A trial of intracranial-pressure monitoring in traumatic brain injury

Acute care clinical indicators associated with discharge outcomes in children with severe traumatic brain injury

OBJECTIVE

The effect of the 2003 severe pediatric traumatic brain injury (TBI) guidelines on outcomes has not been examined. We aimed to develop a set of acute care guideline-influenced clinical indicators of adherence and tested the relationship between these indicators during the first 72 hours after hospital admission and discharge outcomes.

DESIGN

Retrospective multicenter cohort study.

SETTING

Five regional pediatric trauma centers affiliated with academic medical centers.

PATIENTS

Children under 18 years with severe traumatic brain injury (admission Glasgow Coma Scale score ≤ 8, International Classification of Diseases, 9th Edition, diagnosis codes of 800.0-801.9, 803.0-804.9, 850.0-854.1, 959.01, 950.1-950.3, 995.55, maximum head abbreviated Injury Severity Score ≥ 3) who received tracheal intubation for at least 48 hours in the ICU between 2007 and 2011 were examined.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Total percent adherence to the clinical indicators across all treatment locations (prehospital, emergency department, operating room, and ICU) during the first 72 hours after admission to study center were determined. Main outcomes were discharge survival and Glasgow Outcome Scale score. Total adherence rate across all locations and all centers ranged from 68% to 78%. Clinical indicators of adherence were associated with survival (adjusted hazard ratios, 0.94; 95% CI, 0.91-0.96). Three indicators were associated with survival: absence of prehospital hypoxia (adjusted hazard ratios, 0.20; 95% CI, 0.08-0.46), early ICU start of nutrition (adjusted hazard ratios, 0.06; 95% CI, 0.01-0.26), and ICU PaCO2 more than 30 mm Hg in the absence of radiographic or clinical signs of cerebral herniation (adjusted hazard ratios, 0.22; 95% CI, 0.06-0.8). Clinical indicators of adherence were associated with favorable Glasgow Outcome Scale among survivors (adjusted hazard ratios, 0.99; 95% CI, 0.98-0.99). Three indicators were associated with favorable discharge Glasgow Outcome Scale: all operating room cerebral perfusion pressure more than 40 mm Hg (adjusted relative risk, 0.61; 95% CI, 0.58-0.64), all ICU cerebral perfusion pressure more than 40 mm Hg (adjusted relative risk, 0.73; 95% CI, 0.63-0.84), and no surgery (any type; adjusted relative risk, 0.68; 95% CI, 0.53- 0.86).

CONCLUSIONS

Acute care clinical indicators of adherence to the Pediatric Guidelines were associated with significantly higher discharge survival and improved discharge Glasgow Outcome Scale. Some indicators were protective, regardless of treatment location, suggesting the need for an interdisciplinary approach to the care of children with severe traumatic brain injury.

Effects of Intracranial Pressure Monitoring on Outcome of Patients with Severe Traumatic Brain Injury; Results of a Historical Cohort Study

OBJECTIVE

To investigate the effects of intracranial pressure (ICP) monitoring on mortality rate and functional outcome of patients with severe traumatic brain injury (TBI).

METHODS

This was historical cohort study being performed in Nemazee hospital of Shiraz during a 4-year period (from 2006 to 2010) including those patients with severe TBI who had undergone care based on ICP monitoring (case group) or clinical evaluation (control group).Patients and controls were matched regarding the age, sex, initial GCS, initial pupils, and CT findings. The functional outcome, complications and mortality rate were recorded and compared between those who underwent ICP monitoring and those who did not.

RESULTS

There was no significant difference between two study groups regarding the baseline characteristics. The rate of meningitis was significantly higher in those who underwent Ventriculostomy and ICP monitoring when compared to those who were managed without ICP monitoring. [14 (23.3%) vs. 7 (11.6%); p=0.041]. We found that the mortality rate (28.3% vs. 11.6%; p=0.172) as well as the frequency of persistent vegetative state (5.0% vs. 5.0%; p=0.998) were comparable between two study groups. However the frequency of severe disability was higher in control group compared to case group (26.7% vs. 15.0; p=0.046). In the same way, the frequency of good recovery (26.7% vs. 15.0; p=0.046) and favorable outcome (51.7% vs. 33.3%; p=0.021) was significantly higher in case group.

CONCLUSION

Care based on ICP monitoring in patients with severe TBI was associated with increased frequency of good recovery and favorable outcome and decreased frequency of moderate disability. However higher meningitis rate was associated with Ventriculostomy and ICP monitoring.

Critical care for patients with massive ischemic stroke

Malignant cerebral edema following ischemic stroke is life threatening, as it can cause inadequate blood flow and perfusion leading to irreversible tissue hypoxia and metabolic crisis. Increased intracranial pressure and brain shift can cause herniation syndrome and finally brain death. Multiple randomized clinical trials have shown that preemptive decompressive hemicraniectomy effectively reduces mortality and morbidity in patients with malignant middle cerebral artery infarction. Another life-saving decompressive surgery is suboccipital craniectomy for patients with brainstem compression by edematous cerebellar infarction. In addition to decompressive surgery, cerebrospinal fluid drainage by ventriculostomy should be considered for patients with acute hydrocephalus following stroke. Medical treatment begins with sedation, analgesia, and general measures including ventilatory support, head elevation, maintaining a neutral neck position, and avoiding conditions associated with intracranial hypertension. Optimization of cerebral perfusion pressure and reduction of intracranial pressure should always be pursued simultaneously. Osmotherapy with mannitol is the standard treatment for intracranial hypertension, but hypertonic saline is also an effective alternative. Therapeutic hypothermia may also be considered for treatment of brain edema and intracranial hypertension, but its neuroprotective effects have not been demonstrated in stroke. Barbiturate coma therapy has been used to reduce metabolic demand, but has become less popular because of its systemic adverse effects. Furthermore, general medical care is critical because of the complex interactions between the brain and other organ systems. Some challenging aspects of critical care, including ventilator support, sedation and analgesia, and performing neurological examinations in the setting of a minimal stimulation protocol, are addressed in this review.

