Standardising echocardiography and images
1. Review of ECHO eligibility criteria - trial entry - rescue treatment 2. Assessments - personnel - timing 3. Technical aspects of ECHO examination
1. Trial entry What assessments need to be performed? Assessing eligibility for inclusion: Obtain high left parasternal ( ductal cut ) view Assess ductal patency and ductal flow characteristics Measure ductal dimension
What assessments need to be performed? (1) 2. Subsequent examinations - 3 weeks - Discharge ECHO - Rescue treatment In addition to (1) the following assessments should be performed: Assess presence of a hyperdynamic circulation Assess presence of ductal steal
ECHO criteria for Baby-OSCAR trial Trial entry 1. PDA dimension of 1.5 mm and 2. Unrestrictive pulsatile left to right flow in PDA Rescue treatment 1. Presence of a large PDA 2.0 mm and 2. Unrestrictive pulsatile left to right flow in PDA and 3. Presence of a hyperdynamic circulation or ductal steal
Who can perform ECHO assessments? Neonatologists or cardiologists (consultants/trainees) who have expertise in neonatal echocardiography and are able to visualise and assess the ductus arteriosus using conventional views Nominated echocardiographers should appear in Delegation Log
Cardiac structure At the first scan, it is desirable that the echocardiographer screens for normal cardiac anatomy. If any structural heart disease is suspected clinically or echocardiographically, appropriate action should follow according to local policy
WARNING You are entering an Evidence Free Zone
ECHO assessment Assessment of ductal patency and flow characteristics Assessment of ductal dimension Assessment of a hyperdynamic circulation Assessment of ductal steal
1. Assessment of ductal patency and flow characteristics
Right to left shunt > 30% of cardiac cycle should be considered abnormal
Bidirectional pattern Growing pattern
Closing pattern Pulsatile pattern
Pulsatility ratio = 3.13/2.03 = 1.54 Pulsatility ratio > 2 considered to represent pulsatile flow pattern Pulsatility ratio = 2.55/0.47 = 5.43
2. Assessment of ductal dimension Obtain high left parasternal ( ductal cut ) view. Optimise colour flow gain settings by: (1) adjusting colour gain scale to obtain optimal colour flow within the course of the ductus (2) adjusting colour gain to eliminate any peripheral colour interference by reducing gain until colour flow cannot be seen outside blood vessels Measure colour flow dimension at narrowest point by frame-to-frame analysis of the video loop selecting frames with the clearest discrete appearance of the ductus. Use 2D imaging to guide the point at which colour dimension should be measured. Calculate the mean of at least three measurements.
Pulmonary end of ductus
3. Assessment of a hyperdynamic circulation Measure left atrial: aortic root ratio using M-mode, ensuring the cursor is at right angles to the aorta and the posterior wall of the left atrium. Repeat (b) and calculate the mean of at least three measurements A LA/Ao ratio of > 2.0 is considered to represent significant left atrial dilatation secondary to volume overload of the left heart
4. Assessment of ductal steal Obtain view of descending aorta using a high parasternal or arch view Sample post-ductal aortic flow using pulse wave Doppler using angle-correction if necessary Record the presence of retrograde post-ductal aortic flow. Coeliac or superior mesenteric artery flows are acceptable alternatives
Retrograde diastolic flow is considered abnormal
ECHO assessment: summary Screening echo to detect structural heart disease, followed by: 1. Assessment of ductal patency and flow 2. Assessment of ductal dimension 3. Assessment of a hyperdynamic circulation 4. Assessment of ductal steal
ECHO criteria for Baby-OSCAR trial Trial entry 1. PDA dimension of 1.5 mm and 2. Unrestrictive pulsatile left to right flow in PDA Rescue treatment 1. Presence of a large PDA 2.0 mm and 2. Unrestrictive pulsatile left to right flow in PDA and 3. Presence of a hyperdynamic circulation or ductal steal
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