How to improve the health of an injured brain. The specific case of Stroke.

Stroke is not uncommon during perianaesthetic period, favoured by temporal antithrombotic withdrawal, and also caused by surgical or endovascular procedures or sometimes even anaesthesia itself.
Early identification of stroke can be challenging particularly after general anaesthesia. Besides classical symptoms, abnormal delay of emergence, especially with tonus asymmetry, should lead to prompt local stroke procedure. Stroke neurologist should be involved as soon as a potential stroke is detected, preferentially before first brain imaging. Since no pathognomonic clinical sign or symptom may differentiate acute ischaemic stroke (AIS) from intracerebral haemorrhage (ICH), brain imaging is urgent.
Before imaging, bet on AIS but do not jeopardize an ICH. As most of strokes (including perioperative) are ischaemic, all suspicion of stroke should be considered as ischaemic until proven otherwise. Lying-flat position (debated) and not lowering hypertension (unless > 220/120 mmHg or necessary for a specific comorbid condition) may favour cerebral perfusion and collaterality recruitment in AIS. Conversely, antithrombotic initiation prior to exclusion of ICH by imaging must be prohibited. In both AIS and ICH, hyperthermia, hypo/hyperoxia, hypo/hyperglycaemia should be avoided/corrected (1–4).
First line of AIS treatment is intravenous thrombolysis (IVT). It should to be initiated within 4.5 hours after stroke onset (SO) (5), but can be administered up to 9 hours in case of a significant CT or MR perfusion mismatch (6). Stroke with unknown onset (including wake-up strokes) can also benefit from IVT in presence of a MRI DWI/FLAIR (7) or perfusion significant mismatch (6). Often contraindicated to IVT, mostly because of recent surgery, post-anaesthetic patients may still benefit from endovascular procedures.
Mechanical thrombectomy (MT) started within 6 hours of SO, with (< 4.5h (-9h)) or without (out of delay or general contraindication) prior IVT, significantly reduces morbimortality of IS with an anterior large vessel occlusion (LVO) (8–12). MT can also be successful up to 24 hours after SO in patients showing a significant radiological (i.e. perfusion) or clinic-radiological mismatch (13,14). Thus, prior appropriately tailored cerebral imaging is mandatory to screen for LVO, approximate SO when unknown, or identify the slow ischemic stroke progressors. Choice of anaesthesia method during MT remains controversial. Randomised control trials and meta-analyses recently suggested that protocol-driven general anaesthesia, as compared to conscious-sedation, may be associated with better recanalization rates and functional outcomes (15,16). In any case, key anaesthetic goals should be shortening door-to-groin puncture and maintaining adequate blood pressure (17–19).
Although time-window of early revascularization treatments has been extended, one should remind that “having more time” does not mean one “should take more time”. The sooner IVT and/or MT are applied, the greater their efficacy and safety.

Early medical management of ICH aims at limiting haematoma progression by half-sitting position (debated)(2), early intensive hypertension lowering (systolic target < 140 mmHg in < 1h) (20), discarding antithrombotics and reversing anticoagulants when present (4). Implementing intra-hospital goal-directed care bundle protocols with algorithms for the management of blood pressure, glycemia, temperature and coagulation, may improve ICH outcome (21). Long regarded as disappointing, neurosurgery has finally been revealed promising with minimally invasive removal of acute ICH (ENRICH trial 2023, not yet published).
Admitted neuroprotective interventions at subacute phase of AIS and ICH still rely on maintenance of normal oxygenation, temperature and glycaemia. Hypothermia, corticosteroids and systematic antiepileptic prophylaxis are not recommended (3,4). After IS, adequate blood pressure targets may help to recruit collaterality when still necessary (absent or incomplete recanalization) and to limit haemorrhagic complications of IVT and/or MT (1,2).

Prevention and early detection of stroke complications also remains essential because of their negative impact on final outcome. Neurological and non-neurological complications are currently associated with clinical neurological worsening. Avoidance of unnecessary prolonged sedation and regular NIH Stroke Scale follow-up may enlarge the clinical sensitivity. Particular attention should be paid to screen deglutition disorders in order to prevent aspiration pneumonia (3,4). After AIS, algorithms based on infarct volume or severity are useful to guide the timing of anticoagulation in order to limit the risk of symptomatic haemorrhagic transformation (22).