Table 3 Intervention characteristics, outcomes and main results of the studies included in the systematic review
Study | Interventions by group/side | NMES parameters | Outcomesa(tools) | Main results | |
|---|---|---|---|---|---|
C | N | ||||
Abdellaoui et al.[42] | ALM + sham NMES to quadriceps and hamstrings | ALM + NMES to quadriceps and hamstrings (BL): 60 min/day × 5 days/week × 6 weeks | Frequency: 35 Hz | Muscle strength (dynamometry) | Quadriceps strength increased more for N than C (p < 0.01) |
Pulse duration: 400 μs | |||||
Intensity: 15-32 mA for quadriceps, 22-47 mA for hamstrings (start-end) | |||||
Gerovasili et al.[25] | Usual care | Usual care + NMES to quadriceps and peroneus longus (BL): 55 min/day × 8 days | Frequency: 45 Hz | Muscle thickness (US) | Rectus femoris and vastus intermedius (right side) thickness decreased less for N than C (p < 0.05); d = 0.11-0.39 (small-moderate) |
Pulse duration: 400 μs | |||||
On-off ratio: 12-6 s | |||||
Intensity: 37-38 mA (mean) | |||||
Gruther et al.[43] | Sham NMES | NMES to quadriceps (BL): 30-60 min/day × 5 days/week × 4 weeks | Frequency: 50 Hz | Muscle thickness (US) | Quadriceps thickness increased only for N (long-term patients) (p < 0.13); d = 0.36 (moderate) |
Pulse duration: 350 μs | |||||
On-off ratio: 8-24 s | |||||
Intensity: tolerance | |||||
Karatzanos et al.[34] | Usual care | Usual care + NMES to quadriceps and peroneus longus (BL): 55 min/day × 7 days/week until ICU discharge | Frequency: 45 Hz | Muscle strength (MRC) | MRC scores for wrist flexion, hip flexion, ankle dorsiflexion (p < 0.05) and knee extension (p < 0.01) were greater for N than C |
Pulse duration: 400 μs | |||||
On-off ratio: 12-6 s | |||||
Intensity: motor threshold | |||||
Poulsen et al.[44] | Contralateral side acted as control | NMES to quadriceps (UL): 60 min/day × 7 days | Frequency: 35 Hz | Muscle volume (CT) | Quadriceps volume decreased for both C and N, with no difference between sides (p = 0.1) |
Pulse duration: 300 μs | |||||
On-off ratio: 4-6 s | |||||
Intensity: motor threshold | |||||
+50% (adjusted daily) | |||||
RodrÃguez et al.[45] | Contralateral side acted as control | NMES to biceps brachii and quadriceps (UL): 2 × 30 min/day × 13 days | Frequency: 100 Hz | Muscle strength (MRC) | MRC scores for elbow flexion (p = 0.005) and knee extension (p = 0.034) were greater for N than C. Biceps thickness was unchanged |
Pulse duration: 300 μs | |||||
On-off ratio: 2-4 s | Muscle thickness (US) | ||||
Voltage: 20-200 V | |||||
Routsi et al.[35] | Usual care | Usual care + NMES to quadriceps and peroneus longus (BL): 55 min/day × 7 days/week until ICU discharge | Frequency: 45 Hz | Muscle strength (MRC) | Global MRC score was greater for N than C (p = 0.04) |
Pulse duration: 400 μs | |||||
On-off ratio: 12-6 s | |||||
Intensity: motor threshold | |||||
Zanotti et al.[46] | ALM: 5 days/week × 4 weeks | ALM + NMES to quadriceps and glutei (BL): 25-30 min/day × 5 days/week × 4 weeks | Frequency: 8-35 Hz | Muscle strength (MRC) | MRC score increased more for N than C (p < 0.02); d = 1.44 (large) |
Pulse duration: 250-350 μs | |||||
Intensity: motor threshold | |||||