Respiratory Mechanics, Respiratory Muscle Strength, Control of Ventilation and Gas Exchange in Patients with Autoimmune Liver Disease  

作　　者：Ahmet Baydur Jacob Korula Ahmet Baydur;Jacob Korula(Divisions of Pulmonary, Critical Care and Sleep Medicine, Los Angeles, USA;Keck School of Medicine, University of Southern California, Los Angeles, California, USA;Liver Diseases, Rancho Los Amigos National Rehabilitation Center, Downey, California, USA)

机构地区：[1]Divisions of Pulmonary, Critical Care and Sleep Medicine, Los Angeles, USA [2]Keck School of Medicine, University of Southern California, Los Angeles, California, USA [3]Liver Diseases, Rancho Los Amigos National Rehabilitation Center, Downey, California, USA

出　　处：《Open Journal of Respiratory Diseases》2024年第2期25-38,共14页呼吸病期刊（英文）

摘　　要：Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-autoimmune liver disease and control subjects. These findings were then related to control of ventilation and gas exchange. A secondary objective was to assess respiratory muscle strength and gas exchange and their relation to respiratory mechanics. Methods: Measurements included respiratory elastance and resistance using the passive relaxation method. Pulmonary function, gas exchange and control of ventilation were assessed using standard methods. Results: a) Compared to control subjects, Ers in patients with liver disease was on average 50% greater than in controls;b) mean respiratory resistance, expressed as the respiratory constants, K₁ and K₂ in the Rohrer relationship, Pao/V’ = K₁ + K₂V’, was not different from control resistance;c) mean maximal inspiratory and maximal expiratory pressures averaged 36% and 55% of their respective control values;d) inspiratory occlusion pressure in 0.1 sec (P_0.1) was increased and negatively associated with FVC;and e) increases in P_0.1, mean inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the increase in ventilatory drive. Despite inspiratory muscle weakness in patients, P_0.1/Pimax averaged 5-fold higher than in control subjects. Conclusions: Despite inspiratory muscle weakness and a V’_E similar to that in normal subjects, central drive is increased in patients with chronic liver disease. The increase in ventilatory drive is related to smaller lung volumes and weakly associated with increase in respiratory elastance. Findings confirm that P_0.1 is a reliable measure of central drive and is an approach that can be used in the evaluation of control of ventilation in patients with chronic liver disease.Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-autoimmune liver disease and control subjects. These findings were then related to control of ventilation and gas exchange. A secondary objective was to assess respiratory muscle strength and gas exchange and their relation to respiratory mechanics. Methods: Measurements included respiratory elastance and resistance using the passive relaxation method. Pulmonary function, gas exchange and control of ventilation were assessed using standard methods. Results: a) Compared to control subjects, Ers in patients with liver disease was on average 50% greater than in controls;b) mean respiratory resistance, expressed as the respiratory constants, K₁ and K₂ in the Rohrer relationship, Pao/V’ = K₁ + K₂V’, was not different from control resistance;c) mean maximal inspiratory and maximal expiratory pressures averaged 36% and 55% of their respective control values;d) inspiratory occlusion pressure in 0.1 sec (P_0.1) was increased and negatively associated with FVC;and e) increases in P_0.1, mean inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the increase in ventilatory drive. Despite inspiratory muscle weakness in patients, P_0.1/Pimax averaged 5-fold higher than in control subjects. Conclusions: Despite inspiratory muscle weakness and a V’_E similar to that in normal subjects, central drive is increased in patients with chronic liver disease. The increase in ventilatory drive is related to smaller lung volumes and weakly associated with increase in respiratory elastance. Findings confirm that P_0.1 is a reliable measure of central drive and is an approach that can be used in the evaluation of control of ventilation in patients with chronic liver disease.

关 键 词：Autoimmune Liver Disease Control of Ventilation Occlusion Pressure Passive Relaxation Method Primary Biliary Cirrhosis Respiratory Elastance Respiratory Resistance 

分 类 号：R57[医药卫生—消化系统]