Effect of hyperventilation, mannitol, and ventriculostomy drainage on cerebral blood flow after head injury

Escalate and De-Escalate Therapies for Intracranial Pressure Control in Traumatic Brain Injury

Severe traumatic brain injury (TBI) is frequently associated with an elevation of intracranial pressure (ICP), followed by cerebral perfusion pressure (CPP) reduction. Invasive monitoring of ICP is recommended to guide a step-by-step “staircase approach” which aims to normalize ICP values and reduce the risks of secondary damage. However, if such monitoring is not available clinical examination and radiological criteria should be used. A major concern is how to taper the therapies employed for ICP control. The aim of this manuscript is to review the criteria for escalating and withdrawing therapies in TBI patients. Each step of the staircase approach carries a risk of adverse effects related to the duration of treatment. Tapering of barbiturates should start once ICP control has been achieved for at least 24 h, although a period of 2–12 days is often required. Administration of hyperosmolar fluids should be avoided if ICP is normal. Sedation should be reduced after at least 24 h of controlled ICP to allow neurological examination. Removal of invasive ICP monitoring is suggested after 72 h of normal ICP. For patients who have undergone surgical decompression, cranioplasty represents the final step, and an earlier cranioplasty (15–90 days after decompression) seems to reduce the rate of infection, seizures, and hydrocephalus.

Guidelines for the Acute Treatment of Cerebral Edema in Neurocritical Care Patients

BACKGROUND

Acute treatment of cerebral edema and elevated intracranial pressure is a common issue in patients with neurological injury. Practical recommendations regarding selection and monitoring of therapies for initial management of cerebral edema for optimal efficacy and safety are generally lacking. This guideline evaluates the role of hyperosmolar agents (mannitol, HTS), corticosteroids, and selected non-pharmacologic therapies in the acute treatment of cerebral edema. Clinicians must be able to select appropriate therapies for initial cerebral edema management based on available evidence while balancing efficacy and safety.

METHODS

The Neurocritical Care Society recruited experts in neurocritical care, nursing, and pharmacy to create a panel in 2017. The group generated 16 clinical questions related to initial management of cerebral edema in various neurological insults using the PICO format. A research librarian executed a comprehensive literature search through July 2018. The panel screened the identified articles for inclusion related to each specific PICO question and abstracted necessary information for pertinent publications. The panel used GRADE methodology to categorize the quality of evidence as high, moderate, low, or very low based on their confidence that the findings of each publication approximate the true effect of the therapy.

RESULTS

The panel generated recommendations regarding initial management of cerebral edema in neurocritical care patients with subarachnoid hemorrhage, traumatic brain injury, acute ischemic stroke, intracerebral hemorrhage, bacterial meningitis, and hepatic encephalopathy.

CONCLUSION

The available evidence suggests hyperosmolar therapy may be helpful in reducing ICP elevations or cerebral edema in patients with SAH, TBI, AIS, ICH, and HE, although neurological outcomes do not appear to be affected. Corticosteroids appear to be helpful in reducing cerebral edema in patients with bacterial meningitis, but not ICH. Differences in therapeutic response and safety may exist between HTS and mannitol. The use of these agents in these critical clinical situations merits close monitoring for adverse effects. There is a dire need for high-quality research to better inform clinicians of the best options for individualized care of patients with cerebral edema.

Cerebral Vascular Changes During Acute Intracranial Pressure Drop

OBJECTIVE

This study applied a new external ventricular catheter, which allows intracranial pressure (ICP) monitoring and cerebral spinal fluid (CSF) drainage simultaneously, to study cerebral vascular responses during acute CSF drainage.

METHODS

Six patients with 34 external ventricular drain (EVD) opening sessions were retrospectively analyzed. A published algorithm was used to extract morphological features of ICP recordings, and a template-matching algorithm was applied to calculate the likelihood of cerebral vasodilation index (VDI) and cerebral vasoconstriction index (VCI) based on the changes of ICP waveforms during CSF drainage. Power change (∆P) of ICP B-waves after EVD opening was also calculated. Cerebral autoregulation (CA) was assessed through phase difference between arterial blood pressure (ABP) and ICP using a previously published wavelet-based algorithm.

RESULTS

The result showed that acute CSF drainage reduced mean ICP (P = 0.016) increased VCI (P = 0.02) and reduced ICP B-wave power (P = 0.016) significantly. VCI reacted to ICP changes negatively when ICP was between 10 and 25 mmHg, and VCI remained unchanged when ICP was outside the 10-25 mmHg range. VCI negatively (r = - 0.44) and VDI positively (r = 0.82) correlated with ∆P of ICP B-waves, indicating that stronger vasoconstriction resulted in bigger power drop in ICP B-waves. Better CA prior to EVD opening triggered bigger drop in the power of ICP B-waves (r = - 0.612).

CONCLUSIONS

This study demonstrates that acute CSF drainage reduces mean ICP, and results in vasoconstriction which can be detected through an index, VCI. Cerebral vessels actively respond to ICP changes or cerebral perfusion pressure (CPP) changes in a certain range; beyond which, the vessels are insensitive to the changes in ICP and CPP.

The Evolution of the Role of External Ventricular Drainage in Traumatic Brain Injury

External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.

Management of severe traumatic brain injury (first 24hours)

The latest French Guidelines for the management in the first 24hours of patients with severe traumatic brain injury (TBI) were published in 1998. Due to recent changes (intracerebral monitoring, cerebral perfusion pressure management, treatment of raised intracranial pressure), an update was required. Our objective has been to specify the significant developments since 1998. These guidelines were conducted by a group of experts for the French Society of Anesthesia and Intensive Care Medicine (Société francaise d'anesthésie et de réanimation [SFAR]) in partnership with the Association de neuro-anesthésie-réanimation de langue française (ANARLF), The French Society of Emergency Medicine (Société française de médecine d'urgence (SFMU), the Société française de neurochirurgie (SFN), the Groupe francophone de réanimation et d'urgences pédiatriques (GFRUP) and the Association des anesthésistes-réanimateurs pédiatriques d'expression française (ADARPEF). The method used to elaborate these guidelines was the Grade^® method. After two Delphi rounds, 32 recommendations were formally developed by the experts focusing on the evaluation the initial severity of traumatic brain injury, the modalities of prehospital management, imaging strategies, indications for neurosurgical interventions, sedation and analgesia, indications and modalities of cerebral monitoring, medical management of raised intracranial pressure, management of multiple trauma with severe traumatic brain injury, detection and prevention of post-traumatic epilepsia, biological homeostasis (osmolarity, glycaemia, adrenal axis) and paediatric specificities.

Effect of Cerebrospinal Fluid Drainage on Brain Tissue Oxygenation in Traumatic Brain Injury

The effectiveness of cerebrospinal fluid (CSF) drainage in lowering high intracranial pressure (ICP) is well established in severe traumatic brain injury (TBI). Recently, however, the use of external ventricular drains (EVDs) and ICP monitors in TBI has come under question. The aim of this retrospective study was to investigate the effect of CSF drainage on brain tissue oxygenation (PbtO₂). Using a multi-modality monitoring system, we continuously monitored PbtO₂ and parenchymal ICP during CSF drainage events via a ventriculostomy in 40 patients with severe TBI. Measurements were time-locked continuous recordings on a Component Neuromonitoring System in a neuroscience intensive care unit. We further selected for therapeutic CSF drainage events initiated at ICP values above 25 mm Hg and analyzed the 4-min periods before and after drainage for the physiologic variables ICP, cerebral perfusion pressure (CPP), and PbtO₂. We retrospectively identified 204 CSF drainage events for ICP EVD-opening values greater than 25 mm Hg in 23 patients. During the 4 min of opened EVD, ICP decreased by 5.7 ± 0.6 mm Hg, CPP increased by 4.1 ± 1.2 mm Hg, and PbtO₂ increased by 1.15 ± 0.26 mm Hg. ICP, CPP, and PbtO₂ all improved with CSF drainage at ICP EVD-opening values above 25 mm Hg. Although the average PbtO₂ changes were small, a clinically significant change in PbtO₂ of 5 mm Hg or greater occurred in 12% of CSF drainage events, which was correlated with larger decreases in ICP, displaying a complex relationship between ICP and PbtO₂ that warrants further studies.

