Data on patients with moderate to severe traumatic brain injury from the San Diego Trauma Registry were analysed using modified TRISS methodology to determine predicted survival, from which an observed-predicted survival differential (OPSD) was calculated. The mean OPSD was calculated as the primary outcome for the following comparisons: intubated versus nonintubated, air versus ground transport, eucapnia (PCO2 30–50 mm Hg) versus noneucapnia, and hypoxemia (PO<90 mm Hg) versus nonhypoxemia. Of note in this region is that ground EMS staff intubate without drugs, whereas air medical services use rapid sequence intubation with suxamethonium plus either etomidate or midazolam.
The rationale behind this methodology was to eliminate the possible selection bias present in previous studies linking pre-hospital intubation with mortality (sicker patients are able to be intubated without drugs).
A total of 9,018 TBI patients had complete data to allow calculation of probability of survival using TRISS. A total of 16.7% of patients were intubated in the field; 49.6% of these were transported by air medical providers. Patients undergoing prehospital intubation, transported by ground, with arrival eucapnia, and without arrival hypoxemia had higher mean OPSD values.
Intubated patients were more likely to be “unexpected survivors” and live to hospital discharge despite low predicted survival values; patients transported by air medical personnel had higher OPSD values and had a higher proportion of unexpected survivors. No statistically significant differences were observed between air- and ground-transported patients with regard to arrival PCO2 values arrival PO2 values.
Prehospital Airway and Ventilation Management: A Trauma Score and Injury Severity Score-Based Analysis
J Trauma. 2010 Aug;69(2):294-301
Neuro-folks at LAC+USC Medical Centre describe outcomes for patients with traumatic brain injury without space-occupying haemorrhage who underwent decompressive craniectomy for intracranial hypertension refractory to maximal medical therapy. Of 43 included patients, 25.6% died (11 of 43), and 32.5% (14 of 43) remained in vegetative state or were severely disabled. Favourable outcome (Glasgow Outcome Scale 4 and 5) was observed in 41.9% (18 of 43). More evidence will result from two ongoing randomised multicentre trials: the European RescueICP study and the Australian DECRA trial.
Decompressive craniectomy: Surgical control of traumatic intracranial hypertension may improve outcome
Injury. 2010 Jul;41(7):934-8
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]
A literature review addresses the myth that ketamine is contraindicated in head injured patients. They summarise articles from the 1970’s which identified an association between ketamine and increased ICP in patients with abnormal cerebrospinal fluid pathways (such as those caused by aqueductal stenosis, obstructive hydrocephalus and other mass effects). In more recent studies no statistically significant increase in ICP was observed following the administration of ketamine in patients with head injury; some of the studies showed a net increase in CPP following ketamine administration. They list ketamine’s stable haemodynamic profile and potential neuroprotective effects as further rationale for its use.
The authors boldly summarise:
‘Based on its pharmacological properties, ketamine appears to be the perfect agent for the induction of head-injured patients for intubation.’
Myth: ketamine should not be used as an induction agent for intubation in patients with head injury
CJEM. 2010 Mar;12(2):154-7
A retrospective study from Italy compared outcomes of head injured patients cared for by a ground ambulance service (GROUND) with those managed by a HEMS team that included an experienced pre-hospital anaesthetist. Interestingly 73% of the ground group were also attended by a physician, but one ‘with only basic life-support capabilities and no formal training in airways management’. Despite these limited skills a results table shows that 36% of the GROUND group were intubated on scene (compared with 92% of the HEMS group), although without the use of neuromuscular blockers.
The HEMS group consisted of 89 patients and the GROUND group of 105 patients. There were no statistical differences in age, ISS, aISShead, or GCS, although arterial hypotension at arrival at the ER was present in 18% of HEMS patients and in 36% of GROUND patients (P < 0.001).
The overall mortality rate was lower in the HEMS than in the GROUND group (21 vs. 25% , P < 0.05). The survival with or without only minor neurological disabilities was higher in the HEMS than in the GROUND group (54 vs. 44% respectively, P < 0.05); among the survivors, the rate of severe neurological disabilities was lower in the HEMS than in the GROUND group (25 vs. 31%, P < 0.05). The out-of-hospital phase duration was longer in the HEMS group but this group had a faster time to definitive care (neurosurgery or neurocritical care).
Influence of prehospital treatment on the outcome of patients with severe blunt traumatic brain injury: a single-centre study
Eur J Emerg Med. 2009 Dec;16(6):312-7
The 2009 SIGN Guidelines on Early Management of Patients with Head Injury contain extensive additional resources, such as documentation proformas for adults and children, discharge instructions, and guidance on returning to sport after head injury.
Prehospital management of severe traumatic brain injury
A review of current practice and evidence base of this important topic can be found at
BMJ. 2009 May 19;338:b1683
Full text http://www.bmj.com/cgi/content/full/338/may19_1/b1683
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
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
Further evidence from the UK shows that patients with acute traumatic brain injury suffer delays in the neurosurgical evacuation of intracranial haematomas which are increased from an average of 3.7 hours to 5.4 hours if they have to undergo interhospital transfer. Coordinated regional trauma systems please!
A prospective study of the time to evacuate acute subdural and extradural haematomas.
Anaesthesia. 2009 Mar;64(3):277-81