Impairment of ventilatory response to metabolic acidosis in insulin-dependent diabetic patients with advanced nephropathy

Sudden cardiopulmonary arrest due to a defective respiratory reflex is obse rved in diabetic patients impaired ventilatory response in diabetic patient s to acute hypoxia or hypercapnia induced by the inhalation of an artificia l gas has been reported Little is known regarding the respiratory compensat ory ability for mild to moderate metabolic acidosis due to renal failure in insulin-dependent diabetic subjects Arterial blood pH, HCO3-, PaCO2 and Pa O2 were measured in 13 insulin-dependent diabetic subjects with advanced ne phropathy and in 33 non-diabetic subjects with end-stage renal failure. The diabetic group consisted of six predialysis patients and seven on regular hemodialysis (HD) and the non-diabetic group, ten predialysis patients and 23 on HD. Differences between measured partial arterial pressure of carbon dioxide (PaCO2) and predicted PaCO2 determined from HCO, were examined PaCO 2 was significantly higher in the diabetic than in non-diabetic group (40.0 +/- 7.4 versus 31.1 +/- 5.1 mmHg, p < 0.05 in predialysis, 42.0 +/- 6.4 ve rsus 36.0 +/- 2.6 mmHg, p < 0.05 in HD), though plasma pH was essentially t he same for either. Differences in measured PaCO2 and predicted PaCO2 were significantly larger in the diabetic group than in non-diabetic group. Vent ilatory respose to uremic acidosis may thus be considered impaired in subje cts with advanced diabetic nephropathy.