fluid/acid-base HYPER NA (07-29) (1) Flashcards
Mild hyperNa?
146-150
Moderate hyperNa?
151-155
Severe hyperNa?
156 ir daugiau
HyperNa time development?
acute and chronic
48h
HyperNa fluid status?
hypo, eu, hypervolemia
FA. Hyper Na very often symptom?
thirst caused by hypertonicy
uptd. Cognitive dysfunction and symptoms associated with neuronal cell shrinkage?
Altered mental status
Focal neurologic deficits
lethargy, confusion, seizures,
abnormal speech, irritability, nystagmus, myoclonic jerks, muscle spasticity, obtundation, nausea, vomiting
uptd. Dehydration or clinical signs of volume depletion?
orthostatic BP changes, tachycardia, oliguria, dry oral mucosa, abnormal skin turgor, dry axillae, intense thirst
uptd. Other clinical findings?
weight loss, generalized weakness, fever, labored respiration.
uptd. 3 groups of hyperNa symtpms?
1.Cognitive dysfunction
2.Dehydration or clinical signs of volume depletion
3.Other
FA. etiology of hypernatremia? how to determine?
Determines by measuring URINE OSMOLALITY
FA. Determination of etiology.
Urine osmolality > 600? 2
Most likely stems from EXTRARENAL water loss
OR
EXCESS Sodium intake
FA. What are extrarenal loses?
insensible losses, nasogastric tube suction, diarrhea
FA. urine osm > 600. How to detemine whether extrarenal or incr. sodium intake?
by measuring urine sodium through a fractional excretion of sodium
If extrarenal < 1proc.
If sodium gain > 2 proc.
FA. Determination of etiology.
Urine osmolality < 300? what is the most likely cause?
Diabetes insipidus
Central and nephrogenic
FA. Determination of etiology.
Urine osmolality < 300. how to determine whether central or nephogenic DI? test name
DESMOPRESIN CHALLENGE
FA. Determination of etiology.
Urine osmolality < 300. determine whether central or nephogenic DI. desmopressin test results?
Rise in urine osmolality with desmopresin –> Central DI
No rise in urine osmolality –> nephrogenic DI
FA. Determination of etiology.
Urine osmolality has intermediate values: 300 - 600. what may cause?
Often seen in osmotic diuresis or partial DI
FA. EXTRARENAL water loss
osmol and Na fraction?
urine osmol > 600
Fraction < 1proc.
FA. excess sodium intake.
osmol and Na fraction?
urine osmol > 600
Fraction > 2 proc.
FA. Central DI.
osmol and desmopresin test?
urine osmol < 300.
After test - incr. in urine osmolality
FA. Nephorgenic DI.
osmol and desmopresin test?
urine osmol < 300.
After test - NO increase in urine osmolality
FA. Often seen in osmotic diuresis or partial DI. What osmol?
300-600
FA. 6D causes of hyperNa?
Diuresis
Dehydration
Diabetes insipidus
Docs (iatrogenic)
Diarrhea
Disease (kidney, sickle cell)
uptd. 3 mechanisms of hyper Na?
- Excessive water loss (unreplaced) – most common cause, or inadequate water intake
- Water loss into cells;
- Sodium overload.
uptd. 1. water loss (unreplaced)/inadequate intake.
what causes? 4 groups
Skin losses (sweating) - sweat hypotonic to serum
GI losses
Urinary losses (DI both, present with polyuria, osmotic diuresis due to glucose, urea, mannitol)
Hypothalamic lesions impairing thirst or osmoreceptor function (Primary hypodipsia – impaired thirst. Congenital or acquired hypothalamic structural lesions. Reset osmostat syndrome (changed osmolality threshold) in mineralcorticoid excess)
uptd. 2. water loss into cells.
what is the cause and mechanism?
Transient hypernatremia (in which the serum sodium concentration can rise by as much as 10 to 15 mEq/L within a few minutes) can be induced by severe exercise or electroshock-induced seizures, an effect that is mediated by a transient increase in cell osmolality.
Serum Na becomes normal within 5 to 15 minutes after the cessation of exertion or seizure activity.
uptd. 3. sodium overload
causes? 2 main groups
Iatrogenic sodium loading (hypertonic or isotonic saline solutions)
Isotonic - causes net Na gain.
Salt poisoning (mostly in children, considered as abuse, or accidental use of salt instead of sugar in formula), can cause catastrophic hemorrhage from tearing of bridging cerebral veins is possible in the most severe cases of brain shrinking)
uptd. 3. sodium overload
due to isotonic saline. What scenarios?
Uncontrolled diabetes
Severe azotemia
Nasogastric suction - patients often receive isotonic saline to replace fluid losses that have sodium plus potassium concentrations well below that of plasma
Edematous, critically ill patients who have received large volumes of saline and then receive loop diuretic therapy, which impairs renal concentrating ability resulting in inappropriately high water losses.
