Term 5 week 4 (w/c 4/2/13)
Let’s head back out of the comfort of the Theatre suite.
This week we are going to start in the X Ray suite. We have previously discussed the MRI scanner but this week it’s the Radiation side of the department.
What are the issues that need to be considered for anaesthesia in Radiology?
The case this week is in neuro radiology. A 54 year old lady has been admitted for embolisation of a Basilar tip Aneurysm. The aneurysm is unruptured.
What information would you like? Do you have a plan?
Some useful questions being asked by the team. It is often fascinating that the neuro juniors may fail to record blood pressure as part of their initial assessment! However, past medical history is unremarkable. Blood pressure is 136/74 mmHg. There is a post op level 2 bed.
Lets have a plan.
Embolisation is relatively unstimulating. Many different anaesthetic techniques have been used.
Do you have strong feelings about which airway device to use?
If so….. Which device AND Why?
The Expert Says
There are lots of reviews which illustrate the problems associated with anaesthesia outside of the theatre environment. The major one affecting radiology is that it is usually geographically remote from theatre and help is not easily available in the event of an emergency.
Elective embolisation of unruptured intracranial aneurysm is, however, not an uncomplicated procedure and brings with it a special set of risks. Giving a decent neuro anaesthetic is the primary goal with attention to detail over cardiovascular, ventilation and temperature control. It is always important to consider what can go wrong and either rupture of the vessel or occlusion of the vessels might prompt different radiological and surgical interventions just when you thought it was safe to send for the next case.
That leads us to the crux of this week’s case. The airway! The procedural need is for a completely still patient. Although various techniques such as neuroleptanaesthesia have been used in the past it is normal practice to use either TIVA or a vapour anaesthetic. Remifentanil makes the whole procedure very controllable and, along with the requirement for a still head, means there is a real need for controlled ventilation. Access to the head and airway is strictly limited during quite prolonged periods of darkness and faff. It now seems inevitable that intubation with an ETT is necessary. A south facing RAE is ideal. Well managed anaesthesia with intubation should be smooth and straightforward. However, it is not uncommon to use positive pressure ventilation and a Laryngeal Mask in well chosen patients with an low airway pressure, excellent LM fit, low BMI, asymptomatic for any GORD and good respiratory function is certainly an option. The trade off is intraoperative anaesthetist anxiety against undoubtedly smoother induction and emergence.
Clearly the longer the procedure, the less comfortable that trade off feels. That brings us right back to the first statement that radiology is remote and assistance slower to arrive. If in doubt, keep it simple and the use of an ETT keeps it as simple as possible!
Thanks to Ian G for that contribution.
See you next week.
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