1. Fluids and Electrolytes September 10, 2008
Karen Koo, PGY5
Chief Critical Care Medicine Fellow
Division of Critical Care Medicine
McMaster University, Hamilton ON

2. Objectives Major Body Fluid Compartments
Review of physiology of volume regulation
Parenteral Fluid Therapy
Cases of Electrolyte imbalances

3. Relationship between the volumes of major fluid compartments

4. Composition body fluid compartments
Plasma
(mmol/L)
ICF
Na+
143 9 K+ 5
135
Ca2+
1,3
<0,8
Mg2+
0.9 25
Cl-
103
HCO3- 24
HPO42-
0,4 74
Sulphate- 19
Protein-
1,14 64

5. Daily Fluid Requirements
Average Adult needs:
H2O ~ 30-35ml/kg/hr (2-3 liters/day)
Na+ ~ 1 ml/kg/hr
K+ ~ 1 ml/kg/hr
Cl- ~ 1.5 ml/kg/hr

6. Sources of daily water loss
Urine ml/d (30ml/hr)
Sweat ml/d
Lungs 500ml/d
Feces ml/d

7. Composition of GI Secretions
Source
Volume (ml/24h)
Na+* K+
Cl-
HCO3-
Salivary
1500 (500~2000)
10 (2~10)
26 (20~30)
10 (8~18) 30
Stomach
1500 (100~4000)
60 (9~116)
10 (0~32)
130 (8~154)
Duodenum
100~2000
140 5 80
Ileum
3000
140 (80~150)
5 (2~8)
104 (43~137)
Colon 60 40
Pancreas
140 (113~185)
5 (3~7)
75 (54~95)
115
Bile
50-800
145 (131~164)
5 (3~12)
100 (89~180) 35
* Average concentration: mmol/L

8. Daily Electrolyte loss
Na mEq
K mEq
Cl mEq

9. Quiz #1: True or False statements Concerning body fluid compartments:
a) Water constitutes 70% of the total body weight b) Plasma constitutes a quarter of the ECF volume d) Interstitial fluid volume for a 70 kg man is approximately 9 litres e) The ECF/ICF volume ratio is smaller in infants and children than it is in adults
FTTF

10. Regulation of Fluids

11. Regulation of Fluids Renal sympathetic nerves Renin-angiotensin-
aldosterone system
Atrial natriuretic peptide (ANP)

12. Parenteral Fluid Therapy
Crystalloids
Na+  main osmotically
active particle
useful for volume expansion (mainly
interstitial space)
for maintenance infusion
correction of electrolyte abnormality

13. Crystalloids Isotonic crystalloids - Lactated Ringer’s, 0.9% NaCl
- 25% remain intravascularly
Hypertonic saline solutions
- 3% NaCl
Hypotonic solutions
- D5W, 0.45% NaCl
- < 10% remain intra-
vascularly, inadequate for fluid
resuscitation

14. Colloid Solutions Contain high molecular weight
substancesdo not readily migrate across
capillary walls
Preparations
- Albumin: 5%, 25%
- Hydoxyethyl starches
ie pentaspan
- Red cell concentrates
- platelets, plasma

15. Distribution of Parenteral Fluids
Type of Fluid
ECF=1/3 TBW
ICF=2/3TBW
IVF=1/4ECF
ISF=3/4ECF
1000ml D5W 83
250
667
1000ml 2/3:1/3
139
417
444
1000ml R/L or 0.9%NS
750
500mL 5%albumin
500
100mL 25% albumin
-400
500mL Pentaspan
1 unit RBC
450

16. Composition of Parenteral Fluids
Solutions
Volumes
Na+ K+
Ca2+
Mg2+
Cl-
HCO3-
Dextrose
mOsm/L
ECF
142 4 5
103 27
Lactated Ringer’s
500
130 3
109 28
273
0.9% NaCl
154
308
0.45% NaCl 77
D5W
D5/0.45% NaCl 50
406
3% NaCl
513
1026
6% Hetastarch
310
5% Albumin
250
<2.5
330
25% Albumin
100