Post-traumatic multimodal brain monitoring: response to hypertonic saline

Emerging evidence suggests that hypertonic saline (HTS) is efficient in decreasing intracranial pressure (ICP). However there is no consensus about its interaction with brain hemodynamics and oxygenation. In this study, we investigated brain response to HTS bolus with multimodal monitoring after severe traumatic brain injury (TBI). We included 18 consecutive TBI patients during 10 days after neurocritical care unit admission. Continuous brain monitoring applied included ICP, tissue oxygenation (PtO2) and cerebral blood flow (CBF). Cerebral perfusion pressure (CPP), cerebrovascular resistance (CVR), and reactivity indices related to pressure (PRx) and flow (CBFx) were calculated. ICM+software was used to collect and analyze monitoring data. Eleven of 18 (61%) patients developed 99 episodes of intracranial hypertension (IHT) greater than 20 mm Hg that were managed with 20% HTS bolus. Analysis over time was performed with linear mixed-effects regression modelling. After HTS bolus, ICP and CPP improved over time (p<0.001) following a quadratic model. From baseline to 120 min, ICP had a mean decrease of 6.2 mm Hg and CPP a mean increase of 3.1 mmHg. Mean increase in CBF was 7.8 mL/min/100 g (p<0.001) and mean decrease in CVR reached 0.4 mm Hg*min*100 g/mL (p=0.01). Both changes preceded pressures improvement. PtO2 exhibited a marginal increase and no significant models for time behaviour could be fitted. PRx and CBFx were best described by a linear decreasing model showing autoregulation recover after HTS (p=0.01 and p=0.04 respectively). During evaluation, CO2 remained constant and sodium level did not exhibit significant variation. In conclusion, management of IHT with 20% HTS significantly improves cerebral hemodynamics and cerebrovascular reactivity with recovery of CBF appearing before rise in CPP and decrease in ICP. In spite of cerebral hemodynamic improvement, no significant changes in brain oxygenation were identified.

Neurotrauma

Neurotrauma continues to be a significant cause of morbidity and mortality. Prevention of primary neurologic injury is a critical public health concern. Early and thorough assessment of the patient with neurotrauma with high index of suspicion of traumatic spinal cord injuries and traumatic vascular injuries requires a multidisciplinary approach involving prehospital providers, emergency physicians, neurosurgeons, and neurointensivists. Critical care management of the patient with neurotrauma is focused on the prevention of secondary injuries. Much research is still needed for potential neuroprotection therapies.

Current concepts of optimal cerebral perfusion pressure in traumatic brain injury

Traumatic brain injury (TBI) consists of varied pathophysiological consequences and alteration of intracranial dynamics, reduction of the cerebral blood flow and oxygenation. In the past decade more emphasis has been directed towards optimizing cerebral perfusion pressure (CPP) in patients who have suffered TBI. Injured brain may show signs of ischemia if CPP remains below 50 mmHg and raising the CPP above 60 mmHg may avoid cerebral oxygen desaturation. Though CPP above 70 mmHg is influential in achieving an improved patient outcome, maintenance of CPP higher than 70 mmHg was associated with greater risk of acute respiratory distress syndrome (ARDS). The target CPP has been laid within 50-70 mmHg. Cerebral blood flow and metabolism are heterogeneous after TBI and with regional temporal differences in the requirement for CPP. Brain monitoring techniques such as jugular venous oximetry, monitoring of brain tissue oxygen tension (PbrO₂), and cerebral microdialysis provide complementary and specific information that permits the selection of the optimal CPP. This review highlights the rationale for use CPP directed therapies and neuromonitoring to identify optimal CPP of head injured patients. The article also reviews the evidence provided by various clinical trials regarding optimal CPP and their application in the management of head injured patients.

Consensus summary statement of the International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care : a statement for healthcare professionals from the Neurocritical Care Society and the European Society of Intensive Care Medicine

Neurocritical care depends, in part, on careful patient monitoring but as yet there are little data on what processes are the most important to monitor, how these should be monitored, and whether monitoring these processes is cost-effective and impacts outcome. At the same time, bioinformatics is a rapidly emerging field in critical care but as yet there is little agreement or standardization on what information is important and how it should be displayed and analyzed. The Neurocritical Care Society in collaboration with the European Society of Intensive Care Medicine, the Society for Critical Care Medicine, and the Latin America Brain Injury Consortium organized an international, multidisciplinary consensus conference to begin to address these needs. International experts from neurosurgery, neurocritical care, neurology, critical care, neuroanesthesiology, nursing, pharmacy, and informatics were recruited on the basis of their research, publication record, and expertise. They undertook a systematic literature review to develop recommendations about specific topics on physiologic processes important to the care of patients with disorders that require neurocritical care. This review does not make recommendations about treatment, imaging, and intraoperative monitoring. A multidisciplinary jury, selected for their expertise in clinical investigation and development of practice guidelines, guided this process. The GRADE system was used to develop recommendations based on literature review, discussion, integrating the literature with the participants' collective experience, and critical review by an impartial jury. Emphasis was placed on the principle that recommendations should be based on both data quality and on trade-offs and translation into clinical practice. Strong consideration was given to providing pragmatic guidance and recommendations for bedside neuromonitoring, even in the absence of high quality data.

Clinical applications of intracranial pressure monitoring in traumatic brain injury : report of the Milan consensus conference

BACKGROUND

Intracranial pressure (ICP) monitoring has been for decades a cornerstone of traumatic brain injury (TBI) management. Nevertheless, in recent years, its usefulness has been questioned in several reports. A group of neurosurgeons and neurointensivists met to openly discuss, and provide consensus on, practical applications of ICP in severe adult TBI.

