Doppler Blood Flow Monitoring Research Articles

Multifunctional carbomer based ferulic acid hydrogel promotes wound healing in radiation-induced skin injury by inactivating NLRP3 inflammasome

BackgroundRadiation-induced skin injury is a significant adverse reaction to radiotherapy. However, there is a lack of effective prevention and treatment methods for this complication. Ferulic acid (FA) has been identified as an effective anti-radiation agent. Conventional administrations of FA limit the reaching of it on skin. We aimed to develop a novel FA hydrogel to facilitate the use of FA in radiation-induced skin injury.MethodsWe cross-linked carbomer 940, a commonly used adjuvant, with FA at concentrations of 5%, 10%, and 15%. Sweep source optical coherence tomography system, a novel skin structure evaluation method, was applied to investigate the influence of FA on radiation-induced skin injury. Calcein-AM/PI staining, CCK8 assay, hemolysis test and scratch test were performed to investigate the biocompatibility of FA hydrogel. The reducibility of DPPH and ABTS radicals by FA hydrogel was also performed. HE staining, Masson staining, laser Doppler blood flow monitor, and OCT imaging system are used to evaluate the degree of skin tissue damage. Potential differentially expressed genes were screened via transcriptome analysis.ResultsGood biocompatibility and in vitro antioxidant ability of the FA hydrogels were observed. 10% FA hydrogel presented a better mechanical stability than 5% and 15% FA hydrogel. All three concentrations of FA remarkably promoted the recovery of radiation-induced skin injury by reducing inflammation, oxidative conidiation, skin blood flow, and accelerating skin tissue reconstruction, collagen deposition. FA hydrogel greatly inhibiting the levels of NLRP3, caspase-1, IL-18, pro-IL-1β and IL-1β in vivo and vitro levels through restraining the activation of NLRP3 inflammasome. Transcriptome analysis indicated that FA might regulate wound healing via targeting immune response, inflammatory response, cell migration, angiogenesis, hypoxia response, and cell matrix adhesion.ConclusionsThese findings suggest that the novel FA hydrogel is a promising therapeutic method for the prevention and treatment of radiation-induced skin injury patients.Graphical

Nesfatin-1 regulates the HMGB1-TLR4-NF-κB signaling pathway to inhibit inflammation and its effects on the random skin flap survival in rats

ObjectiveRandom skin flaps are often placed by plastic surgeons to treat limb deformities and dysfunction. Nesfatin-1 (NES) is a peptide that exerts angiogenic, anti-inflammatory, and anti-oxidant effects. We assessed the impact of NES on flap survival and the underlying mechanism. MethodsWe modified the McFarlane random skin flap rat model. Thirty-six male Sprague-Dawley rats were randomly divided into a control group (corn oil solution with DMSO), low-dose group (NES-L at 10 µg/kg/day), and high-dose group (NES-H at 20 µg/kg/day). On day 7 after surgery, average flap survival areas were calculated. Laser Doppler blood flow monitoring and lead oxide/gelatin angiography were used to evaluate blood perfusion and neovascularization, respectively. Flap histopathological status was evaluated by hematoxylin and eosin (H&E) staining. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were determined. Immunohistochemical techniques were used to evaluate the expression of angiogenetic and inflammatory factors. ResultsIn the experimental groups, the mean skin flap survival areas and blood perfusion increased considerably. The SOD activities in the experimental groups increased and the MDA contents decreased. Immunohistochemically, VEGF expression was upregulated in the experimental groups and the expression levels of inflammatory factors decreased markedly. ConclusionNES inhibited ischemic skin flap necrosis, promoted angiogenesis, and reduced ischemia-reperfusion injury and inflammation. Inhibition of the inflammatory HMGB1-TLR4-NF-κB signal pathway, which reduced flap inflammation and oxidative stress, may explain the enhanced flap survival.

