Driving Pressure Variation: NAVA vs PSV

Summary

Assisted ventilation represents, nowadays, the preferred ventilation mode in clinical practice.It has been shown that assisted ventilation modes improve ventilation/perfusion matching, descrease risk of Ventilator induced lung injury and muscle atrophy and have less influence on haemodynamic function.

However, PSV (Pressure Support Ventilation) is not free from complications: it may worsen or cause lung injuries by increasing alveolar and intrathoracic negative pressure and by loosing control on Tidal Volume (Vt). Indeed, it has been demonstrated that Vt is the main factor related to VILI.

It has been shown that lower Vt and higher PEEP can improve clinical outcome only if associated with a simultaneous reduction in Driving Pressure. Increase in Driving Pressure resulted strongly associated with negative outcomes, especially if higher than 15 cm H2O.

PSV is currently the most used assisted ventilation mode. NAVA (Neurally Adjusted Ventilatory Assist) is a ventilation mode in which the diaphragmatic electrical activity (EAdi) is used as a trigger to start a mechanical breath, applying positive pressure during patient's inspiration. Diaphragmatic electrical activity (EAdi) can be detected by a particular nasogastric tube (EAdi catheter). EAdi is the currently available signal closest to the neural breathing centers, which can estimate the patient's respiratory drive, if phrenic nerves are not damaged. It has been demonstrated that NAVA ventilation can reduce the incidence of patient-ventilator asynchronies, because the delivery of the support and the cycling between inspiration and expiration are completely controlled by the patient.

However, although PSV and NAVA have been widely compared in many investigations, up to now there are no studies about driving pressure variation during these two modalities of mechanical assisted ventilation. The aim of this study is to measure changes in driving pressure at different levels of ventilatory assistance in PSV and NAVA ventilation modes.

Secondary end points are respiratory mechanics indices and patient/ventilator related asynchrony evaluation and comparison.

Conditions

• Mechanical Ventilation Complication
• Ventilator-Induced Lung Injury

Interventions

DEVICE

NAVAPSV

During the first trial, PSV will be set in order to obtain a Vt between 6 and 8 ml/kg; this support level will be defined as PSV100. Subsequently, the corresponding NAVA level (NAVA 100) will be determined using a dedicated ventilator function (NAVA Preview) which is able to estimate NAVA level in order to deliver an equivalent inspiratory peak pressure (Paw peak) compared to that obtained during PSV mode. Afterwards, PSV100 and NAVA100 will be first increased (PSV150 and NAVA150) during the second trial and then decreased during the third trial (PSV50 and NAVA150) by 50% from basal value. During the study period, PEEP and FiO2 will be kept equal to the values in use before patient enrollment.

Sponsors & Collaborators

• Azienda Ospedaliero Universitaria Maggiore della Carita

  lead OTHER

Principal Investigators

• Gianmaria Cammarota, MD, PhD · AOU Maggiore della Carità

Study Design

Allocation

NA

Purpose

SUPPORTIVE_CARE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2018-11-01

Primary Completion

2019-12-01

Completion

2020-11-01

Countries

• Italy

Study Locations