Body temperature does not necessarily reflect brain temperature
Low brain temperature was independently associated with a worse outcome in a recent study
Brain temperature within the range of 36.5°C to 38°C was associated with a lower probability of death in this study
There are no randomised studies on which to base the practice of aggressive cooling of febrile patients with traumatic brain injury
There are few prospective studies reporting the effect of spontaneous temperature changes on outcome after severe traumatic brain injury (TBI). Where studies have been conducted, results are based on systemic rather than brain temperature per se. However, body temperature is not a reliable surrogate for brain temperature. Consequently, the effect of brain temperature changes on outcome in the acute phase after TBI is not clear. Continuous intraparenchymal brain temperature was measured in consecutive admissions of severe TBI patients during the course of the first 5 days of admission to the intensive care unit (ICU). Patients received minimal temperature altering therapy during their ICU stay. Logistic regression was used to explore the relationship between the initial, the 24-h mean, and the 48-h mean brain temperature with outcome for mortality at 30 days and outcome at 3 months. Multifactorial analysis was performed to account for potential confounders. At the 24-h time point, brain temperature within the range of 36.5°C to 38°C was associated with a lower probability of death (10-20%). Brain temperature outside of this range was associated with a higher probability of death and poor 3-month neurological outcome. After adjusting for other predictors of outcome, low brain temperature was independently associated with a worse outcome. Lower brain temperatures (below 37°C) are independently associated with a higher mortality rate after severe TBI. The results suggest that, contrary to current opinion, temperatures within the normal to moderate fever range during the acute post-TBI period do not impose an additional risk for a poor outcome after severe TBI.
The effect of spontaneous alterations in brain temperature on outcome: a prospective observational cohort study in patients with severe traumatic brain injury.
J Neurotrauma. 2010 Dec;27(12):2157-64
An ultrasound study of paediatric airways showed sonographic measurement to be a better predictor of tracheal tube size (using a formula – derived and then validated – to estimate external tube diameter) than traditional formulae for selecting the internal tube diameter based on age. Since the measurements, taken at the lower edge of the cricoid cartilage, were made after patients were paralyzed, and were performed without ventilation or positive end-expiratory pressure to minimize fluctuation in tracheal diameter, taking about 30 seconds, this is not something I anticipate applying in critical care practice. However, the paper does provide a good opportunity to revise some of the existing formulae. They used:
(1) The Cole formula for uncuffed tubes: ID (intenal diameter) in mm= (age in years)/4 + 4
(2) The Motoyama formula for cuffed ETTs in children aged 2 yr or older: ID in mm = (age in years)/4 + 3.5
(3) The Khine formula for cuffed ETTs in children younger than 2 yr: ID in mm = (age in years)/4 + 3.0
The formula established in the study was:
cuffed ETT outer diameter (OD) = 0.46 x (subglottic diameter) + 1.56
uncuffed ETT OD = 0.55 x (subglottic diameter) + 1.16
Age in months also correlated with optimal ETT size in mm, although the correlation was weaker than for subglottic diameter:
cuffed ETT OD = 0.027 x (age) + 5.2
uncuffed ETT OD = 0.030 x (age) + 5.4
BACKGROUND: Formulas based on age and height often fail to reliably predict the proper endotracheal tube (ETT) size in pediatric patients. We, thus, tested the hypothesis that subglottic diameter, as determined by ultrasonography, better predicts optimal ETT size than existing methods. METHODS: A total of 192 patients, aged 1 month to 6 yr, who were scheduled for surgery and undergoing general anesthesia were enrolled and divided into development and validation phases. In the development group, the optimal ETT size was selected according to standard age-based formulas for cuffed and uncuffed tubes. Tubes were replaced as necessary until a good clinical fit was obtained. Via ultrasonography, the subglottic upper airway diameter was determined before tracheal intubation. We constructed a regression equation between the subglottic upper airway diameter and the outer diameter of the ETT finally selected. In the validation group, ETT size was selected after ultrasonography using this regression equation. The primary outcome was the fraction of initial cuffed and uncuffed tube sizes, as selected through the regression formula, that proved clinically optimal. RESULTS: Subglottic upper airway diameter was highly correlated with outer ETT diameter deemed optimal on clinical grounds. The rate of agreement between the predicted ETT size based on ultrasonic measurement and the final ETT size selected clinically was 98% for cuffed ETTs and 96% for uncuffed ETTs. CONCLUSIONS: Measuring subglottic airway diameter with ultrasonography facilitates the selection of appropriately sized ETTs in pediatric patients. This selection method better predicted optimal outer ETT diameter than standard age- and height-based formulas.
