What is normal fasting glucose? What is considered pre-diabetic/diabetic fasting glucose levels?
Normal: <100 mg/dL
Impaired/diabetic: >126 mg/dL
What is the etiology of DMI? What is it usually caused by?
Due to destruction of islet cells of the pancreas (functions to synthesize insulin)
How do we prepare our Type I DM patients pre-op?
Instruct them not to take short-term insulin.
Instruct them to take 1/3 to 2/3 of their usual intermediate-lasting dose.
Where is insulin produced? At what rate is it made?
How much do we usually secrete a day?
Beta islet cells of the pancreas
1 unit/hr at rest
40-50 U/day (Response to food, vagal stimulation, beta stim, alpha block)
What is the effect of insulin on the moieties in our body?
Increases cellular uptake of glucose and potassium
Stimulates glycogen formation
Inhibits lipolysis and gluconeogenesis
What does surgical stress do to our insulin levels?
It drops our insulin levels.
Release of cortisol, catecholes, and glucagon all lead to hyperglycemia because of this.
Primary difference btwn DM I and DM II is..
How do their onsets differ?
DMI - no insulin production at all
DMII - insulin resistant cells or decreased insulin production (or both)
DMI = early onset
DMII = late onset
HgbA1c is a measure of...
the average level of blood sugar (glucose) over the previous 3 months.
Correlates well with rate of complications
What specific types of insulins would you withhold pre-op in diabetic patients?
Hold metformin (inhibits hepatic gluconeogenesis)
Hold sulfonureas (glyburide, glipizide) bc they increase beta-cell secretion of insulin
If significant interruption of caloric intake is not anticipated, many recommend no change in therapy with DMII patients.
What are some anesthetic considerations about diabetic patients?
Difficult laryngoscopy due to stiff joints
Positioning (more susceptible to ischemia)
Nerve injuries more likely due to poorer perfusion (regional anesthesia)
Increased risk of infection
What is the glucose level threshold at which you would delay surgery? Postpone surgery?
>270 mg/dL = delay surgery until you get a better value
>400 mg/dL postpone surgery until you get pt metabolic state under control
What happens at the onset of surgery to our glucose levels?
In diabetic patients, what glucose levels should we strive for intra-operatively?
Blood sugar will go up due to decreased insulin secretion from stress hormones
Shoot for 150-200 mg/dL (or <180 mg/dL according to Barash)
Note that blood sugar < 110 mg/dL leads to poorer outcomes.
What is DKA?
Diabetic ketoaciosis is a state of exclusive fatty acid breakdown for energy (lipolysis) that leads to ketoacidosis
What subtype of diabetics experience DKA?
Type I DM
Type II DM don't experence DKA because only small amounts of insulin is needed to block lipolyis (and they have it whereas DMI pts dont' have any)
What are physiological effects of DKA?
Dehydration due to osmotic diuresis
Anion-gap metabolic acidosis
If a DM pt experiences mental status changes, what is the first thing you should do?
Check blood sugar to rule out hypoglycemia.
THEN check ABG to rule out DKA or HNKC.
How can we treat DKA intra-op?
Treat with fluid, electrolytes, and insulin.
Add some glucose when BG < 250 to prevent precipitous drop in blood glucose (which would cause hypoglycemia, the opposite end of the spectrum)
Correct N: add 1.5-2.0 mEq/dL every 100 mg/dL BG over 100
Give K (pt may be hyperkalemic, but total body K will be low)
In a pt undergoing DKA, what is usually his/her range of blood glucose level?
Does this correlate with the severity of the acidosis?
300-500 mg/dL range
NO, Degree of hyperglycemia does NOT correlate with severity of acidosis
What is the relationship between glucose and potassium?
K follows Glucose
What is HNKC?
What is it characterized by?
HNKC: Hyperosmolar Non-Ketotic Coma
Characterized by very high BG (>600 mg/dL) with enough insulin to prevent ketosis
What subtype of DM pts can get HNKC?
DMI patients will get DKA instead of HNKC due to lack of any insulin.
Symptoms of HNKC include...
Significant HoTN that leads to lactic acidosis
Cerebral edema --> coma, seizures
Thrombosis secondary to hyovolemia, HoTN, and hyperviscosity of blood (due to extreme dehydration)
How do we treat HNKC?
Treat with a lot of fluids given at a slow rate as well as insulin infusions.
Correct over 24 hours.
What is hypoglycemia?
BG of < 40-50 mg/dL
Diabetis may have symptoms at higher levels due to higher threshold for BG levels
Symptoms of hypoglycemia include..
**Almost impossible to diagnose in unconscious pt
How can we treat hypoglycemia?
25g IV dextrose
1 mg IM glucagon
Why do renal patients often have high blood glucose levels?
Insulin is excreted through your kidneys so renal pts have slow release of insulin into the bloodstream
When you are administering insulin through plastic tubing, what do you need to remember?
It gets stuck to the plastic! Waste 20 cc's!
What are carcinoids?
Slow growing tumors that are often asymptomatic for a long period of time.
The majority of all carcinoid tumors are found in the _______ , _______,and _______.
bronchus, jejunum, colon
Carcinoid syndrome occurs in X% of carcinoid tumors.
X = 20
What are the signs of Carcinoid Syndrome?
Acute onset of:
What is Carcinoid Crisis?
What are the signs of it?
A more severe condition of Carcinoid Syndrome that can be fatal if left untreated.
Signs of Carcinoid Syndrome but more severe in addition to:
What causes Carcinoid Syndrome?
Carcinoid tumor causes release of serotonin, histamine, bradykinin, epi, NE, kallikrein
How can we treat Carconid Synrome/Crisis?
Administer somatostatin/octreotide to reduce release of vasoactive products.
Drugs to avoid in pts with Carcinoid Syndrome:
HA releasing drugs