Successful resuscitation in diabetic ketoacidosis: a strong case for the use of bicarbonate

Sodium bicarbonate therapy in patients with metabolic acidosis

Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated.

Bicarbonate in diabetic ketoacidosis - a systematic review

Objective

This study was designed to examine the efficacy and risk of bicarbonate administration in the emergent treatment of severe acidemia in diabetic ketoacidosis (DKA).

Methods

PUBMED database was used to identify potentially relevant articles in the pediatric and adult DKA populations. DKA intervention studies on bicarbonate administration versus no bicarbonate in the emergent therapy, acid-base studies, studies on risk association with cerebral edema, and related case reports, were selected for review. Two reviewers independently conducted data extraction and assessed the citation relevance for inclusion.

Results

From 508 potentially relevant articles, 44 were included in the systematic review, including three adult randomized controlled trials (RCT) on bicarbonate administration versus no bicarbonate in DKA. We observed a marked heterogeneity in pH threshold, concentration, amount, and timing for bicarbonate administration in various studies. Two RCTs demonstrated transient improvement in metabolic acidosis with bicarbonate treatment within the initial 2 hours. There was no evidence of improved glycemic control or clinical efficacy. There was retrospective evidence of increased risk for cerebral edema and prolonged hospitalization in children who received bicarbonate, and weak evidence of transient paradoxical worsening of ketosis, and increased need for potassium supplementation. No studies involved patients with an initial pH < 6.85.

Conclusions

The evidence to date does not justify the administration of bicarbonate for the emergent treatment of DKA, especially in the pediatric population, in view of possible clinical harm and lack of sustained benefits.

Comparative study of different insulin regimens in management of diabetic ketoacidosis

36 patients in severe diabetic ketoacidosis were studied prospectively. All patients were treated with small doses of insulin, the first 18 by the intramuscular route and the remainder by continuous intravenous infusion. These patients were compared with 25 ketoacidotic patients who were treated with large intravenous boluses of insulin. With the intramuscular regimen there was a slower fall of blood-sugar than with intravenous insulin administered either in boluses or as a continuous infusion. The acidosis took longer to correct when small doses of insulin were used. In practice a long time interval between correction of the hyperglycaemia and correction of the acidosis may be a problem when the continuous infusion of insulin is used. Potassium requirements during treatment were identical (30-40 mmol/l fluid infused) and independent of the insulin regimen. However, small doses of insulin led to a poor retention of potassium. In the management of diabetic ketoacidosis the mode of administration of insulin is of limited significance, and small doses, although effective in most cases, are not clearly superior to conventional treatment with large doses.