Clinical outcome of severe head injury using three different ICP and CPP protocol-driven therapies

A novel step-down infusion method of barbiturate therapy: Its safety and effectiveness for intracranial pressure control

Intracranial pressure (ICP) has to be maintained quite constant, because increased ICP caused by cerebrovascular disease and head trauma is fatal. Although controlling ICP is clinically critical, only few therapeutic methods are currently available. Barbiturates, a group of sedative-hypnotic drugs, are recognized as secondary treatment for controlling ICP. We proposed a novel "step-down infusion" method, administrating barbiturate (thiamylal) after different time point from the start of treatment under normothermia, at doses of 3.0 (0-24 h), 2.0 (24-48 h), 1.5 (48-72 h), and 1.0 mg/kg/h (72-96 h), and evaluated its safety and effectiveness in clinical. In 22 patients with severe traumatic brain injury or severe cerebrovascular disease (Glasgow coma scale ≤8), thiamylal concentrations and ICP were monitored. The step-down infusion method under normothermia maintained stable thiamylal concentrations (<26.1 µg/ml) without any abnormal accumulation/elevation, and could successfully keep ICP <20 mmHg (targeted management value: ICP <20 mmHg) in all patients. Moreover the mean value of cerebral perfusion pressure (CPP) was also maintained over 65 mmHg during all time course (targeted management value: CPP >65 mmHg), and no threatening changes in serum potassium or any hemodynamic instability were observed. Our novel "step-down infusion" method under normothermia enabled to maintain stable, safe thiamylal concentrations to ensure both ICP reduction and CPP maintenance without any serious side effects, may provide a novel and clinically effective treatment option for patients with increased ICP.

Role of Intraoperative ICP And CPP Measurement for Predicting Surgical Outcome in Severe Traumatic Brain Injury

Introduction Traumatic brain injury (TBI) is one of the leading causes of mortality and disability worldwide, and optimizing the management of these patients is a continuing challenge. Intraoperative intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were evaluated for use as prognostic indicators after surgery for severe TBI. Although ICP and CPP monitoring is standard postsurgery treatment for TBI, very few studies have reported the use of ICP and CPP values monitored during surgery.

Objectives The objectives of this study were to evaluate the use of intraoperative ICP and CPP values as prognostic indicators and as subjective guidelines for managing severe TBI.

Materials and Methods All patients with severe TBI who underwent surgical decompression and ICP monitoring intraoperatively were included in our study from 2017 to 2018. We measured ICP and CPP values after creation of the first burr hole, after hematoma evacuation, and after wound closure.

Results From the analysis of receiver-operated characteristic (ROC) curves, we observed that ICP initial (cutoff > 28 mm Hg) and CPP initial (cutoff < 44.5 mm Hg) are the best predictors of unfavorable outcomes. Favorable outcome (Glasgow outcome scale [GOS] 4 and 5) and unfavorable outcome (GOS 1–3) after 6 months were achieved in 64.1 and 35.8% of patients, respectively. There was significant difference between the ICP and CPP values which are measured after the first burrhole, after hematoma evacuation, and after scalp closure in both favorable and unfavorable outcomes. The highest positive Pearson’s correlation coefficient is found between GOS and ICP and CPP after first burr hole.

Conclusion Monitoring ICP and CPP during surgery improves management in patients with severe TBI and provides an early prognostic indicator in such patients.

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.

Benefit on optimal cerebral perfusion pressure targeted treatment for traumatic brain injury patients

PURPOSE

The maintenance of patient-specific optimal cerebral perfusion pressure (CPPopt) is crucial for patients with traumatic brain injury (TBI). The goal of the study was to explore the influence of CPP declination from CPPopt value on the TBI patients' outcome.

METHODS

The CPP and cerebrovascular autoregulation (CA) monitoring of 52 TBI patients was performed. Patient-specific CPPopt has been identified and the associations between the patients' outcome and complex influence of time of CPP declination from CPPopt value, age, and the duration of CA impairment episodes has been analyzed.

