Hyperventilation in severe diabetic ketoacidosis

Increased Use of Hyperosmolar Therapy for Suspected Clinically Apparent Brain Injury in Pediatric Patients with Diabetic Ketoacidosis during the Peak of the COVID-19 Pandemic

The incidence of pediatric diabetic ketoacidosis (DKA) increased during the peak of the COVID-19 pandemic. The objective of this study was to investigate whether rates of hyperosmolar therapy administration for suspected clinically apparent brain injury (CABI) complicating DKA also increased during this period as compared to the three years immediately preceding the pandemic and to compare the characteristics of patients with suspected CABI before the pandemic, patients with suspected CABI during the peak of the pandemic, and those with DKA but without suspected CABI during the pandemic. Patients aged ≤18 years presenting with DKA before (March 11, 2017-March 10, 2020) and during the peak of the pandemic (March 11, 2020-March 10, 2021) were identified through a rigorous search of two databases. Predefined criteria were used to diagnose suspected CABI. Biochemical, clinical, and sociodemographic data were collected from a comprehensive review of the electronic medical record. The proportion of patients with DKA who received hyperosmolar therapy was significantly higher (P = 0.014) during the pandemic compared to the prepandemic period; however, this was only significant among patients with newly diagnosed diabetes. Both groups with suspected CABI had more severe acidosis, lower Glasgow Coma Scale scores, and longer hospital admissions (P< 0.001 for all) than cases without suspected CABI. During the pandemic, the blood urea nitrogen concentration was significantly higher in patients with suspected CABI than those without suspected CABI, suggesting they were more severely dehydrated. The clinical, biochemical, and sociodemographic characteristics of patients with suspected CABI were indistinguishable before and during the pandemic. In conclusion, administration of hyperosmolar therapy for suspected CABI was more common during the peak of the COVID-19 pandemic, possibly a result of delayed presentation, highlighting the need for increased awareness and early recognition of the signs and symptoms of diabetes and DKA, especially during future surges of highly transmissible infections.

Acid-base balance and cerebrovascular regulation

The regulation and defence of intracellular pH is essential for homeostasis. Indeed, alterations in cerebrovascular acid-base balance directly affect cerebral blood flow (CBF) which has implications for human health and disease. For example, changes in CBF regulation during acid-base disturbances are evident in conditions such as chronic obstructive pulmonary disease and diabetic ketoacidosis. The classic experimental studies from the past 75+ years are utilized to describe the integrative relationships between CBF, carbon dioxide tension (PCO₂ ), bicarbonate (HCO₃ ^- ) and pH. These factors interact to influence (1) the time course of acid-base compensatory changes and the respective cerebrovascular responses (due to rapid exchange kinetics between arterial blood, extracellular fluid and intracellular brain tissue). We propose that alterations in arterial [HCO₃ ^- ] during acute respiratory acidosis/alkalosis contribute to cerebrovascular acid-base regulation; and (2) the regulation of CBF by direct changes in arterial vs. extravascular/interstitial PCO₂ and pH - the latter recognized as the proximal compartment which alters vascular smooth muscle cell regulation of CBF. Taken together, these results substantiate two key ideas: first, that the regulation of CBF is affected by the severity of metabolic/respiratory disturbances, including the extent of partial/full acid-base compensation; and second, that the regulation of CBF is independent of arterial pH and that diffusion of CO₂ across the blood-brain barrier is integral to altering perivascular extracellular pH. Overall, by realizing the integrative relationships between CBF, PCO₂ , HCO₃ ^- and pH, experimental studies may provide insights to improve CBF regulation in clinical practice with treatment of systemic acid-base disorders.

Application of bench studies at the bedside to improve outcomes in the management of severe diabetic ketoacidosis in children-a narrative review

OBJECTIVE

In this review, we address a few key issues and the challenges faced in the management of severe diabetic ketoacidosis (DKA) in children, highlighting the existing standard of care, supported by evidence and bench studies.

BACKGROUND

The classic triad of DKA namely hyperglycemia, metabolic acidosis and ketonemia warrants immediate attention with fluids and insulin. Correction of dehydration in DKA is of utmost priority and the calculation of fluid volume and choice of fluid have remained a matter of debate. Insulin therapy, to halt the ketone production, in DKA has undergone wide variations in dose and preparation since its discovery. Although the mortality due to severe DKA has remarkably decreased, complications like cerebral edema and acute kidney injury (AKI) continue to haunt the intensivists and endocrinologists on a few occasions.

