Abdominal Aortic Aneurysm repair pathway 



Open Aneurysm Repair


Pre-operative care

1.     See DOSA document

Post-operative care

  1. Patients will routinely be admitted to HDU and occasionally ICU.
  2. Read post-op care on operation note for any specific advice
  3. Monitor urine out-put to achieve > 30 mls per hour.
  4. Perform hourly foot observation for colour, palpable pulses or Doppler signals. Note the post operative note for pulse status.
  5. If a tense/tender calf is found post-operatively call the consultant vascular surgeon on call immediately. Check CK level.
  6. Monitor blood pressure to achieve 120-160 mmHg and heart rate <80 bpm.
  7. Monitor daily U&E for first 72 hours should creatinine rise for 2 consecutive days ensure consultant aware or if there is a rise > 40 points.
  8. Monitor Hb if <8 then transfuse 2 units. If patient has significant history of ischaemic heart disease then consider transfusion if <10.
  9. If blood pressure or urine output is low despite adequate fluid resuscitation assess abdomen for intra-abdominal compartment syndrome either clinically by examination and intra-vesical bladder pressure measurement. If evidence of organ failure and bladder pressure > 20mmg consider need for laparotomy call consultant vascular surgeon. If tense abdomen but no evidence of organ failure or increasing inotropes or lactate then monitor situation closely.
  10. During first 72 hours post-op or whilst in HDU monitor Lactate and ALT levels for rise that may indicate ischaemic bowel. If lactate increasing or significant diarrhoea consider performing Per Rectal examination for blood and seeking a general surgical opinion as appropriate or CT scan to assess for ischaemic bowel. Inform consultant vascular surgeon.
  11. Initially post –op patients can have 30 ml oral intake per hour. If after 12 hours this has been tolerate without vomiting or nausea then this can be slowly increased to free fluids. After 12 hours of free fluids then dietary intake of solid food can be slowly introduced. If the patient feels nauseated or vomits then they should return to 30 ml/hr orally. If vomiting continues then an NG tube should be inserted and left on free drainage and an abdominal radiograph obtained.
  12. On a daily basis assess lower limb perfusion for evidence of ischaemia.
      1. Are the feet warm with rapid capillary refill?
      2. Are movement and sensation intact?
      3. Are the calves soft and non-tender?
      4. Is there mottling in the feet or legs indicating hypo-perfusion?
      5. Trash/microembolisation presents as dusky toes or mottling over the sole or dorsum of the foot.
        • If there are concerns that there may be limb ischaemia then assess for the presence of pulses femoral to pedal and compare to those recorded pre-op and post-op. Some patients have peripheral vascular disease and therefore did not have pulses pre-op. Assess whether a posterior tibial or dorsalis pedis Doppler signal is present. If there is concern that there may be ischaemia do not waste time looking for a Doppler – discuss with consultant vascular surgeon. If the on call surgeon is not available call one of the other vascular surgeons they will be happy to help.

  13. After 24-48 hours on HDU patients can be transferred to the ward area if observations and blood tests are stable and no supportive care needed. At this point preparation for home can be continued with physiotherapy and mobilisation.
  14. If creatinine stable and urine output good then the urinary catheter can be removed. In men assess whether there is significant scrotal swelling which may make voiding difficult if so leave catheter until swelling resolves consider scrotal support.
  15. Patients should be prescribed post-operative an anti-platelet agent or re-start Warfarin and statin life long and this should be on the discharge script and summary.
  16. Peri-operatively patients should take all their usual analgesics except NSAIDS which should be omitted for 24hrs prior to surgery and for 72hrs postoperatively ie until renal function is stable/normal.
  17. Postoperatively, most patients will have an epidural in place. Presuming the epidural is providing good analgesia this should be continued for 48-72hrs. If sub-optimal block then pain team/first call anaesthetist (bleep 4600), depending on time of day, should be contacted for advice. If epidural is providing good analgesia but there is no discernible ‘block to cold’ then epidural should NOT be stopped but, as above pain team/first on call anaesthetist should be contacted for advice.
  18. Post-operatively, paracetamol 1g QDS (reduced if body weight <50kg) PO/IV 6hourly should be prescribed as should a weak opioid of the anaesthetists choosing. It should be clearly documented in the notes section of the prescription chart that this should NOT be given concurrently with epidural infusion (as this contains fentanyl) however should be prescribed so that it can be given once epidural is discontinued.
  19. All chronic pain medications that the patient was taking on admission should be administered postoperatively.
  20. Postoperatively epidural catheter most not be removed within 12hrs of prophylactic dose LMWH dose being administered (ESRA 2010).


