Detection of Expiratory Flow Limitation by Manual Compression of the Abdominal Wall

Abstract

We have assessed a new method, manual compression of the abdominal wall (MCA) during expiration, in the detection of expiratory flow limitation. Twelve stable patients with chronic obstructive pulmonary disease (COPD) and five normal subjects were studied during spontaneous breathing in the supine and seated posture. MCA was performed during expiration with one hand at the umbilical level and we measured flow, volume, pleural (Ppl) and gastric (Pga) pressures and abdominal anteroposterior (AP) diameter at the umbilical level with magnetometers. No increase in expiratory flow during MCA relative to the preceding breath despite associated increases in pressures was considered as indicating expiratory flow limitation. In seven additional patients with increased upper airway collapsibility (obstructive sleep apnea syndrome [OSAS]), MCA was compared with negative expiratory pressure (NEP). In normal seated subjects, MCA was associated with a decrease in abdominal AP dimension (mean +/- SD: -27 +/- 6%), an increase in Pga (14.7 +/- 7.4 cm H(2)O) and Ppl (6.2 +/- 2.2 cm H(2)O), and an increase in expiratory flow. MCA caused similar changes in abdominal AP dimension and pressures in seated patients with COPD but six of them (50%), including four patients with FEV(1) less than 1 L, had no increase in expiratory flow. In the supine posture, MCA always increased expiratory flow in normal subjects but four additional patients with COPD showed evidence of flow limitation. MCA invariably increased expiratory flow in patients with OSAS whereas the NEP method suggested flow limitation in some cases. We conclude that MCA is a very simple method that allows detection of flow limitation in different positions.

Physiological techniques for detecting expiratory flow limitation during tidal breathing

“…Workers in Brussels, Belgium have shown that manual compression of the abdomen coinciding with the onset of expiration can be used as a simple way of detecting flow limitation at rest [57] and during exercise [58]. With one hand placed on the lower back of the patient and other applied with the palm at the level of the umbilicus perpendicular to the axis between the xiphoid process and the pubis, the operator first detects a respiratory rhythm by gentle palpation and then after warning the subject applies a forceful pressure at the onset of expiration.…”

Assessment of Factors Related to Auto-PEEP

“…The diagnosis of flow limitation with the manual compression of the abdominal maneuver is simple, does not require any device (apart from the availability of the flow-volume loop), and has been validated in spontaneously breathing subjects and in sedated mechanically ventilated subjects. [15][16][17] We measured auto-PEEP after a reasonably long endexpiratory pause (4 min) in order to reach an unambiguously stable value of auto-PEEP when trapped gas gradually decompresses into the central airways. 1 Therefore, auto-PEEP measurements should be reliable even in patients with severe inhomogeneous lung disease and long time constants.…”

“…14 After the occlusion maneuvers, the presence of flow limitation was assessed with manual compression of the abdomen. [15][16][17] Briefly, the investigator put one hand gently on the abdominal wall of the subject with the palm on the umbilicus oriented perpendicularly to the axis between the xiphoid process and the pubis. After a short period, which allowed for recognition of the expiratory phase, the investigator exerted firm but gentle compression of the abdomen in an antero-posterior direction as soon as the insufflation was finished.…”

Partial flow/volume curves and airway resistances in obese subjects: new tools for investigating flow limitation?

“…The NEP (negative expiratory pressure) technique is widely used to diagnose EFL. It does however require a specific device, and in obese patients has some drawbacks [2,7,8]. PSCs do not require specific devices, but the patient must be very cooperative [4].…”