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Doppler Probe (doppler + probe)

Distribution by Scientific Domains

Medical Sciences	85%

Selected Abstracts

Postoperative monitoring of lower limb free flaps with the Cook,Swartz implantable Doppler probe: A clinical trial

MICROSURGERY, Issue 5 2010
B.Med.Sc., P.G.Dip.Surg.Anat., Ph.D., Warren M. Rozen M.B.B.S.
Background: Free flaps to the lower limb have inherently high venous pressures, potentially impairing flap viability, which may lead to limb amputation if flap failure ensues. Adequate monitoring of flap perfusion is thus essential, with timely detection of flap compromise able to potentiate flap salvage. While clinical monitoring has been popularized, recent use of the implantable Doppler probe has been used with success in other free flap settings. Methods: A comparative study of 40 consecutive patients undergoing microvascular free flap reconstruction of lower limb defects was undertaken, with postoperative monitoring achieved with either clinical monitoring alone or the use of the Cook-Swartz implantable Doppler probe. Results: The use of the implantable Doppler probe was associated with salvage of 2/2 compromised flaps compared to salvage of 2/5 compromised flaps in the group undergoing clinical monitoring alone (salvage rate 100% vs. 40%, P = 0.28). While not statistically significant, this was a strong trend toward an improved flap salvage rate with the use of the implantable Doppler probe. There were no false positives or negatives in either group. One flap loss in the clinically monitored group resulted in limb amputation (the only amputation in the cohort). Conclusion: A trend toward early detection and salvage of flaps with anastomotic insufficiency was seen with the use of the Cook,Swartz implantable Doppler probe. These findings suggest a possible benefit of this technique as a stand-alone or adjunctive tool in the clinical monitoring of free flaps, with further investigation warranted into the broader application of these devices. © 2009 Wiley-Liss, Inc. Microsurgery 30:354,360, 2010. [source]

The effect of nitrous oxide on cerebral blood flow velocity in children anesthetized with propofol

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2003
E. Wilson-Smith
Background: Propofol for maintenance of anesthesia by continuous infusion is gaining popularity for use in pediatric patients. Nitrous oxide (N2O) has been shown to increase cerebral blood flow velocity (CBFV) in both children and adults. To determine the effects of N2O on middle cerebral artery blood flow velocity (Vmca) during propofol anesthesia in children, Vmca was measured with and without N2O using transcranial Doppler (TCD) sonography. Methods: Thirty ASA I or II children aged 18 months to 6 years undergoing elective urological surgery were enrolled. Anesthesia comprised propofol aimed at producing an estimated steady-state serum concentration of 3 µg·ml,1 and a caudal epidural block. A transcranial Doppler probe was used to measure middle cerebral artery blood flow velocity. Each patient was randomized to receive a sequence of either Air/N2O/Air or N2O/Air/N2O in 35% oxygen. Fifteen min after each change in the N2O concentration, three measurements of cerebral blood flow velocity, blood pressure and heart rate were recorded. Ventilatory parameters and EtCO2 were kept constant throughout the study period. Results: CBFV increased by 12.4% when air was replaced by N2O, and returned to baseline when N2O was subsequently removed. There was a 14% decrease in CBFV when N2O was replaced with air, which increased to baseline when air was subsequently replaced with N2O. Mean heart rate and blood pressure remained constant throughout the study period. Conclusion: The effects of nitrous oxide on CBFV are preserved in children during propofol anesthesia. [source]

Use of the Esophageal Doppler Machine to help guide the intraoperative management of two children with pheochromocytoma

PEDIATRIC ANESTHESIA, Issue 8 2006
HENRIK HACK BSc MBBS MRCP FRCA
Summary The anesthetic management of pheochromocytoma has been based upon the intraoperative control of blood pressure and fluid balance following adequate preoperative preparation. This can be difficult, especially in the presence of significant comorbidity such as cardiac or renal dysfunction. Two cases of children with pheochromocytoma are reported where the introperative management of fluid balance and blood pressure control were guided by measurement of changes in descending aortic blood flow using an esophageal Doppler probe. The advantages of such a technique compared with more invasive monitors are discussed. [source]

Intra-arterial Effects of Cisplatin on Microvascular Anastomoses in the Rat Model

