Portable mechanical ventilation with closed-loop control of inspired fraction of oxygen maintains oxygenation in the setting of hemorrhage and lung injury

Computer clinical decision support that automates personalized clinical care: a challenging but needed healthcare delivery strategy

How to deliver best care in various clinical settings remains a vexing problem. All pertinent healthcare-related questions have not, cannot, and will not be addressable with costly time- and resource-consuming controlled clinical trials. At present, evidence-based guidelines can address only a small fraction of the types of care that clinicians deliver. Furthermore, underserved areas rarely can access state-of-the-art evidence-based guidelines in real-time, and often lack the wherewithal to implement advanced guidelines. Care providers in such settings frequently do not have sufficient training to undertake advanced guideline implementation. Nevertheless, in advanced modern healthcare delivery environments, use of eActions (validated clinical decision support systems) could help overcome the cognitive limitations of overburdened clinicians. Widespread use of eActions will require surmounting current healthcare technical and cultural barriers and installing clinical evidence/data curation systems. The authors expect that increased numbers of evidence-based guidelines will result from future comparative effectiveness clinical research carried out during routine healthcare delivery within learning healthcare systems.

Swarm optimization approach to design PID controller for artificially ventilated human respiratory system

BACKGROUND AND OBJECTIVE

An artificially ventilated human respiratory system is used to help breathing of a patient with respiratory problem. The level of oxygen is maintained stable by controlling the airway pressure in the lungs mechanism with the help of medical ventilator. For pressure control in a ventilator, the airway pressure in lungs mechanism is controlled by a motor driven piston mechanism. The optimal setting of controller parameters of a respiratory ventilator system depends on many factors of a patient such as physical condition of patient, need of oxygen, age of a patient etc. Therefore, computer operated algorithm based artificial ventilation system becomes most popular for its better performance, efficiency, and easy control mechanism. In this paper, a simple swarm optimization based controller design approach is systematically verified to design suitable controller for pressure controlled artificially ventilated human respiratory system. A modified constricted class topper optimization (C-CTO) algorithm is proposed for tuning the controller in an artificial ventilator system.

METHODS

A pressure controlled ventilation (PCV) model has been considered. A proportional-integral-derivative (PID) controller structure is considered for the PCV. Three different optimization approach (Particle swarm optimization (PSO), class topper optimization (CTO) and a modified constricted class topper optimization (C-CTO)) are verified one by one for the purpose of tuning PID controller for PVC system.

RESULTS

The performances of swarm based controller in PCV system for three different cases are examined in terms of settling times and maximum overshoot of the system.

CONCLUSIONS

The swarm based optimization approach is improving the dynamic response of pressure control artificially ventilated human respiratory system. In this paper, a simple piston-motor driven lung mechanism is applied to verify the swarm based approach, but this approach can further be checked in the future for more complex human lungs artificially ventilated system.

Early Identification of Acute Lung Injury in a Porcine Model of Hemorrhagic Shock

BACKGROUND

Acute lung injury (ALI) is a frequent complication after severe trauma. Lung-protective ventilation strategies and damage control resuscitation have been proposed for the prevention of ALI; however, there are no clinical or laboratory parameters to predict who is at risk of developing ALI after trauma. In the present study, we explored pulmonary inflammatory markers as a potential predictor of ALI using a porcine model of hemorrhagic shock.

MATERIALS AND METHODS

Female swine were randomized to mechanical ventilation with low tidal volume (V_T) (6 mL/kg) or high V_T (12 mL/kg). After equilibration, animals underwent pressure-controlled hemorrhage (mean arterial pressure [MAP] 35 ± 5 mmHg) for 1 h, followed by resuscitation with fresh whole blood or Hextend. They were maintained at MAP of 50 ± 5 mmHg for 3 h in the postresuscitation phase. Bronchoalveolar lavage fluids were collected hourly and analyzed for inflammatory markers. Lung samples were taken, and porcine neutrophil antibody staining was used to evaluate the presence of neutrophils. ELISA evaluated serum porcine surfactant protein D levels. Sham animals were used as negative controls.

RESULTS

Pigs that underwent hemorrhagic shock had higher heart rates, lower cardiac output, lower MAPs, and worse acidosis compared with sham at the early time points (P < 0.05 each). There were no significant differences in central venous pressure or pulmonary capillary wedge pressure between groups. Pulmonary neutrophil infiltration, as defined by neutrophil antibody staining on lung samples, was greater in the shock groups regardless of resuscitation fluid (P < 0.05 each). Bronchoalveolar lavage fluid neutrophil levels were not different between groups. There were no differences in levels of porcine surfactant protein D between groups at any time points, and the levels did not change over time in each respective group.

CONCLUSIONS

Our study demonstrates the reproducibility of a porcine model of hemorrhagic shock that is consistent with physiologic changes in humans in hemorrhagic shock. Pulmonary neutrophil infiltration may serve as an early marker for ALI; however, the practicality of this finding has yet to be determined.

MicroRNA‑146a/Toll‑like receptor 4 signaling protects against severe burn‑induced remote acute lung injury in rats via anti‑inflammation

The present study investigated the preventive effects of microRNA (miR)‑146a against severe burn‑induced remote acute lung injury (ALI) in rats and the underlying mechanism. The surface area of the skin was immersed in 100˚C water for 5‑10 sec on the dorsal surface. The expression level of miR‑146a was significantly downregulated in rats with burn‑induced ALI. Downregulation of miR‑146a increased inflammation, and inducible nitric oxide synthase (iNOS) and cyclooxygenase‑2 (COX‑2) expression in a model of ALI in vitro via the promotion of the Toll‑like receptor (TLR)4/nuclear factor (NF)‑κB signaling pathway. In addition, the overexpression of miR‑146a reduced inflammation, and iNOS and COX‑2 protein expression in the model of ALI in vitro via the suppression of the TLR4/NF‑κB signaling pathway. A TLR4 inhibitor reduced the function of anti‑miR‑146a on inflammation in the model of ALI. Collectively, the results of the present study demonstrated the preventive effects of miR‑146a against severe burn‑induced remote ALI in rats through the anti‑inflammatory‑regulated TLR4/NF‑κB signaling pathway.