Fluid, glucose and Electrolyte Management for the Pediatric

Surgical Patients

Dr Mohamad Ahangar DavoodiPediatric EndocrinologistDepartment of Pediatric, Arak University of Medical Sciences

The Management of Postoperative Diabetes Insipidus

Brain trauma

• Trauma to the base of the brain and neurosurgical intervention in the region of the hypothalamus or pituitary are common causes of central DI.

• Permanent diabetes insipidus can occur after seemingly minor trauma.

• Approximately one-half of patients with fractures of the sellaturcica will develop permanent diabetes insipidus(may be delayed as long as 1 month following).

• Diabetes insipidus is never associated with cranial irradiation of the hypothalamicpituitary region.

Cause of polyuria after surgery

• postsurgical central DI or diuresis of fluids given during surgery:

• In both cases, the urine may be very dilute and of high volume, exceeding 200 mL/m2/h.

• diuresis of fluids given during surgery; serum osmolality will be normal.

• postoperative central diabetes insipidus; serum sodium of greater than 145 mEq/L, urine output of greater than 4mL/kg/h, plasma osmolarity above 300 mOsm/kg H2O and relatively hypotonicurine.

The triphasic response following surgery

• Initial phase of transient DI, lasting 12-48 hr.(local edema )

• 2nd phase of syndrome of inappropriate antidiuretic hormone secretion (SIADH), lasting up to 10 days.(unregulated vasopressin release from dying neurons)

• permanent DI. (more than 90% of the neurons have been destroyed)

cortisol deficiency

• In patients with coexisting vasopressin and cortisol deficits (in combined anterior and posterior hypopituitarism, following neurosurgical treatment of craniopharyngioma), symptoms of diabetes insipidus may be masked because:

• cortisol deficiency may cause decreased free water clearance by stimulating a nitric oxide-mediated pathway.

central DI may be treated solely with high levels of fluid intake, without vasopressin:

1) Infants

2) DI post neurosurgery

Neurosurgery in children

• In the acute postoperative management of central diabetes insipidus occurring after neurosurgery in children, vasopressin therapy may be successfully used, but extreme caution must be exerted with its use.

• While under the full antidiuretic effect of vasopressin, a patient will have a urine osmolality of approximately 1000 mOsm/kg and become hyponatremic.

• fluid intake of greater than 1 L/m2/day (two-thirds of the normal maintenance fluid requirement) will result in hyponatremia.

• Vasopressin therapy will mask the emergence of the SIAD phase

Manage acute postoperative diabetes insipidus in young children

• 1) It uses fluids alone and avoids the use of vasopressin:

• This method consists of matching input and output hourly using between 1 and 3 L/m2/day (40–120 mL/m2/h). If IV therapy is used, a basal 40 mL/m2/h should be given as 5% dextrose.

• (D5) in one-fourth normal saline (normal saline ¼ 0.9% sodium chloride) and the remainder, depending on the urine output, as 5% dextrose in water. Potassium chloride (40 mEq/L) may be added if oral intake is to be delayed for several days.

• this fluid management protocol prevents any chance of hyponatremia

Example

in a child with a surface area of 1 m2 (approximately 30 kg), the basal infusion rate would be 40 mL/h of 5% dextrose in one-fourth normal saline. For an hourly urine output of 60 mL, an additional 20 mL/h 5% dextrose would be given, for a total infusion rate of 60 mL/h. For urine outputs above 120 mL/h, the total infusion rate would be 120 mL/h. In the presence of diabetes insipidus, this will result in a serum sodium in the 150 mEq/L range and a mildly volume contracted state, which will allow one to assess both thirst sensation, as well as the return of normal vasopressin function or the emergence of SIAD

Manage acute postoperative diabetes insipidus in young children

2) vasopressin for post neurosurgical :

• Patients treated with vasopressin for post neurosurgical diabetes insipidus should be switched from IV to oral fluid intake at the earliestopportunity, because thirst sensation, if intact, will help regulate blood osmolality, as discussed.

• With the concomitant absence of vasopressin secretion and thirst, the clinician must perform administration fluids and an antidiuretic agent (with utmost care).

vasopressin for post neurosurgical

• starts with the child receiving an IV infusion of normal saline at two-thirds maintenance or 1 L/m2/day.

• IV infusion of aqueous vasopressin begins at 0.5 mU/kg/h, with no change in IV fluid administration. The dose of vasopressin is titrated upward in 0.5 mU/kg/h increments to establish a urine output rate of less than 2 mL/kg/h at approximately 10-minute intervals.

• additional normal saline, or equivalent volume expanding solutions, given only to replace ongoing blood loss or to maintain hemodynamic stability.

vasopressin for post neurosurgical

• Either the patient can be put into a persistent antidiuretic state, with dDAVP or vasopressin, and fluid strictly limited to 1 L/m2/day, or the patient can be given intermittent dDAVP with clear urinary “breakthrough” between doses, and a fixed amount of fluid empirically determined to result in normal blood electrolyte concentrations.

children with central DI under surgery

• Germinomas and pinealomas typically arise in this region and are among the most common primary brain tumors associated with DI. Germinomas can be very small and undetectable by MRI(following by serial MRI scans) and often secreted ; α-fetoprotein and β-human chorionic gonadotropin.

• Craniopharyngiomas and optic gliomas can also cause central DI when they are very large.

children with central DI under surgery

• Evidence suggests that perioperative use of IV vasopressin (long-acting vasopressin is withheld or reduced immediately before surgery) in children with central DI may be the treatment modality of choice (is initiated and titrated).

• If continuous vasopressin is administered, fluid intake must be limited to 1 L/m2/day or two-thirds maintenance fluid administration.

Postoperatively management

• intensive care unit monitoring.

