A contribution has been made to the literature supporting physician intervention in some pre-hospital trauma patients, in the form of the FIRST study: French Intensive care Recorded in Severe Trauma. 
Not exactly the class 1 evidence we’d (well, I’d) like to see, but a prospective study from France comparing outcomes in patients treated by routine pre-hospital providers with those managed in the field by emergency physicians working for SMUR (Service Mobile d’Urgences et de Réanimation). Primary outcome was 30-day mortality. Only patients admitted to an ICU were included, and researchers were not blinded to which group (SMUR vs nonSMUR) patients belonged. A large group of SMUR patients (2513) was compared with a much smaller (190) nonSMUR group.
Patients were sicker in the SMUR group (lower GCS and SpO2, higher Injury Severity Score, higher frequency of abnormal pupils). Unadjusted mortality was not significantly different but when adjustment for ISS and physiological status was made (I don’t really understand how this was done), SMUR care was significantly associated with a reduced risk of 30-day mortality (OR: 0.55, 95% CI: 0.32-0.94, p = 0.03).
Lots of interesting points in this study, most of which ask more questions that they answer. The French pre-hospital physicians have an aggressive approach to trauma resuscitation, doing rapid sequence intubation in more than a half of their patients and even starting catecholamine infusions as a fluid-sparing strategy in shocked patients. The full text link is worth a read for those interested in this area of medicine.
Medical pre-hospital management reduces mortality in severe blunt trauma: a prospective epidemiological study
Critical Care 2011, 15:R34
Full text as provisional PDF
RV involved in AMI more often than you think
We know that inferior STEMI may be complicated by right ventricular involvement, which is why I whack a V4R lead on all my inferior AMI patients. A recent study using cardiac magnetic resonance imaging showed that RV oedema and regional or global RV dysfunction were common in anterior infarcts too, although the proportion significantly decreased at four month follow up.
RV abnormalities are contiguous to the jeopardized LV myocardium and do not occur exclusively in inferior LV infarcts, but are found in up to 33% of anterior LV infarcts as well. The presence of RV ischemic injury is associated with early RV dysfunction as well as with RV functional recovery at follow-up.
Right Ventricular Ischemic Injury in Patients With Acute ST-Segment Elevation Myocardial Infarction: Characterization With Cardiovascular Magnetic Resonance.
Circulation. 2010 Oct 5;122(14):1405-12
Improved survival with modified CPR
A large randomised controlled trial1 on out-of-hospital cardiac arrest patients compared standard CPR with CPR augmented by two modifications:
- active compression-decompression using a hand-held suction device to compress the chest. The device is attached to the chest of the patient during CPR and the rescuer actively lifts the chest upwards after each compression, which are done at a rate of 80/min
- augmented negative intrathoracic pressure using an impedance threshold device, which is a valve that limits passive air entry into the lungs during chest compressions, thereby reducing intrathoracic pressure and increasing blood flow to vital organs
The primary study endpoint was survival to hospital discharge with favourable neurological function.
Funding issues resulted in premature cessation of the study. 47 (6%) of 813 controls survived to hospital discharge with favourable neurological function compared with 75 (9%) of 840 patients in the intervention group (odds ratio 1·58, 95% CI 1·07–2·36; p=0·019]. 74 (9%) of 840 patients survived to 1 year in the intervention group compared with 48 (6%) of 813 controls (p=0·03), with equivalent cognitive skills, disability ratings, and emotional-psychological statuses in both groups. The overall major adverse event rate did not differ between groups, but more patients had pulmonary oedema in the intervention group (94 [11%] of 840) than did controls (62 [7%] of 813; p=0·015).
An accompanying editorial2 points out that previous studies in animal models of cardiac arrest gave reassuring results for both devices individually and when used together, but results from clinical trials in patients have been mixed for each device when used individually:
- For compression-decompression CPR, a systematic review pooled the existing data for such CPR versus standard CPR in 4162 patients and found no difference in short-term mortality (relative risk 0·98, 95% CI 0·94–1·03) or survival to hospital discharge (0·99, 0·98–1·01). The 2010 CPR guidelines for the USA and Europe do not recommend the use of compression–decompression CPR alone.
- The most current systematic review for the impedance-threshold device showed a significantly improved early survival (relative risk 1·45, 1·16–1·80), and a short-term improved neurological outcome (2·35, 1·30–4·24); however, improved long- term survival did not reach conventional statistical significance (1·48, 0·91–2·41).
