Regulation Of Mean Arterial Pressure Research Articles

Fractional-order PID controller for blood pressure regulation using genetic algorithm

In this paper, fractional order PID controller [FOPID] is designed for automatic blood pressure regulation. One of the most common problems faced by post-operative patients is abnormal blood pressure (BP). Infusion of sodium nitroprusside (SNP) into the patient reduces blood pressure by relaxing the peripheral vasculature's muscles. The patient’s BP must be continuously monitored by an expert and the correct dose has to be given to the patient. It will be difficult to give the desired dosage to a patient manually because drug sensitivity is different for different patients. So, an appropriate controller must be designed to regulate blood pressure and minimize clinical expenses. A fractional-order PID controller is proposed in this paper to regulate mean arterial pressure, and FOPID parameters are optimized as a function of minimizing integral absolute error (IAE), integral squared error (ISE), and integral time absolute error (ITAE) using genetic algorithm. The performance of the proposed system is improved in terms of undershoot, settling time, and maximum peak overshoot. A MATLAB environment was used for the simulation of the system and the implementation of the algorithm.

Sex difference in the activation of central autonomic control regions in chronic intermittent hypoxia

Obstructive sleep apnea (OSA) results in sustained daytime hypertension. Chronic intermittent hypoxia (CIH) mimics the repetitive bouts of arterial hypoxemia associated with OSA. Male Sprague Dawley rats treated with CIH develop sustained hypertension and increased activation of central autonomic regions that regulate mean arterial pressure (MAP). However, gonadally intact female rats exposed to modest CIH treatment are not hypertensive. In male rats, lesions of the median preoptic nucleus (MnPO) prevent CIH-induced increase of MAP. We hypothesize that activation of MnPO and other autonomic control regions may contribute to the sex differences in the MAP response to CIH. To test this hypothesis, adult gonadally intact male and female rats (250-300 g bw) were exposed to either continuously normoxic (CON) or treated with CIH (10% O2 every 3 mins alternating with 21% O2 every 3 mins, 8 h/day) for 7 days. One week before the experiment started, some rats were instrumented with radiotelemetry transmitters to measure MAP and heart rate (HR). After one week of baseline recording, the rats were exposed to either normoxia or CIH and were euthanized (inactin 100 mg/kg ip) on the 8th day for immunohistochemistry. Forebrain and brainstem sections were stained for FosB/ΔFosB. Forebrain sections were also stained for neuronal nitric oxide synthase (NOS1) while brainstem sections were processed for dopamine-β-hydroxylase (DBH). The numbers of cells positive for NOS1 and FosB neurons in MnPO were counted and DBH and FosB positive neurons were counted in the hindbrain autonomic regions. CIH was associated with increased FosB staining in males but not females. Male exhibited an increase in the average number of FosB positive neurons (CON male 20 ± 2 cells/section, CIH male 35 ± 3; CON female 11 ± 1, CIH female 12 ± 2,) and colocalization of FosB and NOS1 (CON male 10 ± 1 cells/section, CIH male 18 ± 4; CON female 5 ± 1, CIH female 6 ± 1) in the MnPO. CIH females (n = 3) did not demonstrate increases in the numbers of FosB positive cells or DBH positive neurons in the commissural nucleus tractus solitarius (CON 7 ± 2, CIH 8 ± 2), rostral ventrolateral medulla (CON 2 ± 1, CIH 3 ± 1), caudal ventrolateral medulla (CON 5 ± 1, CIH 6 ± 2), and area postrema (CON 2 ± 1, CIH 2 ± 1) compared to CON females (n = 2). These preliminary results suggests that CIH is associated with increased FosB staining in the autonomic regions of male rats as opposed to female rats which is consistent with our working hypothesis. In addition, CIH was associated with increased FosB staining in NOS1 positive MnPO neurons suggesting that they may play a role in the sustained hypertension reported in male rats. The research is funded by NIH grant RO1 HL155977 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A multiscale model of the cardiovascular system that regulates arterial pressure viaclosed loopbaroreflex control of chronotropism, cell-level contractility, and vascular tone.

