Continuous Neurological Monitoring of Patients

Introduction

Continuous Neurological Monitoring of Patients is one of the priority functions of the neurological intensive care unit nurses is to monitor the critically ill patients. This provides clues about the patient’s prognosis and helps in clinical evaluation of critical, unconscious, or comatose condition.

Definition

Continuous monitoring refers to the ongoing clinical assessment of patients with neurological disorders using noninvasive, invasive, or combined modalities to identify vital neurological changes which may be crucial for timely and effective management.

Purposes

• For early identification of pathophysiological changes.
• To initiate interventions at the right time.
• To minimize complications.
• To prevent deterioration and secondary injury.
• To reduce mortality.

Indications

• Patients with increased ICP due to traumatic brain injury (TBI), aneurysmal subarachnoid hemorrhage, cerebellar strokes, encephalitis, and fulminant hepatic failure.
• Postoperative patients in neurosurgical intensive care.
• Patients with induced coma for status epilepticus or intracranial hypertension.
• Post-cardiac arrest patients with seizure.

Types of Monitoring

• Noninvasive monitoring: Noninvasive monitoring includes ECG, noninvasive BP measurement, pulse oximetry, and capnography measurement.
• Invasive monitoring: It includes systemic arterial, central venous, and PA pressure measurements.
• Multimodal monitoring: It includes simultaneous monitoring of multiple physiological parameters that aid in understanding real-time brain physiology. For example, ICP monitors and transcranial Doppler (TCD).

Modalities for Continuous Monitoring

• Continuous Video EEG Monitoring

This method can be applied for ruling out subclinical or nonconvulsive seizures, characterizing paroxysmal clinical events, detecting cerebral ischemia, guiding medication titration, and quantifying seizure frequency in patients with status epilepticus.

• Intracranial Pressure Monitoring

This can be assessed by various methods.

• Brain Tissue Oxygenation

Brain tissue oxygen tension (PbtO₂) is a marker of the balance between oxygen delivery and oxygen consumption in the brain. A parenchymal probe is placed directly in the least-injured hemisphere of the brain tissue for measuring PbtO₂ in patients with TBI.

• Normal values: Range from 25 to 35 mmHg.
• Completed infarction or dead brain tissue: Less than 5 mmHg.
• Possible regions that are at risk: 5-25 mmHg.

• Cerebral Microdialysis

A miniature micro dialysis catheter placed in the brain parenchyma can offer additional insight into the microenvironment and cellular metabolism. This can be used for measuring the levels of glucose, lactate, pyruvate, glycerol, and glutamate.

• Multimodal Monitoring

This involves the combined use of the above-mentioned methods for obtaining more advanced clinical information of the brain functions.

Nurse’s Responsibility Related to Monitoring

Monitor Neurological Status

1. Patients with acute neurological problem will be assessed every hour and when necessary, including pupil assessment.
2. Findings are charted in the 24-hour assessment record and neurosection of the critical care flow sheet.
3. Any change in the neurological status is reported to the physician.

Perform Spinal Testing

1. Spinal cord testing is performed when necessary for all trauma patients, especially with head and suspected spinal cord injury, and is continued until cervical-thoracic-lumbar spines are cleared from injuries.
2. It is performed every hour for 24 hours, and then every 1-4 hours for 36 hours for all postoperative aneurysm repairs.
3. It helps to detect paraplegia caused by ischemia to the spinal cord.

Determine Glasgow Coma Score (GCS)

• Assess GCS, document in the graphic record, and report changes in the GCS to a physician.

Monitor the Patient with Raised ICP

• For acute patients with/at risk for raised ICP, report any changes promptly to the physician as additional monitoring is required as follows:
• Monitor core temperature every hour. Continuous monitoring should be considered if cooling blankets and/or neuromuscular blockers are in use.
• Monitor BP and HR carefully.
• Monitor blood gases every 6 hours and as and when required (PRN) during the acute phase.
• If mannitol is ordered or hypertonic saline is used, measure serum electrolytes and osmolalities every 6 hours as ordered. The normal range of serum osmolality is 285-295 mOsm/kg (285-295 mmol/kg). Notify the neurosurgeon if serum osmolality >320 mmol/kg (when treated with mannitol) or >340 (with hypertonic saline), or if serum sodium is >156 (with hypertonic saline).
• Monitor for increased/dilute urine output. Obtain order for serum and urine electrolytes and osmolality to assess for diabetes insipidus.
• Monitor carefully for signs of seizure activity.
• Monitor blood sugar closely. Review target glucose with the physician if insulin is required for an increase in the lower limit range.
• Monitor for seizure activity.

Monitor Intraventricular Pressure

• The registered nurse is responsible for the setup, zeroing, leveling, and maintenance of an ICP monitoring circuit.
• Monitor waveform continuously.
• Record mean ICP on neurosection of flow sheet, every hour or PRN as required.
• Position ICP drain at the level ordered by the neurosurgeon (e.g. 15 cm above the external auditory meatus). Calculate cerebral perfusion pressure (CPP) with each recorded ICP.
• ICP drainage goal is ~<20 mL/h.
• CPP = MBP – Mean ICP
• Normal ICP is 5-15 mmHg.
• Normal CPP is 60-80 mmHg.
• CPP <50 mmHg may indicate a significant reduction in cerebral blood flow.

Monitor Lumbar CSF

• The nurse is responsible for the setup, zeroing, leveling, and maintenance of a lumbar CSF monitoring circuit. Level the transducer to the iliac crest.
• Assess dressing and drain at the start of each shift and document in the 24-hour assessment record. Record the mean CSF pressure every hour on neurosection of the critical care flow sheet.
• If pressure remains >10-15 mmHg or higher than the range specified by the physician, notify the vascular surgeon.
• Monitor pedal pulses, pain, sensation (pin and light touch), and proprioception every hour for 24 hours. If normal function is present, continue to monitor every 2-4 hours for 3 days or as ordered.
• Document the findings in the spinal cord testing record.

REFERENCES

1. Annamma Jacob, Rekha, Jhadav Sonali Tarachand: Clinical Nursing Procedures: The Art of Nursing Practice, 5th Edition, March 2023, Jaypee Publishers, ISBN-13: 978-9356961845 ISBN-10: 9356961840
2. Omayalachi CON, Manual of Nursing Procedures and Practice, Vol 1, 3 Edition 2023, Published by Wolters Kluwer’s, ISBN: 978-9393553294
3. Sandra Nettina, Lippincott Manual of Nursing Practice, 11th Edition, January 2019, Published by Wolters Kluwers, ISBN-13:978-9388313285
4. Adrianne Dill Linton, Medical-Surgical Nursing, 8th Edition, 2023, Elsevier Publications, ISBN: 978-0323826716
5. Donna Ignatavicius, Medical-Surgical Nursing: Concepts for Clinical Judgment and Collaborative Care, 11th Edition ,2024, Elsevier Publications, ISBN: 978-0323878265
6. Lewis’s Medical-Surgical Nursing, 12th Edition,2024, Elsevier Publications, ISBN: 978-0323789615
7. AACN Essentials of Critical Care Nursing, 5th Ed. Sarah. Delgado, 2023, Published by American Association of Critical-Care Nurses ISBN: 978-1264269884

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