RESULTS

The multiple correlation coefficient between the Glasgow outcome scale (GOS), duration of CA impairment events and percentage time, when 0<ΔCPPopt<10mmHg was r=-0.643 (P<0.001). The multiple correlation coefficients between GOS, age, and percentage time of ΔCPPopt when 0<ΔCPPopt<10mmHg was r=-0.587 (P<0.001).

CONCLUSION

The CPPopt-targeted patient-specific management might be useful for stabilizing CA in TBI patients as well as for improving their outcome. Better outcomes were obtained by maintaining CPP in light hyperperfusion condition (up to 10mmHg above CPPopt) when CPPopt is in the range of 60-80mmHg, and keeping CPP within the range of CPPopt +/-5mmHg when CPPopt is above 80mmHg.

Pharmacodynamic Analysis of a Fluid Challenge

OBJECTIVE

This study aims to describe the pharmacodynamics of a fluid challenge over a 10-minute period in postoperative patients.

DESIGN

Prospective observational study.

SETTING

General and cardiothoracic ICU, tertiary hospital.

PATIENTS

Twenty-six postoperative patients.

INTERVENTION

Two hundred and fifty-milliliter fluid challenge performed over 5 minutes. Data were recorded over 10 minutes after the end of fluid infusion

MEASUREMENTS AND MAIN RESULTS

Cardiac output was measured with a calibrated LiDCOplus (LiDCO, Cambridge, United Kingdom) and Navigator (Applied Physiology, Sydney, Australia) to obtain the Pmsf analogue (Pmsa). Pharmacodynamics outcomes were modeled using a Bayesian inferential approach and Markov chain Monte Carlo estimation methods. Parameter estimates were summarized as the means of their posterior distributions, and their uncertainty was assessed by the 95% credible intervals. Bayesian probabilities for groups' effect were also derived. The predicted maximal effect on cardiac output was observed at 1.2 minutes (95% credible interval, -0.6 to 2.8 min) in responders. The probability that the estimated area under the curve of central venous pressure was smaller in nonresponders was 0.12. (estimated difference, -4.91 mm Hg·min [95% credible interval, -13.45 to 3.3 mm Hg min]). After 10 minutes, there is no evidence of a difference between groups for any hemodynamic variable.

CONCLUSIONS

The maximal change in cardiac output should be assessed 1 minute after the end of the fluid infusion. The global effect of the fluid challenge on central venous pressure is greater in nonresponders, but not the change observed 10 minutes after the fluid infusion. The effect of a fluid challenge on hemodynamics is dissipated in 10 minutes similarly in both groups.

Physiological complexity of acute traumatic brain injury in patients treated with a brain oxygen protocol: utility of symbolic regression in predictive modeling of a dynamical system

Predictive modeling of emergent behavior, inherent to complex physiological systems, requires the analysis of large complex clinical data streams currently being generated in the intensive care unit. Brain tissue oxygen protocols have yielded outcome benefits in traumatic brain injury (TBI), but the critical physiological thresholds for low brain oxygen have not been established for a dynamical patho-physiological system. High frequency, multi-modal clinical data sets from 29 patients with severe TBI who underwent multi-modality neuro-clinical care monitoring and treatment with a brain oxygen protocol were analyzed. The inter-relationship between acute physiological parameters was determined using symbolic regression (SR) as the computational framework. The mean patient age was 44.4±15 with a mean admission GCS of 6.6±3.9. Sixty-three percent sustained motor vehicle accidents and the most common pathology was intra-cerebral hemorrhage (50%). Hospital discharge mortality was 21%, poor outcome occurred in 24% of patients, and good outcome occurred in 56% of patients. Criticality for low brain oxygen was intracranial pressure (ICP) ≥22.8 mm Hg, for mortality at ICP≥37.1 mm Hg. The upper therapeutic threshold for cerebral perfusion pressure (CPP) was 75 mm Hg. Eubaric hyperoxia significantly impacted partial pressure of oxygen in brain tissue (PbtO2) at all ICP levels. Optimal brain temperature (Tbr) was 34-35°C, with an adverse effect when Tbr≥38°C. Survivors clustered at [Formula: see text] Hg vs. non-survivors [Formula: see text] 18 mm Hg. There were two mortality clusters for ICP: High ICP/low PbtO2 and low ICP/low PbtO2. Survivors maintained PbtO2 at all ranges of mean arterial pressure in contrast to non-survivors. The final SR equation for cerebral oxygenation is: [Formula: see text]. The SR-model of acute TBI advances new physiological thresholds or boundary conditions for acute TBI management: PbtO2≥25 mmHg; ICP≤22 mmHg; CPP≈60-75 mmHg; and Tbr≈34-37°C. SR is congruous with the emerging field of complexity science in the modeling of dynamical physiological systems, especially during pathophysiological states. The SR model of TBI is generalizable to known physical laws. This increase in entropy reduces uncertainty and improves predictive capacity. SR is an appropriate computational framework to enable future smart monitoring devices.