Knockdown of sortilin improves the neurological injury and regional cerebral blood flow in rats after subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a severe subtype of stroke. Sortilin protein is elevated in cerebrospinal fluid (CSF) of SAH patients. This study explored the mechanism of sortilin in SAH. SAH model was established by occipital cisternal blood injection. Neurological evaluation was performed on SAH rats using the Gracia scoring system and beam-balance tests. Regional cerebral blood flow (rCBF) and intracranial pressure (ICP) changes were measured using a laser Doppler blood flow monitor and an intraparenchymal Camino ICP probe. The correlation between rCBF changes and neurological deficit was analyzed using the Spearman method. Sortilin protein level in rat cerebral cortex and CSF was detected by Western blot. The Garcia score and beam-balance score of rats at 1, 12, 24, 48, and 72 h after SAH were lowered. Blood clots were observed on the ventral surface of the brain in SAH rats, around Willis ring, and ventral surface of brain stem, but no blood clots were found in the control group. At 1, 12, 24, 48, and 72 h after SAH in rats, the severity of SAH was aggravated, rCBF was decreased, and ICP was increased. The changes of rCBF in rat cerebral cortex at 1 and 72 h after SAH were correlated with the Garcia score. Sortilin was highly expressed in the cerebral cortex and CSF of SAH rats. Knockdown of sortilin improved the neurological injury and rCBF in rats. Sortilin was highly expressed in the cerebral cortex and CSF of SAH rats. Sortilin silencing improved neurological injury and CBF in rats.

Microembolic Signals in Arteries of the Base of the Brain after Ischemic Stroke.

Embolic strokes make up a significant proportion of acute cerebrovascular accidents. Doppler blood flow monitoring with microembolodetection allows suggesting the embolic nature of cerebral infarction. The aim of this study was to identify factors associated with the presence of microembolic signals in patients with ischemic stroke. The study included 515 patients, microembolic signals were detected in 48 (9.3%) of them. According to multispiral CT angiography, significant differences in patients with and without microembolic signals were found for wall thickness of both common carotid arteries and for left internal carotid artery (p<0.05). Factor analysis revealed a variable that reflects the severity of left carotid arteries atherosclerosis, which was a significant predictor of registration of the microembolic signals (p=0.016).

Laser Doppler for Accurate Diagnosis of Oehler’s Type III Dens Invaginatus: A Case Report

In vital pulp therapy, pulp testing aids in the differential diagnosis and influences the treatment plan. Different from previous doppler flowmetry studies that only recorded waves and data, we report the first time, the use of a laser doppler blood flow monitor and imager with a colored image to present pulp vitality information in the dental field. We report here a case of Oehlers type IIIa dens invaginatus of the right upper lateral incisor in a 31-year-old girl, with the opening of the invagination near CDJ and a peri-invagination lesion sized 8 × 9 mm2. Cone beam computed tomography was used to verify specific spatial and stereoscopic data. After removing the source of infection, mineral trioxide aggregate was selected to fill the invagination. Laser doppler was scheduled for further assessment. After three years of regular follow-up, the patient’s clinical condition improved, the peri-invagination lesion healed, and the laser doppler and electric pulp test both showed a positive reaction. Laser doppler has successfully improved the diagnostic accuracy Thus, unnecessary interventions can be avoided while reducing the treatment time by preserving the vitality. However, further work is needed to resolve the limitations of laser doppler.

Laser Doppler: A Tool for Measuring Pancreatic Islet Microvascular Vasomotion &lt;em&gt;In Vivo&lt;/em&gt;

As a functional status of microcirculation, microvascular vasomotion is important for the delivery of oxygen and nutrients and the removal of carbon dioxide and waste products. The impairment of microvascular vasomotion might be a crucial step in the development of microcirculation-related diseases. In addition, the highly vascularized pancreatic islet is adapted to support endocrine function. In this respect, it seems possible to infer that the functional status of pancreatic islet microvascular vasomotion might affect pancreatic islet function. Analyzing the pathological changes of the functional status of pancreatic islet microvascular vasomotion may be a feasible strategy to determine contributions that pancreatic islet microcirculation makes to related diseases, such as diabetes mellitus, pancreatitis, etc. Therefore, this protocol describes using a laser Doppler blood flow monitor to determine the functional status of pancreatic islet microvascular vasomotion, and to establish parameters (including average blood perfusion, amplitude, frequency, and relative velocity of pancreatic islet microvascular vasomotion) for evaluation of the microcirculatory functional status. In a streptozotocin-induced diabetic mouse model, we observed an impaired functional status of pancreatic islet microvascular vasomotion. In conclusion, this approach for assessing pancreatic islet microvascular vasomotion in vivo may reveal mechanisms relating to pancreatic islet diseases.

