Pre-term infants lacking surfactant often require mechanical ventilation, but the consequent barotrauma and volutrauma may contribute to chronic lung disease, or bronchopulmonary dysplasia. Consequently high frequency oscillatory ventilation (HFOV) has been tried, but results from trials are mixed. A new systematic review of 3229 preterm newborns of less than 35 weeks’ gestation in 10 randomised trials fails to show a benefit of HFOV over conventional ventilation.
Elective high-frequency oscillatory versus conventional ventilation in preterm infants: a systematic review and meta-analysis of individual patients’ data
The Lancet, Volume 375, Issue 9731, Pages 2082 – 2091, 12 June 201o
Exsanguinating pelvis – occlude the aorta
Some patients with life-threatening arterial haemorrhage from a pelvic fracture may be peri-arrest prior to transfer to the angiography suite. French authors describe their use of a balloon catheter to occlude the infrarenal aorta to allow resuscitation to achieve sufficient stability for the transfer. As well as exsanguinating pelvic haemorrhage, intra-aortic balloon occlusion has already been described for the treatment of hemorrhagic shock in the case of ruptured abdominal aortic aneurysm, in abdominal trauma, in gastrointestinal bleeding, and in postpartum hemorrhage.
Features of note regarding the technique include:
- it can be done blind (without radiological guidance)
- it can be done prior to transfer to a centre with interventional radiology
- it can be done in cardiac arrest (and has resulted in ROSC and subsequent survival)
The authors are at pains to point out that the intra-aortic balloon occlusion method described in the study ‘should be reserved to patients in critically uncontrollable hemorrhagic shock (CUHS) and is not a first-line treatment of pelvic fractures in hemorrhagic shock.’
Intra-Aortic Balloon Occlusion to Salvage Patients With Life-Threatening Hemorrhagic Shocks From Pelvic Fractures
J Trauma. 2010 Apr;68(4):942-8.
Tranexamic acid saves lives in trauma
A convincing, practice-changing trial is a rare thing in major trauma, but here comes a biggie:
The CRASH-2 trial recruited over 20 000 patients from 40 countries (sadly excluding the US because the trial investigators couldn’t afford the insurance – a sign that no large drug company was funding this trial of an inexpensive therapy).
The antifibrinolytic drug tranexamic acid was compared with placebo in adult trauma patients with, or thought to be at risk of, significant haemorrhage. Clinicians were blinded to the intervention and the primary outcome was death in hospital within 4 weeks of injury. Secondary outcomes were vascular occlusive events (myocardial infarction, stroke, pulmonary embolism, and deep vein thrombosis), surgical intervention (neurosurgery, thoracic, abdominal, and pelvic surgery), receipt of blood transfusion, and units of blood products transfused. Treatment groups were balanced with respect to all baseline patient characteristics.
All-cause mortality was significantly reduced with tranexamic acid and the risk of death due to bleeding was significantly reduced. Vascular occlusive events (fatal or non-fatal) did not differ significantly between the groups (and were fewer in the tranexamic acid group compared with the placebo group).
All cause mortality in the tranexamic acid group was (1463/10 060) = 14·5% and in the placebo group was (1613/10 067) = 16·0%. So absolute risk reduction is 1.5% and Number Needed to Treat = 67.
The same trials group is investigating the effect of tranexamic acid in post-partum haemorrhage, in a study known as the WOMAN Trial
Take Home Message: the early administration of tranexamic acid to trauma patients with, or at risk of, significant bleeding reduces the risk of death from haemorrhage with no apparent increase in fatal or non- fatal vascular occlusive events. All-cause mortality was significantly reduced with tranexamic acid.
Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): a randomised, placebo-controlled trial
The Lancet, Early Online Publication, 15 June 2010
Thoracic electrical bioimpedance in dyspnoea
Thoracic electrical bioimpedance (TEB) was used in ED patients presenting with dyspnoea to differentiate between cardiac and non-cardiac causes.
The fundamental principle behind TEB is based on Ohm’s law. If a constant electrical current is applied to the thorax, changes in impedance (ΔZ) to flow are equal to changes in voltage drop across the circuit. As a current will always seek the path of lowest resistivity, which in the human body is blood, ΔZ of the thorax will primarily reflect the dynamic changes of blood volume in the thoracic aorta. Changes in thoracic electrical impedance are continuously recorded and processed using a computer algorithm to calculate a number of cardiohaemodynamic parameters such as stroke volume, CO, CI, SVR and systemic vascular resistance index (SVRi).
A cardiac index cut-off of 3.2 l/m/m2 had a 86.7% sensitive (95% CI 59.5% to 98.0%) and 88.9% specific (95% CI 73.9% to 96.8%) for cardiac dyspnoea in the 52 patients studies, of which 15 had cardiac-related dyspnoea.
The study has several limitations including small numbers and using the gold standard of discharge diagnosis.
Thoracic electrical bioimpedance: a tool to determine cardiac versus non-cardiac causes of acute dyspnoea in the emergency department
Emerg Med J. 2010 May;27(5):359-63
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Traumatic Aortic Injury
Two recent papers expand our knowledge of blunt traumatic aortic injury.
UK crash data identified risk factors for low impact blunt traumatic aortic rupture, or ‘LIBTAR’ (crashes at relatively low speed): age >60, lateral impacts and being seated on the side that is struck are predictive of LIBTAR. This study should raise our index of suspicion of aortic injury in low-impact scenarios since low-impact collisions account for two thirds of fatal aortic injuries.