METHODS

A consensus conference was held in Milan on October 5, 2013, putting together neurosurgeons and intensivists with recognized expertise in treatment of TBI. Four topics have been selected and addressed in pro-con presentations: 1) ICP indications in diffuse brain injury, 2) cerebral contusions, 3) secondary decompressive craniectomy (DC), and 4) after evacuation of intracranial traumatic hematomas. The participants were asked to elaborate on the existing published evidence (without a systematic review) and their personal clinical experience. Based on the presentations and discussions of the conference, some drafts were circulated among the attendants. After remarks and further contributions were collected, a final document was approved by the participants. The group made the following recommendations: 1) in comatose TBI patients, in case of normal computed tomography (CT) scan, there is no indication for ICP monitoring; 2) ICP monitoring is indicated in comatose TBI patients with cerebral contusions in whom the interruption of sedation to check neurological status is dangerous and when the clinical examination is not completely reliable. The probe should be positioned on the side of the larger contusion; 3) ICP monitoring is generally recommended following a secondary DC in order to assess the effectiveness of DC in terms of ICP control and guide further therapy; 4) ICP monitoring after evacuation of an acute supratentorial intracranial hematoma should be considered for salvageable patients at increased risk of intracranial hypertension with particular perioperative features.

The effect of baseline pressure errors on an intracranial pressure-derived index: results of a prospective observational study

Background

In order to characterize the intracranial pressure-volume reserve capacity, the correlation coefficient (R) between the ICP wave amplitude (A) and the mean ICP level (P), the RAP index, has been used to improve the diagnostic value of ICP monitoring. Baseline pressure errors (BPEs), caused by spontaneous shifts or drifts in baseline pressure, cause erroneous readings of mean ICP. Consequently, BPEs could also affect ICP indices such as the RAP where in the mean ICP is incorporated.

Methods

A prospective, observational study was carried out on patients with aneurysmal subarachnoid hemorrhage (aSAH) undergoing ICP monitoring as part of their surveillance. Via the same burr hole in the scull, two separate ICP sensors were placed close to each other. For each consecutive 6-sec time window, the dynamic mean ICP wave amplitude (MWA; measure of the amplitude of the single pressure waves) and the static mean ICP, were computed. The RAP index was computed as the Pearson correlation coefficient between the MWA and the mean ICP for 40 6-sec time windows, i.e. every subsequent 4-min period (method 1). We compared this approach with a method of calculating RAP using a 4-min moving window updated every 6 seconds (method 2).

Results

The study included 16 aSAH patients. We compared 43,653 4-min RAP observations of signals 1 and 2 (method 1), and 1,727,000 6-sec RAP observations (method 2). The two methods of calculating RAP produced similar results. Differences in RAP ≥0.4 in at least 7% of observations were seen in 5/16 (31%) patients. Moreover, the combination of a RAP of ≥0.6 in one signal and <0.6 in the other was seen in ≥13% of RAP-observations in 4/16 (25%) patients, and in ≥8% in another 4/16 (25%) patients. The frequency of differences in RAP >0.2 was significantly associated with the frequency of BPEs (5 mmHg ≤ BPE <10 mmHg).

Conclusions

Simultaneous monitoring from two separate, close-by ICP sensors reveals significant differences in RAP that correspond to the occurrence of BPEs. As differences in RAP are of magnitudes that may alter patient management, we do not advocate the use of RAP in the management of neurosurgical patients.

What is wrong with the tenets underpinning current management of severe traumatic brain injury?

The results of a recent randomized controlled trial comparing intracranial pressure (ICP) monitor-based treatment of severe traumatic brain injury (sTBI) to management without ICP monitoring prompt this skeptical reconsideration of the scientific foundation underlying current sTBI management. Much of current practice arises from research performed under conditions that are no longer relevant today. The definition of an episode of intracranial hypertension is incomplete, and the application of a fixed, universal ICP treatment threshold is poorly founded. Although intracranial hypertension is a valid indicator of disease severity, it remains to be demonstrated that lowering ICP improves outcome. Furthermore, sTBI has not been categorized on the basis of underlying pathophysiology despite the current capability to do so. Similar concerns also apply to manipulation of cerebral perfusion with respect to maintaining universal thresholds for contrived variables rather than tailoring treatment to monitored processes. As such, there is a failure to either optimize management approaches or minimize associated treatment risks for individual sTBI patients. The clinical and research TBI communities need to reassess many of the sTBI management concepts that are currently considered well established.

Monitoring of intracranial pressure in patients with traumatic brain injury

Since Monro published his observations on the nature of the contents of the intracranial space in 1783, there has been investigation of the unique relationship between the contents of the skull and the intracranial pressure (ICP). This is particularly true following traumatic brain injury (TBI), where it is clear that elevated ICP due to the underlying pathological processes is associated with a poorer clinical outcome. Consequently, there is considerable interest in monitoring and manipulating ICP in patients with TBI. The two techniques most commonly used in clinical practice to monitor ICP are via an intraventricular or intraparenchymal catheter with a microtransducer system. Both of these techniques are invasive and are thus associated with complications such as hemorrhage and infection. For this reason, significant research effort has been directed toward development of a non-invasive method to measure ICP. The principle aims of ICP monitoring in TBI are to allow early detection of secondary hemorrhage and to guide therapies that limit intracranial hypertension (ICH) and optimize cerebral perfusion. However, information from the ICP value and the ICP waveform can also be used to assess the intracranial volume-pressure relationship, estimate cerebrovascular pressure reactivity, and attempt to forecast future episodes of ICH.