Laser Doppler: A Tool for Measuring Pancreatic Islet Microvascular Vasomotion In Vivo.

As a functional status of microcirculation, microvascular vasomotion is important for the delivery of oxygen and nutrients and the removal of carbon dioxide and waste products. The impairment of microvascular vasomotion might be a crucial step in the development of microcirculation-related diseases. In addition, the highly vascularized pancreatic islet is adapted to support endocrine function. In this respect, it seems possible to infer that the functional status of pancreatic islet microvascular vasomotion might affect pancreatic islet function. Analyzing the pathological changes of the functional status of pancreatic islet microvascular vasomotion may be a feasible strategy to determine contributions that pancreatic islet microcirculation makes to related diseases, such as diabetes mellitus, pancreatitis, etc. Therefore, this protocol describes using a laser Doppler blood flow monitor to determine the functional status of pancreatic islet microvascular vasomotion, and to establish parameters (including average blood perfusion, amplitude, frequency, and relative velocity of pancreatic islet microvascular vasomotion) for evaluation of the microcirculatory functional status. In a streptozotocin-induced diabetic mouse model, we observed an impaired functional status of pancreatic islet microvascular vasomotion. In conclusion, this approach for assessing pancreatic islet microvascular vasomotion in vivo may reveal mechanisms relating to pancreatic islet diseases.

Natural history of definitive diverticular hemorrhage based on stigmata of recent hemorrhage and colonoscopic Doppler blood flow monitoring for risk stratification and definitive hemostasis

Few prospective reports describe the short-term natural history of colon diverticular hemorrhage based on stigmata of recent hemorrhage, and none include blood flow detection for risk stratification or as a guide to definitive hemostasis. Our purposes were to report the 30-day natural history of definitive diverticular hemorrhage based on stigmata and to describe Doppler probe blood flow detection as a guide to definitive hemostasis. Different cohorts of patients with severe diverticular bleeding and stigmata on urgent colonoscopy are reported. For 30-day natural history, patients were treated medically. If severe rebleeding occurred, they had surgical or angiographic treatment. We report natural history with major stigmata (active bleeding, visible vessel, or adherent clot) and no stigmata or flat spots after clots were washed away. We also report Doppler probe detection of arterial blood flow underneath stigmata before and after hemostasis in a recent cohort. For natural history, patients with major stigmata treated medically had 65.8% (25/38) rebleeding rates, and 44.7% (17/38) had intervention for hemostasis. Patients with spots or clean bases had no rebleeding. A Doppler probe detected arterial blood flow in 92% of major stigmata--none after hemostasis--and there was no rebleeding. (1) Patients with major stigmata treated medically had high rates of rebleeding and intervention for hemostasis. (2) Patients with clean diverticula or only flat spots had no rebleeding. (3) High rates of arterial blood flow were detected under major stigmata with a Doppler probe, but with obliteration by hemostasis no rebleeding occurred.