METHODS

We have selected a few important questions in the management of severe DKA in children, addressing the challenges, reviewing the studies, guidelines and bedside practices with evidence in this narrative review.

CONCLUSIONS

The focus of management should be to understand and normalise the deranged physiology rather than trying to get normal laboratory reports. This needs careful understanding of the pathogenesis and deriving conclusion from bench studies. With newer studies and evidence, guidelines are revised every few years. There is a trend towards more conservative therapy, with continuous and advanced monitoring. Switching to subcutaneous insulin and oral hydration is done as early as possible with clinical monitoring and resolution of DKA. Management of severe DKA in children can vary from simple fluid titration and insulin infusion in mild cases to a scenario with multiorgan dysfunction requiring intensive monitoring and advanced organ support. Individualisation of therapy to suit the needs with the available evidence and expertise is extremely essential.

Brain injury in children with diabetic ketoacidosis: Review of the literature and a proposed pathophysiologic pathway for the development of cerebral edema

Cerebral edema (CE) is a potentially devastating complication of diabetic ketoacidosis (DKA) that almost exclusively occurs in children. Since its first description in 1936, numerous risk factors have been identified; however, there continues to be uncertainty concerning the mechanisms that lead to its development. Currently, the most widely accepted hypothesis posits that CE occurs as a result of ischemia-reperfusion injury, with inflammation and impaired cerebrovascular autoregulation contributing to its pathogenesis. The role of specific aspects of DKA treatment in the development of CE continues to be controversial. This review critically examines the literature on the pathophysiology of CE and attempts to categorize the findings by types of brain injury that contribute to its development: cytotoxic, vasogenic, and osmotic. Utilizing this scheme, we propose a multifactorial pathway for the development of CE in patients with DKA.

A Rare and Lethal Complication: Cerebral Edema in the Adult Patient with Diabetic Ketoacidosis

Commonly seen in the emergency department, diabetic ketoacidosis is a potentially lethal sequela of uncontrolled diabetes mellitus. In the adult population, a rare complication of diabetic ketoacidosis is cerebral edema. This case report discusses a 26-year-old male with new onset diabetes mellitus who developed cerebral edema leading to death.

Mechanical Ventilation during Acute Brain-Injury in Children

Mechanical ventilation in the brain-injured pediatric patient requires many considerations, including the type and severity of lung and brain injury and how progression of such injury will develop. This review focuses on neurological breathing patterns at presentation, the effect of brain injury on the lung, developmental aspects of blood gas tensions on cerebral blood flow, and strategies used during mechanical ventilation in infants and children receiving neurological intensive care. Taking these basic principles, our clinical approach is informed by balancing the blood gas tension targets that follow from the ventilation support we choose and the intracranial consequences of these choices on vascular and hydrodynamic physiology. As such, we are left with two key decisions: a low tidal volume strategy for the lung versus the consequence of hypercapnia on the brain; and the use of positive end expiratory pressure to optimize oxygenation versus the consequence of impaired cerebral venous return from the brain and resultant intracranial hypertension.

Brain cell swelling during hypocapnia increases with hyperglycemia or ketosis

BACKGROUND

Severe hypocapnia reduces cerebral blood flow (CBF) and is known to be a risk factor for diabetic ketoacidosis (DKA)-related cerebral edema and cerebral injury in children. Reductions in CBF resulting from hypocapnia alone, however, would not be expected to cause substantial cerebral injury. We hypothesized that either hyperglycemia or ketosis might alter the effects of hypocapnia on CBF and/or cerebral edema associated with CBF reduction.

METHODS

We induced hypocapnia (pCO₂ 20 ± 3 mmHg) via mechanical ventilation in three groups of juvenile rats: 25 controls, 22 hyperglycemic rats (serum glucose 451 ± 78 mg/dL), and 15 ketotic rats (β-hydroxy butyrate 3.0 ± 1.0 mmol/L). We used magnetic resonance imaging to measure CBF and apparent diffusion coefficient (ADC) values in these groups and in 17 ventilated rats with normal pCO₂ (40 ± 3 mmHg). In a subset (n = 35), after 2 h of hypocapnia, pCO₂ levels were normalized (40 ± 3 mmHg) and ADC and CBF measurements were repeated.