Efficacy of different hypertonic solutes in the treatment of refractory intracranial hypertension in severe head injury patients: A comparative study of 2ml/kg 7.5% hypertonic saline and 2ml/kg 20% mannitol

A prospective, randomized study to evaluate the clinical benefit of increasing the osmotic load of the hypertonic solution administered for the treatment of refractory intracranial hypertension episodes in patients with severe head injury. 25 patients with severe head injury and persistent coma, admitted in a Neurocritical Care Unit of a Tertiary Care Hospital, who required infusions of osmotic agents to treat episodes of intracranial hypertension resistant to well defined standard modes of therapy were randomly allocated to one of the two groups to receive isovolume infusions of either 7.5% hypertonic saline solution; HS [2400 mOsm/kg H2O] or 20% mannitol [1160 mOsm/kg of H2O] given 2ml/kg of either solution, i.e. 331.5 +/− 35.4 mOsm of hypertonic saline or 174.2 +/− 18 mOsm of mannitol per infusion. The variables recorded in the study were the duration and number of episodes of intracranial hypertension per day during the study period, which was stopped after the last episode of intracranial hypertension was recorded from intracranial pressure recording or after the allocated treatment failure. Patients of HS group were monitored for 7 +/− 6 days and those in the mannitol group for 8 +/− 5 days [p=NS]. The rate of failure for each treatment was also evaluated which was defined as the persistence of intracranial hypertension despite the two successive infusions of the same osmotic agent. The mean number of osmotic solute infusions was 3.4 +/− 4.5 in the HS group and 3.8 +/− 5.1 in mannitol group p=NS]. The mean number [7.1+/-2.9 vs. 14.6+/−3.4] of episodes of intracranial hypertension per day and the duration of such episode [62.6+/−28.1 vs. 93.4+/−37.2 min] was also significantly lower in the HS group [p<0.05]. The numbers of treatment failures were significantly lower in HS group: 1 out of 14 patients vs. 6 out of 11 patients [p<0.01]. In this study we have found that in patients with severe head injury requiring treatment with hypertonic solute for refractory intracranial hypertension, 2ml/kg body weight of 7.5% HS [356 +/− 14 mOsm] was more effective than giving 2ml/kg 20% mannitol [178 +/− 11mOsm]. Within the limitations of present study, the collected data suggest that giving 2ml/kg HS solution is an effective and safe initial treatment for intracranial hypertension episodes in head injury patients when there is indication of osmotherapy.

Multimodal neurologic monitoring

Neurocritical care has two main objectives. Initially, the emphasis is on treatment of patients with acute damage to the central nervous system whether through infection, trauma, or hemorrhagic or ischemic stroke. Thereafter, attention shifts to the identification of secondary processes that may lead to further brain injury, including fever, seizures, and ischemia, among others. Multimodal monitoring is the concept of using various tools and data integration to understand brain physiology and guide therapeutic interventions to prevent secondary brain injury. This chapter will review the use of electroencephalography, intracranial pressure monitoring, brain tissue oxygenation, cerebral microdialysis and neurochemistry, near-infrared spectroscopy, and transcranial Doppler sonography as they relate to neuromonitoring in the critically ill. The concepts and design of each monitor, in addition to the patient population that may most benefit from each modality, will be discussed, along with the various tools that can be used together to guide individualized patient treatment options. Major clinical trials, observational studies, and their effect on clinical outcomes will be reviewed. The future of multimodal monitoring in the field of bioinformatics, clinical research, and device development will conclude the chapter.

Management of Elevated Intracranial Pressure

Elevated intracranial pressure (ICP) is a primary cause of morbidity and mortality for many neurologic disorders. The relationship between ICP and brain volume is influenced by autoregulatory processes that can become dysfunctional. As a result, neurologic damage can occur by systemic and intracranial insults such as ischemia and excitatory amino acids. Therefore, survival is dependent on optimizing ICP and cerebral perfusion pressure. Treatment of intracranial hypertension requires intensive monitoring and aggressive therapy. Intracranial pressure monitoring techniques such as intraventricular catheters are useful for determining ICP elevations before changes in vital signs and neurologic status. Therapeutic modalities, generally aimed at reducing cerebral blood volume, brain tissue, and cerebrospinal fluid (CSF) volume, include nonpharmacologic (CSF removal, controlled hyperventilation, and elevating the patient’s head) and pharmacologic management. Mannitol and sedation are first-line agents used to lower ICP. Barbiturate coma may be beneficial in patients with elevated ICP refractory to conventional treatment. The use of prophylactic antiseizure therapy and optimal nutrition prevents significant complication. Currently, investigations are directed at discovering useful neuroprotective agents that prevent secondary neurologic injury.

Monitoring of brain and systemic oxygenation in neurocritical care patients

Maintenance of adequate oxygenation is a mainstay of intensive care, however, recommendations on the safety, accuracy, and the potential clinical utility of invasive and non-invasive tools to monitor brain and systemic oxygenation in neurocritical care are lacking. A literature search was conducted for English language articles describing bedside brain and systemic oxygen monitoring in neurocritical care patients from 1980 to August 2013. Imaging techniques e.g., PET are not considered. A total of 281 studies were included, the majority described patients with traumatic brain injury (TBI). All tools for oxygen monitoring are safe. Parenchymal brain oxygen (PbtO2) monitoring is accurate to detect brain hypoxia, and it is recommended to titrate individual targets of cerebral perfusion pressure (CPP), ventilator parameters (PaCO2, PaO2), and transfusion, and to manage intracranial hypertension, in combination with ICP monitoring. SjvO2 is less accurate than PbtO2. Given limited data, NIRS is not recommended at present for adult patients who require neurocritical care. Systemic monitoring of oxygen (PaO2, SaO2, SpO2) and CO2 (PaCO2, end-tidal CO2) is recommended in patients who require neurocritical care.

Evaluation of the impact of implementing the emergency medical services traumatic brain injury guidelines in Arizona: the Excellence in Prehospital Injury Care (EPIC) study methodology

Traumatic brain injury (TBI) exacts a great toll on society. Fortunately, there is growing evidence that the management of TBI in the early minutes after injury may significantly reduce morbidity and mortality. In response, evidence-based prehospital and in-hospital TBI treatment guidelines have been established by authoritative bodies. However, no large studies have yet evaluated the effectiveness of implementing these guidelines in the prehospital setting. This article describes the background, design, implementation, emergency medical services (EMS) treatment protocols, and statistical analysis of a prospective, controlled (before/after), statewide study designed to evaluate the effect of implementing the EMS TBI guidelines-the Excellence in Prehospital Injury Care (EPIC) study (NIH/NINDS R01NS071049, "EPIC"; and 3R01NS071049-S1, "EPIC4Kids"). The specific aim of the study is to test the hypothesis that statewide implementation of the international adult and pediatric EMS TBI guidelines will significantly reduce mortality and improve nonmortality outcomes in patients with moderate or severe TBI. Furthermore, it will specifically evaluate the effect of guideline implementation on outcomes in the subgroup of patients who are intubated in the field. Over the course of the entire study (~9 years), it is estimated that approximately 25,000 patients will be enrolled.

Mitigating effects of external ventricular drain usage in the management of severe head injury

BACKGROUND

Cerebrospinal fluid (CSF) drainage has been variably employed to lower intracranial pressure (ICP) in patients with severe head injury. The efficacy of this manoeuvre remains under-explored (Brain Trauma Foundation Recommendation-optional treatment). This work seeks to report the results of CSF drainage via external ventricular drain (EVD) in severe head injury in comparison to other treatment options.

