When a stroke occurs, parts of the brain are damaged and can begin to die within minutes. Therefore, prevention, diagnosis and therapeutic action must be immediate.
Despite this, each year, nearly 800,000 people have a stroke, more than 140,000 die, and many survivors are left with disabilities.
So much so that one in 20 adult deaths is due to stroke; according to CDC data, about 80% could have been prevented.
When a stroke occurs, parts of the brain are damaged and can begin to die within minutes. Therefore, prevention, diagnosis and therapeutic action must be immediate.
In any high-risk procedure, including neurosurgery, hemodynamic monitoring is fundamental in guiding treatment and acting early to avoid possible complications that put the patient’s life at risk.
STROKE: PATHOPHYSIOLOGY
A stroke is an abrupt neurological outburst caused by impaired perfusion through blood vessels to the brain. It can be ischemic or hemorrhagic.
ISCHEMIC STROKE
Ischemic stroke is caused by poor blood and oxygen supply to the brain. Ischemic occlusion leads to thrombotic and embolic conditions in the brain.
Thrombosis
When thrombosis occurs, blood flow is affected by the narrowing of the vessels due to atherosclerosis. The plaque buildup will eventually constrict the vascular chamber and form clots, leading to a thrombotic stroke.
Embolism
In an embolic stroke, decreased blood flow to the brain causes a stroke. Blood flow to the brain is reduced, causing severe stress and premature cell death, and necrosis. 3
Necrosis is followed by rupture of the plasma membrane, inflammation of the organelles, leakage of cellular contents into the extracellular space, and loss of neuronal function.
BRAIN-VASCULAR HEMORRHAGIC ACCIDENT
Hemorrhagic stroke is caused by bleeding or leaking blood vessels. It accounts for approximately 10-15% of all strokes and has a high mortality rate.
Stress to brain tissue and internal injuries cause blood vessels to rupture. It produces toxic effects on the vascular system, which leads to a heart attack. We can differentiate between intracerebral and subarachnoid haemorrhages.
intracranial haemorrhage
In intracranial haemorrhage, blood vessels rupture, causing an abnormal accumulation of blood within the brain. The leading causes that can influence the occurrence of intracranial haemorrhage are hypertension, alteration of the vasculature and the excessive use of anticoagulants or thrombolytic agents.
Subarachnoid haemorrhage
In subarachnoid haemorrhage, blood collects in the subarachnoid space of the brain due to a head injury or brain aneurysm.
NEUROSURGERY COMPLICATIONS
Complications contribute substantially to the increased morbidity and mortality of patients after neurosurgical interventions. Therefore, one of the main objectives of neurosurgeons during perioperative and operative care is to minimise complications.
The most common complications that we can find will depend on the type of cranial surgery we are facing. However, in general, the most common complications of neurosurgery are:
- Postoperative bleeding requires transfusions, the need for a second intervention or the impossibility of removing the patient from mechanical ventilation. two
- Intracranial haemorrhage.
- Brain ischemia.
- Brain oedema.
- Hyperperfusion syndrome.
- Cranial nerve palsies.
- Aseptic meningitis.
FLUID THERAPY IN NEUROSURGERY
In patients undergoing neurosurgery, fluid management plays a fundamental role.
The main goal of fluid management in neurosurgery is the maintenance of normovolaemia and preventing reduced serum osmolarity.
A correct choice of the amount to be administered will help us maintain normovolaemia. Meanwhile, to avoid a decrease in serum osmolarity, the choice of fluid will be essential.
BASIC PRINCIPLES IN NEUROSURGERY FOR THE CHOICE OF THE FLUID TO ADMINISTER
The general principle of fluid therapy for neurosurgery is to maintain an average blood volume and avoid a decrease in plasma osmolarity.
In a normal blood-brain barrier, the water movement between the plasma and the brain is primarily influenced by the osmotic gradient. Therefore, in neurosurgery, fluid osmolarity is essential to prevent cerebral oedema.
In this pathology, a rupture of the blood-brain barrier can occur, developing cerebral oedema, which is why the appearance of dehydration and hydro electrolytic disorders (mannitol, hypertonic saline) is standard.
In addition, we can find disorders such as diabetes insipidus, salt-wasting syndrome, and syndrome of inadequate ADH secretion.
Fluid therapy should be based on maintaining a balance between the heart and the brain. Since, in case of rupture of the blood-brain barrier, excessive fluid intake can aggravate cerebral oedema and, if insufficient, can lead to inadequate tissue perfusion.
What fluid to administer?
Avoid hypotonic solutions. The low osmolarity of the plasma can cause cerebral oedema; therefore, to minimise the accumulation of cerebral fluid, hypotonic solutions such as Ringer’s Lactate should be avoided.
Normal saline reduces the risk of cerebral oedema. Normal saline is an isotonic crystalloid widely used in neurosurgery because it is considered a great option to reduce the risk of cerebral oedema. However, since it has equal amounts of sodium and chloride (154 mEq/L), hyperchloremic metabolic acidosis may occur when a large part is administered since its chloride concentration is higher than the average plasma chloride concentration (96-106 mEq). /L).
Isotonic crystalloids to replace extracellular fluid losses secondary to diuresis and insensible losses. Use Physiological Serum and Plasmalyte at a rate not exceeding 1 ml/kg/hour.
Isooncotic solutions for blood loss. Haemoglobin levels should be maintained at around 8-10 g/dl. This figure should be adjusted depending on the needs of the patient. Red blood cells are the only thing that does not leave the capillary after the blood-brain barrier is broken.
Avoid solutions containing glucose. Hyperglycemia aggravates the neurological prognosis. Therefore, except in diabetic patients, the administration of glucose or insulin should be avoided.
Dextrans and starches in large amounts increase the risk of coagulopathy. There is no clear evidence for the administration of synthetic colloids in neurosurgery.
Monitor serum osmolarity. Do not exceed 320 mOsm/L due to the risk of kidney failure.