BACKGROUND: The Nocturnal oxygen therapy trial and Medical Research Council studies have shown that home oxygen therapy increases survival and offers hemodynamic benefits to hypoxemic chronic obstructive pulmonary disease. In recent years, research has been aimed at improving patients' quality of life by introducing portable sources of liquid oxygen and oxygen-saving systems, such as the oxymizer and transtracheal catheters. PURPOSE: To identify the acute and long-term hemodynamic response to different methods of oxygen saving devices, oxymizer and transtracheal catheter, in chronic obstructive pulmonary disease patients previously oxygenated via nasal prongs. METHODS: Acute response. A minimum of 3 nocturnal pulse-oximetries were performed with each device (nasal prongs, oxymizer and transtracheal catheter) to find the minimum oxygen flow required to maintain a Sao2 % > 88% during 95% of the night. With the preset oxygen flow, a radionuclide ventriculography was performed at rest and during exercise to calculate the right and left ventricular ejection fraction. Long-term response to transtracheal catheter: Arterial gasometries, hemoglobin determinations, Pulmonary function testing, echocardiography, radionuclide ventriculography (right and left ventricular ejection fractions, and ventricular volumes), right heart catheterization, 6 minute walking test, and a visual analogue scale score were performed at the beginning of the study and 1 year later in 10 hypoxemic chronic obstructive pulmonary disease. RESULTS: Acute response. The increment of the left ventricular ejection fraction during maximal exercise with the oxymizer was significantly lower than with nasal prongs or transtracheal catheter and the right ventricular ejection fraction showed a tendency to decrease (P=0.06). Long-term response to transtracheal catheter. At the end of follow-up, decreases were found in hemoglobin (15.2 to 12.9 g/dL) and forced expiratory volume in the first second (0.78 L to 0.62 L) and the Pao2 (determined with the same oxygen flow via transtracheal catheter) increased (66.8 to 71.0 mm Hg), (P<0.05), but the cardiac work, the 6 minute walking test and the visual analogic scale did not deteriorate. Cardiac index, pulmonary capillary wedge pressure, right and left ventricular ejection fraction did not change. Mean pulmonary arterial pressure did not improve but the pulmonary arteriolar vascular resistances and the right ventricle free wall stress index significantly improved at the end of the study. The end-systolic and end-diastolic volumes of the right ventricle determined at rest showed a tendency to decrease (P=0.06). CONCLUSIONS: For patients on home oxygen therapy, who wish to maintain maximal physical activity, the oxymizer is not recommended as an oxygen saving device. Long-term oxygenation, 24 hours per day with liquid oxygen via transtracheal catheter in hypoxemic patients previously on home oxygen therapy with nasal prongs, who maintained physical activity showed improved oxygenation (hemoglobin values decreased), improved Pao2. and showed hemodynamic benefits (decrease of the post-load). All these results occurred despite the forced expiratory volume in the first second deterioration, maintaining the same degree of dyspnea (unchanged visual analogue scale score) and exercise capacity (no changes in 6 minute walking test).
|Journal||Journal of Applied Research|
|Publication status||Published - 3 Nov 2004|
- Isotopic ventriculography
- Nasal prongs
- Right heart catheterization
- Right ventricle free wall stress
- Transtracheal catheter