Category Archives: Trauma

Care of severely injured patient

Ad hoc resus teams less effective

During simulated cardiac arrest resuscitations, a comparision was made between those run by teams that had had time to form before the arrest, and those that had to be assembled ad hoc after the arrest occurred. 99 teams of three doctors, including GPs and hospital physicians were studied. ACLS algorithms were less closely followed in the ad hoc formed teams, with more delays to therapies such as defibrillation. Analysis of voice recordings revealed the ad hoc teams to make fewer leadership utterances (eg. ‘we should defibrillate’ or ‘the next countershock will be 360J’) and more reflective utterances (eg. ‘what should we do next?’). The authors suggest that team building is therefore to be regarded as an additional task imposed on teams formed ad hoc during CPR that may substantially impact on outcome. No surprise to those of us who banned ‘cardiac arrest teams’ from our emergency department resuscitation rooms many years ago!

 

Hands-on time during cardiopulmonary resuscitation is affected by the process of teambuilding: a prospective randomised simulator-based trial

BMC Emerg Med. 2009 Feb 14;9:3

http://www.ncbi.nlm.nih.gov/pubmed/19216796

Full text at http://www.biomedcentral.com/1471-227X/9/3

Tibial vs humeral intraosseous approaches

An observational, prospective study comparing tibial and humeral intraosseous access using the EZ-IO

Emergency physicians at Singapore General Hospital found flow rates to be similar when comparing the tibia with the humerus as sites for adult IO access. The EZ-IO had a very high insertion success rate. It took about 12 minutes to infuse a litre of saline, which drops to about 6 minutes if a pressure bag is used.

Am J Emerg Med. 2009 Jan;27(1):8-15

http://www.ncbi.nlm.nih.gov/pubmed/19041528

Fluid Flow Through Intravenous Cannulae

Published flow rates for cannulae are derived from a test in which fluid runs through a perfectly straight cannula into an open receptacle. Laminar flow is expected in such a model in which the Hagen-Poisseuille formula tells us that flow is proportional to the fourth power of the radius. In this study manufacturers’ published flow rates were compared with an artifical vein model. Hartmann’s flowed faster than Gelofusine. For all cannulas flow was less than the manufacturers’ published rates. Although the radius was the biggest determinant of flow rate, the fourth power could not be used, suggesting a mixture of laminar and turbulent flow. The addition of pressurised infusions increased the flow rate with increasing pressure. Although the vein model used has limitations, and many other factors may influence flow rate in the clinical setting, the authors’ conclusions are helpful:

While the effect of radius is less than commonly believed, it is still important. However, clinicians should be aware of the limitations of increasing radius and use other strategies to increase flow when needed. These could include use of pressure, choice of fluid to be infused, and using multiple cannulae in parallel.

Fluid flow through intravenous cannulae in a clinical model
Anesth Analg. 2009 Apr;108(4):1198-202

High BMI and frontal crashes

In adult patients injured in front impact motor vehicle collisions, the outcomes of obese patients with a Body Mass Index greater than 30 kg/m2 was compared with those less than 30 kg/m2. Obese patients were more likely to suffer a severe head injury from a frontal collision.

J Trauma. 2009 Mar;66(3):727-9
Traumatic Brain Injury After Frontal Crashes: Relationship With Body Mass Index

ETCO2 all over the place in trauma

In 180 intubated trauma patients in the ED, there was little correlation between arterial carbon dioxide tension (PaCO2) and end-tidal carbon dioxide levels (ETCO2) (R2 = 0.277). In fact, in those patients ventilated to the ‘normal range’ of 35-40 mmHg (4.6-5.2 kPa), PaCO2 was over 50 mmHg 30% of the time. Slightly reassuring that in isolated brain injury the correlation was better (r2 = 0.52)

The Utility of Early End-Tidal Capnography in Monitoring Ventilation Status After Severe Injury
J Trauma. 2009 Jan;66(1):26-31

Blood product ratios and survival bias

Haemostatic resuscitation of trauma patients, using high ratios of fresh frozen plasma (FFP) to packed red cells (PRBC), is growing in popularity as a result of military experience. Few data support the practice in civilian trauma. It is possible that some of the demonstrated mortality benefit is a result of survival bias: it takes time to obtain FFP, by which time severely injured patients may be dead. Therefore, those that receive large ratios of FFP:PRBC must have survived long enough to receive it. In other words FFP doesn’t lead to survival, but survival leads to FFP. Some evidence in favour of this explanation is provided on a study of 134 patients in the Journal of Trauma. Reanalysing data to correct for survival bias made an apparently significant survival benefit from high FFP:PRBC ratios go away. An interesting paper, although unlikely to dissuade us from paying attention to coagulopathy in trauma. I suspect the debate on optimal blood product resuscitation will be around for a while.

The Relationship of Blood Product Ratio to Mortality: Survival Benefit or Survival Bias?
J Trauma. 2009 Feb;66(2):358-62

Sodium lactate for raised ICP

Lactate may be an important metabolic substrate for injured brain and sodium lactate may have beneficial effects on cerebral oedema and cerebral blood flow. Sodium lactate was compared with 20% mannitol in severely brain injured patients with cranial hypertension in a randomised controlled trial. Sodium lactate was more likely to lower ICP, and to have a sustained effect on ICP. A nonsignificant improvement in one year outcome was seen with sodium lactate, although the study was not powered for this endpoint. These promising findings should prompt a larger multicentre study.

Sodium lactate versus mannitol in the treatment of intracranial hypertensive episodes in severe traumatic brain-injured patients
Intensive Care Med. 2009 Mar;35(3):471-9

Passenger Compartment Intrusion and Kids

The presence and degree of compartment intrusion (from crash investigation data) was correlated with the likelihood of serious injury in 880 children from age 0-15 years, and odds for presence of serious injury increased for each centimetre of compartment intrusion.

Passenger Compartment Intrusion as a Predictor of Significant Injury for Children in Motor Vehicle Crashes
J Trauma. 2009 Feb;66(2):504-7

Whole body CT in trauma

German trauma patients are more likely to survive if they have a whole body CT rather than selective scans. Or that’s what this paper would have you believe IF you’re happy with the retrospective comparison, multivariate adjustments, and potential confounders. Still, if it helps you get your radiologists to play ball, the reference is…

Effect of whole-body CT during trauma resuscitation on survival: a retrospective, multicentre study
Lancet. 2009 Apr 25;373(9673):1455-61

Rectal exam has lousy test characteristics

A comprehensive review of the literature, the findings of which showed ‘compelling’ consistency: digital rectal examination (DRE) as a screening test had sensitivities ranging from 0% to 50%, had consistently high false-positive and false-negative rates, and did not improve the predictive value of the other components of a typical trauma examination.

Based on case reports of five patients, the authors suggest DRE may be of value during trauma evaluation in the following settings: (1) patients with evidence of penetrating trauma in the vicinity of the rectum, (2) cases in which the presence of neurologic injury is neither completely supported nor refuted by the clinical findings, and (3) before pharmacologic paralysis. A selective approach is therefore recommended. Some good news for your patients if this will persuade you to discard another piece of longstanding dogma perpetuated in basic trauma teaching.

Should the digital rectal examination be a part of the trauma secondary survey?
Ann Emerg Med. 2009 Feb;53(2):208-12