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
Category Archives: PHARM
Prehospital and Retrieval Medicine
Optimum depth of neonatal chest compressions
A retrospective study of infant chest CT scans using mathematical modelling and a number of assumptions suggests that neonatal CPR according to AAP/AHA guidelines of compressing to one third anteroposterior chest wall diameter should provide a superior ejection fraction to 1/4 depth and should generate less risk for over-compression than 1/2 AP compression depth.
Evaluation of the Neonatal Resuscitation Program’s recommended chest compression depth using computerized tomography imaging
Resuscitation. 2010 May;81(5):544-8
Compare their conclusions with those of the authors of this case series of arterial-line monitored cardiac arrests in infants with a median age of one month
Hospital bypass for cardiac arrest?
A Japanese study of over 10,000 patients demonstrated improved neurological outcome in out-of-hospital cardiac arrest patients who were taken to hospitals designated as ‘critical care medical centres’, where neurologically favorable 1-month survival was greater [6.7% versus 2.8%, P < 0.001] despite a slightly longer call-hospital arrival interval [30.6 min vs 27.2, p < 0.001]. If return of spontaneous circulation was achieved pre-hospital, there was no difference in survival. It is unclear what factors, such as more interventional cardiology or therapeutic hypothermia, made the difference in the critical care centres.
Impact of transport to critical care medical centers on outcomes after
out-of-hospital cardiac arrest
Resuscitation. 2010 May;81(5):549-54
Distance to hospital did not affect arrest survival
In a study of over 7500 patients with cardiac arrest transported by EMS in the United States, transport distance was not associated with survival on logistic analysis (OR 1.00; 95% CI 0.99–1.01).
A geospatial assessment of transport distance and survival to discharge in out of
hospital cardiac arrest patients: Implications for resuscitation centers
Resuscitation. 2010 May;81(5):518-23
Current Controversy in RSI
A review article in Anesthesia and Analgesia provides a summary of the literature surrounding RSI controversies.
- Should a pre-determined dose of induction drug be given or should it be titrated to effect prior to giving suxamethonium?
- Should fast acting opioids be coadministered to blunt the pressor response?
- What is the optimal dose of suxamethonium?
- Should defasciculating doses of neuromuscular blocking drugs be given?
- What is the ‘priming’ technique with rocuronium and is it necessary?
- Is it really bad to bag-mask ventilate the patient after induction prior to intubation? Which patients might this benefit?
- Should patients with full stomachs be anaesthetised sitting up, supine, or head down?
- Is cricoid pressure a good or a bad thing?
Not surprisingly the jury is still out on these, which is of course why they remain ‘controversies’. The review article provides a readable, interesting, and up to date summary of the evidence to date.
Rapid Sequence Induction and Intubation: Current Controversy
Anesth Analg. 2010 May 110(5):1318-25
Kids need 'proper' CPR if non-cardiac cause of arrest
The American Heart Association recommends cardiopulmonary resuscitation (CPR) by bystanders with chest compression only for adults who have cardiac arrests, but not for children. These recommendations have new support in a large observational study from Japan examining outcomes in 5170 out-of hospital paediatric arrests over a 3 year period.
For children who had out-of-hospital cardiac arrests from non-cardiac causes, conventional CPR (with rescue breathing) by bystander was associated with improved outcomes compared with compression-only CPR (7·2% [45/624] favourable one month neurological outcome vs 1·6% [6/380]; OR 5·54, 2·52–16·99). In children who had arrests of cardiac causes conventional and compression-only CPR were similarly effective. Infants < 1 year had uniformly poor outcomes.
An editorial points out that this is the largest study that has analysed out-of-hospital cardiac arrest in children, and the overall survival of 9% with only 3% of children having a good neurological outcome, is consistent with previous reports.
Conventional and chest-compression-only cardiopulmonary resuscitation by bystanders for children who have out-of-hospital cardiac arrests: a prospective, nationwide, population-based cohort study
Lancet. 2010 Apr 17 345:1347-54
2000 vs 2005 VF guidelines: RCT
One of the key changes in international resuscitation guidelines between the 2000 and 2005 has been to minimise potentially deleterious hands-off time, so that CPR is interrupted less for pulse checks and DC shocks.
These two approaches have been compared in a randomised controlled trial of 845 patients in France requiring out of hospital defibrillation, in which the control group were shocked using AEDs with prompts based on the 2000 guidelines (3 stacked shocks before CPR resumed, and pulse checks done), and the intervention group were shocked using devices that prompted according to the 2005 guidelines, in which there were fewer and shorter intervals for which the AED required the rescuer to stay clear of the patient (single shocks, no pulse checks).