Scheme internet. HyperNa. Evaluate fluid status. Hypovolemia. What causes belong?
Extrarenal losses
Renal losses
Scheme internet. HyperNa. Evaluate fluid status. Euvolemia What causes belong?
Diabetes insipidus
Scheme internet. HyperNa. Evaluate fluid status. Hypervolemia. What causes belong?
Exogenous Na administration
Extrarenal losses
Renal losses.
what fluid status?
hypovolemia
Diabetes insipidus
fluid status?
Exogenous Na administration
Exogenous Na administration
fluid status?
hypervolemia
FA. treatment according what?
Fluid status
FA. treatment. Hypovolemia with unstable vital signs (aka SYMPTOMATIC)?
isotonic 0,9 proc. NaCl before correcting free water deficits
Use it until patient reaches euvolemia.
then dextrose 5 proc. (UW)
FA. treatment.
How to determine free water deficit?
water deficit =
TBW x ((serum Na/140)-1)
TBWater is ~60 proc. of lean body weight
FA. treatment. determine rate of correction?
If chronic - should be accomplished gradually over 48-72h (=<0,5 mmol/l/h) to prevent neurologic damage secondary to cerebral edema
If acute - the entire water deficit can be corrected within 24h.
FA/UW. treatment. Hypovolemia NO SYMPTOMS?
dextrose 5 proc.
Hypovolemic hyperNa: fluids to restore?
Isotonic saline, 0,45 proc. NaCl, 5 proc. GDW, oral fluids
Euvolemic hypernatremia: fluids?
free water supplementation, 5 proc. GDW
Central DI: DDAVP
Peripheral: treat cause and salt restriction
Hypervolemic hypernatremia: fluids?
D5S + diuretics
dialysis
uptd. treatment. initial regimen. ml per kilo?
Net positive balance of 3 mL of electrolyte-free water per kilogram of lean body weight will lower the serum sodium by approximately 1 mEq/L
uptd. treatment.
Acute hyper Na - rare. In what causes?
Salt poisoning - lower ASAP
In patients being treated for severe hyperglycemia, whose water losses from glycosuria are not adequately replaced.
in patients with vasopressin disorders
uptd. treatment.
Acute hyper Na. Salt poisoning regimen?
Use: hypotonic intravenous fluids or emergency hemodialysis.
5% dextrose in water 6 ml/kg/h. Adverse effect – hyperglycemia –> increased water loss.
uptd. treatment.
Acute hyper Na.
Vasopressin disorders (DI) regimen?
5% dextrose in water, intravenously, initially at a rate of 3 to 6 mL/kg/hour up to a maximum of 666 mL/hour.
The serum sodium and blood glucose should be monitored every one to three hours until the serum sodium is lowered below 145 mEq/L. THEN reduce 1ml/kg/h until reach 140 mmol/l.
The goal is to rapidly lower the serum sodium in the first few hours (by as much as 2 mEq/L per hour) and to restore a normal serum sodium in less than 24 hours.
ALSO these patients need desmopressin therapy
Hyperglycemia may develop with rapid infusions of 5% dextrose, thereby leading to increased water loss from glycosuria. Thus, after several hours of a rapid infusion, either the rate of infusion should be slowed or the fluid should be changed to a 2.5 percent dextrose in water.
.
uptd. treatment.
Acute hyper Na.
Patients with hypernatremia due to correction of hyperglycemia.
No consensus.
If children and < 40 yo - as in chronic (in researches has been detected cerebral edema due to rapid corection)
if > 40 yo - as in acute due to DI
hypernatremia due to correction of hyperglycemia
Because most of these patients are hypovolemic and hyperglycemic, with ongoing losses of sodium and water due to glycosuria, free water is usually administered as 0.45 percent saline at 6 to 12 mL/kg per hour will provide the same amount of electrolyte-free water as 3 to 6 mL/kg per hour of 5 percent dextrose in water (saline preferred than 5% dextrose).
.
Because both serum sodium and serum glucose determine tonicity, we also recommend serial calculations of the “effective” serum osmolality (2 x Serum sodium + Serum glucose in mmol/L) to monitor the course in plasma tonicity.
.
Chronic hypernatremia - if it has been present for longer than 48 hours.
Nearly all patients with hypernatremia will have chronic hypernatremia.
.
uptd. chronic hyper Na.
initial regimen?
5% dextrose in water, intravenously, at a rate of ~ 1.35 mL/kg per hour, up to a maximum of 150 mL/hour), aprox. 100 mL/hour in a 70 kg patient.
if clinically stable and consciousness - can drink peroral fluids or via nasogastric tube
uptd. chronic hyper Na.
goal to lower Na to what level?
Lower the serum Na by approximately 10 mEq/L in 24 hours but to avoid correcting the serum Na by more than 12 mEq/L in 24 hours.