THE LARYNGOSCOPE, Issue 8 2002
Deepak Gurushanthaiah MD
Abstract Objective To evaluate the patency of microvascular anastomoses in arteries exposed to intra-arterial cisplatin. Study Design Animal model. Methods The common iliac artery of 15 rats was injected with 150 mg/m2 cisplatin. Five rats were injected with the same volume of saline serving as physiological controls. The ipsilateral femoral artery was transected and anastomosed using microsurgical technique within 3 to 5 days. A Doppler probe was used before and after the anastomosis to assess blood flow. The vessel was re-examined on postoperative day 5. Pulsatile blood flow and the presence or absence of a Doppler signal was recorded at this time. Vessels were harvested to include the anastomosis site and fixed for histological evaluation. The contralateral femoral artery was also harvested for comparison. Results All femoral artery anastomoses in the experimental and control arm had good, pulsatile blood flow by microscopic evaluation. No thrombosed vessels were visualized, and Doppler signals remained strong at all vessel anastomoses. Histological analysis of the vessels revealed a trend toward increased inflammatory infiltrate in the walls of the vessels treated with cisplatin. We did not appreciate a functional decrease in lumen size. Conclusions Selective catheterization intra-arterial cisplatin chemotherapy does not affect the patency of vessels following a microvascular anastomosis in the rat model. The trend toward increased inflammatory response in the vessel walls may suggest the need for closer monitoring in patients treated with intra-arterial chemotherapy. [source]

Abnormal peripheral vascular response to occlusion provocation in normal tension glaucoma patients

ACTA OPHTHALMOLOGICA, Issue 2007
J WIERZBOWSKA
Purpose: To assess peripheral vascular reactive hyperemia in response to occlusion provocation test, using two-channels laser Doppler probe in patients with normal tension glaucoma (NTG) and normal subjects. Methods: 15 patients with NTG (12 women and 4 men), mean aged 58,9 and 15 control subjects (13 women and 2 men), mean aged 60,6 were subjected to an occlusion test. The experiment comprised following steps: 1/ a 5-minute baseline-period 2/ a 2-minute occlusion of the left hand using a 15 cm wide cuff located directly over the elbow (the pressure in the cuff was 50 mmHg higher than the systolic pressure measured on the arm 3/ a 15- minute final recovery period after occlusion. Finger hyperemia was assessed by two-channels laser-Doppler flowmeter MBF-3d, Moor Instruments, Ltd., continuously during the experiment. For measurements of hyperemia two surface probes were attached to the pulp of the second finger (mean probe) and third finger (basic probe) of the left hand. The following hyperemia parameters were measured: RF (rest flow), BZ (biological zero), TM (time to peak flow), TH (half-time of hyperemia), MAX (maximum of hyperemia) and hyperemia amplitude (MAX-RF)/RF 100% was calculated. Kruskal-Wallis test analysis was used to test the differences between the group of patients and normal subjects for TM1,MXF1 (basic probe) and TM2, MXF2 (mean probe) parameters. Results: In NTG patients, TM1 was significantly higher comparing with healthy subjects whereas MAX was significantly lower as compared to the control group. Conclusions: Occlusion provocation test elicits a different systemic hyperemia response in patients with NTG compared with healthy subjects. [source]

Exercise prevents age-related decline in nitric-oxide-mediated vasodilator function in cutaneous microvessels

THE JOURNAL OF PHYSIOLOGY, Issue 14 2008
Mark A. Black
Ageing is associated with impaired endothelium-derived nitric oxide (NO) function in human microvessels. We investigated the impact of cardiorespiratory fitness and exercise training on physiological and pharmacological NO-mediated microvascular responses in older subjects. NO-mediated vasodilatation was examined in young, older sedentary and older fit subjects who had two microdialysis fibres embedded into the skin on the ventral aspect of the forearm and laser Doppler probes placed over these sites. Both sites were then heated to 42°C, with Ringer solution infused in one probe and N -nitro- l -arginine methyl ester (l -NAME) through the second. In another study, three doses of ACh were infused in the presence or absence of l -NAME in similar subjects. The older sedentary subjects then undertook exercise training, with repeat studies at 12 and 24 weeks. The NO component of the heat-induced rise in cutaneous vascular conductance (CVC) was diminished in the older sedentary subjects after 30 min of prolonged heating at 42°C (26.9 ± 3.9%CVCmax), compared to older fit (46.2 ± 7.0%CVCmax, P < 0.05) and young subjects (41.2 ± 5.2%CVCmax, P < 0.05), whereas exercise training in the older sedentary group enhanced NO-vasodilator function in response to incremental heating (P < 0.05). Similarly, the NO contribution to ACh responses was impaired in the older sedentary versus older fit subjects (low dose 3.2 ± 1.3 versus 6.6 ± 1.3%CVCmax; mid dose 11.4 ± 2.4 versus 21.6 ± 4.5%CVCmax; high dose 35.2 ± 6.0 versus 52.6 ± 7.9%CVCmax, P < 0.05) and training reversed this (12 weeks: 13.7 ± 3.6, 28.9 ± 5.3, 56.1 ± 3.9%CVCmax, P < 0.05). These findings indicate that maintaining a high level of fitness, or undertaking exercise training, prevents age-related decline in indices of physiological and pharmacological microvascular NO-mediated vasodilator function. Since higher levels of NO confer anti-atherogenic benefit, this study has potential implications for the prevention of microvascular dysfunction in humans. [source]