Fluids, Elect, Acid Base Lecture

8/3/2019 Fluids, Elect, Acid Base Lecture

1/109


2/109

4/28/12

INSTRUCTIONAL LEARNING OBJECTIVES

GENERAL OBJECTIVE:

At the end of the course, the student must be ableto know the basic principles in the recognition andmanagement of the fluids and electrolyte problems

of the surgical patient.

SPECIFIC OBJECTIVES:

1. At the end of the course, the student must be able

to:2. Define the different body fluid compartments as to

its:1. Normal distribution2.

Composition3. Identify the different avenues of normal fluid loss


3/109

4/28/12

5. Recognize the three main categories of body fluidchanges as to its:

1.

Etiology2. Pathophysiology3. Clinical manifestations4. Management

6. Identify specific electrolyte abnormalities

associated with body fluid changes as to its:1. Etiology2. Pathophysiology3. Clinical manifestations4.

Management7. Recognize acid-base disorders associated with

body fluid changes as to its:1. Etiology2. Pathophysiology3. Clinical manifestations


4/109

4/28/12

Anatomy of Body Fluids andElectrolytesTotal Body Water = 60% of

total body weight


5/109


6/109

4/28/12

Anatomy of Body Fluids andElectrolytes


7/1094/28/12



8/1094/28/12


Total body water

Affected by age and lean body mass

Proportion relative to body weight ishigher in infants and children (max. of75-80% of total body weight in newbornis water)

Lean person has more water; obesepersons has less water


9/1094/28/12


AGE MALE FEMALE

NEWBORN 75 80 75 - 80

10 18 years old 59 57

19 40 years old 61 51

41 60 years old 55 47

> 60 years old 52 46

Percentage of Total Body Water in Relation to Ageand Sex


10/109

4/28/12

Water Exchange: Normal exchangeof fluids and electrolytes

Daily water requirement: 2000 2500 ml

About 1500 ml taken by mouth;

remaining extracted form solid foods

Rule of thumb: 30 ml / kg BW / 24hours

Daily Water and Salt Losses:INSENSIBLE

600 1000 ml / day

mainly from the skin (perspiration) and


11/109

4/28/12

Daily electrolyte needs:

Sodium: 5 125 meq

Potassium: 40 100 meq

Rule of thumb:

K and Na / 24 hours = 1 meq/ kg BW

60 70 meq / day for each

Requirements for other electrolytesnormally supplied by daily food intake.



12/109

4/28/12



13/109

4/28/12

Fluid requirements

typically 35 mL/kg/day

insensible loss = 700 mL/day or 0.2cc/kg/day for every 1 C > 37

1-10 kg = 100 mL/kg/day {4mL/kg/hr}

11-20 kg = 50 mL/kg/day {2mL/kg/hr}

> 21 kg = 20 mL/kg/day {1mL/kg/hr}Trick for hourly maintenance = 40 + weight

(kg)


14/109

4/28/12

Daily requirements for electrolytes

Sodium: 1-2 mEq/kg/d

Potassium: 0.5-1 mEq/kg/d

Calcium: 800 - 1200 mg/d

Magnesium: 300 - 400 mg/d

Phosphorus: 800 - 1200 mg/d


15/109

4/28/12

Three Main Categories of Body FluidChanges

VOLUME CHANGESWater or isotonic salt solution gained or

loss

Water deficit or water excess

CONCENTRATION CHANGES

Changes in the concentration of

osmotically active particlesMainly involved sodium with

accompanying changes in osmolality

Hypernatremia or hyponatremia


16/109

4/28/12

VOLUME CHANGES

VOLUME DEFICIT or HYPOVOLEMIAVOLUME EXCESS or HYPERVOLEMIA

Primarily an extracellular fluid (ECF)

compartment phenomenonDiagnosis mainly clinical

History and Physical Examination; clinicalmanifestations

Laboratory examination indirect evidence

Serum Sodium concentrationindependent of ECF volume status


17/109

4/28/12

VOLUME DISTURBANCES


18/109

4/28/12

VOLUME DEFICIT (HYPOVOLEMIA)

Most common fluid disorder insurgical patientspure water loss (simplest form)

Usually NO significant concentrationchanges


19/109

4/28/12

Volume Deficit: Common Causes

External lossesGIT losses vomiting, NGT suctioning,diarrhea, intestinal fistulas

Hemorrhage/bleeding

Internal losses

Sequestration

Soft-tissue injuries/ infections

Intestinal obstruction

Intra-abdominal and retroperitoneal

inflammatory process


20/109

4/28/12

Volume deficit: gastrointestinallosses


21/109

4/28/12

Volume Deficit:Pathophysiology/Clinical Manifestations

Main defect: Decreased ECF watervolume

CNS and CVS effects

CNS effects:

