Fluids & Acid-Base Imbalance Flashcards
What percentage of newborns is composed of water?
75%
What percentage of infants are composed of water?
65%
What percentage of children / adolescents are composed of water?
50%
What factors contribute to electrolyte imbalance in children?
- body surface area
- ↑ RR
- ↑ respiratory & metabolic demands
What is different about the daily water need of newborns?
KNOW THIS!!!!!
4-5 times GREATER daily water need per kg
What 3 factors in children can lead to insensible fluid loss, dehydration, & electrolyte imbalance?
KNOW THIS!!!!!
- ↑ body surface area
- ↑ metabolic demands
- ↓ systemic regulation
Clinical Assessment of Fluid Imbalances - Vascular Volume
KNOW THE BOLD!!!!!
KNOW THIS!!!!! ↑ ↓
- Capillary refill
- ↓ pulse
- ↓ BP (= late sign)
- Central venous pressure (CVP)
- sunken fontanelles
- I/Os
- ↓ tears
- urine specific gravity
- mucous membranes
Clinical Assessment of Fluid Imbalances - Interstitial Volume
KNOW THIS!!!!
- Skin turgor
- Presence or absence of edema
What is 1 L of fluid lost equal to in terms of weight?
KNOW THIS!!!!!
1 kg lost (weight loss)
Normal Urine Output in Children
KNOW THIS!!!!!
0.5 - 1 mL/kg/hr
Normal Urine Output for an INFANT
KNOW THIS!!!!!
2 mL/kg/hr
What are the 3 main causes of dehydration in children?
KNOW THIS!!!!!
- ↓ intake
- ↑ output (GI loss, renal loss)
- translocation (burns, edema, etc.)
What are causes of dehydration?
KNOW THE BOLD!!!!!
- Diarrhea
- Vomiting
- Gastroenteritis
- Stomatitis or pharyngitis
- Fever
- DKA
- DI
- Burns
Isoctonic
KNOW THIS!!!!
- Fluid loss cannot be compensated by fluid intake
- Na+ & water are lost in proportion to each other
- Na+ is normal
H2O = Na
Hypotonic
KNOW THIS!!!!!
- Na+ loss is greater than water loss
- Na+ is low
- Fluid shifts from ECF to ICF to attempt to correct worsening dehydration
H2O < Na+
Hypertonic
KNOW THIS!!!!!
- Water loss is greater than Na+ loss
- Na+ is HIGH
- Fluid moves from ICF to ECF & thus s/s appear late
H2O > Na+
Mild Dehydration
KNOW THIS!!!!!
< / = 5% (40-50 mL/kg) loss of body weight
- Difficult to detect
S/S:
* Slightly ↓ urine output
* Moist mucous membranes
Moderate Dehydration
KNOW THIS!!!!!
6 - 10% (60 - 90 mL/kg) loss of body weight
S/S:
* sleepy / lethargic
* ↓ skin turgor
* ↓ urine output
* dark urine
* dry mucous membranes
Severe Dehydration
KNOW THIS!!!!
> / = 10% (100 mL/kg) loss of body weight
S/S:
* ↑ irritability
* lethargy
* non-responsive
* tachycardia (↑ HR)
* tachypneic (↑ RR)
* ↓ / absent urine output
How to Calculate IV Fluid Replacement
KNOW THIS!!!!!
1.) Calculate deficit for 24 hours
2.) Calculate Hourly Maintenance IV Fluids (MIVF)
3.) IV Rate = Deficit + MIVF
* Replace 50% in first 8 hours
* Replace 50% in the next 16 hours
Jimmy is a 4 year old boy brought to the pediatric ED by his mom. He has been vomiting & having diarrhea for 4 days. You determine that he has mild dehydration & your hospital recommends a fluid deficit of 40 mL/kg/24hr for this type of dehydration. He weighs 37 kg.
1.) Calculate the fluids needed to correct the deficit.
