The veno‐arteriolar reflex in free skin flaps

Zoltie, N.; Young, Christopher J.; Faris, Irwin; Tan, Eugene

doi:10.1111/j.1475-097x.1989.tb00969.x

Cited by 14 publications

(20 citation statements)

References 8 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The VAR is mediated through a local mechanism (1,5,8,37), and the central nervous system is not necessary to evoke the response (20,25). This construct is supported by the observations that the VAR persists during acute spinal and sympathetic neural blockade proximal to the site of measurement (14,15,19,20,31,36), in denervated skin flaps (39) and in areas distal to the lesion in spinal cord transection patients (2,33,35). In the present study, subjects remained otherwise supine, and there were no changes in HR or arterial pressure during each test; thus changes in SkBF during each method were not related to central baroreflex mechanisms.…”

Section: Discussionmentioning

confidence: 66%

“…The arterial myogenic response related to increases in arterial pressure may also contribute to the changes in systemic vascular resistance during orthostasis (21,25,27,39) and to vasoconstriction during limb dependency (6,9,22). Although the exact signal transduction pathways underlining the myogenic response remain uncertain, it has been thought that vascular smooth muscle depolarization culminates in increased intracellular Ca 2ϩ levels with mechanically induced Ca 2ϩ entry via voltage-gated Ca 2ϩ channels and subsequent smooth muscle vasoconstriction (6,22).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Vasoconstriction during venous congestion: effects of venoarteriolar response, myogenic reflexes, and hemodynamics of changing perfusion pressure

Okazaki

Fu²,

Martini

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

We dissected the relative contribution of arteriovenous hemodynamics, the venoarteriolar response (VAR), and the myogenic reflex toward a decrease in local blood flow induced by venous congestion. Skin blood flow (SkBF) was measured in 12 supine subjects via laser-Doppler flowmetry 1) over areas of forearm and calf skin, in which the VAR was blocked by using eutectic mixture of local anesthetics (EMLA sites) and 2) over the contralateral forearm or calf skin (control sites), using two different techniques: limb dependency of 23-37 cm below the heart and cuff inflation to 40 mmHg. During limb dependency, SkBF decreased at the control sites, whereas it remained unchanged at the EMLA sites. In contrast, during cuff inflation, SkBF decreased at the control sites and also decreased at the EMLA sites. The percent change in SkBF from baseline was greater during cuff inflation than limb dependency at both the control sites and the EMLA sites. Estimated skin vascular resistance remained unchanged at the EMLA sites during cuff inflation, as well as limb dependency. Thus the decrease in SkBF during venous congestion with cuff inflation is not solely due to the cutaneous VAR but also to a reduction in local perfusion pressure. The VAR is therefore most specifically quantified by venous congestion induced by limb dependency, rather than cuff inflation. Finally, from both techniques, we calculated that during venous congestion induced by limb dependency (calf), approximately 45% of the nonbaroreflex vasoconstriction is induced by the VAR and approximately 55% by the myogenic reflex.

show abstract

Section: Discussionmentioning

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Vasoconstriction during venous congestion: effects of venoarteriolar response, myogenic reflexes, and hemodynamics of changing perfusion pressure

Okazaki

Fu²,

Martini

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

View full text Add to dashboard Cite

show abstract

“…The postural vasoconstrictor response of the fifth finger was not abolished by ulnar blockade. This response is probably mediated by myogenic autoregulation at the precapillary level [29,30], How ever evidence suggests that vasoconstriction in response to increased hydrostatic pressure is mediated by a local sympathetic axon reflex, which leads to vasoconstriction of the arterioles [31,32]. Local nerve blockade [33], in contrast to blockade at some distance [34] or sympathectomy [35], diminishes the postural vasoconstrictor response.…”