A survey of routine treatment of patients with intracranial hypertension (ICH) in specialized trauma centers in Sao Paulo, Brazil: a 11 million metropole!

OBJECTIVE

A survey of intensive care units (ICU) in São Paulo that care for patients with TBI and ICH using the hyperventilation technique.

METHODS

A questionnaire was given to the physiotherapist coordinator at 57 hospitals in São Paulo, where 24-h neurosurgery service is provided.

RESULTS

Fifty-one (89.5%) hospitals replied. From this total, thirty-four (66.7% perform the hyperventilation technique, 30 (85%) had the objective to reach values below 35 mmHg, four (11%) levels between 35 mmHg and 40 mmHg and one (3%) values over 40 mmHg.

CONCLUSIONS

We concluded that most hospitals in São Paulo perform hyperventilation in patients with severe brain trauma although there are not any specific Brazilian guidelines on this topic. Widespread controversy on the use of the hyperventilation technique in patients with severe brain trauma highlights the need for a specific Global policy on this topic.

Changes in the mean systemic filling pressure during a fluid challenge in postsurgical intensive care patients

PURPOSE

The difference between mean systemic filling (Pmsf) and central venous pressure (CVP) is the venous return gradient (dVR). The aim of this study is to assess the significance of the Pmsf analogue (Pmsa) and the dVR during a fluid challenge.

METHODS

We performed a prospective observational study in postsurgical patients. Patients were monitored with a central venous catheter, a LiDCO™plus and the Navigator™. A 250-ml intravenous fluid challenge was given over 5 min. A positive response to the fluid challenge was defined as either a stroke volume (SV) or cardiac output increase of greater than 10 %.

RESULTS

A total of 101 fluid challenges were observed in 39 patients. In 43 events (42.6 %) the SV and CO increased by more than 10 %. Pmsa increased similarly during a fluid challenge in responders and non-responders (3.1 ± 1.9 vs. 3.1 ± 1.8, p = 0.9), whereas the dVR increased in responders (1.16 ± 0.8 vs. 0.2 ± 1, p < 0.001) as among non-responders CVP increased along with Pmsa (2.9 ± 1.7 vs. 3.1 ± 1.8, p = 0.15). Resistance to venous return did not change immediately after a fluid challenge. Heart performance (Eh) decreased significantly among non-responders (0.41 ± 0.15 vs. 0.34 ± 0.13, p < 0.001) whereas among responders it did not change when compared with baseline value (0.35 ± 0.15 vs. 0.34 ± 0.12, p = 0.15).

CONCLUSIONS

The changes in Pmsa and dVR measured at the bedside during a fluid challenge are consistent with the cardiovascular model described by Guyton.

