Effects of Sevoflurane Anesthesia on Carotid-Cardiac Baroreflex Responses in Humans

Umehara, Shino; Tanaka, Makoto; Nishikawa, Toshiaki

doi:10.1213/01.ane.0000183651.10514.9a

Cited by 18 publications

(8 citation statements)

References 40 publications

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“…NREMS (Table 4), suggesting differences in sleep microstructure such as the cyclic alternating pattern (17). In contrast, BRS is reported to decrease in anesthesia with respect to wakefulness (36). This difference emphasizes that although deep NREMS and anesthesia share some remarkably similar physiological traits (22), they may not be comparable in terms of cardiovascular control.…”

Section: Time Shifts Corresponding To the Maximum And Minimum Valuementioning

confidence: 88%

Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects

Silvani¹,

Grimaldi²,

Vandi³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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Cortelli P. Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects. We investigated whether in human subjects, the pattern of coupling between the spontaneous fluctuations of heart period (HP) and those of systolic blood pressure (SBP) differs among wake-sleep states. Polysomnographic recordings and finger blood pressure measurements were performed for 48 h in 15 nonobese adults without sleep-disordered breathing. The cross-correlation function (CCF) between the fluctuations of HP and SBP at frequencies Ͻ0.15 Hz was computed during quiet wakefulness (QW), light (stages 1 and 2) and deep (stages 3 and 4) nonrapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS). A positive correlation between HP and the previous SBP values, which is the expected result of baroreflex feedback control, was observed in the sleep states but not in QW. In deep NREMS, the maximum CCF value was significantly higher than in any other state, suggesting the greatest baroreflex contribution to the coupling between HP and SBP. A negative correlation between HP and the subsequent SBP values was also observed in each state, consistent with the mechanical feed-forward action of HP on SBP and with central autonomic commands. The contribution of these mechanisms to the coupling between HP and SBP, estimated from the minimum CCF value, was significantly lower in deep NREMS than either in light NREMS or QW. These results indicate that the pattern of coupling between HP and SBP at low frequencies differs among wake-sleep states in human subjects, with deep NREMS entailing the highest feedback contribution of the baroreflex and a low effectiveness of feed-forward mechanisms.feedback and feed-forward mechanisms; baroreflex; central autonomic commands; cross-correlation analysis; sequence technique THE PATTERN OF COUPLING BETWEEN the spontaneous fluctuations of heart period (HP) and those of blood pressure indicates the contribution of different mechanisms to cardiovascular control during real-life behavior. In particular, a positive correlation between HP and the previous pressure values is the expected result of the arterial baroreflex, which acts as a delayed negative-feedback control (37). In turn, the fluctuations of HP may alter cardiac output, eliciting pressure fluctuations that are negatively correlated with them. Central autonomic commands (15) cause opposite changes in HP and vascular resistance (13), thereby apparently enhancing this feed-forward interaction.In animal models, the pattern of coupling between HP and blood pressure suggests a variable contribution of central and baroreflex mechanisms to cardiovascular control in different wake-sleep states (33,34,39). The baroreflex contribution appears most prominent during quiet sleep in lambs (33) and during nonrapid-eye-movement sleep (NREMS) in rats (34,39). On the other hand, in rapid-eye-movement sleep (REMS), the contribution of feed-forward mechanisms prevails in rats due to central autonomic commands (6,34,39), which manifest a...

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Section: Time Shifts Corresponding To the Maximum And Minimum Valuementioning

confidence: 88%

Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects

Silvani¹,

Grimaldi²,

Vandi³

et al. 2008

American Journal of Physiology-Regulatory, Integrative and Comp

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show abstract

“…While some authors report baroreflex regulation of heart rate using mean carotid sinus pressure as the independent variable (Smith et al 2003; Matsukawa et al 2006), others use systolic carotid arterial pressure (Halliwill & Minson, 2002), because heart rate correlates closely with systolic pressure but not with diastolic pressure (Sundlöf & Wallin, 1977; Rudas et al 1999). In another study, the authors plotted the relationship between heart period and systolic carotid sinus pressure (Umehara et al 2006). In order to compare their results with other studies, Linnarsson et al (2006) analysed their data twice: once as the relationship between heart rate and mean arterial pressure, and then as the relationship beween pulse interval and systolic pressure.…”

Section: Discussionmentioning

confidence: 99%

The influence of heart rate on baroreceptor fibre activity in the carotid sinus and aortic depressor nerves of the rabbit

