Regulation of hypnosis in Propofol anesthesia administration based on non-linear control strategy / Controle da hipnose na administração de propofol com base na estratégia de controle não linear

Abstract Continuous adjustment of Propofol in manual delivery of anesthesia for conducting a surgical procedure overburdens the workload of an anesthetist who is working in a multi-tasking scenario. Going beyond manual administration and Target Controlled Infusion, closed-loop control of Propofol infusion has the potential to offer several benefits in terms of handling perturbations and reducing the effect of inter-patient variability. This paper proposes a closed-loop automated drug administration approach to control Depth Of Hypnosis in anesthesia. In contrast with most of the existing research on anesthesia control which makes use of linear control strategies or their improved variants, the novelty of the present research lies in applying robust control strategy i.e. Sliding Mode Control to accurately control drug infusion. Based on the derived patient's model, the designed controller uses measurements from EEG to regulate DOH on Bispectral Index by controlling infusion rate of Propofol. The performance of the controller is investigated and characterized with real dataset of 8 patients undergoing surgery. Results of this in silico study indicate that for all the patients, with 0% overshoot observed, the steady state error lies in between ±5. Clinically, this implies that in all the cases, without any overdose, the controller maintains the desired DOH level for smooth conduction of surgical procedures.

Resumo O ajuste contínuo de propofol na administração manual de anestesia para um procedimento cirúrgico onera a carga de trabalho de anestesistas que trabalham em ambiente multitarefa. Indo além da administração manual e da infusão alvo-controlada (IAC), o controle de circuito fechado da infusão de propofol tem o potencial de oferecer vários benefícios em termos de manejo das perturbações e reduzir o efeito da variabilidade interpaciente. Este artigo propõe uma abordagem para a administração automatizada de drogas em circuito fechado para controlar a profundidade da hipnose (PDH) em anestesia. Em contraste com a maioria das pesquisas existentes sobre o controle da anestesia que usam estratégias de controle linear ou de suas variantes melhoradas, a novidade da presente pesquisa reside na aplicação de uma estratégia de controle consistente; isto é, o Controle por Modos Deslizantes (CMD) para controlar com precisão a infusão da droga. Com base no modelo derivado do paciente, o controlador projetado usa as medições do EEG para regular a PDH no Bispectral Index (BIS), controla a taxa de infusão de propofol. O desempenho do controlador é investigado e caracterizado com um conjunto de dados reais de oito pacientes submetidos à cirurgia. Os resultados deste estudo in silico indicam que, para todos os pacientes, com 0% de excesso observado, o erro de estado estacionário fica entre ± 5. Clinicamente, isso implica que em todos os casos, sem qualquer sobredosagem, o controlador mantém o nível desejado de PDH para a condução tranquila dos procedimentos cirúrgicos.

Application of Propfol Closed-loop Anesthesia System in Pediatric Otorhinolaryngologic Surgery / 中国医科大学学报

Objective To evaluate the application of propfol?remifentanil closed?loop and opened?loop anesthesia in children otorhinolaryngologic operation under BIS monitoring. Methods Fourty children underwent elective children tonsillectomy and adenoidectomy were recruited for the study and randomly divided into two groups:closed?loop group(group T)and opened?loop group(group C),with 20 children each. The two groups all received total intravenous induction,then the subjects of closed?loop group were administrated with a method of system automatic regulation of plasma target control and the opened?group cases underwent manual adjustment of plasma target control method according to the BIS value during op?eration. The variables of non?invasive blood pressure(BP),heart rate(HR),pulse oxygen saturation(SpO2),electrocardiogram(ECG),bispec?tral index(BIS),the number of times the manual adjustment of propfol target control applied,and recovery time,were recorded respectively at the time points of before anesthesia(T0),immediately after intubation(T1),5 min after intubation(T2),10 min after(T3),15 min after(T4),30 min after(T5)and the removal of endotracheal intubation(T6). Results The total dosage of propfol in group T was less than the dosage in group C with dosage decrease of 9.83%;there was no significant statistical difference of the total dosage of remifentanil. Conclusion The use of propfol?remi?fentanil closed?loop anesthesia in children otorhinolaryngologic operation is safe,easy,and of strong controllability,which should be widely promoted.