1. Fluid and Electrolyte Balance during Injury
Zohair Al Aseri. MD. FCEM(UK).FRCPC (EM&CCM) Chairman ,National Emergency Medicine Committee Consultant, ICU Department of Critical Care College of Medicine, King Saud University Medical City. Riyadh, KSA.

2. Fluid and Electrolyte Balance during Injury
Objectives
Understand and inflammatory response to surgery and trauma
Understand normal regulation of fluid balance
Fluid Imbalance In Shock State
Fluid Therapy (Types) & Indication
Electrolyte disturbances in trauma and surgery
Acid base in surgery patients

3. Fluid and Electrolyte Balance during Injury
Water depletion
Pure water depletion is common in surgical practice, and is usually combined with sodium loss.
The most frequent causes are inadequate intake or excessive gastrointestinal losses.

4. Fluid and Electrolyte Balance during Injury
Water excess common in patients who receive large volumes of intravenous 5% dextrose in the early postoperative period. Such patients have an increased extracellular volume and are commonly hyponatraemic.

5. Fluid and Electrolyte Balance during Injury
Water Excess:
Difficult to detect clinically
Patients with water excess usually remain well
Oedema may not be evident until the extracellular volume has increased by more than 4 litres.

6. Fluid and Electrolyte Balance during Injury
Hypernatraemia: Normal sodium levels are in range mmol/l. Hypernatraemia (>145mmol) results from either water or hypotonic fluid loss or sodium gain.

7. Fluid and Electrolyte Balance during Injury
Hypernatraemia:
Water loss is commonly caused by
reduced water intake
vomiting, diarrhea
diuresis, burns
sweating and
insensible losses from the respiratory tract
diabetes insipidus.
Typically associated with hypovolaemia

8. Fluid and Electrolyte Balance during Injury
Hypernatraemia:
Sodium gain is usually caused by excess sodium administration in hypertonic intravenous fluids
Typically associated with hypervolaemia.

9. Fluid and Electrolyte Balance during Injury
Hypovolaemic Hypernatraemia is treated with isotonic crystalloid followed by the more gradual administration of water to correct the relative water deficit. We can use 5%dextrose,1/2 NS or 1/4 NS

10. Fluid and Electrolyte Balance during Injury
Cells, particularly brain cells, adapt to a high sodium concentration in extracellular fluid, and once this adaptation has occurred, rapid correction of severe hypernatraemia can result in a rapid rise in intracellular volume, cerebral oedema, seizures and permanent neurological injury.

11. Fluid and Electrolyte Balance during Injury
Hyponatraemia (Na- < 135mmolfl) can occur with high, low or normal extracellular volume. The commonest cause is the administration of hypotonic intravenous fluids (as intravenous 5% dextrose) is administered in the postoperative period (dilutional hyponatraemia).

12. Fluid and Electrolyte Balance during Injury
Hyponatraemia Other causes include diuretic use and (SIADH) Co-morbidities associated with secondary hyperaldosteronism, such as cirrhosis and congestive cardiac failure.

13. Fluid and Electrolyte Balance during Injury
Sodium deficit This can be calculated as follows: 140- measured sodium x 0.2 x weight in kg where 0.2 refers to the 20% extracellular space which represents the compartment in which sodium is the main cation.

14. Fluid and Electrolyte Balance during Injury
Hyponatraemia Treatment depends on correct identification of the cause: If ECF volume is normal or increased, the most likely cause is excessive intravenous water administration and this will correct spontaneously if water intake is reduced.

15. Fluid and Electrolyte Balance during Injury
Hyponatraemia Although less common in surgical patients, SIADH promotes the renal tubular reabsorption of water independently of sodium concentration, resulting in inappropriately concentrated urine (osmolality> 100m0sm / l) in the face of hypotonic plasma (osmolality< 290m0sm/ l).

16. Fluid and Electrolyte Balance during Injury
Hyponatraemia
The urine osmolality helps to distinguish inappropriate ADH secretion from excessive water administration.
'Spot‘ measurement of urine sodium will be high.

