Addition of Nitric Oxide to Oxygen Improves Cardiopulmonary Function in Patients With Severe COPD: Results
Mean values of hemodynamic variables are shown in Table 2. Inhaled NO did not significantly alter the systemic circulatory indexes HR, MAP, pulmonary capillary wedge pressure, or SVRI at any level of NO concentration. However, Cl, which remained unchanged with 5 ppm NO, did increase by 9% at 10 ppm and by 12% at 20 ppm NO. There were significant changes in the pulmonary circulation. Addition of 5 ppm and 10 ppm NO to LTOT decreased MPAP by 14% and 17%, respectively, compared with control (p<0.05). No further improvement was observed at 20 ppm NO. At the same time, PVRI decreased by 19% and 26%, respectively (p<0.05). Calculated REF improved by 9% at 5 ppm and by up to 12% at 10 ppm NO.
The effect of the addition of NO to oxygen on gas exchange is given in Table 3. Both arterial oxygenation and the Pa02/FIo2 ratio were significantly improved by the application of NO. There was a ceiling effect on the Pa02, which increased by 26% of control at 5 ppm NO, but no further at higher concentrations. The Pa02/FIo2 ratio improved by 24% of control at all NO concentrations. The Qs/Qt decreased to a minimum value of 17% at 20 ppm NO. The N02 concentration measured by the chemoluminescence detection analyzer was always <1 ppm. Methemoglobin concentration was 0.37±0.17% at control, and 0.37±0.13% at 5 ppm, 0.38±0.15% at 10 ppm, and 0.42±0.16% at 20 ppm NO, demonstrating no significant increase during the duration of the study.
Individual responses with respect to PVRI and Pa02 are illustrated in Tables 4 and 5. Of note, although the FIo2 during the study varied from patient to patient, within each individual patient, the FIo2 was kept constant. Therefore, individual changes in Pa02 were not related to changes in FIo2. canadian health mall
Chronic hypoxemia has a major detrimental impact on the quality of life, exercise tolerance, overall morbidity, and survival in patients with COPD. This is directly related to hypoxemia-induced pulmonary hypertension, which is substantially worsened by physical exertion or acute bronchial or bronchopulmonary infections. Nocturnal oxyhemoglobin desaturation, which occurs during episodes of rapid eye movement sleep, also increases pulmonary vascular resistance. Chronic elevation of right ventricular afterload ultimately results in decompensation, with repeated episodes of right ventricular failure and multifocal atrial tachycardia.
Table 3—Oxygenation Variables
|Sv02, %||72 ±5||72 ±5||74±4f||74±4||75±4|
Table 4—PVRI: Individual Responses
Table 5—Arterial Oxygenation: Individual Responses