High risk patients benefit from pre-operative intra-aortic balloon counterpulsation (IABP) prior to coronary artery bypass surgery. Would the same apply to patients undergoing percutaneous coronary intervention (PCI)?
A multicentre randomised controlled trial was conducted on over 300 patients with severe LV dysfunction and extensive coronary disease. The intervention was elective insertion of IABP before PCI. The composite primary end point of death, acute myocardial infarction, cerebrovascular event, or further revascularization at hospital discharge was not reduced in the intervention group.
These results do not support a strategy of routine IABP placement before PCI in all patients with severe left ventricular dysfunction and extensive coronary disease.
Elective Intra-aortic Balloon Counterpulsation During High-Risk Percutaneous Coronary Intervention
JAMA. 2010;304(8):867-874
ACE-inhibitor related angioedema
The pathophysiology of angiotensin-converting enzyme inhibitor (ACEi)–induced angioedema most likely resembles that of hereditary angioedema, ie, it is mainly mediated by bradykinin-induced activation of vascular bradykinin B2 receptors. It was hypothesised that the bradykinin B2 receptor antagonist icatibant might therefore be an effective therapy for ACEi-induced angioedema. This month’s Annals of Emergency Medicine reports research assessing its effciacy in a small series of patients, with a retrospective comparison against steroid and antihistamine therapy.
The eight patients with acute ACEi-induced angioedema were treated with a single subcutaneous injection of icatibant. First symptom improvement after icatibant injection occurred at a mean time of 50.6 minutes and complete relief of symptoms at 4.4 hours. In the historical comparison group treated with methylprednisolone and clemastine (an antihistamine / anticholinergic), the mean time to complete relief of symptoms was 33 hours. Some of these patients received a tracheotomy (3/47), were intubated (2/47), or received a second dose of methylprednisolone (12/47).
Therapeutic Efficacy of Icatibant in Angioedema Induced by Angiotensin-Converting Enzyme Inhibitors: A Case Series
Ann Emerg Med. 2010;56(3):278-82
UK Capacity Assessment Mnemonic
GPs Drs Hoghton & Chadwick have produced a bioethical mnemonic ‘CURB BADLIP’, for all healthcare professionals in England, Scotland, and Wales for use in patients aged 18 or over in an emergency:
C—communicate. Can the person communicate his or her decision?
U—understand. Can the person understand the information being given?
R—retain. Can the person retain the information given?
B—balance. Can the person balance, or use, the information?
B—best interest. If there is no capacity can you make a best interest decision?
AD—advanced decision. Is there an advanced decision to refuse treatment?
L—lasting power of attorney. Has lasting power of attorney been appointed?
I—independent mental capacity advocate. Is the person without anyone who can be consulted about best interest? In an emergency involve an independent mental capacity advocate
P—proxy. Are there any unresolved conflicts? Consider involving the local ethics committee or the court of protection appointed deputy.
Assessing patient capacity: Remember CURB BADLIP in the UK
BMJ 2010 340: c1285
Delirium guidelines
The UK’s National Institute for Health and Clinical Excellence (NICE) has produced guidelines on delirium.
Delirium (sometimes called ‘acute confusional state’) is a common clinical syndrome characterised by disturbed consciousness, cognitive function or perception, which has an acute onset and fluctuating course.
Some snippets from the guideline include:
- If indicators of delirium are identified, carry out a clinical assessment based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria or short Confusion Assessment Method (short CAM) to confirm the diagnosis.
- In critical care or in the recovery room after surgery, CAM-ICU should be used. A healthcare professional who is trained and competent in the diagnosis of delirium should carry out the assessment.
- If there is difficulty distinguishing between the diagnoses of delirium, dementia or delirium superimposed on dementia, treat for delirium first.
- If a person with delirium is distressed or considered a risk to themselves or others and verbal and non-verbal de-escalation techniques are ineffective or inappropriate, consider giving short- term (usually for 1 week or less) haloperidol or olanzapine.
