have decreased flap loss rate to less than 4%. However, the potential for flap failure exists at multiple levels, ranging from flap harvest and inset to pedicle lay and postoperative patient and positioning factors. While conventional methods of free flap monitoring (reliant on physical examination) remain the most frequently used, additional adjunctive methods have been developed. Herein we describe the various modalities of both invasive and noninvasive free flap monitoring available to date. Still, further prospective studies are needed to compare the various invasive and noninvasive technologies and to propel innovations to support the early recognition of vascular compromise with the goal of even greater rates of flap salvage.

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