Brain tissue oxygen tension and its response to physiological manipulations: influence of distance from injury site in a swine model of traumatic brain injury.

OBJECTIVE The optimal site for placement of tissue oxygen probes following traumatic brain injury (TBI) remains unresolved. The authors used a previously described swine model of focal TBI and studied brain tissue oxygen tension (PO) at the sites of contusion, proximal and distal to contusion, and in the contralateral hemisphere to determine the effect of probe location on PO and to assess the effects of physiological interventions on PO at these different sites. METHODS A controlled cortical impact device was used to generate a focal lesion in the right frontal lobe in 12 anesthetized swine.

Finding the sweet spot: identification of optimal glucose levels in critically injured patients.

Background: Conflicting data exist regarding optimal glycemic control in critically ill trauma patients. We therefore compared glucose parameters and outcomes among three different glycemic control regimens in a single trauma intensive care unit (ICU), hypothesizing that a moderate regimen would yield optimal avoidance of hyper- and hypoglycemia with equivalent outcomes when compared with a more aggressive approach.

Methods: We retrospectively reviewed 1,422 trauma patients with at least 3-day ICU stay and five glucose measurements from May 2001 to January 2010, spanning three nonoverlapping, sequential glucose control protocols: "relaxed," "aggressive," and "moderate.

Identification of complex metabolic states in critically injured patients using bioinformatic cluster analysis.

Introduction: Advances in technology have made extensive monitoring of patient physiology the standard of care in intensive care units (ICUs). While many systems exist to compile these data, there has been no systematic multivariate analysis and categorization across patient physiological data. The sheer volume and complexity of these data make pattern recognition or identification of patient state difficult.

Where do we go from here? Interim analysis to forge ahead in violence prevention.

Background: The severity and disparity of interpersonal violent injury is staggering. Fifty-three per 100,000 African Americans (AA) die of homicide yearly, 20 per 100,000 in Latinos, whereas the rate is 3 per 100,000 in Caucasians. With the ultimate goal of reducing injury recidivism, which now stands at 35% to 50%, we have designed and implemented a hospital-based, case-managed violence prevention program uniquely applicable to trauma centers.

Refining resuscitation strategies using tissue oxygen and perfusion monitoring in critical organ beds.

Background: Muscle tissue oxygen monitoring (PmO2) holds promise as a continuous guide to resuscitation after hemorrhagic shock, but the relationship of muscle tissue oxygen to perfusion has not been described previously. On the other hand, brain tissue oxygen PbrO2 and perfusion as measured by cerebral blood flow (CBF) are already used clinically, especially as guides to vasopressor use in cerebral perfusion targeted therapy in patients with traumatic brain injury. This laboratory study was undertaken to describe the relative contributions of muscle perfusion and arterial oxygen tension (PaO2) to muscle tissue oxygen (PmO2) levels.

The new Licox combined brain tissue oxygen and brain temperature monitor: assessment of in vitro accuracy and clinical experience in severe traumatic brain injury.

Objective: Monitoring of brain tissue oxygen tension is increasingly being used to monitor patients after severe traumatic brain injury and to guide therapies aimed at maintaining brain tissue oxygen tension above threshold levels. The new Licox PMO combined oxygen and temperature catheter (Integra LifeSciences, Plainsboro, NJ) combines measurements of oxygen tension and temperature in a single probe inserted through a bolt mechanism. In this study, we sought to evaluate the accuracy of the new Licox PMO probe under controlled laboratory conditions and to assess the accuracy of oxygen tension and temperature measurements and the new automated card calibration system.

Brain tissue oxygen tension is more indicative of oxygen diffusion than oxygen delivery and metabolism in patients with traumatic brain injury.

Objectives: Despite the growing clinical use of brain tissue oxygen monitoring, the specific determinants of low brain tissue oxygen tension (P(bt)O2) following severe traumatic brain injury (TBI) remain poorly defined. The objective of this study was to evaluate whether P(bt)O2 more closely reflects variables related to cerebral oxygen diffusion or reflects cerebral oxygen delivery and metabolism.