Effect of acute endotoxemia on analog estimates of mean systemic pressure

Dynamic estimates of mean systemic pressure based on a Guytonian analog model (Pmsa) appear accurate under baseline conditions but may not remain so during septic shock because blood volume distribution and resistances between arterial and venous beds may change. Thus, we examined the effect of acute endotoxemia on the ability of Pmsa, estimated from steady-state cardiac output, right atrial pressure, and mean arterial pressure, to reflect our previously validated instantaneous venous return measure of mean systemic pressure (Pmsi), derived from beat-to-beat measures of right ventricular stroke volume and right atrial pressure during positive pressure ventilation. We studied 6 splenectomized pentobarbital-anesthetized close chested dogs. Right ventricular stroke volume was measured by a pulmonary arterial electromagnetic flow probe. Instantaneous venous return measure of mean systemic pressure and Pmsa were calculated during volume loading and removal (±100-mL bolus increments×5) both before (control) and 30 minutes after endotoxin infusion (endo). Cardiac output increased (2628±905 vs 3560±539 mL/min; P<.05) and mean arterial pressure decreased (107±16 vs 56±12 mm Hg; P<.01) during endo. Changes in Pmsi and Pmsa correlated during both control and endo (r2=0.7) with minimal bias by Bland-Altman analysis (mean difference±95% confidence interval, 0.47±5.04 mm Hg). We conclude that changes in Pmsa accurately tracts Pmsi under both control and endo.

Estimation of mean systemic filling pressure in postoperative cardiac surgery patients with three methods

PURPOSE

To assess the level of agreement between different bedside estimates of effective circulating blood volume-mean systemic filling pressure (Pmsf), arm equilibrium pressure (Parm) and model analog (Pmsa)-in ICU patients.

METHODS

Eleven mechanically ventilated postoperative cardiac surgery patients were studied. Sequential measures were made in the supine position, rotating the bed to a 30° head-up tilt and after fluid loading (500 ml colloid). During each condition four inspiratory hold maneuvers were done to determine Pmsf; arm stop-flow was created by inflating a cuff around the upper arm for 30 s to measure Parm, and Pmsa was estimated from a Guytonian model of the systemic circulation.

RESULTS

Mean Pmsf, Parm and Pmsa across all three states were 20.9 ± 5.6, 19.8 ± 5.7 and 14.9 ± 4.0 mmHg, respectively. Bland-Altman analysis for the difference between Parm and Pmsf showed a non-significant bias of -1.0 ± 3.08 mmHg (p = 0.062), a coefficient of variation (COV) of 15 %, and limits of agreement (LOA) of -7.3 and 5.2 mmHg. For the difference between Pmsf and Pmsa we found a bias of -6.0 ± 3.1 mmHg (p < 0.001), COV 17 % and LOA -12.4 and 0.3 mmHg. Changes in Pmsf and Parm and in Pmsf and Pmsa were directionally concordant in response to head-up tilt and volume loading.

CONCLUSIONS

Parm and Pmsf are interchangeable in mechanically ventilated postoperative cardiac surgery patients. Changes in effective circulatory volume are tracked well by changes in Parm and Pmsa.

Applying cerebral hypothermia and brain oxygen monitoring in treating severe traumatic brain injury

BACKGROUND

Severe traumatic brain injury (TBI) was to be one of the major health problems encountered in modern medicine and had an incalculable socioeconomic impact. The initial cerebral damage after acute brain injury is often exacerbated by postischemic hyperthermia and worsens the outcome. Hypothermia is one of the current therapies designed to combat this deleterious effect. The brain tissue oxygen (P(ti)o(2))-guided cerebral perfusion pressure (CPP) management was successfully reduced because of cerebral hypoxic episodes following TBI.

MATERIALS AND METHODS

Forty-five patients with severe TBI whose Glasgow Coma Scale (GCS) score ranged between 4 and 8 during September 2006 and August 2007 were enrolled in China Medical University Hospital, Taichung, Taiwan. One patient with a GCS score of 3 was excluded for poor outcome. These patients were randomized into three groups. Group A (16 patients) was intracranial pressure/cerebral perfusion pressure (ICP/CPP)-guided management only, Group B (15 patients) was ICP/CPP guided with mild hypothermia, and Group C (14 patients) was combined mild hypothermia and P(ti)o(2) guided with CPP management on patients with severe TBI. All patients were treated with ICP/CPP management (ICP <20 mm Hg, CPP >60 mm Hg). However, the group with P(ti)o(2) monitoring was required to raise the P(ti)o(2) above 20 mm Hg. Length of intensive care unit stay, ICP, P(ti)o(2), Glasgow Outcome Scale (GOS) score, mortality, and complications were analyzed.

