True Intracranial Pressure Research Articles

Global traumatic brain injury intracranial pressure: from monitoring to surgical decision.

Traumatic brain injury (TBI) is a significant global public health issue, heavily impacting human health, especially in low-and middle-income areas. Despite numerous guidelines and consensus statements, TBI fatality rates remain high. The pathogenesis of severe TBI is closely linked to rising intracranial pressure (ICP). Elevated intracranial pressure can lead to cerebral herniation, resulting in respiratory and circulatory collapse, and ultimately, death. Managing intracranial pressure (ICP) is crucial in neuro-intensive care. Timely diagnosis and precise treatment of elevated ICP are essential. ICP monitoring provides real-time insights into a patient's condition, offering invaluable guidance for comprehensive management. ICP monitoring and standardization can effectively reduce secondary nerve damage, lowering morbidity and mortality rates. Accurately assessing and using true ICP values to manage TBI patients still depends on doctors' clinical experience. This review discusses: (a) Epidemiological disparities of traumatic brain injuries across countries with different income levels worldwide; (b) The significance and function of ICP monitoring; (c) Current status and challenges of ICP monitoring; (d) The impact of decompressive craniectomy on reducing intracranial pressure; and (e) Management of TBI in diverse income countries. We suggest a thorough evaluation of ICP monitoring, head CT findings, and GCS scores before deciding on decompressive craniectomy. Personalized treatment should be emphasized to assess the need for surgical decompression in TBI patients, offering crucial insights for clinical decision-making.

Intracranial Pressure Values Are Highly Variable After Cerebral Spinal Fluid Drainage.

Intracranial pressure (ICP) is often obtained via external ventricular drain (EVD) placement and is discussed as a key vital sign in neuroscience. Nurses are most often delegated the task of observing, adjudicating, and documenting ICP. Cerebrospinal fluid drainage requires that the transducer connected to the EVD is open to drain, prohibiting ICP monitoring. There are no recent data to support an evidence-based standard for the period an ICP waveform should be observed, after the EVD is clamped, to be able to adjudicate a value that represents the patient's status. Therefore, the purpose of this study is to determine the optimal period for which an EVD should be closed to obtain an accurate ICP value. In a sample of 30 subjects who received continuous ICP monitoring for 15 minutes, there was no universal pattern to ICP after clamping an EVD. The conditional probability of observing a patient's highest ICP, if ICP is observed for 5 minutes, is 0.0181. The conditional probability increased to 0.0402 if ICP is observed for 10 minutes. There were no instances of ICP elevation requiring intervention. The results suggest that at least 5 minutes of ICP monitoring is safe and is required to provide an ICP value that reflects true ICP.

The best marker for guiding the clinical management of patients with raised intracranial pressure-the RAP index or the mean pulse amplitude?

Raised intracranial pressure is a common problem in a variety of neurosurgical conditions including traumatic brain injury, hydrocephalus and intracranial haemorrhage. The clinical management of these patients is guided by a variety of haemodynamic, biochemical and clinical factors. However to date there is no single parameter that is used to guide clinical management of patients with raised intracranial pressure (ICP). However, the role of ICP indices, specifically the mean pulse amplitude (AMP) and RAP index [correlation coefficient (R) between AMP amplitude (A) and mean ICP pressure (P); index of compensatory reserve], as an indicator of true ICP has been investigated. Whilst the RAP index has been used both as a descriptor of neurological deterioration in TBI patients and as a way of characterising the compensatory reserve in hydrocephalus, more recent studies have highlighted the limitation of the RAP index due to the influence that baseline effect errors have on the mean ICP, which is used in the calculation of the RAP index. These studies have suggested that the ICP mean pulse amplitude may be a more accurate marker of true intracranial pressure due to the fact that it is uninfluenced by the mean ICP and, therefore, the AMP may be a more reliable marker than the RAP index for guiding the clinical management of patients with raised ICP. Although further investigation needs to be undertaken in order to fully assess the role of ICP indices in guiding the clinical management of patients with raised ICP, the studies undertaken to date provide an insight into the potential role of ICP indices to treat raised ICP proactively rather than reactively and therefore help prevent or minimise secondary brain injury.

