Respiratory airflow patterns that satisfy power and force criteria of optimality

Ruttimann, Urs E.; Yamamoto, William S.

doi:10.1007/bf02584204

Cited by 23 publications

(7 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although in this model, two equation sets were proposed to quantify the mechanical cost, RSM2 was discarded in [9] because it always led to an impulsive inspiratory pressure profile with an extremely small inspiratory duty cycle; this behavior had been also noted by other researchers [83,75]. However, in this study with the used optimization techniques was possible to adjust the model parameters in order to obtain a response with a realistic behavior (see Fig.…”

Section: Optimization Problemmentioning

confidence: 76%

Novel Modeling of Work of Breathing for Its Optimization During Increased Respiratory Efforts

Higuita

Mañanas

Sánchez

et al. 2016

IEEE Systems Journal

View full text Add to dashboard Cite

One of the most complex physiological systems whose modeling is still an open study is the respiratory control system where different models have been proposed based on the criterion of minimizing the work of breathing (WOB). The aim of this study is twofold: to compare two known models of the respiratory control system which set the breathing pattern based on quantifying the respiratory work; and to assess the influence of using direct-search or evolutionary optimization algorithms on adjustment of model parameters. This study was carried out using experimental data from a group of healthy volunteers under CO 2 incremental inhalation, which were used to adjust the model parameters and to evaluate how much the equations of WOB follow a real breathing pattern. This breathing pattern was characterized by the following variables: tidal volume, inspiratory and expiratory time duration and total minute ventilation. Different optimization algorithms were considered to determine the most appropriate model from physiological viewpoint. Algorithms were used for a double optimization: firstly, to minimize the WOB and secondly to adjust model parameters. The performance of optimization algorithms was also evaluated in terms of convergence rate, solution accuracy and precision. Results showed strong differences in the performance of opti- mization algorithms according to constraints and topological features of the function to be optimized. In breathing pattern optimization, the sequential quadratic programming technique (SQP) showed the best performance and convergence speed when respiratory work was low. In addition, SQP allowed to implement multiple non-linear constraints through mathematical expressions in the easiest way. Regarding parameter adjustment of the model to experimental data, the evolutionary strategy with covariance matrix and adaptation (CMA-ES) provided the best quality solutions with fast convergence and the best accuracy and precision in both models. CMAES reached the best adjustment because of its good performance on noise and multi-peaked fitness functions. Although one of the studied models has been much more commonly used to simulate respiratory response to CO 2 inhalation, results showed that an alternative model has a more appropriate cost function to minimize WOB from a physiological viewpoint according to experimental data.

show abstract

Section: Optimization Problemmentioning

confidence: 76%

Novel Modeling of Work of Breathing for Its Optimization During Increased Respiratory Efforts

Higuita

Mañanas

Sánchez

et al. 2016

IEEE Systems Journal

View full text Add to dashboard Cite

show abstract

“…The rectangular pattern was chosen since it has been suggested in the literature (Ruttiman and Yamamoto 1972) to be the optimal airflow pattern in exercise. However, according to earlier experimental observations reported in the literature, the airflow pattern was found to be widely different and posture dependent in different individuals (Morrow and Vosteen 1953;Proctor and Hardy 1949).…”

Section: Discussionmentioning

confidence: 99%

“…Another hypothesis based on minimization of average force of the respiratory muscles was proposed by Mead (1960) for the same purpose. Later it was shown by Ruttiman and Yamamoto (1972) that the human airflow pattern during exercise can be better explained by the minimum work rate criterion. Yamashiro and Grodins (1973) used the minimum work rate hypothesis to optimize the respiratory frequency.…”

Section: Introductionmentioning

confidence: 98%

“…Rectangular and sinusoidal airflow patterns are both used at a wide range of ventilation and activity. The rectangular pattern is chosen because it has been suggested to be the optimal airflow pattern in exercise (Ruttiman and Yamamoto 1972). The sinusoidal airflow pattern is used to represent the main harmonic of any nonspecific airflow shape in exercise.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Function of brainstem neurons in optimal control of respiratory mechanics

Tehrani

2003

Biological Cybernetics

View full text Add to dashboard Cite

An optimization control procedure is developed to describe the function of the human respiratory controller in determination of the respiratory frequency, the expiratory reserve volume, and the physiological dead space volume at all levels of human activity. The required level of alveolar ventilation is considered to have been determined based on the inputs from the peripheral and central chemoreceptors. The proposed procedure describes the mechanical control of breathing in which the excitation signals are adjusted and transferred from the neuron pools in the brainstem to the respiratory muscles to control the rate and depth of breathing. The criterion of minimum average respiratory work rate is used to find the optimal characteristics of respiration. The respiratory frequency, physiologic dead space volume, and expiratory reserve volume are used simultaneously as the optimization variables to minimize the average respiratory work rate. The optimization procedure has been applied by using different airflow patterns at various levels of ventilation. The theoretical results of the study have been compared with the experimental data in exercise taken from the literature. The results show a close agreement between the experimentally measured data and the theoretical values found by the optimization control procedure. The findings attest to the validity of the minimum average work rate criterion and the proposed multivariable optimization procedure compared with other procedures suggested in the literature in control of respiratory mechanics.

show abstract

“…Predictions of the volume-time trajectory based on an optimization criterion have also been made by Ruttiman and Yamamoto [5] and Hamalainen and Viljanen [6].…”

Section: Introductionmentioning

confidence: 99%

Automated solutions of breathing pattern optimizations

Yamashiro

Taylor

Luk

et al. 1994

Computers & Mathematics with Applications

View full text Add to dashboard Cite

A numerical procedure which allows the convenient exploration of various optimize, tion hypotheses of breathing pattern regulation is described. The method is based on the calculus of variations and uses a novel technique for the automatic evaluation of all required derivatives. Advantages of this approach include: exact calculation of all derivatives, parsimonious computer code, and speed of execution. By eliminating the need for hand calculation of derivatives, a major reduction was made in the tedium involved in exploring various optimization strategies. Examples are presented of determining the optimal breathing pattern characteristics for minimum work or force (pressure) required for breathing, based on linear and nonlinear models of respiratory mechanics. The developed procedure can be used to predict the optimal volume-time trajectory and breathing frequency which minimizes a criterion function subject to constraints.

show abstract

Respiratory airflow patterns that satisfy power and force criteria of optimality

Cited by 23 publications

References 10 publications

Novel Modeling of Work of Breathing for Its Optimization During Increased Respiratory Efforts

Novel Modeling of Work of Breathing for Its Optimization During Increased Respiratory Efforts

Function of brainstem neurons in optimal control of respiratory mechanics

Automated solutions of breathing pattern optimizations

Contact Info

Product

Resources

About