Download HYPEROSMOLAR NON-KETOTIC COMA Standard Care for

HYPEROSMOLAR NON-KETOTIC COMA
Diagnosis and management guidelines for hyperglycemic crises are available from the American Diabetes
Association. The following criteria have been adopted:
• Hypovolaemia.
• Marked hyperglycaemia (30mmol/L or more).
• No significant ketonaemia (<3mmol/L) or acidosis (pH >7.3,
bicarbonate>15mmo/L).
• Osmolality usually ≥320mmol/kg. (Calculated osmolality = 2 Na + glucose+urea)
The main goals in the treatment of hyperosmolar hyperglycemic state (HHS) are as
follows:
•
•
•
•
To vigorously rehydrate the patient while maintaining electrolyte homeostasis
To correct hyperglycemia
To treat underlying diseases
To monitor and assist cardiovascular, pulmonary, renal, and central nervous
system (CNS) function
Rapid and aggressive intravascular volume replacement is always indicated as the first
line of therapy for patients with HHS. Isotonic sodium chloride solution is the fluid of
choice for initial treatment because sodium and water must be replaced in these severely
dehydrated patients.
Standard Care for Dehydration and Altered Mental
Status
Standard care for dehydration and altered mental status is appropriate, including airway
management, IV access, crystalloid fluid replacement, and administration of any
medications routinely given to coma patients.
Fluid resuscitation
Fluid deficits in HHS are large; the fluid deficit of an adult may be 10 L or more.
Infuse enough volume to allow the perfusion of vital organs and the kidneys. A
reasonable goal of treatment is to replace half of the estimated volume deficit in the first
12 hours of therapy. The remainder of the volume deficit may then be replaced over the
second 12-hour period.
A 500-mL bolus of 0.9% isotonic saline is appropriate for nearly all adults who are
clinically dehydrated. Administer 1-2 L of isotonic saline in the first 2 hours. A higher
initial volume may be necessary in patients with severe volume depletion. Slower initial
rates may be appropriate in patients with significant cardiac or renal disease. Caution
should be taken to not correct hypernatremia too quickly, as this could lead to cerebral
edema. As much as 2 L of 0.9% isotonic saline may be infused safely over the first hour
of treatment.
After the initial bolus, some clinicians recommend changing to half-normal saline,
whereas others continue with isotonic saline. Either fluid likely will replenish
intravascular volume and correct hyperosmolarity; a good standard is to switch to halfnormal saline once blood pressure and urine output are adequate.
When the blood glucose concentration, initially checked hourly, reaches 250 mg/dL,
change the infusion to 10% dextrose in 0.9% isotonic saline again. This helps prevent a
precipitous fall of glucose, which may be associated with cerebral edema.
Insulin Therapy for Correction of Hyperglycemia
All patients with HHS require IV insulin therapy; however, immediate treatment with
insulin is contraindicated in the initial management of patients with HHS. The osmotic
pressure that glucose exerts within the vascular space contributes to the maintenance of
circulating volume in these severely dehydrated patients. Institution of insulin therapy
drives glucose, potassium, and water into cells. This results in circulatory collapse if fluid
has not been replaced first.
After the kidneys show evidence of being perfused, initiating insulin therapy is safe. This
is accomplished most effectively in the ICU, where cardiovascular and respiratory
support is available if needed. Infuse insulin separately from other fluids, and do not
interrupt or suspend the infusion of insulin once therapy is started.
The following steps may be used as a guideline for insulin infusion:
•
•
•
•
•
•
•
•
•
Begin a continuous insulin infusion of 0.1 U/kg/h
Monitor blood glucose by means of bedside testing every hour; if glucose levels
are stable for 3 hours, decrease the frequency of testing to every 2 hours
Set the target blood glucose level at 250-300 mg/dL; this target level may be
adjusted downward after the patient is stabilized
For a blood glucose concentration lower than 250 mg/dL, decrease the insulin
infusion rate by 0.5 U/h
For a blood glucose concentration of 250-300 mg/dL, do not change the insulin
infusion rate.
For a blood glucose concentration of 301-350 mg/dL, increase the insulin infusion
rate by 0.5 U/h
For a blood glucose concentration higher than 350 mg/dL, increase the insulin
infusion rate by 1 U/h
Do not discontinue the insulin drip
If the blood glucose concentration decreases by more than 100 mg/dL between
consecutive readings, wait to increase the insulin infusion rate
When the glucose level has been between 200 and 300 mg/dL for at least 1 day and the
patient’s level of consciousness has improved, glycemic control may be tightened. The
recommended level of glycemia for most patients with type 2 diabetes mellitus (DM) is
80-120 mg/dL. This correlates to the hemoglobin A1c value of 7% recommended by the
American Diabetes Association.
Electrolyte Replacement
Profound potassium depletion necessitates careful replacement. With rehydration, the
potassium concentration is diluted. With the institution of insulin therapy, potassium is
driven into cells, exacerbating hypokalemia. A precipitous drop in the potassium
concentration may lead to cardiac arrhythmia.
Potassium may be added to the infusion fluid and should be started at a level of 5 mEq/L
or less. Hypokalemia at the onset of rehydration requires up to 60 mEq/L to correct the
serum potassium concentration. Check the potassium level at least every 4 hours until the
blood glucose concentration is stabilized.