Health care professionals may be asked about lowvoltage electronic devices now being used to diagnose and/or treat a number of health problems. Most are galvanometers that measure skin resistance to an electric current. The FDA classifies "devices that use resistance measurements to diagnose and treat various diseases" as Class III devices that require FDA approval prior to marketing. None of the devices reviewed here has such approval.

The FDA has approved the use of a responsive neurostimulator device (RNS System – NeuroPace) for adjunctive treatment of adults with partial-onset seizures that are not controlled with ≥2 antiepileptic drugs and who have frequent and disabling seizures and no more than 2 epileptogenic foci.

The FDA has approved the Obalon Balloon System (Obalon), a swallowable intragastric gas-filled balloon device, to facilitate weight loss in adults with a body mass index (BMI) of 30-40 kg/m² who have not been able to lose weight through diet and exercise. Two other gastric balloon devices, ReShape and Orbera, were approved earlier.

The FDA has approved the Minimed 670G (Medtronic), a hybrid closed-loop insulin delivery system for use in patients ≥14 years old with type 1 diabetes. The system uses an algorithm to automatically adjust basal insulin doses based on readings from a continuous glucose monitor (CGM). It fully automates basal insulin delivery in "auto" mode, but is considered a "hybrid" system (not a true "artificial pancreas") because it requires some action by the patient. The 670G system is expected to become available in Spring 2017.

The FDA has approved AspireAssist (Aspire Bariatrics), a weight-loss device that permits patients to drain a portion of their stomach contents through a gastrostomy tube into a toilet after each meal. It is approved for long-term use in combination with lifestyle modifications in adults ≥22 years old who have a body mass index (BMI) of 35 to 55 and have not been able to achieve and maintain weight loss with nonsurgical therapy.

The FDA has approved the use of a transcatheter mitral valve device (MitraClip – Abbott) for percutaneous treatment of significant symptomatic degenerative mitral regurgitation (grade 3-4+) in patients who are at prohibitive risk for mitral valve surgery. It is the first percutaneous nonsurgical treatment approved for this indication.

Implanted devices that monitor cardiac rhythm and can recognize and treat ventricular tachycardia or ventricular fibrillation are now widely used in the USA and other countries. Implantable cardioverter/defibrillators (ICDs) marketed here include the Ventak P and PRX (Cardiac Pacemakers, Inc., St. Paul, MN), the PCD (Medtronic, Minneapolis, MN), and the Cadence (Ventritex, Sunnyvale, CA) (JG Porterfield et al, Am J Cardiol, 72:301, 1993).

The FDA recently expanded the eligibility criteria (see Table 1) for treatment with the surgically implanted hypoglossal nerve stimulation system (Inspire Upper Airway Stimulation – Inspire Medical Systems). The device has been advertised lately on radio and television.

The intramedullary venous plexus of cancellous bone marrow does not collapse in patients who are dehydrated or in shock. Intraosseous (IO) infusion through an intramedullary cannula has effectively replaced central venous catheterization (CVC) as the method of choice for rapid vascular access in both adults and children when peripheral veins are inaccessible. Absorption of fluids into the central circulation with IO infusion is equivalent to absorption from IV sites, and IO access can be achieved more rapidly and with a higher success rate than CVC.

A device that stimulates the vagus nerve was approved by the FDA in July 1997 for treatment of refractory epilepsy and is now considered "approvable" for treatment-resistant depression.