Endovascular Repair


Pre-operative care

  1. The majority of patients will be admitted on the day of surgery (see DOSA document)
  2. Patients who are not appropriate for day of surgery admission will be admitted to the ward. Prescribe clexane 40 mg s.c. or daltaparin 5000 i.u. at 1800 hrs on the pre-operative evening.
  3. Perform a Group and Save and check the previous blood results


Post-operative care

  1. Patients may go to HDU or return to the ward and most will be performed under spinal anaesthesia (fenestrated stents are performed under general anaesthesia)
  2. Prescribe clexane 40 mg s.c or daltaparin 6 hrs post spinal removal.
  3. Patients can eat and drink when they have returned from the theatre.
  4. Monitor urine output this should be maintained above 30 ml/hr. If falls below this inform surgeon.
  5. Monitor blood pressure which should be maintained 120-160 mmHg (see anaesthetic sheet for specific guidance)
  6. Foot observations hourly. See operation sheet for specific guidance which regards to the presence of foot pulses.
  7. Document temperature, colour, capillary refill and movement of toes/ankle joints and any calf tenderness. Calf tenderness is to be reported to the surgeon immediately.
  8. Observe groin wounds half hourly for any signs of swelling or bleeding. Inform surgeon if any concerns.
  9. Ward Care
  10. The urinary catheter can be removed on the first morning post-op except with fenestrated EVAR which should be discussed with the consultant surgeon.
  11. Once the catheter is out and the groin wounds assessed for haematoma then the patient should be mobilised and physiotherapy assessment completed together with any OT as necessary.
  12. Patient should be planned for home on the second post-operative day.
  13. Patients should be discharged on aspirin and a statin. (Fenestrated and branch grafts should be discharged on Clopidogrel instead of aspirin)




Fenestrated Endovascular Repair (f-EVAR)


  1. Fenestrated EVAR (f-EVAR) require 6 hourly lactate levels whilst in HDU for 48 hours if lactate rises above normal limits then the consultant vascular surgeon must be informed immediately.
  2. If the patient complains of abdominal pain then the consultant vascular surgeon must be informed.
  3. On return to HDU an assessment of lower limb perfusion and function should be documented including pulses and muscle power. Any weakness post-op should be reported to the consultant vascular surgeon as consideration of a spinal drain may be needed.
  4. Urine output should be maintained >50 ml/hr whilst urinary catheter in place. If urine output drops to < 40 ml/hr for 2 successive hours then the consultant vascular surgeon should be informed.
  5. Creatinine should be checked daily for 72 hours postop. If creatinine rises the consultant vascular surgeon must be informed. If creatinine rises post-op daily creatinine levels should be performed until it reaches a plateau.
  6. If the creatinine does not rise then the urinary catheter can be removed after 48 hours.
  7. Fenestrated EVAR should be discharged with clopidogrel as a replacement for aspirin and this should be communicated to the GP on the discharge script and discharge letter


Emergency Endovascular repair of AAA (EmEVAR)


Emergency Endovascular repair of AAA (EmEVAR) is a new treatment option in leaking AAA shown to have a reduction in peri-operative morbidity and mortality in suitable patients. It avoids the systemic response associated with major haemorrhage and laparotomy however it is still associated with a SIRS response, coagulopathy and acute kidney injury.

The main principles of post procedure management are:

  • Maintaining cardio vascular stability
  • Correcting coagulopathy
  • Preventing AKI 
  • Minimising the SIRS reaction associated with reabsorption of the haematoma
  • Screen for and treat raised intra-abdominal pressure

Acute kidney injury is multi-factorial:
  • Compromised renal blood flow at time of leak
  • Low cardiac output state
  • Radiological contrast
  • Raised intra-abdominal pressure

Post-operative management in critical care

The procedure may be performed under local or general anaesthesia. On admission to critical care the patient may be sedated, intubated and ventilated or awake and spontaneously breathing but the principles of management are the same.