17. Quiz #2:
70F has small-bowel fistula with output of 1.5L/d. Replacement of daily losses should be handled using the fluid solution that has the following composition:
Na K Cl HCO3 a) b) c) e)

18. Quiz #3:
68M admitted with diagnosis of partial SBO with Hx of Chrons Disease vomits bilious coloured emesis. His is lethargic.
37C, 88/50 mmHg, HR 110, RR 25, SpO2 99 on 2Lnp
JVP flat, chest clear with normal heart sounds
Abd distended & mild epigastric tenderness
Na 130, Cl 108, K 5.1, Cr 110, BUN 10.2
Hg 100, WBC 9.9, Plts 400, INR 1.5, APTT 30

19. Quiz #3:
Your staff asks you to see this patient. What is the most appropriate resusitation fluid:
a) 1 unit of packed RBC
b) 500 ml of Ringers Lactate solution
c) 500ml 5% albumin
d) 500ml Pentaspan
e) 500ml 0.9% normal saline

20. SAFE Study (NEMJ 2004:350 Safe Investigators)
RCT: 4% albumin vs normal saline for intravascular-fluid resuscitation
Primary outcome: 28 day all cause mortality
N = 6997 patients
No significant differences
726 deaths albumin group vs 729 deaths saline group
(RR 0.99; 95% CI 0.91 to 1.09; P=0.87
numbers of days spent in the ICU or in the hospital
days of mechanical ventilation
days of renal-replacement therapy

21. 28% day Kaplan–Meier Estimates Probability of Survival: normal saline vs 4% albumin (NEMJ 2004:350 Safe Investigators)

22. RR of Death among the Patients in the Six Predefined Subgroups (NEMJ 2004:350 Safe Investigators)

23. Colloid solutions for fluid resuscitation (Cochrane Database Syst Rev
Seventy RCTs comparing colloid solutions in critically ill and surgical patients thought to need volume replacement,
N = 4375 participants
Albumin versus hydroxyethyl starch pooled RR 1.14 (95% CI 0.91 to 1.43) for mortality
albumin versus dextran (RR= % CI 0.42 to 33.09).
no evidence that one colloid solution is more effective or safe than any other

24. Calculation of Maintenance Fluids
For a 24 hr period, use 100/50/20 Rule
100ml/kg for first 10kg
50ml/kg for next 10kg
20ml/kg for every kg over 20
For hourly maintenance rate, use 4/2/1 Rule
4ml/kg for first 10kg
2ml/kg for next 10kg
1ml/kg for every kg over 20

25. Quiz #4
55M has been admitted for an elective resection of a pelvic mass. He is NPO for the next 12 hours. He weighs 70kg and has normal renal function. What is the most appropriate iv maintenance rate?
0.9% NS at 200ml/hr
0.45% NS/D5W at 100ml/hr
D5W at 100ml/hr
Ringer’s Lactate at 50ml/hr

26. Clinical Cases: Electrolyte Imbalances

27. Case 1 39M POD2 following ventral hernia repair.
Background: HTN, DM nephropathy
Meds: Ramipril 10mg daily, morphine prn
Patient is weak, c/o paraethesia
Post-op EKG: Sinus bradycardia 40bpm, peaked T waves, depressed ST with prolonged PR, wide QRS
O/E DTR depressed
What is electrolyte disturbance?
What is ddx most likely surgical causes?
What is the acute management strategy?

