occurs intracellularly, extracellularly, and in the cerebrospinal fluid (CSF). Adding sodium bicarbonate to the extracellular fluid causes a decrease in hydrogen ions with subsequent increase in carbon dioxide (CO2) concentration. Since CO2) but not bicarbonate, readily diffuses across cell membranes and into the CSF, this leads to an increase in intracellular and CSF CO2 concentration, with co...

Left ventricular (LV) contractile dysfunction during acidosis has been reported to be almost reversible in crystalloidperfused hearts after correction of acidosis. In contrast, we have found that, in blood-perfused hearts, contractile function is paradoxically depressed after correction of acidosis with a transient overshoot of contractility during the recovery of pH. To clarify the mechanism o...

INTRODUCTION Acute metabolic acidosis of non-renal origin is usually a result of either lactic or ketoacidosis, both of which are associated with a high anion gap. There is increasing recognition, however, of a group of acidotic patients who have a large anion gap that is not explained by either keto- or lactic acidosis nor, in most cases, is inappropriate fluid resuscitation or ingestion of ex...

THE PREOPTIC AREA and anterior hypothalamus (POAH) is regarded as the primary site for thermoreception in the mammalian brain. Peripheral thermal afferents synapse on temperature-sensitive neurons in the POAH. The POAH, in particular, contains a high concentration of warm-sensitive neurons, which are proposed to activate heat-loss responses while inhibiting heat-production. Accordingly, electri...

This report attempts to frame the debate about clinical administration of sodium bicarbonate in the setting of lactic acidosis in terms of simple questions. Specifically, we address why we develop lactic acidosis in some circumstances, how acute lactic acidosis impairs cardiovascular function and why sodium bicarbonate may have deleterious effects which limit its utility. We also attempt to exp...

Renal tubular acidosis (RTA) is a non-uremic defects of urinary acidification. It is characterized by a normal anion gap hyperchloremic metabolic acidosis; plasma potassium may be normal, low or highdepending on the type of RTA. These syndromes differ from uremic acidosis which is associated with a high anion gap, decreased glomerular filtration with enhanced proton secretion by the remaining n...

Biguanide poisoning is associated with lactic acidosis. The exact mechanism of biguanide-induced lactic acidosis is not well understood. In the previous issue of Critical Care, Protti and colleagues demonstrated that biguanide-induced lactic acidosis may be due in part to a reversible inhibition of mitochondrial respiration. Thus, in the absence of an antidote, increased drug elimination throug...

Amlal, Hassane, Sulaiman Sheriff, and Manoocher Soleimani. Upregulation of collecting duct aquaporin-2 by metabolic acidosis: role of vasopressin. Am J Physiol Cell Physiol 286: C1019–C1030, 2004. First published December 24, 2003; 10.1152/ajpcell.00394. 2003.—Metabolic acidosis is associated with alteration in fluid and electrolyte reabsorption in a number of nephron segments. However, the eff...

The clinical features, arterial blood gases, and acid-base profile were examined in 229 consecutive episodes of acute asthma in 170 patients who required hospitalization. A simple respiratory alkalosis was the most common acid-base disturbance, occurring in 48 percent of the episodes. Metabolic acidosis, either alone or as part of a mixed disturbance, was noted in 28 percent. Of 60 episodes pre...