pulm function tests Flashcards by Jessica B

PFT is usually

spirometry

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pt’s at risk for post op pulm complications

significant hx of pulm disease, thoracic or abdomical surgery, obesity, long term smoker, elderly >70

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normal FEV1 is 5, patient should be able to get __% of that which is

80, 4

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high risk result for FEV1

<2 L

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high risk result for FEV1/FVC

<0.5

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normal FEV1/FVC

80%

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high risk VC in adult

<15cc/kg

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high risk VC in child

<10cc/kg

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why PFT pre-op

good to know pulm reserve so you can plan

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bronchodilators are most important pre-op for patients with

> 15% improvement in FEV1 after treatment

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normal I:E

1:2

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severe emphysema requires longer

expiratory times 1:3

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rapid correction in EtCO2 leads to

metabolic alkalosis.

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the body handles acidosis or alkalosis better?

acidosis

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with bronchospasm you should aviod

histamine releasing drugs

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why does your patient become light when you treat with nebulized albuterol?

because it takes 10L of oxygen so youre diluting your gas

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in terms of extubation, if FEV1 is ____ predicted, then extubation prob wont be effected

> 50%

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if FEV1 is ___ predicted, only do life saving procedures under general

<25%

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if FEV1 is between 25-50% with some hypoxemia and hypercarbia..

prolonged intubation probable

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to extubate, RR should be less than

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to extubate, ABG of 40% should show

PaO2 >70 and PACO2 <55

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to extubate, NIF should be

Negative Inspiratory Force

more negative then -20 cm H20

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to extubate, vital capacity should be

> 15cc/kg

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to intubate resp rate is

> 35

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to intubate VC is

<15cc/kg in adult or <10cc/kg in child

intubate if NIF is less negative than

-20cm H2O

intubate if PaO2 is

<70 on FiO2 of 40%

intubate if A-a gradient is

> 350 mmHg on 100% O2

intubate if PaCO2 is

>55

intubate if vd/vt is

>0.6 | dead space to tidal volume ratio

intubate if clinically

airway burn, chemical burn, epiglottis, ams, rapidly deteriorating pulm status, fatigue

if youre worried about pneumothorax, get an X-ray on

exhalation

ABG must be measured within __ or what happens

15min , glycolysis will occur with lactic acid production, ↓ pH and ↑ PCO2

ABG can be stored on ice for

1-2h

heparin may significantly lower PCO2 by

dilution, esp in children

buffer

substance that can absorb or donate H+

examples of buffers

bicarb (HCO3), hb, serum proteins, phosphate (HPO4)

normal ph

7.35-7.45

normal PCO2

35-45

normal PaO2

75-105

normal bicarb

20-26

normal base excess

-3 to +3

blood gas machine assumes the person is breathing

Room air

an increase in PaCO2 by 10mmhg causes a ____ in ph by ___

decrease 0.08

an decrease PCO2 by 10 will ___ ph by ___

increase 0.08

hypoxemia is PaO2

<75

A-a gradient measures

efficiency of lung, how well is oxygen making it from your lungs to your normal blood supply

normal A-a is approx

age/3

how does anesthesia affect A-a

widens

A-a is ___ with hypoventilation or low FiO2

normal

A-a is ____ with intrinsic lung disease - PTX,PE,Shunt, v/q mismatch, diffusion problems

widened

a decrease in bicarb by 10 ___ the pH by ___

decreases 0.15

bicarb and ph are ___ , PCO2 and ph are ___

direct, indirect

an increase in bicarb by 10 ___ the ph by

increases 0.15

** total body bicarb deficit =

base deficit x weight in kg x 0.4

usually replace ___ of total body bicarb deficit

half

resp acidosis caused by ____ventilation and ____carbia

hypoventilation , hyper

resp acidosis is ___ ph and ___ Paco2

low ph high PACO2

resp acidosis causes ___ FRC

decreased

causes of resp acidosis

sleep apnea, obesity, trauma drugs CNS depression, upper or lower airway obstruction, asthma, pulm fibrosis

after __ days of resp acidosis, renal compensation occurs

1-2 days

how do the kidneys compensate for resp acidosis

H+ is excreted by the kidney and HCO3 is reabsorbed into blood to partially correct pH

resp alkalosis is __ph and __ paCO2

high, low

resp alkalosis is caused by ___ventilation and ___carbia

hyperventilation, hypocarbia

resp alka is caused by

hypoxic respiration (mtn climbing), CNS disease, encephalitis, anxiety, narcotic withdrawal, *pregnancy, artificial ventilation

how do the kidneys compensate for resp alkalosis

decreased secretion of H+ and increased excretion of HCO3, which partially corrects pH

meta acidosis is ___ph and ___HCO3

low low

causes of metabolic acidosis

lactic acidosis* from hypo perfusion, DKA,renal dz with bicarb loss (anion gap and k+), *diarrhea, ASA ingestion, high protein intake

metabolic acidosis compensation

resp compensation(central chemoreceptors) with hypocarbia, more rapid than renal compensation, partial correction

metabolic acidosis kidneys..

may increase H+ excretion

metabolic alkalosis ph and hco3

high ph and high hco3

causes of metabolic alkalosis

bicarb infusion,metabolism of lactate or citrate, loss of H+ from vomiting or excessive NGT suctioning

resp compensation for met alka

limited hypoventilation due to eventual hypoxic drive, partial correction (cant slow respirations down enough)

metabolic alka kidneys

may increase bicarb excretion in urine

FRC is

ERV +RV

what decreases FRC

obesity, full belly,pregnant, trendelenberg

what is the most important clinical tool in assessing the severity of airway obstructive disease

FEV-1second

FEV -1 second definition

after max inspiration, the volume of air that can be forcefully expelled in one second

whats a normal FEV-1

3-5L

FEV1/FVC

>75%

FEV1/FVC can tell you

how severe their obstructive lung disease is

mild risk

60-75

moderate risk

45-60

severe risk

35-45

extreme risk

<35

FEF 25-75 is effort ____

independent

FEF 25-75 reflects

collapse of small airways, peripheral airways. sensitive indicator early airway obstruction

MVV or MBC

maximal breathing capacity- "will to live" test

MVV is effort ___

dependent , non-specific

extrathoracic obstruction decreases ___ flow | upper airway obstruction

inspiratory

intrathoracic obstruction decreases ___ flow | generalized pulmonary disease

expiratory

the downward slope on pressure volume loop is

FEV1