Continuous Monitoring of Cerebrovascular Reactivity Using Pulse Waveform of Intracranial Pressure

Background

Guidelines for the management of traumatic brain injury (TBI) call for the development of accurate methods for assessment of the relationship between cerebral perfusion pressure (CPP) and cerebral autoregulation and to determine the influence of quantitative indices of pressure autoregulation on outcome. We investigated the relationship between slow fluctuations of arterial blood pressure (ABP) and intracranial pressure (ICP) pulse amplitude (an index called PAx) using a moving correlation technique to reflect the state of cerebral vasoreactivity and compared it to the index of pressure reactivity (PRx) as a moving correlation coefficient between averaged values of ABP and ICP.

Methods

A retrospective analysis of prospective 327 TBI patients (admitted on neurocritical care unit of a university hospital in the period 2003?C2009) with continuous ABP and ICP monitoring.

Results

PAx was worse in patients who died compared to those who survived (?0.04?±?0.15 vs. ?0.16?±?0.15, ??²?=?28, p?2?=?6, p?=?0.01).

Conclusions

PAx is a new modified index of cerebrovascular reactivity which performs equally well as established PRx in long-term monitoring in severe TBI patients, but importantly is potentially more robust at lower values of ICP. In view of establishing an autoregulation-oriented CPP therapy, continuous determination of PAx is feasible but its value has to be evaluated in a prospective controlled trail.     

Early Cerebral Metabolic Crisis After TBI Influences Outcome Despite Adequate Hemodynamic Resuscitation

Background

Optimal resuscitation after traumatic brain injury (TBI) remains uncertain. We hypothesize that cerebral metabolic crisis is frequent despite adequate resuscitation of the TBI patient and that metabolic crisis negatively influences outcome.

Methods

We assessed the effectiveness of a standardized trauma resuscitation protocol in 89 patients with moderate to severe TBI, and determined the frequency of adequate resuscitation. Prospective hourly values of heart rate, blood pressure, pulse oximetry, intracranial pressure (ICP), respiratory rate, jugular venous oximetry, and brain extracellular values of glucose, lactate, pyruvate, glycerol, and glutamate were obtained. The incidence during the initial 72?h after injury of low brain glucose <0.8?mmol/L, elevated lactate/pyruvate ratio (LPR) >25, and metabolic crisis, defined as the simultaneous occurrence of both low glucose and high LPR, were determined for the group.

Results

5 patients were inadequately resuscitated and eight patients had intractable ICP. In patients with successful resuscitation and controlled ICP (n?=?76), within 72?h of trauma, 76?% had low glucose, 93?% had elevated LPR, and 74?% were in metabolic crisis. The duration of metabolic crisis was longer in those patients with unfavorable (GOSe????6) versus favorable (GOSe????7) outcome at 6?months (P?=?0.011). In four multivariate models the burden of metabolic crisis was a powerful independent predictor of poor outcome.

Conclusions

Metabolic crisis occurs frequently after TBI despite adequate resuscitation and controlled ICP, and is a strong independent predictor of poor outcome at 6?months.     

Predictors of poor outcome of decompressive craniectomy in pediatric patients with severe traumatic brain injury: a retrospective single center study from Pakistan

Objective

This study aimed to determine the risk factors associated with poor outcome of decompressive craniectomy (DC) for severe traumatic brain injury (TBI) in pediatric patients.

Methods

This retrospective study is conducted on pediatric population (age 1–15 years) presenting with TBI who underwent DC at our institute between January 2000 and 2010. Based on Glasgow outcome score (GOS) at a minimum follow-up of 5 months, patients were divided into two groups, namely poor outcome (GOS 1, 2, and 3) and good outcome (GOS 4 and 5). Records were reviewed and analyzed for preoperative and intraoperative predictors.