Due to resulting hypernatremia

Restlessness to delirium

CVS effects:

Hypotension and tachycardia

Decreased skin turgor and dry mucuous


22/109

4/28/12

Volume Deficit:Laboratory/Management

Laboratory tests:

Hemoconcentration = inc. hematocrit

Renal insufficiency = elevated BUN &creatinine

Management:

Volume replacementCrystalloid

Colloidal solutions / plasma expanders

Blood


23/109

4/28/12

Volume and Electrolyte Loss

Combined water and electrolyte loss(sodium)

Usually GI losses NGT losses, entericfistulas, enterostomies, diarrheas

Other causes excess diuretics, adrenalinsufficiencies, profuse sweating, burns,body fluid sequestration

Diagnosis:Mainly by history and physical

examination

Clinical manifestations similar to purevolume deficit


24/109

4/28/12

Classification: Hypovolemia/Hemorrhage

Water Loss Hemorrhage

MILD 4% of TBW CLASS I 15% of blood

volumeMODERATE 6% of TBW CLASS II 15 30% of

bloodvolume

SEVERE 8% of TBW CLASS III 30 40% of blood

volume

SHOCK > 8% of

TBW

CLASS IV > 40% of

blood

Blood volume = 7.5% of total bodyweight (approx. 5.0 L)


25/109

4/28/12

Diagnostics: Volume deficit

CBC hemoglobin, hematocrit

BUN, Creatinine

Chest radiographs

Urinalysis

Central Venous Pressure; arterialcatheterization and monitoring

Urine Output

Arterial Blood Gasses

Serum Electrolytes


26/109

4/28/12

Management: Volume Deficit

Fluid and electrolyte resuscitationIntravenous replacement

Intravenous maintenance

Appropriate choice of fluids

CRYSTALOIDS

Plain and Dextrose containing solutions

(eg. D5LRS)

COLLOIDAL SOLUTIONS

Starch containing solutions; dextran

BLOOD AND BLOOD COMPONENTS


27/109

4/28/12

Practical replacement strategies

Sweat: D5NS + 5 mEq KCl/L

Gastric: D5NS + 20 mEq KCl/L

Biliary/pancreatic: LRSmall Bowel: LR

Colon: LR

3rd space losses: LR


28/109

4/28/12

Resuscitation

Crystalloids

Replace blood loss at a 3:1 ratio

Initial bolus 1-2 liters, usually normalsaline

If they have transient response, giveadditional fluids. Once 3-4 liters ofcrystalloid has been given considerblood.


29/109

4/28/12

Indicators of successfulresuscitation

PULSE 100 - 120 bpm

URINARY OUTPUT

CHILDREN = 1.0 ml/kg/hrADULT = 0.5 ml/kg/hr

Clearance of lactate

Resolution of base deficit

BLOOD PRESSURE POOR INDICATOR


30/109

4/28/12

VOLUME EXCESS (HYPERVOLEMIA)

Generally iatrogenic in surgicalpatients

Renal insufficiency

Increase or excess in extracellularfluid volume compartment

Etiology:

Parenteral overhydrationFluid retaining conditions (cardiac or

renal)

Mobilization of previouslyse uestered fluid


31/109

4/28/12

Clinical manifestations:hypervolemia

Weight gain

Pedal / sacral edema

Pulmonary rales and wheezes

Elevated jugular venous pressure(JVP)

Elevated CVP or PCWP

Seizures, muscle twitching (increaseICP)


32/109

4/28/12

Laboratory diagnosis: hypervolemia

Decreased hematocrit

Decreased albumin

Decreased serum sodiumLaboratory manifestations of dilution

effects

Chest radiograph - congestion


33/109

4/28/12

Management: hypervolemia

Water restriction (1500 ml/day)

Diuretics

Sodium restrictions

Albumin infusion

Supportive care cardiac, pulmonary,

renal


34/109

4/28/12

CONCENTRATION CHANGES

Changes in the concentration ofosmotically active particles in thebody fluid compartments

Mainly changes in sodium ionconcentration in the ECFcompartment

May be related to blood glucoseconcentration

HYPONATREMIA or HYPERNATREMIA


35/109

4/28/12

HYPONATREMIA

Low or decreased sodiumconcentration

Dilutional or overhydration especiallyin surgical patients

Hyperglycemia

Conditions that expands plasmavolume


36/109

4/28/12

HYPONATREMIA


37/109

4/28/12

HYPONATREMIA

Pathophysiology/ClinicalManifestations:

Acute hyponatremia

CNS ManifestationsBrain edema; increased intracranial

pressure

Seizures, muscle twitching

Increased deep tendon reflex

Hypertension

Tissue signs of water excess


38/109

4/28/12

HYPONATREMIA

Hyponatremia becomes symptomaticif the serum sodium level becomes 12 mg/ dL

(critical: 16 20)

Bones

Moans

Abdominal groans

Psychic overtonesNausea, vomiting, anorexia

Constipation, polyuria

Confusion, lethargy


84/109

4/28/12

Hypercalcemia

Management:Acute crisis must be managed urgently

Hydration; rapid ECF volume repletion to

lower serum calcium by dilutionLoop diuretics furosemide

Mithramycin intravenously

HemodialysisCalcitonin

Parathyroidectomy (if due to

hyperparathyroidism)


85/109

4/28/12

MAGNESSIUM ABNORMALITIES

Magnessium ion needed in mostenzymatic systems and depletionmay lead to neuromuscular and CNS

hyperactivity


86/109

4/28/12

MAGNESSIUM DEFFICIENCY

Etiology:Complication of malnutrition

Starvation

Malabsorption syndromes

Acute pancreatitis

Diabetic ketoacidosis

GI fluid losses

Prolonged parenteral nutrition andhyperalimentation

Primary aldosteronism


87/109

4/28/12

Magnessium deficiency

Clinical manifestations:

Diagnosis based on high index ofsuspicion clinical and laboratory

Similar to calcium deficiency hyperreflexia, muscle tremors, andtetany with Chvosteks sign

Delirium and convulsionsCardiac arrhythmias


88/109

4/28/12

Magnessium deficiency

Management:

Magnessium replacement : parenteraladministration of Mg sulfate or Mg

Chloride solutions

Check renal function

Monitor cardiac activity, blood pressure

and respiration when giving Mg sulfate


89/109

4/28/12

MAGNESSIUM EXCESS

Etiology:

Renal failure

Antacid overuseHypothyroidism

Adrenal insufficieny


90/109

4/28/12

Magnessium excess


Nausea and vomiting

WeaknessMental status changes

Hyper-reflexia

Hyperventilation


91/109

4/28/12

Magnessium excess

Management:

Remove or discontinue possible externalsources

IV calcium gluconate for emergencycases

Dialysis in renal failure


92/109

4/28/12

Electrolyte replacement therapy


93/109

4/28/12

Electrolyte replacement therapyprotocol

Electrolyte replacement therapy


94/109

4/28/12

Electrolyte replacement therapyprotocol

h h


95/109

4/28/12

Phosphate

HYPOPHOSPHATEMIAEtiology:

TPN nutrition

DM ketoacidosisMalabsorption

Alcoholism

Acute renal tubular necrosisStarvation

Prolonged alkalosis

h h


96/109

4/28/12

Phosphate

HYPOPHOSPHATEMIA


Myocardial depression

Anorexia

Bone pain

Weakness

Rhabdomyolysis

CNS changes

Management:

Parenteral replacement

Ph h


97/109

4/28/12

Phosphate

HYPERPHOSPHATEMIA

Etiology:

Renal insufficiency

HypoparathyroidismCatabolism

Vit D metabolites

May produce metastatic calcificationManagement:

Restrict source

Phosphate-binding antacids

Zi


98/109

4/28/12

Zinc

Enzyme activator; 1 2 gm in thewhole body

Concentrated in the brain, pancreas,liver, kidney, etc

Adjunct in wound healing

S / S of zinc deficiency:

DiarrheaDermatitis

Depression

TX: zinc sulfate tablet at 3 6 mg /


99/109

4/28/12


100/109

4/28/12

Planning daily fluids and electrolyte


101/109

4/28/12

Planning daily fluids and electrolyterequirements

VOLUME OF WATER (replacement ofacute and ongoing loss)

TONICITY or CONCENTRATION

SPECFIC ELECTROLYTES

ACID-BASE BALANCE

CALORIC INTAKE

FOR Surgical patients:


102/109

4/28/12

Click to edit Master subtitle style

THANK YOU


103/109

4/28/12


104/109

4/28/12


105/109

4/28/12


106/109

4/28/12


107/109

4/28/12


108/109

4/28/12


109/109

Fluids, Elect, Acid Base Lecture

Documents

Transcript of Fluids, Elect, Acid Base Lecture