Worldwide Organization of Neurocritical Care: Results from the PRINCE Study Part 1.

INTRODUCTION: Neurocritical care focuses on the care of critically ill patients with an acute neurologic disorder and has grown significantly in the past few years. However, there is a lack of data that describe the scope of practice of neurointensivists and epidemiological data on the types of patients and treatments used in neurocritical care units worldwide. To address these issues, we designed a multicenter, international, point-prevalence, cross-sectional, prospective, observational, non-interventional study in the setting of neurocritical care (PRINCE Study). METHODS: In this manuscript, we analyzed data from the initial phase of the study that included registration, hospital, and intensive care unit (ICU) organizations. We present here descriptive statistics to summarize data from the registration case report form. We performed the Kruskal-Wallis test followed by the Dunn procedure to test for differences in practices among world regions. RESULTS: We analyzed information submitted by 257 participating sites from 47 countries. The majority of those sites, 119 (46.3%), were in North America, 44 (17.2%) in Europe, 34 (13.3%) in Asia, 9 (3.5%) in the Middle East, 34 (13.3%) in Latin America, and 14 (5.5%) in Oceania. Most ICUs are from academic institutions (73.4%) located in large urban centers (44% > 1 million inhabitants). We found significant differences in hospital and ICU organization, resource allocation, and use of patient management protocols. The highest nursing/patient ratio was in Oceania (100% 1:1). Dedicated Advanced Practiced Providers are mostly present in North America (73.7%) and are uncommon in Oceania (7.7%) and the Middle East (0%). The presence of dedicated respiratory therapist is common in North America (85%), Middle East (85%), and Latin America (84%) but less common in Europe (26%) and Oceania (7.7%). The presence of dedicated pharmacist is highest in North America (89%) and Oceania (85%) and least common in Latin America (38%). The majority of respondents reported having a dedicated neuro-ICU (67% overall; highest in North America: 82%; and lowest in Oceania: 14%). CONCLUSION: The PRINCE Study results suggest that there is significant variability in the delivery of neurocritical care. The study also shows it is feasible to undertake international collaborations to gather global data about the practice of neurocritical care.

Global Survey of Outcomes of Neurocritical Care Patients: Analysis of the PRINCE Study Part 2.

BACKGROUND: Neurocritical care is devoted to the care of critically ill patients with acute neurological or neurosurgical emergencies. There is limited information regarding epidemiological data, disease characteristics, variability of clinical care, and in-hospital mortality of neurocritically ill patients worldwide. We addressed these issues in the Point PRevalence In Neurocritical CarE (PRINCE) study, a prospective, cross-sectional, observational study. METHODS: We recruited patients from various intensive care units (ICUs) admitted on a pre-specified date, and the investigators recorded specific clinical care activities they performed on the subjects during their first 7 days of admission or discharge (whichever came first) from their ICUs and at hospital discharge. In this manuscript, we analyzed the final data set of the study that included patient admission characteristics, disease type and severity, ICU resources, ICU and hospital length of stay, and in-hospital mortality. We present descriptive statistics to summarize data from the case report form. We tested differences between geographically grouped data using parametric and nonparametric testing as appropriate. We used a multivariable logistic regression model to evaluate factors associated with in-hospital mortality. RESULTS: We analyzed data from 1545 patients admitted to 147 participating sites from 31 countries of which most were from North America (69%, N = 1063). Globally, there was variability in patient characteristics, admission diagnosis, ICU treatment team and resource allocation, and in-hospital mortality. Seventy-three percent of the participating centers were academic, and the most common admitting diagnosis was subarachnoid hemorrhage (13%). The majority of patients were male (59%), a half of whom had at least two comorbidities, and median Glasgow Coma Scale (GCS) of 13. Factors associated with in-hospital mortality included age (OR 1.03; 95% CI, 1.02 to 1.04); lower GCS (OR 1.20; 95% CI, 1.14 to 1.16 for every point reduction in GCS); pupillary reactivity (OR 1.8; 95% CI, 1.09 to 3.23 for bilateral unreactive pupils); admission source (emergency room versus direct admission [OR 2.2; 95% CI, 1.3 to 3.75]; admission from a general ward versus direct admission [OR 5.85; 95% CI, 2.75 to 12.45; and admission from another ICU versus direct admission [OR 3.34; 95% CI, 1.27 to 8.8]); and the absence of a dedicated neurocritical care unit (NCCU) (OR 1.7; 95% CI, 1.04 to 2.47). CONCLUSION: PRINCE is the first study to evaluate care patterns of neurocritical patients worldwide. The data suggest that there is a wide variability in clinical care resources and patient characteristics. Neurological severity of illness and the absence of a dedicated NCCU are independent predictors of in-patient mortality.