Results

We found 25 patients who were eligible as per selection criteria. Mean age at presentation was 6?±?4 years and there was male preponderance (84 %). Fall (60 %) was the most common mechanism of injury followed by gunshots and road traffic accident. On univariate analysis, presenting GCS ≤5 (p value?=?0.009), delay in presentation of more than 150 min (p value?=?0.010), DC performed after more than 4 h of arrival in hospital (p value?=?0.042), and intraoperative blood loss exceeding 300 ml (p value?=?0.001) were significant predictors of poor outcome.

Conclusion

Our study suggests that DC in children is not only a life-saving procedure, but also leads to a good functional outcome after severe injury. However, patient selection still remains an important aspect, and the above-mentioned factors should be considered while deciding for DC to improve survival. Further prospective studies on larger sample size are warranted to validate our results.     

Intraoperative secondary insults during extracranial surgery in children with traumatic brain injury

Purpose

Data on intraoperative secondary insults in pediatric traumatic brain injury (TBI) are limited.

Methods

We examined intraoperative secondary insults during extracranial surgery in children with moderate-severe TBI and polytrauma and their association with postoperative head computed tomography (CT) scans, intracranial pressure (ICP), and therapeutic intensity level (TIL) scores 24 h after surgery. After IRB approval, we reviewed the records of children <18 years with a Glasgow Coma Scale score <13 who underwent extracranial surgery within 72 h of TBI. Definitions of secondary insults were as follows: systemic hypotension (SBP <70?+?2?×?age or 90 mmHg), cerebral hypotension (cerebral perfusion pressure <40 mmHg), intracranial hypertension (ICP >20 mmHg), hypoxia (oxygen saturation <90 %), hypercarbia (end-tidal CO₂ >45 mmHg), hypocarbia (end-tidal CO₂ <30 mmHg without hypotension and in the absence of intracranial hypertension), hyperglycemia (blood glucose >200 mg/dL), hyperthermia (temperature >38 °C), and hypothermia (temperature <35 °C).

Results

Data from 50 surgeries in 42 patients (median age 15.5 years, 25 males) revealed systemic hypotension during 78 %, hypocarbia during 46 %, and hypercarbia during 25 % surgeries. Intracranial hypertension occurred in 64 % and cerebral hypotension in 18 % surgeries with ICP monitoring (11/50). Hyperglycemia occurred during 17 % of the 29 surgeries with glucose monitoring. Cerebral hypotension and hypoxia were associated with postoperative intracranial hypertension (p?=?0.02 and 0.03, respectively). We did not observe an association between intraoperative secondary insults and postoperative worsening of head CT scan or TIL score.

Conclusions

Intraoperative secondary insults were common during extracranial surgery in pediatric TBI. Intraoperative cerebral hypotension and hypoxia were associated with postoperative intracranial hypertension. Strategies to prevent secondary insults during extracranial surgery in TBI are needed.     

Effect of Percutaneous Tracheostomy on Intracerebral Pressure and Perfusion Pressure in Patients with Acute Cerebral Dysfunction (TIP Trial): An Observational Study

Background

Bedside percutaneous tracheostomy (PT) is very commonly used for patients who require prolonged mechanical ventilation. The effect of tracheostomy on intracranial pressure (ICP) is currently a subject of controversy. The aim of our study is to clarify the relation between PT and its effect on ICP and cerebral perfusion pressure.

Methods

38 patients on our intensive care unit were included prospectively in an observational study. We examined mean values of HF, SpO₂, ICP, CPP, and MAP for changes over five different phases of the procedure using paired Mann?CWhitney U tests. A p value of <0.05 was considered significant. p values were Bonferroni corrected for multiple testing.

Results

PT was performed on 38 patients (f?=?19, m?=?19; mean?=?56?years). Median ICP before intervention was 9?mmHg. During positioning of the patient, ICP had risen to 14, during bronchoscopy to 16, and during tracheostomy to 18?mmHg, all being significantly higher than baseline level. Monitoring of MAP showed a significant increase to 101?mmHg only during tracheostomy. SpO₂ and HF did not show any significant changes. Mean duration of positioning, bronchoscopy and tracheostomy was 19, 10, and 17?min. 8 patients received osmotherapy due to a rise of ICP of more than 30?mmHg.

