Efeitos da estimulação elétrica funcional de quadríceps em pacientes submetidos à cirurgia cardíaca : ensaio clínico randomizado.

Abstract

Surgical stress in heart surgery can lead to loss of muscle mass and strength due to dysregulation in protein metabolism and limitation of exercise capacity. Protein degradation can lead to persistent muscle weakness in the long term. Functional electrical stimulation (FES) is effective in producing maximal recruitment of muscle fibers in patients unable to perform such function. FES has a beneficial systemic effect on the skeletal muscle microcirculation, preserving the synthesis of muscle proteins and becoming effective in the treatment of muscle atrophy for a prolonged period of immobilization in the bed. The type of surgical procedure and the inherent risk of the procedure vary according to the clinical profile and age range of the evaluated patient. In this sense, the present study aimed to evaluate the effects of quadriceps FES on peripheral blood flow, quadriceps muscle thickness and strength, functional capacity and degree of functional mobility of patients in the immediate and late postoperative period of myocardial revascularization, or of valve replacement. The dissertation is expressed in two manuscripts: Summary of the manuscript I: Effects of functional electrical stimulation on peripheral arterial flow, quadriceps thickness and degree of mobility in the postoperative period of cardiac surgery: Randomized clinical trial: FES acts in the prevention of muscle weakness and can be used postoperatively (PO) for CS. However, its effects need to be better understood, so that the objective of this study was to evaluate Ankle-Brachial Index (ABI), quadriceps muscle thickness, and degree of mobility of patients submitted to CS undergoing FES were evaluated. Methods: Randomized single blind clinical trial that assigned to the Control Group (GC), patients undergoing conventional cardiac rehabilitation (CCR) and, in the Intervention Group (IG), those submitted to CCR associated with FES. FES were performed on the rectus femoris and vastus lateralis muscles (20 Hz) for 30 minutes. The ABI, the quadriceps thickness by ultrasound and the degree of functional mobility were evaluated through the Intensive Care Unit Mobility Scale (IMS). Results: Sample (n= 21) (CG: n= 12; GI: n= 9), mean age 61.29 ± 11.64 years and body mass index of 30.82 ± 4.61 kg/m2 (58.3% of males). There was no increase in ABI among the groups (p= 0.393), however, there was intragroup increase in the CG (p= 0.002) and in the IG (p= 0.001). There was no increase in the thickness of the rectus femoris (p= 0.888) and of the vast intermediate (p= 0.999) between the groups nor between the operative moments. However, IG presented greater mobility on the morning of the third day of intensive care unit stay (T5) when compared to GC (p= 0.001). Conclusion: FES increased the functional mobility of patients in the postoperative period of CS without altering peripheral blood flow and quadriceps femoral thickness in the analyzed groups. Summary of the manuscript II: Effects of functional electrical stimulation on quadriceps strength and thickness and gait velocity in the postoperative period of cardiac surgery: Background: The rehabilitation of patients undergoing CS using FES needs to be better understood, so that the objective of this study was to evaluate quadriceps muscle strength and thickness and gait velocity were evaluated in the Six-Meter Velocity Test (6MVT) in this population. Method: Randomized single blind clinical trial evaluating quadriceps muscle strength and thickness and 6MVT performance in patients allocated to the control group (CG) CCR and in the intervention group (IG). The quadriceps muscle strength was evaluated by a load cell coupled to an electromyograph and the muscle thickness was evaluated by ultrasonography. The 6MVT was evaluated in a flat corridor demarcated with 10 meters, being 2 initial meters of acceleration and 2 final meters of deceleration. Results: Sample (n = 21; CG: n = 12; IG: n = 9) aged 61.29 ± 11.64 years (58.3% males). There was no increase in quadriceps muscle strength between groups (p = 0.459), as well as in the intragroup assessment in the CG (p = 0.134) and the IG (p = 0.393). The FES did not alter the thickness of the rectus femoris and the vast intermediate between groups and intragroup. There was a reduction in gait velocity on the 6MVT in the CG (p = 0.001) and in the IG (p = 0.001), and there was no difference between the groups in gait velocity (p= 0.599). Conclusion: Funcional electrical stimulation did not alter the strength, thickness and speed of gait in the postoperative period of cardiac surgery.