The Safety of Multimodality Monitoring Using a Triple-Lumen Bolt in Severe Acute Brain Injury.

BACKGROUND: Multimodality monitoring is used frequently to guide care of patients with severe acute brain injury. The aim of this study was to examine the safety and reliability of multimodality monitoring. METHODS: From a prospective observational database at a Level I trauma center, 501 patients, including 300 men and 201 women (mean age 58 ± 39 years) were identified retrospectively. Each patient received a triple-lumen bolt and 3 monitors: intracranial pressure, brain temperature, and brain oxygen. Intensive care unit and hospital records were examined to identify complications, reasons for device replacement, malfunction and infection. Head computed tomography (CT) scans performed before and after the monitors were inserted were examined for evidence of monitor-related adverse effects. RESULTS: A total of 696 triple-lumen bolts were placed. Median duration of monitoring was 78.88 hours (interquartile range, 33.0-133.2 hours). Bilateral monitors were inserted in 22 (3.16%) patients. Ten (1.43%) monitors were replaced to allow magnetic resonance imaging, and 40 (5.74%) monitors were replaced to facilitate additional cranial surgery. Of 35 (5.02%) monitors that were replaced because they were thought to not be functioning properly, 19 (54.29%) were subsequently found to be functioning normally. Follow-up CT scans were compared with CT scans obtained before insertion of monitors; 9 (2.13%) small contusions and 10 (2.36%) extra-axial hematomas associated with the devices were identified. Based on the CT findings, the hematomas were thought to be associated with the insertion technique rather than the device; 4 hematomas required treatment. Twenty-two (3.16%) devices were incorrectly placed (e.g., the probe was in an infarct or an already existing contusion). Only 1 associated infection was identified. CONCLUSIONS: Placement of intracranial monitors for multimodality neuromonitoring using a triple-lumen bolt appears to be safe. The complication rate is similar to published complication rates for single-lumen bolts and single monitors.

Common Data Elements for Unruptured Intracranial Aneurysms and Subarachnoid Hemorrhage Clinical Research: A National Institute for Neurological Disorders and Stroke and National Library of Medicine Project.

OBJECTIVES: The goal for this project was to develop a comprehensive set of common data elements (CDEs), data definitions, case report forms and guidelines for use in unruptured intracranial aneurysm (UIA) and subarachnoid hemorrhage (SAH) clinical research, as part of a new joint effort between the National Institute of Neurological Disorders and Stroke (NINDS) and the National Library of Medicine of the US National Institutes of Health. These UIA and SAH CDEs will join several other neurological disease-specific CDEs that have already been developed and are available for use by research investigators. METHODS: A Working Group (WG) divided into eight sub-groups and a Steering Committee comprised of international UIA and SAH experts reviewed existing NINDS CDEs and instruments, created new elements when needed and provided recommendations for UIA and SAH clinical research. The recommendations were compiled, internally reviewed by the entire UIA and SAH WG and posted online for 6 weeks for external public comments. The UIA and SAH WG and the NINDS CDE team reviewed the final version before posting the SAH Version 1.0 CDE recommendations. RESULTS: The NINDS UIA and SAH CDEs and supporting documents are publicly available on the NINDS CDE ( https://www.commondataelements.ninds.nih.gov/#page=Default ) and NIH Repository ( https://cde.nlm.nih.gov/home ) websites. The recommendations are organized into domains including Participant Characteristics and Outcomes and Endpoints. CONCLUSION: Dissemination and widespread use of CDEs can facilitate UIA and SAH clinical research and clinical trial design, data sharing, and analyses of observational retrospective and prospective data. It is vital to maintain an international and multidisciplinary collaboration to ensure that these CDEs are implemented and updated when new information becomes available.

Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase-II: A Phase II Randomized Trial.

OBJECTIVES: A relationship between reduced brain tissue oxygenation and poor outcome following severe traumatic brain injury has been reported in observational studies. We designed a Phase II trial to assess whether a neurocritical care management protocol could improve brain tissue oxygenation levels in patients with severe traumatic brain injury and the feasibility of a Phase III efficacy study. DESIGN: Randomized prospective clinical trial. SETTING: Ten ICUs in the United States. PATIENTS: One hundred nineteen severe traumatic brain injury patients. INTERVENTIONS: Patients were randomized to treatment protocol based on intracranial pressure plus brain tissue oxygenation monitoring versus intracranial pressure monitoring alone. Brain tissue oxygenation data were recorded in the intracranial pressure -only group in blinded fashion. Tiered interventions in each arm were specified and impact on intracranial pressure and brain tissue oxygenation measured. Monitors were removed if values were normal for 48 hours consecutively, or after 5 days. Outcome was measured at 6 months using the Glasgow Outcome Scale-Extended. MEASUREMENTS AND MAIN RESULTS: A management protocol based on brain tissue oxygenation and intracranial pressure monitoring reduced the proportion of time with brain tissue hypoxia after severe traumatic brain injury (0.45 in intracranial pressure-only group and 0.16 in intracranial pressure plus brain tissue oxygenation group; p < 0.0001). Intracranial pressure control was similar in both groups. Safety and feasibility of the tiered treatment protocol were confirmed. There were no procedure-related complications. Treatment of secondary injury after severe traumatic brain injury based on brain tissue oxygenation and intracranial pressure values was consistent with reduced mortality and increased proportions of patients with good recovery compared with intracranial pressure-only management; however, the study was not powered for clinical efficacy. CONCLUSIONS: Management of severe traumatic brain injury informed by multimodal intracranial pressure and brain tissue oxygenation monitoring reduced brain tissue hypoxia with a trend toward lower mortality and more favorable outcomes than intracranial pressure-only treatment. A Phase III randomized trial to assess impact on neurologic outcome of intracranial pressure plus brain tissue oxygenation-directed treatment of severe traumatic brain injury is warranted.

"Bloodless" Neurosurgery Among Jehovah's Witnesses: A Comparison with Matched Concurrent Controls.

BACKGROUND: Jehovah's Witnesses (JW) are a Christian faith with >1 million members in the United States who do not accept autologous blood transfusions. The optimal management of these patients undergoing neurosurgical procedures is not well defined. Here, we examined the feasibility and safety of JW undergoing neurosurgery in a blood management program. STUDY DESIGN AND METHODS: Sixty-eight JW patients including 23 men and 45 women (mean age 53 ± 12 years) who underwent a variety of cranial (n = 19) and spinal (n = 49) neurosurgical procedures during a 5-year period were identified retrospectively and their hospital charts, anesthetic records, and operative reports reviewed. A concurrent cohort of sex-, age-, and procedure-matched non-JW controls also was identified. RESULTS: Among JW patients, a cell-saving system was used in 27 cases, with blood retransfused in 13 cases. Lactated Ringers solution was used extensively intraoperatively; albumin was given to 15 patients. The median decrease in hemoglobin was 2.1 g/dL. One patient had a postoperative hemoglobin value <7 g/dL. One patient returned to the operating room to revise a lumbar pedicle screw, and one patient had postoperative seizures. No cardiopulmonary complications, sepsis, pneumonia, or wound infection were observed. Compared with the matched control group, similar outcome results were observed. Blood loss and operative time also were similar in JW patients and controls. CONCLUSIONS: Neurosurgical procedures in Jehovah's Witnesses are feasible, safe, and have similar outcomes to patients willing to accept transfusion when managed within a multidisciplinary blood-management program.

Alternative clinical trial design in neurocritical care.

Neurocritical care involves the care of highly complex patients with combinations of physiologic derangements in the brain and in extracranial organs. The level of evidence underpinning treatment recommendations remains low due to a multitude of reasons including an incomplete understanding of the involved physiology; lack of good quality, prospective, standardized data; and the limited success of conventional randomized controlled trials. Comparative effectiveness research can provide alternative perspectives and methods to enhance knowledge and evidence within the field of neurocritical care; these include large international collaborations for generation and maintenance of high quality data, statistical methods that incorporate heterogeneity and individualize outcome prediction, and finally advanced bioinformatics that integrate large amounts of variable-source data into patient-specific phenotypes and trajectories.

Multi-modality neuro-monitoring: conventional clinical trial design.

Multi-modal monitoring has become an integral part of neurointensive care. However, our approach is at this time neither standardized nor backed by data from randomized controlled trials. The goal of the second Neurocritical Care Research Conference was to discuss research priorities in multi-modal monitoring, what research tools are available, as well as the latest advances in clinical trial design. This section of the meeting was focused on how such a trial should be designed so as to maximize yield and avoid mistakes of the past.