Clinical Trials in Decompressive Craniectomy After Severe Diffuse Traumatic Brain Injury

C m t d i o r q T he recently published results of the DECRA (DEcompressive CRAniectomy) trial (7) have stimulated much discussion about the role of decompressive surgery in the etting of severe traumatic brain injury (TBI). Although decomressive craniectomy after severe diffuse TBI has been shown to educe intracranial pressure (ICP) and thereby facilitate mainteance of cerebral perfusion, the optimal timing, target population, nd effect on survivor outcome of decompression remain topics f debate. Recent studies have attempted to answer these uestions, but there is still a paucity of evidence and no concluive recommendation for lifesaving surgery in the setting intraranial hypertension after TBI. Even guidelines on ICP thresholds or hypertension and refractory hypertension are vague, usually iven as a range from 20–25 mg (3). In addition, using simple hresholds without consideration of true ICP burden is problemtic. The field of neurosurgery requires evidence-based answers o these questions now more than ever, as trauma is a leading ause of death in the first 40 years of life worldwide, with almost 0% of incidents involving the head (1).

Erroneous Intracranial Pressure Measurements From Simultaneous Pressure Monitoring and Ventricular Drainage Catheters

The objective of this report is to highlight the potential for false pressure measurements from systems that combine intracranial pressure (ICP) measurement and ventricular drainage. If the ports of the drain become blocked to the extent that they present a high resistance to cerebrospinal fluid flow, then a significant pressure gradient between the inside and outside of the catheter may be established. Thus, any intracatheter transducer will faithfully record a pressure much lower than true ICP. This holds true for catheter-tip transducers when the transducer lies inside the catheter. In the absence of flow, however, pressures will equalize; therefore, accurate measurements may be taken if the drain is temporarily closed. We model this situation and provide simulations of expected measurements in such situations; these compare well to observed clinical readings.

Fiberoptic intraparenchymal brain pressure monitoring with the Camino V420 monitor: reflections on our experience in 163 severely head-injured patients.

To assess the safety and accuracy of the Camino intraparenchymal sensor, we prospectively evaluated hemorrhagic complications, zero-drift, infection, and system malfunction in 163 patients monitored after a severe head injury. Mean duration of intracranial pressure (ICP) monitoring was 5 +/- 2.2 days (range: 12 h to 11 days). Of the 141 patients with a control CT scan, four showed a 1-2-cc collection of blood at the catheter's end. When removed, the sensors underread the true ICP value (negative zero-drift) in 80 of the 126 sensors evaluated (63.5%). Fourteen sensors showed no zero-drift, and 32 sensors overread the true ICP value (positive zero-drift) (median: -1 mm Hg; interquartile range: -4 to +1 mm Hg). No significant relationship was found between zero-drift, the surgeon who implanted the sensor, intracranial hypertension, or duration of ICP monitoring. No clinical infections could be attributed to the devices. Sixteen patients (9.8%) required more than one ICP sensor due to malfunctioning of the system. In conclusion, continuous ICP monitoring using the Camino intraparenchymal sensor has a low complication rate. However, this sensor may underread the real ICP values in a high number of patients. The lack of correlation between duration of ICP monitoring and zero-drift suggests that, contrary to the recommendations of other reports, the intraparenchymatous Camino sensor can provide reliable readings after the fifth day of use.

A clinical evaluation of the Codman MicroSensor for intracranial pressure monitoring

The strain-gauge Codman MicroSensor intracranial pressure (ICP) transducer has shown consistently good laboratory performance. To assess the practical performance of the system in patients following acute brain injury, 10 patients were fitted with a MicroSensor and a second ICP monitor. In five cases this was a fibre-optic transducer and in five cases an intraventricular fluid-filled device. Paired ICP values were recorded every 5 min. ICP values ranged from 0 to 31 mmHg. Altman-Bland plots showed that individual readings could differ by as much as 9 mmHg. Further analysis showed that much of this disagreement could be explained by a constant offset on each occasion. Comparison traces of ICP in individual patients show high agreement in timing and size of changes. The unexplained constant offset leads to uncertainty about the true ICP. Treatment decisions are often based upon absolute levels of ICP and patient care may therefore differ depending upon the monitor used.