METHODS

Retrospective observational comparative study of all consecutive patients admitted to a major trauma centre with severe traumatic brain injury over a period of 12 months.

RESULTS

Out of a total 139 patients, 33 had delayed elevation of ICP despite conventional medical therapy, 16 patients were treated with EVD insertion (4 placed under AxiEM image guidance [Medtronic]) and 17 received either decompressive craniectomy or barbiturate coma. Subsequently, two patients with decompression had further ICP elevation and needed EVD. Two patients with EVD had raised ICP-one underwent decompression and the other was treated with barbiturate coma. One patient with EVD developed infection, which was successfully treated. Patients treated with EVD had a lower risk of needing definitive treatment for ICP control, i.e. decompressive craniectomy or barbiturate coma.

CONCLUSIONS

EVD was a safe and less invasive procedure, and achieved sustained control of ICP in this patient group.

Mannitol for acute traumatic brain injury

BACKGROUND

Mannitol is sometimes effective in reversing acute brain swelling, but its effectiveness in the ongoing management of severe head injury remains unclear. There is evidence that, in prolonged dosage, mannitol may pass from the blood into the brain, where it might cause increased intracranial pressure.

OBJECTIVES

To assess the effects of different mannitol therapy regimens, of mannitol compared to other intracranial pressure (ICP) lowering agents, and to quantify the effectiveness of mannitol administration given at other stages following acute traumatic brain injury.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (OvidSP), EMBASE (OvidSP), ISI Web of Science (SCI-EXPANDED & CPCI-S) and PubMed. We checked reference lists of trials and review articles, and contacted authors of trials. The search was updated on the 20th April 2009.

SELECTION CRITERIA

Randomised controlled trials of mannitol, in patients with acute traumatic brain injury of any severity. The comparison group could be placebo-controlled, no drug, different dose, or different drug. We excluded cross-over trials, and trials where the intervention was started more than eight weeks after injury.

DATA COLLECTION AND ANALYSIS

We independently rated quality of allocation concealment and extracted the data. Relative risks (RR) and 95% confidence intervals (CI) were calculated for each trial on an intention to treat basis.

MAIN RESULTS

We identified four eligible randomised controlled trials. One trial compared ICP-directed therapy to 'standard care' (RR for death = 0.83; 95% CI 0.47 to 1.46). One trial compared mannitol to pentobarbital (RR for death = 0.85; 95% CI 0.52 to 1.38). One trial compared mannitol to hypertonic saline (RR for death = 1.25; 95% CI 0.47 to 3.33). One trial tested the effectiveness of pre-hospital administration of mannitol against placebo (RR for death = 1.75; 95% CI 0.48 to 6.38).

AUTHORS' CONCLUSIONS

Mannitol therapy for raised ICP may have a beneficial effect on mortality when compared to pentobarbital treatment, but may have a detrimental effect on mortality when compared to hypertonic saline. ICP-directed treatment shows a small beneficial effect compared to treatment directed by neurological signs and physiological indicators. There are insufficient data on the effectiveness of pre-hospital administration of mannitol.

Decompressive craniectomy – friend or foe?

Decompressive craniectomy (DC) is the surgical management removing part of the skull vault over a swollen brain used to treat elevated intracranial pressure that is unresponsive to maximal medical therapy. The commonest indication for DC is traumatic brain injury (TBI) or middle cerebral artery (MCA) infarction, though DC has been reported to have been used for treatment of aneurysmal subarachnoid haemorrhage and venous infarction. Despite an increasing number of reports supportive of DC, the controversy over the suitability of the procedure and criteria for patient selection remains unresolved. Although the majority of published studies are retrospective, the recent publication of several randomised prospective studies prompts a re-evaluation of the use of DC. We review the literature concerning the pathophysiology, indication, surgical techniques and timing, complications and long-term effects of DC (including reversal with cranioplasty), in order to rationalise its use. We conclude that at the time of this review, though we cannot support the routine use of DC in TBI or MCA stroke, there is evidence that early and aggressive use of DC in TBI patients with intracranial haematomas or younger malignant MCA stroke patients may improve outcome. Though the results of the DECRA trial suggest that primary DC may worsen outcome, the decision to perform DC after diffuse TBI is still individualised. We await the results of the RESCUEicp trial to ascertain whether an evidence-based protocol for its use can be agreed in the future.

Contemporary management of traumatic intracranial hypertension: is there a role for therapeutic hypothermia?

OBJECTIVE

Intracranial hypertension (ICH) remains the single most difficult therapeutic challenge for the acute management of severe traumatic brain injury (TBI). We reviewed the published trials of therapeutic moderate hypothermia to determine its effect on ICH and compared its efficacy to other commonly used therapies for ICH.

METHODS

A PubMed database search was done using various combinations of the search terms "brain injury," "therapeutic hypothermia," "intracranial hypertension," "barbiturates," "mannitol," "hypertonic saline," "hyperventilation," "decompressive craniectomy," and "CSF drainage."

RESULTS

We identified 11 prospective randomized clinical TBI trials comparing hypothermia vs. normothermia treatment for which intracranial pressure (ICP) data was provided, and 6 prospective cohort studies that provided ICP data before and during hypothermia treatment. In addition, we identified 37 clinical TBI studies of lumbar CSF drainage, mannitol, hyperventilation, barbiturates, hypertonic saline, and decompressive craniectomy that provided pre- and posttreatment ICP data. Hypothermia was at least as effective as the traditional therapies for ICH (hyperventilation, mannitol, and barbiturates), but was less effective than hypertonic saline, lumbar CSF drainage, and decompressive craniectomy. Ultimately, however, therapeutic hypothermia does appear to have a favorable risk/benefit profile.

CONCLUSION

Therapeutic moderate hypothermia is as effective, or more effective, than most other treatments for ICH. If used for 2-3 days or less there is no evidence that it causes clinically significant adverse events. The lack of consistent evidence that hypothermia improves long-term neurologic outcome should not preclude consideration of its use for the primary treatment of ICH since no other ICP therapy is held to this standard.

Cerebral hemodynamic and metabolic effects of equi-osmolar doses mannitol and 23.4% saline in patients with edema following large ischemic stroke

INTRODUCTION

Cerebral edema after ischemic stroke is frequently treated with mannitol and hypertonic saline (HS); however, their relative cerebrovascular and metabolic effects are incompletely understood, and may operate independent of their ability to lower intracranial pressure.

METHODS

We compared the effects of 20% mannitol and 23.4% saline on cerebral blood flow (CBF), blood volume (CBV), oxygen extraction fraction (OEF), and oxygen metabolism (CMRO(2)), in nine ischemic stroke patients who deteriorated and had >2 mm midline shift on imaging. (15)O-PET was performed before and 1 h after administration of randomly assigned equi-osmolar doses of mannitol (1.0 g/kg) or 23.4% saline (0.686 mL/kg).

RESULTS

Baseline CBF values (ml/100g/min) in the infarct core, periinfarct region, remaining ipsilateral hemisphere, and contralateral hemisphere in the mannitol group were 5.0 ± 3.9, 25.6 ± 4.4, 35.6 ± 8.6, and 45.5 ± 2.2, respectively, and in the HS group were 8.3 ± 9.8, 35.3 ± 10.9, 38.2 ± 15.1, and 35.2 ± 12.4, respectively. There was a trend for CBF to rise in the contralateral hemisphere after mannitol from 45.5 ± 12.2 to 57.6 ± 21.7, P = 0.098, but not HS. CBV, OEF, and CMRO(2) did not change after administration of either agent. Change in CBF in the contralateral hemisphere after osmotic therapy was strongly correlated with baseline blood pressure (R (2)= 0.879, P = 0.002).

