What are the 2024 guidelines for using Transcranial Doppler (TCD) and Intracranial Pressure (ICP) monitoring in stroke patients?

2024 Guidelines for TCD and ICP Monitoring in Stroke Patients

Current guidelines recommend ICP monitoring primarily for patients with decreased consciousness, evidence of transtentorial herniation, significant intraventricular hemorrhage, or hydrocephalus, while TCD has limited accuracy for stenosis detection but remains useful for monitoring cerebral hemodynamics and treatment response in stroke patients. 1

Intracranial Pressure (ICP) Monitoring in Stroke

Indications for ICP Monitoring

• ICP monitoring should be considered in patients with Glasgow Coma Scale (GCS) score ≤8, clinical evidence of transtentorial herniation, significant intraventricular hemorrhage (IVH), or hydrocephalus 1
• A cerebral perfusion pressure (CPP) of 50-70 mmHg is reasonable to maintain, depending on the status of cerebral autoregulation 1
• Ventricular drainage is recommended as treatment for hydrocephalus, especially in patients with decreased level of consciousness 1

ICP Monitoring Devices and Considerations

• Two main types of ICP monitoring devices are used:
  • Ventricular catheters (VC): Allow both monitoring and therapeutic CSF drainage 1
  • Parenchymal catheters: Allow monitoring only, but with potentially lower risk of infection and hemorrhage 1
• Before insertion of any monitoring device, the patient's coagulation status should be evaluated 1
• Prior use of antiplatelet agents may justify platelet transfusion, and warfarin use may require coagulopathy reversal before placement 1

Management of Elevated ICP

• Initial management steps include:
  • Elevate the head of the bed to 20-30 degrees to help venous drainage 2
  • Ensure proper airway management with tracheal intubation and mechanical ventilation when necessary 2
  • Avoid hypoxia, hypercarbia, and hyperthermia 2
  • Restrict fluids mildly and avoid hypo-osmolar fluids 2
• Hypertonic saline (3%) has demonstrated rapid ICP reduction in patients with clinical transtentorial herniation 2
• Corticosteroids should NOT be administered for treatment of elevated ICP in intracerebral hemorrhage (ICH) 1

Transcranial Doppler (TCD) in Stroke Management

Clinical Applications of TCD

• TCD can detect intracranial vessel abnormalities, including occlusions and stenoses, though with lower accuracy than CTA and MRA 1
• TCD has shown ability to predict and enhance intravenous rtPA outcomes in acute ischemic stroke 1
• Large-vessel occlusions and proximal occlusions identified by TCD predict poor revascularization results with intravenous rtPA and worse clinical outcomes 1
• TCD provides continuous, real-time imaging that can determine timing of recanalization and occurrence of reocclusion 1

TCD for ICP Assessment

• Increased ICP and decreased CPP give rise to characteristic changes in the Doppler waveform, specifically a decrease in diastolic velocity and an increase in the pulsatility index 1, 3
• The pulsatility index (PI) can serve as a surrogate marker for ICP, with serial measurements being more valuable than single readings 3
• Recent research has shown high correlation between TCD-derived critical closing pressure and other measures of ICP 4

Limitations of TCD

• TCD accuracy is less than that of CTA and MRA for steno-occlusive disease, with sensitivity ranging from 55% to 90% and specificity from 90% to 95% 1
• The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) Trial found that TCD could positively predict only 55% of angiographically confirmed stenoses 1
• TCD is more accurate for proximal M1 than distal M1 or M2 disease 1
• Usefulness is limited in patients with poor bony windows, and accuracy depends on technician experience, interpreter skill, and patient vascular anatomy 1
• For posterior circulation stroke, Doppler ultrasound has limited utility 1

Clinical Signs of Increased ICP

• Key signs of increased ICP include declining consciousness, focal neurological deficits, abnormal pupillary responses, and abnormal posturing 5
• Headache (often severe and worsening with Valsalva maneuvers), nausea, projectile vomiting, and visual disturbances are common symptoms 5
• Papilledema may be visible on fundoscopic examination, though it may be absent in acute onset despite significantly elevated ICP 5
• Diagnostic criteria include lumbar puncture opening pressure >200 mm H₂O and neuroimaging findings such as disappearance of cerebral ventricles, brain midline shift over 5 mm, and compression of basal cisterns 5

Important Caveats and Pitfalls

• Despite intensive medical management including osmotic therapy, mortality rates in patients with increased ICP remain as high as 50-70% 2
• ICP interventions should be considered temporizing measures that extend the window for definitive treatments 2
• No evidence indicates that hyperventilation, corticosteroids, diuretics, mannitol, or glycerol alone improve outcomes in patients with ischemic brain swelling 2
• The absence of published studies showing that management of elevated ICP affects ICH outcome makes the decision whether to monitor and treat elevated ICP unclear in many patients 1
• Clinical signs of herniation may precede increases in ICP, highlighting the importance of close clinical monitoring alongside instrumental measurements 6