Ventilator controlled by patient's brain

16 November 2006

Dusseldorf, Germany. Swedish company MAQUET Critical Care has launched its latest ventilator, the SERVO-i ventilator with NAVA (neurally adjusted ventilatory assist) at MEDICA. It has an innovative approach to mechanical ventilation that allows the patient to control the ventilator with their brain's respiratory centre.

The NAVA approach to mechanical ventilation is based on the patient’s neural respiratory output. Signals from respiratory control centre in the brain are transmitted through the phrenic nerve to the diaphragm, where a catheter captures the electrical activity (Edi) and feeds it to the ventilator. The ventilator responds by providing the requested level of support to the patient. As the ventilator and diaphragm work with the same signal, the coupling between the two is virtually instantaneous.

"NAVA is a completely new mode of mechanical ventilation where the ventilator is controlled by the patient’s respiratory centre on a breath-by-breath basis,“ said Christer Sinderby, Assistant Professor, St. Michael’s Hospital, Toronto, Canada. “In addition to being a distinct mode of ventilation, NAVA also enables a complete evaluation of the neural respiratory control by capturing the electrical activity of the diaphragm. In other words, it offers a unique monitoring capability for the medical staff.“

Conventional mechanical ventilators sense patient effort by either a drop in airway pressure or a reversal in flow, the last and slowest reacting step in the chain of respiratory events. NAVA, on the other hand, senses the electrical activity of the diaphragm, which is the earliest respiratory signal that can be detected.

There are several potential benefits with NAVA including:

• Improved synchrony between the patient and the ventilator
• Lung protection through avoidance of over or under assistance of the patient
• Enhanced patient comfort as the improved synchrony helps minimize patient discomfort and agitation while it promotes spontaneous breathing
• The Edi signal can be used as decision support for medical staff concerning unloading or extubation
• The Edi signal can be used as a unique monitoring tool providing information on respiratory drive, volume requirements, effect of ventilatory settings and to gain indication for sedation and weaning

The NAVA function is available on MAQUET Critical Care’s SERVO-i ventilator. The only equipment required in addition to the SERVO-i ventilator is NAVA software, an Edi Module and an Edi catheter. For current SERVO-i users, it will be possible to upgrade an existing SERVO-i with the NAVA function.

“With the technological advancement SERVO-i with NAVA, we firmly demonstrate our dedication to drive innovation within the areas of ventilation therapy and intensive care,“ said Dr. Heribert Ballhaus, vice president, Getinge Medical Systems. “In addition, the breakthrough complements MAQUET’s mission to provide solutions that enable quicker, safer and more cost effective patient care.”

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