Two (apparent wide complex) Rhythms in One Patient: First is at rate of 300, second at Rate of 180

A middle-aged patient with no known significant past medical history had sudden onset of  palpitations, diaphoresis, dyspnea. This lasted for roughly 30 seconds.  EMS was called and he had palpitations again and had this monitor strip (labeled as leads I, II, and III):
There is a wide complex tachycardia at a rate of 302.  There is a narrow spike at the top of each wave, suggesting rapid conduction to the ventricle.  Perhaps it is actually a narrow complex?

He was awake with a normal blood pressure and no shock.

A rate of 302 is very fast for any tachycardia in an adult, but is particularly fast for ventricular tachycardia.  The narrow spike at the beginning of each QRS suggests that the ventricle is activated through the fast conducting Purkinje system, and is probably a supraventricular rhythm.  One typical SVT that occurs at a rate of 300 is atrial flutter.  It is unusual, however, for the AV node to conduct at this rate.

No matter what the source, it is very fast.

Before this could be electrically cardioverted, the patient spontaneously converted to sinus rhythm (again, leads I, II, and III):
This shows sinus rhythm.  There is a wide complex with a deep S-wave in lead I, strongly suggesting right bundle branch block.

He arrived in the ED and had this 12-lead ECG:
Again, sinus rhythm, and with confirmation of RBBB.  No ischemia.

That the patient tolerated his rhythm of 300 is very re-assuring and makes this rhythm much less life-threatening than if he had been syncopal, hypotensive, or in shock.  It also suggests a structurally normal heart.  A patient with cardiomyopathy would not tolerate this rate.  He remained stable in the ED.

K was 3.6 mEq/L.  Mg was 1.6 mEq/L.

Thinking the patient had suffered from VT, he was started on amiodarone.

Because of worry about primary ischemia as the underlying etiology, he went to the cath lab and coronaries were normal.

An echocardiogram showed normal anatomy and function.

While in the hospital, he again had symptoms and had another ECG recorded:
This is very different from the first. 
It shows a regular wide complex tachycardia, with a left bundle branch block pattern and an inferior axis.  The rate is 180.  There are no P-waves.  The QRS duration is only 120 ms, which is quite narrow for VT.
Considerations in the diagnosis:

The electrophysiologist noted A-V dissociation in lead-II (which is nearly diagnostic of ventricular tachycardia).  I am unable to recognize it in this tracing.

An LBBB pattern by itself strongly suggests an SVT with LBBB-type aberrancy, as does the QRS duration of 120 ms.  Most typical VT (but certainly not all) has a QRS duration of  > 140.  Few typical (i.e., not fascicular) VT have a QRS as short as 120 ms.

However, the fact that the patient has RBBB at baseline, and this ECG has LBBB, makes SVT (sinus, PSVT, flutter) with LBBB-aberrancy virtually impossible.

So now we know that it is wide, LBBB, not SVT with aberrancy, and not a typical VT.  The ultrasound showing a structurally normal heart also makes typical VT unlikely. 

If you can see A-V dissociaton as the electrophysiologist did, that clinches the diagnosis of VT.  

This leaves us with the "idiopathic" ventricular tachycardias: probably fascicular VT or right ventricular outflow tract VT.  These are "idiopathic"  VT's which occur in an otherwise normal heart, and are, compared to typical VT, relatively narrow.  See these cases for a more detailed explanation of fascicular VT.

Subsequent events;

For the second rhythm, the electrophysiologist suspected right bundle branch fascicular re-entry (I had not heard of it before) because of the presence of baseline RBBB when in sinus.  

For the first rhythm, he suspected atrial flutter with 1:1 conduction.

At EP study, he was right on both counts, and underwent ablation of fascicular VT as well as cavo-tricuspid isthmus ablation to eliminate the atrial flutter loop.

The patient did very well.

Final Diagnosis:

1. Atrial Flutter at rate of 302 with 1:1 conduction and ventricular rate of 302 with RBBB.
2. Right Bundle Fascicular Re-entrant Tachycardia.






Retrieval registrar WANTED! – RFDS Cairns

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RFDS Cairns is looking for  retrieval registrars for ACEM & ACRRM accredited posts

here is the job position

Unique learning opportunities with this retrieval medicine post include :

  1. Remote medicine experience/training with Indigenous health
  2. Fixed wing and rotary wing aeromedical retrieval work
  3. Research project assistance

Previous registrars have published the following papers under my guidance

Case report of ketamine sedation during aeromedical retrieval

Description of an Assembled Noninvasive Capnography Setup

Cape York and the area around Cairns is some of the most stunning country/landscape in Australia. Enjoy flying over this beauty during your shift!

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Filed under: Aeromedical retrieval

The 3Mg Trial

Journal Club 008

Author: Adrian Cakra
Reviewer: 
Chris Nickson

Goodacre S, Cohen J, Bradburn M, Gray A, Benger J, Coats T; 3Mg Research Team. Intravenous or nebulised magnesium sulphate versus standard therapy for severe acute asthma (3Mg trial): a double-blind, randomised controlled trial. Lancet Respir Med. 2013 Jun;1(4):293-300. doi: 10.1016/S2213-2600(13)70070-5. Epub 2013 May 17. PubMed PMID: 24429154.

THE QUESTION

  • Does intravenous or nebulised MgSO4 improve symptoms of breathlessness and reduce the need for hospital admissions in adults with severe acute asthma?