17. Fluid and Electrolyte Balance during Injury
Hyponatraemia
In patients with decreased ECF volume,
hyponatracmia usually indicates combined water and sodium deficiency.
This is most frequently the result of
Diuresis
Diarrhea
Adrenal insufficiency
Treatment by 0.9 sodium chloride

18. Fluid and Electrolyte Balance during Injury
Hyponatraemia severe hyponatraemia (< 120mmol/ l) associated with confusion, seizures and coma.

19. Fluid and Electrolyte Balance during Injury
Hyponatraemia Rapid correction of sodium concentration can precipitate an irreversible demyelinating condition known as central pontine myelinolysis Sodium concentration should not increase by more than 0.5 mmol/h.

20. Fluid and Electrolyte Balance during Injury
Hyponatraemia This can usually be achieved by the cautious administration of isotonic (0.9%) sodium chloride, occasionally combined with the use of a loop diuretic (e.g. furosemide). Hypertonic saline solutions only for sever hyponatremia with CNS manifestation like seizure

22. Fluid and Electrolyte Balance during Injury
Potassium 98% of total body potassium (around 3500mmol) is intracellular serum potassium concentration (normally mmol/ l) is a poor indicator of total body potassium.

23. Fluid and Electrolyte Balance during Injury
Potassium no absolute formula to determine K deficit. When the serum K is < 2.5mmol/ l about mmol of KCL will be needed in a 70kg adult. Serial monitoring of serum K is necessary to prevent overcorrection

24. Fluid and Electrolyte Balance during Injury
Potassium Once the serum K comes above 3.0 mmol /1, K supplements can be reduced. Acidosis reduces Na+/kATpase activity and results in a net efflux of potassium from cells and hyperkalaemia. Conversely, alkalosis results in an influx of potassium into cells and hypokalaemia.

25. Fluid and Electrolyte Balance during Injury
Hyperkalaemia
This is a potentially life-threatening condition.
caused by
exogenous administration of K
release of K from cells (transcellular shift) as a result of tissue damage or changes in the Na / K-ATPase function
impaired renal excretion.

26. Fluid and Electrolyte Balance during Injury
Hyperkalaemia Mild hyperkalaemia (K" < 6mmol/l) is often asymptomatic. High K cause progressive slowing of electrical conduction in the heart and the development of significant cardiac arrhythmias. So ECG is mandatory in all suspected hyperkalaemia

27. Fluid and Electrolyte Balance during Injury
Hyperkalaemia
ECG Finding
Tall 'tented' T-waves in the precordial leads are the earliest
flattening (or loss) of the P waves
prolonged PR interval
widening of the QRS
asystole.

30. Fluid and Electrolyte Balance during Injury
Hyperkalaemia Severe hyperkalaemia (K > 7m mmol/l) requires immediate treatment

31. Treatment of hyperkalaemia

32. Fluid and Electrolyte Balance during Injury
Hypokalaemia common in surgical patients. Dietary intake of k is normally mmol / day. Under normal conditions, the majority of k loss (> 85%) is via the kidneys Maintenance of K balance largely depends on normal renal tubular regulation.

33. Fluid and Electrolyte Balance during Injury
Hypokalaemia
K excretion is increased by
Metabolic alkalosis
Diuresis
Increased aldosterone release
Increased losses from the GI tract.

34. Fluid and Electrolyte Balance during Injury
Hypokalaemia
Diagnostic features
Muscle weakness
Paralytic ileus
Flattening of T waves
Prominent u waves

36. Fluid and Electrolyte Balance during Injury
Hypokalaemia For every 3 K ions that come out from the intracellular compartment, one H and two Na ions are exchanged causing extracellular alkalosis and intracellular acidosis.

37. Fluid and Electrolyte Balance during Injury
Hypokalaemia
Treatment
Oral or NG potassium replacement in mild hypokalaemia.
Severe (K" < 2.5 mmol/1) or symptomatic hypokalaemia requires IV replacement.

