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Midterm Material
Fluid and Electrolyte Balance
 Role of body fluid
o Maintain blood volume
o Transport material to and from cells
o Assist digestion through hydrolysis of foods
o Regulate body temperature
o Aqueous medium for cellular metabolism
o Medium for excretion of waste
 Fluid compartments
o Intracellular: 40%
o Extracellular: 20%
 Interstitial Fluid: 15%
 Plasma: 5%
 Water in body
o Males: 55-60%
o Females: 50-55%
o Children: 75-80%
 Second spacing: excess accumulation in any of the usual fluid compartments ECF (plasma, ISF), or ICF
o Edema: 2nd spacing in ISF (most common type of 2 nd spacing)
 Spacing between ISF and plasma maintained by
o Hydrostatic pressure (capillary and interstitial)
o Oncotic pressure (plasma and interstitial)
o Osmotic pressure
 Shifts of plasma to ISF
o Increased venous hydrostatic pressure
o Decreased plasma osmotic/oncotic pressure
o Abnormal accumulation of abdominal fluids (ascites)
 Shifts of ISF to plasma
o Increased interstitial hydrostatic pressure
o Increased plasma osmotic pressure (infusion of hyperosmolar solution – D10W, D5NS)
o Increased oncotic pressures (high protein intake with TPN)
 Third spacing: accumulation of fluid in areas that normally have no fluid or only a minimum amount of fluid
(peritoneal cavity, scrotum, pleural space, pericardium)
o Fluid is unavailable or “trapped” for functional use and is not easily exchanged with the ECF
o Pericardial effusion: pericardiocentesis or pericardial tap; cariac needle aspiration to remove fluid
o Ascitic fluid: abdominal paracentesis
 Average fluid gains
o Water from oxidation: 300mL
o Fluid intake: 1200mL
o Fluid in solids: 1000mL
o Total gain: 2500mL
 Average fluid output
o Urine: 1500mL
o Insensible (skin, lungs): 900mL
o Feces: 100mL
o Total loss: 2500mL
 Maintenance fluid requirements (children)
o 1-10kg: 100mL/kg/day
o 10-20kg: 1000mL + 50mL/kg for each kg above 10kg
o Over 20kg: 1500mL + 20mL/kg for each kg above 20kg
o Another way to calculate: Ex. adult 80kg: (80kg x 30) – (80kg x 40) = 2400mL – 3200mL
o Temperature: for every 1 degree increase above 38.5, 15% increased fluid requirement
 Extracellular fluid: transcellular compartment
o Gastric juices: 8L produced/day
 Saliva: 1500mL
 Gastric: 2500mL
 Intestinal: 2000mL
 Pancreatic: 1500mL
 Bile: 500mL
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Cerebrospinal fluid, occhlear fluid, intraocular fluid, pleural/pericardial/peritoneal/synovial fluids, urine in
tubules and bladder
ADH and oxytocin produced in neurosecretory cells in hypothalamus
When appropriate, ADH and oxytocin are secreted from axon endings into bloodstream
Hyperosmolar imbalance
o Na+ gain > H2O gain
o H2O loss > Na+ loss
Hypoosmolar imbalance
o Na+ loss > H2O loss
o H2O gain > Na+ gain
Serum osmolality
o 2 (Na+) + glucose + urea nitrogen = 285-295mmol/L
Aldosterone: mineralcorticoid
o Produced by adrenal cortex in response to 4 things
 Stress (via ACTH)
 Reduced renal perfussion
 Reduced Na+ delivery to the distal portion of renal tubule
 Increased K+
o Increases Na+ retention and K+ excretion
o Ca+ not affected by aldosterone (affected by PTH and Calcitonin)
o Decreased renal perfusion (ex. decreased plasma volume)  increased renin secretion  increased plasma
angiotensin II  increased aldosterone secretion  increased Na+ and H2O reabsorption and increased K+
excretion
Parenteral fluid (IV)
o Maintenance for daily body fluid requirements
o Replacement for existing deficits
o Restoration for concurrent or continuing losses
Crystalloids: solutes that, when placed in solution, mix with and dissolve into a solution and can’t be distinguished
from the resultant solution
o Potential to form crystals
o Diffuse through semi-permeable membrane
o Diffusion is related to osmolar gradients
Colloids: contain large molecules that don’t precipitate nor readily mitigate across capillary walls
