A systematic review of pre-hospital intubation for head injured patients failed to show evidence of benefit of tracheal intubation or invasive ventilation. The authors acknowledge the lack of methodological quality in the studies reviewed and the predominance of US paramedic-delivered intubations without the use of anaesthetic drugs.
Pre-hospital tracheal intubation in patients with traumatic brain injury: systematic review of current evidence
Br J Anaesth. 2009 Sep;103(3):371-86
Of 203 patients attending a US Level 1 trauma centre who had pre-hospital airway management, 25 (12%) had unrecognised oesophageal intubations.
Patients were treated in the field by fire rescue personnel of various municipalities and with different experience levels. Patients transported by air were significantly more likely to be successfully intubated than those transported by ground, perhaps due to both increased experience and the use by air crews of succinylcholine. The authors in their discussion contrast these results with those of European studies which report higher success rates with pre-hospital systems that employ emergency physicians and anaesthetists.
Prehospital intubations and mortality: a level 1 trauma center perspective
Anesth Analg. 2009 Aug;109(2):489-93
Vehicle rollover as an indicator of mechanism of injury was investigated in a study examining accident databases and the medical literature. Only 2.4% of crashes involved rollovers but they accounted for one third of occupant deaths.
Some facts on vehicle rollover from the article:
The importance of vehicle rollover as a field triage criterion
J Trauma. 2009 Aug;67(2):350-7
The Canadian C-Spine rule – a decision instrument designed to clinically rule out important cervical spine injuries in alert patients – was successfully and safely applied by Canadian paramedics in a study of 1949 patients. Any misinterpretation erred on the side of safety.
This important work could ultimately result in less stress, discomfort, and wasting of ambulance resources and time for this large subgroup of pre-hospital patients.
The Out-of-Hospital Validation of the Canadian C-Spine Rule by Paramedics
Ann Emerg Med. 2009 Nov;54(5):663-671
A prospective study of 746 children sedated in the emergency department with iv or im ketamine revealed 2.1% may have experienced ’emergence delirium’ although the authors concede this was difficult to define. In contrast, 291 (38%) reported pleasant altered perceptions. Follow up revealed at least one nightmare in the following weeks in 3.4% of patients, which may be well under the rate reported in the normal unsedated paediatric population.
What is the nature of the emergence phenomenon when using intravenous or intramuscular ketamine for paediatric procedural sedation?
Emerg Med Australas. 2009 Aug;21(4):315-22
Finally a well designed blinded randomised controlled trial on this subject. 0.3 mg/kg etomidate was compared with 2mg/kg ketamine for RSI in 655 patients requiring emergency intubation in the pre-hospital, emergency department, or intensive care unit environments. No difference was observed in intubation conditions or the primary endpoint of maximum SOFA score in the first three days, although the etomidate group had a higher rate of adrenal insufficiency as defined by response to an ACTH test.
Etomidate versus ketamine for rapid sequence intubation in acutely ill patients: a multicentre randomised controlled trial.
Lancet. 2009 Jul 25;374(9686):293-300
Plasma levels of adrenaline and noradrenaline increased signficantly in patients with acute coronary syndrome during ambulance transportation – a finding in keeping with studies on normal volunteers. I wonder how much more of an effect helicopter retrieval might have?
Emergency ambulance transport induces stress in patients with acute coronary syndrome
Emerg Med J. 2009 Jul;26(7):524-8.
Ketamine lowered ICP in brain-injured kids
Ventilated children between the ages of 1 and 16 with traumatic brain injury and elevated intracranial pressure (ICP) were given ketamine and effect on cerebral perfusion pressure (CPP) and ICP was measured. Ketamine decreased ICP while maintaining blood pressure and CPP.
These results refute the notion that ketamine increases ICP. The authors conclude: “Ketamine is a safe and effective drug for patients with traumatic brain injury and intracranial hypertension, and it can possibly be used safely in trauma emergency situations”
Effectiveness of ketamine in decreasing intracranial pressure in children with intracranial hypertension
J Neurosurg Pediatr. 2009 Jul;4(1):40-6 (Full text)
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
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