Initial management of ruptured abdominal aortic aneurysm (AAA)

Ruptured AAA
The typical presentation of a ruptured AAA is a patient of over 60 years of age with a history of collapse associated with back, flank or abdominal pain and arriving with haemodynamic compromise. An ‘expansile mass’ representing the aneurysm may or may not be palpable.

Symptomatic AAA
There is a large cohort of patients in the Highlands with a known AAA due to our mature Screening Programme. These patients may present with abdominal symptoms but no collapse or haemodynamic compromise. Such a patient is considered to have a symptomatic AAA and will require less urgent attention. The final judgement should be made by the Vascular Consultant on call.

Referral Pathway
All patients accepted from the community with a suspected ruptured AAA should be directed to resuscitation room in the A&E department. Patients who are already in Raigmore Hospital should remain in their current location when the suspicion of a ruptured AAA is raised. They must be promptly treated and monitored by the parent team until seen by the Vascular team.

Vascular Surgical Input
All suspected cases of ruptured AAA must be referred immediately to the Vascular Consultant on call. This can be done via switchboard (“Can you page the Vascular Consultant on call please”) The Vascular Consultant on call will attend the patient where possible or delegate to the General Surgical Registrar on call or a Vascular Consultant colleague.

Initial Management prior to Vascular Assessment
All patients with suspected ruptured AAA should receive the following initial treatment prior to assessment by the Vascular team:

• High oxygen flow
• Good IV access but no fluid resuscitation (see notes on permissive hypotension)
•  Monitoring with pulse oximeter, ECG and non – invasive BP every 5 minutes
  
• Blood sent off for FBC, U&E’s, Coagulation, group & save

Vascular assessment
The Vascular team will assess the patient and take appropriate action

• Clinical diagnosis of ruptured AAA in a haemodynamically compromised patient: transfer to theatre without delay or arrange palliative care where indicated
• Suspected ruptured AAA but AAA not known and not palpable: arrange immediate ultrasound scan at the bedside or immediate CT scan via on call Consultant Radiologist depending on degree of haemodynamic compromise
• Suspected catastrophic event but possible alternative diagnosis: arrange immediate CT scan via on call Consultant Radiologist
• Symptomatic AAA or other condition which is not immediately threatening: arrange CT scan at an appropriate time via on call Consultant Radiologist

Initial Vascular Management
The Vascular team will take the following action as soon as a ruptured AAA is considered likely or is already confirmed:

• Activate major haemorrhage protocol
• Ask the team leader in the emergency theatre to set up for a ruptured AAA
• Inform the on call Consultant Anaesthetist if not involved already
• Seek communication with the patient’s relatives

Transfer to CT scanner
A patient who is being transferred to the CT scanner requires:

• Continue monitoring with pulse oximeter, ECG and non-invasive BP every 5 minutes
•  Patient needs to be accompanied by at least one Nurse and Doctor at all times
•  Resuscitation equipment available en route
•  Vascular Consultant will discuss the type of imaging with Radiology Consultant on call. The norm is a CT scan of abdomen and pelvis with IV contrast.

Transfer to Theatre
A patient with confirmed ruptured AAA who is being transferred to theatre requires:

• Continuous monitoring with pulse oximeter, ECG and non-invasive BP every 5 minutes
• Patient needs to be accompanied by at least one nurse and doctor at all times
• Resuscitation equipment available en route
• Vascular Consultant informs the Team Leader in the emergency theatre of expected time of arrival
• Consultant Anaesthetist arranges postoperative care facility, usually a bed in ICU

Set up in theatre
The setup in theatre relies on prompt and clear concise communication:

• The default theatre location is Th8. The Theatre Team Leader will arrange an alternative theatre if not available
• The patient should go straight into theatre bypassing the anaesthetic room
• Vascular Consultant, Anaesthetic Consultant and Theatre Team Leader will each arrange appropriate staff to come to theatre
• Theatre set up includes major vascular tray, aortic clamps, large Foley catheter for balloon occlusion of the aorta,  table mounted retractor system, two functioning suction machines
• On arrival in theatre the patient may need additional IV access and a urinary catheter
• There should be a mini pause checking patient identity, allergies, availability of blood and products.
• Induction of anaesthesia will start once the patient is fully prepped/drape. Both Scrub Nurse and Surgeon must confirm they are ready to go

Notes on permissive hypotension
Preoperative resuscitation of ruptured AAA patients with hypotension must be judicious. Aggressive volume resuscitation before aortic control is a predictor of increased postoperative mortality by overcoming the tamponade that stabilized the intial rupture. This can also cause hemodilution, coagulopathy, hypothermia, and acidosis, and further deterioration. Fluid resuscitation is minimized to maintain consciousness, to prevent ST depression, and usually to maintain a systolic pressures of 70 to 80mmHg.