Mo1034 Natural History of Definitive Diverticular Hemorrhage Based Upon Stigmata of Recent Hemorrhage and Doppler Blood Flow Monitoring

Mo1034 Natural History of Definitive Diverticular Hemorrhage Based Upon Stigmata of Recent Hemorrhage and Doppler Blood Flow Monitoring

2 Hz Electro-Acupuncture at Yinlingquan (SP9) and Ququan (LR8) Acupoints Induces Changes in Blood Flow in the Liver and Spleen

According to the principles of traditional Chinese medicine, channels and collaterals within the body provide pathways through which qi and blood travel, and each channel or collateral is linked with a specific organ. The Yinlingquan (spleen 9, SP9) and Ququan (liver 8, LR8) acupoints represent the sea points of the spleen and liver meridians, respectively, from which qi and blood flow into their specific visceral organs. The purpose of this study was to investigate the changes in blood flow/perfusion in the liver and spleen resulting from the application of 2 Hz electro-acupuncture (EA) to the Yinlingquan (SP9) or Ququan (LR8) acupoints. A total of 18 Spragrue-Dawley rats were randomly divided into three groups of six rats each as follows: sham group receiving sham EA; Yinlingquan (SP9) group receiving 2 Hz EA, applied at bilateral Yinlingquan (SP9) acupoints; and Ququan (LR8) groups receiving 2 Hz EA, applied at bilateral Ququan (LR8) acupoints. The mean blood flow/perfusion of the spleen and liver was recorded using a laser Doppler blood flow monitor prior to EA (representing the baseline), during EA, and post-EA. Each measurement period lasted ten minutes. Nitric oxide levels were also measured from the right femoral arterial blood, following the conclusion of each series of blood flow/perfusion recordings. The results indicate that the sham EA did not increase the mean blood flow/perfusion in the liver or spleen; 2 Hz EA at bilateral Yinlingquan (SP9) acupoints increased the mean blood flow/perfusion in the spleen, but not in the liver. In contrast, 2 Hz EA at bilateral Ququan (LR8) acupoints increased the mean blood flow/perfusion in the liver, but not in the spleen. Nitric oxide levels showed no significant difference between any of the groups at any stage of the measurements. According to the results, we conclude that EA at the Yinlingquan (SP9) and Ququan (LR8) acupoints can increase the blood flow in the spleen and liver, respectively.

An Implantable 20-MHz Ultrasonic Doppler Probe for the Postoperative Monitoring of the Buried Free Tissue Transfer: Report of A Case

Reconstructive microsurgeon is constantly striving to improve the success and salvage rates of free tissue transfer. Conventional free flap monitoring techniques are reliable for non-buried flaps. Buried flap monitoring is still a dilemma. In 1988, Swartz et al. did the first large-scale study of direct monitoring of microvascular anastomoses with the implantable 20-MHz ultrasonic Doppler probe. We present a case using the Cook-Swartz Doppler blood flow monitoring system for the postoperative monitoring of the buried free forearm flap in pharyngoesophageal reconstruction. It is a simple and reliable method of monitoring microvascular anastomoses without need for intensive care or monitoring units. The venous probe provides a greater degree of sensitivity, particularly to venous occlusion, compared with the arterial probe and has resulted in an increased success and salvage rate. We believed our initial case experience with this device supports the use of Cook-Swartz Doppler blood flow monitoring system as a promising technique for monitoring buried flaps and an adjunct to traditional clinical observation.

Integrated Optoelectronic Probe Including a Vertical Cavity Surface Emitting Laser for Laser Doppler Perfusion Monitoring

An integrated optoelectronic probe with small dimensions, for direct-contact laser Doppler blood flow monitoring has been realized. A vertical cavity surface emitting laser (VCSEL), and a chip with photodetectors and all necessary electronics are integrated in a miniature probe head connected to a laptop computer. The computer sound processor is utilized for acquisition and digital signal processing of the incoming Doppler signal. In this paper, the design of the laser Doppler perfusion monitor is described and its performance is evaluated. We demonstrate our perfusion monitor to be less sensitive to subject motion than a commercial fiber-optic device. For medium and high perfusion levels, the performance of our integrated probe is comparable to the fiberoptic flowmeter containing a normal edge-emitting laser diode. For very low perfusion levels, the signal-to-noise ratio of the fiber-optic device is higher. This difference can mainly be attributed to the shorter coherence length of the VCSEL compared with the edge-emitting laser diode.