The Resuscitation Outcomes Consortium (ROC) PRIMED study3 showed no survival benefit in 8718 patients randomised to standard CPR with an active or sham impedance-threshold device (the Consortium includes the same investigators as the Lancet paper). This was published as an abstract in Circulation recently.
The editorialist has reservations regarding a change in clinical practice resulting from this new study, partly because the trial was stopped prematurely and enrolment of a larger cohort could have changed the findings, and partly because the open use of both devices might have unintentionally introduced bias into the study. Further validation is recommended.
1. Standard cardiopulmonary resuscitation versus active compression-decompression cardiopulmonary resuscitation with augmentation of negative intrathoracic pressure for out-of-hospital cardiac arrest: a randomised trial
Lancet 2011;377:301-11
2. Augmented CPR: rescue after the ResQ trial
Lancet. 2011 Jan 22;377:276-7
3. The Resuscitation Outcomes Consortium ROC) PRIMED Impedance Threshold Device (ITD) Cardiac Arrest Trial: A Prospective, Randomized, Double-Blind, Controlled Clinical Trial
Circulation 2010; 122: 2215–26 (abstr)
Open thoracostomy
Not a new paper to cite here, just a collection of resources that refer to open thoracostomy in trauma.
A longstanding practice by some European and Australasian HEMS physicians, open thoracostomy is essentially a chest tube procedure without the actual intercostal catheter: the surgical incision is made, blunt dissection is performed, and the pleura penetrated. The wound is then left open.
This is a rapid way of decompressing a tension pneumothorax in a critically injured trauma patient who is intubated. The positive pressure ventilation prevents the thoracostomy wound from acting as an open, ‘sucking’, chest wound.
In many pre-hospital services this is the preferred approach to pleural decompression in an intubated patient, and also forms part of the approach to resuscitation in traumatic cardiac arrest.
Some principles to consider are:
- A tube and drainage system are not necessary for the drainage of air, but should be used if there is signficant haemothorax
- The tissues may re-appose during transport so physiological deterioration should prompt a re-fingering of the thoracostomy to re-establish the drainage tract and allow air to escape
- Standard intravenous cannula devices may be shorter than the distance from chest wall to pleural space in many adults, adding to the inadequacy of needle decompression
- Signs of tension pneumothorax are rarely if ever as obvious as the textbooks suggest – unexplained shock or hypoxaemia in a patient with actual or probably thoracic trauma should prompt consideration of pleural decompression even in the absence of obvious clinical signs of pneumothorax – subtle evidence only may exist, such as palpable subcutaneous emphysema
- This should only be done in intubated patients undergoing positive pressure ventilation!
This video shows the procedure, done by a relative beginner; a slightly larger incision with more assertive dissection would make it faster and more effective
Not yet heard Scott Weingart’s excellent podcast on traumatic arrest, which includes open, or ‘finger’, thoracostomy? You can find it here
Thoracostomy references
Simple Thoracostomy Avoids Chest Drain Insertion in Prehospital Trauma
J Trauma 1996 39(2):373-374
Simple thoracostomy in prehospital trauma management is safe and effective: a 2-year experience by helicopter emergency medical crews
European Journal of Emergency Medicine 2006, 13:276–280
Prehospital thoracostomy
European Journal of Emergency Medicine 2008, 15:283–285
Chest decompression during the resuscitation of patients in prehospital traumatic cardiac arrest
Emerg. Med. J. 2009;26;738-740
Life-saving or life-threatening? Prehospital thoracostomy for thoracic trauma
Emerg Med J 2007;24:305–306
Pre-Hospital and In-Hospital Thoracostomy: Indications and Complications
Ann R Coll Surg Engl. 2008 January; 90(1): 54–57
Needle decompression is inadequate:
Needle Thoracostomy in the Treatment of a Tension Pneumothorax in Trauma Patients: What Size Needle?
J Trauma. 2008;64:111–114
Pre-hospital management of patients with severe thoracic injury
Injury 1995 26(9):581-5
Sux vs Roc in ED RSI
Suxamethonium and rocuronium were compared in a database of prospectively recorded cases of RSI in the emergency department.
A total of 327 RSI were included in the final analyses. All patients received etomidate as the induction sedative and were successfully intubated. Of these, 113 and 214 intubations were performed using succinylcholine and rocuronium, respectively.
- The rate of first-attempt intubation success was similar between the succinylcholine and rocuronium groups (72.6% vs. 72.9%, p = 0.95).
- Median doses used for succinylcholine and rocuronium were 1.65 mg/kg (interquartile range [IQR] = 1.26–1.95 mg/kg) and 1.19 mg/kg (IQR = 1–1.45 mg/kg), respectively.
