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Umbilical artery doppler sonography for fetal surveillance: Principles and practice
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Dev Maulik, David Mundy, Timothy Bennett
In contrast to high-risk pregnancies, trials of UA Doppler as a screening test in low-risk pregnancies did not show any improvement in pregnancy outcome. For example, a multi-center French randomized trial involving 4187 low-risk pregnant mothers failed to observe any improvements in the outcome with routine UA Doppler sonography between 28 and 34 weeks of gestation (69). Goffinet and coworkers conducted a systematic review of four trials selected out of seven studies and found no impact of UA Doppler on perinatal mortality in 11,451 low-risk pregnant mothers (odds ratio 0.51, 95% CI 0.20–1.29) (70). The Cochrane review of the topic in 2007 that included five trials with a total population of 14,338 women found no benefits of routine Doppler sonography in pregnancy (71). Moreover, the possibility of adverse outcome as suggested in two studies needs further investigation. In conclusion, routine Doppler ultrasound in low-risk pregnancies should be discouraged in clinical practice unless it is conducted under an approved experimental protocol.
Ultrasound Physics
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
When ultrasound imaging of vessels and Doppler measurements are combined, this provides a powerful tool for displaying blood flow velocity profiles from specific vessels or regions of interest. Doppler ultrasound is commonly used to image the heart (Echocardiography) and vasculature. (Table 3.4). By manually adjusting a cursor to coincide with the direction of flow, scanners combining pulse-wave (PW) Doppler with B-mode imaging can accurately estimate blood flow velocities in the heart and major vessels after adjustment for Doppler angle. B-mode and Colour Doppler are often combined with spectral (PW) Doppler to estimate flow in major vessels. Manufacturers have also started offering vector Doppler imaging where the magnitude and direction of flow is indicated by coloured arrows. More recently, with the advent of “ultrafast” Doppler and “microvascular imaging”, perfusion and microvascular flow measurements have also become possible.
Vascular access
Published in Mark Davenport, James D. Geiger, Nigel J. Hall, Steven S. Rothenberg, Operative Pediatric Surgery, 2020
Marcus D. Jarboe, Ronald B. Hirschl
The radial artery is the preferred site for both percutaneous and cut-down cannulation (Figure 1.8a). The presence of adequate collateral flow must first be checked by the Allen test; both arteries are occluded at the wrist and after releasing the ulnar artery alone, the hand should flush pink (most hands have an ulnar dominant palmar arch). Alternatively, a Doppler ultrasound study may be performed. A small roll is placed under the supinated, extended wrist and the palm is taped to a padded surface, keeping the fingers exposed in order to assess the distal circulation. The skin is cleaned with antiseptic and a small quantity of local anesthetic is injected subcutaneously over the radial artery just proximal to the transverse crease at the wrist. The technique of using ultrasound is described in the section “Ultrasound—Transverse orientation.” If ultrasound or ultrasound skills are not available, percutaneous insertion by palpation can be performed. The artery position is verified by palpation. Two techniques are used. In the first, the needle and Teflon cannula are advanced at about 30 degrees to the skin until a flashback of blood is seen (Figure 1.8b). In the transfixion method, the artery is transfixed by the needle and cannula. The needle is then removed and the cannula is gently withdrawn until arterial blood appears when it is advanced up the artery lumen.
Management of a patient with unintended intravenous dihydroergotamine infusion extravasation causing brachial artery vasospasm
Published in Baylor University Medical Center Proceedings, 2023
Vascular surgery was consulted and the patient was transferred to the surgical intensive care unit for hourly neurovascular exams, heparin infusion, and attempted vasodilation with intravenous nitroprusside infusion and subcutaneous phentolamine injections. Despite these efforts, the patient’s symptoms did not improve. Thus, she was taken to the operating room for arteriogram, balloon angioplasty, and catheter-directed intra-arterial injection of nitroglycerin within the right brachial artery (Figure 2). A right radial artery approach was utilized. Postprocedure imaging in the operating room revealed improved blood flow to the right hand, and the patient reported improved pain and resolving numbness. Follow-up Doppler ultrasound revealed improved blood flow in the right proximal brachial artery from preoperative peak velocity of 293.8 cm/sec to 160.2 cm/sec postoperatively. One-month follow-up arterial Doppler ultrasound demonstrated further improvement of flow velocity of the same region to 95 cm/sec.
Long-term outcomes of symptomatic and asymptomatic patients undergoing carotid endarterectomy in an average-volume community hospital
Published in Acta Chirurgica Belgica, 2021
José M. Alvarez Gallesio, Patricio Gimenez Ruiz, Michel David, Martin Devoto, Alejandro Caride, Raúl A. Borracci
In-hospital all-cause mortality and major operative complications were assessed, including transient or permanent stroke, acute coronary syndrome, carotid restenosis or occlusion, and wound complications. Outcomes for symptomatic and asymptomatic patients were analyzed separately. During follow-up, endpoints were all-cause long-term mortality, ipsilateral stroke, carotid restenosis or acute coronary syndrome. Follow-up was directly conducted by surgeons, cardiologists, or neurologists. The first appointment in the office was made within 2 weeks after surgery, then at 3, 6, and 12 months, and finally once a year. Patients with less than 6-month follow-up were excluded. Doppler ultrasound was indicated 3 months after surgery and once a year, unless required due to a particular clinical finding. Any doubt on ultrasound findings was assessed with MRI or CT angiography.
Systemic immune-inflammation index is associated with increased carotid intima-media thickness in hypertensive patients
Published in Clinical and Experimental Hypertension, 2021
Ömer Faruk Çırakoğlu, Ahmet Seyda Yılmaz
The patients were scheduled for an arterial doppler ultrasound examination. The left and right common carotid arteries were examined by the same experienced sonographer who was unaware of patients’ clinical data. Sonographic examinations of the left and right main carotid arteries were conducted with a high-resolution ultrasound system (Toshiba Aplio 300 Toshiba Co. Ltd., Tokyo, Japan). The linear transducer was used with a target frequency of 10.0 MHz (range 8.0–12.0 MHz) to obtain carotid IMT. Patients were examined in the supine position with the head tilted backward. Longitudinal images of the anterior and posterior walls were obtained. The region, one-centimeter proximal portion of the carotid bifurcation was identified, and high-resolution images of the far wall of the bilateral common carotid artery (CCA) were acquired according to recommendations of the American Society of Echocardiography Carotid Intima-Media Thickness Task Force (11). CIMT was defined as the measurement between the leading edge of the lumen-intima echo and the leading edge of the media-adventitia echo. Two best-quality images were selected for each CCA segment, and these measurements on both sides were averaged to acquire the mean CIMT. CIMT ≥0.9 mm was considered to represent subclinical atherosclerosis or asymptomatic organ damage (2).