EVALUATION OF VENTILATORY RESPONSES IN SEVERE ACIDEMIA IN DIABETIC-KETOACIDOSIS

Ventilatory response in patients with severe acidemia in diabetic keto acidosis (DKA) was unresolved. Thus, 83 patients with uncomplicated DK A were studied for the relation between arterial blood pH, calculated bicarbonate concentration (HCO3) and carbon dioxide tension (PCO2). Th e equation for the PCO2/HCO3 pair was: PCO2 = 1.58 x HCO3 + 7.6 (SE 2. 55, r = 0.95, p < 0.01); for the PCO2/pH pair was: PCO2 = 43.8 x pH-29 3 (SE 6.23, r = 0.66, p < 0.01). The correlation coefficient for the P CO2/HCO3 pair was significantly greater compared to the PCO2/pH pair ( p < 0.001). Multiple regression analysis showed that severe acidemia ( pH less than or equal to 7.10) per se was independently associated wit h PCO2 far the PCO2/HCO3 pair, but not for the PCO2/pH pair. Thus, our patients were divided into 2 groups for the PCO2/HCO3 pair: group 1 w ith pH less than or equal to 7.10 (n = 25) and group 2 with pH > 7.10 (n = 58). The equations were: group 1:PCO2 = 3.18 x HCO3 + 2.88 (SE 1. 72, r = 0.87, p < 0.01); group 2:PCO2 = 1.65 x HCO3 + 6.6 (SE 2.6, r = 0.95, p < 0.01). There was a significant difference between these 2 e quations (p < 0.01). Mathematical simulations with 10 sets of 25 or 58 random pH/PCO2 pairs (and calculated HCO3) for 'group 1' and 'group 2 ' also showed similar results, albeit with less precision. Hence, vent ilatory response in DKA varies between patients with severe acidemia a nd those with moderate acidemia by the PCO2/HCO3 pair, but not by the PCO2/pH pair.