Post-operative instructions from the vascular and anaesthetic team will be written on the back of the anaesthetic chart. This will include: Target MAP, accepted maximum systolic BP, if the patient is suitable for TED stockings, IAP measurement at the end of the procedure and any other particular instructions for the individual patient.

On admission to critical care all patients require

    • Bloods: FBC, coagulation screen, U+E, LFT, Ca, Mg, Phosphate, Trop I, rpt x-match sample
    • CXR
    • ECG
    • Hourly measurement of intra-abdominal pressure
    • Assessment of limb perfusion
    • Prescription of post-op antibiotics, stress ulcer prophylaxis, analgesia and the patient’s regular medication if appropriate.

At 12 hours

    • FBC, Coag, U + E, Ca, Mg, Trop I
    • Rpt 12 lead ECG


Respiratory System

Principles of management:

Maintain adequate gas exchange: PaO2 > 10kPa, PaCO2 to achieve pH >7.20

If intubated:

      • Lung protective strategy for ventilation – 6-8ml/kg tidal volume, use PEEP, PAWP <30cm
      • Raised intra-abdominal pressure may compromise ventilation (see below), higher airway pressures may be required.

If spontaneously breathing:

      • Face mask oxygen titrated to PaO2
      • Non-invasive CPAP or BIPAP may be required, especially if abdominal distension
      • Sedation, intubation and ventilation according to standard criteria


Cardiovascular system

Principles of management           

              • Maintain cardiovascular stability
              • Avoid excessive hypertension
              • Rapidly correct coagulopathy
              • Monitor femoral puncture sites and peripheral limb perfusion
              •  Anti-coagulate when stable and low risk of bleeding

Target MAP as directed in post-op instruction

Ensure adequate filling – there may be ongoing bleeding especially if coagulopathy, use blood and blood products if indicated. Avoid starch solutions.

CVC line may need to be inserted to guide fluids and allow vasopressor administration

Use vasoconstrictors and inotropes according to patient condition (consider CO monitor)

Treatment of hypertension
            • Ensure adequate pain relief (not NSAIDs)
            • Commence patients usual anti-hypertensive medication (avoid ACE inhibitors)
            • Consider B-blockade if no contra-indications – Start with IV Metoprolol titrated to effect
            • Consider calcium antagonists – Amlodipine 5mg NG repeated if necessary
            • GTN infusion if NG route not available

Maintain Hb at 8-10g/dl

Monitor and correct coagulopathy (remember lab results have a time lag so treatment maybe required before results available if ongoing bleeding is apparent).

Correct coagulopathy if APTTR > 1.4, PTR > 1.4 using FFP or if bleeding apparent and borderline results

If signs of DIC use cryoprecipitate

Transfuse platelets if < 50

Discuss with haematologist if prolonged / profound coagulopathy

Monitor coagulation screen every 6 hours (DIC may be precipitated by resolving haematoma)

Actively warm the patient if temp<36۫

Measure and correct ionised calcium levels (available on ABG)

If patients were on warfarin they may have received Beri-plex. Consider further reversal of warfarin with vittamin k 10mg daily for 3 days depending on indication for warfarin (discuss with senior clinician and vascular team)

Monitor peripheral limb perfusion by palpating lower limb pulses or using Doppler USS 6hrly.

Monitor femoral puncture sites for signs of ongoing external or internal bleeding. Note perineal bruising and oedema may be extensive.

