Transcutaneous Electrical Diaphragmatic Stimulation (TEDS) for Ventilator Induced Diaphragmatic Dysfunction (VIDD) in critically ill mechanically ventilated patients: A Non-Randomized Interventional Study

Mechanical Ventilation (MV) is one of the most crucial forms of organ support routinely administered in the intensive care unit (ICU), with several studies stating the proportion of patients requiring MV reaching up to 40% (1). Mechanical ventilation is known to have several adverse effects such as ventilator-associated pneumonia (VAP), lung injuries and a recently widely studied issue known as Ventilator-Induced Diaphragmatic Dysfunction (VIDD). VIDD may be defined as reduction in diaphragmatic force-generating capacity specifically related to the use of MV accompanied by diaphragm muscle inactivity and unloading. The prevalence of VIDD in ventilated patients is estimated to be 60-80%, which translates to weaning failure (20%), extended ICU stay and increased mortality (2). VIDD develops within 18-69 hours of Mechanical Ventilation with a loss of over 50% of the cross-sectional area of diaphragmatic muscle fibres (2). VIDD, being a major contributor to weaning failure, necessitates longer ICU and Hospital stays for the patient which translates to increased cost burdens and significant impacts on physical, mental and social morbidity. Even as the entity of VIDD seems inevitable, there are few countermeasures available within the arsenal of the Intensivist to combat it. Lung Protective Ventilation, Ventilator Induced Lung Injury (VILI) mitigation, early inspiratory exercises and Physiotherapy have been the only proven therapy so far to alleviate VIDD. Electrical stimulation of the diaphragm has a strong theoretical concept but resounding evidence for its application is still at large. The idea is that by avoiding the disuse of the diaphragm, its mass and function will be preserved, thereby reducing atrophy and dysfunction. A complete lack of activity in skeletal muscle of the diaphragm leads to atrophy, and it is postulated that only a small amount of exercise (~200 contractions/day) is needed to prevent it (3). Transcutaneous electrical diaphragmatic stimulation (TEDS) is a safe, non-invasive, bedside intervention that can be applied to all critically ill patients with few exceptions. TEDS is reported to increase the number of type II fibres, increase MIP and maximal expiratory pressure (MEP) and decrease the rate of ventilatory weaning failure. TEDS has been successfully integrated, as a part of the physiotherapy protocol, in various countries for a plethora of maladies including Weaning Failure, one of the foremost causes for which is VIDD. Point-of-Care Ultrasonography (POCUS) provides a simple, non-invasive method of quantifying diaphragmatic movement in a variety of normal and pathological conditions. POCUS has been successfully used to diagnose VIDD and several international cut-offs have been postulated which has been explained in detail further down this manuscript (4). There are very few studies done on TEDS in critically ill patients and there’s no available literature pertaining to the Indian population. In our proposed study we aimed to ascertain whether implementation of TEDS in addition to standard of care, in critically ill mechanically ventilated patients with evidence of VIDD, helps in improving Diaphragmatic function as measured by POCUS.

VIDD is a serious entity that causes a significant incidence of weaning failure, morbidity and mortality in critically ill, mechanically ventilated patients. The treatment avenues at the disposal of the intensivist are currently limited and few have proven to be effective in mitigating VIDD. TEDS is a safe, non-invasive, bedside intervention that can be easily applied to all critically ill patients with very few exceptions. Likewise, measuring diaphragmatic function using POCUS is a tried and tested method and its overall safety and repeatability makes it a feasible bedside test for the Intensivist. The overall data on TEDS, while promising, is scarce and so far, only a handful of studies have been conducted on the subject, with no literature to date pertaining to the Indian populace. In our proposed study, we put forward the research question “Among critically ill mechanically ventilated patients with evidence of Ventilator Induced Diaphragmatic Dysfunction (VIDD), admitted to the ICU of a tertiary care Indian hospital, will implementation of Transcutaneous Electrical Diaphragmatic Stimulation (TEDS) in addition to standard care help in improving Diaphragmatic function as measured by Point-of-Care Ultrasonography (POCUS)?”.