Effects of TENS and IES on the Autonomous Balance of Normotens Volunteers and Hypertensive Patients
Condition: Healthy Volunteers; Hypertension, Essential
MeSH terms: Essential Hypertension
Study type: Interventional

Summary: 
      Hypertension is considered a serious public health problem. The imbalance in autonomic
      nervous system (ANS) activity is one of the main triggers in the development and maintenance
      of hypertension. The non-pharmacological management of this disease is an important resource,
      especially in refractory hypertensive patients or in hypertensive crises, where the
      pharmacological treatment does not present an efficient response. It is known that
      transcutaneous electrical nerve stimulation (TENS) is capable of modifying the autonomic
      balance, however, the effects of Interferential electrical stimulation (IES) on this system
      in normotensive and hypertensive volunteers are not yet known. These electrotherapeutic
      resources may be a non-pharmacological tool supporting the management of hypertension. The
      objective of this research is to study the effects of different TENS and IC parameters on
      cardiovascular variables of normotensive volunteers and hypertensive patients.
    

Detailed description: 
      Each volunteer will perform three assessments with a one-week interval. Each assessment will
      include assessment of autonomic balance, blood pressure, and blood collection
      (catecholamines). Interventions (placebo, low frequency TENS and IES) will be randomized.
      Volunteers will be accommodated in the supine position. With properly sanitized skin (70%
      alcohol) and self-adhesive electrodes (5x5 area) will be positioned in the cervical
      paravertebral region. All participants will be submitted to a placebo TENS session, a low
      frequency TENS session (TENS, 10 Hz/200μs) and an IES session (STEIN et al., 2012). The
      sessions will take place in the morning in a 12-hour fast, lasting 30 minutes, in an
      air-conditioned place (23ºC).
    

Intervention name(s): Transcutaneous nervous electric stimulation (TENS); Interferential electrical stimulation (IES); TENS and IES Placebo
Intervention type(s): Device; Device; Device
Intervention description(s): TENS (Frequency 10 Hz or 100Hz /duration 200μs, Endophasys nms 0501® model, KLD Biosystems, Amparo, SP, Brazil) will be applied with intensity between 1 to 60 mA and the current will be adjusted every 5 minutes at the sensory threshold level muscle contraction or according to the tolerance to the stimulus informed by the volunteers. TENS will be applied in bilateral paravertebral region of C7 to T4 or long the brachial plexus and sciatic plexus.; The IES (Endophasys nms 0501®, KLD Biosystems, Amparo, SP, Brazil) will be applied in continuous mode with biphasic pulses. Bipolar electrodes with slope of 1/5/1. The rest of the parameters will be set to 4000 Hz, AMF of 100 Hz and the AMF variation of 25 Hz. The effect of the current will be adjusted by the intensity, it should produce paresthesia stimuli, without pain and below the motor threshold. Adhesive electrodes (MultiStick®, Axelgaard Manufacturing CO, Ltd, Fallbrook, CA, USA) will be housed in the paravertebral region, between C7 (Channel 1) and T4 (Channel 2). (SANTOS et al., 2013); Same protocol without electrical output.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment