ANZCTR - Registration

The ANZCTR website will be unavailable from 1pm until 3pm (AEDT) on Wednesday the 30th of October for website maintenance. Please be sure to log out of the system in order to avoid any loss of data.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers

Trial registered on ANZCTR

Registration number

ACTRN12616001501437

Ethics application status

Approved

Date submitted

1/10/2016

Date registered

28/10/2016

Date last updated

10/10/2017

Type of registration

Prospectively registered

Titles & IDs

Public title

Ultrasound assessment of the diaphragm in healthy volunteers

Scientific title

Evaluation of normal values for assessment of the diaphragm through ultrasonography in a healthy population

Secondary ID [1]

None

Universal Trial Number (UTN)

U1111-1188-1886

Trial acronym

Healthy Diaphragm US

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Diaphragm ultrasound assessment

Respiratory Muscles

Condition category

Condition code

Respiratory

Normal development and function of the respiratory system

Intervention/exposure

Study type

Observational

Patient registry

False

Target follow-up duration

Target follow-up type

Description of intervention(s) / exposure

After meeting all inclusion and no exclusion criteria, healthy volunteers are asked to undergo to ultrasound assessment of the diaphragm. While normally breathing, at rest, the investigator checks if none of both emi-diaphragm is affected by palsy or by some paradoxical motion.
Therefore, two types of measurement are record: 1) the cranio-caudal displacement and 2) the thickening fraction.

The cranio-caudal displacement is performed using a 3.5–5 MHz probe. The probe is placed immediately below the right or left costal margin in the midclavicular line, or in the right or left anterior axillary line and is directed medially, cephalad and dorsally, so that the ultrasound beam reaches perpendicularly the posterior third of the corresponding hemidiaphragm. The two-dimensional (2D) mode is initially used to obtain the best approach and select the exploration line; the M-mode is then used to display the motion of the anatomical structures along the selected line.
Patients are scanned along the long axis of the intercostal spaces, with the liver serving as an acoustic window to the right, and the spleen to the left. Normal inspiratory diaphragmatic movement is caudal, since the diaphragm moves toward the probe; normal expiratory trace is cranial, as the diaphragm moves away from the probe. In the M mode, the diaphragmatic excursion (displacement, cm), the speed of diaphragmatic contraction (slope, cm/s), the inspiratory time (Tinsp, s) and the duration of the cycle (Ttot, s) can be measured (Matamis et al. Intensive Care Med (2013) 39:801–810).

The thickening fraction is evaluated in the zone of apposition of the diaphragm to the rib cage. The zone of apposition is the area of the chest wall where the abdominal contents reach the lower rib cage. In this area, the diaphragm is
observed as a structure made of three distinct layers: a non-echogenic central layer bordered by two echogenic layers, the peritoneum and the diaphragmatic pleurae. To obtain adequate images of diaphragmatic thickness in M mode and 2D mode, a linear high-frequency probe (C10 MHz) is necessary. The diaphragmatic thickness can be measured during quiet spontaneous breathing and during a maximal inspiratory and expiratory effort. An index of diaphragmatic thickening, the thickening fraction (TF) can be calculated using the M mode (TF = thickness at endinspiration - thickness at end-expiration/thickness at end-expiration) (Matamis et al. Intensive Care Med (2013) 39:801–810).

Intervention code [1]

Not applicable

Comparator / control treatment

No control group

Control group

Uncontrolled

Outcomes

Primary outcome [1]

To report the normal values of the diaphragm thickening fraction in correlation with height

Timepoint [1]