STUDY DESIGN

TYPE OF STUDY

  • Multi-centre double-blind placebo-controlled three-arm randomised controlled trial

POPULATION

  • n=1,109 patients (2,783 assessed for eligibility) from 34 UK emergency departments

Inclusion criteria

  • Adults (age ≥ 16) attending an emergency department with severe asthma:
    • Peak flow < 50% predicted
    • RR > 25/min
    • HR > 110/min
    • Unable to complete a sentence in one breath

Exclusion criteria

  • Life-threatening features:
    • SaO2 <92%
    • Silent chest
    • Cyanosis
    • Poor respiratory effort
    • Bradycardia
    • Arrhythmia
    • Hypotension
    • Exhaustion
    • Coma or confusion
    • Contraindication to MgSO4 (nebulised or intravenous)
    • Inability to consent
    • Previously on 3Mg trial

INTERVENTIONS/ COMPARISONS

  • IV MgSO4 + nebulised saline, n= 339
  • IV saline + nebulised MgSO4, n= 406
  • IV saline + nebulised saline (placebo), n= 364

OUTCOMES

Primary outcomes

  • Health service outcome: proportion of patients admitted to hospital after ED treatment, or proportion of patients admitted to hospital within 7 days
    • Rates of admission did not differ between active treatment and placebo groups (OR 0.84 95% CI 0.61-1.15; p=0.276), IV MgSO4 and nebulised MgSO4 (OR 0.76 95% CI 0.53-1.10; p=0.146), IV MgSO4 and placebo (OR 0.73 95% CI 0.51-1.04; p=0.083), or nebulised MgSO4 and placebo (0.96 95% CI 0.6=5-1.40; p0.819).
  • Patient-centred outcome: visual analogue scale (VAS) for breathlessness in the 2 h after start of treatment
    • Mean improvement in VAS did not differ between active treatment and placebo groups but changes were greater in the IV MgSO4 group than the nebulised group (5.1mm, 95% CI 0.8-9.4; p= 0.019).

Secondary outcomes

  • There were no statistically significant differences in these secondary outcomes:
    • Mortality
    • Adverse events
    • Use of ventilation or respiratory support
    • Length of hospital stay
    • Admission to HDU or ICU
    • Change in peak flow and physiological variables (oxygen sats, HR, RR, BP) over 2 hours
    • Change of quality of life between baseline and 1 month
    • Number of unscheduled health-care contacts over the subsequent month
    • Satisfaction with care

COMMENTARY AND CRITICISMS

Strengths

  • Double blind RCT
  • large multi-centre study
  • reasonable baseline balance
  • pragmatic trial with most patients receiving adequate medical treatment
  • good follow up in ED
  • although there were two primary outcomes, the study was powered for both a priori

Criticisms

  • Ran out of funding – only recruited 92% target number – and slightly underpowered as a result
    • had 84% power to detect a 10% difference in admission rate for nebulised treatment versus placebo and 87% power for intravenous MgSO4 versus placebo
    • had 90% power to detect an 8 mm difference in a 100 mm VAS at 2 h after treatment initiation (two-sided α=0·05
  • High percentage of exclusions
  • low follow up at 30 days
  • Only applicable to emergency department patients
  • as a pragmatic trial, some patients may ave been misdiagnosed
  • Exclusion of life-threatening asthma, which is a particularly relevant group to ICU practitioners – these patients are highly unlikely to be included in future RCTs
  • The types of patients that typically receive IV MgSO4 in our setting are almost certainly going to be admitted to hospital regardless

Commentary

  • a possible interpretation is that magnesium may have little additional benefit if maximal bronchodilator therapy is used – IV MgSO4 may still have some role as a salbutamol sparing agent
  • previously, the MAGNETIC trial found a benefit for nebulised MgSO4 in children, it is possible that both nebulised and IV magnesium is more effective in children
  • there was one death in each of the IV and nebulised MgSO4 groups
  • there were few side-effects from nebulsied and IV MgSO4 compared to placebo (e.g. hypotension: 9% Nebulised MgSO4, 8% IV MgSO4 and 6% placebo)

FINAL WORDS

  • The 3Mg suggests there is no role for nebulised MgSO4 in adult patients with severe asthma. Although no benefit was found for IV MgSO4, there is still scope for its use in life-threatening asthma given that these patients were excluded and MgSO4 is inexpensive and has an acceptable side effect profile.

The post The 3Mg Trial appeared first on INTENSIVE.

RSI checklist from Kiwi Contributor!

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In the PHARM mailbox this month, Dr Jonathon Wills, from New Zealand, sent me his RSI checklist he had developed for his ICU and helicopter retrieval service.

He wanted to share it in the spirit of FOAMED

So check it out!

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In his email explaining the checklist I found this paragraph on implementation to be very important so reproduce it here now :

Buy-in was achieved by getting the nurses on board. I sold it to them as this is a tool that will get people doing things in the same way that maximises success. It is your tool to empower you to get doctors doing it right! They are the continuity in the retrieval service so it was important to set up a process that worked for them. It also means they have the ability to intervene early if thing go wrong because they all know what the next step is and when it should be activated.

Thanks Jono for the Kiwi contribution to FOAMEd!

 


Filed under: airway, Emergency anaesthesia, Emergency medicine and critical care, FOAMEd, Online critical airway training Tagged: checklist, kiwi, RSI

Development of a standard operating procedure and checklist for rapid sequence induction in the critically ill

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Dr Peter Sherren during Sydney HEMS days

Of late folks have been sending me their latest RSI/intubation checklists which is brilliant stuff but I came across this open access article written by Dr Peter Sherren, an ex Sydney HEMS registrar who is now a consultant anaesthetist back in UK.

The paper he writes along with his co-authors is an excellent example of checklist design in relation to intubation of the critically ill patient.

Check the full open access article here courtesy of Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine

Development of a standard operating procedure and checklist for rapid sequence
induction in the critically ill

 


Filed under: airway, Emergency anaesthesia, FOAMEd, Online critical airway training Tagged: checklist, intubation, peter-sherren, RSI