- The median dose of etomidate was 0.25 mg/kg in both groups.
In this study succinylcholine and rocuronium were equivalent with regard to first-attempt intubation success in the ED. This finding is consistent with previous investigations that used doses between 0.9 and 1.2 mg/kg and found similar intubating conditions to succinylcholine at these higher doses; subgroup analyses of studies using a lower rocuronium dose of 0.6 to 0.7 mg/kg had a relative risk favoring succinylcholine for excellent intubating conditions.
The low (in my view) rate of first-attempt intubation success in both groups was (72.6% vs. 72.9%), does make one wonder whether the intubating clinicians optimised their strategy for first-pass success.
Comparison of Succinylcholine and Rocuronium for First-attempt Intubation Success in the Emergency Department
Acad Emerg Med. 2011;18:11-14
Algorithm for Body Packers
‘Mules’ or body packers are people who transport illegal drugs by packet ingestion into the gastrointestinal tract. A large study of body packers apprehended by United State Customs officials at JFK International Airport, New York describes experience with body packers and an algorithm for conservative and surgical management.
Of 56 patients requiring admission out of a total of 1250 subjects confirmed to be body packers, 25 patients (45%) required surgical intervention, whereas 31 patients (55%) were successfully managed conservatively.
Diagnosis:
- Plain abdominal x-ray was diagnostic in 49 patients (88% of all hospitalised patients).
- Non-contrast CT of the abdomen and pelvis is required if AXR is negative
- Forty-eight per cent of body packers had positive urine toxicology for illicit substances.
Management:
- Indications for intervention included:
- bowel obstruction
- packet rupture/toxicity
- delayed progression of packet transit on conservative management.
- Patients with packets found predominantly in the proximal gastrointestinal tract failed conservative management more frequently than those with packets found in the distal gastrointestinal tract.
Multiple intraoperative manoeuvres were used to remove the foreign bodies:
- gastrotomy
- enterotomy
- colotomy.
Wound infection was the most common complication and is associated with distal enterotomy and colotomy.
The authors recommend a confirmatory radiological study to demonstrate complete clearance of packets
Establishment of a definitive protocol for the diagnosis and management of body packers (drug mules).
Emerg Med J 2011;28:98-10
Hole in the head? Don't waste the window!
Zampieri and colleagues from Brazil report the use of brain ultrasound in two ICU patients who had had hemicraniectomies.
One of the patients had a subarachnoid haemorrhage with hydrocephalus and an infarct due to vasospasm requiring hemicraniectomy, who subsequently deteriorated with decreasing ventricular catheter drainage, raising suspicion of acute hydrocephalus. Brain ultrasonography confirmed moderate hydrocephalus which was seen to improve after catheter desobstruction.
The authors note: ‘standard ultrasonography can be performed through a hemicraniectomy field and may be helpful in a small group of patients. Since decompressive hemicraniectomy is increasingly being used in critical care medicine, bedside evaluation of the brain using the hemicraniectomy as an insonation window could be useful as a noninvasive triage tool and reduce the need for patient transport to the imaging center.’
Use of ultrasonography in hemicraniectomized patients: a report of two cases
Intensive Care Med. 2010 Dec;36(12):2161-2
Not got a hole in the skull? Could try a bony ultrasound window – compare the clear scans above with this scan of an extradural haematoma
Most detailed image of night sky unveiled
From New Scientist
18:30 11 January 2011 by David Shiga, Seattle
It would take 500,000 high-definition TVs to view it in its full glory. Astronomers have released the largest digital image of the night sky ever made, to be mined for future discoveries.
It is actually a collection of millions of images taken since 1998 with a 2.5-metre telescope at Apache Point Observatory in New Mexico. The project, called the Sloan Digital Sky Survey, is now in its third phase, called SDSS-III.
Altogether, the images in the newly released collection contain more than a trillion pixels of data, covering a third of the sky in great detail.
“This is one of the biggest bounties in the history of science,” says SDSS team member Mike Blanton of New York University in New York City. “This data will be a legacy for the ages.”
via Most detailed image of night sky unveiled – space – 11 January 2011 – New Scientist – READ MORE…
Hypothermia and hypokalaemia
We all like to treat selected post cardiac arrest patients with hypothermia now, but isn’t hypothermia associated with a drop in potassium, which of course can precipitate pesky ventricular dysrhythmias in patients who would really rather not arrest again. Maybe the hypothermia itself is protective against the dysrhythmias?