Barrett

Bolter

2006

Experimental Physiology

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The arterial baroreceptors and their afferent fibres provide the sensory arm of the reflex that regulates systemic arterial pressure. We have examined whether the relationship between mean baroreceptor discharge and mean arterial pressure is altered when heart rate changes. Experiments were performed on pentobarbitone-anaesthetized rabbits. We recorded the activity of single and multifibre preparations of the carotid sinus (CSN) and aortic depressor nerves (ADN). Data were collected under control conditions and while heart rate was increased by ∼30-35% by right atrial pacing. Baroreceptor regions were exposed to ramps of pressure (from ∼25 to 140 mmHg, at ∼0.5-1 mmHg s −1 ), generated by inflation and deflation of cuffs placed around the inferior vena cava and descending thoracic aorta. Response curves relating baroreceptor discharge to mean pressure were constructed and fitted with third-order polynomial expressions. To provide a measure of an effect of an increase in heart rate on the response curve in the region of the normal operating pressure, we calculated the position of the test response curve relative to the position of the control curve at 90 mmHg (δBP 90 ). For the ADN, the activity of single fibres (presumptive myelinated fibres) was unaffected by increasing heart rate (δBP 90 = +0.1 ± 1.0 mmHg), while single fibres in the CSN showed a small increase in activity (δBP 90 = −1.5 ± 0.3 mmHg). In multifibre preparations there was a small increase in activity that may be attributable to additional activity in unmyelinated fibres (ADN, δBP 90 = −3.4 ± 1.2 mmHg; CSN, δBP 90 = −5.2 ± 0.9 mmHg). We conclude that the mean discharge of arterial baroreceptors remains a reliable index of mean arterial pressure in the presence of substantial changes in heart rate.

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“…Finally, this study was performed on anaesthetized animals. It is known that anaesthesia both depresses autonomic reflexes (Ebert et al 1995;Umehara et al 2006) and has an anti-inflammatory action (Kotanidou et al 1996;Fuentes et al 2005;Rodriguez-Gonzalez et al 2013). Both these factors are likely to have influenced our results quantitatively.…”

Section: Limitationsmentioning

confidence: 92%

Reflex control of inflammation by sympathetic nerves, not the vagus

Martelli

Yao

McKinley

et al. 2014

The Journal of Physiology

198

242

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Key pointsr It is believed that the CNS controls inflammation via the autonomic nervous system, but the strength of this action and the neural pathways responsible are unclear.r In anaesthetized rats we measured the inflammatory response to lipopolysaccharide (LPS, 60 μg kg −1 , I.V.) by plasma tumour necrosis factor α (TNFα) levels 90 min later.r Bilateral section of the splanchnic sympathetic nerves before LPS treatment resulted in a 5-fold increase in the plasma TNFα response, but bilateral vagotomy had no effect.r LPS treatment strongly increased efferent activity in the splanchnic sympathetic nerve and its splenic branch; vagotomy did not affect this.r These results show that, besides directly stimulating inflammation, LPS engages a powerful anti-inflammatory reflex that can inhibit the plasma TNFα response by 80%.r The reflex efferent arm is in the splanchnic sympathetic nerves; the vagi play no part.Abstract We investigated a neural reflex that controls the strength of inflammatory responses to immune challenge -the inflammatory reflex. In anaesthetized rats challenged with intravenous lipopolysaccharide (LPS, 60 μg kg −1 ), we found strong increases in plasma levels of the key inflammatory mediator tumour necrosis factor α (TNFα) 90 min later. Those levels were unaffected by previous bilateral cervical vagotomy, but were enhanced approximately 5-fold if the greater splanchnic sympathetic nerves had been cut. Sham surgery had no effect, and plasma corticosterone levels were unaffected by nerve sections, so could not explain this result. Electrophysiological recordings demonstrated that efferent neural activity in the splanchnic nerve and its splenic branch was strongly increased by LPS treatment. Splenic nerve activity was dependent on inputs from the splanchnic nerves: vagotomy had no effect on the activity in either nerve.Together, these data demonstrate that immune challenge with this dose of LPS activates a neural reflex that is powerful enough to cause an 80% suppression of the acute systemic inflammatory response. The efferent arm of this reflex is in the splanchnic sympathetic nerves, not the vagi as previously proposed. As with other physiological responses to immune challenge, the afferent pathway is presumptively humoral: the present data show that vagal afferents play no measurable part. Because inflammation sits at the gateway to immune responses, this reflex could play an important role in immune function as well as inflammatory diseases.

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Effects of Sevoflurane Anesthesia on Carotid-Cardiac Baroreflex Responses in Humans

Cited by 18 publications

References 40 publications

Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects

Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects

The influence of heart rate on baroreceptor fibre activity in the carotid sinus and aortic depressor nerves of the rabbit

Reflex control of inflammation by sympathetic nerves, not the vagus

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