Conclusion

PT only leads to a significant rise of ICP during the procedure. Nevertheless, therapy of ICP is necessary in some patients. From our point of view, therefore, tracheostomy should only be performed under continuous monitoring of ICP and CPP in patients with severe cerebral dysfunctions and critically elevated ICP.     

Intermittent Versus Continuous Cerebrospinal Fluid Drainage Management in Adult Severe Traumatic Brain Injury: Assessment of Intracranial Pressure Burden

Introduction

There is clinical equipoise regarding whether neurointensive care unit management of external ventricular drains (EVD) in severe traumatic brain injury (TBI) should involve an open EVD, with continuous drainage of cerebrospinal fluid (CSF), versus a closed EVD, with intermittent opening as necessary to drain CSF. In a matched cohort design, we assessed the relative impact of continuous versus intermittent CSF drainage on intracranial pressure in the management of adult severe TBI.

Methods

Sixty-two severe TBI patients were assessed. Thirty-one patients managed by open EVD drainage were matched by age, sex, and injury severity (initial Glasgow Coma Scale (GCS) score) to 31 patients treated with a closed EVD drainage. Patients in the open EVD group also had a parenchymal intracranial pressure (ICP) monitor placed through an adjacent burr hole, allowing real-time recording of ICP. Hourly ICP and other pertinent data, such as length of stay in intensive care unit (LOS-ICU), Injury Severity Score, and survival status, were extracted from our prospective database.

Results

With age, injury severity (initial GCS score), and neurosurgical intervention adjusted for, there was a statistically significant difference of 5.66 mmHg in mean ICP (p < 0.0001) between the open and the closed EVD groups, with the closed EVD group exhibiting greater mean ICP. ICP burden (ICP ≥ 20 mmHg) was shown to be significantly higher in the intermittent EVD group (p = 0.0002) in comparison with the continuous EVD group.

Conclusion

Continuous CSF drainage via an open EVD seemed to be associated with more effective ICP control in the management of adult severe TBI.     

Monitoring cerebral autoregulation after head injury. Which component of transcranial Doppler flow velocity is optimal?

Background

Cerebral autoregulation assessed using transcranial Doppler (TCD) mean flow velocity (FV) in response to various physiological challenges is predictive of outcome after traumatic brain injury (TBI). Systolic and diastolic FV have been explored in other diseases. This study aims to evaluate the systolic, mean and diastolic FV for monitoring autoregulation and predicting outcome after TBI.

Methods

300 head-injured patients with blood pressure (ABP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), and FV recordings were studied. Autoregulation was calculated as a correlation of slow changes in diastolic, mean and systolic components of FV with CPP (Dx, Mx, Sx, respectively) and ABP (Dxa, Mxa, Sxa, respectively) from 30 consecutive 10?s averaged values. The relationship with age, severity of injury, and dichotomized 6?months outcome was examined.

Results

Association with outcome was significant for Mx and Sx. For favorable/unfavorable and death/survival outcomes Sx showed the strongest association (F?=?20.11; P?=?0.00001 and F?=?13.10; P?=?0.0003, respectively). Similarly, indices derived from ABP demonstrated the highest discriminatory value when systolic FV was used (F?=?12.49; P?=?0.0005 and F?=?5.32; P?=?0.02, respectively). Indices derived from diastolic FV demonstrated significant differences (when calculated using CPP) only when comparing between fatal and non-fatal outcome.

Conclusions

Systolic flow indices (Sx and Sxa) demonstrated a stronger association with outcome than the mean flow indices (Mx and Mxa), irrespective of whether CPP or ABP was used for calculation.     

Does Affective Valence During and Immediately Following a 10-Min Walk Predict Concurrent and Future Physical Activity?

Background

Affect may be important for understanding physical activity behavior.

Purpose

To examine whether affective valence (i.e., good/bad feelings) during and immediately following a brief walk predicts concurrent and future physical activity.

