Table 3.

Diaphragm ultrasonography: transducer settings and technique

Transducer settings
Excursion  The ideal range is between 2 and 5 MHz (cardiac or abdominal transducer)  The ideal mode is the M-mode  Maximum depth should be adjusted to capture maximum excursion  Gain should be adjusted to create ideal contrast with surrounding structures Thickness  The ideal range is between 7 and12 MHz (linear transducer)  No consensus was achieved for preferring B-mode or M-mode  Depth should be set just below to several centimetres under the diaphragm  Gain should be adjusted to create ideal contrast with surrounding structures
Technique
Excursion  The transducer should be aimed at the dome of the diaphragm  No consensus was achieved on transducer placement on the abdomen  Measurements are best performed in M-mode and during quiet breathing  Organ displacement is a valid alternative for excursion if the diaphragm dome is hard to visualize Thickness  The transducer should be placed on the midaxillary line or slightly more ventral, approximately between the 8th and 11th rib, with lung slightly or just not moving into the image  The transducer should be placed perpendicular to chest wall, so that all three layers (pleura, peritoneum and fibrous layer) are visible  No consensus was achieved on transducer orientation to be in line with or perpendicular to the intercostal space  Caliper placement should be as close as possible to the pleural and peritoneal line without including these lines in the measurement  No consensus was achieved on the optimal breathing pattern for making measurements Both  Unilateral measurement of the diaphragm on the right side of the patient is an acceptable proxy for the whole diaphragm, unless there is any suspicion of unilateral pathology (e.g. thoracic surgery, phrenic nerve or spinal cord injury) in which case this needs to be excluded or measurements need to be taken on both sides