[Sedation and analgesia for the brain-injured patient]

Development of a mobile low-field MRI scanner

Magnetic resonance imaging (MRI) allows important visualization of the brain and central nervous system anatomy and organization. However, unlike electroencephalography (EEG) or functional near infrared spectroscopy, which can be brought to a patient or study participant, MRI remains a hospital or center-based modality. Low magnetic field strength MRI systems, however, offer the potential to extend beyond these traditional hospital and imaging center boundaries. Here we describe the development of a modified cargo van that incorporates a removable low-field permanent magnet MRI system and demonstrate its proof-of-concept. Using phantom scans and in vivo T₂-weighted neuroimaging data, we show no significant differences with respect to geometric distortion, signal-to-noise ratio, or tissue segmentation outcomes in data acquired in the mobile system compared to a similar static system in a laboratory setting. These encouraging results show, for the first time, MRI that can be performed at a participant’s home, community center, school, etc. Breaking traditional barriers of access, this mobile approach may enable imaging of patients and participants who have mobility challenges, live long distances from imaging centers, or are otherwise unable to travel to an imaging center or hospital.

General intensive care for patients with traumatic brain injury: An update

Background:

Traumatic brain injury (TBI) is a growing epidemic throughout the world and may present as major global burden in 2020. Some intensive care units throughout the world still have no access to specialized monitoring methods, equipments and other technologies related to intensive care management of these patients; therefore, this review is meant for providing generalized supportive measurement to this subgroup of patients so that evidence based management could minimize or prevent the secondary brain injury.

Methods:

Therefore, we have included the PubMed search for the relevant clinical trials and reviews (from 1 January 2007 to 31 March 2013), which specifically discussed about the topic.

Results:

General supportive measures are equally important to prevent and minimize the effects of secondary brain injury and therefore, have a substantial impact on the outcome in patients with TBI. The important considerations for general supportive intensive care unit care remain the prompt reorganization and treatment of hypoxemia, hypotension and hypercarbia. Evidences are found to be either against or weak regarding the use of routine hyperventilation therapy, tight control blood sugar regime, use of colloids and late as well as parenteral nutrition therapy in patients with severe TBI.

Conclusion:

There is also a need to develop some evidence based protocols for the health-care sectors, in which there is still lack of specific management related to monitoring methods, equipments and other technical resources. Optimization of physiological parameters, understanding of basic neurocritical care knowledge as well as incorporation of newer guidelines would certainly improve the outcome of the TBI patients.

Aerosolized lidocaine during invasive mechanical ventilation: in vitro characterization and clinical efficiency to prevent systemic and cerebral hemodynamic changes induced by endotracheal suctioning in head-injured patients

BACKGROUND

In patients with severe brain injury, endotracheal suctioning (ETS) can increase intracranial pressure (ICP) and reduce cerebral perfusion pressure (CPP). The aim of this prospective, blinded clinical trial was to assess the effectiveness of aerosolized lidocaine to prevent increase of ICP induced by ETS in mechanically ventilated head-injured patients.

METHODS

First, we measured the particle size of aerosolized lidocaine produced by a vibrating plate nebulizer. Second, we measured the cerebral hemodynamic response to tracheal suctioning in patients in a neurosurgical intensive care unit with and without pretreatment of aerosolized lidocaine.

RESULTS

Particle size distribution of aerosolized lidocaine was suitable to reach the bronchotracheal target during mechanical ventilation. In 15 patients included in this study, aerosolized lidocaine by itself did not induce significant changes in ICP. ETS caused an increase in ICP (variation: 6±2 mm Hg, P<0.05) with a concomitant decrease in CPP (variation: 2±2 mm Hg, P<0.05) that was maximal at 1 minute after NaCl aerosolization. This was prevented by aerosolization of lidocaine (variation of ICP: 1±1 mm Hg, and CPP: -1±1 mm Hg, P<0.05).

CONCLUSIONS

Aerosolized lidocaine (2 mg/kg) can prevent ETS-induced increases in ICP, without modifying systemic and cerebral hemodynamics in deeply sedated patients.

Pain indicators in brain-injured critical care adults: an integrative review

INTRODUCTION

Health professionals are confronted with the difficulty of adequately evaluating pain in critically ill, brain-injured patients, as these patients are often unable to self-report. In addition, their confused and stereotyped behaviours may change their responses to pain; the indicators and descriptors generally used to evaluate pain in the critically ill may therefore not be appropriate for brain-injured patients.

AIM

The aim of this integrative review was to identify clinically measurable and observable pain indicators and descriptors for brain-injured, critically ill adults.

METHOD

A search of electronic databases (Medline, CINAHL, Embase) combined with cross-referencing was performed. Articles were included if they described pain indicators in critically ill adults and included brain-injured patients in their population.

RESULTS

Seven articles met the inclusion criteria. They were critically appraised for their quality and their relevance for the population of brain-injured patients. Behavioural pain indicators such as facial expressions, body movements and muscle tension were found in all of the articles. However, the descriptions of the indicators differ from one article to another. The intensity and nature of behavioural pain responses vary according to the level of consciousness. Changes in physiological parameters have also been reported, but these results are inconclusive.

CONCLUSION

Additional research is needed to identify and better describe pain indicators that are specific to brain-injured patients in the ICU. Studies with large samples, different brain injury diagnoses and various levels of consciousness are warranted.

[Sedation in neurointensive care unit]

The objectives for using sedation in neurointensive care unit (neuroICU) are somewhat different from those used for patients without severe brain injuries. One goal is to clinically reassess the neurological function following the initial brain insult in order to define subsequent strategies for diagnosis and treatment. Another goal is to prevent severely injured brain from additional aggravation of cerebral blood perfusion and intracranial pressure. Depending on these situations is the choice of sedatives and analgesics: short-term agents, e.g., remifentanil, if a timely neurological reassessment is required, long-term agents, e.g., midazolam and sufentanil, as part of the treatment for elevated intracranial pressure. In that situation, a multimodal monitoring is needed to overcome the lack of clinical monitoring, including repeated measurements of intracranial pressure, blood flow velocities (transcranial Doppler), cerebral oxygenation (brain tissue oxygen tension), and brain imaging. The ultimate stop of neurosedation can distinguish between no consciousness and an alteration of arousing in brain-injured patients. During this period, an elevation of intracranial pressure is usual, and should not always result in reintroducing the neurosedation.

[Superior vena cava syndrome: cause of secondary raise of intracranial pressure after traumatic brain injury]

A 41-year-old male is admitted for cranial trauma, having fallen from his own height. His state of extreme agitation imposes sedation, intubation and mechanical ventilation. A CT-scan reveals acute right hemispheric subdural haematoma, with discrete midline shift, and diffuse cerebral oedema. ICP-monitoring reveals severely increased intracranial pressure, which is responsive to routine medical neuroprotective treatment. Ten days after admission, sedation and neuroprotective treatment is gradually withdrawn. At the end of the second week, a secondary ascent in ICP is observed. The presence of a right subclavian central venous line, in combination with the strong inflammatory response and septic state of the patient, has caused bilateral thrombosis of subclavian and internal jugular veins. This superior vena cava syndrome (SVCS) impedes cerebral venous drainage, thus raising ICP. Within a few days of anticoagulant therapy, SVCS resolved. Impeded cerebral venous drainage is often forgotten or ignored as a cause of secondary elevated ICP. In face of persisting or recurring raised ICP and cerebral oedema, or apparition of communicant hydrocephalus, cerebral venous drainage should be investigated.