A clinical comparison of subarachnoid catheters to ventriculostomy and subarachnoid bolts: a prospective study

Advances in Intracranial Pressure Monitoring and Its Significance in Managing Traumatic Brain Injury

Intracranial pressure (ICP) measurements are essential in evaluation and treatment of neurological disorders such as subarachnoid and intracerebral hemorrhage, ischemic stroke, hydrocephalus, meningitis/encephalitis, and traumatic brain injury (TBI). The techniques of ICP monitoring have evolved from invasive to non-invasive-with both limitations and advantages. Some limitations of the invasive methods include short-term monitoring, risk of infection, restricted mobility of the subject, etc. The invasiveness of a method limits the frequency of ICP evaluation in neurological conditions like hydrocephalus, thus hampering the long-term care of patients with compromised ICP. Thus, there has been substantial interest in developing noninvasive techniques for assessment of ICP. Several approaches were reported, although none seem to provide a complete solution due to inaccuracy. ICP measurements are fundamental for immediate care of TBI patients in the acute stages of severe TBI injury. In severe TBI, elevated ICP is associated with mortality or poor clinical outcome. ICP monitoring in conjunction with other neurological monitoring can aid in understanding the pathophysiology of brain damage. This review article presents: (a) the significance of ICP monitoring; (b) ICP monitoring methods (invasive and non-invasive); and (c) the role of ICP monitoring in the management of brain damage, especially TBI.

Recording of intracranial pressure in conscious rats via telemetry

Although cerebral perfusion pressure (CPP) is known to be fundamental in the control of normal brain function, there have been no previous long-term measurements in animal models. The aim of this study was to explore the stability and viability of long-term recordings of intracranial pressure (ICP) in freely moving rats via a telemetry device. We also developed a repeatable surgical approach with a solid-state pressure sensor at the tip of the catheter placed under the dura and in combination with arterial pressure (AP) measurement to enable the calculation of CPP. Telemeters with dual pressure catheters were implanted in Wistar rats to measure ICP and AP. We found that the signals were stable throughout the 28-day recording period with an average ICP value of 6 ± 0.8 mmHg. Significant light-dark differences were found in AP (3.1 ± 2.7 mmHg, P = 0.02) and HR (58 ± 12 beats/min, P = 0.003), but not ICP (0.3 ± 0.2 mmHg, P >0.05) or CPP (2.6 ± 2.8 mmHg, P > 0.05). Use of kaolin to induce hydrocephalus in several rats demonstrates the ability to measure changes in ICP throughout disease progression, validating this new solution for chronic measurement of ICP, CPP, and AP in conscious rats.

The complications and the position of the Codman MicroSensor™ ICP device: an analysis of 549 patients and 650 Sensors

BACKGROUND

Complications of and insertion depth of the Codman MicroSensor ICP monitoring device (CMS) is not well studied.

OBJECTIVE

To study complications and the insertion depth of the CMS in a clinical setting.

METHODS

We identified all patients who had their intracranial pressure (ICP) monitored using a CMS device between 2002 and 2010. The medical records and post implantation computed tomography (CT) scans were analyzed for occurrence of infection, hemorrhage and insertion depth.

RESULTS

In all, 549 patients were monitored using 650 CMS. Mean monitoring time was 7.0 ± 4.9 days. The mean implantation depth was 21.3 ± 11.1 mm (0-88 mm). In 27 of the patients, a haematoma was identified; 26 of these were less than 1 ml, and one was 8 ml. No clinically significant bleeding was found. There was no statistically significant increase in the number of hemorrhages in presumed coagulopathic patients. The infection rate was 0.6 % and the calculated infection rate per 1,000 catheter days was 0.8.

CONCLUSION

The risk for hemorrhagic and infectious complications when using the CMS for ICP monitoring is low. The depth of insertion varies considerably and should be taken into account if patients are treated with head elevation, since the pressure is measured at the tip of the sensor. To meet the need for ICP monitoring, an intraparenchymal ICP monitoring device should be preferred to the use of an external ventricular drainage (EVD).

