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Correspondence

Indian Pediatr 2015;52: 444

Guaranteeing the Volume Guarantee Ventilation


Abdul Razak

Consultant in Neonatal Medicine, Motherhood hospital Bangalore, Karnataka, India.
Email: razakmdpaed@gmail.com 

     


Atelecto-trauma resulting from varying tidal volumes is the key factor resulting in ventilation associated lung injury and thereby causing chronic lung disease [1]. The Volume guarantee ventilation (Babylog), a form of volume targeted ventilation, has been documented to reduce chronic lung disease [2]. However, there is a caution while using this form of ventilation.

Volume guarantee ventilation is a time-cycled pressure – limited volume –targeted ventilation. The edge of Volume guarantee over other forms of ventilation is ensuring the target tidal volume, and auto weaning. The problem arises in this mode if the neonate has severe metabolic acidosis. The neonate is vigorous and has high spontaneous breath rates, due to acidosis, overshooting the back-up rates. As a result, the tidal volumes during these spontaneous breaths are higher or equal to the set tidal volume, and the working peak inspiratory pressure (PIP) is closer to the positive end expiratory pressure (PEEP) making the mode as ventilator continuous positive airway pressure (CPAP). The general condition would not allow to extubate to CPAP and the blood gases are also acceptable making it more difficult to raise the tidal volumes. We try to overcome this situation by switching off to synchronized intermittent mandatory ventilation (SIMV) mode keeping a difference between PIP and PEEP so that the delta P is maintained.

Allowing ventilator to auto-wean could lead to problems, if the flow sensor is blocked or is disturbed, resulting in higher tidal volume, VALI and inadvertent hypocarbia; hence, the flow sensor needs to be in efficient working condition. Auto-triggering owing to high leak may also result in hypocarbia.

Although, the Babylog recommends coupling the Volume guarantee with SIMV, Synchronized intermittent positive pressure ventilation (SIPPV) or Patient support ventilation (PSV); Volume guarantee should not be coupled with SIMV as the unsupported breaths would have varying tidal volumes, and could result in atelectotrauma.

Volume guarantee mode is a robotic mode which operates automatically rendering us interfering least, except for fraction inspired oxygen. The modality needs efficient understanding by the operator, and if used cautiously is a state-of-art. However, it could be double edged sword if the issues mentioned above are not looked into carefully, especially in a busy unit.

References

1. Keszler M. Volume-targeted Ventilation. Neo Reviews. 2006;7:e250 -7.

2. Ethawi YAI. Volume-targeted versus pressure-limited ventilation for preterm infants: A systematic review and meta-analysis. J Clin Neonatol. 2012;1:18-20.

 

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