Who requires continuous monitoring?
The level of monitoring required should be assessed on admission, based on criteria related to the severity of the stroke and potential interventions (5). More than one in four stroke patients receive reperfusion therapy with thrombolysis and/or thrombectomy (2). These therapies are effective, but require continuous and standardised monitoring following the procedures. One complication of these therapies is intracerebral haemorrhage. In 2020, around 6 % of patients receiving thrombolytic therapy developed intracerebral haemorrhage and deterioration in function (2). Most of these haemorrhages occur within 12 hours of thrombolysis (6).
Patients admitted to stroke units who have not received reperfusion therapy may develop sudden changes in cerebral function, with loss of function and an indication for thrombolytic therapy. Unstable patients also have a particular requirement for maintenance of optimal blood pressure, circulation and respiration. Recent knowledge gained about the importance of good blood pressure control in preventing complications has increased the focus on closer monitoring of blood pressure (7). Cerebral blood circulation can be monitored by repeated ultrasound scans, which makes it possible, for instance, to observe whether reperfusion occurs following intravenous thrombolysis or whether a revascularised vessel becomes reoccluded (8). Cardiac arrhythmias such as atrial fibrillation are common in the acute phase and may be seen in approximately 10 % of patients. Atrial fibrillation with rapid heart rate may have an adverse effect on cerebral circulation (9). Infarction of some areas of the brain, e.g. left insular region, increases the risk of cardiac arrhythmias, and patients with these infarctions should receive continuous heart rhythm monitoring for several days.
The level of monitoring required should be assessed on admission, based on criteria related to the severity of the stroke and potential interventions
Dysphagia is seen in 42–67 % of patients and poses a risk of aspiration (10, 11). Pneumonia is one of the main causes of poor prognosis following stroke. Impaired consciousness or paresis of the respiratory and swallowing muscles also increases the risk of acute respiratory difficulties due to accumulation of saliva and mucus formation in the pharynx. These patients often require continuous monitoring of respiration and frequent removal of saliva and mucus to avoid serious respiratory problems.
Some patient groups may have unstable neurological function, regardless of reperfusion treatment. These patients include those with stenosis of the carotid or intracranial arteries and those with critical circulation in cerebral microvessels not accessible for intervention. Patients with oedema in and around the infarction who are at risk of raised intracranial pressure or with neurological deficit that may impact consciousness, swallowing function and respiration may also require continuous monitoring. In case of major and moderate cerebral infarction, oedema is an independent risk factor for poorer outcomes following stroke (12). In some patients, the infarction with oedema may result in elevated intracranial pressure and require surgical treatment with craniectomy or drainage of cerebrospinal fluid. For major cerebellar infarctions (> 1/3 of cerebellar hemisphere), there is a risk of both sudden obstructive hydrocephalus and brainstem compression. Craniectomy, both hemicraniectomy and suboccipital craniectomy, improves survival and reduces loss of function (13, 14). Optimal function following infarction depends on craniectomy being performed promptly once treatment has been found to be indicated.
In a few cases of intracerebral haemorrhage, acute neurosurgical treatment may be appropriate, such as external drainage or evacuation of the haematoma. The vast majority of patients with intracerebral haemorrhage do not require surgery, but other acute treatment and monitoring is essential. Suboptimal physiological parameters are also associated with poorer function and increased mortality in acute intracerebral haemorrhage (7).
The size of the haemorrhage is influenced by blood pressure in the first few hours following stroke (15). Therefore, it is absolutely essential to monitor blood pressure and to initiate rapid and targeted treatment with intravenous antihypertensive therapy. This should take place under continuous monitoring. A Danish study from 2021 has demonstrated that around half of patients with intracerebral haemorrhage were using antithrombotic treatment at onset of the haemorrhage (16). Rapid reversal of the anticoagulant effect is appropriate for many of these patients. Complications may also arise suddenly in intracerebral haemorrhage, and neurosurgical treatment may be decisive for the outcome (7).
Other patients requiring close monitoring in the stroke unit are patients with repeated serious transient ischaemic attacks (TIAs). They may suddenly require reperfusion treatment due to carotid artery dissection and stroke with worsening of neurological symptoms.