The temporal effect of a high velocity thrust technique to the lumbar spine on cutaneous blood flow in the lower limb, comparing smokers and non-smokers

Background The lumbar high velocity low amplitude thrust technique (HVLAT) is a frequently used technique for the relief of spinal restriction and local somatic dysfunction. While this has generally been in order to achieve a local somatic correction and it is known to evoke a visceral response, 1,3 and a short term vascular response, 4 little has been published about the long term distal autonomic consequences. Smoking has a detrimental effect on the condition of blood vessels and the autonomic nervous system. 2,5 This experiment investigates the effect a lumbar HVLAT has on vascular perfusion in the lower limb over the period of an hour, and compares the effect of a lumbar HVLAT on non-smokers and smokers. Methods Thirty-six subjects received a unilateral HVLAT thrust at the lumbo-sacral junction. Twenty-six participated in the study, 15 non-smokers and 11 smokers. Five control subjects received no intervention. A laser Doppler Blood flow monitor measured subcutaneous blood flow in the dorsum of the foot in the L5 dermatome for a total of 60min. For statistical analysis the blood flow units were calculated as percentages with the baseline 5min reading being taken as 100% and subsequent 5min intervals being positive or negative. Results Following an HVT to the lumbo-sacral junction there was a significant difference ( P =0.02) in the 5min post-HVLAT period in the ipsilateral foot comparing smokers and non-smokers. There was no significant ( P >0.05) change in blood flow on the ipsilateral side of non-smokers. On the contralateral side there was a significant ( P =0.01) difference at 30min post-HVLAT and a significant difference ( P =0.006) at 55min post-HVLAT. In smokers there was a significant decrease ( P =0.02) in blood flow on the ipsilateral side in the 5min post-HVLAT period, which was also significant ( P =0.02) at 30min post-HVLAT but not at 55min. There was no significant change on the contralateral side of smokers. Conclusion This study indicates a difference in smoker and non-smoker response to the HVLAT. The author proposes that this is due to facilitation of the sympathetic nervous system in smokers causing a hyper-reactive predisposition.

Laser Doppler imaging: a developing technique for application in the rheumatic diseases.

Microcirculatory abnormalities contribute to the pathogenesis and pathophysiology of many of the rheumatic diseases. This is best recognized in systemic sclerosis (SSc), in which structural microvessel disease can be well demonstrated using the technique of capillary microscopy [1], and more recently by video and digital capillaroscopy [2, 3]. However, in many other conditions the microvasculature is more subtly involved. By the ‘microvasculature’ we mean the arterioles, the capillaries and the venules. Any inflammatory state is associated with profound microvascular perturbation. For example, in rheumatoid arthritis the synovial microvasculature undergoes major change with formation of new blood vessels (angiogenesis) in the hypertrophied synovium and with lymphocyte trafficking through high endothelial venules. These high endothelial venules are lined by specialized endothelial cells whose formation has been induced during the inflammatory process. [4]. In the study of disease, we must be concerned not only with understanding basic pathophysiology but also with the measurement of disease progression. If we cannot measure the disease, then we cannot assess its progression or responsiveness to treatment. In addition, the ability to measure disease processes can give us indirect insights into pathophysiology by allowing us to assess response to therapeutic interventions which are known to have specific mechanisms of action. Can we measure microvascular disease/involvement by disease, and apply this to the study of rheumatological disorders? As already mentioned, we can examine nailfold capillary structure in certain connective tissue diseases, such as SSc and dermatomyositis, using nailfold microscopy and video capillaroscopy, and one aspect of capillary function (permeability) can be examined by fluoroscopy [5, 6], which is, however, invasive in that it requires an intravenous dye injection. In this review we shall discuss the relatively new technique of laser Doppler imaging (otherwise termed ‘scanning laser Doppler’), which gives a direct measure of microcirculatory flow. We believe laser Doppler imaging affords significant potential in the study of microcirculatory involvement of the rheumatic diseases and it is non-invasive. Background to laser Doppler blood flow monitoring The observed wavelength of electromagnetic radiation is affected by relative motion between the source and observer. This phenomenon (also applicable to sound waves, as in the technique of Doppler ultrasound) is known as the Doppler effect. When low-level laser light, of a few milliwatts, is directed onto the skin’s surface a fraction of the light penetrates the skin and interacts with both static tissue and moving cells (primarily red blood cells). The penetration depth of light is dependent upon the tissue morphology, absorption and the wavelength used [7, 8]. The light that is reflected or randomly scattered from the static tissue remains unchanged in wavelength. In contrast the light that is scattered from the moving blood cells undergoes a small change in wavelength, proportional to the speed of the erythrocytes, due to the