28. Case 1 What is electrolyte disturbance?  Hyperkalemia
What are the most likely surgical causes?
 RF, Drugs, Acidosis, Tissue injury
blood transfusions
What is the acute management strategy?
 Cardioprotection, shifting, elimination

29. Case 2 70F one week of constipation and vomitting.
Background: DM, Dilated cardiomyopathy, Intestinal fistula
Meds: Insulin, Lasix 80mg bid
Patient c/o weakness, nausea/vomitting and abdominal tenderness
O/E 36.4C 100/60 HR 110, RR12, SpO2 99% r/a
JVP flat, chest clear, normal heart sounds, Abdominal distension, no bowel sounds
EKG: Sinus tachycardia with occasional PVCs, diffuse flattening of T waves, U waves

30. Case 2 What is electrolyte disturbance?  Hypokalemia
What are the most likely surgical causes?
 Drugs (diuretics, steroids, Insulin etc), diarrhea, vomitting, intestinal fistula, NG aspiration, insufficient supplementation
What is the acute management strategy?
 potassium supplementation iv/po

31. Case 3
67M unexplained 30lb wt loss over 6months and hemoptysis presents a GTC seizure
Background: HTN, smoker
Meds: HCTZ 25mg daily
O/E 37C 110/70 HR 88, RR14, SpO2 98%/ra
Lethargic & confused, No focal neuro deficits
JVP 4cmASA, PPP chest clear, normal heart sounds
Abd distended with faint bowel sounds
CXR: speculated LLL nodule

32. Case 3 What is electrolyte disturbance?  Hyponatremia
What are the most likely surgical causes?
 Access clinical fluid status

34. Case 3 – Hyponatremia Management
What is the acute management strategy?
Depends on etiology & chronicity
Be careful! Rate of correction should be <0.5mEq/h, <10mEq/24hr, <18Eq in first 48h
Check lytes frequently during correction
Use 3% NaCl ONLY if severe hyponatremia (Na+ <115) or if dramatically symptomatic with acute onset

35. Case 4
89F admitted with acute pancreatitis on ward for 2 weeks. Progressive confusion in last few days with new tremors
Otherwise healthy, no meds. On TPN.
Net fluid balance 24hrs –4L, u/o 200ml/hr
O/E 36C 110/50 HR 110, RR 10, SpO2 98%r/a
stupourous & clinically hypovolemic
++peripheral edema

36. Case 4 What is electrolyte disturbance?  Hypernatremia
What are the most likely surgical causes?
 Inadequate hydration, diabetes insipitus, diuresis, vomitting/diarrhea, iatrogenic (TPN)
What is the acute management strategy?
 Depends on etiology & chronicity
(D5W or 0.45% normal saline)

37. Case 5
26F with newly diagnosed primary hyperparathyroidism is referred for surgical assessment.
She has had polydipsia, polyuria and constipation and abdominal discomfort.
O/E 37C, 100/80, HR99, RR 14, SpO2100%
Confused, JVP 1cm ASA weak pulses
ABD unremarkable
EKG: short QT, prolonged PR interval

38. Case 5 What is electrolyte disturbance?  Hypercalcemia
What are the most likely causes?
 Hyperparathyroidism, immobility, Pagets, Addisons, Neoplasms, xs Vitamin D, A, Sarcoidosis, Calcium supplementation, thiazides
What is the acute management strategy?
 Volume expansion with NS
 +/- lasix, bisphosphonates, calcitonin, steroids

39. Case 6
45M presents with profound weakness in setting of chronic diarrhea.
Background Alcohol Abuse
P/E is unremarkable
EKG: Prolonged QTc interval

40. Case 6 What are the possible electrolyte disturbances?
 Hypokalemia, hypomagnesiumia, hypophosphtemia, hypernatremia
What is the acute management strategy?
 replace with supplemental magnesium
and potassium phosphate
 fluid therapy

41. Things you don't want to hear during surgery:
5. Damn, there go the lights again...
4. "You know, there's big money in kidneys. Heck, the guy's got two of them."
3. Everybody stand back! I lost my contact lens!
2. This patient has already had some kids, am I correct?
1. Nurse, did this patient sign the organ donor card?
Things you don't want to hear during surgery:
5. Damn, there go the lights again...
4. "You know, there's big money in kidneys. Heck, the guy's got two of them."
3. Everybody stand back! I lost my contact lens!
2. This patient has already had some kids, am I correct?
1. Nurse, did this patient sign the organ donor card?

42. The End 