Advances in ICP monitoring techniques

With the advent of newer devices for measuring intracranial pressure (ICP) and cerebral metabolism, more alternatives continue to rise aiming to control ICP. This manuscript presents a proposed analysis of different ICP monitoring devices in order to make appropriate selection of them in our clinical setting including general and pediatric applications. A systematic review of the literature was made analyzing the technical advances in ICP monitoring. The recent in vitro and in vivo tests as well as mathematical/computer models were reviewed. Practical applications of principles were discussed and compared based on the mode of pressure transformation. A ventricular catheter connected to an external strain gauge transducer or catheter tip pressure transducer device is considered to be the most accurate method of monitoring ICP and enables therapeutic CSF drainage. The significant infections or hemorrhage associated with ICP devices causing patients morbidity are clinically rare and should not deter the decision to monitor ICP. Parenchymal catheter tip pressure transducer devices are advantageous when ventricular ICP cannot be obtained or if there is an obstruction in the fluid couple, though they have the potential for significant measurement differences and drift due to the inability to recalibrate. Subarachnoid or subdural fluid-coupled devices and epidural ICP devices are currently less accurate. With an increasing miniaturization of the transducers, fiberoptic systems have been developed, however, there is a problem of measurement accuracy during the period of patient monitoring and external calibration should be performed frequently to ensure constant accuracy. Ventriculostomies continue to have a pivotal role in ICP control. With a rational understanding of the applications and limitations of the different ICP monitoring devices, the outcome for critically ill neurological patients is optimized.

Neurointensive care of the nonaccidentally injured child

Childhood victims of NAT with severe brain injury require a multidisciplinary approach to their management if a good outcome is to occur. Despite the grave prognosis of these patients, an initial aggressive treatment strategy is warranted, because enough children go on to a meaningful life. A vigilant evaluation for multisystem injuries and vigorous resuscitation should be followed by prompt surgical intervention as indicated. Most NAT victims do not require surgical treatment of their brain injury, but do require ICP monitoring. A stepwise approach to the treatment of elevated ICP optimizes CPP, minimizes secondary brain injury, and increases the chances of a meaningful recovery. The future holds promise for these patients because a concerted effort is underway to understand pediatric TBI on a molecular level, and targeted therapies based on current basic research will certainly improve the neurointensive care, and eventual neurologic outcomes, of these children.

[Technical aspects of intracranial pressure monitoring by subarachnoid method in severe head injury]

Two hundred and six patients with severe head injury (Glasgow Coma Scale of 8 points or less after nonsurgical resuscitation on admission), managed at Intensive Care Unit-Hospital das Clínicas - Universidade Estadual de Campinas were prospectively analysed. All patients were assessed by CT scan and 72 required neurosurgical intervention. All patients were continuously monitored to evaluate intracranial pressure (ICP) levels by a subarachnoid device (11 with subarachnoid metallic bolts and 195 with subarachnoid polyvinyl catheters). The ICP levels were continuously observed in the bedside pressure monitor display and their end-hour values were recorded in a standard chart. The patients were managed according to a standard protocol guided by the ICP levels. There were no intracranial haemorrhagic complications or hematomas due the monitoring method. Sixty six patients were punctured by lateral C1-C2 technique to assess infectious complications and 2 had positive cerebrospinal fluid samples for Acinetobacter sp. The final results measured at hospital discharge showed 75 deaths (36,40%) and 131 (63,60%) survivors. ICP levels had significantly influenced the final results (p<0,001). The subarachnoid method to continuously assess the ICP levels was considered applicable, safe, simple, low cost and useful to advise the management of the patients. The ICP record methodology was practical and useful. Despite the current technical advances the subarachnoid method was considered viable to assess the ICP levels in severe head injury.

Traumatic brain injury

The decrease in mortality and improved outcome for patients with severe traumatic brain injury over the past 25 years can be attributed to the approach of "squeezing oxygenated blood through a swollen brain". Quantification of cerebral perfusion by monitoring of intracranial pressure and treatment of cerebral hypoperfusion decrease secondary injury. Before the patient reaches hospital, an organised trauma system that allows rapid resuscitation and transport directly to an experienced trauma centre significantly lowers mortality and morbidity. Only the education of medical personnel and the institution of trauma hospital systems can achieve further improvements in outcome for patients with traumatic brain injuries.

