[size=20px]A 14-year-old patient undergoes a thoracotomy and laparotomy after a shotgun injury results in severe left lower lobe contusion, large sucking chest wall wound, left diaphragmatic injury, liver injury, and gastric perforation. After damage control laparotomy, and primary closure of his chest wall, his abdomen is packed open. He is receiving continuous sedation, narcotics, and neuromuscular blockade. In this patient, neurally adjusted ventilatory assist (NAVA) would not be effective mode of ventilation because of

 

a chest wall injury

 

b need for continuous sedation

 

c diaphragmatic injury

 

d full neuromuscular paralysis

 

e open abdomen[/size]

D

D

D

D

D

D

Correct answer

d full neuromuscular paralysis

 

Mechanical ventilation in spontaneously breathing children poses many challenges for several reasons. Small tidal volumes, high respiratory rates, high variability in breathing pattern, endotracheal tube leaks necessitated to minimize the development of subglottic stenosis all contribute to unreliable monitoring of respiratory drive and respiratory rate and interfere with patient-ventilator synchrony.

 

Neurally-adjusted ventilatory assist (NAVA) is a method of ventilation that uses the electrical activity of the diaphragm (Edi) to synchronize ventilator support proportionally to the patient’s neural respiratory drive.

 

Since NAVA uses the diaphragm electrical activity as the controller signal, it is possible to deliver synchronized assist, both invasively and non-invasively (NIV-NAVA), to follow the variability in breathing pattern, and to monitor patient respiratory drive, independent of leaks.

 

The use of diaphragm-triggered invasive and non-invasive respiratory support has been used in infants, including preterm newborns, pediatric patients, and adults. It has been described in infants after diaphragmatic hernia repair, after cardiac surgery, and even in patients with Guillain Barre syndrome. However, in patients on full neuromuscular blockade where spontaneous diaphragmatic contraction is not present, NAVA cannot be utilized. An open abdomen, chest wall, or diaphragmatic injury would not preclude use of NAVA. Furthermore, sedation or opioid analgesia also would not preclude NAVA use.