Electrode usability during a multiday abdominal NMES program

Development of respiratory muscle weakness is a major clinical problem in
patients that are mechanically ventilated at the intensive care unit (ICU).
Respiratory muscle weakness occurs in these patients primarily because
mechanical ventilation can partially or completely unload the respiratory
muscles, which results in the development of disuse atrophy. This is associated
with adverse outcomes, including prolonged duration of mechanical ventilation
and mortality. While considerable research within this context is focused on
the diaphragm (main inspiratory muscle), the effects of critical illness on
expiratory muscle function has not been studied. The main expiratory muscles
are the abdominal wall muscles, which are important for airway clearance and
coughing. Weakness of these muscles lead to poor cough function and
(re)hospitalization for respiratory complications.

We are currently conducting a clinical study that is focused on the prevention
of expiratory muscle weakness (NL57058.091.16, CMO 2016-2366 file at CMO
Arnhem-Nijmegen, multicenter study with VUmc). Because most patients are
sedated, they cannot participate in active physiotherapy. For this reason
neuromuscular electrical stimulation (NMES) of the expiratory abdominal wall
muscles is applied two times a day. We expect that cough function can be
maintained and that patients will wean earlier from the ventilator.

NMES uses surface electrodes to apply stimulation to muscles. For practical and
clinical reasons, we are replacing the electrodes every five days in our
ongoing clinical study (NL57058.091.16, CMO 2016-2366 file at CMO
Arnhem-Nijmegen), as renewing the electrodes on a daily basis is
time-consuming, more expensive and might negatively affect skin structure and
function. Prolonged use of the same electrodes, however, might affect the
condition of the electrode-skin contact and such NMES effectiveness. In
general, one aspect of NMES therapy that is not well described in the
literature is whether multiday use of NMES electrodes influences the
effectiveness of NMES therapy.
In the current study we aim to compare three types of electrodes to determine
which type is most suitable for multiday use. This will be evaluated in healthy
subjects so that measurements do not interfere with our study in ICU patients.
Results of the current study will be used to determine which type of electrode
is most suitable to use in future clinical studies or implementation of NMES at
the ICU.

-To determine which type of NMES electrodes is most suitable for multiday (5
days) use. The main objective is to explore the effect of time and electrode
type on skin condition during multiday use of the same electrodes in healthy
subjects.

Explorative pilot study

The expiratory abdominal wall muscles will be stimulated for two times a day
for a period of five consecutive days. This is done through similar protocols
that are used in the study in ICU-patients. The current study does not aim to
evaluate the effect of muscle stimulation on muscle mass and properties, but on
the usability/efficiency of three types of surface electrodes.

We believe that there are minimal risks associated with participation. The
study will be performed with the goal to help in decision-making regarding
multiday use of electrodes for a future clinical study / implementation.
Because this study is performed in healthy subjects within the guidelines for
use of the device and electrodes, we expect minimum risks for participating in
this study. The subject decides the stimulation intensity so that stimulation
is applied with an intensity that is comforatble for the subject. This
intensity can be changed during the stimulation sessions based on the needs of
the subject; both an increase (due to habituation) or decrease in intensity is
possible. If skin irritation occurs during stimulation sessions, stimulation
sessions will be stopped immediately.
There are several aspects of this study that could be regarded as
inconveniences to study participants. Subjects need to wear electrodes on their
skin for 5 consecutive days; during this period, subjects are asked to avoid
extensive transpiration, such as induced by strenuous exercise or sun bathing,
since this could possibly affect electrode quality. However, subjects are aware
of these inconveniences before they decide to participate in the study. There
will be small benefits for the participants, as it is known that muscle
stimulation can be beneficial in terms of improving muscle strength.