CONCLUSIONS

We conclude that at higher perfusion pressures, osmotic agents may raise CBF in non-ischemic tissue. We conclude that at higher perfusion pressures, osmotic agents may raise CBF in non-ischemic tissue.

Treatment and outcomes for pediatric head injuries in Mississippi

OBJECT

This report summarizes the treatments and outcomes of a large series of patients with pediatric head injuries (PHIs), who were admitted to a tertiary pediatric trauma center at the University of Mississippi Medical Center from January 1, 2003 through December 31, 2006.

METHODS

Data were retrieved from the Department of Neurosurgery's Brain Trauma Registry (BTR) on patients who are ≤16 years old. Data include Glasgow Coma Scale (GCS) and injury severity scores (ISS) on admission and Glasgow Outcome Scale (GOS) scores at 6 months follow-up.

RESULTS

The BTR registered 554 patients with accidental and nonaccidental PHIs. Follow-up was complete in 98.2%. Aggressive first-tier management with ventricular drainage was used to lower intracranial pressure. Vasopressors were used only to correct hypotension. Second-tier therapies were used infrequently. Craniectomies (14 patients) were associated with good outcomes (GOS 4-5) in nine patients; hypothermia (six patients) and barbiturate (four patients) therapies were ineffective. All 439 patients with ISS <25 showed good outcomes. Fifteen of 16 patients with GCS >8 and ISS ≥25 had good outcomes. In 134 patients with severe PHIs (GCS ≤8), all 45 with ISS <25 and 46 with ISS ≥25 showed good outcomes. Forty-three patients with GCS ≤8 and ISS ≥25 had poor outcomes. Of these patients, 38 died; 22 died within 3 days of admission.

CONCLUSIONS

This study indicated that poor outcomes occurred only in PHIs with severe generalized trauma. While 28.4% of patients with GSC ≤8 died, more than half of these sustained nonsurvivable injuries. Aggressive medical management with ventricular drainage was the mainstay of therapy.

Management of raised intracranial pressure

Appropriate management of raised intracranial pressure begins with stabilization of the patient and simultaneous assessment of the level of sensorium and the cause of raised intracranial pressure. Stabilization is initiated with securing the airway, ventilation and circulatory function. The identification of surgically remediable conditions is a priority. Emergent use of external ventricular drain or ventriculo-peritoneal shunt may be lifesaving in selected patients. In children with severe coma, signs of herniation or acutely elevated intracranial pressure, treatment should be started prior to imaging or invasive monitoring. Emergent use of hyperventilation and mannitol are life saving in such situations. Medical management involves careful use of head elevation, osmotic agents, and avoiding hypotonic fluids. Appropriate care also includes avoidance of aggravating factors. For refractory intracranial hypertension, barbiturate coma, hypothermia, or decompressive craniectomy should be considered.

Acute management of acquired brain injury part I: an evidence-based review of non-pharmacological interventions

PRIMARY OBJECTIVE

To review the literature on non-pharmacological interventions used in acute settings to manage elevated intracranial pressure (ICP) and minimize cerebral damage in patients with acquired brain injury (ABI).

MAIN OUTCOMES

A literature search of multiple databases (CINAHL, EMBASE, MEDLINE and PSYCHINFO) and hand-searched articles covering the years 1980-2008 was performed. Peer reviewed articles were assessed for methodological quality using the PEDro scoring system for randomized controlled trials (RCTs) and the Downs and Black tool for RCTs and non-randomized trials. Levels of evidence were assigned and recommendations made.

RESULTS

Five non-invasive interventions for acute ABI management were assessed: adjusting head posture, body rotation (continuous rotational therapy and prone positioning), hyperventilation, hypothermia and hyperbaric oxygen. Two invasive interventions were also reviewed: cerebrospinal fluid (CSF) drainage and decompressive craniectomy (DC).

CONCLUSIONS

There is a paucity of information regarding non-pharmacological acute management of patients with ABI. Strong levels of evidence were found for only four of the seven interventions (decompressive craniectomy, cerebrospinal fluid drainage, hypothermia and hyperbaric oxygen) and only for specific components of their use. Further research into all interventions is warranted.

Emergency treatment options for pediatric traumatic brain injury

Traumatic brain injury is a leading killer of children and is a major public health problem around the world. Using general principles of neurocritical care, various treatment strategies have been developed to attempt to restore homeostasis to the brain and allow brain healing, including mechanical factors, cerebrospinal fluid diversion, hyperventilation, hyperosmolar therapies, barbiturates and hypothermia. Careful application of these therapies, normally in a step-wise fashion as intracranial injuries evolve, is necessary in order to attain maximal neurological outcome for these children. It is hopeful that new therapies, such as early hypothermia or others currently in preclinical trials, will ultimately improve outcome and quality of life for children after traumatic brain injury.

Long-term outcomes and prognostic factors in pediatric patients with severe traumatic brain injury and elevated intracranial pressure

OBJECT

The management strategies and outcomes in pediatric patients with elevated intracranial pressure (ICP) following severe traumatic brain injury (TBI) are examined in this study.

METHODS

This study was a retrospective review of a prospectively acquired pediatric trauma database. More than 750 pediatric patients with brain injury were seen over a 10-year period. Records were retrospectively reviewed to determine interventions for correcting ICP, and surviving patients were contacted prospectively to determine functional status and quality of life. Only patients with 2 years of follow-up were included in the study.

RESULTS

Ninety-six pediatric patients (age range 3-18 years) were identified with a Glasgow Coma Scale score<8 and elevated ICP>20 mm Hg on presentation. The mean injury severity score was 65 (range 30-100). All patients were treated using a standardized head injury protocol. The mean time course until peak ICP was 69 hours postinjury (range 2-196 hours). Intracranial pressure control was achieved in 82 patients (85%). Methods employed to achieve ICP control included maximal medical therapy (sedation, hyperosmolar therapy, and paralysis) in 34 patients (35%), ventriculostomy in 23 patients (24%), and surgery in 39 patients (41%). Fourteen patients (15%) had refractory ICP despite all interventions, and all of these patients died. Seventy-two patients (75%) were discharged from the hospital, whereas 24 (25%) died during hospitalization. Univariate and multivariate analysis revealed that the presence of vascular injury, refractory ICP, and cisternal effacement at presentation had the highest correlation with subsequent death (p<0.05). Mean follow-up was 53 months (range 11-126 months). Three patients died during the follow-up period (2 due to infections and 1 committed suicide). The mean 2-year Glasgow Outcome Scale score was 4 (median 4, range 1-5). The mean patient competency rating at follow-up was 4.13 out of 5 (median 4.5, range 1-4.8). Univariate analysis revealed that the extent of intracranial and systemic injuries had the highest correlation with long-term quality of life (p<0.05).

CONCLUSIONS

Controlling elevated ICP is an important factor in patient survival following severe pediatric TBI. The modality used for ICP control appears to be less important. Long-term follow-up is essential to determine neurocognitive sequelae associated with TBI.