RESULTS

The ICP values progressively increased in the first 3 days but showed smaller changes in hypothermia groups (Groups B and C) and were significantly lower than those of the normothermia group (Group A) at the same time point. We also found out that the averaged ICP were significantly related to days and the daily variations [measured as (daily observation - daily group mean)(2)] of ICP were shown to the significantly different among three treatment groups after the third posttraumatic day. The values of P(ti)o(2) in Group C tended to rise when the ICP decreased were also observed. A favorable outcome is divided by the result of GOS scores. The percentage of favorable neurologic outcome was 50% in the normothermia group, 60% in the hypothermia-only group, and 71.4% in the P(ti)o(2) group, with statistical significance. The percentage of mortality was 12.5% in the normothermia group, 6.7% in the hypothermia-only group, and 8.5% in the P(ti)o(2) group, without statistical significance in three groups. Complications included pulmonary infections, peptic ulcer, and leukocytopenia (43.8% in the normothermia group, 55.6% in the hypothermia-only group, and 50% in the P(ti)o(2) group).

CONCLUSIONS

Therapeutic mild hypothermia combined with P(ti)o(2)-guided CPP/ICP management allows reducing elevated ICP before 24 hours after injury, and daily variations of ICP were shown to be significantly different among the three treatment groups after the third posttraumatic day. It means that the hypothermia groups may reduce the ICP earlier and inhibit the elicitation of acute inflammation after cerebral contusion. Our data also provided evidence that early treatment that lowers P(ti)o(2) may improve the outcome and seems the best medical treatment method in these three groups. We concluded that therapeutic mild hypothermia combined with P(ti)o(2)-guided CPP/ICP management provides beneficial effects when treating TBI, and a multicenter randomized trial needs to be undertaken.

Brain tissue oxygen monitoring in traumatic brain injury and major trauma: outcome analysis of a brain tissue oxygen-directed therapy

OBJECT

Cerebral ischemia is the leading cause of preventable death in cases of major trauma with severe traumatic brain injury (TBI). Intracranial pressure (ICP) control and cerebral perfusion pressure (CPP) manipulation have significantly reduced the mortality but not the morbidity rate in these patients. In this study, the authors describe their 5-year experience with brain tissue oxygen (PbtO(2)) monitoring, and the effect of a brain tissue oxygen-directed critical care guide (PbtO(2)-CCG) on the 6-month clinical outcome (based on the 6-month Glasgow Outcome Scale score) in patients with TBIs.

METHODS

One hundred thirty-nine patients admitted to Creighton University Medical Center with major traumatic injuries (Injury Severity Scale [ISS] scores >or= 16) and TBI underwent prospective evaluation. All patients were treated with a PbtO(2)-CCG to maintain a brain oxygen level > 20 mm Hg, and control ICP < 20 mm Hg. The role of demographic, clinical, and imaging parameters in the identification of patients at risk for cerebral hypooxygenation and the influence of hypooxygenation on clinical outcome were recorded. Outcomes were compared with those in a historical ICP/CPP patient cohort. Subgroup analysis of severe TBI was performed and compared to data reported in the Traumatic Coma Data Bank.