Regional brain monitoring in the neurocritical care unit.

Regional multimodality monitoring has evolved over the last several years as a tool to understand the mechanisms of brain injury and brain function at the cellular level. Multimodality monitoring offers an important augmentation to the clinical exam and is especially useful in comatose neurocritical care patients. Cerebral microdialysis, brain tissue oxygen monitoring, and cerebral blood flow monitoring all offer insight into permutations in brain chemistry and function that occur in the context of brain injury. These tools may allow for development of individual therapeutic strategies that are mechanistically driven and goal-directed. We present a summary of the discussions that took place during the Second Neurocritical Care Research Conference regarding regional brain monitoring.

Global monitoring in the neurocritical care unit.

Effective methods of monitoring the status of patients with neurological injuries began with non-invasive observations and evolved during the past several decades to include more invasive monitoring tools and physiologic measures. The monitoring paradigm continues to evolve, this time back toward the use of less invasive tools. In parallel, the science of monitoring began with the global assessment of the patient's neurological condition, evolved to focus on regional monitoring techniques, and with the advent of enhanced computing capabilities is now moving back to focus on global monitoring. The purpose of this session of the Second Neurocritical Care Research Conference was to collaboratively develop a comprehensive understanding of the state of the science for global brain monitoring and to identify research priorities for intracranial pressure monitoring, neuroimaging, and neuro-electrophysiology monitoring.

Human albumin administration in subarachnoid hemorrhage: results of an international survey.

BACKGROUND: Subarachnoid hemorrhage (SAH) is a devastating disease. Nimodipine is the only medical treatment shown to improve outcome of SAH patients. Human albumin (ALB) may exert neuroprotection in SAH. However, current usage of ALB in SAH is not known. We conducted an international survey of clinicians involved in the care of SAH patients to determine current practice of ALB administration in SAH. METHODS: We constructed a 27-question survey. Our sampling frame consisted of neurointensivists, general intensivists, neurocritical care nurses, critical care pharmacists, and neurosurgeons. The survey was available from 11/15/2012 to 12/15/2012. We performed mostly descriptive statistical analysis. RESULTS: We obtained 362 responses from a diverse range of world regions. Most respondents were intensivist physicians (88 %), who worked in academic institutions (73.5 %) with a bed capacity >500 (64.1 %) and an established institutional management protocol for SAH patients (70.2 %). Most respondents (83.5 %) indicated that their institutions do not incorporate ALB in their protocol, but half of them (45.9 %) indicated using ALB outside it. ALB administration is influenced by several factors: geographic variation (more common among US respondents); institutions with a dedicated neuroICU; and availability of SAH management protocol. Most respondents (75 %) indicated that a clinical trial to test the efficacy of ALB in SAH is needed. CONCLUSIONS: In this survey we found that ALB administration in SAH patients is common and influenced by several factors. Majority of respondents support a randomized clinical trial to determine the safety and efficacy of ALB administration in SAH patients.

Response of brain oxygen to therapy correlates with long-term outcome after subarachnoid hemorrhage.

BACKGROUND: Brain oxygen (PbtO2) monitoring can help guide care of poor-grade aneurysmal subarachnoid hemorrhage (aSAH) patients. The relationship between PbtO2-directed therapy and long-term outcome is unclear. We hypothesized that responsiveness to PbtO2-directed interventions is associated with outcome. METHODS: Seventy-six aSAH patients who underwent PbtO2 monitoring were included. Long-term outcome [Glasgow Outcome Score-Extended (GOS-E) and modified Rankin Scale (mRS)] was ascertained using the social security death database and structured telephone interviews. Univariate and multivariate regression were used to identify variables that correlated with outcome. RESULTS: Data from 64 patients were analyzed (12 were lost to follow-up). There were 530 episodes of compromised PbtO2 (<20 mmHg) during a total of 7,174 h of monitor time treated with 1,052 interventions. Forty-two patients (66 %) survived to discharge. Median follow-up was 8.5 months (range 0.1-87). At most recent follow-up 35 (55 %) patients were alive, and 28 (44 %) had a favorable outcome (mRS ≤3). In multivariate ordinal regression analysis, only age and response to PbtO2-directed intervention correlated significantly with outcome. Increased age was associated with worse outcome (coeff. 0.8, 95 % CI 0.3-1.3, p = 0.003), and response to PbtO2-directed intervention was associated with improved outcome (coeff. -2.12, 95 % CI -4.0 to -0.26, p = 0.03). Patients with favorable outcomes had a 70 % mean rate of response to PbtO2-directed interventions whereas patients with poor outcomes had a 45 % response rate (p = 0.005). CONCLUSIONS: Response to PbtO2-directed intervention is associated with improved long-term functional outcome in aSAH patients.

