96/03/27 Book Reading

Fluid and Electrolyte Management of the Surgical Patient

Intern 9031119

Outline

• Body fluids / Disturbance / Therapy

• Electrolytes abnormalities :Sodium, Potassium, Mgnesium, Calcium, Phosphorus

Body Fluids

• TBW: 50-60% total body weight

• Serum osmolality: 2 Na+ + glucose/18 + BUN/2.8

2/3 ICFK+, Mg++

phosphate, proteins

290mOsm

1/3 ECFNa+

Cl-, HCO3---

310 mOsm

¼ plasma

¾ Interstitial fluid

Daily water loss

Disturbance in Fluid Balance

• Extracellular volume deficit� The most common fluid disorder in surgical P’t� Loss of GI fluid ……

• Extracellular volume excess � iatrogenic, renal dysfunction, CHF, cirrhosis…..

Fluid and Electrolyte therapy:

Parenteral solutions

• Isotonic: L/R, N/S� Replace GI loss, ECF deficits

• 0.45 % NaCl + 5 % Dextrose� Maintenance fluid therapy ( post-op ),

Replace ongoing GI loss� 200 kcal / L

Fluid and Electrolyte therapy:

Alternative Resuscitative Fluids

• Hypertonic saline solution ( 3.5, 5 %) � Severe sodium deficit

• Colloids� effective volume expanders ?!

Hydroxyethylstarch

4000 / 70007000

GelatinsHetastarchDextransAlbumin

Pre-operative Fluid Therapy

Pre-Operative Volume Deficits• Obvious GI loss + poor oral intake• Third space losses • Prompt fluid replacement• Isotonic crystalloid

Maintenance Fluids0-10 Kg 100 ml/kg per day11-20 kg 50 ml/kg per day>20 kg 20 ml/kg per day

• Loss of compensatory mechanism due to anesthesia � hypotension

• Continued third space fluid losses

Intraoperative Fluid Therapy

• Bases on current estimated volume status + ongoing fluid loss

• isotonic fluids � 0.45 % saline + dextrose• potassium : renal function, urine output

Post-Operative Fluid Therapy

Body Fluids

• TBW: 50-60% total body weight

• Serum osmolality: 2 Na+ + glucose/18 + BUN/2.8

2/3 ICFK+, Mg++

phosphate, proteins

290mOsm

1/3 ECFNa+

Cl-, HCO3---

310 mOsm

¼ plasma

¾ Interstitial fluid

Hypernatremia

1. Hypervolemic:

� excess sodium containing fluids, mineralcorticoid…

� urine [Na] > 20 mEq / L, osmolarity > 300 mOsm/L

2. Norvolemic, hypovolemic : water losss

Urine osmolaritymOsm / L

Urine [Na+] mEq / L

>400 mOsm/L < 300-400

< 15 < 20

Non-renal causesRenal causes

Correction of Electrolytes Abnormalities:Hypernatremia

• S/S : rare, unless > 160 mEq / L, CNS effect

• in serum Na: < 1 meq/L/h, < 12 mEq/L/ 24h

• 5% dextrose � avoid overly rapid correction

Hyponatremia

• Sodium depletion or dilution� Dilution: post-op patient : ADH � Depletion: decrease intake, increase loss

• Excess solute: hyperglycemia, mannitol…

• Pseudohyponatremia:

plasma lipid, protein

Serum Osmolality:2 Na + glucose/18 + BUN/2.8

Hyponatremia

Post-OP P’t� ADH

Corrected [Na] Plasma glucose 100 mg/dL� plasma Na 1.6 meQ/L

• S/S does not occur until serum Na < 120 mEq/L• Neurologic symptoms present � 3% N/S, no more than 1 mEq/L/h

(no more than 8 mEq/L in the first 24 hours )

� serum Na >130 mEq/L or improved symptoms• Asymptomatic : � < 0.5 mEq/L� maximal increase: 12 mEq / L / day

Correction of Electrolytes Abnormalities: Hyponatremia

Potassium Abnormalities

N/V, intestinal colic, diarrhea, weakness, fatigue, respiratory failure,

Excesses intakerelease from cellexcretion by kidney

Hyperkalemia

Ileus, constipation, weakness, fatigue, tendon reflex , paralysis, cardicarrest,,

Inadequate intakeexcretion

Magnesiun depletion

Hypokalemia

EKG pattern in Potassium abnormalities

Merck and The Merck Manuals

• U wave• T-wave

flattening• ST changes • Arrythmia

• peak T• flatten P • PR prolong • wide QRS• VF

• Oral repletion: Mild, asymptomatic

• IV repletion :< 10-20 mEq/ L /h ……. no monitor< 40 mEq/ L /h ……… EKG monitor

Correction of Electrolytes Abnormalities: Hypokalemia

Correction of Electrolytes Abnormalities: Hyperkalemia

• Discontinue all exogenous sources • Cation-exchange resin : kayexalate• Glucose + insulin • Bicarbonate• EKG changes:

calcium choride or calcium gluconate (5-10 ml , 10%)

• Dialysis

Calcium Abnormalities

• Total serum calcium is affected by albumin � 0.8 mg / dL in calceium for 1g/dL in albumin

• Ionized fraction � neuromuscular stability

• PH � affect the ionized level ex acidosis � protein binding � ionized calcium

Calcium abnomalities

• Hypercalcemia:

hyperparathyroidism malignancy

• Hypocalcemia:pancreatitis, massive soft tissue infection, malignancy with osteoclastic activity ….

Correction of Electrolytes Abnormalities:

Calcium abnomalities

• Symptonatic hypercalcemia: ( > 12 mg/dL )

Repleting the associated volume deficit Brisk diuresis with normal saline

• Symptomatic Hypocalcemia:

IV 10 % calcium gluconate (� 7-9 mg/dL )correct the associated deficits in Mg+, K++, PH

• Hypermagnesium:withhold exogeneous soursescorrect volume deficitcalcium chloride (5-10 ml) dialysis

• Hypomagnesium� hypocalcemia � persistent hypokalemiaoral or IV , for severe deficit

Correction of Electrolytes Abnormalities

Magnesium abnormalities

Correction of Electrolytes AbnormalitiesPhosphate Abnormalites

• Hyperphosphatemia:phosphate binder, calcium acetate, dialysis

• Hypophosphatemia: oral or IV supplementation

Thanks*^_^*

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