TITLE:
Respiratory Mechanics, Respiratory Muscle Strength, Control of Ventilation and Gas Exchange in Patients with Autoimmune Liver Disease
AUTHORS:
Ahmet Baydur, Jacob Korula
KEYWORDS:
Autoimmune Liver Disease, Control of Ventilation, Occlusion Pressure, Passive Relaxation Method, Primary Biliary Cirrhosis, Respiratory Elastance, Respiratory Resistance
JOURNAL NAME:
Open Journal of Respiratory Diseases,
Vol.14 No.2,
March
28,
2024
ABSTRACT: 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 (P0.1) was increased
and negatively associated with FVC; and e) increases in P0.1, mean
inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the
increase in ventilatory drive. Despite inspiratory muscle weakness in patients,
P0.1/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 P0.1 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.