o Albumin, dextran fluids (polysaccharides), Pentaspan, Mannitol, Hetastarch
0.9% NS: 25% in plasma and 75% in ISF (NONE in ICF)
o Advantages
 Expands ECF, adding fluid to ISF and plasma, restoring circulating volumes
 Treats Na+ depletion
 Initiates or terminates a blood transfusion
o Disadvantages
 Does not enter ICF so problem for cellular dehydration
 Provides more Na+ and Cl- than patients need causing hypernatremia
 May cause low K+
 Can lead to circulatory overload
5% Dextrose: 66% in ICF and 33% in ECF (8.25% in plasma)
o Advantages
 Act as vehicle for administration of medications
 Provides nutrients (minimal) sparing ketosis
 Can be used to treat cellular dehydration by providing free water
o Disadvantages
 Solutions of >20% dextrose can cause osmotic diuresis, vein irritation, rebound hypoglycemia if
discontinued too quickly
Hypertonic fluid therapy
o Can help stabilize BP, UO, and reduce edema
o Rarely used in pre-hospital setting
o Can cause cellular dehydration
% Albumin: 100% in plasma
Peripheral and intravascular lines
o Use distal viens of arm first
o Use nondominant arm
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Select vein that is easily palpated and feels soft and full, is naturally splinted by bone, and large enough to
allow adequate circulation around catheter
Avoid using veins that are in areas of flexion , highly visible, damaged by previous site, phlebitis, infiltration, or
sclerosis
3 days max length of time
Oral Rehydration
 Pedialyte: Na+, K+, Cl- (citrate), glucose
o Osmolarity 250mmol/L
 Common solutions
o Grape juice: 1170-1190mmol/L
o Apple juice: 650-730mmol/L
o Jello: 570-620mmol/L
o Breast milk: 320-340mmol/L
o Tea or water: 0mmol/L
 Homemade isotonic solution: 360mL unsweetened orange juice, 600mL boiled water, 2.5mL salt
 Indices of dehydration: status an anterior fontanelle
 Sodium
o Average Canadian consumption: 3400mg/day
o Goal by 2016: 2300mg/day
o Recommended intake: 1500mg/day for persons aged 9-50
o High sodium intake = elevated BP, osteoporosis, stomach cancer, asthma
 Potassium
o Hypokalemia
 Oral formulations
 Cause GI upsest (ex. nausea, vomiting, diarrhea, abdominal pain, discomfort)
 GI ulcerations, bleeding, performation and/or obstruction
 Do not administer undiluted or IV push K+
 Never > 60mmol/L – preferred 40mmol/L
 Never > 10-20mmol/hour
 Potassium rich foods: potato with baked skin, yogurt, milk, grapefruit juice, acorn squash, raw
spinach, strawberries, broccoli, chickpeas, watermelon
o Hyperkalemia
 Low potassium diet
 Increase elimination (diuretics, dialysis, ion-exchange ex. sodium polystyrene (Kayexalate))
 Correct acidosis as necessary
Acid Base Imbalances
 Volatile acid: eliminated by respiratory system as CO2 and H2CO3
 Nonvolatile acid: eliminated by renal system
 Acid production
o Aerobic respiration of glucose  carbonic acid
o Anaerobic respiration of glucose  lactic acid
o Oxidation of sulfur-containing amino acids  sulfuric acid
o Incomplete oxidation of fatty acids  Acidic ketone bodies
o Hydrolysis of phosphoproteins and nucleic acids  phosphoric acid
o CO2: 200mL/min, 8mmol/min, 12mol/day
o Metabolic acids: 70µmol/min, 0.1mol/day
 Respiratory acidosis
o Reduced SA for CO2 exchange
 Acute pulmonary edema, atelectasis, pneumothorax, hemothorax, pneumonia
o Pulmonary deficits reducing CO2 exhalation (direct blocking or loss of alveolar elasticity)
 Laryngospasm or laryngeal edema, foreign body aspiration, chronic obstructive pulmonary disease
o CNS lesions/deficits affecting medulla
 Cerebrovascular accident, increased intracranial pressure
o Conditions affecting respiratory muscles
 MS (advanced), Guillain-Barre syndrome, Sustained muscular paralysis post-op
o Acute respiratory acidosis
 Surgical anaesthesia, sedatives, pain, low tidal volume on MV, obesity
