A physicochemical acid-base approach for managing diabetic ketoacidosis

Plasma volume expansion reveals hidden metabolic acidosis in patients with diabetic ketoacidosis

Background

Hyperchloremic metabolic acidosis that develops during the treatment of diabetic ketoacidosis is usually attributed to the chloride content of resuscitation fluids. We explored an alternative explanation, namely that fluid-induced plasma volume expansion alters the absolute differences in the concentrations of sodium and chloride (the Na–Cl gap) enough to affect the acid–base balance. We analyzed data from a prospective single-center cohort study of 14 patients treated for diabetic ketoacidosis. All patients received 1 L of 0.9% saline over 30 min on two consecutive days. Blood gases were sampled before and after the infusions.

Results

The initial plasma volume was estimated to be 25 ± 13% (mean ± SD) below normal on admission to the intensive care unit. At that time, most patients had an increased actual Na–Cl gap, which counteracts acidosis. However, the correction of the plasma volume deficit revealed that these patients would have had a decreased Na–Cl gap upon admission if they had been normovolemic at that time; the estimated “virtual Na–Cl gap” of 29 ± 5 mmol/L was significantly lower than the uncorrected value, which was 39 ± 5 mmol/L (P < 0.001). On Day 2, most patients had a decreased actual Na–Cl gap (33 ± 5 mmol/L), approaching the corrected value on Day 1.

Conclusions

The hyperchloremic acidosis commonly seen in diabetic ketoacidosis may not be primarily caused by the chloride content of resuscitation fluids but, rather, by the restoration of plasma volume, which reveals the hidden metabolic acidosis caused by a decreased Na–Cl gap.

Trial registration Clinical Trials Identifier NCT02172092, registered June 24, 2014, https://www.clinicaltrials.gov/NCT02172092

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00464-5.

Case Report: Role of Ketone Monitoring in Diabetic Ketoacidosis With Acute Kidney Injury: Better Safe Than Sorry

BACKGROUND

Type 1 Diabetes (T1D) is a well-known endocrinological disease in children and adolescents that is characterized by immune-mediated destruction of pancreatic β-cells, leading to partial or total insulin deficiency, with an onset that can be subtle (polydipsia, polyuria, weight loss) or abrupt (Diabetic Keto-Acidosis, hereafter DKA, or, although rarely, Hyperosmolar Hyperglycemic State, hereafter HHS). Severe DKA risk at the onset of T1D has recently significantly increased during the SARS-CoV-2 pandemic with life-threatening complications often due to its management. DKA is marked by low pH (<7.3) and bicarbonates (<15 mmol/L) in the presence of ketone bodies in plasma or urine, while HHS has normal pH (>7.3) and bicarbonates (>15 mmol/L) with no or very low ketone bodies. Despite this, ketone monitoring is not universally available, and DKA diagnosis is mainly based on pH and bicarbonates. A proper diagnosis of the right form with main elements (pH, bicarbonates, ketones) is essential to begin the right treatment and to identify organ damage (such as acute kidney injury).

CASE PRESENTATIONS

In this series, we describe 3 case reports in which the onset of T1D was abrupt with severe acidosis (pH < 7.1) in the absence of both DKA and HHS. In a further evaluation, all 3 patients showed acute kidney injury, which caused low bicarbonates and severe acidosis without increasing ketone bodies.

CONCLUSION

Even if it is not routinely recommended, a proper treatment that included bicarbonates was then started, with a good response in terms of clinical and laboratory values. With this case series, we would like to encourage emergency physicians to monitor ketones, which are diriment for a proper diagnosis and treatment of DKA.

Physicochemical Models of Acid-Base

Physicochemical models have played an important role in understanding, diagnosing, and treating acid-base disorders for more than 100 years. This review focuses on recent complex models, solved using computers, and shows how these models provide new understanding and diagnostic approaches in acid-base disorders. These advanced models use the following physicochemical principles: (1) chemical equilibrium, (2) conservation of mass, (3) electroneutrality, and (4) osmotic equilibrium to describe the steady-state distribution of H₂O and ions in the four major body-fluid spaces, cells, interstitium, plasma, and erythrocytes, and show how this distribution is changed by fluid infusions and losses through renal and gastrointestinal physiological processes. Illustrations of model use with a new comprehensive diagnostic approach are the understanding of an important clinical situation, saline acidosis, and the diagnosis of a patient with diabetic ketoacidosis. This new approach predicts a patient's whole-body base excess and partitions this value into 10 individual values, producing the disorder. These data and other data produced by the diagnostic model described in this review provide much more extensive insight than previous approaches.

Plasma-Lyte 148 vs 0.9% saline for fluid resuscitation in diabetic ketoacidosis

PURPOSE

The purpose of the study was to determine the effects of Plasma-Lyte 148 (PL) vs 0.9% saline (NS) fluid resuscitation in diabetic ketoacidosis (DKA).

METHODS

A multicenter retrospective analysis of adults admitted for DKA to the intensive care unit, who received almost exclusively PL or NS infusion up until 12 hours, was performed.

RESULTS

Nine patients with PL and 14 patients with NS were studied. Median serum bicarbonate correction was higher in the PL vs NS groups at 4 to 6 hours (8.4 vs 1.7 mEq/L) and 6 to 12 hours (12.8 vs 6.2 mEq/L) from baseline (P < .05). Median standard base excess improved by 10.5 vs 4.2 mEq/L at 4 to 6 hours and by 16.0 vs 9.1 mEq/L at 6 to 12 hours in the PL and NS groups, respectively (P < .05). Chloride levels increased significantly in the NS vs PL groups over 24 hours. Potassium levels were lower at 6 to 12 hours in the PL group. Mean arterial blood pressure was higher at 2 to 4 hours in the PL group, whereas cumulative urine output was lower at 4 to 6 hours in the NS group. There were no differences in glycemic control or duration of intensive care unit stay.

CONCLUSION

Patients with DKA resuscitated with PL instead of NS had faster initial resolution of metabolic acidosis and less hyperchloremia, with a transiently improved blood pressure profile and urine output.