Methods

At months?6 and 12 of a 12-month physical activity promotion trial, healthy low-active adults (N?=?146) reported affective valence during and immediately following a 10-min treadmill walk. Dependent variables were self-reported minutes/week of lifestyle physical activity at months?6 and 12.

Results

Affect reported during the treadmill walk was cross-sectionally (month?6: ???=?28.6, p?=?0.008; month 12: ???=?26.6, p?=?0.021) and longitudinally (???=?14.8, p?=?0.030) associated with minutes/week of physical activity. Affect reported during a 2-min cool down was cross-sectionally (month 6: ???=?21.1, p?=?0.034; month 12: ???=?30.3, p?<?0.001), but not longitudinally associated with minutes/week of physical activity. Affect reported during a postcool-down seated rest was not associated with physical activity.

Conclusions

During-behavior affect is predictive of concurrent and future physical activity behavior.     

Increased CSF Concentrations of Myelin Basic Protein After TBI in Infants and Children: Absence of Significant Effect of Therapeutic Hypothermia

Background

The objectives of this study were to determine effects of severe traumatic brain injury (TBI) on cerebrospinal fluid (CSF) concentrations of myelin basic protein (MBP) and to assess relationships between clinical variables and CSF MBP concentrations.

Methods

We measured serial CSF MBP concentrations in children enrolled in a randomized controlled trial evaluating therapeutic hypothermia (TH) after severe pediatric TBI. Control CSF was obtained from children evaluated, but found not to be having CNS infection. Generalized estimating equation models and Wilcoxon Rank-Sum test were used for comparisons of MBP concentrations.

Results

There were 27 TBI cases and 57 controls. Overall mean (±SEM) TBI case MBP concentrations for 5?days after injury were markedly greater than controls (50.49?±?6.97 vs. 0.11?±?0.01?ng/ml, p?<?0.01). Mean MBP concentrations were lower in TBI patients <1?year versus >1?year (9.18?±?1.67 vs. 60.22?±?8.26?ng/ml, p?=?0.03), as well as in cases with abusive head trauma (AHT) versus non-abusive TBI (14.46?±?3.15 vs. 61.17?±?8.65?ng/ml, p?=?0.03). TH did not affect MBP concentrations.

Conclusions

Mean CSF MBP increases markedly after severe pediatric TBI, but is not affected by TH. Infancy and AHT are associated with low MBP concentrations, suggesting that age-dependent myelination influences MBP concentrations after injury. Given the magnitude of MBP increases, axonal injury likely represents an important therapeutic target in pediatric TBI.     

Decompressive Craniectomy in Patients with Traumatic Brain Injury: Are the Usual Indications Congruent with Those Evaluated in Clinical Trials?

Background

In patients with traumatic brain injury (TBI), multicenter randomized controlled trials have assessed decompressive craniectomy (DC) exclusively as treatment for refractory elevation of intracranial pressure (ICP). DC reliably lowers ICP but does not necessarily improve outcomes. However, some patients undergo DC as treatment for impending or established transtentorial herniation, irrespective of ICP.

Methods

We performed a population-based cohort study assessing consecutive patients with moderate–severe TBI. Indications for DC were compared with enrollment criteria for the DECRA and RESCUE-ICP trials.

Results

Of 644 consecutive patients, 51 (8 %) were treated with DC. All patients undergoing DC had compressed basal cisterns, 82 % had at least temporary preoperative loss of ≥1 pupillary light reflex (PLR), and 80 % had >5 mm of midline shift. Most DC procedures (67 %) were “primary,” having been performed concomitantly with evacuation of a space-occupying lesion. ICP measurements influenced the decision to perform DC in 18 % of patients. Only 10 and 16 % of patients, respectively, would have been eligible for the DECRA and RESCUE-ICP trials. DC improved basal cistern compression in 76 %, and midline shift in 94 % of patients. Among patients with ≥1 absent PLR at admission, DC was associated with lower mortality (46 vs. 68 %, p = 0.03), especially when the admission Marshall CT score was 3–4 (p = 0.0005). No patients treated with DC progressed to brain death. Variables predictive of poor outcome following DC included loss of PLR(s), poor motor score, midline shift ≥11 mm, and development of perioperative cerebral infarcts.