Design: Prospective observational study.

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.

Use of hemoglobin-based oxygen-carrying solution-201 to improve resuscitation parameters and prevent secondary brain injury in a swine model of traumatic brain injury and hemorrhage: laboratory investigation.

Object: Traumatic brain injury (TBI) often occurs as part of a multisystem trauma that may lead to hemorrhagic shock. Effective resuscitation and restoration of oxygen delivery to the brain is important in patients with TBI because hypotension and hypoxia are associated with poor outcome in head injury. We studied the effects of hemoglobin-based oxygen-carrying (HBOC)-201 solution compared with lactated Ringer (LR) solution in a large animal model of brain injury and hemorrhage, in a blinded prospective randomized study.

The role of lung function in brain tissue oxygenation following traumatic brain injury.

Objective: Previous studies have demonstrated that periods of low brain tissue oxygen tension (PbtO2) are associated with poor outcome after head trauma but have primarily focused on cerebral and hemodynamic factors as causes of low PbtO2. The purpose of this study was to investigate the influence of lung function on PbtO2 with an oxygen challenge (increase in fraction of inspired oxygen [FiO2] concentration to 1.0).

In vitro comparison of two generations of Licox and Neurotrend catheters.

Background: Clinical reports on brain tissue oxygen tension differ in suggested threshold values for defining cerebral ischemia using the Licox and Neurotrend/Paratrend system. We evaluated in vitro performance of both first and second generation devices.

Materials And Methods: Response rate and accuracy in solutions with oxygen tensions from 0 to 150 mm Hg were measured.

New approaches to physiological informatics in neurocritical care.

Introduction: A fundamental purpose of neurocritical care is the management of secondary brain injury. This is often accomplished by monitoring and managing individual patient parameters including physiological vital signs. Yet, the ability to record physiological data exceeds our ability to fully integrate it into patient care.

Continuous muscle tissue oxygenation in critically injured patients: a prospective observational study.

Background: Despite normalization of vital signs, critically injured patients may remain in a state of occult underresuscitation that sets the stage for sepsis, organ failure, and death. A continuous, sensitive, and accurate measure of resuscitation after injury remains elusive.

Methods: In this pilot study, we evaluated the ability of two continuous measures of peripheral tissue oxygenation in their ability to detect hypoperfusion: the Licox polarographic tissue oxygen monitor (PmO2) and the InSpectra near-infrared spectrometer (StO2).

Controlled cortical impact in swine: pathophysiology and biomechanics.

Investigations of the basic pathological, cellular, and molecular mechanisms of traumatic brain injury (TBI) over the past two decades have been carried out primarily in rodents. Unfortunately, these studies have not translated into improved outcome in patients with TBI. To better model human TBI, a swine model of controlled cortical impact (CCI) was developed.

Recovery at one year following isolated traumatic brain injury: a Western Trauma Association prospective multicenter trial.

Background: Age has been shown to be a primary determinant of survival following isolated traumatic brain injury (TBI). We have previously reported that patients > or =65 years who survived mild TBI have decreased functional outcome at 6 months compared with younger patients. The purpose of this study was to further investigate the effect of age on outcome at 1 year in all patients surviving isolated TBI.

Brain tissue oxygen monitoring in intracerebral hemorrhage.

Introduction: Brain tissue oxygen (PbrO2) monitoring is an emerging technique for detection of secondary brain injury in neurocritical care. Although it has been extensively reported in traumatic brain injury and aneurysmal subarachnoid hemorrhage, its use in nontraumatic intracerebral hemorrhage (ICH) has not been well described. We report complementary preliminary studies in a large animal model and in patients that demonstrate the feasibility of PbrO2 monitoring after ICH.

Effects of 23.4% sodium chloride solution in reducing intracranial pressure in patients with traumatic brain injury: a preliminary study.