Brief report: a comparison of clinical and research practices in measuring cerebral perfusion pressure: a literature review and practitioner survey.

BACKGROUND: Our objective was to determine whether there is variability in the foundational literature and across centers in how mean arterial blood pressure is measured to calculate cerebral perfusion pressure. METHODS: We reviewed foundational literature and sent an e-mail survey to members of the Neurocritical Care Society. RESULTS: Of 32 articles reporting cerebral perfusion pressure data, the reference point for mean arterial blood pressure was identified in 16: 10 heart and 6 midbrain. The overall survey response rate was 14.3%. Responses from 31 of 34 (91%) United Council for Neurologic Subspecialties fellowship-accredited Neurointensive Care Units indicated the reference point was most often the heart (74%), followed by the midbrain (16%). Conflicting answers were received from 10%. CONCLUSIONS: There is substantive heterogeneity in both research reports and clinical practice in how mean arterial blood pressure is measured to determine cerebral perfusion pressure.

Brain lactate metabolism in humans with subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Lactate is central for the regulation of brain metabolism and is an alternative substrate to glucose after injury. Brain lactate metabolism in patients with subarachnoid hemorrhage has not been fully elucidated. METHODS: Thirty-one subarachnoid hemorrhage patients monitored with cerebral microdialysis (CMD) and brain oxygen (PbtO(2)) were studied. Samples with elevated CMD lactate (>4 mmol/L) were matched to PbtO(2) and CMD pyruvate and categorized as hypoxic (PbtO(2) <20 mm Hg) versus nonhypoxic and hyperglycolytic (CMD pyruvate >119 µmol/L) versus nonhyperglycolytic. RESULTS: Median per patient samples with elevated CMD lactate was 54% (interquartile range, 11%-80%). Lactate elevations were more often attributable to cerebral hyperglycolysis (78%; interquartile range, 5%-98%) than brain hypoxia (11%; interquartile range, 4%-75%). Mortality was associated with increased percentage of samples with elevated lactate and brain hypoxia (28% [interquartile range 9%-95%] in nonsurvivors versus 9% [interquartile range 3%-17%] in survivors; P=0.02) and lower percentage of elevated lactate and cerebral hyperglycolysis (13% [interquartile range, 1%-87%] versus 88% [interquartile range, 27%-99%]; P=0.07). Cerebral hyperglycolytic lactate production predicted good 6-month outcome (odds ratio for modified Rankin Scale score, 0-3 1.49; CI, 1.08-2.05; P=0.016), whereas increased lactate with brain hypoxia was associated with a reduced likelihood of good outcome (OR, 0.78; CI, 0.59-1.03; P=0.08). CONCLUSIONS: Brain lactate is frequently elevated in subarachnoid hemorrhage patients, predominantly because of hyperglycolysis rather than hypoxia. A pattern of increased cerebral hyperglycolytic lactate was associated with good long-term recovery. Our data suggest that lactate may be used as an aerobic substrate by the injured human brain.

Detection of cerebral compromise with multimodality monitoring in patients with subarachnoid hemorrhage.

BACKGROUND: Studies in traumatic brain injury suggest that monitoring techniques such as brain tissue oxygen (P(BTO2)) and cerebral microdialysis may complement conventional intracranial pressure (ICP) and cerebral perfusion pressure (CPP) measurements. OBJECTIVE: In this study of poor-grade (Hunt and Hess grade IV and V) subarachnoid hemorrhage (SAH) patients, we examined the prevalence of brain hypoxia and brain energy dysfunction in the presence of normal and abnormal ICP and CPP. METHODS: SAH patients who underwent multimodal neuromonitoring and cerebral microdialysis were studied. We examined the frequency of brain hypoxia and energy dysfunction in different ICP and CPP ranges and the relationship between P(BTO2) and the lactate/pyruvate ratio (LPR). RESULTS: A total of 2394 samples from 19 patients were analyzed. There were 149 samples with severe brain hypoxia (P(BTO2) ≤10 mm Hg) and 347 samples with brain energy dysfunction (LPR >40). The sensitivities of abnormal ICP or CPP for elevated LPR and reduced P(BTO2) were poor (21.2% at best), and the LPR or P(BTO2) was abnormal in many instances when ICP or CPP was normal. Severe brain hypoxia was often associated with an LPR greater than 40 (86% of samples). In contrast, mild brain hypoxia (≤20 mm Hg) and severe brain hypoxia were observed in only 53% and 36% of samples with brain energy dysfunction, respectively. CONCLUSION: Our data demonstrate that ICP and CPP monitoring may not always detect episodes of cerebral compromise in SAH patients. Our data suggest that several complementary monitors may be needed to optimize the care of poor-grade SAH patients.