There was no difference in the primary endpoint of survival to hospital admission (43.2% versus 42.7%; p=0.87), or in survival to hospital discharge (13.3% versus 10.6%; p=0.19). The study was not powered to assess one year survival. In the authors’ words: “our randomized controlled trial now provides more definitive evidence that this combination of Guidelines 2005 CPR protocol changes does not measurably improve outcome. Although the protocol changes accomplish the desired effect of increasing chest compressions, they may also cause other effects, such as earlier refibrillation and more time spent in VF, with as yet unknown consequences.”
Interestingly the Cardio-pump was used in this study to provide chest compressions, which is an active compression-decompression device, potentially limiting the generalisability of the findings to manual compression-only CPR situations. Potential bias was also introduced by the exclusion of patients in whom consent from relatives was not obtained. Nevertheless it’s good to see such rigorous clinical research applied to this area.
DEFI 2005. A Randomized Controlled Trial of the Effect of Automated External Defibrillator Cardiopulmonary Resuscitation Protocol on Outcome From Out-of-Hospital Cardiac Arrest
Circulation. 2010;121:1614-1622
Battlefield resuscitation
An excellent review of the current British military practice to prevent and treat the acute coagulopathy of trauma shock (ACoTS) describes pathophysiology and treatment options and offers an algorithm for management. Key components of the system (when indicated according to their algorithm) outlined include:
- Pre-hospital damage control shock resuscitation by a forward medical team, consisting of RSI with reduced dose thio or ketamine with suxamethonium or rocuronium, large bore sublclavian access, and early use of warmed blood products
- 1:1:1 packed red cells, fresh frozen plasma, and platelets,
- Cryoprecipitate
- Tranexamic acid
- Recombinant activated factor VII
- Permissive hypotension aiming for a systolic BP of 90 mmHg, using blood products and avoiding vasopressors according to a ‘flow rather than pressure’ philosophy
- Avoiding hypothermia by giving warmed blood products and employing active patient warming methods
- Buffering acidosis using Tris-hydroxymethyl aminomethane (THAM), which may be superior to bicarbonate by not affecting minute ventilation or coagulation, and maintaining its efficacy in hypothermic conditions
- Minimising hypoperfusion with an anaesthetic strategy that provides effective analgesia and vasodilation, using high dose fentanyl and a low concentration volatile agent
- Using fresh whole blood for resistant coagulopathy
Battlefield resuscitation
Curr Opin Crit Care. 2009 Dec;15(6):527-35
Sorting ABCD issues pre-hospital
Prospectively collected data on 727 major trauma patients from a Portugese trauma centre registry enabled the comparison of mortality between three groups of patients with a priori defined life threatening ‘ABCD’ problems: those whose ABCD issues were treated in the field by a pre-hospital emergency physician, those that were treated at another hospital prior to trauma centre transfer, and those whose ABCD issues were first treated on arrival at the trauma centre. The study population included mixed urban and rural trauma.
Patients from the pre-hospital and first hospital groups had 20% and 27% mortality respectively, compared to 38% among those whose life-threatening events were corrected only at the trauma centre.
Patients whose life- threatening events were treated in the pre-hospital environment had lower mortality but at the same time were younger and less severely injured, so a multivariate logistic regression was performed to adjust the odds of death to patient characteristics and trauma severity as well as time from accident to trauma centre. Logistic regression showed that increases in mortality were associated with female gender and older age, penetrating type of trauma, higher anatomic severity (ISS), higher physiological severity (RTS) and having the life-threatening events corrected only at the trauma centre. Logistic regression showed that patients whose life-threatening events were corrected only at the trauma centre had an odds of death 3.3 times greater than those from the pre-hospital group, adjusted for patient and trauma characteristics and time to trauma centre.
Correcting life-threatening events pre- trauma centre (pre-hospital and first hospital) increased the total time from the accident to trauma centre, but long pre-hospital times were not associated with worse outcome.
The importance of pre-trauma centre treatment of life-threatening events on the
mortality of patients transferred with severe trauma
Resuscitation. 2010 Apr;81(4):440-5
Spine immobilisation in penetrating trauma
In a retrospective study of 45,284 penetrating trauma patients, unadjusted mortality was twice as high in the 4.3% of patients who underwent spine immobilisation, compared with those who were not immobilised.
An accompanying editorial comments: ‘The number needed to treat with spine immobilization to potentially benefit one penetrating trauma patient was 1,032. The number needed to harm with spine immobilization to potentially contribute to one death was 66.‘
Spine immobilization in penetrating trauma: more harm than good?
J Trauma. 2010 Jan;68(1):115-20