Conclusions

DC is most often performed for clinical and radiographic evidence of herniation, rather than for refractory ICP elevation. Results of previously completed randomized trials do not directly apply to a large proportion of patients undergoing DC in practice.

     

Admission oxygenation and ventilation parameters associated with discharge survival in severe pediatric traumatic brain injury

Purpose

Current Brain Trauma Foundation guidelines recommend avoiding hypoxemia after severe pediatric traumatic brain injury (TBI). Yet, recent studies on optimum admission oxygenation and ventilation parameters associated with discharge survival in pediatric TBI are lacking.

Materials and methods

After IRB approval, a retrospective study involving pediatric patients ages ≤14 years with severe TBI (head Abbreviated Injury Scale (AIS) score of ≥3, Glasgow Coma Scale score of ≤8 on admission) admitted to Harborview Medical Center (level 1 pediatric trauma center), Seattle, WA, during 2003 to 2007 was performed. Admission demographics, clinical data, and laboratory characteristics were abstracted. Hypoxemia was defined as PaO₂?<?60 mmHg, hypocarbia was defined as PaCO₂?≤?35 mmHg, and hypercarbia was defined as PaCO₂?≥?46 mmHg.

Results

One hundred ninety-four patients met inclusion criteria of which 162 (83.5 %) patients survived. Admission hypoxemia occurred in nine (5.6 %) patients who survived and eight (25 %) patients who died (p?<?0.001). Children with admission PaCO₂ between 36 and 45 mmHg had greater discharge survival compared with those with both admission hypocarbia (PaCO₂?≤?35 mmHg) and hypercarbia (PaCO₂?≥?46 mmHg). Admission PaO₂ 301–500 mmHg (adjusted odds ratio (AOR), 8.02 (95 % confidence interval (CI), 1.73–37.10); p?=?0.008) and admission PaCO₂?=?36–45 mmHg (AOR, 5.47 (95 % CI, 1.30–23.07); p?=?0.02) were independently associated with discharge survival.

Conclusions

Discharge survival after severe pediatric TBI was associated with admission PaO₂ 301–500 mmHg and PaCO₂?=?36–45 mmHg. Admission hypocarbia and hypercarbia were each associated with increased discharge mortality.     

Goal Directed Brain Tissue Oxygen Monitoring Versus Conventional Management in Traumatic Brain Injury: An Analysis of In Hospital Recovery

Background

Brain tissue oxygen monitoring (pBtO2) has been advocated in the treatment of patients with severe traumatic brain injuries (TBI); however, controversy exists regarding the improvements that pBtO2 monitoring provides. The objective of our study was to evaluate our experience and effect on mortality with goal directed pBtO2 monitoring for severe TBI compared to traditional ICP/CPP monitoring.

Methods

All patients admitted with severe TBI (GCS < 8) to our Level 1 trauma center from June 2007 through June 2009 were retrospectively analyzed. All patients had ICP monitoring and pBtO2 monitors were placed based on the current practices of the attending neurosurgeon producing two temporally matched cohorts of patients with and without pBtO2 monitors. Exclusion criteria were age <18 years and survival <24 h. Goal-directed therapy was utilized in all patients to maintain ICP <20 mmHg and CPP >60 mmHg. Patients with pBtO2 monitors were managed to maintain a level >20 mmHg.

Results

74 patients were treated for severe TBI over the 2-year study period with 37 patients in each group. Both groups were similar in age, sex, and admission Glascow Coma Score(GCS).The pBtO2-monitored group did, however, have significantly lower injury severity score [26 (25–30) vs. 30 (26–36), p = 0.03] and AIS Chest [0 (0–0) vs. 2 (0–3), p = 0.02]. There was no survival difference found (64.9 vs. 54.1 %, p = 0.34). No difference with respect to discharge GCS or discharge Functional Independence Measure score was identified.