* 40 mL x 37 kg = 1480 mL
2.) Calculate the Bolus Amount (bolus is given 20 mL/kg over 30-60 minutes)
* 37 kg x 20 mL = 740 mL
3.) Calculate the MIVF Rate
* (10 kg x 4 mL/kg/hr) + (10 kg x 2 mL/kg/hr) + (17 kg x 1 mL/kg/hr) =
* 40 mL + 20 mL + 17 mL = 77 mL
- First hour he will receive 1 NS bolus of 740 mL (20 mL/kg bolus x 37 kg = 740 mL)
Then he will receive the remaining 740 mL (1480 - 740 = 740) deficit over the next 23 hours
* 740 mL / 23 hr = 32.17 mL/hr
* 32.17 mL + 77 mL = 109 mL/hr
Oral Rehydration Solution (ORS)
Product given for dehyration that contains complex carbs, sodium (Na+) & potassium (K+)
- avoid pop = increased diarrhea
Oral Rehydration
KNOW THIS!!!!!
1-2 tsp fluid every 10-15 minutes
4-2-1 Rule for Fluid Maintenance (holiday-segar method)
KNOW THIS!!!!!
- First 10 kg = 4 mL/kg/hr
- Next 10 kg = 2 mL/kg/hr
- Above 20 kg = 1 mL/kg/hr
4-2-1 Rule Example:
- Child’s Weight is 8.5 kg
8.5 kg x 4 mL/kg/hr = 34 mL / hr
multiply by 4 because the child is under 10 kg
4-2-1 Rule Example
- Child’s weight is 12 kg
- weight = 12 kg
1.) First 10 = (10 kg x 4 mL/kg/hr) = 40 mL/hr
2.) Second 10 = (2 kg x 2 mL/kg/hr) = 4 mL/hr
3.) Add –> 40 mL/hr + 4 mL/hr = 44 mL/hr
4-2-1 Rule Example:
- Child weighs 30 kg
- Child weighs 30 kg
1.) First 10 kg = 10 kg x 4 mL/kg/hr = 40 mL/hr
2.) Second 10 kg = 10 kg x 2 mL/kg/hr = 20 mL/hr
3.) Above 20 kg = 10 kg x 1 mL/kg/hr = 10 mL/hr
4.) ADD –> 40 mL/hr + 20 mL//hr + 10 mL/hr = 70 mL/hr
IV Fluid Bolus
KNOW THIS!!!!
NS or LR to expand vascular space & correct electrolyte changes
- 20 mL/kg over 30-60 minutes
Normal Sodium (Na+) level
KNOW THIS!!!!!!!
135 - 145
Normal Potassium (K+) levels
KNOW THIS!!!!!
3.5 - 5
Normal Calcium (Ca+) levels
KNOW THIS!!!!!
2.8 - 2.86
Normal Magnesium (Mg) levels
KNOW THIS!!!!!
1.6 - 2.4
Respiratory Acidosis
KNOW THIS!!!!!
↓ pH & ↑ CO2
- Causes: severe asthma, pneumonia, hypoventilation
Respiratory Alkalosis
KNOW THIS!!!!
↑ pH & ↓ CO2
- Causes: hyperventilation, panic attack, aspirin toxicity
Metabolic Acidosis
KNOW THIS!!!!!
↓ pH & ↓ HCO3
- Causes: DKA, lactic acidosis, EtOH
Metabolic Alkalosis
KNOW THIS!!!!!
↑ pH & ↑ HCO3
- Causes: vomiting = loss of acid
Causes of Hyponatremia
KNOW THIS!!!!!
- Diarrhea
- Vomiting
- Inadequate salt intake
- GI suctioning
- Diuretics
- CHF
- Forced excessive oral intake of tap water
- Excessive IV D5W
↓ Na+
Signs & Symptoms of Hyponatremia
KNOW THIS!!!!!
- Headache
- Poor skin turgor
- NEURO CHANGES!!!!!
- ↓ BP
- Dry mucosa
- Lethargy
- Confusion
- Seizures
- muscle weakness
- decreased deep tendon reflexes
↓ Na+
Causes of Hypernatremia
KNOW THIS!!!!!
- Inadequate breastfeeding intake w/ normal output
- Diabetes insipidus
- Diarrhea or vomiting
- Excessive sweating
- ↑ aldosterone
↑ Na
Signs & Symptoms of Hypernatremia
KNOW THIS!!!!!
- Thirsty
- ↓ urine output (unless ↑ Na is caused by DI)
- ↓ LOC (confusion, lethargy, coma)
- Seizures
- NEURO CHANGES!!!!
