Psychogenic dyspnea and hypocapnia in men with ischemic heart disease before and after CABG

Abstract

The goal of the study was to compare the rate of psychogenic dyspnea (PD) and hypocapnia in patients with ischemic heart disease (IHD) before and after CABG. We studied the objective signs of PD and hypocapnia, such as psychogenic dyspnea coefficient (PDC) and СО ₂ concentration in the expired air finite portion (FetCО ₂) in 47 male patients with IHD and 34 healthy men by using spirometry and capnometry. We also performed a comparative analysis of the above-mentioned parameters before and after CABG. The arrhythmic breathing rate (PDC>40) in patients with IHD was 2.6 times higher than that in healthy men, and the hypocapnia rate (FetCО ₂<4.5%) was 3.6 times higher than that in the control group. The data obtained were confirmed by the group mean values of PDC and FetCО ₂. Thus, PDC in the IHD cohort was significantly higher, and FetCО ₂ lower than in healthy men (4.60.4 and 5.20.3 respectively, р<0.05). On the 8-10 ^th postoperative day there was a 1.3 times increase in patients with PDC>40, and a 1.7 times increase in hypocapnia patients, with the mean FetCО ₂ level decreasing from 4.60.4 before surgery down to 4.00.7 after CABG (р<0,05). Thus, psychogenic dyspnea or neurogenic hyperventilation (NH), as well as the resulted hypocapnia, are documented in IHD patients. Because of its negative cardiovascular effects, NH requires timely diagnosis and correction before and after coronary revascularization surgery.