o Hypoventilation  increase in CO2 and H+  decreased pH  acidosis
o Signs and symptoms
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Severe: headache, disoriented, dizziness, drowsiness progressing to coma
Acute: stable (as in COPD) may be well tolerated but may have memory loss, sleep disturbances,
excessive daytime sleepiness, and personality changes
o Nursing care
 Correct underlying cause
 Prevent complications (ex. fall)
 Position to facilitate respiration
 Pursed lip breathing
 Symptomatic for mental status changes
 Mouth care
Respiratory alkalosis
o Hypermetabolic states (ex. high fever)
o Medulla stimulation (CNS lesions, encephalitis, septicemia, salicylate poisoning)
o High tidal volume on MV
o Hyperventilation  increased in CO2 and H+  increased pH  alkalosis
o Signs and symptoms
 Respiratory: hyperventilation
 Neurological: lightheaded, lethargy, confusion, syncope, circumoral or extremities numbness and
tingling, tinnitus
 Cardiovascualar: increased HR, arrhythmia
o Nursing care
 Correct underlying cause
 Prevent complications
 Re-breathing techniques (re-breathing mask, paper bag)
Metabolic acidosis
o Decrased acid excretion or HCO3- wasting (acute or chronic renal failure)
o Poisoning: salicylates, methanol (formaldehyde + formic acid), ethylene glycol (glycolic acid; oxalic acid)
o Loss of excess base from the body (severe diarrhea, bowel fistula)
o Ketoacidosis: excessive lipolysis (Diabetes 1, starvation) leads to hepatic production of ketones (Bhydroxybutyric and acetoacetic acids)
o Lactic acidosis: due to absolute or relative hypoxia (reduced oxygen to tissues), severe exercise, circulatory
shock
o Signs and symptoms
 Respiratory: increased depth of respiration (if compensating) to Kussmaul respirations
 Neurological: headache, confusion, drowsiness, coma
 Cardiovascular: flushed skin, decreased BP, arrhythmias (if hyperkalemia)
 GI: nausea, vomiting, diarrhea
o Nursing care
 Correct underlying cause
 NaHCO3
 Supportive care
 Address symptomatology
Metabolic alkalosis
o Loss of H+ (severe vomiting, NG suction)
o Excess alkali intake (Alka Seltzer)
o Signs and symptoms
 Respiratory: hypoventilation (if compensating)
 Neurological: dizziness, irritability, nervousness, confusion, tingling in periphery, seizure
 Cardiovascular: tachycardia, arrythmias (hypokalemia)
 GI: anorexia, nausea, vomit
o Nursing care
 Correct underlying cause
 Symptomatic care
 Avoid “washing electrolytes” from stomach (decreased ice chips, saline flushes)
 H2 receptor antagonists (PPI – if NG tube)
 Blocks HCl secretion and subsequent loss via suction
 Omeprazole (Losec), Iansoprazole (Prevacid)
 HCl solution if severe
Compensation
o Partial: pH moving toward normal
o Full: pH normal but PCO2 or HCO3 abnormal
Oxygenation
 Ex. A patient with severe diarrhea that has lasted 4 days is most at risk for which type of acid-base imbalance
o Metabolic acidosis: bicarbonate loss with diarrhea
o Metabolic alkalosis: loss of potassium
 PaO2 > 70, SaO2 > 95%: adequate unless unstable
 PaO2 60-70, SaO2 90-94%: adequate in most patients, O2 therapy may be prescribed depending on physiological
demands, instability
 PaO2 55-60, SaO2 88-90%: administration of O2 therapy required unless chronic hypoxemia
 Hypoxia
o Anemic hypoxia: decreased hemoglobin so low O2 carrying capacity
o Hypoxic hypoxia: O2 levels low despite O2 carrying capacity
o Circulatory hypoxia: reduced CO
o Histotoxic hypoxia: inability to adequately utilize available O2
 Pediatric variations
o Obligate nose breathers between 1-2 months
o Small trachea diameter; > compliant
o < acquired immunity
o Ingestion of foreign objects
o Decreased functional ability of cilia: less IgA produced by trachea under 2 years
o High O2 consumption
o Reduced functional cough ability under 1 year
 Sign and symptoms of hypoxemia
o Respiratory
 Early: tachypnea, dyspnea or exertion
 Late: dyspnea at rest, accessory muscles, retractions