Section: Discussionmentioning

confidence: 99%

The influence of ulnar nerve blockade on skin microvascular blood flow*

Netten

Wollersheim

Gielen

et al. 1995

Eur J Clin Investigation

View full text Add to dashboard Cite

Abstract. Microvascular research is seriously ham pered by the great temporal and spatial variability of the measured skin blood flow and variation in sympa thetic vasomotor reflexes within and between persons. Therefore skin vasomotor reflexes were studied before and after ulnar nerve blockade within the same person, resulting in a temporal complete denervation of the fifth finger and partial denervation of the fourth finger. Skin temperature and laser Doppler flux (LDF) were registrated to measure predominantly arteriove nous shuntflow. Measurements were performed on the palmar tip of the second and fifth finger in nine healthy volunteers, at baseline, and during a sympa thetic reflex test (i.e. inspiratory gasp) and postural response test. Beat-to-beat digital blood pressure was recorded from the third and fourth finger by a Finapres device. Baseline capillary blood cell velocity (CBV) was measured at the nailfold of the second and the fifth finger. After ulnar blockade baseline skin temperature, LD F and CBV increased significantly, with respectively (mean ± SE) 3*2±0*9°C, 20*9 ±5*9 relative perfusion units and 0*79 ±0*40 m m " 1 s. The percentage LDF decrease of the fifth finger during inspiratory gasp was 48*2 ±5*3% before and 3*1 ±0-9% after blockade. The postural response test showed a decrease in LDF of the fifth finger with no significant difference before and after block ade, respectively 12*3 ±14*7% and 8*0±2*7%, while no difference was found in the increase in digital blood pressure in the denervated fourth finger compared to both the same finger before blockade and to the third non-blocked finger. It is concluded that ulnar nerve blockade enables the study of sympathetic skin vasomotor reflexes by comparison of a denervated and a non-denervated vascular bed within the same person. After ulnar blockade arteriovenous shunt flow as well as nutritional capillary blood flow increased significantly. Postural vasoconstrictor response is not abolished by ulnar blockade, suggesting that local regulatory mechanisms are more important.

show abstract

“…■ Key words skin blood flow · vasoconstriction · intradermal microdialysis · postural reflexes observations have clearly identified that the CVAR is not of central origin since it persists when central sympathetic outflow is prevented by spinal anesthesia, proximal sympathetic neural blockade, and in denervated skin flaps [13,14,27,32,35]. Application of local anesthetics abolishes the CVAR, strongly suggesting it is mediated by a local axon reflex [13,14,32].…”

Section: Introductionmentioning

confidence: 97%

Effect of local heating and vasodilation on the cutaneous venoarteriolar response

2004

View full text Add to dashboard Cite

The cutaneous venoarteriolar response (CVAR) is a local non-adrenergic vasoconstrictor reflex that is engaged via increases in local transmural pressure. The purpose of this study was to determine if local temperature alters the vasoconstrictor ability of the CVAR. Twelve (5 male, 7 female) subjects performed a CVAR maneuver at local temperatures of 30+/-1, 34, 38, and 42 degrees C. CVAR was also engaged after vasodilation via intradermal perfusion of sodium nitroprusside or the attenuation of local heating-induced vasodilation via intradermal perfusion of N(G)-nitro-L: -arginine methyl ester (L: -NAME) in five subjects (2 male, 3 female). CVAR was elicited by rapid cuff inflation to 45mmHg proximal to two dorsal forearm sites for 2 min in both protocols. Local heating caused a progressive increase in skin blood flow (8+/-1, 18+/-4, 43+/-11, and 78+/-2% maximal skin blood flow for 30+/-1, 34, 38, and 42 degrees C, respectively). Engagement of the CVAR decreased skin blood flow by 53+/-2, 57+/-3, and 51+/-4%, for 30+/-1, 34, and 38 degrees C, respectively. In contrast, local heating to 42 degrees C significantly attenuated the CVAR (16+/-11 %). Local administration of sodium nitroprusside during neutral temperature and L: -NAME during local heating also significantly attenuated the vasoconstrictor response of the CVAR by 27+/-8 and 38+/-4%, respectively. These data indicate that CVAR is attenuated at high (42 degrees C) local skin temperatures and that this attenuation is likely due to an effect of both local heating-induced vasodilation and a direct temperature effect.

show abstract

The veno‐arteriolar reflex in free skin flaps

Cited by 14 publications

References 8 publications

Vasoconstriction during venous congestion: effects of venoarteriolar response, myogenic reflexes, and hemodynamics of changing perfusion pressure

Vasoconstriction during venous congestion: effects of venoarteriolar response, myogenic reflexes, and hemodynamics of changing perfusion pressure

The influence of ulnar nerve blockade on skin microvascular blood flow*

Effect of local heating and vasodilation on the cutaneous venoarteriolar response

Contact Info

Product

Resources

About