The level of automation in mechanical ventilation has been steadily increasing over the last few decades. There has recently been renewed interest in physiological closed-loop control of ventilation. The development of these systems has followed a similar path to that of manual clinical ventilation, starting with ensuring optimal gas exchange and shifting to the prevention of ventilator-induced lung injury. Systems currently aim to encompass both aspects, and early commercial systems are appearing. These developments remain unknown to many clinicians and, hence, limit their adoption into the clinical environment. This review shows the evolution of the physiological closed-loop control of mechanical ventilation.

Left ventricular assist devices (LVADs) have become a viable alternative to heart transplantation in heart failure therapy. In clinical practice, rotary blood pumps used as LVADs are operated at a constant rotational speed and thus do not adapt to the varying demand of the patient. This paper presents a robust control approach for automatic adaptation of the blood pump speed to the blood flow demand of the patient’s body, which enables a defined load sharing between an LVAD and the native ventricle. Robust stability was checked using a detailed model of the human cardiovascular system with uncertainties that describe the most important native physiological control loops as well as a range of pathologies. The robust assistance controller was tested in an in vivo setup and was able to stabilize the cardiovascular system after myocardial infarction.

Diaphragm atrophy is a common side effect of mechanical ventilation and results in prolonged weaning. Electric phrenic nerve stimulation presents a possibility to avoid diaphragm atrophy by keeping the diaphragm conditioned in sedated patients. There is a need of further investigation on how to set stimulation parameters to achieve sufficient ventilation. A prototype system is presented with a systematic evaluation for stimulation pattern adjustments. The main indicator for efficient stimulation was the tidal volume. The evaluation was performed in two pig models. As a major finding, the results for biphasic pulses were more consistent than for alternating pulses. The tidal volume increased for a range of pulse frequency and pulse width until reaching a plateau at 80–120 Hz and 0.15 ms. Furthermore, the generated tidal volume and the stimulation pulse frequency were significantly correlated (0.42–0.84, $$p<0.001$$ p < 0.001 ). The results show which stimulation parameter combinations generate the highest tidal volume. We established a guideline on how to set stimulation parameters. The guideline is helpful for future clinical applications of phrenic nerve stimulation.

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