Prophylactic antibiotics with intracranial pressure monitors and external ventricular drains: a review of the evidence

BACKGROUND

The role of prophylactic antibiotics (PABs) in preventing infections associated with intracranial pressure (ICP) monitors and external ventricular drains (EVD) is not well defined.

METHODS

This study includes an analysis of published reports and a survey of current practices regarding the use of PABs with ICP monitors and EVDs. A computerized data search and a review of the abstracts from two major national neurosurgical meetings over the past decade yielded 85 related articles. Three independent investigators, blinded to the title, author(s), institution(s), results, and conclusions of the articles used predetermined inclusion criteria to select studies for meta-analysis. Thirty-six responses were returned from 98 questionnaires (37%) mailed to university neurosurgical programs.

RESULTS

Among the articles reviewed, only two studies met the predetermined inclusion criteria for the meta-analysis, and they were of insufficient size to produce statistically significant results. Among the 36 programs that responded to the survey, 26 (72%) used PABs, mainly cephalosporins (46%) and semisynthetic penicillins (38%), with ICP monitors and EVDs. Twenty-two (85%) used one drug, and 4 (15%) used two drugs. Twenty-two (61%) of the total group reported intra-institutional variation in practices among individual staff neurosurgeons. Nineteen (53%) expressed interest in a retrospective study, and 27 (75%) expressed interest in a prospective study on the role of PABs in minor neurosurgical procedures.

CONCLUSION

No consensus regarding the use of PABs with ICP monitors and EVDs is noted. Randomized controlled trials of sufficiently large size with appropriate blinding are needed to address this issue.

Clinical evaluation of the InnerSpace fibreoptic intracranial pressure monitoring device

OBJECTIVE

The aim of this study is the clinical evaluation of the intraparenchymal ICP monitor InnerSpace OPX 100.

METHODS

Sixty-four Inner Space OPX 100 transducers in 51 patients with severe head injury (42), intracranial spontaneous bleeding (6) or hypoxia (3) were studied. The transducer was placed in the frontal white matter. Thirty-nine patients received one catheter, eleven patients two catheters and one patient three catheters. The study period ranged from 10 hours-25 days; total study time was 421.5 days (mean duration 6.6 days).

RESULTS

In nine cases (14.1%) an inadequate location of the ICP transducer was found, but the accuracy of the measurement was not influenced. Dislocation of the transducer occurred in eight cases (12.5%) due to inadequate handling. A failed transducer was observed in four cases (6.3%) because of a damaged optical fibre (1) or inadequate handling (3). In one patient (1.9%) a minor local infection developed. In eleven cases (17%) a haematoma around the ICP sensor was observed. Six haematomas were small; five haematomas were larger than 1 cm in diameter. In two patients a large frontal haematoma developed after exchange of the transducer. Operative evacuation was necessary in both cases. Zero shift was below 2 mmHg in all catheters.

CONCLUSION

It is concluded that the InnerSpace intraparenchymal ICP monitor is a reliable device: the rate of catheter related intracerebral haematomas, however, is not acceptable. This could be improved by a better fixation of the catheter in the burr hole in order to avoid micromovements of the transducer.

Bedside burr hole for intracranial pressure monitoring performed by intensive care physicians. A 5-year experience

OBJECTIVE

To assess the results of a 5-year experience with bedside burr hole for intracranial pressure (ICP) monitoring performed by intensive care physicians.

DESIGN

Prospective, observational study in 120 patients.

SETTING

A general-neurologic Intensive Care Unit in a University Hospital.

PATIENTS

Patients admitted for acute neural lesion requiring ICP monitoring.

METHOD

A 2.71 mm burr hole was made with positioning of a subarachnoid screw, through which a miniaturized fiberoptic, tip transducer device (Camino) was advanced and inserted 2 mm in the frontal cortex.

MAIN RESULTS

Over a 5-year period 120 patients, mainly with severe head trauma, underwent ICP monitoring. None of the planned patients was excluded because of technical difficulties. No life-threatening complications were reported, and the overall morbidity rate related to the ICP monitor was 3.3%. Complications were infectious in nature, with 2.5% wound infections and 0.8% meningitis. Although seven patients bled when opening the dura, no intracranial hematomas were recorded due to the ICP monitor. The fiberoptic device was left in place for 5 +/- 1.6 (SD) days (range 1-12 days). Five patients (4.1%) required catheter substitution due to breakage of the system components (fiberoptics).

