Manual compression of the abdomen to assess expiratory flow limitation during mechanical ventilation

The aim of this study was to evaluate the manual compression of the abdomen (MCA) during expiration as a simple bedside method to detect expiratory flow limitation (EFL) during daily clinical practice of mechanical ventilation (MV).

We studied 44 semirecumbent intubated and sedated critically ill patients. Flow-volume loops obtained during MCA were superimposed upon the preceding breaths and recorded with the ventilator. Expiratory flow limitation was expressed as percentage of expiratory tidal volume without any increase in flow during MCA (MCA [%V(T)]). In the first 13 patients, MCA was validated by comparison with the negative expiratory pressure (NEP) technique. Esophageal pressure changes during MCA and intrinsic positive end-expiratory pressure were also recorded in all the patients.

Manual compression of the abdomen and NEP agreed in all cases in detecting EFL with a bias of -0.16%. Percentage of expiratory tidal volume without any increase in flow during MCA is highly correlated with percentage of expiratory tidal volume without any increase in flow during NEP (n = 13, P < .0001, r(2) = 0.99) and intrinsic positive end-expiratory pressure (n = 44, P < .001, r(2) = 0.78), with a good repeatability (n = 44; within-subject SD, 5.7%) and reproducibility (n = 13; within-subject SD, 2.41%). Two third of the patients were flow limited, among whom one third had no previously known respiratory disease.

Manual compression of the abdomen provides a simple, rapid, and safe bedside reliable maneuver to detect and quantify EFL during mechanical ventilation.