Comparison of Hemodynamic Effects During Alveolar Recruitment Maneuvers in Spontaneously Hypertensive Rats Treated and Non-treated with Hydralazine

This article aims to evaluate the behavior of the arterial pressure response during alveolar recruitment maneuvers in spontaneously hypertensive rats (SHR). Such study can lead to a better understanding of arterial pressure behavior, which is relevant in the context of hypertension being a health condition. The animals were separated into groups: with and without Hydralazine treatment (20 mg/kg dissolved in drinking water) and two ages (17 weeks-2 weeks treatment and 21 weeks-6 weeks treatment). For the experiment, the animals were anesthetized, tracheostomized and connected to a small animal ventilator (flexiVent legacy, SCIREQ, Canada). The animals were connected to a custom-built arterial pressure monitor device. Arterial pressure and volume of the respiratory system were analyzed during two consecutive alveolar recruitment maneuvers. The results indicated that there is no statistically significant difference in arterial pressure during alveolar recruitment maneuvers, although respiratory system volume showed significant difference (p < 0.0001, ANOVA) among different groups. Regarding the percentage comparison between the period before ARM and the second ARM, there was statistical (p < 0.0001, ANOVA) difference in 17 weeks treated versus 21 weeks non-treated and 21 weeks treated versus (p > 0.05 for all). These findings could indicate that the drug, with the present dose and administration time, was not sufficient to decrease the basal pressure, however it influenced on the cardiovascular response during alveolar recruitment. Since there was no difference in the total air volume displacement in alveolar recruitment maneuvers among groups, the explanation to the influence on the cardiovascular response during alveolar recruitment is solely related with the cardiovascular system.