The CAM-ICU assessment tool is demonstrated in the video below, which is found along with other helpful delirium resources at http://www.icudelirium.co.uk
NICE Guidance: Delirium: diagnosis, prevention and management
Compression-only CPR vs standard CPR
Two studies comparing compression-only CPR with conventional CPR:
BACKGROUND: The role of rescue breathing in cardiopulmonary resuscitation (CPR) performed by a layperson is uncertain. We hypothesized that the dispatcher instructions to bystanders to provide chest compression alone would result in improved survival as compared with instructions to provide chest compression plus rescue breathing.
METHODS: We conducted a multicenter, randomized trial of dispatcher instructions to bystanders for performing CPR. The patients were persons 18 years of age or older with out-of-hospital cardiac arrest for whom dispatchers initiated CPR instruction to bystanders. Patients were randomly assigned to receive chest compression alone or chest compression plus rescue breathing. The primary outcome was survival to hospital discharge. Secondary outcomes included a favorable neurologic outcome at discharge.
RESULTS: Of the 1941 patients who met the inclusion criteria, 981 were randomly assigned to receive chest compression alone and 960 to receive chest compression plus rescue breathing. We observed no significant difference between the two groups in the proportion of patients who survived to hospital discharge (12.5% with chest compression alone and 11.0% with chest compression plus rescue breathing, P=0.31) or in the proportion who survived with a favorable neurologic outcome in the two sites that assessed this secondary outcome (14.4% and 11.5%, respectively; P=0.13). Prespecified subgroup analyses showed a trend toward a higher proportion of patients surviving to hospital discharge with chest compression alone as compared with chest compression plus rescue breathing for patients with a cardiac cause of arrest (15.5% vs. 12.3%, P=0.09) and for those with shockable rhythms (31.9% vs. 25.7%, P=0.09).
CONCLUSIONS: Dispatcher instruction consisting of chest compression alone did not increase the survival rate overall, although there was a trend toward better outcomes in key clinical subgroups. The results support a strategy for CPR performed by laypersons that emphasizes chest compression and minimizes the role of rescue breathing. (Funded in part by the Laerdal Foundation for Acute Medicine and the Medic One Foundation; ClinicalTrials.gov number, NCT00219687.)
CPR with chest compression alone or with rescue breathing
N Engl J Med. 2010 Jul 29;363(5):423-3
BACKGROUND: Emergency medical dispatchers give instructions on how to perform cardiopulmonary resuscitation (CPR) over the telephone to callers requesting help for a patient with suspected cardiac arrest, before the arrival of emergency medical services (EMS) personnel. A previous study indicated that instructions to perform CPR consisting of only chest compression result in a treatment efficacy that is similar or even superior to that associated with instructions given to perform standard CPR, which consists of both compression and ventilation. That study, however, was not powered to assess a possible difference in survival. The aim of this prospective, randomized study was to evaluate the possible superiority of compression-only CPR over standard CPR with respect to survival.
METHODS: Patients with suspected, witnessed, out-of-hospital cardiac arrest were randomly assigned to undergo either compression-only CPR or standard CPR. The primary end point was 30-day survival.
RESULTS: Data for the primary analysis were collected from February 2005 through January 2009 for a total of 1276 patients. Of these, 620 patients had been assigned to receive compression-only CPR and 656 patients had been assigned to receive standard CPR. The rate of 30-day survival was similar in the two groups: 8.7% (54 of 620 patients) in the group receiving compression-only CPR and 7.0% (46 of 656 patients) in the group receiving standard CPR (absolute difference for compression-only vs. standard CPR, 1.7 percentage points; 95% confidence interval, -1.2 to 4.6; P=0.29).
CONCLUSIONS: This prospective, randomized study showed no significant difference with respect to survival at 30 days between instructions given by an emergency medical dispatcher, before the arrival of EMS personnel, for compression-only CPR and instructions for standard CPR in patients with suspected, witnessed, out-of-hospital cardiac arrest. (Funded by the Swedish Heart–Lung Foundation and others; Karolinska Clinical Trial Registration number, CT20080012.)
Compression-Only CPR or Standard CPR in Out-of-Hospital Cardiac Arrest
N Engl J Med. 2010 Jul 29;363(5):434-42
Cuffed vs. uncuffed tubes in kids
The debate considering cuffed vs uncuffed tracheal tubes in children continues in some centres. In my view the argument for cuffed tubes in the emergency medicine setting is much stronger.