Conclusions

Compared with ICP/CPP-directed therapy alone, the addition of pBtO2 monitoring did not provide a survival or functional status improvement at discharge. The true clinical benefit of pBtO2 monitoring will require further study.     

Preoperative and postoperative neurological, neuropsychological and behavioral impairment in children with posterior cranial fossa astrocytomas and medulloblastomas: the role of the tumor and the impact of the surgical treatment

Introduction

The aim of the present study was to prospectively investigate if a correlation might exist between preoperative and postoperative neurological conditions, neuroradiological/intraoperative findings and results of a complete neuropsychological evaluation in children with posterior fossa medulloblastomas and astrocytomas.

Materials and methods

Of the 65 children admitted at the Pediatric Neurosurgery of the UCSC of Rome between January 2005 and October 2009, 41 were selected; the only two exclusion criteria were represented by age under 24 months and severe neurological conditions, seen that in both cases it would not have been a possible reliable evaluation. All children underwent a preoperative and immediate postoperative complete MR study. Hydrocephalus was graded on the Evans score; brainstem infiltration was defined on intraoperative findings. Neuropsychological assessment consisted of a battery of tests tailored on the patient’s age, cognitive level, and level of cooperation. Post operative neuropsychological evaluation was performed at a mean time of 2.5 min (2 mos, max 4.5 mos) from the operation, before any eventually needed adjuvant treatment (i.e., chemotherapy, radiotherapy).

Results

Concerning neurological status, we found a statistically significant relation between the presence of oculomotor impairment and both verbal fluency deficits (p?=?0.044) and imagery disorders (p?=?0.03); also, the presence of ataxia/dysmetria was significantly correlated to attention dysfunction (p?=?0.01) and, more tightly, to planning dysfunction (p?=?0.006). For neuroradiological/intraoperative features, Intelligence Quotient (IQ) impairment was significantly correlated to the intraoperative evidence of tumor infiltration of the brainstem (p?=?0.003), a severe hydrocephalus at diagnosis (p?=?0.001) and the histological diagnosis of medulloblastoma (MB) (p?=?0.002). For selective skills, a significant correlation was found between linguistic processing deficits and the evidence of dentate nuclei infiltration (blindly defined on MR); procedural memory defects and imagery disorders related to the severity of the hydrocephalus (p?=?0.02), infiltration of the brain stem (p?=?0.01) and a histological diagnosis of MB (p?=?0.01). After surgery no patient showed a worsening of his/her cognitive profile; the relationships between clinical, intraoperative, and radiological findings were substantially confirmed.

Discussion

Our results support the hypothesis that when present, neuropsychological impairment is already present at diagnosis and that the most statistically significant factors, which might be related with cognitive deficits in the preoperative as well as in the postoperative period, are tumor infiltration of the brainstem, the severity of hydrocephalus, and a histological diagnosis of MB.     

A Continuous Correlation Between Intracranial Pressure and Cerebral Blood Flow Velocity Reflects Cerebral Autoregulation Impairment During Intracranial Pressure Plateau Waves

Background

In the healthy brain, small oscillations in intracranial pressure (ICP) occur synchronously with those in cerebral blood volume (CBV), cerebrovascular resistance, and consequently cerebral blood flow velocity (CBFV). Previous work has shown that the usual synchrony between ICP and CBFV is lost during intracranial hypertension. Moreover, a continuously computed measure of the ICP/CBFV association (Fix index) was a more sensitive predictor of outcome after traumatic brain injury (TBI) than a measure of autoregulation (Mx index). In the current study we computed Fix during ICP plateau waves, to observe its behavior during a defined period of cerebrovascular vasodilatation.

Methods

Twenty-nine recordings of arterial blood pressure (ABP), ICP, and CBFV taken during ICP plateau waves were obtained from the Addenbrooke’s hospital TBI database. Raw data was filtered prior to computing Mx and Fix according to previously published methods. Analyzed data was segmented into three phases (pre, peak, and post), and a median value of each parameter was stored for analysis.