Characterizing the dose-response relationship between mannitol and intracranial pressure in traumatic brain injury patients using a high-frequency physiological data collection system

Despite the widespread use of mannitol to treat elevated intracranial pressure (ICP), there is no consensus regarding the optimal dosage. The objective of this study was to retrospectively characterize the dose-response relationship between mannitol and ICP using data collected with a continuous high-frequency physiological data collection system. To this end, we measured ICP continuously in 28 patients with traumatic brain injury (TBI) who were given at least one dose of mannitol. Twenty TBI patients were given a total of 85 doses of 50 g of mannitol, and 18 patients were given 50 doses of 100 g. Some patients received both amounts. Cerebral perfusion pressure was maintained above 60 mm Hg. The average ICP was 22.0 +/- 10.6 mm Hg when mannitol was administered, fell immediately after dosing, and continued falling for approximately 30 min to 15.7 +/- 8.1 mm Hg across all patients. After 30 min, ICP was equal in the 100-g group (15.6 +/- 10.9) versus the 50-g group (15.7 +/- 6.3). However, at 100 min, ICP had increased in the 50-g group to nearly its initial value but was still lower in the 100-g group (18.6 +/- 7.6 vs. 14.2 +/- 6.7 mm Hg; p = 0.001). Osmotic agents such as mannitol have been used for decades to treat cerebral edema, but there has been no definitive quantitative information regarding the dosing of mannitol. In a large, retrospective study of high-frequency ICP data, we have quantitatively shown that mannitol's effect on ICP is dose-dependent and that higher doses provide a more durable reduction in ICP.

Does hyperventilation improve operating condition during supratentorial craniotomy? A multicenter randomized crossover trial

BACKGROUND

Hyperventilation has been an integral, but poorly validated part of neuroanesthetic practice. We conducted a two-period, crossover, randomized trial to evaluate surgeon-assessed brain bulk and measured intracranial pressure (ICP) in patients undergoing craniotomy for removal of supratentorial brain tumors during moderate hypocapnia or normocapnia.

METHODS

Two-hundred and seventy-five adult patients with supratentorial brain tumors were randomized to one of two treatment sequences: hyperventilation (arterial carbon dioxide tension, PaCO2 = 25 +/- 2 mm Hg) followed by normoventilation (PaCO2 = 37 +/- 2 mm Hg) or normoventilation followed by hyperventilation. Ventilation and end-tidal CO2 tension were kept constant for 20 min. Patients were also randomly assigned to receive a propofol infusion or isoflurane anesthesia. At the end of each study period, subdural ICP was measured and the neurosurgeon, blinded to the treatment group, was asked to rate the brain bulk using a four-point scale.

RESULTS

Using a generalized estimation equation model, we found that hyperventilation decreased the risk of increased brain bulk by 45%, P = 0.004, 95% confidence intervals 22% to 61%, and the number needed to treat was 8. The mean (+/-SD) ICP during hyperventilation, 12.3 +/- 8.1 mm Hg, was lower than that during normoventilation, 16.2 +/- 9.6 mm Hg, P < 0.001. Anesthetic regimen did not affect brain bulk assessment or ICP.

CONCLUSIONS

In patients with supratentorial brain tumors, intraoperative hyperventilation improves surgeon-assessed brain bulk which was associated with a decrease in ICP.

Dose-response relationship of mannitol and intracranial pressure: a metaanalysis

OBJECTIVE

Brain edema can increase intracranial pressure (ICP), potentially leading to ischemia, herniation, and death. Edema and elevated ICP are often treated with osmotic agents to remove water from brain tissue. Mannitol is the osmotic diuretic most commonly used in the intensive care unit; however, despite its clinical importance, treatment protocols vary from center to center, and the dose-response relationship is not understood. The goal of this metaanalysis was to aggregate and analyze data from studies in which authors have described the dose-response relationship between mannitol and ICP.

METHODS

The authors identified 18 studies that quantitatively characterized the dose-response relationship of mannitol and ICP. We also examined study designs and mannitol administration protocols.

RESULTS

Meta-regression found a weak linear relationship between change in ICP (delta ICP) and dose (delta ICP = 6.6 x dose - 1.1; p = 0.27, R(2) = 0.05). The lack of statistical significance could reflect the variation in protocols among studies and the variation in patients both within and among studies. However, the authors found a highly significant difference (p < 0.001) in decrease in ICP when the initial ICP was higher or lower than 30 mm Hg. Nonlinear regression suggested that ICP decrease is greatest shortly after mannitol is given (R(2) = 0.63). Finally, the authors found that recent studies tend to include fewer patients and set a lower ICP threshold for mannitol administration but report more parameters of interest; the duration of mannitol's effect was the most frequently unreported parameter.

CONCLUSIONS

Despite its clinical importance, the determination of the mannitol dose-response curve continues to be challenging for many reasons. This metaanalysis highlights the need for a consensus of methods and results required to determine this important relationship.

Ventriculostomy for control of raised ICP in acute traumatic brain injury

The aim of this study was to evaluate the effect of ventriculostomy on intracranial pressure (ICP), and related parameters, including cerebrospinal compensation, cerebral oxygenation (PbtO2) and metabolism (microdialysis) in patients with traumatic brain injury (TBI).

MATERIALS AND METHODS

Twenty-four patients with parenchymal ICP sensors were prospectively included in the study. Ventriculostomy was performed after failure to control ICP with initial measures. Monitoring parameters were digitally recorded before and after ventriculostomy and compared using appropriate tests.

RESULTS

In all patients ventriculostomy led to rapid reduction in ICP. Pooled mean daily values of ICP remained < 20mmHg for 72h after ventriculostomy and were lower than before (p < 0.001). In 11 out of 24 patients during the initial 24-h period following ventriculostomy an increase in ICP to values exceeding 20mmHg was observed. In the remaining 13 patients ICP remained stable, allowing reduction in the intensity of treatment. In this group ventriculostomy led to significant improvement in craniospinal compensation (RAP index), cerebral perfusion pressure and PbtO2. Improvement in lactate/pyruvate ratio, a marker of energy metabolism, was correlated with the increase in PbtO2.

CONCLUSION

Ventriculostomy is a useful ICP-lowering manoeuvre, with sustained ICP reduction and related physiological improvements achieved in > 50% of patients.

Subdural intracranial pressure monitoring in severe head injury: clinical experience with the Codman MicroSensor

BACKGROUND

Our main objective was to study the clinical outcome and complications of the subdural ICP monitoring with the CMS (Johnson and Johnson Medical Ltd, Raynhan, MA) in severe head injury.

METHODS

A retrospective analysis of patients with head injury with a GCS score of 8 or less was performed. Patients with severe systemic injury with hypotension (systolic blood pressure of <90 mm Hg on admission), a GCS score of 3 with fixed and dilated pupils after resuscitation, a GCS score of 3 to 4 whose family refused aggressive treatment, and those who were dead on arrival were excluded from this study. During the period from January 1997 to April 2004, 120 patients with severe head injuries were included and met criteria for insertion of a subdural ICP monitoring device (CMS).

RESULTS

A total of 120 patients (84 males and 36 females), aged 16 to 80 years old (mean, 43.8 +/- 14.4), were enrolled in the study. The average duration of ICP monitoring device use was 7.6 +/- 0.4 days (range, 2-14 days). The overall clinical outcomes of these patients were as follows: mortality rate, 13.5%; percentage of unfavorable outcomes, 17.3%; percentage of favorable outcomes, 69.2%. There were no complications such as CNS infection or hemorrhage in this study.

CONCLUSION

A subdural transducer-tipped catheter (CMS) can be used as the first-line equipment for monitoring ICP in patients with severe head injury. The clinical results are similar with other recent studies, but no complication such as infection or hemorrhage occurred in this study.