Elective surgery patients were anaesthetised with propofol with or without fentanyl and had an oropharyngeal airway placed. They were ventilated with pressure control ventilation via facemask held with a single handed traditional ‘EC clamp’ grip and with a two-handed jaw thrust, and compared. The order in which these two techniques were trialled was randomised. All breaths were delivered with a peak pressure of 15 cm H2O, an inspiratory-to-expiratory ratio of 1:1, at a frequency of 15 breaths per minute. Ventilation was more effective with the two handed technique. Using a self-inflating bag for resuscitation, this would translate to a two-person technique. Of note in methodology however was use of a ‘standard pillow’ and some emphasis on head extension. Perhaps ventilation would have been more effective with either technique if they had applied the golden rule of ear-to-sternal-notch positioning: a must for effective mask ventilation and successful laryngoscopy.
BACKGROUND: Mask ventilation is considered a “basic” skill for airway management. A one-handed “EC-clamp” technique is most often used after induction of anesthesia with a two-handed jaw-thrust technique reserved for difficult cases. Our aim was to directly compare both techniques with the primary outcome of air exchange in the lungs. METHODS: Forty-two elective surgical patients were mask-ventilated after induction of anesthesia by using a one-handed “EC-clamp” technique and a two-handed jaw-thrust technique during pressure-control ventilation in randomized, crossover fashion. When unresponsive to a jaw thrust, expired tidal volumes were recorded from the expiratory limb of the anesthesia machine each for five consecutive breaths. Inadequate mask ventilation and dead-space ventilation were defined as an average tidal volume less than 4 ml/kg predicted body weight or less than 150 ml/breath, respectively. Differences in minute ventilation and tidal volume between techniques were assessed with the use of a mixed-effects model. RESULTS: Patients were (mean ± SD) 56 ± 18 yr old with a body mass index of 30 ± 7.1 kg/m. Minute ventilation was 6.32 ± 3.24 l/min with one hand and 7.95 ± 2.70 l/min with two hands. The tidal volume was 6.80 ± 3.10 ml/kg predicted body weight with one hand and 8.60 ± 2.31 ml/kg predicted body weight with two hands. Improvement with two hands was independent of the order used. Inadequate or dead-space ventilation occurred more frequently during use of the one-handed compared with the two-handed technique (14 vs. 5%; P = 0.013). CONCLUSION: A two-handed jaw-thrust mask technique improves upper airway patency as measured by greater tidal volumes during pressure-controlled ventilation than a one-handed “EC-clamp” technique in the unconscious apneic person.
A first report of thyroid cartilage fracture resulting from laryngoscopy and intubation has been published. An elective surgery patient underwent paralysis with 60 mg rocuronium after which ‘laryngoscopy and intubation attempts with a Macintosh 3 blade, Miller 2 blade, stylet, and vigorous external laryngeal manipulation yielded only Cormack Lehane grade 3 views of the larynx‘. Intubation was eventually achieved with a Glidescope, but it was noted that ‘external laryngeal manipulation was applied as forcefully as the assistant could perform the maneuver‘.
The author suggests the fracture could either have resulted from the external laryngeal manipulation during laryngoscopy or from the rigid curved stylet used with the Glidescope. Whichever it was, their take home advice is sound:
Even during difficult laryngoscopies, gentle manipulations are best
Doctors from Britain’s most established major trauma centre – the Royal London Hospital – have produced mortality data over a four year period of trauma team activations.
Introduction Trauma data collection by UK hospitals is non-mandatory and data regarding trauma mortality are deficient. Our aim was to provide a contemporary description of mortality in a maturing trauma-receiving hospital serving an inner-city population. Methods A prospectively maintained registry was analysed for demographics; injury mechanism; and time, location and cause of death in trauma patients admitted via the Emergency Department between 2004 and 2008. Results 4986 trauma team activations yielded 4243 complete cases. The number of patients rose from 784 in 2004-2005 to 1400 in 2007/8. 302 (7%) of these died. All-cause mortality fell from 8.8% to 5.8% (p=0.0075). Blunt trauma (predominantly falls from height and road traffic collisions) accounted for 79% of admissions but 87% of mortality. Penetrating trauma accounted for 21% of admissions and 13% of mortality. Most penetrating injury deaths were from stabbing injury (31/40) as opposed to gunshot wounds (8/40). The biggest cause of death was central nervous system injury (47.7%) followed by haemorrhage (26.2%). Penetrating injury death was associated with marked shock and acidosis compared to blunt mechanisms-mean (SD) admission systolic blood pressure 25.4 (45.7) versus 105.5 (60.5) mm Hg; mean (SD) base excess -21.84 (7.2) versus 9.71 (8.45) mmol, respectively. No classical trimodal distribution of death was observed. Conclusion Despite current focus on death from knife and gun crime, the vast majority of trauma mortality arises from blunt aetiology. Maturation of our systems of care has been associated with a drop in mortality as institutional trauma volumes increase and clinical infrastructure develops.
