Life Threatening Asthma - Some Pearls and Pitfalls

My talk on Life Threatening Asthma talk in 2nd NECCS Ipoh

Life Threatening Asthma - Some Pearls and Pitfalls from Chew Keng Sheng

Some may not agree with the ventilation strategy I borrowed from Scott Weingart's, i.e., a PEEP of 0 or zEEP.  I guess if you are familiar on how to play around with the PEEP in severe airway obstruction without causing a disaster in barotrauma, then go ahead. But to be on the safe side, I'll stick with the strategy mentioned by Scott Weingart. Listen to the 2nd podcast listed below on Dominating the Vent: Part II for a clearer picture.

Here are the compilation of podcasts and lectures I referred to prepare the talk on asthma:
1. Scott Weingatt's Dominating the Vent: Part I
Download mp4 lecture: http://emcrit.org/lectures/vent-part-1/

2. Scott Weingatt's Dominating the Vent: Part II
Download mp4 lecture: http://emcrit.org/podcasts/vent-part-2/

**These 2 lectures are very easy to understand and form the basis of ventilation strategy in ED in general. Some people may not agree with Weingart's strategy. Different people have different opinion but Weingart's strategy is very simple - only two strategies that you need to concern in ED: obstructive strategies and lung protective strategies. Even if patient initially does not have lung injuries, ARDS, ALI, the patient may eventually end up with some form of lung injuries if ventilation strategies not appropriate. So, treat the patient as if having a lung injury. Only 4 settings to adjust in ED: TV, IFR, PEEP/FiO2 (use ARDSnet table) and RR.
Notes in pdf is available for download

3. Scott Weingart - Severe asthmatic podcast
http://emcrit.org/podcasts/severe-asthmatic/

4. Scott Weingart - Coding Asthmatic
http://emcrit.org/podcasts/finger-thoracostomy/

5. Management of the Crashing Asthmatic
http://rebelem.com/rebelcast-crashing-asthmatic/

6. RAGE session 3 on life threatening asthma
http://ragepodcast.com/rage-session-three/
And RAGEBack session 3: http://ragepodcast.com/?s=asthma

And here are some of the articles referred to:
1 Oddo M, Feihl F, Schaller MD, et al. Management of mechanical ventilation in acute severe asthma: practical aspects. Intensive Care Med 2006;32(4):501-10.  

http://link.springer.com/article/10.1007%2Fs00134-005-0045-x 

2. Alvarez GG, Schulzer M, Jung D, et al. A systematic review of risk factors associated with near-fatal and fatal asthma. Can Respir J 2005;12(5):265-70.

http://www.pulsus.com/journals/abstract.jsp?sCurrPg=journal&jnlKy=4&atlKy=870&isuKy=357&isArt=t

3. Restrepo RD, Peters J. Near-fatal asthma: recognition and management. Curr Opin Pulm Med 2008;14(1):13-23

http://tinyurl.com/ns4nrnh

4. The 3Mg-Trial on the use of MgSO4

Goodacre S, Cohen J, Bradburn M, et al. The 3Mg trial: a randomised controlled trial of intravenous or nebulised magnesium sulphate versus placebo in adults with acute severe asthma. Health Technol Assess 2014;18(22):1-168
http://tinyurl.com/q9cx9va

Emergency Medicine Digest

1. Prolonged QTc in diabetic ketoacidosis in children

QTc was shown to be prolonged in up to 47% of diabetic ketoacidosis in children and tend to resolves when the ketosis clears (only 13% still with prolonged QTc after recovery).

Implication: Probably monitoring of QT interval in diabetic ketoacidosis in children can be used as a measure of the disease progression?

Reference:
Kuppermann N et al. Prolonged QT interval corrected for heart rate during diabetic ketoacidosis in children. Arch Pediatr Adolesc Med 2008 Jun; 162:544.

2. Nesiritide – Another Disappointing Trial

Nesiritide, a recombinant B-type natriuretic peptide, is approved for as an adjunct for management of acute decompensated heart failure because of its vasodilatory and natriuretic effects.

Previously Follow-Up Serial Infusions Of Nesiritide FUSION I study – shows no benefit from intermittent nesiritide infusions in outpatients with heart failure.

Now, FUSION II study – again shows no benefit of intermittent outpatient nesiritide infusions in high-risk advanced heart failure patients (those in NYHA Class IV, EF 25%). In fact, those with nesiritide has more side effects of hypotension.

Implication:
Initially, when nesiritide was approved for acute heart failure use, I thought that in the future, nesiritide will become a standard drug in all major government (KKM) hospitals and university hospitals. But, well, now that there are more and more disappointing trials, probably this may not become a reality.

Reference:
Yancy CW et al. for the FUSION II Investigators. Safety and efficacy of outpatient nesiritide in patients with advanced heart failure: Results of the Second Follow-Up Serial Infusions of Nesiritide (FUSION II) trial. Circ Heart Fail 2008 May; 1:9.

3. Noninvasive Ventilation (NIV) was shown to be safe and effective as an alternative to immediate endotracheal intubation in acute decompensated heart failure in a retrospective trial.

In fact, the likelihood of in-hospital death was significantly less in the successful-NIV group than in the intubation group. But once the NIV failed (and ultimately required intubation), there is no significant difference in the in-hospital death as compared with those who were intubated earlier.

Implication:
Probably we should put more patients on NIV early (especially those that we anticipate might require respiratory support) but we must be committed to vigilantly and closely observe the patients.

Reference:
Tallman TA et al. Noninvasive ventilation outcomes in 2,430 acute decompensated heart failure patients: An ADHERE registry analysis. Acad Emerg Med 2008 Apr; 15:355.

4. Uninterrupted Manual Chest Compressions During Biphasic Defibrillation?

In this trial, a group of researchers found that that pausing CPR for delivery of shocks might not be necessary because the risk to the rescuer is minimal.

What they did was they measured the leakage voltage and current through mock rescuers while they were still compressing the chests of 43 patients who were receiving external biphasic shocks.

No shocks were perceptible to rescuers (even during delivery of 360 J) and the leakage current measured was found to be below the recommended safety standards.

Implication:
Even though this small trial shows the risk if minimal, I am not sure if anyone of us would be ready to ignore the “one I’m clear, two you’re clear, three everybody clear!” command. One should also remember that the pads used were the pre-gelled electrodes while we were still using the manually applied gel on the electrode pads – when the gel get smeared here and there, I don’t think it is that safe to continue CPR while shock is being delivered.

Reference:
Lloyd MS et al. Hands-on defibrillation: An analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation. Circulation 2008 May 13; 117:2510.