A clinical prediction model for raised intracranial pressure in patients with traumatic brain injuries

Diagnosis and management of elevated intracranial pressure in the emergency department

BACKGROUND

Elevated intracranial pressure is a devastating complication of catastrophic brain injury. Intracranial hypertension is commonly seen in neurologic injury secondary to traumatic brain injuries. Uncontrolled pressures can lead to permanent neurologic damage, but acute medical management is often overlooked when pursuing surgical management options that may not always be indicated.

DISCUSSION

Traumatic brain injury is the leading cause of death in patients with severe neurologic injury. Diagnosing elevated intracranial pressures is imperative in initiating prompt treatment to reduce secondary central nervous system injury, morbidity, and mortality. Although the initial injury to the brain is typically irreversible, intracranial pressure control can assist in salvaging the remaining brain tissue from additional damage. We will discuss the initial medical and surgical management of traumatic brain injury to prevent further neurologic deterioration and reduce mortality.

CONCLUSION

Recent literature has reported several methods to detect elevated intracranial pressure easily and studies describing multiple treatment modalities. These investigations suggest that early detection and timely treatment of intracranial hypertension are beneficial in reducing mortality.

Relationship of Optic Nerve Sheath Diameter and Intracranial Hypertension in Patients with Traumatic Brain Injury

Background

to study the association between optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in patients with moderate-to-severe brain injury.

Patients and Methods

A retrospective cohort study of traumatic brain injury (TBI) patients was conducted between 2010 and 2014. Data were analyzed and compared according to the ICP monitoring cutoff values. Outcomes included intracranial hypertension (ICH) and mortality.

Results

A total of 167 patients with a mean age of 33 ± 14 years, of them 96 had ICP monitored. ICP values correlated with ONSD measurement (r = 0.21, P = 0.04). Patients who developed ICH were more likely to have higher mean ONSD (P = 0.01) and subarachnoid hemorrhage (SAH) (P = 0.004). Receiver operating curve for ONSD showed a cutoff value of 5.6 mm to detect ICH with sensitivity 72.2% and specificity 50%. Age and ICP were independent predictors of inhospital mortality in multivariate model. Another model with same covariates showed ONSD and SAH to be independent predictors of ICH. Simple linear regression showed a significant association of ONSD with increased ICP (β = 0.21, 95% confidence interval 0.25-5.08, P = 0.03).

Conclusions

ONSD is a simple noninvasive measurement on initial CT in patients with TBI that could be a surrogate for ICP monitoring. However, further studies are warranted.

Forecasting intracranial hypertension using multi-scale waveform metrics

OBJECTIVE

Acute intracranial hypertension is an important risk factor of secondary brain damage after traumatic brain injury. Hypertensive episodes are often diagnosed reactively, leading to late detection and lost time for intervention planning. A pro-active approach that predicts critical events several hours ahead of time could assist in directing attention to patients at risk.

APPROACH

We developed a prediction framework that forecasts onsets of acute intracranial hypertension in the next 8 h. It jointly uses cerebral auto-regulation indices, spectral energies and morphological pulse metrics to describe the neurological state of the patient. One-minute base windows were compressed by computing signal metrics, and then stored in a multi-scale history, from which physiological features were derived.

MAIN RESULTS

Our model predicted events up to 8 h in advance with an alarm recall rate of 90% at a precision of 30% in the MIMIC-III waveform database, improving upon two baselines from the literature. We found that features derived from high-frequency waveforms substantially improved the prediction performance over simple statistical summaries of low-frequency time series, and each of the three feature classes contributed to the performance gain. The inclusion of long-term history up to 8 h was especially important.

SIGNIFICANCE

Our results highlight the importance of information contained in high-frequency waveforms in the neurological intensive care unit. They could motivate future studies on pre-hypertensive patterns and the design of new alarm algorithms for critical events in the injured brain.

Diagnosis of elevated intracranial pressure in critically ill adults: systematic review and meta-analysis

OBJECTIVES

To summarise and compare the accuracy of physical examination, computed tomography (CT), sonography of the optic nerve sheath diameter (ONSD), and transcranial Doppler pulsatility index (TCD-PI) for the diagnosis of elevated intracranial pressure (ICP) in critically ill patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Six databases, including Medline, EMBASE, and PubMed, from inception to 1 September 2018.

STUDY SELECTION CRITERIA

English language studies investigating accuracy of physical examination, imaging, or non-invasive tests among critically ill patients. The reference standard was ICP of 20 mm Hg or more using invasive ICP monitoring, or intraoperative diagnosis of raised ICP.

DATA EXTRACTION

Two reviewers independently extracted data and assessed study quality using the quality assessment of diagnostic accuracy studies tool. Summary estimates were generated using a hierarchical summary receiver operating characteristic (ROC) model.

RESULTS

40 studies (n=5123) were included. Of physical examination signs, pooled sensitivity and specificity for increased ICP were 28.2% (95% confidence interval 16.0% to 44.8%) and 85.9% (74.9% to 92.5%) for pupillary dilation, respectively; 54.3% (36.6% to 71.0%) and 63.6% (46.5% to 77.8%) for posturing; and 75.8% (62.4% to 85.5%) and 39.9% (26.9% to 54.5%) for Glasgow coma scale of 8 or less. Among CT findings, sensitivity and specificity were 85.9% (58.0% to 96.4%) and 61.0% (29.1% to 85.6%) for compression of basal cisterns, respectively; 80.9% (64.3% to 90.9%) and 42.7% (24.0% to 63.7%) for any midline shift; and 20.7% (13.0% to 31.3%) and 89.2% (77.5% to 95.2%) for midline shift of at least 10 mm. The pooled area under the ROC (AUROC) curve for ONSD sonography was 0.94 (0.91 to 0.96). Patient level data from studies using TCD-PI showed poor performance for detecting raised ICP (AUROC for individual studies ranging from 0.55 to 0.72).

CONCLUSIONS

Absence of any one physical examination feature is not sufficient to rule out elevated ICP. Substantial midline shift could suggest elevated ICP, but the absence of shift cannot rule it out. ONSD sonography might have use, but further studies are needed. Suspicion of elevated ICP could necessitate treatment and transfer, regardless of individual non-invasive tests.

REGISTRATION

PROSPERO CRD42018105642.

Clinical Predictors for Unsafe Direct Discharge Home Patients From Intensive Care Units

PURPOSE

To describe factors (demographics and clinical characteristics) that predict patients who are at an increased risk of adverse events or unplanned return visits to a health-care facility following discharge direct to home (DDH) from intensive care units (ICUs).

METHODS

Prospective cohort study of all adult patients who survived their stay in our medical-surgical-trauma ICU between February 2016 and 2017 and were discharged directly home. Patients were followed for 8 weeks postdischarge. Univariable and multivariable logistic regression analyses were performed to identify factors associated with adverse events or unplanned return visits to a health-care facility following DDH from ICU.

RESULTS

A total of 129 DDH patients were enrolled and completed the 8-week follow-up. We identified 39 unplanned return visits (URVs). There was 0% mortality at 8 weeks postdischarge. Eight potential predictors of hospital URVs (P < .2) were identified in the univariable analysis: prior substance abuse (odds ratio [OR] of URV of 2.50 [95% confidence interval: 1.08-5.80], hepatitis (OR: 6.92 [1.68-28.48]), sepsis (OR: 11.03 [1.19-102.29]), admission nine equivalents of nursing manpower score (NEMS) <24 (OR: 2.28 [1.03-5.04], no fixed address (OR: 22.9 [1.2-437.3]), ICU length of stay (LOS) <2 days (OR: 2.95 [1.28-6.78]), home discharge within London, Ontario (OR: 2.44 [1.00-5.92]), and left against medical advice (AMA; OR: 6.06 [2.04-17.98]).

CONCLUSIONS

Our study identified 8 covariates that were potential predictors of URV: prior substance abuse, hepatitis, sepsis, admission NEMS <24, no fixed address, ICU LOS <2 days, home discharge within London, Ontario, and left AMA. The practice of direct discharges home from the ICU would benefit from adequately powered multicenter study in order to construct a clinical prediction model (that would require further testing and validation).