J.-F. Payen

Trauma network for severely injured patients

Survival after severe trauma may depend on a structured chain of care from the management at the scene of trauma to hospital care and rehabilitation. In the USA, the trauma system is organized according to a pre-hospital triage by paramedics to facilitate the admission of patients to tertiary trauma centres. In France, trauma patients are transported to the most suitable facility, according to the on-scene triage by an emergency physician. Because French hospitals resources become scarce and expensive, the access to all techniques of resuscitation after severe trauma is restricted to tertiary trauma centres, at the expense of prolonged duration of transfer to these centres with a possible impact on mortality. The Northern French Alps Emergency Network created a regional trauma network system in 2008. This organization was based upon the interplay between the resources of each hospital participating to the network and the categorization of trauma severity at the scene. A regional registry allows the assessment of trauma system, which has included 3,690 severe trauma patients within the past 3 years. Bystanders, medical call dispatch centres, and interdisciplinary trauma team should form a structured and continuous chain of care to allocate each severe trauma patient to the best place of treatment.

Impact of a trauma network on mortality in patients with severe pelvic trauma

AIM To evaluate the impact of a regional trauma network on intra-hospital mortality rates of patients admitted with severe pelvic trauma. STUDY Retrospective observational study. PATIENTS Sixty-five trauma patients with serious pelvic fracture (pelvic abbreviated injury scale [AIS] score of 3 or more). METHODS Demographic, physiologic and biological parameters were recorded. Observed mortality rates were compared to predicted mortality according to the Trauma Revised Injury Severity Score methodology adjusted by a case mix variation model. RESULTS Twenty-nine patients were admitted in a level I trauma centre (reference centre) and 36 in level II trauma centres (centres with interventional radiology facility and/or neurosurgery). Patients from the level I trauma centre were more severely injured than those who were admitted at the level II trauma centres (Injury Severity Score [ISS]: 30 [13-75] vs 22 [9-59]; P<0.01). Time from trauma to hospital admission was also longer in level I trauma centre (115 [50-290] min vs 90 [28-240] min, P <0.01). Observed mortality rates (14%; 95% confidence interval, 95% CI, [1-26%]) were lower than the predicted mortality (29%; 95% CI [13-44%]) in the level I trauma centre. No difference in mortality rates was found in the level II trauma centres. CONCLUSION The regional trauma network could screen the most severely injured patients with pelvic trauma to admit them at a level I trauma centre. The observed mortality of these patients was lower than the predicted mortality despite increased time from trauma to admission.

Neurosédation en réanimation

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.

Évaluation prospective d'un score RMN dans le dépistage de la sensibilité à l'hyperthermie maligne. Résultats préliminaires

A prospective study for the noninvasive diagnosis of malignant hyperthermia (MH) susceptibility was conducted in 30 patients using 31P magnetic resonance spectroscopy (MRS). A score of MRS muscle abnormalities was determined before the in vitro contracture test. The patients were classified as MH susceptible or MH negative, according to an algorithm of MRS score values. Twenty-three patients were correctly classified using the MRS test, five had inclusive MRS score values and two patients were false-positive. There were no false-negative patients. These preliminary results suggest that the MRS test could be useful as a possible noninvasive diagnostic test in MH susceptibility.

Monitorage par spectroscopie de proche infrarouge en neuroréanimation

Near infrared spectroscopy (NIRS) can noninvasively measure cerebral saturation in oxygen, that permits to estimate brain oxygenation and metabolism. This technique could be incorporated into a multimodal monitoring for severely brain-injured patients. This review presents the principles of NIRS, its limits, the main results from clinical studies and its perspectives. More clinical studies are needed before recommending the routine use of NIRS in the ICU.

Brain electrical activity during combined hypoxemia and hypoperfusion in anesthetized rats

In order to investigate the effects of moderate hypoxemia on brain electrical activity and the consequences of an altered cerebro-vascular response to hypoxemia, we recorded changes in electrical activity of the brain in anesthetized rats following unilateral carotid artery ligation (UCAL). In these animals, on the clamped side, cerebral blood flow, whilst normal during normoxia, shows less augmentation during hypoxemia. Six anesthetized (Halothane) Sprague-Dawley rats with UCAL were studied during 20 min periods of baseline (FI(O(2))=30%), hypoxemia (FI(O(2))=9.5%) and recovery (FI(O(2))=30%): mean arterial pressure of oxygen (PA(O(2))) achieved was 177.0, 37.6 and 160.1 mmHg, respectively. A significant decrease in the frequencies of the ECoG was observed bilaterally during hypoxemia: centroid frequency (fc)=3.37+/-0.14 and 2.85+/-0.13 Hz on the intact and clamped hemisphere respectively during hypoxemia versus fc=4.09+/-0.20 Hz (mean+/-S.E.M.) during baseline, which was not reversed during recovery (3.27+/-0.11 Hz) (ANOVA, P<0.01). The total power of the signal (Pw) was unaffected on the intact hemisphere but diminished on the clamped side during hypoxemia. Our results show that a significant slowing of ECoG is observed during hypoxemia of moderate intensity (40 mmHg) even when cerebro-vascular response to hypoxemia is preserved and that total power of the ECoG signal is severely diminished when the cerebro-vascular response to hypoxemia is impaired.