A conceptual approach to managing severe traumatic brain injury in a time of uncertainty

Current controversies in the literature suggest that a reassessment of the current management of severe traumatic brain injury (sTBI) is necessary. This article presents a conceptual framework toward individualizing sTBI treatment with respect to targeting thresholds and strategies on the basis of known physiologic processes and available monitors. Intracranial pressure (ICP) is modeled as an epiphenomenon of cerebral compliance and herniation tendency, as well as cerebral ischemia. By combining serial neurological examinations, imaging studies, and ICP measurements (values, trends, and area-under-the-curve calculations) over time, evidence can be accrued on the necessity of maintaining ICP at a given threshold in the realm of physical changes in the brain. Similarly, by collecting and trending clinical, imaging, and monitoring data on the status of cerebral blood flow, the balance of oxygen consumption and delivery, and the status of cerebral static pressure autoregulation, and analyzing them with respect to measured parameters, such as blood pressure, ICP, and cerebral perfusion pressure, one can attempt to fine-tune these variables as well. Such individualization of management optimizes the possibility of successfully treating demonstrated pathophysiological processes while avoiding unnecessary interventions and treatment toxicity. Monitor values must not be seen as targets but rather as indicators of targetable pathology.

National variability in intracranial pressure monitoring and craniotomy for children with moderate to severe traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of mortality and disability in children. Intracranial pressure monitoring (ICPM) and craniotomy/craniectomy (CRANI) may affect outcomes. Sources of variability in the use of these interventions remain incompletely understood.

OBJECTIVE

To analyze sources of variability in the use of ICPM and CRANI.

METHODS

Retrospective cross-sectional study of patients with moderate/severe pediatric TBI with the use of data submitted to the American College of Surgeons National Trauma Databank.

RESULTS

We analyzed data from 7140 children at 156 US hospitals during 7 continuous years. Of the children, 27.4% had ICPM, whereas 11.7% had a CRANI. Infants had lower rates of ICPM and CRANI than older children. A lower rate of ICPM was observed among children hospitalized at combined pediatric/adult trauma centers than among children treated at adult-only trauma centers (relative risk = 0.80; 95% confidence interval 0.66-0.97). For ICPM and CRANI, 18.5% and 11.6%, respectively, of residual model variance was explained by between-hospital variation in care delivery, but almost no correlation was observed between within-hospital tendency toward performing these procedures.

CONCLUSION

Infants received less ICPM than older children, and children hospitalized at pediatric trauma centers received less ICPM than children at adult-only trauma centers. In addition, significant between-hospital variability existed in the delivery of ICPM and CRANI to children with moderate-severe TBI.

Management of hepatic encephalopathy

OPINION STATEMENT

Hepatic encephalopathy management varies depending on the acuity of liver failure. However, in patients with either acute or chronic liver failure five basic steps in management are critical: stabilization, addressing modifiable precipitating factors, lowering blood ammonia, managing elevated intracranial pressure (ICP) (if present), and managing complications of liver failure that can contribute to encephalopathy, particularly hyponatremia. Because liver failure patients are prone to a variety of other medical problems that can lead to encephalopathy (such as coagulopathy associated intracranial hemorrhage, electrolyte disarray, renal failure, hypotension, hypoglycemia, and infection), a thorough history, physical and neurologic examination is mandated in all encephalopathic liver failure patients. There should be a low threshold for brain imaging in patients with focal neurological deficits given the propensity for spontaneous intracranial hemorrhage. In patients with acute liver failure and high grade encephalopathy, identification of the etiology of acute liver failure is essential to guide treatment and antidote administration, particularly in the case of acetaminophen poisoning. Equally critical is management of elevated ICP in acute liver failure. Intracranial hypertension can be treated with hypertonic saline and/or adjustment of the dialysis bath. Placement of an intracranial monitor to guide ICP therapy is risky because of concomitant coagulopathy and remains controversial. Continuous renal replacement therapy may help lower serum ammonia, treat coexisting uremia, and improve symptoms. Liver transplantation is the definitive treatment for patients with acute liver failure and hepatic encephalopathy. In patients with chronic hepatic encephalopathy, lactulose and rifaxamin remain a mainstay of therapy. In these patients, it is essential to identify reversible causes of hepatic encephalopathy such as increased ammonia production and/or decreased clearance (eg, infection, GI bleed, constipation, hypokalemia, dehydration). Chronic hyponatremia should be managed by gradual sodium correction of no more than 8‒12 meq/L per day to avoid central myelinolysis syndrome. Free water restriction and increased dietary sodium are reasonable, cost effective treatment options. Many emerging therapies, both pharmacologic and interventional, are currently being studied to improve management of hepatic encephalopathy.

Decompressive craniectomy for management of traumatic brain injury: an update

Decompressive craniectomy (DC) for the management of severe traumatic brain injury (TBI) has a long history but remains controversial. Although DC has been shown to improve both survival and functional outcome in patients with malignant cerebral infarctions, evidence of benefit in patients with TBI is decidedly more mixed. Craniectomy can clearly be life-saving in the presence of medically intractable elevations of intracranial pressure. Craniectomy also has been consistently demonstrated to reduce "therapeutic intensity" in the ICU, to reduce the need for intracranial-pressure-directed and brain-oxygen-directed interventions, and to reduce ICU length of stay. Still, the only randomized trial of DC in TBI failed to demonstrate any benefit. Studies of therapies for TBI, including hemicraniectomy, are challenging owing to the inherent heterogeneity in the pathophysiology observed in this disease. Craniectomy can be life-saving for patients with severe TBI, but many questions remain regarding its ideal application, and the outcome remains highly correlated with the severity of the initial injury.

