Escalation therapy in severe traumatic brain injury: how long is intracranial pressure monitoring necessary?

Correlation between optic nerve sheath diameter measured by bedside ultrasound and intracranial pressure in neurologically ill patients in a Chinese population

BACKGROUND

We assessed the correlation between optic nerve sheath diameter (ONSD) values measured by bedside ultrasound and intracranial pressure (ICP) changes among patients under neurocritical care and evaluated the diagnostic performance of ONSD for increased ICP.

METHODS

Sixty-seven neurologically critical patients who were hospitalised in the intensive care unit (ICU) of Jining No.1 People's Hospital between September 2023 and March 2024 and underwent lumbar puncture were included. The ONSD was measured and recorded using bedside ultrasound before the lumbar puncture. Patients were divided into normal and increased ICP groups on the basis of the initial lumbar puncture pressure on admission, and both groups were compared. Spearman's correlation analysis was used for evaluating the correlation between ONSD values and ICP. Receiver operating characteristic (ROC) curves were employed for evaluating the diagnostic performance of ONSD for increased ICP.

RESULT

At admission, the Glasgow Coma Scale scores of patients in the increased ICP group were significantly lower than those of patients in the normal ICP group (P < 0.05). The ONSD level of patients in the increased ICP group was significantly higher than that of patients in the normal ICP group (P < 0.05). Spearman's correlation analysis revealed that ONSD positively correlated with ICP among patients with severe neurological diseases (r = 0.777, P < 0.001). The area under the ROC curve when using ONSD for diagnosing lumbar puncture opening pressure ≥ 200 mmH2O was 0.896 (95% confidence interval, 0.817-0.974). When using ONSD ≥ 4.74 mm as the threshold for diagnosing lumbar puncture opening pressure ≥ 200 mmH2O, the sensitivity and specificity were 0.909 and 0.765, respectively.

CONCLUSION

In patients with critical neurological illness, ONSD measured using bedside ultrasound positively correlated with ICP. Increased ICP can be diagnosed for ONSD ≥ 4.74 mm. The ONSD value measured by bedside ultrasound can be used for evaluating ICP among patients with critical neurological illness.

In Situ Polymer-Solution-Processed Graphene-PDMS Nanocomposites for Application in Intracranial Pressure Sensors

Polydimethylsiloxane (PDMS) has emerged as a promising candidate for the dielectric layer in implantable sensors due to its exceptional biocompatibility, stability, and flexibility. This study introduces an innovative approach to produce graphene-reinforced PDMS (Gr-PDMS), where graphite powders are exfoliated into mono- and few-layer graphene sheets within the polymer solution, concurrently forming cross-linkages with PDMS. This method yields a uniformly distributed graphene within the polymer matrix with improved interfaces between graphene and PDMS, significantly reducing the percolation threshold of graphene dispersed in PDMS from 10% to 5%. As-synthesized Gr-PDMS exhibits improved mechanical and electrical properties, tested for potential use in capacitive pressure sensors. The results demonstrate an impressive pressure sensitivity up to 0.0273 kpa-1, 45 times higher than that of pristine PDMS and 2.5 times higher than the reported literature value. The Gr-PDMS showcases excellent pressure sensing ability and stability, fulfilling the requirements for implantable intracranial pressure (ICP) sensors.

Critical ICP thresholds in relation to outcome: Is 22 mmHg really the answer?

PURPOSE

Intensive care for patients with traumatic brain injury (TBI) aims, among other tasks, at avoiding high intracranial pressure (ICP), which is perceived to worsen motor and cognitive deficits and increase mortality. International recommendations for threshold values for ICP were increased from 20 to 22 mmHg in 2016 following the findings in a study by Sorrentino et al., which were based on an observational study of patients with TBI of averaged ICP values. We aimed to reproduce their approach and validate the findings in a separate cohort.

METHODS

Three hundred thirty-one patients with TBI were included and categorised according to survival/death and favourable/unfavourable outcome at 6 months (based on Glasgow Outcome Score-Extended of 6-8 and 1-5, respectively). Repeated chi-square tests of survival and death (or favourable and unfavourable outcome) vs. high and low ICP were conducted with discrimination between high and low ICP sets at increasing values (integers) between 10 and 35 mmHg, using the average ICP for the entire monitoring period. The ICP limit returning the highest chi-square score was assumed to be the threshold with best discriminative ability. This approach was repeated after stratification by sex, age, and initial Glasgow Coma Score (GCS).