Hiérarchisation des traitements de l'hypertension intracrânienne chez le traumatisé crânien grave

The objective of the treatment of intracranial hypertension is to decrease intracranial pressure (ICP) while maintaining cerebral blood flow (CBF). Despite numerous treatments, none of them associates total efficiency and security. Systemic secondary cerebral injuries, which are responsible for cerebral ischemia, lead us to administer non specific treatments in order to optimize CBF and cerebral oxygenation. Thus, the goals are: 1) to maintain cerebral perfusion pressure> or =70 mmHg; 2) to control metabolic status by preventing hyperglycaemia, anaemia and hyperthermia; 3) to maintain normoxia and normocapnia (hypercapnia increases ICP and hypocapnia decreases CBF). Beside the neurosurgical evacuation of extra- and intraparenchymatous haematomas, osmotherapy and cerebrospinal fluid (CSF) evacuation are the two specific treatments of intracranial hypertension. Osmotherapy consists in an administration of a hypertonic solution which induces a decrease in cerebral water and finally in ICP. Mannitol (20%), which is the reference, associates osmotic and rheologic effects, and decreases CSF production too. Recent data conduct us to administer larger doses, between 0.7 and 1 g/kg in 15 minutes. Hypertonic saline solution associates osmotic effects and plasma volume loading. Thus, this solution is particularly appropriate in severe head injury with arterial hypotension. CBF evacuation decreases rapidly ICP without any major side-effect. Until now, there is no proof of a superior efficiency of a treatment for intracranial hypertension compared to another. Considering their mechanism of action, all of them are efficient but potentially dangerous too. Indeed, the choice between treatments depends on data which are issued from the multimodal monitoring. General non specific treatments are always necessary. Specific treatments are indicated if ICP is above 20-25 mmHg. Maintaining cerebral perfusion pressure represents the first therapeutic goal. If intracranial hypertension persists, evacuation of CBF or osmotherapy may be advocated. In case of refractory intracranial hypertension, it may be useful to deepen neurosedation. Controlled hypocapnia and barbiturates remain a third line therapy providing to monitor and maintain an appropriate CBF and cerebral oxygenation. Controlled hypothermia and decompressive craniectomy must be individually discussed.

Mannitol for acute traumatic brain injury

BACKGROUND

Mannitol is sometimes effective in reversing acute brain swelling, but its effectiveness in the ongoing management of severe head injury remains unclear. There is evidence that, in prolonged dosage, mannitol may pass from the blood into the brain, where it might cause increased intracranial pressure.

OBJECTIVES

To assess the effects of different mannitol therapy regimens, of mannitol compared to other intracranial pressure (ICP) lowering agents, and to quantify the effectiveness of mannitol administration given at other stages following acute traumatic brain injury.

SEARCH STRATEGY

The review drew on the search strategy for the Injuries Group as a whole. We checked reference lists of trials and review articles, and contacted authors of trials. The searches were last updated in March 2006.

SELECTION CRITERIA

Randomised controlled trials of mannitol, in patients with acute traumatic brain injury of any severity. The comparison group could be placebo-controlled, no drug, different dose, or different drug. We excluded cross-over trials, and trials where the intervention was started more than eight weeks after injury.

DATA COLLECTION AND ANALYSIS

We independently rated quality of allocation concealment and extracted the data. Relative risks (RR) and 95% confidence intervals (CI) were calculated for each trial on an intention to treat basis.

MAIN RESULTS

We identified four eligible randomised controlled trials. One trial compared ICP-directed therapy to 'standard care' (RR for death = 0.83; 95% CI 0.47 to 1.46). One trial compared mannitol to pentobarbital (RR for death = 0.85; 95% CI 0.52 to 1.38). One trial compared mannitol to hypertonic saline (RR for death = 1.25; 95% CI 0.47 to 3.33). One trial tested the effectiveness of pre-hospital administration of mannitol against placebo (RR for death = 1.75; 95% CI 0.48 to 6.38).

AUTHORS' CONCLUSIONS

Mannitol therapy for raised ICP may have a beneficial effect on mortality when compared to pentobarbital treatment, but may have a detrimental effect on mortality when compared to hypertonic saline. ICP-directed treatment shows a small beneficial effect compared to treatment directed by neurological signs and physiological indicators. There are insufficient data on the effectiveness of pre-hospital administration of mannitol.

Extracranial carotid Doppler ultrasound evaluation of cerebral blood flow volume in COPD patients

OBJECTIVE

Doppler ultrasound of extracranial internal carotid artery (ICA) and vertebral artery (VA) were performed and total cerebral blood flow volume (tCBFV) was evaluated in chronic obstructive pulmonary disease (COPD) patients. CBFV changes due to blood gas changes were also evaluated.

METHODS

Bilateral ICA and VA have been examined with 7.5 MHz linear array transducer in COPD patients. Angle-corrected time averaged flow velocity and cross-sectional areas of vessels have been measured. Flow volumes and tCBFV have been calculated. Flow velocities and waveform parameters have been measured.

RESULTS

tCBFV, anterior-posterior CBFVs, left-right ICA flow volumes, bilateral ICA and VA cross-sectional areas and left ICA peak-systolic velocity were significantly higher in COPD patients than control group. Among COPD patients tCBFVs were highest in hypoxemic-hypercapnic ones, and lowest in normocapnic ones. Bilateral VA flow volumes, bilateral ICA (except left ICA V(ps)) and VA flow velocities and waveform parameters were not different in COPD patients compared with control group. When compared among the subgroups of COPD patients, there were no significant differences for all parameters.

CONCLUSION

tCBFVs were found to be significantly higher in COPD patients. This increment which is probably due to balancing the oxygen deficit is low with hypoxemia and high with hypercapnia and hypoxemia. Particularly, bilateral ICA and VA cross-sectional area changes and increased left ICA V(ps) were considered as the main reason for increased tCBFV in COPD patients.

CURRENT CONTROVERSIES IN THE MANAGEMENT OF PATIENTS WITH SEVERE TRAUMATIC BRAIN INJURY

BACKGROUND

Traumatic brain injury is a major cause of mortality and morbidity, particularly among young men. The efficacy and safety of most of the interventions used in the management of patients with traumatic brain injury remain unproven. Examples include the 'cerebral perfusion pressure-targeted' and 'volume-targeted' management strategies for optimizing cerebrovascular haemodynamics and specific interventions, such as hyperventilation, osmotherapy, cerebrospinal fluid drainage, barbiturates, decompressive craniectomy, therapeutic hypothermia, normobaric hyperoxia and hyperbaric oxygen therapy.

METHODS

A review of the literature was performed to examine the evidence base behind each intervention.

RESULTS

There is no class I evidence to support the routine use of any of the therapies examined.

CONCLUSION

Well-designed, large, randomized controlled trials are needed to determine therapies that are safe and effective from those that are ineffective or harmful.

Intracranial pressure monitoring: why monitor?

Evidence suggests that the mortality and morbidity of acquired brain injury could be reduced if clinicians used an aggressive intracranial pressure guided approach to care. Despite nearly 50 years of evidence that intracranial pressure monitoring benefits patient care, only about half of the patients who could benefit are monitored. Some clinicians express concerns regarding risks such as bleeding, infections, and inaccuracy of the technology. Others cite cost as the reason. This article discusses the risks and benefits of intracranial pressure monitoring and the current state of evidence of why patients should be monitored.

Hyperventilation in head injury: a review

The aim of this review was to consider the effects of induced hypocapnia both on systemic physiology and on the physiology of the intracranial system. Hyperventilation lowers intracranial pressure (ICP) by the induction of cerebral vasoconstriction with a subsequent decrease in cerebral blood volume. The downside of hyperventilation, however, is that cerebral vasoconstriction may decrease cerebral blood flow to ischemic levels. Considering the risk-benefit relation, it would appear to be clear that hyperventilation should only be considered in patients with raised ICP, in a tailored way and under specific monitoring. Controversy exists, for instance, on specific indications, timing, depth of hypocapnia, and duration. This review has specific reference to traumatic brain injury, and is based on an extensive evaluation of the literature and on expert opinion.

In vivo multiparametric monitoring of brain functions under intracranial hypertension following mannitol administration

OBJECTIVE

Over the last 20 years, mannitol has replaced other osmotic diuretics. Its beneficial effects on intracranial pressure (ICP), cerebral perfusion pressure (CPP), cerebral blood flow (CBF) and brain metabolism are widely accepted. In the present study, we tested the effect of mannitol injection on brain hemodynamic, metabolic, ionic and electrical state in rats exposed to intracranial hypertension.