o Cardiovascular
 Early: tachycardia, mild HTN, PVC
 Late: PVC, hypotension, cyanosis, cool and clammy skin
o CNS
 Early: unexplained apprehension, unexplained restlessness or irritability
 Early or late: unexplained confusion or lethargy
 Late: combativeness, coma
 Promoting oxygenation
o Position to enahnce chest expansion: fowlers position, good lung down if pneumonia or tumor
o Removal of secretions: cough, suctioning
o Incentive spirometer: cotton ball olympics
 Pros/Cons of Nasal Cannula
o Advantages
 Easy to apply
 Can receive O2 while eating, talking
 Relatively comfortable
 Permits some freedom of movement
 Usually well tolerated
o Disadvantages
 Delivers relatively low concentration of O2 (24% - 45%) at flow rates of 2-6L/min
 At > 6L/min, the clients tends to swallow air, and the FiO 2 is not increased
 Drying and irritating to the mucous membranes
 Ears can get ulcerated
o 1L/min: 24%, 2L/min: 28%, 3L/min: 32%, 4L/min: 36%, 5L/min: 40%, 6L/min: 44%
 Face masks
o Nasal cannula: 24-45% - 2-6L/min
o Simple face mask: 40-60% - 5-8L/min
o Venturi mask: 24-50% - 4-10L/min
o Partial rebreather: 60-90% - 6-10L/min
o Non rebreather mask: 95-100%; flow to prevent deflation
o Face tent: 30-50% - 4-8L/min
 Pros/cons of face masks
o Advantages
 Can provide relatively high amounts of oxygen
 No drying of mucous membranes with humidity
o Disadvantages
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Hot and confining
Moisture build up on skin
FiO2 can decrease if mask poorly fitted
Interferes with eating and talking
Nasal bridge excoriation
Key terms
o Tachypnea: >20/min
o Bradypnea: <12/min
o Eupnea: normal rate
o Orthopnea: dyspnea when lying down
o Dyspnea: subjective sense of difficulty breathing
o Hypoxemia: low O2 in blood
o Hypoxia: low O2 in tissues/cells
Surgery
 ASA Level
o 1: normal, healthy patient
o 2: mild systemic disease (asthma, HTN, obesity, tobacco, DM)
o 3: severe systemic disease that limits activity but not incapacitating (hy MI, uncontrolled DM, cancer)
o 4: severe systemic disease that is constant threat to life (renal failure, severe cardiac, pulmonary, liver
disease)
o 5: moribund patient not expected to survive 24 hours without OR (ruptured aneurysm, cerebral tumor, large
PE)
o 6: brain dead – organs being retreived
 Allergy
o Consiered at risk for latex allergy:
 Neural tube defects (spina bifida, meningocele)
 Chronic urinary catheterization
 Multiple surgical procedures
o Latex-food syndrome
 Banana, mango, kiwi, chesnuts, apple, carrots, avocado, strawberry, coconut, celery
 Fasting Pre-Op
o Clear liquids – 2 hours
o Breast milk – 4 hours
o Other milk – 6 hours
o Light meals (toast and clear liquids) – 6 hours
o Regular or heavy meals – 8 hours
 Thromboembolism risk levels
o Low risk (<10%): minor surgery or medical patients who are mobile
o Moderate risk (10-40%): most general, open gynecological, or urological surgery patients, medication
patients who are best rest or sick
o High risk (40-80%): hip or knee arthroplasty, hip fracture surgery, major trauma, spinal cord injury
 Preventive nursing interventions
o Ambulation
o Passive/active ROM (10-12x/1-2 hours awake) – flex and extend joints
o Leg elevation
o Compression stockings
 Surgical antiseptic skin preparation
o Pre-op: chlorhexidine-based solution with no rinse disposable chlorhexidine gluconate ipmregnated wash
cloths
o Intra-op: alcohol based chlorhexidine antiseptic instead of povidone-iodine
 Allow 3 minutes to dry – keep on 6 hours post-op
 Prophylactic antibiotics
o Completely absorbed in 60 minutes
o Surgeries longer than ½ life of antibiotic (4 hours) should be repeated
o Cardiac, thoracic, orthopedic, vascular patients: discontinued within 24 hours of end of surgery
o All others: no antibiotics post-surgery
 Length of surgery
o Predictive of dose of anaesthetic agents
o Pressure ulcer risk
