Fluid and

Electrolytes

Management in

Post op patients

Under guidance of Dr.(Prof) Nootan.C.

Presented by Dr.Sonal Dixit

Why fluid therapy in surgical pt

needs special consideration ?

• After surgery modification in normal physiology

of fluid and electrolytes balance.

• - ACUTE STRESS leads to increased

sympathetic stimuli- tachycardia,

vasoconstriction & stress.

• Increased ACTH stimulate adrenal gland

which secretes large amount of hydrocortisone

to fight acute stress and aldosterone which leads

to Na retension and urinary loss of K.

• Increased ADH secretion causes water retension , reduction in U.O to as low as 500 ml on 1st post op day.

• NBM status leads to hypovolemia prior to surgery, pt becomes hypotensive during surgery & anaesthesia.

• Fluid loss

• Surgical stress or direct damage of kidney,brain ,lung , skin or GI tract.

Goal of fluid therapy

• Aim to maintain

• B.P >100/70 mm of Hg

• Pulse rate of less than 120 bpm

• Hourly U.O between 30 and 50 ml

• Normal temperature, warm skin , normal

respiration and sensorium.

When and how long to five post-

op iv fluid ?

• Minor or major surgery?

• Short operative procedure ( no handling of intestine or viscera ) – maintenance i.v fluid to correct deficit due to NBM state. After 4-5 hours oral fluid is restarted & iv fluid is not needed.

• Major surgeries ( handling of intestinal viscera ) – requires post op iv fluid for few days.Afterensuring normal movement of intestine oral fluid intake is restarted.

• Major surgery ( handling of intestinal viscera not done ) Most of OBG surgeries – I.V fluid is required for only 24 to 48 hrs.

Which factors to be considered

before writing post op iv fluid ?

• Age , weight , vital data, hydration status and U.O.

• Nature of surgery, blood loss , nature and vol of fluid

and blood replaced intraoperatively.

• Drain output , fluid lost at operative site.

• Renal status,associated illness ( HT,DM) and

associated electrolytes and acid base disorders, if

any.

• Insensible loss due to atmospheric

temp,pyrexia,hyperventilation etc.

Routine Post Op Fluid for 1st 3

days?

• 1st 24 hrs of surgery- 2 lits D-5 or 1.5 lits

D-5 + 500 ml isotonic saline.

• 2ND post Op day- 2 lit 5% dextrose+ 1 lit of

0.9% saline.

• 3rd post op day – Similar fluid + 40-60 mEq

k per day.

• Guidelines which may require modification

depending upon clinical situation.

Why maintenance I.V fluid on the 1st post op

day has less salt and its total volume is lesser?

Increased ADH and aldosterone secretion –

salt and fluid retention by the kidney .

So as to avoid overloading of either salt or

water , i.v fluid with lesser or even no

sodium and in lesser volume than routine

maintenance need of normal individual is

prescribed.

When on 1st post op day ,saline

containing fluid is preferred?

• Elderly patients with salt losing

nephropathy.

• Head injury or neurosurgical pts.

• Patients on diuretics and mannitol.

• To replace nasogastric aspiration and

drain output.

• In most of the major surgery, saline is

given to replace third space losses.

K is avoided in I.V fluids for 1st 2

post operative day?

• Pt may have oliguria or azotemia.

• Post op trauma release K from intracellular

to extracellular compartment-

hyperkalemia.

• Intra or post op transfusion of stored blood

• Post operative metabolic acidosis shifts

intracellular K extracellularly.

How to infuse IV fluid

postoperatively ?

• Maintenance fluid should be given at a

steady rate over an 18 to 24 hrs period.

• If given over a short period ,renal excretion

of excess salt and water may occur. But as

the normal losses continues over 24 hrs,

body will be deprived of their fluid need

during the remaining period.

Volume Excess

• Blood excess – pulmonary congestion.

• Saline excess- weight gain, periorbital

puffiness, hoarseness or dysnoea on

exertion.

• Hypotonic fluid excess ( 5% dextrose) –

hyponatremia ( mental confusion,

drowsiness or rarely coma or convulsions).

Fluid volume deficit

• Decreased U.O < 30 ml/hr

• Postural hypotension

• Tachycardia

• Diminished skin turgor

• Decreased capillary refill time

• Inc BUN out of proportion to creatinine

TREATMENT

Depends on the type of fluid lost , can be done with isotonic solutions –NS or LR.

Hyponatremia

• Excess ADH- retension of water In excess of sodium.

• Excess 5% dextrose

• Water administration consistently which exceeds water loss.

• Nausea without vomiting, drowsy, weak, confused or gets convulsion.

TREATMENT

Avoid using hypotonic solution.

Avoid excessive use of electrolyte free solutions during the first 2-4 post op days.

Serum Na should be kept between 130-135 mEq/ml

Hypernatremia

• Uncommon

• Excess isotonic saline.

• Diabetes insipidus

• Excess pure water loss in severe

hyperglycemia due to osmotic diuresis.

Treatment

0.45% NaCl – half strength saline

Hypokalemia

• Most common

• Lost through urine or GI.

• Post op infusion of mannitol or diuretics.

• Prolonged administration of potassium free i.v fluids.

• Extreme weakness , muscular hypotonia , paralytic ileus. Pts on digitalis therapy are more prone to develop cardiac arrythmias due to hypokalemia.

Treatment

Daily supplement 60 -100 mEq QD.

Remember –hyperkalemia is more dangerous than hypokalemia.

Hyperkalemia

• Uncommon

• Cardiovascular symptoms- bradyarrhythmias, hypotension , diastolic cardiac arrest.

• ECG changes – wide QRS complex, peaked T waves.

• Treatment

• Inj cal gluconate , inj sod bicarbonate, glucose and insulin , kayexalate ( orally or by retension enema ).

Fluid management in

Hypertension

• Remember that fluid overload can easily lead to pulmonary edema and cardiac failure in hypertensive patient, so ensure that fluid should be administered over strict 24 hrs and not faster.

• Sodium containing fluids will cause water retension and will increase the B.P eventually.

• Strict B.P monitoring should be done on 1st post op day.

• Lasix will drop the b.p , increase the urine output but can cause disturbance in electrolyte levels.

Fluid management in Diabetes

• In diabetic post op patients there are high chances of development of diabetic ketoacidosis.

• Avoid using dextrose on 1st post op day as already due to excess glucocorticoids the level of glucose is on the higher side.

• With DNS insulin should be added i.e neutralizing drip should be prepared. 10 units of human actrapid in 1 lit of DNS is a good option . RBS charting should be done 2 hrly of 1st day , 4 hrly on 2nd – come back to subcutaneous insulin or oral hypogycemic drugs once the patient starts on oral.

What is Sliding Scale?

• RBS hourly.

• 150 to 200 – 4 units

• 201 to 250 – 6 units

• 251 to 300 – 8 units

• And so on …

I.U of human insulin or human actrapid .

Blood transfusionLife saving

Advantage

• Most physiological way to replace blood

loss.

• Corrects hypotension secondary to blood

loss.

• Adequate tissue oxygen.

• Effective than crystalloids and cheaper

than colloids to correct hypotension.

How to estimate intra op blood

loss?

• Weigh sponges before and after use- diff

in grams is eqivalent to ml of blood

absorbed.

+

. Blood in suction bottle

* 1½

= approx blood loss.

How to decide need for B.T?

• Pre op hemoglobin or hematocrit – Oxygen

carrying capacity is unaffected till Hb is as

low as 8 gm/dl & hematocrit is 25%.

• Percentage of blood loss

Total blood vol in adult female is 65 ml/kg.

Loss less than 10% is insignificant.

10%-20%- clinical decision

>20% - 100 % B.T

Eg - 500ml loss in 65 kg female ( total blood

vol in ml = 65* 65 = 3575 ml ) ,the loss

less than 10% of total blood volume, which

is not significant loss and does not require

B.T.

But same 500 ml loss in 20 kg female is

30% of total vol- significant and require

B.T.

Other factors

• Vital data – emergency surgery in

hypotensive pt needs B.T.

• Hydration status

• Old people

• Pts with IHD

How to estimate new Hb after

intra op blood loss?

• Step 1 . Convert vol of blood loss into %

• % reduction of Hb = 1.25 * vol of blood

loss / weight

• Step 2 . Convert % into reduction in gm/dl

• = preop Hb * % of reduction / 100

• Step 3 . Hb status after blood loss

• = pre op hb in gm/dl – reduction in Hb

gm/dl

Example – A 50 kg women with

14gm/dl loses 800 ml .

• New hb status?

% reduction of Hb = 1.25 * 800/50 = 20%

Reduction in gm/dl = 20 * 14/100 = 2.8 gm/dl

Hb status after blood loss = 14-2.8 =11.2 gm/dl.

When not to give B.T?

• Blood loss less than 500 ml in adult with normal preop Hb.

• Loss of 10% of estimated blood vol is well tolerated , such losses are usually replaced with crystalloids like RL or 0.9% saline.

• As a rule blood loss needs to be replaced with 3 times vol of crystalloids.

When to give B.T?

• Blood loss > 20% of blood volume.

• Replacement of blood loss between 10% and 20% is a matter of clinical discretion. If Hb status after loss is expected to be less than 10gm/dl ,B.T is given.

• 500ml to 1000ml – single unit of blood is req.

• B.T is mandatory if Hb falls below 8gm/dl after blood loss.

What is MABL?

• Maximum allowable blood loss- amount of

blood loss, which does not require B.T.

• = preop pt’s hematocrit-25 * estimated

blood volume / preop pt’s hematocrit.

• Lowest acceptable hematocrit value is

25%.

THANK YOU

Treat the patient as a whole,

“Half a sheep is mutton.”