Recent recommendations were made regarding trauma care in the UK by the National Confidential Enquiry into Patient Outcome and Death (NCEPOD).
British military physicians at the UK military field hospital, Camp Bastion, Helmand Province, Afghanistan, evaluated their trauma cases against these standards. It is apparent that the trauma care provided to some people in Afghanistan outclasses that delivered within much of the UK.
Background The National Confidential Enquiry into Patient Outcome and Death (NCEPOD) report on trauma management, published in 2007, defined standards for United Kingdom (UK) hospitals dealing with trauma. This study compared the NCEPOD standards with the performance of a UK military field hospital in Afghanistan. Setting UK military field hospital, Camp Bastion, Helmand Province, Afghanistan. Materials and methods Data were collected prospectively for all patients fulfilling the trauma team activation criteria during the 3 months of Operation Herrick IXa (from mid October 2008 to mid January 2009) and combined with a retrospective review of prehospital documentation, trauma resuscitation notes, operations notes and transfer notes for these patients. Results During the study period, there were 226 trauma team activations. Of those patients brought to the medical facility at Camp Bastion by UK assets, 93.7% were accompanied by a doctor with advanced airway skills, although only 6.2% of the patients required such an intervention. Consultants in emergency medicine and anaesthesia were present in 100% of cases and were directly involved (in either leading the team or performing airway management) in 63.5% and 77.6% of cases respectively. Of those patients requiring operative intervention, 98.1% had this performed by a consultant surgeon. Of those patients requiring CT, 93.6% of cases had this performed within 1 h of arrival. Conclusions Trauma patients presenting to the medical facility at Camp Bastion during Operation Herrick IXa, irrespective of their nationality or background, received a high standard of medical care when compared with the NCEPOD standards
National Confidential Enquiry into Patient Outcome and Death recommendations Pre-hospital care
All agencies involved in trauma management, including emergency medical services, should be integrated into the clinical governance programmes of a regional trauma service. Airway management in trauma patients is often challenging, and the pre-hospital response for these patients should include someone with the skill to secure the airway, (including the use of rapid sequence intubation), and maintain adequate ventilation. Hospital reception
A trauma team should be available 24 h a day, 7 days a week. This is an essential part of an organised trauma response system. A consultant must be the team leader for the management of the severely injured patient. Airway and breathing
The current structure of prehospital management is insufficient. There is a high incidence of failed intubation and a high incidence of patients arriving at hospital with a partially or completely obstructed airway. Change is urgently required to provide a system that reliably provides a clear airway with good oxygenation and control of ventilation. This may be through the provision of personnel with the ability to provide anaesthesia and intubation in the prehospital phase or through the use of alternative airway devices. Circulation
Trauma laparotomy is extremely challenging and requires consultant presence within the operating theatre. If CT is to be performed, all necessary images should be obtained at the same time, and routine use of head-to-toe scanning is recommended in the adult trauma patient if no indication for immediate intervention exists. Head injuries
Patients with severe head injury should have a CT of the head performed as soon as possible after admission and within 1 hour of arrival at the hospital. All patients with severe head injury should be transferred to a neurosurgical critical care centre irrespective of the requirement for surgical intervention. Transfers
There should be standardised transfer documentation of patient details, injuries, results of investigations and management, with records kept at the dispatching and receiving hospitals. A comparison of civilian (National Confidential Enquiry into Patient Outcome and Death) trauma standards with current practice in a deployed field hospital in Afghanistan. Emerg Med J 2011;28:310-312
I published a case report in the EMJ highlighting the use of intranasal ketamine in a pre-hospital paediatric burns case.
The lad had nasty scalds but did not need iv fluids and had no other indications for an iv line. The vigorous first aid had rendered him cold and veinless and an intraosseous would have been overkill. Ketamine was perfect for the job and Ambulance Service New South Wales paramedics carry a mucosal atomisation device (MAD) for the administration of i.n. fentanyl. I used the MAD to adminster 0.5 mg/kg ketamine, but there is a dead space in the device (0.1 ml) that probably resulted in actual delivery of 0.25mg/kg. This gave great analgesia and compliance enabling us to painlessly apply polyethylene film to the burns.
I received the following email from TIm Wolfe, the inventor of the MAD nasal (reproduced with permission):
Nice contribution to the literature. There is a lot of interest in IN ketamine in these lower doses to treat pain but not cause sedation. You eluded to the military interest and the hospice interest. I think your insights for EMS are also cutting edge – hopefully this will lead others to design a larger trial.