I found an online presentation by Patrick Ross, MD, on the subject which includes a nice summary of recent literature. I like his take home message:
‘If they are coming to the ICU, if they may be difficult to ventilate, if I only want to intubate once – I use a cuffed tube’
Cuffed vs. Uncuffed ETT
Weight formula for kids
The traditional ‘APLS formula’ for weight estimation in children based on age (wt in kg = [age+4] x 2) is recognised as underestimating weight in ‘developed’ countries, with the degree of underestimation increasing with increasing age.
Several authors have attempted to derive a more accurate formula.
In the UK, the measured weights of over 93 000 children aged 1-16 who attended a paediatric emergency department were used to compare a previously derived formula (wt=3[age]+7) with the APLS formula.
The formula ‘Weight=2(age+4)’ underestimated children’s weights by a mean of 33.4% (95% CI 33.2% to 33.6%) over the age range 1–16 years whereas the formula ‘Weight=3(age)+7’ provided a mean underestimate of 6.9% (95% CI 6.8% to 7.1%); this latter formula remained applicable from 1 to 13 years inclusive.
The authors state: ‘The APLS formula has clearly become a victim of better nourished children. With a mean underestimate of more than 20% (nearly 40% at age 10 years), its place as a weight estimation tool is questionable…. To continue with an inaccurate formula with no evidence base cannot be considered good medical practice.’
Weight estimation in paediatrics: a comparison of the APLS formula and the formula ‘Weight=3(age)+7’
Emerg Med J. 2010 Jul 20. [Epub ahead of print]
A previous retrospective Australian study on over 70 000 paediatric ED attendances derived formulae for three different age ranges:
- For Infants < 12 months: Weight (kg) = (age in months + 9)/2
- For Children aged 1-5 years: Weight (kg) = 2 x (age in years + 5)
- For Children aged 5-14 years: Weight (kg) = 4 x age in years.
Make your Best Guess: An updated method for paediatric weight estimation in emergencies
Emerg Med Australas. 2007 Dec;19(6):528-34
T-piece SBT harder work
24 difficult to wean patients underwent three spontaneous breathing trials in random order, with PA catheter monitoring in place. T-piece spontaneous ventilation was compared with pressure support ventilation 7 cmH20 without PEEP, and with pressure support ventilation 7 cmH20 with 5 cmH20 PEEP. T-piece was associated with higher SBT failure rates and more patient effort, left ventricular failure, and smaller tidal volumes. The study suggests that in selected difficult-to-wean patients, clinical and physiological responses differ depending on the type of SBT used to ascertain whether or not a patient is ready for extubation. Of note, the authors did not extubate the patients who succeeded a PSV trial, because it has been shown that a spontaneous breathing trial using T-piece mimics the work of breathing performed after extubation, and an extubation failure is associated with high mortality.
Physiological comparison of three spontaneous breathing trials in difficult-to-wean patients
Intensive Care Med. 2010 Jul;36(7):1171-9
Dexmedetomidine meta-analysis
Results from 24 studies on dexmedetomidine were assessed in a meta-analysis to determine the effect on ICU length of stay. The authors concluded that the limited evidence suggests that dexmedetomidine might reduce length of ICU stay in some critically ill patients, but the risk of bradycardia was significantly higher when both a loading dose and high maintenance doses (>0.7 μg/kg/h) were used.
Use of dexmedetomidine as a sedative and analgesic agent in critically ill adult patients: a meta-analysis.
Intensive Care Med. 2010 Jun;36(6):926-39
Mallampati assessment in ED airways
In a series of approximately 300 patients intubated in the ED, operators were unable to complete a Mallampati assessment in three quarters of them, citing lack of patient cooperation and critical illness as the main reasons. This is in keeping with work by Richard Levitan, lending further support to the lack of applicability of routine pre-operative airway assessment methods in critical care.
Feasibility of the preoperative Mallampati airway assessment in emergency department patients
J Emerg Med. 2010 Jun;38(5):677-8