Objective: Mannitol is the standard of care for patients with increased intracranial pressure (ICP), but multiple administrations of mannitol risk renal toxicity and fluid accumulation in the brain parenchyma with consequent worsening of cerebral edema. This preliminary study assessed the safety and efficacy of small-volume injections of 23.4% sodium chloride solution for the treatment of intracranial hypertension in patients with traumatic brain injury who became tolerant to mannitol.

Serum levels of Hsp60 correlate with the development of acute lung injury after trauma.

Background: Previous studies have shown that heat shock protein 60 (Hsp60) is a danger signal for the immune system and appears to be a key endogenous inflammatory mediator that activates the toll-like receptors and causes the release of proinflammatory cytokines and nitric oxide by immune competent cells, but no data are available for trauma patients. The purpose of this study was to determine whether Hsp60 could be detected in the serum of patients early after severe trauma and whether its serum level might correlate with the development of acute lung injury (ALI) in trauma patients.

Methods: Clinical data were collected prospectively during a 12-month period for trauma patients who were ventilated mechanically for more than 24 h and who met the following inclusion criteria: Injury Severity Score > or =16, age >18 years.

Relationship between brain tissue oxygen tension and CT perfusion: feasibility and initial results.

Background And Purpose: Monitoring of intraparenchymal brain tissue oxygen tension (P(br)O(2)) is an emerging tool in neurocritical care. The purpose of this study was to determine if there is a relationship between CT perfusion (CTP) imaging parameters and P(br)O(2).

Methods: Nineteen patients underwent continuous P(br)O(2) monitoring with probes placed to target white matter in the cerebral hemisphere.

Influence of data resolution and interpolation method on assessment of secondary brain insults in neurocritical care.

Continuous monitoring of physiologic vital signs is routine in neurocritical care. However, this patient information is usually only recorded intermittently (most often hourly) in the medical record. It is unclear whether this is sufficient to represent the occurrence of secondary brain insults (SBIs) or whether more frequent data collection will provide more comprehensive information for patient care.

Posttraumatic stress symptoms in children after mild to moderate pediatric trauma: a longitudinal examination of symptom prevalence, correlates, and parent-child symptom reporting.

Background: Full recovery from injury may be hindered by both physical ailments and psychologic distress. Little information is available on the psychologic response of children to physical trauma, although long-term dysfunction may result if psychologic needs are not identified and addressed. This study examined the prevalence and correlates of posttraumatic stress disorder (PTSD) symptoms in children and adolescents after an acute traumatic event resulting in mild to moderate physical injury.

A novel method of evaluating the impact of secondary brain insults on functional outcomes in traumatic brain-injured patients.

Objectives: Prior studies suggest that the emergency department (ED) occurrence of secondary brain insults (SBIs), such as systemic hypotension and hypoxia, worsens outcome in patients with traumatic brain injury. However, previous methods of assessing SBIs have been relatively crude, generally only determining the incidence and duration of events. The authors hypothesized that a new method that accounts for the cumulative depth and duration of SBIs would provide a more informative measure that better correlates with outcome.

Profile of mothers at risk: an analysis of injury and pregnancy loss in 1,195 trauma patients.

Background: Trauma is the number one cause of maternal death during pregnancy, but incidence of fetal loss exceeds maternal loss by more than 3 to 1. We hypothesized that we could identify women at risk for injury during pregnancy and focus our prevention efforts.

Study Design: Women of childbearing age in the American College of Surgeon's National Trauma Data Bank served as the study population.

Acute respiratory distress syndrome criteria in trauma patients: why the definitions do not work.

Background: The international consensus definitions for acute respiratory distress syndrome (ARDS) have formed the basis for recruitment into randomized, controlled trials and, more recently, standardized the protocols for ventilatory treatment of acute lung injury. Although possibly appropriate for sepsis-induced ARDS, these criteria may not be appropriate for posttraumatic ARDS if the disease patterns are widely divergent. This study tests the hypothesis that standard ARDS criteria applied to the trauma population will capture widely disparate forms of acute lung injury and are too nonspecific to identify a population at risk for prolonged respiratory failure and associated complications.