Automatic protective ventilation using the ARDSNet protocol with the additional monitoring of electrical impedance tomography

Abstract

IntroductionAutomatic ventilation for patients with respiratory failure aims at reducing mortality and can minimize the workload of clinical staff, offer standardized continuous care, and ultimately save the overall cost of therapy. We therefore developed a prototype for closed-loop ventilation using acute respiratory distress syndrome network (ARDSNet) protocol, called autoARDSNet.MethodsA protocol-driven ventilation using goal-oriented structural programming was implemented and used for 4 hours in seven pigs with lavage-induced acute respiratory distress syndrome (ARDS). Oxygenation, plateau pressure and pH goals were controlled during the automatic ventilation therapy using autoARDSNet. Monitoring included standard respiratory, arterial blood gas analysis and electrical impedance tomography (EIT) images. After 2-hour automatic ventilation, a disconnection of the animal from the ventilator was carried out for 10 seconds, simulating a frequent clinical scenario for routine clinical care or intra-hospital transport.ResultsThis pilot study of seven pigs showed stable and robust response for oxygenation, plateau pressure and pH value using the automated system. A 10-second disconnection at the patient-ventilator interface caused impaired oxygenation and severe acidosis. However, the automated protocol-driven ventilation was able to solve these problems. Additionally, regional ventilation was monitored by EIT for the evaluation of ventilation in real-time at bedside with one prominent case of pneumothorax.ConclusionsWe implemented an automatic ventilation therapy using ARDSNet protocol with seven pigs. All positive outcomes were obtained by the closed-loop ventilation therapy, which can offer a continuous standard protocol-driven algorithm to ARDS subjects.

Optimizing PEEP by Electrical Impedance Tomography in a Porcine Animal Model of ARDS

“…However, up until now, no study exists in either patients or animals that shows the benefits of regulating ventilation parameters by EIT in terms of clinical outcome parameters. 29,34 Recently, different EIT parameters were introduced to find the best PEEP for optimizing ventilator therapy, some of them concerned with establishing homogeneity. Blankman et al 35 optimized PEEP settings during a decremental PEEP trial in 12 post-cardiac surgery subjects by using the intratidal gas distribution index as a new homogeneity parameter, calculated by EIT.…”

Electrical impedance tomography as possible guidance for individual positioning of patients with multiple lung injury

“…This study shows that EIT has the potential to visualize gravity‐dependent changes during ventilation, both in healthy lungs during spontaneous breathing and in case of multiple lung injury during mechanical ventilation. So far, some studies (mainly PEEP trials) have examined ventilator settings monitored by EIT . It was shown that intratidal gas distribution, detected by EIT, has the potential to estimate the extent of overdistension and lung recruitment during PEEP trials .…”

Personalizing mechanical ventilation according to physiologic parameters to stabilize alveoli and minimize ventilator induced lung injury (VILI)

“…Optimization of the protective mechanical breath could be achieved if a closed-loop feedback system existed, in which the physician analyzes changes in lung physiology and uses this as feedback to adjust ventilator settings, with the goal to maintain an open and stable lung regardless of the degree of lung pathology (Fig. 1 ) [ 10 , 11 ]. Since both alveolar opening and collapse time constants vary depending on lung injury severity and evolve as the lung pathology improves or deteriorates, ventilator settings must be constantly adjusted to fit the specific needs of the individual [ 12 – 19 ].…”