OBJECTIVE: To evaluate the impact of respiratory alkalosis on the elimination of intravenously infused lactate. DESIGN: Prospective, randomized, crossover study. SETTING: Medical ICU of a university hospital. PATIENTS: Eight patients treated by ventilatory support for neurologic or neuromuscular diseases. INTERVENTIONS: Patients were investigated on two occasions: during normoventilation (pH 7.42 +/- 0.1, PCO2 41 +/- 2 torr [5.5 +/- 0.2 kPa]) and during respiratory alkalosis (pH 7.59 +/- 0.1, PCO2 27 +/- 2 torr [3.6 +/- 0.2 kPa]) induced by controlled hyperventilation. To evaluate lactate elimination kinetics, 1 mmol/kg body weight of L-lactic acid was infused over 5 mins. MEASUREMENTS AND MAIN RESULTS:Arterial lactate concentrations and blood gas values were determined before and repeatedly after the infusion. Lactate elimination variables were calculated from the plasma curve by using a two-compartment model. Respiratory alkalosis increased plasma lactate from 1.56 +/- 0.1 to 2.49 +/- 0.2 mmol/L (p less than .001). The lactate elimination half-life increased from 4.57 +/- 0.2 mins at pH 7.42, to 9.96 +/- 1.1 mins during pH 7.59 (p less than .01), and beta half-life increased from 12.2 +/- 1.9 to 44.1 +/- 1 mins (p less than .01). Whole-body clearance decreased 40% from 24.2 +/- 2.9 to 14.3 +/- 2.0 mL/kg body weight-min (p less than .01). CONCLUSIONS:Respiratory alkalosis increases the basal concentration of plasma lactate and decreases clearance of infused lactic acid. These findings provide further evidence of the adverse effects of alkalosis.
RCT Entities:
OBJECTIVE: To evaluate the impact of respiratory alkalosis on the elimination of intravenously infused lactate. DESIGN: Prospective, randomized, crossover study. SETTING: Medical ICU of a university hospital. PATIENTS: Eight patients treated by ventilatory support for neurologic or neuromuscular diseases. INTERVENTIONS:Patients were investigated on two occasions: during normoventilation (pH 7.42 +/- 0.1, PCO2 41 +/- 2 torr [5.5 +/- 0.2 kPa]) and during respiratory alkalosis (pH 7.59 +/- 0.1, PCO2 27 +/- 2 torr [3.6 +/- 0.2 kPa]) induced by controlled hyperventilation. To evaluate lactate elimination kinetics, 1 mmol/kg body weight of L-lactic acid was infused over 5 mins. MEASUREMENTS AND MAIN RESULTS: Arterial lactate concentrations and blood gas values were determined before and repeatedly after the infusion. Lactate elimination variables were calculated from the plasma curve by using a two-compartment model. Respiratory alkalosis increased plasma lactate from 1.56 +/- 0.1 to 2.49 +/- 0.2 mmol/L (p less than .001). The lactate elimination half-life increased from 4.57 +/- 0.2 mins at pH 7.42, to 9.96 +/- 1.1 mins during pH 7.59 (p less than .01), and beta half-life increased from 12.2 +/- 1.9 to 44.1 +/- 1 mins (p less than .01). Whole-body clearance decreased 40% from 24.2 +/- 2.9 to 14.3 +/- 2.0 mL/kg body weight-min (p less than .01). CONCLUSIONS:Respiratory alkalosis increases the basal concentration of plasma lactate and decreases clearance of infused lactic acid. These findings provide further evidence of the adverse effects of alkalosis.
Authors: Mark Hatherill; Shamiel Salie; Zainab Waggie; John Lawrenson; John Hewitson; Louis Reynolds; Andrew Argent Journal: Intensive Care Med Date: 2007-03-22 Impact factor: 17.440
Authors: Paul A van Beest; Lukas Brander; Sebastiaan Pa Jansen; Johannes H Rommes; Michaël A Kuiper; Peter E Spronk Journal: Ann Intensive Care Date: 2013-02-27 Impact factor: 6.925