Pressure autoregulation monitoring and cerebral perfusion pressure target recommendation in patients with severe traumatic brain injury based on minute-by-minute monitoring data

OBJECT

In severe traumatic brain injury, a universal target for cerebral perfusion pressure (CPP) has been abandoned. Attempts to identify a dynamic CPP target based on the patient's cerebrovascular autoregulatory capacity have been promising so far. Bedside monitoring of pressure autoregulatory capacity has become possible by a number of methods, Czosnyka's pressure reactivity index (PRx) being the most frequently used. The PRx is calculated as the moving correlation coefficient between 40 consecutive 5-second averages of intracranial pressure (ICP) and mean arterial blood pressure (MABP) values. Plotting PRx against CPP produces a U-shaped curve in roughly two-thirds of monitoring time, with the bottom of this curve representing a CPP range corresponding with optimal autoregulatory capacity (CPPopt). In retrospective series, keeping CPP close to CPPopt corresponded with better outcomes. Monitoring of PRx requires high-frequency signal processing. The aim of the present study is to investigate how the processing of the information on cerebrovascular pressure reactivity that can be obtained from routine minute-by-minute ICP and MABP data can be enhanced to enable CPPopt recommendations that do not differ from those obtained by the PRx method, show the same associations with outcome, and can be generated in more than two-thirds of monitoring time.

METHODS

The low-frequency autoregulation index (LAx) was defined as the moving minute-by-minute ICP/MABP correlation coefficient calculated over time intervals varying from 3 to 120 minutes. The CPPopt calculation was based on LAx-CPP plots and done for time windows between 1 and 24 hours and for each LAx type. The resulting matrix of CPPopts were then averaged in a weighted manner, with the weight based on the goodness of fit of a U-shape and the lower value of the LAx corresponding to the U-bottom, to result in a final CPPopt recommendation. The association between actual CPP/CPPopt and outcome was assessed in the multicenter Brain Monitoring with Information Technology Research Group (BrainIT) database (n = 180). In the Leuven-Tübingen database (60-Hz waveform data, n = 21), LAx- and PRx-based CPPopts were compared.

RESULTS

In the BrainIT database, CPPopt recommendations were generated in 95% of monitoring time. Actual CPP being close to LAx-based CPPopt was associated with increased survival. In a multivariate model using the Corticosteroid Randomization After Significant Head Injury (CRASH) model as covariates, the average absolute difference between actual CPP and CPPopt was independently associated with increased mortality. In the high-frequency data set no significant difference was observed between PRx-based and LAx-based CPPopts. The new method issued a CPPopt recommendation in 97% of monitoring time, as opposed to 44% for PRx-based CPPopt.

CONCLUSIONS

Minute-by-minute ICP/MABP data contain relevant information for autoregulation monitoring. In this study, the authors' new method based on minute-by-minute data resolution allowed for CPPopt calculation in nearly the entire monitoring time. This will facilitate the use of pressure reactivity monitoring in all ICUs.

Successful placement of intracranial pressure monitors by trauma surgeons

BACKGROUND

The Brain Trauma Foundation guidelines advocate for the use of intracranial pressure (ICP) monitoring following traumatic brain injury (TBI) in patients with a Glasgow Coma Scale (GCS) score of 8 or less and an abnormal computed tomographic scan finding. The absence of 24-hour in-house neurosurgery coverage can negatively impact timely monitor placement. We reviewed the safety profile of ICP monitor placement by trauma surgeons trained and credentialed in their insertion by neurosurgeons.

METHODS

In 2005, the in-house trauma surgeons at a Level I trauma center were trained and credentialed in the placement of ICP parenchymal monitors by the neurosurgeons. We abstracted all TBI patients who had ICP monitors placed during a 6-year period. Demographic information, Injury Severity Score (ISS), outcome, and monitor placement by neurosurgery or trauma surgery were identified. Misplacement, hemorrhage, infections, malfunctions, and dislodgement were considered complications. Comparisons were performed by χ testing and Student's t tests.

RESULTS

During the 6-year period, 410 ICP monitors were placed for TBI. The mean (SD) patient age was 40.9 (18.9) years, 73.7% were male, mean (SD) ISS was 28.3 (9.4), mean (SD) length of stay was 19 (16) days, and mortality was 36.1%. Motor vehicle collisions and falls were the most common mechanisms of injury (35.2% and 28.7%, respectively). The trauma surgeons placed 71.7 % of the ICP monitors and neurosurgeons for the remainder. The neurosurgeons placed most of their ICP monitors (71.8%) in the operating room during craniotomy. The overall complication rate was 2.4%. There was no significant difference in complications between the trauma surgeons and neurosurgeons (3% vs. 0.8%, p = 0.2951).

CONCLUSION

After appropriate training, ICP monitors can be safely placed by trauma surgeons with minimal adverse effects. With current and expected specialty shortages, acute care surgeons can successfully adopt procedures such as ICP monitor placement with minimal complications.

LEVEL OF EVIDENCE

Therapeutic/care management study, level IV.

Evidence-based neurocritical care

Neurocritical care is a pioneering subspecialty dedicated to the treatment of patients with life-threatening neurological illnesses, postoperative neurosurgical complications, and neurological manifestations of systemic disease. The care of these patients requires specialized neurological monitoring and specific clinical expertise and has generated a body of literature commensurate with the expansion of the field. This article reviews landmark studies over the last 10 years in the management and treatment of common acute neurological illnesses including massive cerebral infarction, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and status epilepticus.

Patient-specific thresholds of intracranial pressure in severe traumatic brain injury

Object

Based on continuous monitoring of the pressure reactivity index (PRx), the authors defined individualized intracranial pressure (ICP) thresholds by graphing the relationship between ICP and PRx. These investigators hypothesized that an “ICP dose” based on individually assessed ICP thresholds would correlate more closely with the 6-month outcome when compared with ICP doses derived by the recommended universal thresholds of 20 and 25 mm Hg.

Methods

This study was a retrospective analysis of prospectively collected data from 327 patients with severe traumatic brain injury.