Results

ICP increased from a median of 22–44 mmHg before falling to 19 mmHg. Both Mx and Fix responded to the increase in ICP, with Mx trending toward +1, while Fix trended toward ?1. Mx and Fix correlated significantly (Spearman’s R = ?0.89, p < 0.000001), however, Fix spanned a greater range than Mx. A plot of Mx and Fix against CPP showed a plateau (Mx) or trough (Fix) consistent with a zone of “optimal CPP”.

Conclusions

The Fix index can identify complete loss of cerebral autoregulation as the point at which the normally positive CBF/CBV correlation is reversed. Both CBF and CBV can be monitored noninvasively using near-infrared spectroscopy (NIRS), suggesting that a noninvasive method of monitoring autoregulation using only NIRS may be possible.     

Hypertonic Saline Reduces Intracranial Hypertension in the Presence of High Serum and Cerebrospinal Fluid Osmolalities

Background

Osmotherapy has been the cornerstone in the management of patients with elevated intracranial pressure (ICP) following traumatic brain injury (TBI). Several studies have demonstrated that hypertonic saline (HTS) is a safe and effective osmotherapy agent. This study evaluated the effectiveness of HTS in reducing intracranial hypertension in the presence of a wide range of serum and cerebrospinal fluid (CSF) osmolalities.

Methods

Forty-two doses of 23.4% saline boluses for treatment of refractory intracranial hypertension were reviewed retrospectively. Thirty milliliters of 23.4% NaCl was infused over 15?min for intracranial hypertension, defined as ICP?>20?mmHg. The CSF and serum osmolalities from frozen stored samples were measured with an osmometer. The values of serum sodium, hourly ICP, blood urea nitrogen (BUN), and creatinine were obtained directly from the medical records.

Results

The serum and CSF osmolalities correlated very closely to serum sodium (r?>?0.9, P?P?320 as it was at???320.

Conclusion

This study demonstrates that 23.4% HTS bolus is effective for the reduction of elevated ICP in patients with severe TBI even in the presence of high serum and CSF osmolalities.     

Intracranial Pressure During Pressure Control and Pressure-Regulated Volume Control Ventilation in Patients with Traumatic Brain Injury: A Randomized Crossover trial

Introduction

Mechanical ventilation with control of partial arterial CO₂ pressures (PaCO₂) is used to treat or stabilize intracranial pressure (ICP) in patients with traumatic brain injury (TBI). Pressure-regulated volume control (PRVC) is a ventilator mode where inspiratory pressures are automatically adjusted to deliver the patient a pre-set stable tidal volume (TV). This may result in a more stable PaCO₂ and thus a more stable ICP compared with conventional pressure control (PC) ventilation. The aim of this study was to compare PC and PRVC ventilation in TBI patients with respect to ICP and PaCO₂.

Methods

This is a randomized crossover trial including eleven patients with a moderate or severe TBI who were mechanically ventilated and had ICP monitoring. Each patient was administered alternating 2-h periods of PC and PRVC ventilation. The outcome variables were ICP and PaCO₂.

Results

Fifty-two (26 PC, 26 PRVC) study periods were included. Mean ICP was 10.8 mmHg with PC and 10.3 mmHg with PRVC ventilation (p = 0.38). Mean PaCO₂ was 36.5 mmHg (4.87 kPa) with PC and 36.1 mmHg (4.81 kPa) with PRVC (p = 0.38). There were less fluctuations in ICP (p = 0.02) and PaCO₂ (p = 0.05) with PRVC ventilation.

Conclusions

Mean ICP and PaCO₂ were similar for PC and PRVC ventilation in TBI patients, but PRVC ventilation resulted in less fluctuation in both ICP and PaCO₂. We cannot exclude that the two ventilatory modes would have impact on ICP in patients with higher ICP values; however, the similar PaCO₂ observations argue against this.