RESULTS

Declines in CBF with hypocapnia occurred in all groups. Normalization of pCO₂ after hypocapnia resulted in hyperemia in the striatum. These effects were not substantially altered by hyperglycemia or ketosis. Declines in ADC (suggesting brain cell swelling) during hypocapnia, however, were greater during both hyperglycemia and ketosis.

CONCLUSIONS

We conclude that brain cell swelling associated with hypocapnia is increased by both hyperglycemia and ketosis, suggesting that these metabolic conditions may make the brain more vulnerable to injury during hypocapnia.

Cerebral edema in children with diabetic ketoacidosis: vasogenic rather than cellular?

Cerebral edema (CE) is accumulation of water in the intracellular or extracellular spaces of the brain. Vasogenic edema occurs when there is breakdown of the tight endothelial junctions of the blood-brain barrier (BBB), leading to extravasation of intravascular protein and fluid into the interstitial space of the brain. In cellular edema the BBB remains intact and there is swelling of astrocytes with corresponding reduction in extracellular space. In this review we bring together clinical evidence from neuropathology and cerebral magnetic resonance (MR) studies in pediatric patients presenting in diabetic ketoacidosis (DKA), and use applied physiology to understand whether CE complicating DKA is vasogenic, rather than cellular in origin. Because the first-line of defense against CE is the interface between the intravascular compartment and the extracellular space in the brain much of the focus in this review is the BBB. The principal pathologic finding in fatal cases is perivascular with BBB disruption and albumin extravasation, suggesting increased vascular permeability. DKA induces an inflammatory response and the mechanism of BBB transcellular permeability may be an immunologic cascade that disrupts tight junctions. The principal MR finding in subclinical cases of CE is vasogenic rather than cellular edema. We propose that the following physiology be considered when treating cases: bolus dose of intravenous mannitol may result in fall in serum sodium concentration, and therefore clinical worsening. Failure to respond to mannitol should prompt the use of 3% hypertonic saline (HS). Bolus dose of intravenous 3% HS is expected to effect vasogenic edema provided that the reflection coefficient is close to 1. Failure to respond to 3% HS should prompt the use of mannitol.

Effects of gas exchange on acid-base balance

This paper describes the interactions between ventilation and acid-base balance under a variety of conditions including rest, exercise, altitude, pregnancy, and various muscle, respiratory, cardiac, and renal pathologies. We introduce the physicochemical approach to assessing acid-base status and demonstrate how this approach can be used to quantify the origins of acid-base disorders using examples from the literature. The relationships between chemoreceptor and metaboreceptor control of ventilation and acid-base balance summarized here for adults, youth, and in various pathological conditions. There is a dynamic interplay between disturbances in acid-base balance, that is, exercise, that affect ventilation as well as imposed or pathological disturbances of ventilation that affect acid-base balance. Interactions between ventilation and acid-base balance are highlighted for moderate- to high-intensity exercise, altitude, induced acidosis and alkalosis, pregnancy, obesity, and some pathological conditions. In many situations, complete acid-base data are lacking, indicating a need for further research aimed at elucidating mechanistic bases for relationships between alterations in acid-base state and the ventilatory responses.

Common endocrine issues in the pediatric intensive care unit

Thyroid hormone is central to normal development and metabolism. Abnormalities in thyroid function in North America often arise from autoimmune diseases, but they rarely present as critical illness. Severe deficiency or excess of thyroid hormone both represent life-threatening disease, which must be treated expeditiously and thoroughly. Such deficiencies must be considered, because presentation may be nonspecific.

Current concepts and controversies in prevention and treatment of diabetic ketoacidosis in children

Diabetic ketoacidosis (DKA) is caused by absolute or relative lack of insulin. Lack of insulin leads to hyperglycemia, ketonemia, and acidosis. Prevalence of DKA at diagnosis of type 1 diabetes (T1D) varies around the world from 18 % to 84 %. Incidence of recurrent DKA is higher among females, insulin pump users, those with a history of psychiatric or eating disorder, and suboptimal socioeconomic circumstances. DKA is the most common cause of death in children with T1D. Children with DKA should be treated in experienced centers. Initial bolus of 10-20 mL/kg 0.9 % saline is followed by 0.45 %-0.9 % saline infusion. Fluid infusion should precede insulin administration (0.1 U/kg/h) by 1-2 hours. The prevention of DKA at diagnosis of diabetes can be achieved by an intensive community intervention and education of health care providers to raise awareness. Prevention of recurrent DKA requires continuous patient education and access to diabetes programs and telephone services.