Results

Individualized thresholds were visually identified from graphs of PRx versus ICP; PRx > 0.2 was the cutoff. Intracranial pressure doses were then computed as the cumulative area under the curve above the defined thresholds in graphing ICP versus time. The term “Dose 20” (D20) was used to refer to an ICP threshold of 20 mm Hg; the markers D25 and DPRx were calculated similarly. Separate logistic regression models were fit with death as the outcome and each dose as the predictor, both alone and adjusted for covariates. The discriminative ability of each dose for mortality was assessed by receiver operating characteristic AUC analysis in which 5-fold cross-validation was used. A clearly identifiable PRx-based threshold was possible in 224 patients (68%). The DPRx (AUC 0.81, 95% CI 0.74–0.87) was found to have the highest area under the curve (AUC) over both D20 (0.75, 95% CI 0.68–0.81) and D25 (0.77, 95% CI 0.70–0.83); in the cross-validation model, DPRx remained the best discriminator of mortality (DPRx: AUC 0.77 [95% CI 0.68–0.89]; D20: 0.72 [95% CI 0.66–0.81]; and D25: 0.65 [95% CI 0.56–0.73]).

Conclusions

The authors explored the importance of different ICP thresholds for outcome by calculating patient-specific ICP doses based on the continuous monitoring of cerebrovascular pressure reactivity. They found that these individualized doses of intracranial hypertension were stronger predictors of death than doses derived from the universal thresholds of 20 and 25 mm Hg. The PRx could offer a method that can be directed toward individualizing the ICP threshold.

Specific intensive care management of patients with traumatic brain injury: Present and future

Traumatic brain injury (TBI) is a major global problem and affects approximately 10 million peoples annually; therefore has a substantial impact on the health-care system throughout the world. In this article, we have summarized various aspects of specific intensive care management in patients with TBI including the emerging evidence mainly after the Brain Trauma Foundation (BTF) 2007 and also highlighted the scope of the future therapies. This review has involved the relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic. Though, BTF guideline based management strategies could provide standardized protocols for the management of patients with TBI and have some promising effects on mortality and morbidity; there is still need of inclusion of many suggestions based on various published after 2007. The main focus of majority of these trials remained to prevent or to treat the secondary brain injury. The future therapy will be directed to treat injured neurons and may benefit the outcome. There is also urgent need to develop some good prognostic indicators as well.

[Intracranial pressure monitoring in severe traumatic brain injury: A different perspective of the BestTrip trial]

The present study outlines a series of questions and reflections upon the recent publication of Chesnut et al., who compared 2 approaches to the treatment of intracranial hypertension (ICH) in severe head injuries: one with and the other without intracranial pressure monitoring (ICP). The authors concluded that no improved outcome was observed in the treatment group guided by ICP monitoring. The main concerns relate to the degree of training of the physicians involved in the monitoring and management of ICH in the ICP group, as well as to the possible inter-observer variability in interpreting the CT scans, the capacity of clinical signs to guide the treatment of ICH, and the suitability of randomization. The analysis of this trial should not be taken to suggest the futility of ICP monitoring but rather the need to correctly use the information afforded by ICP monitoring, with emphasis on the importance of the definition of alternative methods for non-invasive monitoring.

Optimal cerebral perfusion pressure in patients with intracerebral hemorrhage: an observational case series

Introduction

Current guidelines for spontaneous intracerebral hemorrhage (ICH) recommend maintaining cerebral perfusion pressure (CPP) between 50 and 70 mmHg, depending on the state of autoregulation. We continuously assessed dynamic cerebral autoregulation and the possibility of determination of an optimal CPP (CPPopt) in ICH patients. Associations between autoregulation, CPPopt and functional outcome were explored.

Methods

Intracranial pressure (ICP), mean arterial pressure (MAP) and CPP were continuously recorded in 55 patients, with 38 patients included in the analysis. The pressure reactivity index (PRx) was calculated as moving correlation between MAP and ICP. CPPopt was defined as the CPP associated with the lowest PRx values. CPPopt was calculated using hourly updated of 4 hour windows. The modified Rankin Scale (mRS) was assessed at 3 months and associations between PRx, CPPopt and outcomes were explored using Pearson correlation and Fisher’s exact test. Multivariate stepwise logistic regression models were calculated including standard outcome predictors along with percentage of time with PRx >0.2 and percentage of time within the CPPopt range.

Results

An overall PRx indicating impairment of pressure reactivity was found in 47% of patients (n = 18). The mean PRx and the time spent with a PRx > 0.2 significantly correlated with mRS at 3 months (r = 0.50, P = 0.002; r = 0.46, P = 0.004). CPPopt was calculable during 57% of the monitoring time. The median CPP was 78 mmHg, the median CPPopt 83 mmHg. Mortality was lowest in the group of patients with a CPP close to their CPPopt. However, for none of the CPPopt variables a significant association to outcome was found. The percentage of time with impaired autoregulation and hemorrhage volume were independent predictors for acceptable outcome (mRS 1 to 4) at three months.

Conclusions

Failure of pressure reactivity seems common following severe ICH and is associated with unfavorable outcome. Real-time assessment of CPPopt is feasible in ICH and might provide a tool for an autoregulation-oriented CPP management. A larger trial is needed to explore if a CPPopt management results in better functional outcomes.

Monitoring of acute traumatic brain injury in adults to prevent secondary brain damage

ABSTRACT: Traumatic brain injury is typically characterized by the primary injury initiating a cascade of pathologic changes that then lead to secondary brain injury. Secondary brain injury is amenable to different therapeutic options. Monitoring of otherwise occult pathologic changes involving oxygenation and metabolism is crucial for treatment decisions. Currently, decision-making is mainly based on measuring intracranial pressure and cerebral perfusion pressure. Importantly, extending neuromonitoring by including parameters reflecting cerebral perfusion, oxygenation and metabolism may improve treatment of traumatic brain injury patients by detecting neuronal damage despite optimal intracranial pressure or cerebral perfusion pressure and preventing unnecessarily aggressive treatment potentially causing local and systemic harm. In this review, the authors describe the advantages and disadvantages of contemporary, extended neuromonitoring methods in traumatic brain injury patients aimed at unmasking secondary brain damage as early as possible.