Brain hypoxia is associated with short-term outcome after severe traumatic brain injury independently of intracranial hypertension and low cerebral perfusion pressure.

BACKGROUND: Brain hypoxia (BH) can aggravate outcome after severe traumatic brain injury (TBI). Whether BH or reduced brain oxygen (Pbto(2)) is an independent outcome predictor or a marker of disease severity is not fully elucidated. OBJECTIVE: To analyze the relationship between Pbto(2), intracranial pressure (ICP), and cerebral perfusion pressure (CPP) and to examine whether BH correlates with worse outcome independently of ICP and CPP. METHODS: We studied 103 patients monitored with ICP and Pbto(2) for > 24 hours. Durations of BH (Pbto(2) < 15 mm Hg), ICP > 20 mm Hg, and CPP < 60 mm Hg were calculated with linear interpolation, and their associations with outcome within 30 days were analyzed. RESULTS: Duration of BH was longer in patients with unfavorable (Glasgow Outcome Scale score, 1-3) than in those with favorable (Glasgow Outcome Scale, 4-5) outcome (8.3 ± 15.9 vs 1.7 ± 3.7 hours; P < .01). In patients with intracranial hypertension, those with BH had fewer favorable outcomes (46%) than those without (81%; P < .01); similarly, patients with low CPP and BH were less likely to have favorable outcome than those with low CPP but normal Pbto(2) (39% vs 83%; P < .01). After ICP, CPP, age, Glasgow Coma Scale score, Marshall computed tomography grade, and Acute Physiology and Chronic Health Evaluation II score were controlled for, BH was independently associated with poor prognosis (adjusted odds ratio for favorable outcome, 0.89 per hour of BH; 95% confidence interval, 0.79-0.99; P = .04). CONCLUSION: Brain hypoxia is associated with poor short-term outcome after severe traumatic brain injury independently of elevated ICP, low CPP, and injury severity. Pbto(2) may be an important therapeutic target after severe traumatic brain injury.

Reduced brain tissue oxygen in traumatic brain injury: are most commonly used interventions successful?

BACKGROUND: Brain tissue oxygenation (PbtO2)-guided management facilitates treatment of reduced PbtO2 episodes potentially conferring survival and outcome advantages in severe traumatic brain injury (TBI). To date, the nature and effectiveness of commonly used interventions in correcting compromised PbtO2 in TBI remains unclear. We sought to identify the most common interventions used in episodes of compromised PbtO2 and to analyze which were effective. METHODS: A retrospective 7-year review of consecutive severe TBI patients with a PbtO2 monitor was conducted in a Level I trauma center's intensive care unit or neurosurgical registry. Episodes of compromised PbtO2 (defined as <20 mm Hg for 0.25-4 hours) were identified, and clinical interventions conducted during these episodes were analyzed. Response to treatment was gauged on how rapidly (ΔT) PbtO2 normalized (>20 mm Hg) and how great the PbtO2 increase was (ΔPbtO2). Intracranial pressure (ΔICP) and cerebral perfusion pressure (ΔCPP) also were examined for these episodes. RESULTS: Six hundred twenty-five episodes of reduced PbtO2 were identified in 92 patients. Patient characteristics were: age 41.2 years, 77.2% men, and Injury Severity Score and head or neck Abbreviated Injury Scale score of 34.0 ± 9.2 and 4.9 ± 0.4, respectively. Five interventions: narcotics or sedation, pressors, repositioning, FIO2/PEEP increases, and combined sedation or narcotics + pressors were the most commonly used strategies. Increasing the number of interventions resulted in worsening the time to PbtO2 correction. Triple combinations resulted in the lowest ΔICP and dual combinations in the highest ΔCPP (p < 0.05). CONCLUSION: Clinicians use a limited number of interventions when correcting compromised PbtO2. Using strategies employing many interventions administered closely together may be less effective in correcting PbO2, ICP, and CPP deficits. Some PbtO2 deficits may be self-limited.