Week 4 - Tri 2 Flashcards
(14 cards)
What can cause the cervix to look abnormally short?
- overly distended bladder
- uterine contraction
How do you improve ergonomics?
- elevate chair
- lower the table
- tilt the monitor to your eyes
- ask the patient to move closer to you and the machine
- turn on patients own monitor
- respond to any aches or pains throughout study
Why are system presets and system optimization important
Because of maternal habitus and fetal lie significantly impact the ultrasound appearances and presets may need to be adjusted to accommodate
What settings can be changed to importance scanning visualization
- transducer (always begin with highest frequency curvi-linear)
- TGC, focal zone, overall gain
- dynamic range
- harmonics
- compound
- persistence (increase or decrease)
What can you do to reduce MI and TI?
- decrease power output
- limit exam to 1 hr
- avoid spectral colour and power Doppler
- use m mode to measure heart
- decrease excess depth as increased depth uses higher output
- decreased spectral Doppler power when obtaining traces
- use write zoom
- change colour box size (smaller)
- decrease PRF to only what’s required
What is used to manage a short cervix?
Progesterone and cervical cerclage (cervical stitch)
When is a patient at risk of premature delivery?
When there is endocervical dilatation and shortening of the cervix
List 5 major and minor risk factors for spontaneous preterm labor.
Major
1. Multiple gestation
2. Previous preterm delivery
3. Abdominal surgery during pregnancy
4. Hydramnios (excess fluid)
5. Uterine anomaly (unicornate)
Minor
1. Febrile illness during pregnancy
2. Bleeding after 12 weeks
3. Hx of pyelonephritis
4. Cigarette smoking (>10 per day)
5. One second trimester abortion
What is the classic presentation of cervical incompetence?
Painless dilatation followed by fetal expulsion that occurs in second trimester.
List 5 risk factors for cervical incompetence
- Major uterine anomalies (unicornis, bicornis, didelphys)
- Hx of cervical trauma (cone biopsy and laceration)
- Recurrent spontaneous and therapeutic abortions
- Preterm birth before 32 weeks
- In utero exposure to diethylstilbestrol
What’s the primary role of cervical sonography?
To diagnose cervical incompetence in a group of patients at risk but who do not have a classic history
What are the ways to view uterine cervix by US
TV, TA, TL
Explain how an overly distended bladder and uterine contraction can cause abnormal cervix
Distended bladder: can mask true cervical dilatation as the bladder compresses the cervix and obliterates the fluid within the endocervical canal
Contraction: false hourglass membranes is the appearance of cervical dilation caused by contractions of the lower uterine segments, a low lying fibroid or a large about of fluid in the vagina. These can be excluded by recognition of a closer internal OS.
What are the early signs of cervical incompetence in US?
- Shortened cervical length <2.5mm
- Funnel shaped cervix (internal part of cervix starts to open creating a funnel shape)
- Building fetal membranes (amniotic sac bulges through cervix into vagina - late stage)
- Dynamic cervix (cx starts to changes in length or shape during scan)
- Open internal OS
