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(RSS) Trauma Research Blog

Selected new & juicy research papers, with editorial comment.

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Trauma Research Blog

Selected new & juicy research papers, with editorial comment.

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PubMed ID: 21107105
Ann Surg. 2010 Dec;252(6):959-65.
Authors: Bernard SA, Nguyen V, Cameron P, Masci K, Fitzgerald M, Cooper DJ, Walker T, Std BP, Myles P, Murray L, David, Taylor, Smith K, Patrick I, Edington J, Bacon A, Rosenfeld JV, Judson R.

Abstract:

OBJECTIVE: To determine whether paramedic rapid sequence intubation in patients with severe traumatic brain injury (TBI) improves neurologic outcomes at 6 months compared with intubation in the hospital.

BACKGROUND: Severe TBI is associated with a high rate of mortality and long-term morbidity. Comatose patients with TBI routinely undergo endo-tracheal intubation to protect the airway, prevent hypoxia, and control ventilation. In many places, paramedics perform intubation prior to hospital arrival. However, it is unknown whether this approach improves outcomes.

METHODS: In a prospective, randomized, controlled trial, we assigned adults with severe TBI in an urban setting to either prehospital rapid sequence intubation by paramedics or transport to a hospital emergency department for intubation by physicians. The primary outcome measure was the median extended Glasgow Outcome Scale (GOSe) score at 6 months. Secondary end-points were favorable versus unfavorable outcome at 6 months, length of intensive care and hospital stay, and survival to hospital discharge.

RESULTS: A total of 312 patients with severe TBI were randomly assigned to paramedic rapid sequence intubation or hospital intubation. The success rate for paramedic intubation was 97%. At 6 months, the median GOSe score was 5 (interquartile range, 1-6) in patients intubated by paramedics compared with 3 (interquartile range, 1-6) in the patients intubated at hospital (P = 0.28).The proportion of patients with favorable outcome (GOSe, 5-8) was 80 of 157 patients (51%) in the paramedic intubation group compared with 56 of 142 patients (39%) in the hospital intubation group (risk ratio, 1.28; 95% confidence interval, 1.00-1.64; P = 0.046). There were no differences in intensive care or hospital length of stay, or in survival to hospital discharge.

CONCLUSIONS: In adults with severe TBI, prehospital rapid sequence intubation by paramedics increases the rate of favorable neurologic outcome at 6 months compared with intubation in the hospital.

Notes & Commentary:

This well designed, conducted and reported randomised controlled trial (RCT) of prehospital rapid sequence induction (RSI) of anaesthesia & intubation in traumatic brain injury is the first RCT of prehospital RSI of any reasonable quality in trauma.  (See the 2009 Cochrane Review "Emergency intubation for acutely ill and injured patients").  Furthermore the researchers moved beyond mortality as the primary outcome to a more comprehensive assessment of outcome (dependency).  They found no difference in hospital outcomes but a strong signal for "good neurological outcome" (normal to moderate disability) in the Prehospital RSI group.

Overall the study was well conducted.  Subjects were block randomised by paramedic crew via sealed opaque envelopes.  The study was conducted over nearly four years.  There were a lot of exclusions - 1045 patients were screened but only 312 enrolled.  Most exclusions were either because the patient was being transported by air, was less than 10 minutes from hospital or RSI skills were not available at scene.

As with all such studies there are many questions to answer.  Despite the observed outcome differences, there was little difference in the 2 groups on hospital arrival, and in particular there was no difference in their PaO2, O2 saturations or PaCO2 measurements.  What then was the benefit of prehospital RSI - does it avoid fluctuations in these variables or is it reducing spikes in intracranial pressure? The preshopital RSI patients statistically spent 12 minutes longer on scene, received approximately 500mls more crystalloid prehospitally, and were colder (by 0.6 degrees C).  Is the observed effect due to the protective effects of this mild relative hypothermia (mean 35.0 degrees C).

