A 65-year-old male is in ICU following an out of hospital cardiac arrest secondary to a large anterior ST elevation myocardial infarction. His ICU stay has been complicated by aspiration pneumonia. He is now day 14 from admission, with a tracheostomy in situ, and has started weaning from the ventilator.
You have been asked to review him as he is communicating that he 'can't get enough air' despite on-going mechanical ventilatory support.
Outline your approach to this problem.
Urgent attention to A, B, C – Give 100% oxygen and exclude/treat immediate threats to life.
Focused history and examination considering differential diagnoses:
Airway / trache – blocked, displaced or too small diameter
Respiratory e.g. pneumonia, PE, PTX
Cardiac – ongoing ischaemia, cardiac failure, fluid overload
Neuromuscular – weakness, fatigue
Central – increased respiratory drive, pain, agitation
Triggering threshold too high
Inspiratory flow rate too low
Prolonged inspiratory time
Inadequate pressure support
Inadequately set tidal volume
100% O2, suction trache, exclude obstruction/malposition, end tidal CO2 etc.
Mode, respiratory rate and pattern
Spontaneous and delivered TV / MV / airway pressures
Expiratory flow-time curve, PEEPi (if possible)
Titrated pain relief
May need to carefully sedate to gain control of the situation if he is very distressed and agitated. Rarely need to paralyse after sedation
Basic Investigations – e.g. ABG, ECG, CXR, cultures
Further investigations as indicated – e.g. Echo, CTPA, BNP, Troponin etc.
Management of underlying cause:
Change trache if indicated
Consider change ventilator settings or mode
Increase pressure support etc
ACV Vs SIMV Vs BiLevel
An acceptable answer included the following elements:
Address causes of dyssynchrony
Approach to management
Additional Examiners‟ Comments:
Most candidates put together a reasonable answer. Some treated it only as a blocked airway question. Many were not well organised for such a common and important clinical question that has been asked previously. Few candidates thought broadly.
Apart from slightly different wording, this question closely resembles Question 4 from the second paper of 2012. The discussion section from that question is therefore reporduced below, with minimal modification.
This question lends itself well to a systematic approach.
Jairo I. Santanilla "The Crashing Ventilated Patient"; Chapter 3 in Emergency Department Resuscitation of the Critically Ill, American College of Emergency Physicians, 2011.