Inaccurate pressure readings for subarachnoid bolts

Area of Science:

• Neurosurgery
• Neurology
• Critical Care Medicine

Background:

• The subarachnoid bolt is a common device for monitoring intracranial pressure (ICP) in various neurological conditions.
• Accurate ICP monitoring is vital for managing patients with severe brain injuries and preventing secondary brain damage.

Observation:

• Two cases are presented where functional subarachnoid bolts failed to detect elevated intracranial pressure.
• Case 1: A patient with Reye's syndrome exhibited signs of herniation and cardiac arrest, yet the subarachnoid bolt showed normal pressures and waveforms.
• Case 2: A patient with a postoperative epidural hematoma had a subarachnoid bolt indicating low pressure despite clinical and radiological evidence of a growing mass.

Findings:

• Subarachnoid bolts may provide misleadingly normal intracranial pressure readings despite significant intracranial hypertension.
• The presence of a good waveform on the subarachnoid bolt does not guarantee accurate pressure measurement.
• Autopsy in one case confirmed herniation, contradicting the subarachnoid bolt's readings.

Implications:

• Relying solely on subarachnoid bolt readings can lead to delayed or missed diagnoses of critical conditions.
• Frequent clinical assessment of neurological status is indispensable and should not be superseded by ICP monitor data.
• These findings highlight the limitations of subarachnoid bolt technology and emphasize the need for vigilant clinical evaluation in neurocritical care.