o Fluid balance issues (especially in open surgeries)
o Atelectasis (in general anaesthesia)
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Intubation: paralysis of respiratory muscles requiring ventilator support requires endotracheal intubation
Laryngeal mask airway (LMA): inserted into pharynx and forms low pressure seal around larynx
Peri-operative normothermia: keep core temperature 36-38 degrees pre, intra, and post-op
o Warmed forced-air blankets
o OR temp 20 degrees
o Warming blankets under patient intra-op
o Hats and booties peroperatively
o Pre-warming
Positioning
o Skin breakdown potential with lengthy surgery
o Excess train on joints, muscles, skeleton in high risk patients
o Supine: calcaneus, sacrum and coccyx, thoracic vertebrae, olecranon, scapulae, occiput
o Prone (on stomach): toes, patellae, genitalia, breasts, cheek, eyes, and ear
 With laminectomy frame for spinal procedures
o Lateral kidney (on side): ear, acromion process, ribs, ilium, greater trochanter, medial and lateral condyles,
malleolus
Drains and catheters: urinary catheter, jackson pratt, IV infusion
Wound classification
o Clean: uninfected, no inflammation, respiratory, alimentary, genital, or uninfected urinary tracts not entered
o Clean-contaminated: respiratory, alimentary, genital, infected urinary tract entered under controlled
conditions and without unusual contamination (no break in sterile technique)
o Contaminated: open, fresh accidental wounds, major break in aseptic technique, gross spillage from GI tract
o Dirty of infected: preexisting infection (abscess, ruptured appendix)
Anaesthesia
o General anaesthesia
 Reversible, unconscious state – amnesia, analgesia, depression of reflexes, homeostasis or specific
manipulation of physiological systems and function
 Loss of sensation with loss of consciousness, skeletal muscle relaxation, analgesia, elimination of
somatic, autonomic, and endocrine responses including coughing, gagging, vomiting, and SNS
responsiveness
 Induction, maintainence, and emergence phases
o Local anaesthesia
 Reversible loss of sensation is a specific area or region of body
 Local infiltration
 Regional (peripheral) nerve block: spinal or epidural
 Spinal anaesthesia: L4-L5, L3-L4, L2-L3
PACU risks
o Respiratory
 Hypoxemia: atelectasis, pulmonary edema, pulmonary embolism, aspiration, bronchospasm
 Obstruction: tongue falling back, retained secretions, laryngeal edema, laryngospasm
 Hypoventilation: central respiratory drive depressed, poor respiratory muscle tone, mechanical
restriction, pain
o Cardiovascular: hypotension, hypertension, dysrhythmias
o Pain: unmanaged
o Temperature: hypothermia
o Surgical site: bleeding
o Neurological: LOC, disorientation, loss of sensory/motor, emergence delirium, delayed awakening
o GI/GU: N and V, renal failure
Atelectasis
o Most complication of general anaesthesia
o Occurs in 50-70% patients
o Collapse of alveoli thus preventing CO2 O2 exchange
o Symptoms: decreased air entry, elevated temperature (1-2 days post-op), dyspnea, reduced oxygen levels
o Mucous plug in bronchiole
o Collapse of alveoli due to absorption of air
Atelectasis and Pneumonia
o Decreased TV and decreased sigh reduced surfactant – prevent alveoli from expanding
o Poor ciliary movement
o Accumulation of mucus (intubation, decreased cough reflex due to pain, codeine, central depression)
o Recumbent position
o IgA altered due to traceal edema
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Preventive nursing interventions
o Periodic deep breaths: 10x/hour while away post-op 1-2 days
o Increases surfactant levels thus increasing alveolar surface tension
DVT
o PE in 50% cases
o Risk: pelvic surgery, orthopedic surgery, oral contraceptive therapy, obesity, lower limb trauma, elders
o Virchow’s triad
 Poor venous return (stasis)
 Hypercoagulability (stress response)
 Inflammation of endothelium