Ventilatory and Occlusion Pressure Responses to Hypercapnia in Patients with Chronic Renal Failure

Abstract

Little is known of the effect of chronic renal failure (CRF) on ventilatory regulation. In 38 subjects (19 healthy, 19 with CRF before and after dialysis), we performed measurements of ventilation (V_E) and occlusion pressure (P_0.1) while the subjects were breathing air and hypercapnic gas mixtures. The results have shown that (1) during air ventilation, CRF patients exhibited lower values of V_E and P_0.1, which returned to normal after dialysis; (2) during hypercapnic ventilation, CRF patients had the same response as healthy subjects for V_E but higher P_0.1 hemodialysis induced an upward shift of the CO₂ response curve in CRF patients. A twofold mechanism is probably involved: pulmonary edema, which reduces lung elasticity, and neuromuscular hypoexcitability, both implying a stronger central command.

Impact of Hemodialysis on Dyspnea and Lung Function in End Stage Kidney Disease Patients

“…To the best of our knowledge there are a few studies examining P 0.1 before and immediately after hemodialysis maintenance therapy [25, 26] in ESKD patients. In spontaneous breathing patients Sebert et al [26] examined the patient's P 0.1 relationship with the V E at different CO 2 concentrations, before and after hemodialysis maintenance.…”

“…In spontaneous breathing patients Sebert et al [26] examined the patient's P 0.1 relationship with the V E at different CO 2 concentrations, before and after hemodialysis maintenance. They found that for the same V E response CKD patients needed a higher neuromuscular ventilatory drive than normal subjects.…”

Disorders of Respiration and Sleep-Disordered Breathing in Patients with Chronic Renal Failure

“…A larger number of patients and a control group were included in this study. Although on air CRF patients had lower VE and P0,1 compared to controls, the hypercapnic response of P0,1 and the apneic threshold were increased [127].…”

“…The increased response had returned to baseline at 24 hours [125]. Sebert P et al report that HD did not change the slope of the response of P0,1 to hypercapnic stimulation but shifted the curve upwards [127], resulting to a lower apneic threshold and an increased minute ventilation for the same PCO 2 . Other investigators did not report increased sensitivity to CO 2 immediately after HD [126,132].…”

“…Hypocapnia can promote an unstable respiratory pattern (by decreasing the difference between awake PaCO 2 and apneic threshold) and precipitate apneas [118]. This destabilization may be further promoted by increases chemosensitivity to CO 2 [125,127,128]. Development of hypocapnia is also responsible for the unstable breathing pattern with central apneas observed during acetate HD in awake CRF patients [74].…”