Author(s): GUERRA-VEGA, P.1, GUZMÁN, R.2, BETANCOURT, C.2, GRAGE, M.1, VERA, C.2, ARTIGAS-ARIAS, M.3, MUÑOZ-COFÉ, R.3, VITZEL, K.F.4, MARZUCA-NASSR, G.N.3, Institution: UNIVERSIDAD DE LA FRONTERA, Country: CHILE, Abstract-ID: 1735

INTRODUCTION:
Low-frequency neuromuscular electrical stimulation (NMES) attenuates the loss of functional capacity of Intensive Care Unit (ICU) patients. However, it has been shown that medium-frequency may be better than low-frequency NMES for the maintenance of strength, skeletal muscle mass and physical performance in healthy subjects. This study compares the effects of low- and medium-frequency NMES, along with a standard physical therapy (SPT) program, on functional capacity in critically ill patients.
METHODS:
Fifty-four critically ill patients admitted into ICU and on mechanical ventilation participated in this randomized clinical trial. Participants were allocated to one of the following groups: Control Group, received a standard lower limb SPT program, 2x/day; Low-frequency NMES Group, received lower limb SPT+NMES in the quadriceps muscle at 100 Hz, 2x/day; and Medium-frequency NMES Group, received lower limb SPT+NMES in the quadriceps muscle at 100 Hz and carrier frequency of 2500 Hz, 2x/day while at ICU. Interventions were concluded when sedation cessation procedures were implemented. The functional capacity outcomes were muscle strength (MRC-SS), handgrip strength (dynamometry), thickness and quality of the quadriceps muscle (ultrasonography), functional status (FSS-ICU), degree of independence for activities of daily living (Barthel Index), functional mobility and dynamic balance (Timed Up and Go Test), and quality of life (SF-36) during hospital stay. Total days of hospitalization were also recorded.
RESULTS:
Both low- and medium-frequency NMES in combination with SPT were effective strategies to improve functional capacity when compared with control group during hospital stay. Compared with low-frequency, medium-frequency NMES provided additional improvements on dynamic balance (TUG test, P<0.001), in the degree of independence to perform activities of daily living (Barthel Index, P<0.001) and quality of life (SF-36, P<0.001) prior to hospital discharge. It also promoted larger gains on functional status (FSS-ICU, P<0.05) prior to ICU discharge and in knee extension strength (MRC-SS, P<0.05) prior to intermediate care unit discharge. Finally, medium-frequency NMES induced a persistent improvement in handgrip strength earlier than low-frequency NMES (prior to intensive and intermediate care unit discharges and prior to hospital discharge) when compared with control group. Those effects could explain why the medium-frequency NMES was the only intervention to reduce total duration of hospital stay (from ICU admission to hospital discharge) in comparison to control group (P<0.05). Quadriceps muscle thickness and quality did not decrease in ICU when using either of the two NMES protocols.
CONCLUSION:
Medium-frequency NMES along with a SPT program in critically ill patients showed greater benefits on functional capacity during recovery than low-frequency NMES, despite similar effects on the prevention of quadriceps muscle mass loss.

Clinical trial registration: NCT05287919.