Multiscale models of the cardiovascular system can provide new insights into physiological and pathological processes. PyMyoVent is a computer model that bridges from molecular- to organ-level function and which simulates a left ventricle pumping blood through the systemic circulation. Initial work with PyMyoVent focused on the end-systolic pressure volume relationship and ranked potential therapeutic strategies by their impact on contractility. This manuscript extends the PyMyoVent framework by adding closed-loop feedback control of arterial pressure. The control algorithm mimics important features of the physiological baroreflex and was developed as part of a long-term program that focuses on growth and biological remodeling. Inspired by the underlying biology, the reflex algorithm uses an afferent signal derived from arterial pressure to drive a kinetic model that mimics the net result of neural processing in the medulla and cell-level responses to autonomic drive. The kinetic model outputs control signals that are constrained between limits that represent maximum parasympathetic and maximum sympathetic drive and which modulate heart rate, intracellular Ca2+ dynamics, the molecular-level function of both the thick and the thin myofilaments, and vascular tone. Simulations show that the algorithm can regulate mean arterial pressure at user-defined setpoints as well as maintaining arterial pressure when challenged by changes in blood volume and/or valve resistance. The reflex also regulates arterial pressure when cell-level contractility is modulated to mimic the idealized impact of myotropes. These capabilities will be important for future work that uses computer modeling to investigate clinical conditions and treatments.

Adaptive optimal target controlled infusion algorithm to prevent hypotension associated with labor epidural: An adaptive dynamic programming approach

Patients receiving labor epidurals commonly experience arterial hypotension as a complication of neuraxial block. The purpose of this study was to design an adaptive optimal controller for an infusion system to regulate mean arterial pressure. A state–space model relating mean arterial pressure to Norepinephrine (NE) infusion rate was derived for controller design. A data-driven adaptive optimal control algorithm was developed based on adaptive dynamic programming (ADP). The stability and disturbance rejection ability of the closed-loop system were tested via a simulation model calibrated using available clinical data. Simulation results indicated that the settling time was six minutes and the system showed effective disturbance rejection. The results also demonstrate that the adaptive optimal control algorithm would achieve individualized control of mean arterial pressure in pregnant patients with no prior knowledge of patient parameters.

Mean arterial pressure control system using model predictive control and particle swarm optimization

Linear controllers have been designed to regulate mean arterial pressure (MAP) in treating various cardiovascular diseases. For patients with hemodynamic fluctuations, the MAP control system must be able to provide more sensitive control. Therefore, in this paper, a model predictive control (MPC) approach is presented to improve the sensitivity of MAP control system. The MPC principle can effectively handle the dead times in nonlinear systems, and can also optimize the system responses when subjected to constraints of process states and control signals. Besides, particle swarm optimization (PSO) is employed to solve the optimization problem of MPC at each control interval. According to our simulations, the MAP control system with combined MPC–PSO approach is superior in control qualities to the MAP control system with conventional linear control method. The MPC–PSO MAP control system is possible to be realized through a field-programmable gate array.

Multiple-model adaptive predictive control of mean arterial pressure and cardiac output.

A multiple-model adaptive predictive controller has been designed to simultaneously regulate mean arterial pressure and cardiac output in congestive heart failure subjects by adjusting the infusion rates of nitroprusside and dopamine. The algorithm is based on the multiple-model adaptive controller and utilizes model predictive controllers to provide reliable control in each model subspace. A total of 36 linear small-signal models were needed to span the entire space of anticipated responses. To reduce computation time, only the six models with the highest probabilities were used in the control calculations. The controller was evaluated on laboratory animals that were either surgically or pharmacologically altered to exhibit symptoms of congestive heart failure. During trials, the controller performance was robust with respect to excessive switching between models and nonconvergence to a single dominant model. A comparison is also made with a previous multiple-drug controller design.