Table 1 Tricks and troubleshooting

Proper placement

(1) Placement depth: Usual depth is 33–40 cm (a good starting point is 37 cm)

(2) Balloon inflation: Use a balloon with a consistent working volume. Optimization of volume otherwise will need to be done by measuring the pressure–volume characteristics of the balloon itself which is not always feasible

(3) Cardiac oscillations: Cardiac oscillations should be present to confirm placement posterior to the heart above the diaphragm

(4) End-Expiratory Hold Chest Pushes: Pes and Pao should increase in equal measures with chest push resulting in no change in P_L

(1) Depth is incrementally adjusted while looking for oscillations and doing chest pushes

(2) Depending on body habitus and the unique patient, the amplitude of oscillations may be widely variable

(3) If patient is ACTIVELY breathing, expiratory breath holds can still confirm placement. Pao and Pes DECREASES in this case without change in P_L

PEEP titration

(1) Measurement of Pes and PL during expiratory holds

(2) Adjust PEEP until PL at end –expiration = zero

(3) We use in most patients with moderate-severe ARDS

(4) Especially useful with obesity or abdominal hypertension

(1) We no longer use the sliding scale FiO₂—P_L used in the EPVent studies, targeting P_L = zero with acceptable range from -2 to + 2 cmH2O

Monitoring cyclic and total lung stress

(1) Measure end-inspiratory PL: This measurement is obtained when the plateau pressure is measured during an inspiratory breath hold. We keep the end-inspiratory PL < 20cmH2O and ideally aim for < 15cmH2O to provide additional safety

(2) Measure ∆P_L: Calculated as the end-inspiratory PL minus the end expiratory PL. This provides a more targeted driving pressure measurement than the respiratory system values, and we aim for less than 10–12cmH₂O

(3) Targeted titration of tidal volume if above target values if allowable with ventilation requirements

(1) With large cardiac oscillations, use the diastole phase for measurements to be consistent

(2) We recommend PEEP titration/optimization to maximize compliance prior to targeted tidal volume reduction

Dyssynchrony and neuromuscular blockade

(1) This is easiest with systems that integrate xy plots

(2) This is more advanced level application and beyond routine use as above

(1) Not recommended for routine use as requires more specialty equipment and training