A study from the Mayo Clinic updates our knowledge of this area:
METHODS: We retrospectively analyzed potassium variability with Therapeutic Hypothermia (TH) and performed correlative analysis of QT intervals and the incidence of ventricular arrhythmia.
RESULTS: We enrolled 94 sequential patients with OHCA, and serum potassium was followed intensively. The average initial potassium value was 3.9±0.7 mmol/l and decreased to a nadir of 3.2±0.7 mmol/l at 10 h after initiation of cooling (p<0.001). Eleven patients developed sustained polymorphic ventricular tachycardia (PVT) with eight of these occurring during the cooling phase. The corrected QT interval prolonged in relation to the development of hypothermia (p<0.001). Hypokalemia was significantly associated with the development of PVT (p=0.002), with this arrhythmia being most likely to develop in patients with serum potassium values of less than 2.5 mmol/l (p=0.002). Rebound hyperkalemia did not reach concerning levels (maximum 4.26±0.8 mmol/l at 40 h) and was not associated with the occurrence of ventricular arrhythmia. Furthermore, repletion of serum potassium did not correlate with the development of ventricular arrhythmia.
CONCLUSIONS: Therapeutic hypothermia is associated with a significant decline in serum potassium during cooling. Hypothermic core temperatures do not appear to protect against ventricular arrhythmia in the context of severe hypokalemia and cautious supplementation to maintain potassium at 3.0 mmol/l appears to be both safe and effective.
Hypokalemia during the cooling phase of therapeutic hypothermia and its impact on arrhythmogenesis
Resuscitation. 2010 Dec;81(12):1632-6
Pre-hospital iv and increased mortality
The US media seem to be making a big thing of a recent article published ahead of print which demonstrates an association between increased mortality from trauma and the insertion of an intravenous line with or without the administration of fluid.
This was a retrospective cohort study of over 770 000 patients from the National Trauma Data Bank. Approximately half (49.3%) received ‘prehospital IV’, which could mean fluids, or could just mean insertion of an intravenous cannula: ‘we could not definitively differentiate IV fluid administration versus IV catheter placement alone‘.
Unadjusted mortality was significantly higher in patients in the prehospital IV group, although the abstract inaccurately reports this to be ‘in patients receiving prehospital IV fluids‘ (4.8% vs. 4.5%, P < 0.001).
Multivariable logistic regression was used to examine the relationship between prehospital IV and mortality in the 311,071 patients with complete data. After adjustment, prehospital IV patients had significantly higher mortality than those without a prehospital IV. The odds ratio of death associated with prehospital IV placement was 1.11 (95% CI 1.06–1.17). When Dead-On-Arival patients were excluded from the group as a whole, the association persisted (OR 1.17, 95% CI 1.11–1.23).
On subgroup analyses, the association between IV placement and excess mortality was maintained in nearly all patient subsets; the effect was more exaggerated in penetrating trauma victims.
Media speculation as to the reason for this association abounds, like USA Today‘s ‘those who are given pre-hospital IV fluids are actually 11% more likely to die than those who aren’t, not only because of transport delays but also in part because of the increased risk for bleeding that can accompany a fluid-induced increase in blood pressure‘. However the study did not record any pre-hospital times and could not tell which patients received fluid, let alone what the effect of fluid on blood pressure was.
The authors are open about this and other limitations: ‘The NTDB did not report prehospital transport times or differentiate urban versus rural care. Thus, we could not examine whether excess mortality in patients treated with IVs was directly associated with delays in transport to definitive care. We were also not able to control for transport time within the multiple regression model or perform a stratified analysis by urban versus rural patients. Perhaps this analysis would have identified a subset of patients who may benefit from IV placement‘.
No doubt this will be added to the pile of mainly hypothesis-generating literature quoted by the scoop-and-run brigade whose black-and-white worldview includes paramedics who want to delay proper treatment and a homogeneous trauma population whose lives can only be saved by a trauma surgeon in a hospital. Those who have evolved colour vision find this an interesting, but hardly practice-changing study; caution regarding injudicious fluid administration has been the game plan for many civilian and military pre-hospital providers since early last decade, and it is clear that different patients with different injury patterns, different degrees of physiological derangement, and different distances from the right hospital will continue to have different clinical needs specific to their presentation, some of which are likely to be of benefit if provided in the field, through an intravenous line.
Prehospital Intravenous Fluid Administration is Associated With Higher Mortality in Trauma Patients: A National Trauma Data Bank Analysis
Ann Surg. 2010 Dec 20. [Epub ahead of print]