• CEA should be performed as soon as possible after non disabling stroke or TIA

• The longer the time period before surgery, the greater the risk of stroke recurrence

• Perioperative blood pressure may be labile but should not preclude early surgical intervention

• Control of postoperative blood pressure should be managed using a stepwise approach under the direction of a consultant anaesthetist and in conjunction with the vascular surgeons

• Cerebral hyperperfusion syndrome resulting in haemorrhagic stroke is rare but catastrophic. The risk can persist into the late perioperative period (usually day 2-7 but occasionally up to 30 days)

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Abbreviations

To provide a protocol for use by medical and nursing staff at Frimley Health PACU to manage blood pressure in vascular patients in PACU and HDU/ITU who have had carotid endarterectomy.

Poorly controlled hypertension increases the risk of postoperative complications, including neck haematoma and hyperperfusion syndrome. The most catastrophic event that can occur secondary to hyper perfusion is intracerebral haemorrhage. This guideline aims to provide a framework for blood pressure control in the post operative period in an attempt to minimise the risk of this potentially fatal complication.

Carotid endarterectomy is performed on patients with evidence of atherosclerotic stenosis of the carotid artery. The decision to operate depends on the extent of disease (percentage stenosis of the carotid artery) and the presence of symptoms. When the diagnosis of disease follows a TIA or non-disabling stroke, then the operation should be performed as soon as possible, and NICE guidelines recommend within 14 days to reduce the incidence of stroke recurrence.

This procedure can be conducted under a general or regional anaesthetic technique. A large multicentre trial did not show any statistically significant differences in outcome between the two (GALA study). Neurological assessment (including cranial nerves) at the time of the preoperative anaesthetic assessment can be used as a baseline with which to compare perioperative and postoperative examinations. A change may indicate evidence of ischaemia or infarction.

The evidence that labile perioperative blood pressure leads to neurological and cardiovascular complications during CEA is inconsistent, however, the general consensus is that close monitoring and control of arterial pressure is desirable. This can be challenging to achieve in the acute period following a neurological event but the benefit of early surgery outweighs the potential risks of blood pressure instability.

Complications of CEA include

1. Thromboembolic stroke

2. Postoperative wound haematoma resulting in airway compromise

3. Myocardial ischaemia and infarction (due to underlying risk factors, IHD, heart failure, DM and COPD)

4. Cerebral Hyperperfusion syndrome which can result in catastrophic haemorrhagic stroke (1% of patients after CEA).

Poor intraoperative blood pressure control may increase the risk of perioperative complications detailed above. A pragmatic consensus suggests aiming for pre-operative SAP<180 mmHg (and ideally less than 160mmHg or DAP <100 mm Hg) in patients presenting acutely for CEA.

An early anaesthetic assessment following the decision to operate is essential and should include documentation of the patient’s base line neurology.

A drug history will help determine which medicines should be continued up to the time of surgery. In line with local guidelines, ACE inhibitor and angiotensin-2 receptor antagonists should ideally be withheld on the day of surgery.

Intraoperative blood pressure will be managed by the anaesthetist and will depend on whether the patient is having a general or regional anaesthetic.

Aim: The patient’s normal systolic blood pressure plus up to 20%

A regional technique allows for continuous neurological assessment. This may demonstrate that a degree of relative hypotension is tolerable to an individual.

Post operatively patients should be admitted to PACU for invasive blood pressure monitoring and continued neurological assessment (to be compared with documented preoperative neurology). A minimum period of 4 hours cardiovascular stability is required before discharge should be considered.

Aim: Blood pressure targets are set by the consultant surgeon and anaesthetist with consideration of blood pressure reduction if systolic pressure >170 mmHg or 160 mmHg if associated with symptoms. Symptoms include unilateral headache, visual disturbances, seizures, or new neurological deficit.

Target blood pressure aim: less than 140mmHg. The speed of reduction will be dependent on the presence or absence of neurological signs and symptoms.

The patient must remain in PACU whilst first line vasoactive drugs are in use. If second line drugs (hydralazine/GTN) are needed the patient should be admitted to ITU/HDU. After weaning from any treatment medications there is a risk of rebound hypertension – the patient should therefore be monitored for a further 4 hours to ensure on going cardiovascular stability.