38. Fluid and Electrolyte Balance during Injury

39. Fluid and Electrolyte Balance during Injury
Calcium Clinically significant abnormalities in endocrine surgery.

40. Fluid and Electrolyte Balance during Injury
Magnesium
Hypomagnesaemia is common in
restricted oral intake
intra­venous fluids for several days

41. Fluid and Electrolyte Balance during Injury
Magnesium It is frequently associated with other electrolyte abnormalities, notably hypokalaemia, hypocalcaemia and hypophosphataemia.

42. Fluid and Electrolyte Balance during Injury
Hypomagnesaemia associated with arrhythmias (most notably torsades de pointes (polymorphic ventricular tachycardia) and atrial fibrillation) Manifestations of are nonspecific (muscle weakness, muscle cramps, altered mentation, tremors, hyperreflexia and generalized seizures).

43. Fluid and Electrolyte Balance during Injury
Hypomagnesaemia
When hypokalaemia and hypomagnesaemia coexist it may be difficult to correct the former without correcting the latter.

44. Fluid and Electrolyte Balance during Injury
Phosphate Phosphate is a critical component in many biochemical processes such as ATP synthesis, cell signaling and nucleic acid synthesis.

45. Fluid and Electrolyte Balance during Injury
Hypophosphataemia
common in surgical patients
Severe (< 0.4 mmol/1) causes
widespread cell dysfunction,
muscle weakness,
impaired myocardial contractility,
reduced cardiac output
altered sensorium.

46. Fluid and Electrolyte Balance during Injury
Hypophosphataemia most commonly occurs in malnourished and/ or alcoholic patients commencing enteral or parenteral nutrition. Sepsis is another situation in which marked hypophosphataemia can be seen

47. Fluid and Electrolyte Balance during Injury
Hypophosphataemia refeeding syndrome Hypophosphataemia accompanied by fluid retention and an increase in ECF volume To avoid it feeding should be established gradually with measurement and supplementation of serum electrolytes (phosphate, magnesium and potassium).

48. Fluid and Electrolyte Balance during Injury
Hypophosphataemia Treatment Phosphate can be supplemented orally or by slow intravenous infusion.

49. Fluid and Electrolyte Balance during Injury
Acid-base balance Acidosis ('acidaemia' if plasma pH< 7.35) Alkalosis ('alkalaemia' if plasma pH> 7.45). Both acidosis and alkalosis may be respiratory or metabolic in origin.

50. Fluid and Electrolyte Balance during Injury
Acid-base balance
VBG is good,
ABG is more accurate
coupled with measurement of blood lactate concentration

51. Fluid and Electrolyte Balance during Injury

52. Fluid and Electrolyte Balance during Injury

53. Fluid and Electrolyte Balance during Injury
Acid-base balance
Acid-base abnormalities are tackled by the body by means of
blood buffers
respiratory system
kidneys.

54. Fluid and Electrolyte Balance during Injury
Acid-base balance When the cause is metabolic, respiratory compensation is the most rapid (minutes) followed by the buffering systems hours) and kidneys (days).

55. Fluid and Electrolyte Balance during Injury
Acid-base balance Bicarbonate buffer is the most important in the blood (65%) followed by the protein buffers (30%).

56. Fluid and Electrolyte Balance during Injury
Acid-base balance Bicarbonate buffer (buffer is an acid-base combination where the acid is only partially dissociated) moves from left to right or vice versa depending on the addition of or loss of acid load with an aim to keep the HCO3/ H2CO3 ratio at 20:1.

57. Fluid and Electrolyte Balance during Injury
Metabolic acidosis increase in plasma hydrogen ions in conjunction with a decrease in bicarbonate concentration. A rise in plasma hydrogen ion concentratlon stimulates chemoreceptors in the medulla resulting in a compensatory respiratory alkalosis an increase in minute volume and a fall in PaCO2

58. Fluid and Electrolyte Balance during Injury
Metabolic acidosis Causes Endogenous acid (e.g. lactic acid or ketone bodies) referred to as 'increased anion gap acidosis' or Increased loss of bicarbonate (e.g. intestinal fistula, hyperchloraemic acidosis) which leads to 'normal anion gap acidosis'.

