Acute Effects of Oxygen Administration on Neuromuscular Fatigue in Chronic Obstructive Pulmonary Disease Patients With Chronic Respiratory Failure and Long-term Oxygen Therapy

Detailed Summary

The literature on the physiological response (vasodilation, neuromuscular fatigue, and muscle oxygenation) following the application of different dosages of oxygen therapy in patients with Chronic Respiratory Failure (CRF) and Long-Term Oxygen Therapy (LTOT) during exercise is scant. The evaluation of these aspects can allow the clinicians and the rehabilitation staff to correctly dose the oxygen therapy at rest and during exercise and to reach a higher level of improvement after training. For this purpose, we will recruit 20 patients admitted to the Pulmonary Unit of the ICS Maugeri in Lumezzane (BS) with the presence of CRF defined as PaO2 at room air less than 60 mmHg, the need for LTOT since 3 months, and with a stable clinical condition. This is a crossover study and will last 3 days. We will test the same subject, randomly, in the following three conditions: A) CONDITION ROOM AIR: patient will breathe room air through the Venturi mask (Vmask FiO2 21%) and will be considered as "sham condition" B) CONDITION FiO2 30%: the subject will breathe through a Venturi mask with a FiO2 of 30%. C) CONDITION FiO2 60%: the subject will breathe through a Venturi mask with a FiO2 of 60%. During each condition, we will evaluate: a) oxygen saturation (SatO2), transcutaneous paCO2 value (tcCO2), BORG fatigue and dyspnea, blood gas analysis; b) mitochondrial function through the Near Infra-Red Spectroscopy and c) vascular function by Single Passive Leg Movement (sPLM) technique; d) central and peripheral neuromuscular fatigue after a submaximal intermittent isometric contraction. The present project will help to understand the best doses of oxygen therapy to allow patients to achieve a higher level of vasodilation and mitochondrial function and a lower level of neuromuscular fatigue. We could apply these results to the rehabilitation program in order to get a greater level of improvement in exercise tolerance.

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