Management of Post-operative Hypertension in PACU

Systolic BP > 170 mmHg, or 160mmHg if associated with symptoms OR greater than the limits set by the surgeon and anaesthetist

TARGET AIM SAP <140 mmHg

• Sit the patient up in bed and ensure pain is adequately managed and the patient is not in urinary retention

• Check the patient has received all regular antihypertensive medications - Consider administration of omitted drugs

First line pharmacological control: LABETALOL

• Labetalol 100 mg ampule = 5mg /ml

• Give 10 mg (2ml bolus) slowly every 2 mins up to a maximum of 100 mg (over 20 minutes)

• If BP decreases and does not rebound -> regular BP observations

• If BP decreases and then increases again start an infusion at 5 – 200 mg/hr – titrating to BP.
  The patient should be admitted to ITU

Second Line: HYDRALAZINE (for ITU/HDU)

• 20 mg hydralazine in 20mls 0.9% saline (= 1 mg/ml)

• Give 2 mg - 10 mg by slow intravenous injection. If necessary, a repeat injection can be given after an interval of 20-30 minutes

• If BP remains elevated after 25 mins move to third line agent

• If BP decreases and does not rebound continue regular BP observations

• If BP decreases initially but increases again, move to 3^rd line agent

Third Line: Glyceryl Trinitrate (GTN) (for ITU/HDU)

• 50mg GTN in 50ml (1 mg/ml)
  Start infusion at 1-20ml/hr, titrated to BP

Systolic blood pressure below the lower limit set by surgeon and anaesthetist

• Assess fluid balance – consider blood loss, perioperative fluid replacement and other causes of hypotension
  Commence IV fluids – give boluses of 250mls crystalloid titrated against blood pressure up to a maximum of one litre

• In the event of a precipitous fall in blood pressure give fluids in combination with 100 microgram boluses of phenylephrine (see below for dilution) up to a maximum of 10 boluses = 1mg

Consider infusion of either phenylephrine or metaraminol
Phenylephrine (10 mg of phenylephrine in 100mls 0.9% NaCl = 100 micrograms/ml) infusion 0–30 mls/hour and titrate against blood pressure
Metaraminol infusion (20 mg/40mls 0.9% NaCl = 0.5 mg/ml) and titrate to blood pressure – suggested range 0.5-20 ml/hr

Systolic BP >160 and associated with headache/seizure or new neurological deficit – recognise that this is a surgical emergency

• Treatment should start immediately on the ward using non-invasive monitoring

• Antihypertensive treatment should invoke the PACU protocol

• On call vascular specialist trainee must call vascular surgical consultant and ITU consultant or trainee to arrange urgent transfer to PACU or ITU for invasive arterial BP monitoring and blood pressure management

• Consider administration of 8 mg iv dexamethasone stat

National Institute for Health and Care Excellence [NICE] (2022) Stroke and transient ischaemic attack in over 16s: diagnosis and initial management. NG128.

Stoneham, M. D. and Thompson, J. P. (2009) 'Arterial pressure management and carotid endarterectomy', British Journal of Anaesthesia, 102(4), pp. 442-452. Available at: https://doi.org/10.1093/bja/aep012 (Accessed: 19 January 2024)

GALA Trial Collaborative Group (2008) 'General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial', The Lancet, 372(9656), pp. 2132-2142. Available at: https://doi.org/10.1016/S0140-6736(08)61699-2 (Accessed: 19 January 2024).

Useful Link

https://www.nice.org.uk/guidance/conditions-and-diseases/cardiovascular-conditions/stroke-and-transient-ischaemic-attack

This guideline has been registered with the Trust. However, clinical guidelines are guidelines only. The interpretation and application of clinical guidelines will remain the responsibility of the individual clinician. If in doubt, contact a senior colleague or expert. Caution is advised when using guidelines after the review date.

This guideline is for use in Frimley Health NHS Foundation Trust hospitals only. Any use outside this location will not be supported by the Trust and will be at the risk of the individual using it.

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