Intracranial pressure/cerebral perfusion pressure-targeted management of life-threatening intracranial hypertension complicating diabetic ketoacidosis-associated cerebral edema: a case report

Symptomatic cerebral edema from diabetic ketoacidosis occurs infrequently but carries a high rate of mortality and morbidity owing to complications from intracranial hypertension. Treatment options are limited but include hyperosmolar therapy with mannitol or hypertonic saline, tracheal intubation for airway protection, and hyperventilation via mechanical ventilation. We describe here the successful use of an intracranial pressure/cerebral perfusion pressure-targeted management strategy through ventriculostomy catheter placement with intracranial pressure monitoring and cerebrospinal fluid drainage, hyperosmolar therapy with hypertonic saline, and controlled hyperventilation to treat life-threatening complications of cerebral edema in a pediatric patient with severe diabetic ketoacidosis.

Life-saving decompressive craniectomy for diffuse cerebral edema during an episode of new-onset diabetic ketoacidosis: case report and review of the literature

PURPOSE

Diabetic ketoacidosis (DKA), a well-known complication of diabetes mellitus, is associated with severe diffuse cerebral edema leading to brain herniation and death. Survival from an episode of symptomatic cerebral edema has been associated with debilitating neurological sequelae, including motor deficits, visual impairment, memory loss, seizures, and persistent vegetative states. A review of the literature reveals scant information regarding the potential surgical options for these cases. The authors present their case in which they used a craniectomy to treat this life-threatening condition.

METHODS

After reportedly suffering nausea and vomiting, a 12-year-old male presented to the emergency room with lethargy and was diagnosed with acute DKA. After appropriate treatment, the patient became comatose. A CT scan revealed diffuse cerebral edema. To decrease intracranial pressure and prevent further progression of brain herniation, a bifrontal decompressive craniectomy with duraplasty was performed.

RESULTS

The patient's neurological function gradually improved, and he returned to school and his regular activities with only minimal cognitive deficits.

CONCLUSION

Given the high mortality and morbidity associated with DKA-related edema, we believe decompressive craniectomy should be considered for malignant cerebral edema and herniation syndrome.

Alternative management of diabetic ketoacidosis in a Brazilian pediatric emergency department

DKA is a severe metabolic derangement characterized by dehydration, loss of electrolytes, hyperglycemia, hyperketonemia, acidosis and progressive loss of consciousness that results from severe insulin deficiency combined with the effects of increased levels of counterregulatory hormones (catecholamines, glucagon, cortisol, growth hormone). The biochemical criteria for diagnosis are: blood glucose > 200 mg/dl, venous pH <7.3 or bicarbonate <15 mEq/L, ketonemia >3 mmol/L and presence of ketonuria. A patient with DKA must be managed in an emergency ward by an experienced staff or in an intensive care unit (ICU), in order to provide an intensive monitoring of the vital and neurological signs, and of the patient's clinical and biochemical response to treatment. DKA treatment guidelines include: restoration of circulating volume and electrolyte replacement; correction of insulin deficiency aiming at the resolution of metabolic acidosis and ketosis; reduction of risk of cerebral edema; avoidance of other complications of therapy (hypoglycemia, hypokalemia, hyperkalemia, hyperchloremic acidosis); identification and treatment of precipitating events. In Brazil, there are few pediatric ICU beds in public hospitals, so an alternative protocol was designed to abbreviate the time on intravenous infusion lines in order to facilitate DKA management in general emergency wards. The main differences between this protocol and the international guidelines are: intravenous fluid will be stopped when oral fluids are well tolerated and total deficit will be replaced orally; if potassium analysis still indicate need for replacement, it will be given orally; subcutaneous rapid-acting insulin analog is administered at 0.15 U/kg dose every 2-3 hours until resolution of metabolic acidosis; approximately 12 hours after treatment initiation, intermediate-acting (NPH) insulin is initiated at the dose of 0.6-1 U/kg/day, and it will be lowered to 0.4-0.7 U/kg/day at discharge from hospital.

