Fluid and Electrolytes - McMaster Faculty of Health Sciences
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Transcript Fluid and Electrolytes - McMaster Faculty of Health Sciences
Fluids and Electrolytes
September 10, 2008
Karen Koo, PGY5
Chief Critical Care Medicine Fellow
Division of Critical Care Medicine
McMaster University, Hamilton ON
Objectives
Major Body Fluid Compartments
Review of physiology of volume regulation
Parenteral Fluid Therapy
Cases of Electrolyte imbalances
Relationship between the volumes of
major fluid compartments
Composition body fluid compartments
Ion
Plasma
(mmol/L)
ICF
(mmol/L)
Na+
143
9
K+
5
135
Ca2+
1,3
<0,8
Mg2+
0.9
25
Cl-
9
HCO3-
103
24
HPO42-
0,4
74
Sulphate-
0,4
19
Protein-
1,14
64
9
Daily Fluid Requirements
Average Adult needs:
H 2O
~ 30-35ml/kg/hr (2-3 liters/day)
Na+
~1
ml/kg/hr
K+
~1
ml/kg/hr
Cl-
~ 1.5
ml/kg/hr
Sources of daily water loss
Urine
1200-1500 ml/d (30ml/hr)
Sweat
200-400 ml/d
Lungs
500ml/d
Feces
100-200 ml/d
Composition of GI Secretions
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)
0
100~2000
140
5
80
0
Ileum
3000
140 (80~150)
5 (2~8)
104 (43~137)
30
Colon
100-9000
60
30
40
0
Pancreas
100-800
140 (113~185)
5 (3~7)
75 (54~95)
115
Bile
50-800
145 (131~164)
5 (3~12)
100 (89~180)
35
Source
Duodenum
* Average concentration: mmol/L
Daily Electrolyte loss
Na+
100 mEq
K+
100 mEq
Cl-
150 mEq
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
Regulation of Fluids
Regulation of Fluids
Renal sympathetic nerves
Renin-angiotensinaldosterone system
Atrial natriuretic peptide
(ANP)
Parenteral Fluid Therapy
Crystalloids
Na+ main osmotically
active particle
useful for volume expansion (mainly
interstitial space)
for maintenance infusion
correction of electrolyte abnormality
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 intravascularly, inadequate for fluid
resuscitation
Colloid Solutions
Contain high molecular weight
substancesdo not readily migrate across
capillary walls
Preparations
- Albumin: 5%, 25%
- Hydoxyethyl starches
ie pentaspan
- Red cell concentrates
- platelets, plasma
Distribution of Parenteral Fluids
Type of Fluid
ECF=1/3 TBW
ICF=2/3TBW
IVF=1/4ECF
ISF=3/4ECF
1000ml D5W
1000ml 2/3:1/3
1000ml R/L or
0.9%NS
500mL
5%albumin
83
139
250
250
417
750
667
444
0
500
0
0
100mL 25%
albumin
500mL
Pentaspan
500
-400
0
500
0
0
1 unit RBC
450
0
0
Composition of Parenteral Fluids
Solutions
Volumes
ECF
Na+
K+
Ca2+
142
4
4
Mg2+
Cl-
HCO3-
Dextrose
mOsm/L
5
103
27
280-310
3
109
28
273
Lactated
Ringer’s
500
130
0.9%
NaCl
500
154
154
308
0.45%
NaCl
500
77
77
154
D5W
500
D5/0.45%
NaCl
500
77
77
513
513
1026
154
310
3% NaCl
50
406
6%
Hetastarc
h
500
154
5%
Albumin
250
130160
<2.5
130160
330
25%
Albumin
100
130160
<2.5
130160
330
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) 130
4
109
28
b) 154
0
154
40
c) 77
0
77
0
e) 513
0
513
0
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
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
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
28% day Kaplan–Meier Estimates Probability
of Survival: normal saline vs 4% albumin
(NEMJ 2004:350 Safe Investigators)
RR of Death among the Patients in the Six
Predefined Subgroups (NEMJ 2004:350 Safe Investigators)
Colloid solutions for fluid resuscitation
(Cochrane Database Syst Rev. 2008)
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= 3.75 95% CI 0.42 to
33.09).
no evidence that one colloid solution is more
effective or safe than any other
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
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?
a)
0.9% NS at 200ml/hr
0.45% NS/D5W at 100ml/hr
D5W at 100ml/hr
Ringer’s Lactate at 50ml/hr
b)
c)
d)
Clinical Cases:
Electrolyte Imbalances
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
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
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
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
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
Case 3
•
What is electrolyte disturbance?
Hyponatremia
•
What are the most likely surgical causes?
Access clinical fluid status
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
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
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)
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
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
Case 6
45M presents with profound weakness in
setting of chronic diarrhea.
Background Alcohol Abuse
P/E is unremarkable
EKG: Prolonged QTc interval
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
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?
The End