METHODS

The parameters monitored simultaneously included ICP, CBF using the laser Doppler flowmetry, mitochondrial NADH redox state by the fluorometric technique, extracellular K(+) and H(+) levels, DC potential, ECoG, blood pressure and calculated CPP. ICP was elevated to 30 mmHg for 30 minutes and mannitol was injected 15 minutes post-ICP elevation.

RESULTS

Our results showed that mannitol decreased ICP, and improved the levels of MAP, CPP and CBF. Moreover, mannitol completely prevented mortality following intracranial hypertension in rats.

CONCLUSION

It seems that the multiparametric monitoring approach, used in intracranial hypertension models, is an important tool for brain functional state evaluation.

The Impact of Prehospital Endotracheal Intubation on Outcome in Moderate to Severe Traumatic Brain Injury

BACKGROUND

Although early intubation to prevent the mortality that accompanies hypoxia is considered the standard of care for severe traumatic brain injury (TBI), the efficacy of this approach remains unproven.

METHODS

Patients with moderate to severe TBI (Head/Neck Abbreviated Injury Scale [AIS] score 3+) were identified from our county trauma registry. Logistic regression was used to explore the impact of prehospital intubation on outcome, controlling for age, gender, mechanism, Glasgow Coma Scale score, Head/Neck AIS score, Injury Severity Score, and hypotension. Neural network analysis was performed to identify patients predicted to benefit from prehospital intubation.

RESULTS

A total of 13,625 patients from five trauma centers were included; overall mortality was 22.9%, and 19.3% underwent prehospital intubation. Logistic regression revealed an increase in mortality with prehospital intubation (odds ratio, 0.36; 95% confidence interval, 0.32-0.42; p < 0.001). This was true for all patients, for those with severe TBI (Head/Neck AIS score 4+ and/or Glasgow Coma Scale score of 3-8), and with exclusion of patients transported by aeromedical crews. Patients intubated in the field versus the emergency department had worse outcomes. Neural network analysis identified a subgroup of patients with more significant injuries as potentially benefiting from prehospital intubation.

CONCLUSION

Prehospital intubation is associated with a decrease in survival among patients with moderate-to-severe TBI. More critically injured patients may benefit from prehospital intubation but may be difficult to identify prospectively.

Management of Increased Intracranial Pressure in the Critically Ill Child With an Acute Neurological Injury

Increased intracranial pressure reflects the presence of mass effect in the brain and is associated with a poor outcome in children with acute neurological injury. If sustained, it has a negative effect on cerebral blood flow and cerebral perfusion pressure, can cause direct compression of vital cerebral structures, and can lead to herniation. The management of the patient with increased intracranial pressure involves the maintenance of an adequate cerebral perfusion pressure, prevention of intracranial hypertension, and optimization of oxygen delivery. This article reviews the neurological assessment, pathophysiology, and management of increased intracranial pressure in the critically ill child who has sustained an acute neurological injury.

Randomized, controlled trial on the effect of a 20% mannitol solution and a 7.5% saline/6% dextran solution on increased intracranial pressure after brain injury*

OBJECTIVE

The aim of this pilot study was to compare the effects of equimolar doses of hypertonic saline and dextran solution (HSD, Rescueflow) with 20% mannitol solution for reduction of increased intracranial pressure.

DESIGN

Prospective, randomized, controlled, crossover trial in the intensive care unit of a large teaching hospital.

SETTING

Academic hospital and tertiary referral center for neuroscience.

PATIENTS

Nine patients with an intracranial pressure of >20 mm Hg were recruited and received two treatments of each, HSD and 20% mannitol, in a randomized order.

INTERVENTION

Equimolar, rapid intravenous infusions of either 200 mL of 20% mannitol or 100 mL of 7.5% saline and 6% dextran-70 solution (HSD) over 5 mins.

MEASUREMENTS

Intracranial pressure, blood pressure, serum and urine sodium and osmolality, and urine output.

MAIN RESULTS

Treatments reduced intracranial pressure with both mannitol (median decrease, 7.5 mm Hg, 95% confidence interval, 5.8-11.8) and HSD (median decrease, 13 mm Hg; 95% confidence interval, 11.5-17.3). HSD caused a significantly greater decrease in intracranial pressure than mannitol (p = .044). HSD had a longer duration of effect than mannitol (p = .044).

CONCLUSION

When given in an equimolar, rapid, intravenous infusion, HSD reduces intracranial pressure more effectively than mannitol.

Managing elevated intracranial pressure

PURPOSE OF REVIEW

Elevated intracranial pressure is one of the major deteriorating factors in patients with intracerebral lesions. Therefore, every year many experimental and clinical studies are performed to identify the best method for managing elevated intracranial pressure in head-injured patients. The current review summarizes the most important recent findings for the treatment of increased intracranial pressure.

RECENT FINDINGS

The currently most discussed treatments of elevated intracranial pressure are the use of hypertonic saline, which seems to be equal to mannitol, the use of hypothermia, and the performance of decompressive craniectomy.

SUMMARY

The treatment strategy to manage increased intracranial pressure includes decisions about anaesthetics, ventilation, head and body position, hypothermia, the use of osmotic drugs and surgical procedures. Propofol seems to be suitable for the sedation of patients with elevated intracranial pressure. Sudden increases in intracranial pressure can be treated using hyperosmotic agents, high-dose thiopental, or short episodes of mild hyperventilation. Surgical decompression of the cranium seems to improve the outcome in patients below the age of 50 years, especially children.

Management of Increased Intracranial Pressure

Brain edema and the resulting increase in intracranial pressure may be the result of several conditions: head trauma, intracranial hemorrhage, embolic stroke, infections, tumors, and alterations in cerebral spinal fluid production or absorption. At times, these patients may be treated outside of the neurological intensive care unit (ICU) for a variety of reasons. Therefore, general critical care nurses may find themselves in the position of caring for these patients. Maintaining expertise outside of one's area of focus is increasingly difficult to do, and the non-neuro critical care nurse may be unfamiliar with some of the newer research findings and trends in treating these patients. The purpose of this article is to review several of the concepts of neurological care and to update critical care nurses in various newer approaches to caring for patients with increased intracranial pressure.

The impact of hypoxia and hyperventilation on outcome after paramedic rapid sequence intubation of severely head-injured patients

BACKGROUND

An increase in mortality has been documented in association with paramedic rapid sequence intubation (RSI) of severely head-injured patients. This analysis explores the impact of hypoxia and hyperventilation on outcome.

METHODS

Adult severely head-injured patients (Glasgow Coma Scale score of 3-8) unable to be intubated without neuromuscular blockade underwent paramedic RSI using midazolam and succinylcholine; rocuronium was administered after confirmation of tube position. Standard ventilation parameters were used for most patients; however, one agency instituted use of digital end-tidal carbon dioxide (ETCO2) and oxygen saturation (Spo2) monitoring during the trial. Each patient undergoing digital ETCO2/Spo2 monitoring was matched to three historical nonintubated controls on the basis of age, gender, mechanism, and Abbreviated Injury Scale scores for each of six body regions. Logistic regression was used to explore the impact of oxygen desaturation during laryngoscopy and postintubation hypocapnia and hypoxia on outcome. The relationship between hypocapnia and ventilatory rate was explored using linear regression and univariate analysis. In addition, trial patients and controls were compared with regard to mortality and the incidence of "good outcomes" using an odds ratio analysis.

RESULTS

Of the 426 trial patients, a total of 59 had complete ETCO2/Spo2 monitoring data; these were matched to 177 controls. Logistic regression revealed an association between the lowest ETCO2 value and final ETCO2 value and mortality. Matched-controls analysis confirmed an association between hypocapnia and mortality. A statistically significant association between ventilatory rate and ETCO2 value was observed (r = -0.13, p < 0.0001); the median ventilatory rate associated with the lowest recorded ETCO2 value was significantly higher than for all other ETCO2 values (27 mm Hg vs. 19 mm Hg, p < 0.0001). In addition, profound desaturations during RSI and hypoxia after intubation were associated with higher mortality than matched controls. Overall mortality was 41% for trial patients versus 22% for matched controls (odds ratio, 2.51; 95% confidence interval, 1.33-4.72; p = 0.004).