Diabetic ketoacidosis: a current appraisal of pathophysiology and management

Diabetic ketoacidosis (DKA) is a frequent abnormal metabolic entity seen in high-dependency units such as critical care units and in the emergency department. Having an understanding of its pathophysiology, a consequence of absent to low insulin levels, delineates the clinical presentation. Most clinical features are caused by hyperglycemia and acidosis, including weight loss. The newer management modalities are discussed that include the need for intensive laboratory workup, meticulous monitoring of the insulin, and fluid management. Among the complications, cerebral edema (CE) is the most dreaded, albeit with low incidence. The new insights into its pathophysiology and management are outlined, and a timeline for management of DKA is proposed.

Management of diabetic ketoacidosis in children and adolescents

Diabetic ketoacidosis (DKA) is a life-threatening complication of diabetes mellitus. While it can occur in all types of diabetes mellitus, it is seen most often in patients with type 1 diabetes, either at presentation or as a result of non-compliance with medical therapy. DKA is characterized by hyperglycemia, acidosis, dehydration, and electrolyte abnormalities, which result from a deficiency of insulin and an excess of counter-regulatory hormones. Therapy is aimed at repleting fluids, and correcting acidosis and electrolyte disturbances by administration of intravenous fluid and intravenous insulin. Rapid correction should be avoided as it may result in untoward effects, including cerebral edema. Frequent monitoring of neurologic status and metabolic parameters aids in avoidance or early detection of complications. While much is still not understood about the most serious complication, cerebral edema, recent studies suggest that its development may be tied to a loss of cerebral autoregulation and a vasogenic mechanism of edema formation. Treatment of cerebral edema includes fluid restriction and administration of mannitol. Once DKA has resolved, subcutaneous insulin is initiated with careful consideration of its pharmacokinetics to avoid a period of insulin deficiency and metabolic decompensation.

Cerebral edema in diabetic ketoacidosis

OBJECTIVE

To review the causes of cerebral edema in diabetic ketoacidosis (CEDKA), including pathophysiology, risk factors, and proposed mechanisms, to review the diagnosis, treatment, and prognosis of CEDKA and the treatment of diabetic ketoacidosis as it pertains to prevention of cerebral edema.

DATA SOURCE

A MEDLINE search using OVID was done through 2006 using the search terms cerebral edema and diabetic ketoacidosis. RESULTS OF SEARCH: There were 191 citations identified, of which 150 were used. An additional 42 references listed in publications thus identified were also reviewed, and two book chapters were used.

STUDY SELECTION

The citations were reviewed by the author. All citations identified were used except 25 in foreign languages and 16 that were duplicates or had inappropriate titles and/or subject matter. Of the 194 references, there were 21 preclinical and 40 clinical studies, 35 reviews, 15 editorials, 43 case reports, 29 letters, three abstracts, six commentaries, and two book chapters.

DATA SYNTHESIS

The data are summarized in discussion.

CONCLUSIONS

The causes and mechanisms of CEDKA are unknown. CEDKA may be due as much to individual biological variance as to severity of underlying metabolic derangement of the child's state and/or treatment risk factors. Treatment recommendations for CEDKA and diabetic ketoacidosis are made taking into consideration possible mechanisms and risk factors but are intended as general guidelines only in view of the absence of conclusive evidence.

Combined insulin and bicarbonate therapy elicits cerebral edema in a juvenile mouse model of diabetic ketoacidosis

Cerebral edema in diabetic ketoacidosis (DKA-CE) occurs primarily in children and can develop during DKA therapy. The treatment factors contributing to DKA-CE remain elusive. Our objectives were to characterize an age-appropriate DKA mouse model and to determine which DKA therapies contribute to DKA-CE. Juvenile mice were briefly fed a high-fat diet and injected with two pancreatic beta-cell toxins: streptozocin and alloxan. Severe insulin and leptin deficiencies associated with hyperosmolar ketoacidosis rapidly developed, indicating DKA. DKA mice were treated with re-hydration +/- insulin and brain water content (BWC) measured as an indicator of DKA-CE. As expected, glucose and beta-OH-butyrate corrected in DKA mice that received rehydration and insulin. BWC significantly increased above control levels only in DKA mice that received combined insulin and bicarbonate therapy, indicating the development of DKA-CE. Microscopically, DKA-CE brains had perineuronal and perivascular edema, with microvacuolation in the white matter tracts. These results indicate that insulin-deficient juvenile mice develop biochemical changes that are similar to those of DKA in children. Increased BWC was observed only in DKA mice that received combined insulin and bicarbonate therapy, suggesting that rapid systemic alkalinization in the presence of insulin may contribute to DKA-CE.