Tim Wolfe, MD
Background Every day throughout the UK, ambulance services seek medical assistance in providing critically ill or injured patients with pre-hospital care. Objective To identify the current availability and utilisation of physician-based pre-hospital critical care capability across England, Wales and Northern Ireland. Design A postal and telephone survey was undertaken between April and December 2009 of all 13 regional NHS ambulance services, 17 air ambulance charities, 34 organisations affiliated to the British Association for Immediate Care and 215 type 1 emergency departments in England, Wales and Northern Ireland. The survey focused on the availability and use of physician-based pre-hospital critical care support. Results The response rate was 100%. Although nine NHS ambulance services recorded physician attendance at 6155 incidents, few could quantify doctor availability and utilisation. All but one of the British Association for Immediate Care organisations deployed ‘only when available’ and only 45% of active doctors could provide critical care support. Eleven air ambulance services (65%) operated with a doctor but only 5 (29%) operated 7 days a week. Fifty-nine EDs (27%) had a pre-hospital team but only 5 (2%) had 24 h deployable critical care capability and none were used regularly. Conclusion There is wide geographical and diurnal variability in availability and utilisation of physician-based pre-hospital critical care support. Only London ambulance service has access to NHS-commissioned 24 h physician-based pre-hospital critical care support. Throughout the rest of the UK, extensive use is made of volunteer doctors and charity sector providers of varying availability and capability.
Loss of consciousness can occur when a patient is suspended in a harness – ‘suspension syncope’, probably due to factors that include venous pooling in the lower limbs. An evidence based review of this entity was carried out:
The possibility of a fall into rope protection and subsequent suspension exists in some industrial situations. The action to take for the first aid management of rescued victims has not been clear, with some authors advising against standard first aid practices. To clarify the medical evidence relating to harness suspension the UK Health and Safety Executive commissioned an evidence-based review and guideline. Four key questions were posed relating to the incidence, circumstances, recognition and first aid management of the medical effects of harness suspension. A comprehensive literature search returned 60 potential papers with 29 papers being reviewed. The Scottish Intercollegiate Guideline Network (SIGN) methodology was used to critically review the selected papers and develop a guideline. A stakeholders’ workshop was held to review the evidence and draft recommendations. Nine papers formed the basis of the guideline recommendations. No data on the incidence of harness suspension syncope were found. Presyncopal symptoms or syncope are thought to occur with motionless suspension as a consequence of orthostasis leading to hypotension. There was no evidence of any other pathology, despite this being hypothesised by others. No evidence was found that showed the efficacy or safety of positioning a victim in a semirecumbent position. In any case of harness suspension, the standard UK first aid guidance for recovery of a semiconscious or unconscious person in a horizontal position should be followed. Other recommendations included areas for further research and proposals for standard data collection on falls into rope protection.
A review of extracorporeal life support for out-of-hospital cardiac arrest was undertaken, looking specifically at studies published in the Japanese literature. The abstract is shown below. Based on these findings, inclusion criteria for a multicentre, prospective non-randomised cohort study were established. The ‘SAVE-J: Study of advanced life support for ventricular fibrillation with extracorporeal circulation in Japan’ was launched and has been ongoing since October 2008 to compare the proportion of patients with a favourable neurological outcome by intention-to-treat in an ECPR group with a non-ECPR group. Inclusion criteria for this new study are:
shockable rhythm on the initial ECG
cardiac arrest on arrival at hospital regardless of the presence of recovery of spontaneous circulation before arrival
arrival at hospital within 45 min of the call for an ambulance or cardiac arrest;
cardiac arrest remaining for more than 15 min after arrival at hospital.
AIM: Although favourable outcomes in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest have been frequently reported in Japanese journals since the late 1980s, there has been no meta-analysis of ECPR in Japan. This study reviewed and analysed all previous studies in Japan to clarify the survival rate of patients receiving ECPR. MATERIAL AND METHODS: Case reports, case series and abstracts of scientific meetings of ECPR for out-of-hospital cardiac arrest written in Japanese between 1983 and 2008 were collected. The characteristics and outcomes of patients were investigated, and the influence of publication bias of the case-series studies was examined by the funnel-plot method. RESULTS: There were 1282 out-of-hospital cardiac arrest patients, who received ECPR in 105 reports during the period. The survival rate at discharge given for 516 cases was 26.7±1.4%. The funnel plot presented the relationship between the number of cases of each report and the survival rate at discharge as the reverse-funnel type that centred on the average survival rate. In-depth review of 139 cases found that the rates of good recovery, mild disability, severe disability, vegetative state, death at hospital discharge and non-recorded in all cases were 48.2%, 2.9%, 2.2%, 2.9%, 37.4% and 6.4%, respectively. CONCLUSIONS: Based on the results of previous reports with low publication bias in Japan, ECPR appears to provide a higher survival rate with excellent neurological outcome in patients with out-of-hospital cardiac arrest.