↑ Na
Causes of Hypokalemia
KNOW THIS!!!!!
- GI losses (vomiting, diarrhea)
- Medications
- Poor dietary intake (starvation)
- ↑ aldosterone (hyperaldosteronism, CHF, nephrotic syndrome, cirrhosis)
- ↑ cortisol (cushing disease)
- alkalosis
↓ K+
Signs & Symptoms of Hypokalemia
KNOW THIS!!!!!
- Muscle weakness & cramps
- Fatigue
- Anorexia
- Abdominal distension / constipation
- Nausea / Vomiting
- Dysrhythmias
↓ K+
Causes of Hyperkalemia
KNOW THIS!!!!
- Impaired renal function
- Crush injury
- Burns
- metabolic acidosis
↑ K+
Signs & Symptoms of Hyperkalemia
KNOW THIS!!!!!
- Cardiac changes & dysrhythmias
- Lethargy
- Muscle weakness
- GI symptoms (cramping & diarrhea)
- ↓ BP
- Dysrhythmias
↑ K+
Causes of Hypocalcemia
KNOW THIS!!!!!
- Malabsorption (poor diet, vitamin D deficiency)
- Alkalosis
- Chronic diarrhea
↓ Ca+
Signs & Symptoms of Hypocalcemia
KNOW THIS!!!!!
- NEUROMUSCULAR EXCITABILITY
- Laryngospasm
- Dyspnea
- Trousseau’s sign
- Chvostek’s sign
- Cardiac arrhythmias
- Seizures
↓ Ca+
Causes of Hypercalcemia
KNOW THIS!!!!!
- ↑ calcium absorption
- Vitamin D overdose
- Infants w/ very low birth weight who have inadequate phosphorus intake
- Children receiving TPN
- Bone tumors & other cancers
↑ Ca+
Signs & Symptoms of Hypercalcemia
KNOW THIS!!!!!
- Muscle weakness/ ↓ Neuromuscular excitability
- Incoordination
- Constipation, N/V
- Polyuria
- ↑ thirst
- Confusion, lethargy, & ↓ attention span
- Dysrhythmias
↑ Ca+
Causes of Hypomagnesemia
KNOW THIS!!!!!
- GI Losses
- Enteral or parenteral feeding deficient in magnesium
- ↓ Mg Absorption (due to chronic diarrhea, short bowel syndrome, malabsorption syndromes, & teatorrhea)
- Prolonged NG Suction
- Can also be caused by DKA, sepsis, burns, & hypothermia
↓ Mg+
Signs & Symptoms of Hypomagnesemia
KNOW THIS!!!!!
- ↑ NEUROMUSCULAR EXCITABILITY
- Hyperactive reflexes
- muscle cramps
- twitching / tremors
- cardiac arrhythmias
↓ Mg+ = ↑ Neuromuscular excitability
Causes of Hypermagnesemia
KNOW THIS!!!!!
- Renal Failure (oliguric renal failure & adrenal insufficiency)
- DKA
- Excessive administration of Mg
- Apsiration of sea water (drowning)
- Adisson Disease
↑ Mg+
Signs & Symptoms of Hypermagnesemia
KNOW THIS!!!!!
- ↓ NEUROMUSCULAR EXCITABILITY
- Drowsiness / lethargy
- Hypotension (↓ BP)
- Weak / absent deep tendon reflexes
- Bradycardia (↓ HR)
↑ Mg+ = ↓ Neuromuscular Excitability
What does a depressed fontanelle indicate?
KNOW THIS!!!!!
Dehydration
What does a full or bulging fontanelle indicate?
KNOW THIS!!!!
Fluid overload or ↑ ICP
What percentage of weight loss is conidered mild, moderate, and severe in children?
KNOW THESE!!!!!
- Mild: < 5%
- Moderate = 6 - 9%
- Severe: >/= 10%
Calculate Daily Fluid Maintenance
KNOW THIS!!!!
- Usual Weight: up to 10 kg → 100 ml/kg/24 hr
- Usual Weight: 11 - 20 kg → 1000 mL + (50 ml/kg for weigth above 10 kg)/24 hr
- Usual Weight: > 20 kg → 1500 mL + (20 ml/kg for weight above 20 kg)/24hr