59. Fluid and Electrolyte Balance during Injury
Metabolic acidosis Anion gap 12-l5mmol/l. Na - (Cl + HCO3)

60. Fluid and Electrolyte Balance during Injury
Metabolic acidosis In surgery or trauma lactic acidosis is the communist cause

61. Fluid and Electrolyte Balance during Injury
Metabolic acidosis
Base deficit is a measure of the amount of bicarbonate required to correct acidosis and is calculated as follows:
Base deficit=
normal bicarbonate- measured bicarbonate x0.2 x weight in kg.
where 0.2 refers to the extracellular compartment.

62. Fluid and Electrolyte Balance during Injury
Metabolic acidosis Treatment is directed towards restoring circulating blood volume and tissue perfusion. Blood gas analysis should be repeated every 4-6 hours to assess the requirement for further corrections

63. Fluid and Electrolyte Balance during Injury

64. Fluid and Electrolyte Balance during Injury
Metabolic alkalosis A decrease in plasma hydrogen ion concentration and an increase in bicarbonate concentration. A rise in PaCO2 occurs as a consequence of the rise in bicarbonate concentration, resulting in a compensatory respiratory acidosis.

65. Fluid and Electrolyte Balance during Injury
Metabolic alkalosis in surgery Mainly due to hypokalaemia and hypochloraemia. The kidney has an enormous capacity to generate bicarbonate ions and this is stimulated by chloride loss.

66. Fluid and Electrolyte Balance during Injury
Metabolic alkalosis Example Metabolic alkalosis seen following significant (chloride-rich) losses from the GI tract when combined with loss of acid from conditions such as gastric outlet obstruction.

67. Fluid and Electrolyte Balance during Injury
Metabolic alkalosis
Treatment
Adequate fluid replacement
Correction of electrolyte disturbances, notably hypokalaemia and hypochloraemia
Treatment of the primary cause.

68. Fluid and Electrolyte Balance during Injury

69. Fluid and Electrolyte Balance during Injury
Respiratory acidosis common postoperative problem Increased PC02 and plasma bicarbonate concentrations. Hypoventilation
Examples
general anaesthesia
excessive opiate administration

70. Fluid and Electrolyte Balance during Injury
Respiratory acidosis Hypoventilation respiratory acidosis require ventilatory support

71. Fluid and Electrolyte Balance during Injury

72. Fluid and Electrolyte Balance during Injury
Respiratory alkalosis Respiratory alkalosis is caused by excessive excretion of CO2 as a result of hyperventilation. PCO2 and hydrogen ion-concentration decrease. Respiratory alkalosis is rarely chronic and usually does not need specific treatment.

73. Fluid and Electrolyte Balance during Injury

74. Fluid and Electrolyte Balance during Injury
Mixed patterns of acid-base imbalance Mixed patterns of acid-base disturbance are common, particularly in very sick patients.

75. Case 1
39 year old male involved in MVC brought to ED by EMT, he is unconscious, hr 120 bp 80/50, intubated in the scene, what is your immediate action
Take further history
Start him on dextrose 5% with NS
Start him in colloid
Start him in Normal saline

76. Case2
A recovery nurse calling you to see a 70 year old male, 7 hours post appendicictomy, because he is drowsy and unresponsive, his vital signs are normal and oxygen saturation 92% on room air? What is the most likely diagnosis?
Intracranial bleeding
Stroke
Acute renal failure
Respiratory failure

77. Case3
70 year old male, admitted for elective hernia repair, kept NPO and started in D5 ½ normal saline 24 hour ago, his current electrolyte showed k of 5 mmol and Na of 128 mmol What is the most likely diagnosis? DI
SAIDH
Acute renal failure
Iatrogenic hyponatremia

78. Fluid and Electrolyte Balance during Injury
Summary
Understand of The Normal Regulation of Fluid Balance
Fluid Imbalance In Shock State
Early Hemodynamic Optimization
Fluid Therapy (Types) & Indication
Electrolyte disturbances in trauma and surgery
Acid base in surgery patients

79. Thank you ??