When ultrasound waves reflect off moving objects such as blood flow, the wave frequency is slightly altered which the Doppler picks up as signals, processes and amplifies so they are audible.Ī higher frequency probe (5 or 8MHz) will be suitable for listening to superficial objects such as blood vessels.
The term ‘Doppler effect’ dates back to Austrian physicist Christian Doppler (1803-1853) who found that the distance between waves, such as sound or light, changes as an observer of the waves and the source of the waves move relative to each other.ĭopplers detect reflections of small, high frequency sound waves (ultrasound) generated by microscopic vibrations of a ceramic crystal. The procedure should be carried out by appropriately trained practitioners who should endeavour to maintain their skills.¹⁰ The Scottish Intercollegiate Guideline Network (SIGN) (2010) guidelines stress the importance of calculating the ABPI (ankle brachial pressure index) in patients with chronic venous leg ulceration before treatment begins. The RCN recommends that a thorough clinical history and physical examination should precede patient assessment and investigations to identify any underlying cause and associated disease processes that may be contributing to the development of the ulcer (whether thought to be of venous or non-venous origin) and to aid diagnosis, referrals if necessary, and prognosis.² The two potential extremes are that the patient with arterial insufficiency does not receive the correct local management and suffers serious damage and the care of the patient with a chronicvenous leg ulcer is unnecessarily prolonged with the associated risks of extension of the ulcer and infection.
Assessing individuals with leg ulcerationĭoppler ultrasound assessment is a vital and indispensible element of the process of assessing patients with leg ulceration prior to planning care however, evidence shows that many patientassessments do not include Doppler assessment.⁶,⁷ Lack of knowledge, training, equipment, resources and confidence has been cited as reasons for this oversight.⁸ This situation in the past has led to ineffective care and inappropriate treatment.⁴,⁷,⁹
0 kommentar(er)