Additionally there was overall benefit but it was not clear which subgroup had the most benefit from prehospital RSI.  There was a trend to suggest that those age <60 received the most benefit.  However the trial was really too small for these subgroup analyses and none of the reported subgroups showed worse outcomes with the study intervention.  This study joins the list of recent studies showing that good quality clinical trials can be conducted in trauma care, even in the prehospital environment.  There is really no longer any excuse for poor design, conduct or reporting of trauma trials.  While a further large trial is warranted, this is strong support for prehospital RSI. 

PubMed ID: 19627946
PM R. 2009 Jun;1(6):560-75
Authors: Devine JM, Zafonte RD.

Abstract:

OBJECTIVE: Physical exercise has been shown to play an ever-broadening role in the maintenance of overall health and has been implicated in the preservation of cognitive function in both healthy elderly and demented populations. Animal and human studies of acquired brain injury (ABI) from trauma or vascular causes also suggest a possible role for physical exercise in enhancing cognitive recovery. DATA SOURCES: A review of the literature was conducted to explore the current understanding of how physical exercise impacts the molecular, functional, and neuroanatomic status of both intact and brain-injured animals and humans. STUDY SELECTION: Searches of the MEDLINE, CINHAL, and PsychInfo databases yielded an extensive collection of animal studies of physical exercise in ABI. Animal studies strongly tie physical exercise to the upregulation of multiple neural growth factor pathways in brain-injured animals, resulting in both hippocampal neurogenesis and functional improvements in memory. DATA EXTRACTION: A search of the same databases for publications involving physical exercise in human subjects with ABI yielded 24 prospective and retrospective studies. DATA SYNTHESIS: Four of these evaluated cognitive outcomes in persons with ABI who were involved in physical exercise. Three studies cited a positive association between exercise and improvements in cognitive function, whereas one observed no effect. Human exercise interventions varied greatly in duration, intensity, and level of subject supervision, and tools for assessing neurocognitive changes were inconsistent. CONCLUSIONS: There is strong evidence in animal ABI models that physical exercise facilitates neurocognitive recovery. Physical exercise interventions are safe in the subacute and rehabilitative phases of recovery for humans with ABI. In light of strong evidence of positive effects in animal studies, more controlled, prospective human interventions are warranted to better explore the neurocognitive effects of physical exercise on persons with ABI.

Notes & Commentary:

PubMed ID: 19479650
Ultrastruct Pathol. 2009;33(3):102-11
Authors: Castejon OJ

Abstract:

In a vascular anomaly showing moderate edema, the extracellular space appeared apparently normal, exhibiting a membrane to membrane space of about 20 nm in width. In congenital hydrocephalus, this space appeared notably enlarged and occupied by an electron transparent, nonproteinaceous interstitial edema fluid, due to abnormal accumulation of cerebrospinal fluid. In brain trauma, the distended extracellular space contained either electron-lucid nonproteinaceous or electron-dense proteinaceous edema fluid. Hemorrhagic foci, fibrinoid material, and non-nervous invading cells, such as macrophages and monocytes, were also found. In brain tumors, the widened extracellular space showed electron-dense proteinaceous edema fluid and bundles of fibrinoid material. The enlarged extracellular space found in congenital hydrocephalus, vascular anomalies, brain trauma, and tumors is closely related to the clinical symptoms exhibited by the patients under study.

Notes & Commentary:

How simplistic our clinical view of traumatic brain injury is.  We think only of intracranial pressure, perfusion pressure, and cerebral oxygen delivery & utilization.  We understand cerebral oedema only as a hydrostatic effect to be treated with osmotic therapy.  This study shows that cerebral oedema in traumatic brain injury is far from a simple fluid shift but is instead a complex phenomenon, probably containing a complex of proinflammatory and coagulant mediators of the innate immune system.  We need to rapidly develop a more complex approach to our clinical understanding of these injuries if we are to make any progress in their management - progress which has been relatively disappointing over the past few decades.

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