Oesophageal pressure as a surrogate of pleural pressure in mechanically ventilated patients

Abstract

BackgroundEsophageal pressure (Pes) is used to approximate pleural pressure (PPL) and therefore to estimate transpulmonary pressure (PL).ObjectivesWe aimed to compare esophageal and regional pleural pressures and to calculate transpulmonary pressures in a prospective physiological study on lung transplant recipients during their stay in the intensive care unit of a tertiary university hospital.MethodsLung transplant recipients receiving invasive mechanical ventilation and monitored by esophageal manometry and dependent and non-dependent pleural catheters were investigated during the post-operative period. We performed simultaneous short time measurements and recordings of esophageal manometry and pleural pressures. Expiratory and inspiratory PL were computed by subtracting regional PPL or Pes from airway pressure; inspiratory PL was also calculated with the elastance ratio method.ResultsSixteen patients were included. Among them, 14 were analyzed. Esophageal pressures correlated with dependent and non-dependent pleural pressures during expiration, respectively R2=0.71, p=0.005 and R2=0.77, p=0.001 and during inspiration, respectively, R2=0.66 for both (respectively p=0.01 and p=0.014). PL calculated using Pes were close to those obtained from the dependent pleural catheter but higher than those obtained from the non-dependent pleural catheter both during expiration and inspiration.ConclusionIn ventilated lung transplant recipients, esophageal manometry is well correlated to pleural pressure. Absolute value of Pes is higher than pleural pressure of non-dependent lung regions and could therefore underestimate the highest level of lung stress in these at high risk of overinflation.

Partition of respiratory mechanics in patients with acute respiratory distress syndrome and association with outcome: a multicentre clinical study

“…Since the position of the esophagus is close to dorsal lung, we further partitioned P L specific to the ventral or dorsal lungs. Concretely, the directly measured P L represents end-expiratory P L across the dorsal lung, whereas the elastance-derived P L represents end-inspiratory P L across the ventral lung [ 10 , 11 ]. We also calculated the oxygenation stretch index [(PaO 2 /(FiO 2 × DP aw )] a previously described composite index of oxygenation and mechanics [ 15 ].…”

“…Particularly, because of the existence of pleural pressure gradient [ 8 ], P L at dorsal lung differs from P L at ventral lung, which may have different implications for monitoring VILI. For example, because the position of the esophagus is close to dorsal lung, the directly measured end-expiratory P L through esophageal pressure (Pes) provides P L at the dorsal lung, representing the degree of collapse [ 9 – 11 ]. On the other hand, the tidal change of pleural pressure is relatively uniform.…”

Personalized mechanical ventilation in acute respiratory distress syndrome

“…In mechanically ventilated non-obese patients, the average intraabdominal pressure is 13 cmH 2 O and half of intraabdominal pressure is transmitted to the thoracic cavity [27]. The following parameters have been suggested as potential targets for individualized mechanical ventilation when using P L [28,29]: Fi O2 table have not shown beneficial effects on outcomes [31,32].…”

“…In mechanically ventilated non-obese patients, the average intraabdominal pressure is 13 cmH 2 O and half of intraabdominal pressure is transmitted to the thoracic cavity [ 27 ]. The following parameters have been suggested as potential targets for individualized mechanical ventilation when using P L [ 28 , 29 ]: (1) end-inspiratory P L (non-dependent lung) below 15–20 cmH 2 O; (2) Δ P L below 10–15 cmH 2 O; (3) PEEP set at end-expiratory P L (dependent lung) equal to 0–6 cmH 2 O; and (4) P L during recruitment maneuvers not to exceed 25 cmH 2 O [ 29 , 30 ]. To date, RCTs evaluating the role of individualized PEEP set according to P L at end-expiration and compared with low or high Pa O2 /F i O2 table have not shown beneficial effects on outcomes [ 31 , 32 ].…”

Evaluation of the accuracy of established patient inspiratory effort estimation methods during mechanical support ventilation

“…The esophageal wall touches the outside pleura in this position which makes the measured esophageal pressure proportional to the pleural pressure ( Fig. 4 ) [25] , [26] , [27] . Inspiratory effort causes a negative swing in pleural pressure, and changes in the esophageal pressure ( ) can therefore be used to track changes in the inspiratory effort ( Fig.…”