Effect of wavelength and bandwidth on the clinical reliability of laser Doppler recordings.

The aim of this study was to investigate the effect of wavelength and bandwidth on laser Doppler flowmeter signals from vital and root-filled teeth, and to establish their sensitivity and specificity. Twenty human subjects were recruited, each with a vital tooth and the contralateral tooth root filled but not restored apart from the palatal access cavity. Readings were taken from these teeth for 3 min at 20 Hz for each of 3.1 kHz, 14.9 kHz and 22.1 kHz bandwidths using a modified laser Doppler blood flow monitor which permitted simultaneous recording using 810 nm and 633 nm light sources with a probe of four optical fibres with 0.25 mm separation. Ten traces from each combination of variables was examined by 10 trained observers who indicated if the traces came from vital or root-filled teeth judged by the amplitude and regularity of pulsatility of the trace. From the accuracy of their replies, sensitivity and specificity were calculated. Median flux values were higher for vital teeth than for root-filled teeth and for the 810 nm wavelength than for the 633 nm wavelength. Flux values increased with wider bandwidth using the 810 nm light source. With the 633 nm light source, the highest flux values were recorded using the 3.1 kHz bandwidth. Using the Mann-Whitney U test, there was a highly significant difference between readings from vital and root-filled teeth for the 3.1 kHz/810 nm wave length combination (p<0.003) and a significant difference for the 3.1 kHz/633 nm wavelength group (p<0.02). Comparison of other groups showed no significant difference (p>0.05). The 810 nm wavelength showed good sensitivity but poor specificity at 14.9 and 22.1 kHz bandwidths. The 633 nm wavelength showed good specificity, but poor sensitivity, at 14.9 and 22.1 kHz bandwidths. The 3.1 kHz bandwidth showed the best sensitivity and specificity for both wavelengths. Sensitivity and specificity were increased if the results of fast Fourier analysis were considered in addition to observations of flux values and pulsatility of traces. The 810 nm/3.1 kHz combination offered the greatest sensitivity and specificity as a test to distinguish between root-filled and vital teeth. This combination was best when the results of Fourier analysis were considered in addition to visual observations.

Effect of blood perfusion on the ablation of liver parenchyma with high-intensity focused ultrasound

This paper discusses the effect of blood perfusion on the ablation of rat liver tissue with high-intensity focused ultrasound (HIFU). For this study a practical method has been developed, in which the liver blood flow can be reduced by ligation of the hepatic artery and portal vein. During the treatment the rat liver was mobilized out of the abdomen and the blood flow was measured using both the radioactive microsphere method and a laser Doppler blood-flow monitor. The results show that the hepatic blood flow was about 23 ml/100 g min-1 via the hepatic artery and about 227 ml/100 g min-1 via the portal vein. The total liver blood flow was reduced by 98% when both the hepatic artery and portal vein were ligated. Comparative lesions were made on the same liver lobes of rats with both normal and reduced blood flow using a focused ultrasound beam of 1.7 MHz, 67-426 W cm-2 spatially averaged focal intensity ISAL and 2-20 s exposure duration. A marked difference has been found between the lesion dimensions obtained with normal blood flow and that with reduced blood flow. For exposures at 169 W cm-2 the lesion diameter with normal blood flow was reduced by 14% for 3 s exposure duration compared to that obtained with both hepatic artery and portal vein ligated, while the reduction was more than 20% for longer durations.