RESULTS

The majority of injuries were sustained in motor vehicle crashes (63%), and diffuse brain injury was the most common abnormality (58%). Mechanism of injury, severity of TBI, pathological entity, neuroimaging results, and trauma indices were not predictive of ischemia. Factors affecting death included gunshot injury, poor trauma indices, subarachnoid hemorrhage, and coma. After standard resuscitation, 65% of patients had an initially low PbtO(2). Data are presented as means +/- SDs. Treatment with the PbtO(2)-CCG resulted in a 44% improvement in mean PbtO(2) (16.21 +/- 12.30 vs 23.65 +/- 14.40 mm Hg; p < 0.001), control of ICP (mean 12.76 +/- 6.42 mm Hg), and the maintenance of CPP (mean 76.13 +/- 15.37 mm Hg). Persistently low cerebral oxygenation was seen in 37% of patients at 2 hours, 31% at 24 hours, and 18% at 48 hours of treatment. Thus elevated ICP and a persistent low PbtO(2) after 2 hours represented increasing odds of death (OR 14.3 at 48 hours). Survivors and patients with good outcomes generally had significantly higher mean daily PbtO(2) and CPP values compared to nonsurvivors. Polytrauma, associated with higher ISS scores, presented an increased risk of vegetative outcome (OR 9.0). Compared to the ICP/CPP cohort, the mean Glasgow Outcome Scale score at 6 months in patients treated with PbtO(2)-CCG was higher (3.55 +/- 1.75 vs 2.71 +/- 1.65, p < 0.01; OR for good outcome 2.09, 95% CI 1.031-4.24) as was the reduction in mortality rate (25.9 vs 41.50%; relative risk reduction 37%), despite higher ISS scores in the PbtO(2) group (31.6 +/- 13.4 vs 27.1 +/- 8.9; p < 0.05). Subgroup analysis of severe closed TBI revealed a significant relative risk reduction in mortality rate of 37-51% compared with the Traumatic Coma Data Bank data, and an increased OR for good outcome especially in patients with diffuse brain injury without mass lesions (OR 4.9, 95% CI 2.9-8.4).

CONCLUSIONS

The prevention and aggressive treatment of cerebral hypooxygenation and control of ICP with a PbtO(2)-directed protocol reduced the mortality rate after TBI in major trauma, but more importantly, resulted in improved 6-month clinical outcomes over the standard ICP/CPP-directed therapy at the authors' institution.

Are head injury guidelines changing the outcome of head injured children? A regional investigation

BACKGROUND

Secondary pathophysiological CPP insult is related to outcome after head injury, and improved management would be expected to reduce secondary brain insult. Paediatric head injury management guidelines have been published in recent years, by SIGN (2000), RCPCH (2001), NICE (June 2003), and jointly by Critical/Intensive Care Societies (C/ICS July 2003). We investigated whether outcome of children's head injury (and total burden of secondary CPP insult) has changed (1) annually; (2) before and after the introduction of any HI guidelines, and (3) following other service changes.

METHODS

Seventy-six children (aged 1-14 years with severe HI) were admitted to the Edinburgh Regional Head Injury Service between 1989 and 2006, and dichotomised at various time points and compared in terms of: demographic factors, intracranial pressure (ICP), cerebral perfusion pressure (CPP) insults [e.g. age-banded pressure-time index (PTI)], and Glasgow Outcome Scale (GOS) score (assessed at 6 months post injury).

FINDINGS

When dichotomised around the SIGN guidelines, there were no statistically significant differences between the two group's demography or in primary brain injury, but the outcomes were different (p = 0.03), with 6 vs 4 GOS1 (died), 2 vs 4 GOS3 (severely disabled), 5 vs 16 GOS4 (moderately disabled) and 23 vs 14 GOS5 (good recovery), when comparing before and after year 2000. GOS4 was significantly different (chi-square = 7.99, p < 0.007). There was a (non-significant) trend for the later years to have longer insult durations of ICP, hypertension, CPP, hypoxia, pyrexia, tachycardia and bradycardia, greater PTI for both CPP and ICP, and more CPP insults (p = 0.003). There was, however, significantly less CPP insult (p = 0.030) after the introduction of the more management-oriented C/ICS guidelines.

CONCLUSIONS

The most recent paediatric HI guidelines appear to have reduced the burden of secondary insult, but more time is required to determine if this will be reflected in improved outcomes.

Trauma

In terms of cost and years of potential lives lost, injury arguably remains the most important public health problem facing the United States. Care of traumatically injured patients depends on early surgical intervention and avoiding delays in the diagnosis of injuries that threaten life and limb. In the critical care phase, successful outcomes after injury depend almost solely on diligence, attention to detail, and surveillance for iatrogenic infections and complications.