Electrical muscle stimulation prevents critical illness polyneuromyopathy: a randomized parallel intervention trial

Abstract

Introduction: Critical illness polyneuromyopathy (CIPNM) is a common complication of critical illness presenting with muscle weakness and is associated with increased duration of mechanical ventilation and weaning period. No preventive tool and no specific treatment have been proposed so far for CIPNM. Electrical muscle stimulation (EMS) has been shown to be beneficial in patients with severe chronic heart failure and chronic obstructive pulmonary disease. Aim of our study was to assess the efficacy of EMS in preventing CIPNM in critically ill patients.

Methods: One hundred and forty consecutive critically ill patients with an APACHE II score >or= 13 were randomly assigned after stratification to the EMS group (n = 68) (age:61 +/- 19 years) (APACHE II:18 +/- 4, SOFA:9 +/- 3) or to the control group (n = 72) (age:58 +/- 18 years) (APACHE II:18 +/- 5, SOFA:9 +/- 3). Patients of the EMS group received daily EMS sessions. CIPNM was diagnosed clinically with the medical research council (MRC) scale for muscle strength (maximum score 60, <48/60 cut off for diagnosis) by two unblinded independent investigators. Duration of weaning from mechanical ventilation and intensive care unit (ICU) stay were recorded.

Results: Fifty two patients could be finally evaluated with MRC; 24 in the EMS group and 28 in the control group. CIPNM was diagnosed in 3 patients in the EMS group as compared to 11 patients in the control group (OR = 0.22; CI: 0.05 to 0.92, P = 0.04). The MRC score was significantly higher in patients of the EMS group as compared to the control group [58 (33 to 60) vs. 52 (2 to 60) respectively, median (range), P = 0.04). The weaning period was statistically significantly shorter in patients of the EMS group vs. the control group [1 (0 to 10) days vs. 3 (0 to 44) days, respectively, median (range), P = 0.003].

Conclusions: This study suggests that daily EMS sessions prevent the development of CIPNM in critically ill patients and also result in shorter duration of weaning. Further studies should evaluate which patients benefit more from EMS and explore the EMS characteristics most appropriate for preventing CIPNM.

Trial registration number: ClinicalTrials.gov NCT00882830.

Figure 1

Schediagram of patients admitted to the ICU and the randomization process. APACHE, Acute Physiology and Chronic Health Evaluation; EMS, electrical muscle stimulation.

Figure 2

Difference in the MRC scale for muscle strength between patients assigned to the EMS group as compared with patients assigned to the control group (mean ± 2 standard errors). P = 0.04. EMS, electrical muscle stimulation; MRC, Medical Research Council.

Figure 3

Kaplan-Meier curves of the probability of remaining under mechanical ventilation after the onset of weaning. (a) Duration of mechanical ventilation (log rank test, P = 0.075). (b) Days off mechanical ventilation (log rank test, P = 0.003). (c) Weaning period (short-term): no need for mechanical ventilation for the next 48 hours (log rank test, P = 0.003). (d) Weaning period (long-term): no need for mechanical ventilation until ICU discharge (log rank test, P = 0.003) for patients in the electrical muscle stimulation (EMS) group as compared with those in the control group.

Figure 4

Kaplan-Meier curves comparing the ICU length of stay in patients with and without critical illness polyneuromyopathy (CIPNM; log-rank test, P = 0.01) and between patients assigned to the electrical muscle stimulation group as compared with patients assigned to the control group (log-rank test, P = 0.11).