Burkhard Lachmann

Electrical impedance tomography: the holy grail of ventilation and perfusion monitoring?

This review summarizes the state-of-the-art in electrical impedance tomography (EIT) for ventilation and perfusion imaging. EIT is a relatively new technology used to image regional impedance distributions in a cross-sectional area of the body. After the introduction, a brief overview of the recent history is provided followed by a review of the literature on regional ventilation monitoring using EIT. Several recently presented indices that are useful to extract information from EIT image streams are described. Selected experimental and clinical findings are discussed with respect to future routine applications in intensive care. Finally, past and ongoing research activities aimed at obtaining cardiac output and regional perfusion information from EIT image streams are summarized.

Acute respiratory failure complicating advanced liver disease.

Advanced liver disease is associated with hypoxemia and respiratory failure by various mechanisms. Patients with cirrhosis are especially prone to episodes of decompensation requiring intensive care unit admission and management. Such patients may already be in acute liver failure or have decompensated due to a concurrent illness such as spontaneous bacterial peritonitis, sepsis, encephalopathy, varices, or hepatorenal syndrome. Acute respiratory distress syndrome is one of the main reasons for intensive care unit admission and mortality. Overall, critically ill cirrhotic patients frequently progress to multiorgan failure requiring mechanical ventilation. Caring for such patients is therefore understandably complex and extremely challenging. Patients with end-stage liver disease are especially at risk for developing acute respiratory failure and hypoxemia secondary to hepatopulmonary syndrome, portopulmonary hypertension, and hepatic hydrothorax. They should therefore be screened for these conditions because failure to recognize and adequately treat these serious complications of cirrhosis may have devastating consequences. This article is based on a review of the current literature on how to approach and manage acute respiratory failure in advanced liver disease, which is important to intensivists, anesthesiologists, and physicians as a whole.

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

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 4xa0hours 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 10xa0seconds, 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.

Artificial intelligence for closed-loop ventilation therapy with hemodynamic control using the open lung concept

Purpose – The purpose of this paper is to develop an automatic control system for mechanical ventilation therapy based on the open lung concept (OLC) using artificial intelligence. In addition, mean arterial blood pressure (MAP) is stabilized by means of a decoupling controller with automated noradrenaline (NA) dosage to ensure adequate systemic perfusion during ventilation therapy for patients with acute respiratory distress syndrome (ARDS). Design/methodology/approach – The aim is to develop an automatic control system for mechanical ventilation therapy based on the OLC using artificial intelligence. In addition, MAP is stabilized by means of a decoupling controller with automated NA dosage to ensure adequate systemic perfusion during ventilation therapy for patients with ARDS. Findings – This innovative closed-loop mechanical ventilation system leads to a significant improvement in oxygenation, regulates end-tidal carbon dioxide for appropriate gas exchange and stabilizes MAP to guarantee proper system...

A mathematical model for carbon dioxide elimination: an insight for tuning mechanical ventilation

PurposeThe aim is to provide better understanding of carbon dioxide (

Automated respiratory therapy system based on the ARDSNet protocol with systemic perfusion control

mathrm{CO}_2

Automatic artificial ventilation therapy using the ARDSNet protocol enforcing dynamical constraints

CO2) elimination during ventilation for both the healthy and atelectatic condition, derived in a pressure-controlled mode. Therefore, we present a theoretical analysis of