Routine follow-up cranial computed tomography for deeply sedated, intubated, and ventilated multiple trauma patients with suspected severe head injury

Background. Missed or delayed detection of progressive neuronal damage after traumatic brain injury (TBI) may have negative impact on the outcome. We investigated whether routine follow-up CT is beneficial in sedated and mechanically ventilated trauma patients. Methods. The study design is a retrospective chart review. A routine follow-up cCT was performed 6 hours after the admission scan. We defined 2 groups of patients, group I: patients with equal or recurrent pathologies and group II: patients with new findings or progression of known pathologies. Results. A progression of intracranial injury was found in 63 patients (42%) and 18 patients (12%) had new findings in cCT 2 (group II). In group II a change in therapy was found in 44 out of 81 patients (54%). 55 patients with progression or new findings on the second cCT had no clinical signs of neurological deterioration. Of those 24 patients (44%) had therapeutic consequences due to the results of the follow-up cCT. Conclusion. We found new diagnosis or progression of intracranial pathology in 54% of the patients. In 54% of patients with new findings and progression of pathology, therapy was changed due to the results of follow-up cCT. In trauma patients who are sedated and ventilated for different reasons a routine follow-up CT is beneficial.

The effects of intracranial pressure monitoring in patients with traumatic brain injury

Background

Although international guideline recommended routine intracranial pressure (ICP) monitoring for patients with severe traumatic brain injury(TBI), there were conflicting outcomes attributable to ICP monitoring according to the published studies. Hence, we conducted a meta-analysis to evaluate the efficacy and safety of ICP monitoring in patients with TBI.

Methods

Based on previous reviews, PubMed and two Chinese databases (Wangfang and VIP) were further searched to identify eligible studies. The primary outcome was mortality. Secondary outcomes included unfavourable outcome, adverse events, length of ICU stay and length of hospital stay. Weighted mean difference (WMD), odds ratio (OR) and 95% confidence intervals (CIs) were calculated and pooled using fixed-effects or random-effects model.

Results

two randomized controlled trials (RCTs) and seven cohort studies involving 11,038 patients met the inclusion criteria. ICP monitoring was not associated with a significant reduction in mortality (OR, 1.16; 95% CI, 0.87–1.54), with substantial heterogeneity (I² = 80%, P<0.00001), which was verified by the sensitivity analyses. No significant difference was found in the occurrence of unfavourable outcome (OR, 1.40; 95% CI, 0.99–1.98; I² = 4%, P = 0.35) and advese events (OR, 1.04; 95% CI, 0.64–1.70; I² = 78%, P = 0.03). However, we should be cautious to the result of adverse events because of the substantial heterogeneity in the comparison. Furthermore, longer ICU and hospital stay were the consistent tendency according to the pooled studies.

Conclusions

No benefit was found in patients with TBI who underwent ICP monitoring. Considering substantial clinical heterogeneity, further large sample size RCTs are needed to confirm the current findings.

Patients with brain contusions: predictors of outcome and relationship between radiological and clinical evolution

OBJECT

Traumatic parenchymal mass lesions are common sequelae of traumatic brain injuries (TBIs). They occur in up to 8.2% of all TBI cases and 13%-35% of severe TBI cases, and they account for up to 20% of surgical intracranial lesions. Controversy exists concerning the association between radiological and clinical evolution of brain contusions. The aim of this study was to identify predictors of unfavorable outcome, analyze the evolution of brain contusions, and evaluate specific indications for surgery.

METHODS

In a retrospective, multicenter study, patients with brain contusions were identified in separate patient cohorts from 11 hospitals over a 4-year period (2008-2011). Data on clinical parameters and course of the contusion were collected. Radiological parameters were registered by using CT images taken at the time of hospital admission and at subsequent follow-up times. Patients who underwent surgical procedures were identified. Outcomes were evaluated 6 months after trauma by using the Glasgow Outcome Scale-Extended.

RESULTS

Multivariate analysis revealed the following reliable predictors of unfavorable outcome: 1) increased patient age, 2) lower Glasgow Coma Scale score at first evaluation, 3) clinical deterioration in the first hours after trauma, and 4) onset or increase of midline shift on follow-up CT images. Further multivariate analysis identified the following as statistically significant predictors of clinical deterioration during the first hours after trauma: 1) onset of or increase in midline shift on follow-up CT images (p < 0.001) and 2) increased effacement of basal cisterns on follow-up CT images (p < 0.001).

CONCLUSIONS

In TBI patients with cerebral contusion, the onset of clinical deterioration is predictably associated with the onset or increase of midline shift and worsened status of basal cisterns but not with hematoma or edema volume increase. A combination of clinical deterioration and increased midline shift/basal cistern compression is the most reasonable indicator for surgery.

Management of raised intracranial pressure and hyperosmolar therapy

The management of raised intracranial pressure is undergoing rapid change. The choice of medical treatments to reduce intracranial pressure varies between institutions and regions of the world. The mainstay of therapy, however, continues to be the infusion of a hyperosmolar solution to achieve an osmotic gradient to force the exit of water from the brain. This review introduces the basic concepts of raised intracranial pressure, summarises several recent studies that have challenged dogma in the field, and provides practical advice on hyperosmolar treatment, based on personal experience and a critical reading of the literature.

Baseline pressure errors (BPEs) extensively influence intracranial pressure scores: results of a prospective observational study

Background

Monitoring of intracranial pressure (ICP) is a cornerstone in the surveillance of neurosurgical patients. The ICP is measured against a baseline pressure (i.e. zero - or reference pressure). We have previously reported that baseline pressure errors (BPEs), manifested as spontaneous shift or drifts in baseline pressure, cause erroneous readings of mean ICP in individual patients. The objective of this study was to monitor the frequency and severity of BPEs. To this end, we performed a prospective, observational study monitoring the ICP from two separate ICP sensors (Sensors 1 and 2) placed in close proximity in the brain. We characterized BPEs as differences in mean ICP despite near to identical ICP waveform in Sensors 1 and 2.

