respiratory labs Flashcards
Causes of Respiratory Disease
Tumors:
Infections:
Airway diseases:
- emphysema
- bronchitis
-asthma
- RDS
Pulmonary vascular disease:
-PE
- P HTN
Interstitial lung disease:
- affect the tissue and space around the alveoli
- impaired diffusion of gases
- sarcoidosis, pneumoconiosis
Common Locations for an ABG: where do you palpate the arteries
Radial artery: *
- Palpated between the distal radius and the tendon of the flexor carpi radialis
- need to do modified allen test to make sure collateral circulation working
Femoral artery:
- Palpated below the midpoint of the inguinal ligament
Modified Allen Test
- Tests for sufficient arterial blood flow to the hand prior to an ABG draw
1) hold hand high and make a fist while compressing ulnar and radial arteries (blanched hand)
2) lower hand and release fist
3) release pressure off ulnar artery
4) watch hand turn pink within 6s to indicate patent collateral blood flow
- patent ulnar artery
- intact superficial palmar arch
- -if flow is not restored to hand -> you cant do an ABG on this hand -> no collateral flow
components of typical arterial blood gas kit
-arterial blood gas syringe
-protective needle
-syringe cap
-iodine and alcohol preparation swabs
-gauze
-pt label
-biohazard ice bag
-adhesive bandage
-sample goes on ice
femoral artery anatomy/puncture
NAVEL:
-outside to inner- femoral nerve, artery, vein
-femoral artery can be palpated just below midpoint of inguinal ligament
-blood draw- 90 degree angle
-catheter: 45 degree angle -> “snaking a line:” threading a thin tube through the artery to reach various parts of the body
Code type situation: we all need to be able to check femoral pulse
Key Components of the Blood Gas Test Panel:
pO2 (Partial Pressure of Oxygen)
- low = hypoxemia
pCO2 (Partial Pressure of Carbon Dioxide)
- high = hypercapnia
pH
- Normal: 7.35 to 7.45
Body’s Response to Acid-Base Disturbances
Lungs respond within MINUTES:
-ex. if you put a pt on a ventilator, the lungs respond in mins, redraw ABG can be done within mins
-Respiratory Acidosis: can increase rate on ventilator to tx
-Respiratory Alkalosis: reduce ventilator
Renal response takes hours/DAYS:
-can’t check immediately
- response: can excrete H+ and retain HCO3-: INCREASE pH
- retain H+ and excrete HCO3-: lower pH
Respiratory Acidosis
ABG Findings:
- Low pH
- high pCO2
Cause: HYPOventilation*
- COPD exacerbations
- severe asthma
- airway obstruction
Metabolic Acidosis
Low pH (acidic) and low bicarbonate (HCO3−)
Examples:
- DKA: uncontrolled DM* tx with IV insulin
- lactic acidosis from shock
- severe dehydration
need to calculate ANION GAP
- normal anion gap: acidosis is due to a loss of bicarbonate, which could be from GI or renal causes
- elevated: due to additional acids in blood - MUDPILES (DKA, renal failure)
Respiratory alkalosis
High pH, low CO2
Causes: hyperventilation *
- severe anxiety/pain
- pneumonia
- PE
- high altitudes
- pregnancy
ALKalosis: “tALKative ppl need to hyperventilate to talk more”
Metabolic alkalosis
High pH, high HCO3
Causes: loss of H+ or HCO3- excess
- Severe chronic vomiting *: huge loss of H+ in stomach
- diarrhea
- laxatives
- loop diuretics
- hyperaldosteronism: mineralocorticoid excess
importance of Proper ABG Sample Handling
ABG blood draws must always be placed on ICE IMMEDIATELY after collection:
- at room temperature: metabolic processes continue within the blood sample -> consumption of O2 and production of CO2
- not on ice = alterations in pH*
- pO2 will decrease and pCO2 increases: pH will be skewed to be more acidic
Anion Gap: what electrolytes
Cations: Na+ and K+
Anions: Cl− and HCO3−
Normal anion gap: <12
Elevated: greater than 12-16
- indicates presence of additional acids in the blood (DKA!!)
Causes of Increased Anion Gap
“MUDPILES”
M methanol
U uremia
D DKA
P Propylene glycol
I iron tablets or INH
L lactic acidosis
E ethylene glycol
S salicylates (aspirin)
Causes of normal Anion Gap
HARDASS
H hyperalimentation
A addison’s ds
R renal tubular acidosis
D diarrhea
A acetazolamide
S spironolactone
S saline infusion