CONCLUSIONS

Hyperventilation and severe hypoxia during paramedic RSI are associated with an increase in mortality.

Air medical transport of severely head-injured patients undergoing paramedic rapid sequence intubation

INTRODUCTION

The San Diego Paramedic Rapid Sequence Intubation (RSI) Trial documented an increase in mortality with paramedic RSI of patients with severe traumatic brain injury. This analysis explores the impact of air medical transport of trial patients on outcome.

METHODS

Adult trauma victims with severe traumatic brain injury (Glasgow Coma Scale score of 3 to 8) were prospectively enrolled. Paramedics performed RSI using midazolam and succinylcholine; air medical crews could be called at the discretion of ground paramedics, generally for anticipated prolonged transports. Patients were matched to historical controls using the following parameters: age, gender, mechanism, injury of severity score, and abbreviated injury scale scores for each body system. Patients transported by air and ground were compared with regard to demographics, clinical parameters, vital signs, arterial blood gas data, and outcome.

RESULTS

A total of 336 patients were included (79 air medical and 257 ground transports). No significant differences arose between the groups with regard to demographic, clinical, vital sign, and arterial blood gas data. Air medical patients had decreased mortality (28% vs 31%, OR 0.9), and ground patients had increased mortality versus matched controls (33% vs 22%, OR 1.8). Discordant groups analysis revealed a statistically significant effect of transport personnel on outcome (P=.009). Neither advanced procedures nor the use of mannitol accounted for the improved outcomes; air medical crews used capnometry to guide ventilation on all study patients.

CONCLUSION

Air medical transport of severely head-injured patients undergoing paramedic RSI was associated with improved outcomes. Improved ventilation by capnometry may account for part of these improvements.

Traumatic brain injury in infants and children: mechanisms of secondary damage and treatment in the intensive care unit

Unfortunately no specific pharmacologic therapies are available for the treatment of TBI in patients. Current investigation of contemporary therapies for the treatment of TBI consists of recycling of previously tested therapies in the era of contemporary neurointensive care. These therapies include hypothermia, decompressive craniectomy, osmotherapy, and controlled hyperventilation. It is hoped that more detailed knowledge regarding the dominant pathophysiologic mechanisms associated with TBI-excitotoxicity, CBF dysregulation, oxidative stress, and programmed cell death-will catapult an efficacious intervention from the laboratory bench to the bedside. This intervention may be a potent agent targeting a single dominant pathway, a broad-spectrum intervention such as hypothermia, or, more likely, a combination of therapies. Meanwhile, practitioners must offer meticulous supportive neurointensive care using clinically proven therapies aimed at minimizing cerebral swelling for the management of pediatric patients who are victims of TBI.

Isovolume hypertonic solutes (sodium chloride or mannitol) in the treatment of refractory posttraumatic intracranial hypertension: 2 mL/kg 7.5% saline is more effective than 2 mL/kg 20% mannitol

OBJECTIVE

To evaluate the clinical benefit of increasing the osmotic load of the hypertonic solution administered for the treatment of refractory intracranial hypertension episodes in patients with severe head injury.

DESIGN

Prospective, randomized study.

SETTINGS

A trauma center in a university hospital.

PATIENTS

Twenty consecutive patients with head trauma and persistent coma who required infusions of an osmotic agent to treat episodes of intracranial hypertension resistant to well-conducted standard modes of therapy were studied. Intracranial hypertension was considered refractory when it persisted despite deep sedation, optimal hemodynamic status, and, in some patients, drainage of cerebral spinal fluid.

INTERVENTIONS

Patients were randomly assigned to receive isovolume infusions of either 7.5% hypertonic saline solution (2400 mOsm/kg/H(2)O) or 20% mannitol (1160 mOsm/kg/H(2)O). The patients were given 2 mL/kg (body weight) of either solution, i.e., 361 +/- 13 mOsm of saline or 175 +/- 12 mOsm of mannitol per injection.

MEASUREMENTS AND MAIN RESULTS

The main variables studied were the number and the duration of episodes of intracranial hypertension per day during the study period, which was stopped after the last episode of intracranial hypertension was recorded from intracranial pressure monitoring or after the allocated treatment failure. Patients in the HHS group were monitored for 7 +/- 5 days and those in the mannitol group for 7 +/- 6 days (not significant). The rate of failure for each treatment was also evaluated. Failure was defined as the persistence of intracranial hypertension despite two successive infusions of the same osmotic agent. The mean number of osmotic solute infusions was 3.7 +/- 5.3 in the mannitol group and 3.3 +/- 4.1 in the hypertonic saline solution group (not significant). The mean number (6.9 +/- 5.6 vs. 13.3 +/- 14.6 episodes) of intracranial hypertension episodes per day and the daily duration (67 +/- 85 vs. 131 +/- 123 min) of intracranial hypertension episodes were significantly lower in the hypertonic saline solution group (p <.01). The rate of clinical failure was also significantly lower in the hypertonic saline solution group: 1 of 10 patients vs. 7 of 10 patients (p <.01).

CONCLUSION

In this study, when a hypertonic solute was required for the treatment of refractory intracranial hypertension episodes in patients with severe head trauma, increasing the osmotic load by giving 2 mL/kg (body weight) of 7.5% saline (361 +/- 13 mOsm) was more effective than giving 2 mL/kg (body weight) of 20% mannitol (175 +/- 12 mOsm). Within the limitations of the present study, these data suggest that giving 2 mL/kg hypertonic saline solution (approximately 480 mOsm/70 kg body weight) is an effective and safe initial treatment for intracranial hypertension episodes in head-trauma patients when osmotherapy is indicated.

[Anaesthesia for patients with intracranial hypertension due to cerebral oedema]

The main objective for anaesthesia in patients with intracranial hypertension (ICH) is to maintain the cerebral perfusion pressure (CPP). Before the operation, the assessment of the level of intracranial pressure relies on the Glasgow coma score and the signs of ICH on the CT-scan. In the perioperative period, repeated transcranial Doppler examinations may help in determining the adequate CPP. Haemodynamic and respiratory complications are common after subarachnoid haemorrhage or head injury. Careful preoperative screening of the cardiovascular and respiratory system is mandatory before anaesthesia. There is no recommended anaesthetic technique for patients with ICH. Nitrous oxide should be avoided in patients with severe ICH or during emergency surgery. Theoretically, intravenous anaesthesia is a better choice than inhalation anesthesia because of the cerebral vasodilatation induced by inhalation agents. In the most severe cases thiopental is the only anaesthetic agent to consider. Treatment of hypovolaemia with fluid loading and the early use of vasoactive agents can be recommended to maintain CPP. Before intracranial surgery, large doses of mannitol have been demonstrated to improve neurological recovery in brain injured patients. The urinary losses due to the infusion of mannitol should be replaced with isotonic saline. Emergence and extubation are best performed in the intensive care unit under close systemic and cerebral haemodynamic control.

Critical care management of head trauma in children

Trauma is the leading cause of both morbidity and mortality in the pediatric population, and traumatic injury causes > 50% of all childhood deaths. Significant mortality rates have been reported for children with traumatic brain injury. Although children have better survival rates as compared with adults with traumatic brain injury, the long-term sequelae and consequences are often more devastating in children due to their age and developmental potential. The costs involved in the care of a child with severe traumatic brain injury, extended over that child's lifetime, are significant. It is unfortunate that despite preventive measures, traumatic brain injury remains the major morbidity and mortality factor for children.