Regarding hypoxic respiratory failure due to ARDS:
a) Outline four different methods you may use to determine what PEEP to set as part of the ventilatory management.
b) List four patient factors that might impact your PEEP setting.
Aim: To explore the candidate knowledge of ventilation strategies.
Key sources include: Paper 2016.2 Q 29. TE Oh Ed 8 Chpt 31 Mechanical ventilator support Chpt 33 ARDS. CanMEDS Medical Expert
Discussion: The successful candidate was able to outline four different methods and provide details of each method to guide the ventilatory management strategy for best PEEP. Candidates who listed four methods without explanation scored less marks. f they were familiar with the glossary of terms. For example, outlining methods included explanations of compliance curves, supporting evidence for methods of PEEP titration (for example ARDSnet tables or PHARLAP) or a discussion of oesophageal balloon use in the titration of PEEP. Inclusion of these methods and the rationale improved the depth of answer and scored more marks.
The college refer to Question 29 from the second paper of 2016, which asked almost exactly the same sort of questions. For the first section, one may have chosen any four from the following menu of possibilities:
The lazy man's classification of sodium disturbances was basically designed to answer this sort of differential-generating exercise. The stem of the question gives you nausea vomiting and slurred speech, which might either indicate that the examiners wanted you to suspect hypovolemia, or to explain why the hypertonic saline is indicated (symptomatic hyponatremia), or to suggest that some sort of sinister intracranial horror is quietly lurking. so, the list of differentials would therefore incorporate:
"patient factors that might impact your PEEP setting" is a novel take on this SQ, and called for extra thinking; but not too much extra thinking, as there was only 20% of the mark to be gained. The question is really asking, "where might you not be able to use a PEEP as high as you might want, and where might you need to use a higher PEEP than you might be usually comfortable with?" A list like this was probably in order, where only four options were expected:
Gattinoni, Luciano, Eleonora Carlesso, and Massimo Cressoni. "Selecting the ‘right’positive end-expiratory pressure level." Current opinion in critical care 21.1 (2015): 50-57.
Grasso, Salvatore, et al. "ARDSnet ventilatory protocol and alveolar hyperinflation: role of positive end-expiratory pressure." American journal of respiratory and critical care medicine 176.8 (2007): 761-767.
Suter, Peter M., H. Barrie Fairley, and Michael D. Isenberg. "Optimum end-expiratory airway pressure in patients with acute pulmonary failure." New England Journal of Medicine 292.6 (1975): 284-289.
Pintado, María-Consuelo, et al. "Individualized PEEP setting in subjects with ARDS: a randomized controlled pilot study." Respiratory care 58.9 (2013): 1416-1423.
Chiumello, Davide, and Matteo Brioni. "Severe hypoxemia: which strategy to choose." Critical Care 20.1 (2016): 1.