CONCLUSIONS

Bedside insertion of a ICP monitor performed by intensive care physicians is a safe procedure, with a complication rate comparable to other series published by neurosurgeons. The overall morbidity rate is comparable to, or even lower than, that caused by central vein catheterization.

Highlighting intracranial pressure monitoring in patients with severe acute brain trauma

Intracranial pressure (ICP) monitoring was carried out in 100 patients with severe acute brain trauma, primarily by means of a subarachnoid catheter. Statistical associations were evaluated between maximum ICP values and: 1) Glasgow Coma Scale (GCS) scores; 2) findings on computed tomography (CT) scans of the head; and 3) mortality. A significant association was found between low GCS scores (3 to 5) and high ICP levels, as well as between focal lesions on CT scans and elevated ICP. Mortality was significantly higher in patients with ICP > 40 mm Hg than in those with ICP < or = 20 mm Hg.

Ventriculostomy and intracranial pressure monitoring: in search of a 0% infection rate

External ventriculostomy intracranial pressure (ICP) monitoring provides bedside practitioners with essential information about cranial dynamics as well as a means to maintain the balance within the cranium. Infection has been cited in the literature as the most common complication associated with ICP monitoring. This article reviews the research literature for the risk factors suggested to increase infection, presents data and practice guidelines from one institution where ICP monitors have been maintained infection free for more than 10 years, and summarizes the experiences of another institution where the 6-month infection rate of 55% associated with external ventriculostomy was reduced to 0% in the subsequent 6-month period. The actions taken by the multidisciplinary team to reduce the risk of infection are detailed. Recommendations for minimizing the risk of infection are made by the authors and are based on research studies and experience.

Relative risks of ventriculostomy infection and morbidity

Ventricular catheter placement is a common procedure for the management of increased intracranial pressure. Hypotheses regarding the etiology of infection of catheters center on two alternative assumptions: 1) contamination leading to infection occurs at the time of catheter insertion, implying that catheter duration has minimal effect on infection risk; and 2) infection of catheters derives from catheter contamination after insertion, suggesting that duration of catheter use may significantly affect infection risk. We have studied the relative complication rate of ventricular catheter insertions using a retrospective approach (n = 161 patients and 253 catheter insertion procedures). The overall infection rate was 4.1%, but the daily infection hazard increased exponentially with time, to a maximum daily rate of 10.3% by day 6 of catheter insertion. This increasing risk appears most consistent with the second hypothesis. The risk of non-infectious complications was 5.6%, including hemorrhagic occurrences and misplacement severe enough to require a new catheter insertion. The daily hazard of infection approximately equalled the non-infectious risk of routine catheter replacement by day 5. Additional prospective data on the daily risk of CSF infection and the appropriateness of antibiotic prophylaxis either at the time of ventricular catheter insertion or continued through the catheter's presence may be required to both definitively identify which hypothesis of infection risk is correct and whether antibiotics can significantly ameliorate this risk.

Clinical experience with a fiberoptic intracranial pressure monitor

Retrospective clinical experience with our first 46 patients monitored with a fiberoptic intracranial pressure device is described. In 43 of 46 patients, the transducer was introduced into brain parenchyma. A ventriculostomy system was used in 3 of 46 patients. The monitoring system was generally characterized by ease of placement and system maintenance and by technical simplicity. Several problems were encountered, including breakage of system components (12%), erroneous readings requiring transducer repositioning (8.6%), epidural hematoma (3.4%), and infection (1.7%). No infections or hematomas occurred in the 3 cases in which the ventriculostomy system was used. Overall, our experience with the Camino intracranial pressure fiberoptic monitoring system confirms previous reports of its favorable features.

Management of closed head injury in the patient with maxillofacial trauma

Closed head injury (CHI) affects approximately one in five patients who sustain facial fractures. The effects can range from simple loss of consciousness to coma and death. The high incidence of CHI in the facial trauma population and the potential for mortality and neurologic morbidity make it a distinct concern of the practicing oral and maxillofacial surgeon. This article discusses the evaluation, monitoring, and management of CHI and includes special consideration of the treatment of maxillofacial injuries in these patients.