DVT Prophylaxis:

Ensure TED stockings are applied if deemed suitable by vascular team (see post-op instructions an anaesthetic chart)

Do not use sequential compression device (SCD) prophylaxis due to peripheral vascular disease

Do not start pharmacological DVT prophylaxis until at least 24hours post-procedure

           

GI system

Principles of management           

    •     Ensure adequate nutrition, ideally via enteral route
    •     Stress ulcer prophylaxis
    •     Monitor and treat intra-abdominal hypertension
    •     Monitor for signs of bowel ischaemia – abdo pain / rising lactate                                               

Nutrition:

Awake patients can eat and drink as tolerated

If sedated and intubated, insert NG tube and commence NG feed as per unit protocol

Stress ulcer prophylaxis:

Prescribe a  proton pump inhibitor if no contraindications, PO/NG if enteral nutrition.

IAP:      Measure Intra-Abdominal pressure (IAP) on admission (patient must be lying flat) and hourly for the first 4 hours. Normal IAP is < 5-7mmHg. IAP >20mmHg with associated organ failure is called intra-abdominal hypertension (IAH) and requires treatment – see guideline for IAP.

If IAP is <15mmHg:            Monitor IAP 4 hourly        

If IAP is >15mmHg:            Continue to monitor the IAP hourly

1.    Ensure adequate analgesia (and sedation if ventilated)

2.    Lie patient flat

3.    Maintain MAP 50-60mmHg above IAP – adequate filling, then vasopressors

4.    Insert NG tube and aspirate/free drainage of gastric contents (trade off between nutrition and IAH)

5.    Promote bowel emptying with pro-kinetics, aperients and enema’s

6.    Ensure bladder is empty with bladder scan

7.    If the patient is sedated and ventilated, consider the use of muscle relaxants

If signs of IAH i.e: sustained IAP >20mmHg with organ failure – oligo/anuria, high lactate, poor ventilation or poor tissue perfusion Discuss with senior surgeon the requirement for drainage of haematoma or laparostomy (opening the abdomen).


Renal system

Principles of management            

       Prevent further renal injury

       Recognise, monitor and treat AKI in usual way

       Avoid NSAID’s, ACE inhibitors, aminoglycosides and other nephrotoxins.

       Give post-procedure Contrast Induced Nephropathy prophylaxis:

o   Sodium bicarbonate 1.26% 1ml/kg/hr for 6 hours

o   N-Acetylcysteine 50mg/kg in 500ml saline over 4 hours

Monitor UO, if oliguric:   

  • Ensure adequate filling and MAP
  • Measure IAP and treat as above
    •               
    • Institute renal replacement therapy according to standard criteria

                                                  

    Pain control

    Principles of management

    The presence of a large haematoma may cause significant pain.

    Analgesics should be titrated according to pain score.

    PCA may be required. NSAID’s should be avoided.


    Antibiotic Prophylaxis

    Principles of management           

    24 hours prophylaxis required due to presence of foreign object (graft). 

    Patients will have received the first dose of antibiotics during the procedure.

           If normal renal function:

           If not allergic give Co-amoxyclav 1.2g, 8hrly for 2 further doses

           If penicillin allergic give single dose Teicoplanin 400mg 12 hours after first dose

           If impaired renal function:

           If not allergic give single dose Co-amoxyclav 1.2g 12 hours after first dose

           If penicillin allergic, ensure dose of Teicoplanin given during the procedure (If not administered then give single dose). No further dose required if given during the procedure.


    Temperature control

    Principles of management

    Being cold is uncomfortable for patients, increase’s oxygen demands and reduces blood coagulation

    Actively warm patients and fluids if temperature <36


    Neurological system

    Principles of management

    Endovascular repair of AAA may cause irreversible total or partial reduction in blood flow to the anterior spinal artery resulting in anterior spinal cord syndrome and loss of motor power in the affected myotomes.

    Assess patients’ lower limb power, if concerns inform vascular team. Commence management for acute spinal cord injury.

    Confusion or agitation may be the first sign of physiological deterioration and requires a thorough assessment of the patient and low threshold of suspicion that something is amiss.

          • Assess and treat Pain
          • Ensure adequate oxygenation / blood pressure / haemoglobin level
          • Ensure no urinary retention with bladder scan
          • Check lactate level (? Signs of bowel ischaemia)
          • Consider sedation +/- intubation and ventilation if required to ensure cardio-respiratory stability

                 

    If you have concerns about the patient or are unsure what to do then please ask a senior member othe Critical Care or Surgical team

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