VOL: 97, ISSUE: 35, PAGE NO: 28
Juliet Bostwick, MSc, RGN, is lecturer practitioner, Oxford Brookes University/Oxford Radcliffe Hospital NHS Trust
Mary Sneade, BA, RGN, RM, is assistant trial manager, Oxford Radcliffe Hospital NHS TrustSubarachnoid haemorrhage - bleeding into the subarachnoid space around the brain - is usually the result of a burst cerebral aneurysm. It can require invasive treatment to manage some of the complications.
Subarachnoid haemorrhage - bleeding into the subarachnoid space around the brain - is usually the result of a burst cerebral aneurysm. It can require invasive treatment to manage some of the complications.
Table 1 lists the complications of aneurysmal SAH which contribute to morbidity and mortality and may require specific treatment.
If the patient survives the initial bleed, one of the main causes of subsequent death is rebleeding. The peak incidence of rebleeding occurs within 48 hours of the initial event and the risk of further rupture remains high over the following two weeks.
Early diagnosis, transfer to a specialist unit, cerebral angiography and prompt treatment plus appropriate nursing care are essential to reduce the risk of rebleeding.
Arterial vasospasm occurs in up to 60% of aneurysmal SAH patients. Of these, about 20% are symptomatic with neurological deterioration.
It is likely that a breakdown product of the blood causes spasms in the surrounding vessels which lead to vasoconstriction and reduced cerebral blood flow. The more blood found in the subarachnoid space, the higher the incidence of vasospasm.
Neurological symptoms linked to vasospasm are often intermittent and can vary markedly in severity. They may include an alteration in the level of consciousness, weakness in one or more limbs, or expressive and receptive dysphasia.
Table 2 outlines the essential components in the management of vasospasm. Triple-H therapy and the use of inotropes is initiated in the high-dependency or intensive care unit, but care will need to be continued on the wards.
Untreated arterial vasospasm is one of the main causes of cerebral ischaemia, which in turn can lead to cerebral infarction, permanent disability or death.
Hydrocephalus is an abnormal accumulation of cerebrospinal fluid in the ventricles of the brain. After an SAH the extra-arterial blood impedes the natural absorption of cerebrospinal fluid, creating a communicating hydrocephalus. A blood clot in the ventricular system will cause an obstructive hydrocephalus.
The symptoms include a change in the level of consciousness, which may be acute, confusion and headaches of varying severity.
Hydrocephalus may occur almost immediately after an SAH or may develop later. Diagnosis can be made by a computed tomography scan, which will show enlarged ventricles, or by increased pressure on lumbar puncture.
Where possible, the aneurysm should be secured before the hydrocephalus is treated. This is because treatment of the hydrocephalus will reduce the build-up of cerebrospinal fluid, which in turn will lower the intracranial pressure. This sudden change may cause an unsecured aneurysm to rebleed.
Once the aneurysm has been secured, a communicating hydrocephalus may be treated with a single or series of lumbar punctures. Obstructive hydrocephalus may be treated with the insertion of a ventricular drain. Persistent hydrocephalus may require the insertion of a ventriculo-peritoneal shunt.
Treatment of cerebral aneurysm
The standard method of treatment is surgical exposure of the aneurysm via craniotomy, with the application of a titanium clip to the neck of the aneurysm to occlude it from the circulation (Fig 1).
When to operate is a complex decision that depends on the age of the patient, the site and size of the aneurysm, the grade of the bleed and the patient's general condition. Surgery carries risks of morbidity and mortality and the decision to operate should be taken only after discussion with the patient and members of his or her family.
Early diagnosis of an SAH is important as surgeons advocate treatment in WFNS (World Federation of Neurological Surgeons) grade I to III patients as soon as possible, usually within the first four days of ictus (Hutchinson et al, 1998).
Endovascular coiling was developed in the early 1990s and is performed by specialist neuroradiologists for the treatment of both ruptured and unruptured aneurysms. The procedure takes place in the radiology department using digital subtraction angiography to guide the coils into the aneurysm.
Platinum coils are placed into the aneurysm sac via a microcatheter which has been fed through the groin via the femoral artery and up into the arterial cerebral circulation. The first coil forms a basket inside the aneurysm, which then catches additional coils as they are placed inside (Fig 2).
Once in position the coils form a thrombus and the clot isolates the aneurysm from the arterial circulation. More than one aneurysm may be treated at the same time. The patient usually has follow-up angiography after six months to check the occlusion of the aneurysm.
The Medical Research Council is funding a large multicentre prospective randomised controlled trial (RCT) comparing the neurosurgical and endovascular treatment of patients with ruptured intracranial aneurysms. The International Subarachnoid Aneurysm Trial is being coordinated from the Radcliffe Infirmary in Oxford (website: http://users.ox.ac.uk/~isat).
More than 40 participating centres in the UK, Europe, North America and Australia have currently recruited about 1,700 patients. This study is already the largest prospective RCT in the management of aneurysmal SAH and the results will be extremely important in determining the future management of patients after an SAH.
Nurses caring for those who have had an SAH must keep their knowledge and skills up to date as they can play a vital role in the care and management of these critically ill patients.
- The first article in this series was published in Nursing Times last week.