RESULTS

An ICP limit of 18 mmHg was found for both mortality and unfavourable outcome for the entire cohort. The female and the low GCS subgroups both had threshold values of 18 mmHg; for all other subgroups, the threshold varied between 16 and 30 mmHg. According to a multiple logistic regression analysis, age, initial GCS, and average ICP are independently associated with mortality and outcome.

CONCLUSIONS

Using identical methods and closely comparable cohorts, the critical thresholds for ICP found in the study by Sorrentino et al. could not be reproduced.

Monitoring of Brain Tissue Oxygen Tension in Cardiac Arrest: a Translational Systematic Review from Experimental to Clinical Evidence

BACKGROUND

Cardiac arrest (CA) is a sudden event that is often characterized by hypoxic-ischemic brain injury (HIBI), leading to significant mortality and long-term disability. Brain tissue oxygenation (PbtO2) is an invasive tool for monitoring brain oxygen tension, but it is not routinely used in patients with CA because of the invasiveness and the absence of high-quality data on its effect on outcome. We conducted a systematic review of experimental and clinical evidence to understand the role of PbtO2 in monitoring brain oxygenation in HIBI after CA and the effect of targeted PbtO2 therapy on outcomes.

METHODS

The search was conducted using four search engines (PubMed, Scopus, Embase, and Cochrane), using the Boolean operator to combine mesh terms such as PbtO2, CA, and HIBI.

RESULTS

Among 1,077 records, 22 studies were included (16 experimental studies and six clinical studies). In experimental studies, PbtO2 was mainly adopted to assess the impact of gas exchanges, drugs, or systemic maneuvers on brain oxygenation. In human studies, PbtO2 was rarely used to monitor the brain oxygen tension in patients with CA and HIBI. PbtO2 values had no clear association with patients' outcomes, but in the experimental studies, brain tissue hypoxia was associated with increased inflammation and neuronal damage.

CONCLUSIONS

Further studies are needed to validate the effect and the threshold of PbtO2 associated with outcome in patients with CA, as well as to understand the physiological mechanisms influencing PbtO2 induced by gas exchanges, drug administration, and changes in body positioning after CA.

Trauma Anesthesiology Perioperative Management Update

Anesthesia for patients with life-threatening injuries is an essential part of post-accident care. Unfortunately, there is variability in trauma anesthesia care and numerous nonstandardized methods of working with patients remain. Uncertainty exists as to when and how best to intubate trauma patients, the use of vasopressors, and the appropriate management of severe traumatic brain injury. Some physicians recommend prehospital rapid sequence intubation, whereas others use bag-mask ventilation at lower pressures with no cricoid pressure and early transport to a trauma center. Overall, the absence of uniformity in trauma anesthesia care underlines the need for continued study and dialogue to define best practices and optimize patient outcomes.

Impact of Intracranial Hypertension on Outcome of Severe Traumatic Brain Injury Pediatric Patients: A 15-Year Single Center Experience

Background: Intracranial hypertension (IC-HTN) is significantly associated with higher risk for an unfavorable outcome in pediatric trauma. Intracranial pressure (ICP) monitoring is widely becoming a standard of neurocritical care for children. Methods: The present study was designed to evaluate influences of IC-HTN on clinical outcomes of pediatric TBI patients. Demographic, injury severity, radiologic characteristics were used as possible predictors of IC-HTN or of functional outcome. Results: A total of 118 pediatric intensive care unit (PICU) patients with severe TBI (sTBI) were included. Among sTBI cases, patients with GCS < 5 had significantly higher risk for IC-HTN and for mortality. Moreover, there was a statistically significant positive correlation between IC-HTN and severity scoring systems. Kaplan−Meier analysis determined a significant difference for good recovery among patients who had no ICP elevations, compared to those who had at least one episode of IC-HTN (log-rank chi-square = 11.16, p = 0.001). A multivariable predictive logistic regression analysis distinguished the ICP-monitored patients at risk for developing IC-HTN. The model finally revealed that higher ISS and Helsinki CT score increased the odds for developing IC-HTN (p < 0.05). Conclusion: The present study highlights the importance of ICP-guided clinical practices, which may lead to increasing percentages of good recovery for children.

Effect of Mild Hypothermia after Craniotomy on the Function of Related Organs in Patients with Traumatic Brain Injury

OBJECTIVE

To investigate the effect of mild hypothermia after craniotomy on the function of related organs in patients with traumatic brain injury.

