Parameterization of Respiratory Peripheral Drive in Spontaneously Breathing Patients with Central Drive Depression
Student thesis: Master Thesis and HD Thesis
- Kasper Sørensen
- Esben Bolvig Mark
4. term, Biomedical Engineering and Informatics, Master (Master Programme)
The respiratory drive of the individual patient is of clinical interest to the clinician as this parameter might contribute to an improved treatment. The physiological theories of the mechanisms of respiratory drive is well described. The respiratory control consists mainly of two chemoreflexes that respond to arterial carbon dioxide and oxygen pressure referred to as the central and the peripheral drive control respectively.
Measuring the respiratory drive and determining the contributions of the different drives is not a trivial task. In order to do so a set of mathematical models can be used. Using a sample of arterial blood gas and clinically available parameters for pulmonary gas exchange obtained with the bedside tool ALPE, the respiratory drive of the patient can be parameterized and changes in the patient’s respiration due to change in ventilator settings can be estimated.
The current version of the model of respiratory drive parameterizes the central drive threshold of the patient. The model have not previously been tested on patients with spontaneous breathing and with no mechanical ventilation.
This thesis introduces a novel method for parameterization and es- timation of the peripheral drive of spontaneously breathing patients. The patients included in the selected test group are diagnosed with COPD. This patient group is known to have a reduced central drive. Reduction in central drive poses a threat to the patient, because an increased arterial oxygen pressure may then cause hypoventilation and hypoxemia. Patients submitted to oxygen treatment as in the post-operative period may experience increased arterial oxygen pressure.
Four simple parameter estimation methods are tested in order to estimate the peripheral drive in six spontaneously breathing patients. The methods includes a parameter estimation of different peripheral drive parameters using a grid search algorithm. The four methods of parameter estimation are evaluated both by visually inspection and calculation of mean squared error between measured and estimated alveolar ventilation.
Parameterization of the peripheral drive may be used to describe and predict respiratory response to changes in oxygen treatment at the bedside.
Measuring the respiratory drive and determining the contributions of the different drives is not a trivial task. In order to do so a set of mathematical models can be used. Using a sample of arterial blood gas and clinically available parameters for pulmonary gas exchange obtained with the bedside tool ALPE, the respiratory drive of the patient can be parameterized and changes in the patient’s respiration due to change in ventilator settings can be estimated.
The current version of the model of respiratory drive parameterizes the central drive threshold of the patient. The model have not previously been tested on patients with spontaneous breathing and with no mechanical ventilation.
This thesis introduces a novel method for parameterization and es- timation of the peripheral drive of spontaneously breathing patients. The patients included in the selected test group are diagnosed with COPD. This patient group is known to have a reduced central drive. Reduction in central drive poses a threat to the patient, because an increased arterial oxygen pressure may then cause hypoventilation and hypoxemia. Patients submitted to oxygen treatment as in the post-operative period may experience increased arterial oxygen pressure.
Four simple parameter estimation methods are tested in order to estimate the peripheral drive in six spontaneously breathing patients. The methods includes a parameter estimation of different peripheral drive parameters using a grid search algorithm. The four methods of parameter estimation are evaluated both by visually inspection and calculation of mean squared error between measured and estimated alveolar ventilation.
Parameterization of the peripheral drive may be used to describe and predict respiratory response to changes in oxygen treatment at the bedside.
| Language | English |
|---|---|
| Publication date | 3 Jun 2015 |