Low-impact scenarios may account for two-thirds of blunt traumatic aortic rupture
Emerg Med J. 2010 May;27(5):341-4
Data from the Victorian State Trauma Registry showed pre-hospital mortality from traumatic thoracic aortic transection was approximately 88.0%, whereas patients who survive to reach hospital have a much lower hospital mortality (33.3%, and once patients who arrived in extremis were removed hospital mortality was reduced to 5.9%). Repair was performed in 46 patients, with 22 receiving initial endovascular repair and 24 receiving initial open repair. Mortality rates following surgery were 9.1% and 16.7%, respectively.
The majority of patients arriving at hospital (57.1%) had an ISS of over 40 highlighting that these patients are unlikely to have only one serious injury and are likely to be more seriously injured than the normal trauma population. An ISS greater than 40 was a main predictor of mortality before repair.
Aortic transection: demographics, treatment and outcomes in Victoria, Australia
Emerg Med J. 2010 May;27(5):368-71
Junior pre-hospital doctors spend a bit longer on scene
More junior pre-hospital doctors took longer on scene than their senior colleagues according to a German study, although patient clinical factors were the main determinant of scene time. The majority of cases were non-trauma presentations
Duration of mission time in prehospital emergency medicine: effects of emergency severity and physicians level of education
Emerg Med J 2010;27:398-403
Terlipressin for refractory cardiac arrest in kids
Okay so it’s a small case series – but the results warrant further investigation: 10-20 mcg/kg terlipressin was given to five infants and children who arrested in the paediatric intensive care unit and who had not responded to several doses of adrenaline (epinephrine)1. Sustained return of spontaneous circulation (ROSC) was achieved in four, and two survived to be discharged home without sequelae and with good neurologic status at 6 and 12 month follow up. Interestingly, the four patients who had ROSC all had septic shock as the cause of their arrest. The two survivors had severe bradycardia and severe bradycarda-asystole as the arrest rhythms, and both received 20 mcg/kg terlipressin.
Terlipressin is a synthetic arginine vasopressin analog with a significantly longer duration of effect, which previously showed positive effects when administered to a small group of children unresponsive to prolonged resuscitative efforts2.
1. Pediatric cardiac arrest refractory to advanced life support: Is there a role for terlipressin?
Pediatr Crit Care Med. 2010 Jan;11(1):139-41
2. Beneficial effects of terlipressin in prolonged pediatric cardiopulmonary resuscitation: A case series.
Crit Care Med. 2007 Apr;35(4):1161-4
Guideline improved pre-hospital RSI in kids
French physicians provide pre-hospital critical care in medical teams of regional SAMU (service d’aide me ́dicale urgente). A national guideline was introduced in France to guide the management of traumatic brain injury (TBI), which included airway management. A study was conducted which examined the practice of paediatric pre-hospital intubation in TBI in comatose children both before and after the introduction of the guideline.
After the guideline there were more pre-hospital intubations, with more standardised approach to rapid sequence induction(RSI). There were fewer complications and a 100% intubation success rate. Despite an increase in portable capnography use, PaCO2 was measured outside the recommended range of 35– 40 mmHg (3.5-4.5 kPa) in 70% of the cases upon arrival.
Emergency tracheal intubation of severely head-injured children: Changing daily practice after implementation of national guidelines
Pediatr Crit Care Med. 2010 May 13. [Epub ahead of print]
Paediatric Retrieval – what's the rush?
The Children’s Acute Transport Service (CATS) in the UK performed 2106 interfacility transports between April 2006 and March 2008. The stabilisation time averaged just over 2 hrs. Stabilisation time was prolonged by the number of major interventions required to stabilise the patient before transfer and differed significantly between various diagnostic groups. The length of time spent by the retrieval team outside the intensive care environment had no independent effect on subsequent patient mortality.
They have shown that stabilisation time can be influenced by a number of patient- and transport team-related factors, and that time spent undertaking intensive care interventions early in the course of patient illness at the referring hospital does not increase patient mortality. In the authors’ words: ‘the “scoop and run” model can be safely abandoned in favor of early goal-directed management during interhospital transport for intensive care.‘
There’s NO rush guys!
Effect of patient- and team-related factors on stabilization time during pediatric intensive care transport
Pediatr Crit Care Med. 2010 May 6
Control oxygenation after resuscitation
How much oxygen should we give patients after successful cardiac arrest resuscitation? Too little oxygen may potentiate anoxic injury. Too much oxygen may increase oxygen free radical production, possibly triggering cellular injury and apoptosis. A multicentre ICU database of over 6300 post-arrest patients was analysed and demonstrated an association between ‘hyperoxia’ and in-hospital mortality.
Adult patients who sustained nontraumatic cardiac arrest and were admitted to the ICU at a participating center between 2001 and 2005 were included. Specifically, inclusion criteria were age older than 17 years, nontraumatic cardiac arrest, cardiopulmonary resuscitation within 24 hours prior to ICU arrival, and arterial blood gas analysis performed within 24 hours following ICU arrival.
The cohort was divided into 3 exposure groups defined a priori based on PaO2 on the first arterial blood gas values obtained in the ICU. Hyperoxia was defined as PaO2 of 300 mm Hg (39.5 kPa) or greater; hypoxia, PaO2 of less than 60 mm Hg (7.9 kPa) (or ratio of PaO2 to fraction of inspired oxygen [FIO2] <300); and normoxia, cases not classified as hyperoxia or hypoxia.
Exposure to hyperoxia was found to be a significant predictor of in-hospital death (OR, 1.8 [95% CI, 1.5-2.2]; this was an independent effect that persisted after adjusting for all other significant risk factors
The authors acknowledge that association does not necessarily imply causation, but add that these data support the hypothesis that high oxygen delivery in the postcardiac arrest setting may have adverse effects.
Association Between Arterial Hyperoxia Following Resuscitation From Cardiac Arrest and In-Hospital Mortality
JAMA. 2010;303(21):2165-2171