     

The value of transcranial Doppler imaging in children with tuberculous meningitis

Purpose

Transcranial Doppler imaging (TCDI) is potentially a valuable investigational tool in children with tuberculous meningitis (TBM), a condition often complicated by pathology relevant to Doppler imaging such as raised intracranial pressure (ICP) and cerebral vasculopathies.

Methods

Serial TCDI was performed on 20 TBM children with the aim of investigating cerebrovascular haemodynamics and the relationship between pulsatility index (PI) and ICP.

Results

We observed a poor correlation between ICP and PI in children with communicating hydrocephalus (p?=?0.72). No decline in PI was noted following 7 days of medical therapy for communicating hydrocephalus (p?=?0.78) despite a concomitant decline in ICP. Conversely, a decline in PI was noted in all four children with non-communicating hydrocephalus who underwent cerebrospinal fluid diversion. High blood flow velocities (BFV) in all the basal cerebral arteries were observed in 14 children (70 %). The high BFV persisted for 7 days suggesting stenosis due to vasculitis rather than functional vasospasm. Complete middle cerebral artery (MCA) occlusion, subnormal mean MCA velocities (<40 cm/s) and PIs (<0.4) correlated with radiologically proven large cerebral infarcts.

Conclusions

TCDI-derived PI is not a reliable indicator of raised ICP in children with tuberculous hydrocephalus. This may be attributed to individual variation of tuberculous vascular disease, possibly compromising cerebral vascular compliance and resistance. Basal artery stenosis secondary to vasculitis is observed during the acute stage of TBM in the majority of children.     

Association Between Optic Nerve Sheath Diameter and Mortality in Patients with Severe Traumatic Brain Injury

Purpose

Increased intracranial pressure (ICP) is associated with worse outcomes following traumatic brain injury (TBI). Studies have confirmed that ICP is correlated with optic nerve sheath diameter (ONSD) on ultrasound. The aim of our study was to assess the independent relationship between ONSD measured using CT and mortality in a population of patients admitted with severe TBI.

Methods

We conducted a retrospective cohort study of patients with a TBI requiring ICP monitoring admitted to the ICU between April 2006 and May 2012 to two neurotrauma centers. ONSD was independently measured by two physicians blinded to patient outcomes. Multivariable logistic regression modeling was used to assess an association between ONSD and hospital mortality.

Results

A total of 220 patients were included in the analysis. Overall, the cohort had a mean age of 35 (SD 17) years and 171 of 220 (79 %) were male. The median admission GCS was 6 (IQR 3–8). Intra-class correlation coefficient between raters for ONSD measurements was 0.92 (95 % CI 0.90–0.94, P < 0.0001). On multivariable analysis, each 1 mm increase in ONSD was associated with a twofold increase in hospital mortality (OR 2.0, 95 % CI 1.2–3.2, P = 0.007). Using linear regression, ONSD was independently associated with increased ICP in the first 48 h after admission (β = 4.4, 95 % CI 2.5–6.3, P < 0.0001).

Conclusions

In patients with TBI, ONSD measured on CT scanning was independently associated with ICP and mortality.     

Sexual Orientation and Gender Differences in Markers of Inflammation and Immune Functioning

Background

Sexual minorities have documented elevated risk factors that can lead to inflammation and poor immune functioning.

Purpose

This study aims to investigate disparities in C-reactive protein (CRP) and Epstein–Barr virus (EBV) by gender and sexual orientation.

Methods

We used the National Longitudinal Study of Adolescent Health to examine disparities in CRP (N?=?11,462) and EBV (N?=?11,812).

Results

Among heterosexuals, women had higher levels of CRP and EBV than men. However, sexual minority men had higher levels of CRP and EBV than heterosexual men and sexual minority women. Lesbians had lower levels of CRP than heterosexual women.

Conclusions

Gender differences in CRP and EBV found between men and women who identify as 100 % heterosexual were reversed among sexual minorities and not explained by known risk factors (e.g., victimization, alcohol and tobacco use, and body mass index). More nuanced approaches to addressing gender differences in sexual orientation health disparities that include measures of gender nonconformity and minority stress are needed.