METHOD

A total of 240 patients with craniocerebral injury from January 2017 to December 2020 were retrospectively analyzed. Patients were randomly divided into a control group and an experimental group, with 120 cases in each group. The control group was treated with craniotomy decompression, and the experimental group was treated with early mild hypothermia based on craniotomy decompression. Patients' venous blood was collected before operation (T 0), at the end of operation (T 1), 24 h after operation (T 2), and 2 weeks after operation (T 3) to detect the serum levels of the beta-subunit of S100 protein (S100-β); soluble growth stimulation expressed gene 2 (sST2), neutrophil gelatinase-associated lipocalin (NGAL), and interleukin 6 (IL-6). The prognostic effect was evaluated after 2 weeks of treatment.

RESULTS

After mild hypothermia treatment after craniotomy and decompression, the patients' serum S100-β, sST2, NGAL, and IL-6 levels at different time points were significantly lower than the control group, and the total effective rate was higher than that of the control group.

CONCLUSION

The treatment of mild hypothermia after craniotomy can reduce the related organs function damage indicators and inflammatory stress response, thus improving clinical efficacy and prognosis.

Comparison of a bolt-connected external ventricular drain with a tunneled external ventricular drain - a narrative review and meta-analysis

External ventricular drain (EVD) is one of the most commonly performed neurosurgical procedures. EVD can be associated with high rates of complications like misplacement, iatrogenic hemorrhage, and CSF infection. Several modifications have been proposed in the EVD insertion techniques to decrease the risk of these complications. Bolt-connected EVD, one of these modifications which involves insertion of a bolt in the burr hole, has been proposed to have better chances of optimal placement of EVD tip, lesser risk of CSF infection, and accidental pullout. A comprehensive search of different databases was performed to retrieve studies comparing the bolt-connected EVD with tunneled EVD and meta-analysis was done. Seven studies met inclusion criteria and were included in the meta-analysis. Our analysis revealed that bolt-connected EVD is associated with significantly better chances of optimal placement than traditional tunneled EVD (MH OR-1.65, 95% CI 1.14 to 2.40, p = 0.008). We also observed that bolt-connected EVD is associated with significantly decreased risk of CSF infection (MH OR-0.60, 95% CI 0.39 to 0.94, p = 0.026), EVD malfunction (MH OR-0.31, 95% CI 0.16 to 0.58, p = 0.0003), and accidental disconnection (MH OR-0.09, 95% CI 0.03 to 0.26, p < 0.0001) as compared to traditional tunneled EVD. The difference between the two techniques was not statistically significant for complications, multiple punctures done for insertion of EVD, iatrogenic intracranial, and need of reoperation. Bolt-connected external ventricular drain is associated with significantly more chances of optimal placement and lesser chances of accidental discontinuation and CSF infection than tunneled EVD. There was no statistically significant difference noted between the two techniques for multiple punctures done for insertion of EVD, iatrogenic intracranial hemorrhage and need of reoperation. However, most of the included studies were retrospective. Thus, the results from the meta-analysis should be interpreted with caution as further prospective high-quality studies are needed.

Efficacy of a Novel Prophylactic Barbiturate Therapy for Severe Traumatic Brain Injuries: Step-down Infusion of a Barbiturate with Normothermia

This study aimed to examine the beneficial effects of a novel prophylactic barbiturate therapy, step-down infusion of barbiturates, using thiamylal with normothermia (NOR+sdB), on the poor outcome in the patients with severe traumatic brain injuries (sTBI), in comparison with mild hypothermia (MD-HYPO). From January 2000 to March 2019, 4133 patients with TBI were admitted to our hospital. The inclusion criteria were: a Glasgow coma scale (GCS) score of ≤8 on admission, age between 20 and 80 years, intracranial hematoma requiring surgical evacuation of the hematoma with craniotomy and/or external decompression, and patients who underwent management of body temperature and assessed their outcome at 6-12 months. Finally, 43 patients were included in the MD-HYPO (n = 29) and NOR+sdB (n = 14) groups. sdB was initiated intraoperatively or immediately after the surgical treatment. There were no significant differences in patient characteristics, including age, sex, past medical history, GCS on admission, type of intracranial hematoma, and length of hospitalization between the two groups. Although NOR+sdB could not improve the patient's poor outcome either at discharge from the intensive care unit (ICU) or at 6-12 months after admission, the treatment inhibited composite death at discharge from the ICU. The mean value of the maximum intracranial pressure (ICP) in the NOR+sdB group was <20 mmHg throughout the first 120 h. NOR+sdB prevented composite death in the ICU in patients with sTBI, and we may obtain novel insights into the beneficial role of prophylactic barbiturate therapy from suppression of the elevated ICP during the first 120 h.