Hypertrophic Scar

Soft-tissue dermal loss does not regenerate; instead, it is replaced with scar. The extent of scarring is directly related to the severity of tissue loss (in terms of volume and depth). Commonly, an acute dermal loss will heal with excessive scar, hypertrophic scar. A hypertrophic scar is elevated but is contained within the boundaries of the initial injury. Hypertrophic scars have a reddish appearance, indicating an elevated local circulation. A laser Doppler blood flow monitor was employed to measure blood flow changes in healed wounds. It was speculated that local circulation in a developing hypertrophic scar would be elevated. Patients with recently healed wound sites were monitored and exhibited an average blood flow reading of 365 +/- 325 mV (n = 131). This average value, ranging from 98 to 1450 mV, was 18 times greater than the average reading from normal skin, which was 43 +/- 13 mV (n = 212). Blood flow declined to 32 +/- 21 mV (n = 7) at 16 to 18 weeks (74 percent of normal skin values) in healed wounds that developed normal scar. However, a closed wound that developed into a hypertrophic scar had a blood flow reading of 148 +/- 78 mV (n = 59) at 16 to 18 weeks. This value was three times greater than in normal skin and four times greater than in normal scar. At 38 to 50 weeks postinjury, hypertrophic scar remained elevated (102 +/- 34 mV; n = 10). Hypertrophic scars sustain an elevated blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of perioperative pulsed Doppler flowmetry in predicting postoperative local ischemic complications after ileocolic esophagoplasty

Regional ischemia may induce cervical anastomosis leakage or stenosis or graft necrosis after esophageal reconstruction by retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the relationship between immediate postoperative arterial blood supply to the graft, arterial patency monitored by angiography, and clinical outcome. Eight patients (mean age 30 +/- 4 years; standard deviation) were studied. Miniaturized Doppler implantable microprobes were sutured to the single artery supplying the graft and connected to an 8 MHz pulsed Doppler flowmeter. Systemic hemodynamic parameters and mesenteric hemodynamic data were collected 3 hours after the end of the surgical procedure. These data were compared with the angiogram of the right superior colic artery supplying the graft, systematically performed on the fifteenth postoperative day, and with the clinical course of follow-up for 3 months. Five patients (group 1) had excellent clinical and angiographic results. Mean mesenteric blood flow in these patients was 51 +/- 49 ml.min-1 (+/- standard deviation, ranging from 9 to 122). Three patients (group 2) had a poor clinical outcome. One had early complete graft necrosis and the two others had leakage of the cervical anastomosis with poor distal arterial vascularization of the graft on the angiogram. Mean mesenteric blood flow was nul in the first patient and, respectively, 24 and 28 ml.min-1 in the two others. Cardiac output and mean arterial pressure were in the same range for all patients. Phasic velocity shape analysis revealed that the three group 2 patients had an end-systolic or end-diastolic reverse flow pattern that was not observed in the five group 1 patients, which suggested a submaximal increase in downstream vascular resistance. This reverse flow pattern seems to be a good predictor of ischemia-related complications. We conclude that perioperative pulsed Doppler blood flow monitoring in an ileocolic graft may be useful for the diagnosis and prevention of ischemic complications.

Doppler ultrasound monitoring of systemic blood flow during CPR.

During cardiopulmonary resuscitation in 12 patients, Doppler ultrasound monitoring of radial arterial flow provided an audible, instantaneous flow sound to which the resuscitation team referred, along with the monitor electrocardiogram (EKG), in determining hemodynamic status. Incidental to the resuscitation effort, a separate analog flow signal and the monitor EKG were simultaneously recorded in eight patients. Doppler blood flow monitoring allowed evaluation of effectiveness of cardiac massage; immediate recognition of electromechanical dissociation; rapid determinations of blood pressure, often during profound hypotension, and estimates of changes in cardiac output. When the hemodynamic consequences were immediately obvious, both ineffective chest compression and pauses longer than five seconds during effective chest compression were not tolerated by those in attendance, for whom the Doppler flow signal often became the primary reference in determining the patient's cardiac status.