• with frequent assessment of electrolytes (hourly initially), urine output and osmolarity/specific gravity, and vital signs.

• Postneurosurgical patients treated with vasopressin infusion should be switched from intravenous to oral fluids as soon as possible to allow thirst sensation, if intact, to help regulate osmolality

Postoperatively management

Human milk is best for this purpose (75 mOsm/kg H2O), whereas cow’s milk is worst (230 mOsm/kg H2O). The Similac PM 60/40 formula has a renal solute load of 92 mOsm/kg H2O. In addition, supplementation free water may be needed, depending on the severity of the diabetes insipidus.Options, such as 20 to 30 mL of supplemental free water for every 120 to 160 mL of formula, or dilution of the formula with free water have been used.Chronically thirsty infants; Alternatively, thiazide (chlorothiazide, 5–10mg/kg/dose), twice or thrice daily, and/or amiloride diuretics may be added to facilitate renal proximal tubular sodium and water reabsorptionMore recently, parenteral desmopressin(4 mcg/mL)(0.02–0.08 mcg/dose given once or twice daily) has been administered subcutaneously in infants with good results,although this is not approved by the FDA.

Antidiuretic Drugs Classification

• dDAVP is also available as a nasal spray in the same concentration, with each spray delivering 10 mcg (0.1 mL).

• Oral dDAVP in doses of 25 to 300 mcg every 8 to 12 hours is reported to be highly effective and safe in children.

• Lysine vasopressin (Diapid) nasal spray (50 units/mL) may be used if a duration less than that of dDAVP is desired. One spray delivers 2 units (0.04 mL).

• IV dDAVP (desmopressin) should not be used in the acute management of postoperative central diabetes insipidus, for it offers no advantage over vasopressin, and its long half-life (8–12 hours) compared with that of vasopressin (5–10 minutes).

Vasopressin side effects

• Vasopressin concentrations >1,000 pg/mL should be avoided because they can cause:

cutaneous necrosis, rhabdomyolysis, cardiac rhythm disturbances, and hypertension.

• bisphosphonate or other therapies designed to prevent bone loss may be of long-term benefit in the treatment of diabetes insipidus.

The Management of patients with T1DM During Surgery

Management objectives during surgery

• prevention of : hypoglycemia, excessive loss of fluids, and ketosis during anesthesia.

• management objectives during major elective or emergency surgery is to use IV infusions of glucose and insulin during the perioperative period.

Hyperglycemic preoperatively

• hyperglycemic preoperatively (serum glucose > 250 mg/dL), it is advisable to check for ketones prior to starting surgery.

• If significant ketosis is identified, surgery should be delayed (if possible) until the ketosis can be treated and resolved.

• Serum glucose levels should be followed every hour operatively and peri-operatively.

Basal insulin preoperative

• The nighttime dose of glargine or detemir insulin may provide sufficient basal insulin coverage for surgery in patients.

• A reduction in the glargine or detemir dose by 20% to 30% on the night before surgery should be considered in patients who have had a tendency to low prebreakfast plasma glucose levels.

• If NPH or Lente is used, one half of the morning dose is given before surgery.

Surgical emergencies

• rehydration and metabolic balance should be restored before the operation.

• One unit of regular insulin for every 2 to 4 g of exogenousglucose may be required because of elevated circulating concentrations of stress hormones or in insulin-resistant obese diabetic patients.

• The blood glucose concentration should be monitored at periodic intervals before, during, and after surgery.

Elective major operations

• should be performed first thing in the morning, and the glucose and insulin infusions should be started 2 hours or more before proceeding to the operating room.

• For elective surgeries; 1 unit of regular insulin is infused intravenously for each 4 to 6 g of administered glucose.

Surgery of short duration

• minor surgery :less than 2 hours, with/without sedation or anesthesia, able to eat by the next meal (within 2-4 hours): endoscopic biopsies, MRI scanning or insertion of grommets.

• on the morning of surgery, half of the usual morning dose of long-acting insulin is administered subcutaneously.

• the usual dose of rapid-acting insulin is omitted unless needed to correct hyperglycemia, and a maintenance IV infusion of the electrolyte and glucose solution is initiated if needed.

Insulin pump therapy

• in patients on insulin pump therapy who are undergoing shortprocedures, the CSII can be continued at the usual or slightly reduced overnight basal rate.

• Insulin pump-treated patients can also be maintained on CSII for major procedures, as long as the integrity of the infusion and infusion site is ensured.

• hyperglycemia can be corrected using the standard home ISF

IV Insulin drip during surgery

• IV insulin is typically started at a dose of 0.03 units/kg/hour for patients who are euglycemic at the time of surgery.

• For elective surgeries; 1 unit of regular insulin is infused intravenously for each 4 to 6 g of administered glucose.

• For surgical emergencies: 1 unit of regular insulin for every 2 to 4 g of exogenous glucose

• Concentrations of 120 to 150 mg/dL should be the goal.• Glycemic and metabolic goals for surgery (ISPAD)• in a range of 5 – 10 mmol/l (90 – 180 mg/dl)

Rate of insulin administration

Fluid therapy during surgery

• An infusion of 5% glucose and 0.45% or 0.9% saline solution with 20 mEq/L of potassium acetate is given at 1.5 times maintenance rate.

• If BG <70 mg/dl give bolus of IV 10% Dextrose 1-2ml/kg; recheck BG 15 minutes later and repeat if necessary.

• If still 70 mg/dl, stop IV insulin for 15 min and recheck and discuss with diabetes team.

Fluid therapy during surgery

• The rate at which IV fluids:1) maintenance 2) losses during surgery 3) other fluid deficits

• The IV insulin and glucose infusions can be continued until the patient is awake and capable of taking regular meals.

Thank you