Methods

The study enrolled patients with aneurysmal subarachnoid hemorrhage in need of continuous ICP monitoring as part of their intensive care management. The two sensors were placed close to each other in the brain parenchyma via the same burr hole. The monitoring was performed as long as needed from a clinical perspective and the ICP recordings were stored digitally for analysis. For every patient the mean ICP as well as the various ICP wave parameters of the two sensors were compared.

Results

Sixteen patients were monitored median 164 hours (ranges 70 – 364 hours). Major BPEs, as defined by marked differences in mean ICP despite similar ICP waveform, were seen in 9 of them (56%). The BPEs were of magnitudes that had the potential to alter patient management.

Conclusions

Baseline Pressure Errors (BPEs) occur in a significant number of patients undergoing continuous ICP monitoring and they may alter patient management. The current practice of measuring ICP against a baseline pressure does not comply with the concept of State of the Art. Monitoring of the ICP waves ought to become the new State of the Art as they are not influenced by BPEs.

Brain monitoring: do we need a hole? An update on invasive and noninvasive brain monitoring modalities

The ability to measure reliably the changes in the physical and biochemical environment after a brain injury is of great value in the prevention, treatment, and understanding of the secondary injuries. Three categories of multimodal brain monitoring exist: direct signals which are monitored invasively; variables which may be monitored noninvasively; and variables describing brain pathophysiology which are not monitored directly but are calculated at the bedside by dedicated computer software. Intracranial pressure (ICP) monitoring, either as stand-alone value or study of a dynamic trend, has become an important diagnostic tool in the diagnosis and management of multiple neurological conditions. Attempts have been made to measure ICP non-invasively, but this is not a clinical reality yet. There is contrasting evidence that monitoring of ICP is associated with better outcome, and further RCTs based on management protocol are warranted. Computer bedside calculation of “secondary parameters” has shown to be potentially helpful, particularly in helping to optimize “CPP-guided therapy.” In this paper we describe the most popular invasive and non invasive monitoring modalities, with great attention to their clinical interpretation based on the current published evidence.

Invasive and ultrasound based monitoring of the intracranial pressure in an experimental model of epidural hematoma progressing towards brain tamponade on rabbits

INTRODUCTION

An experimental epidural hematoma model was used to study the relation of ultrasound indices, namely, transcranial color-coded-Doppler (TCCD) derived pulsatility index (PI), optic nerve sheath diameter (ONSD), and pupil constriction velocity (V) which was derived from a consensual sonographic pupillary light reflex (PLR) test with invasive intracranial pressure (ICP) measurements.

MATERIAL AND METHODS

Twenty rabbits participated in the study. An intraparenchymal ICP catheter and a 5F Swan-Ganz catheter (SG) for the hematoma reproduction were used. We successively introduced 0.1 mL increments of autologous blood into the SG until the Cushing reaction occurred. Synchronous ICP and ultrasound measurements were performed accordingly.

RESULTS

A constant increase of PI and ONSD and a decrease of V values were observed with increased ICP values. The relationship between the ultrasound variables and ICP was exponential; thus curved prediction equations of ICP were used. PI, ONSD, and V were significantly correlated with ICP (r² = 0.84 ± 0.076, r² = 0.62 ± 0.119, and r² = 0.78 ± 0.09, resp. (all P < 0.001)).

CONCLUSION

Although statistically significant prediction models of ICP were derived from ultrasound indices, the exponential relationship between the parameters underpins that results should be interpreted with caution and in the current experimental context.

Management of increased intracranial pressure

OPINION STATEMENT

After brain injury, neurologic intensive care focuses on the detection and treatment of secondary brain insults that may compound the initial injury. Increased intracranial pressure (ICP) contributes to secondary brain injury by causing brain ischemia, hypoxia, and metabolic dysfunction. Because ICP is easily measured at the bedside, it is the target of numerous pharmacologic and surgical interventions in efforts to improve brain physiology and limit secondary injury. However, ICP may not adequately reflect the metabolic health of the underlying brain tissue, particularly in cases of focal brain injury. As a result, ICP control alone may be insufficient to impact patients' long-term recovery. Further studies are needed to better understand the combination of cerebral, hemodynamic, and metabolic markers that are best utilized to ensure optimal brain and systemic recovery and overall patient outcome after brain injury.

Neurotrauma - a multidisciplinary disease

Traumatic brain injury is one of the most important diseases of our time, both in terms of morbidity, mortality and economic loss. Public health policy is key to reducing its incidence. Integrated multidisciplinary clinical care is vital to minimise its morbidity and mortality.

Preventing cerebral oedema in acute liver failure: the case for quadruple-H therapy

Severe cerebral oedema is a life-threatening complication of acute liver failure. Hyperammonaemia and cerebral hyperaemia are major contributing factors. A multimodal approach, which incorporates hyperventilation, haemodiafiltration, hypernatraemia and hypothermia (quadruple-H therapy), may prevent or attenuate severe cerebral oedema. This approach is readily administered by critical care clinicians and is likely to be more effective than the use of single therapies. Targeting of PaCO2 in the mild hyperventilation range, as seen in acute liver failure patients before intubation, aims to minimise hyperaemic cerebral oedema. Haemodiafiltration aims to achieve the rapid control of elevated blood ammonia concentrations by its removal and to reduce production via the lowering of core temperature. The administration of concentrated saline increases serum tonicity and further reduces cerebral swelling. In addition, the pathologically increased cerebral blood-flow is further attenuated by therapeutic hypothermia. The combination of all four treatments in a multimodal approach may be a safe and effective means of attenuating or treating the cerebral oedema of acute liver failure and preventing death from neurological complications.