Patient-ventilator Interaction During NIV With Helmet: a Comparison Between PSV and the New NIV NPS Software

Non-Invasive Ventilation (NIV) has found many different uses in clinical settings, shortening intubation times and preventing orotracheal intubation. NIV success is highly affected by patient comfort and patient-ventilator synchrony. The helmet is one of the most comfortable interfaces, even if synchrony is low due to dead space. The use of Neurally Adjusted Ventilatory Assist (NAVA), in which the Electrical Activity of the Diaphragm (EAdi) drives the ventilator, has shown improvement in comfort and synchrony but still some limitation with helmet, due to the long pressurization time. Pressure-Support Ventilation (PSV) is still the most used and diffused assisted mode in Europe due to its simplicity and effectiveness in helmet-NIV. The aim of this study is to test a new ventilation software called Neural Pressure Support Ventilation (nPSV), which merges the rapid pressurization of PSV along with the EAdi trigger, onto a population of 24 critical care patients ventilated with a helmet NIV.

Inclusion criteria

• Adult patients (>18aa)
• Non Invasive Ventilation with helmet
• NG tubing for clinical use in position
• Invasive arterial monitoring for clinical use in position

Exclusion criteria

• Unable to express consent
• Expected NIV < 24hrs
• Gastric-esophageal surgery in the preceding 12 months
• Upper-GI bleeding in the last 30 days
• History of esophageal varices
• Recent trauma or facial surgery
• Haemodynamic instability even a after liquid infusion (need of at least dopamine >5 γ/kg/min or norepinephrine >0.1 γ/kg min to obtain systolic pressure >90 mmHg)
• Core temperature >30 C°
• Coagulation disorders (INR > 1.5 and/or aPTT >44 sec)