Intracranial Pressure Monitoring by Hydrostatic Pressure Balance Method

Intracranial pressure (ICP) measurement from the epidural space is desirable mainly because of its high protection against infections. The main problem, however, is how to exclude the effect of tension of the dura mater which makes the epidural pressure lower than ICP. The authors developed a hydrostatic pressure balance method, which keeps the nonelastic soft detector membrane contacting flat with the dura mater. The detector pouch is filled with saline of the proper volume and its pressure is transmitted to the pressure transducer through a slender tube. This pressure transmission through a tube realizes in principle an insensitive feature during the rotation of the patient's head, which otherwise causes a marked error from the true ICP. Over 60 clinical usages assure practical and infection-free features of this system. This system demonstrated high speed response and satisfactory accuracy. The pouch was easily inserted during craniotomy and extracted without any surgical procedures. It was also confirmed experimentally that this system is hardly affected by small particles or blood clots lying between the pouch and the dura mater. A comparison with conventional methods is discussed.

Accurate intracranial pressure monitoring

Intracranial pressure (ICP) monitoring may be misleading or inaccurate in patients who have sustained cerebral death or who have had cerebrospinal fluid drainage (e.g., due to skull fracture or craniotomy). ICP recording in these patients requires particular attention to the monitoring technique to avoid misleading values that may result in inappropriate therapy. We review methods for obtaining accurate ICP readings from fluid-interface systems using either a ventricular catheter or a subarachnoid screw. We suggest attention to the following: (a) elevation of the pressure in the external tubing and connections to ensure that there are no microleaks, (b) injection of a small volume of saline intracranially, and (c) awareness of what constitutes a true ICP reading. (Neurosurgery 14:592-593, 1984)

Accurate intracranial pressure monitoring: technical note.

Intracranial pressure (ICP) monitoring may be misleading or inaccurate in patients who have sustained cerebral death or who have had cerebrospinal fluid drainage (e.g., due to skull fracture or craniotomy). ICP recording in these patients requires particular attention to the monitoring technique to avoid misleading values that may result in inappropriate therapy. We review methods for obtaining accurate ICP readings from fluid-interface systems using either a ventricular catheter or a subarachnoid screw. We suggest attention to the following: (a) elevation of the pressure in the external tubing and connections to ensure that there are no microleaks , (b) injection of a small volume of saline intracranially, and (c) awareness of what constitutes a true ICP reading.

CONTINUOUS, DIRECT MEASUREMENT OF ICP BY A SUBARACHANOID BOLT IN ASPHXYIATED TERM NEONATES

A newly developed infant subarachnoid bolt was used to continuously and directly monitor intracranial pressure (ICP) in four severely asphyxiated (Apgars 11 and 25) full-term neonates. The plastic bolt was inserted through a dural puncture and secured to the margins of a right frontal bone craniotomy. No hemorrhage, CSF leak, infection or mechanical dislodgement occurred. The bolt was successfully used until the patients' death at postnatal ages 30, 42, 71 and 84 hours. Direct (bolt) ICP values were polygraphically recorded and correlated with simultaneous indirect (transfontanelle) ICP values, mean arterial blood pressure, clinical status and seizures confirmed by EEG. After the transfontanelle pressure transducer was applied with sufficient external tension to produce indirect ICP values that matched direct values, subsequent indirect ICP measurements correlated well from 4 to 13 torr (direct/indirect ratio: M = 1.07; range = 0.8 to 1.5). Indirect ICP measurements consistently and significantly underestimated true ICP from 14 to 35 torr (direct/indirect ratio; M = 2.3; range 2.1 to 3.2). Clinical neurological and/or EEG abnormalities preceded (by age 28 hrs) peak ICP (peak ICP = 18 torr) in all infants. A modest (4 torr) ICP elevation accompanied only 2 of 128 brief (duration = 39 sec; range = 12 to 180 sec), focal electrographic seizures. We conclude that direct ICP measurements by a subarachnoid bolt in appropriately selected, critically ill neonates can be safely achieved and may be more reliable than transfontanelle measurements.