Compare and contrast the intraventricular catheter and the intra-parenchymal fibre- optic transducer for intracranial pressure monitoring in critically ill patients.
You may tabulate your answer.
|
Intraventricular catheters |
Intra – parenchymal devices |
|
Gold standard for ICP monitoring |
Not a gold standard though fairly accurate |
|
Catheters are Surgically placed into the |
Thin cable with an electronic fibre-optic |
|
Can be rezeroed (re-calibrated)after |
Not possible to re-calibrate after insertion |
|
Accurate provided catheter patent |
Drift leading to inaccuracy particularly after 5 to 7 days |
|
Can drain CSF to treat raised ICP |
No ability to drain CSF |
|
Ventriculitis - a serious life threatening |
Lower risk of Infection |
|
Blocked Catheter and intra-cerebral or intra-ventricular haemorrhage other complications. |
Solid state systems. Less chance of haemorrhage. |
|
Requires special expertise for insertion |
Easier to place |
|
Difficult to insert in patients with collapsed ventricles due to severe cerebral oedema |
Can be inserted in these patients easily |
|
Other indication – Subarachnoid |
Other indications ( controversial) – |
|
Coagulopathy – absolute contraindication |
Coagulopathy – relative contraindication |
|
Cheap |
Expensive |
The college table is fairly comprehensive. One cannot add very much to this list of advantages and disadvantages.
A discussion of EVDs and the indications/contraindications of ICP monitoring can be found here:
Specifically, methods of ICP monitoring are discussed, and a table similar to the above is constructed on the basis of published data. This table is reproduced below:
| EVD | Codman Microsensor |
| Gold standard of ICP monitoring | Similar accuracy to EVD |
| Pressure is transmitted to a Wheatsone bridge transducer via fluid-filled non-compressible tubing | Piesoelectric strain gauge pressure sensor is intracranial; connected to the monitor via fiberoptic cable |
| Requires a certain expertise to place correctly. About 12% areplaced into an inappropriate position. | Requires less expertise to place (however, this should still be done by somebody with neurosurgical experience) |
| More traumatic owing to depth of insertion and diameter of catheter | Less traumatic, because the catheter placement is not as deep, and the catheter tip is finer. The Codmans typically sits about 2cm below the cerebral surface. |
| CSF can be drained though the EVD | CSF cannot be drained or sampled |
| The catheter can become blocked by clots or debris | The catheter cannot block |
| Measures intraventricular pressure, which is thought to be representative of the pressure within the intracranial CSF | Measures local parenchymal pressure |
| Can be re-zeroed to atmorpsheric pressure | Cannot be re-zeroed after insertion; calibration tends to drift after 72 hours |
| Insertion is impossible if the ventricles are collapsed | Does not rely on venticular placement, and thus is the only option in a patient with small collapsed ventricles |
| Dangerous in coagulopathy. Even when non-coagulopathic, the risk of haemorrhagic complications is around 5-7% on average | Coagulopathy is only a relative contraindication; hemorrhagic complications are infrequent. One study puts the rate of bleeding at 1.1%. |
| Places the patient at risk of ventriculitis after 5 days. Bacterial colonisation rates range up to 27%, but studies vary in their definition of what a clinically significant infection actually is. | Less likely to become infected; highly unlikely to cause ventriculitis, as it does not communicate with the entricles. One study puts the infection rate at 0.6%. |
| Cheap | Expensive |
Brean, A., P. K. Eide, and Audun Stubhaug. "Comparison of intracranial pressure measured simultaneously within the brain parenchyma and cerebral ventricles." Journal of clinical monitoring and computing 20.6 (2006): 411-414.
Raboel, P. H., et al. "Intracranial pressure monitoring: invasive versus non-invasive methods—a review." Critical care research and practice 2012 (2012).
Lozier, Alan P., et al. "Ventriculostomy-related infections: a critical review of the literature." Neurosurgery 51.1 (2002): 170-182.
Saladino, Andrea, et al. "Malplacement of ventricular catheters by neurosurgeons: a single institution experience." Neurocritical care 10.2 (2009): 248-252.
Bekar, A., et al. "Risk factors and complications of intracranial pressure monitoring with a fiberoptic device." Journal of Clinical Neuroscience 16.2 (2009): 236-240.
Khan, S. H., et al. "Comparison of percutaneous ventriculostomies and intraparenchymal monitor: a retrospective evaluation of 156 patients."Intracranial Pressure and Neuromonitoring in Brain Injury. Springer Vienna, 1998. 50-52.