PULMONARY Flashcards
normal ventilation is…
~4L/min
anything that affects heath of diaphragm (deconditioning, hypoxemia, acidosis, hypophosphatemia) will adversely affect what?
ventilation
PE results in…
increased alveolar dead space; clot in pulmonary circulation; no blood flow past alveoli in that area of pulmonary circulation
normal ventilation/perfusion ratio:
4L ventilation/min (V) / 5L perfusion/min (Q)
ideal lung unit = 0.8 ratio, normal V/Q ratio
FiO2 0.21
good/bad lung down and why?
good because we want the blood to perfuse the good lung; if bad lung is down, more blood will go to that lung but pt may become hypoxemic
what is a shunt? what is the treatment?
extreme V/Q mismatch; 100% FiO2 will NOT correct hypoxemia; EX: ARDS
give 100% O2, PEEP to increase alveolar recruitment and prevent alveolar collapse
a shunt is the movement of blood from where in the heart?
right to left side of heart without getting oxygenated; venous to arterial
what is the normal physiological shunt?
thebesian veins of heart empty into the left atrium; reason why normal O2 sat on RA is 95-99%, never 100%
what is an anatomic shunt?
VSD or ASD
what is a pathologic shunt?
ARDS - blood goes to lungs but does NOT get oxygenated –> refractory hypoxemia
what are the benefits of PEEP?
prevents expiratory pressure from returning to 0, keeps it (+)
decreases surface tension of alveoli, preventing atelectasis
increase alveolar recruitment
increases driving pressure, extends time of gas transfer, allow decrease in FiO2
adding PEEP will help hypoxemia and decrease FiO2
pt with severe sepsis/septic shock may have normal PaO2, SaO2, hgb, clear lungs, adequate ventilation, and oxygen delivery, and a lactate of 10. why?
lactic acidosis because oxygen utilization is affected by sepsis/septic shock and results in anaerobic metabolism
what clinical indications make hemoglobin “hold on” to oxygen molecules and causes a shift of the oxyhemoglobin dissociation curve to the left?
aLkaLosis
Low PaCO2
hypothermia (coLd)
low 2,3-DPG
SaO2 high but O2 stuck to hgb and tissues do not get needed O2 as readily
what clinical indications make hemoglobin “release” the oxygen more easily to the tissue and causes a shift of the oxyhemoglobin dissociation curve to the right?
acidosis
high PaCO2
fever
high 2,3-DPG
good for tissues; SaO2 low but O2 easily released to tissues
what is 2,3-DPG? and what do high/low levels indicate?
organic phosphate in RBCs that has the ability to alter the affinity of hgb for oxygen
high levels results in hgb more readily releasing O2 to tissues
low levels results in hgb holding on to O2, less O2 available to tissues
what are some causes of decreased 2,3-DPG?
multiple blood transfusions
hypophosphatemia
hypothyroidism
what are some causes of increased 2,3-DPG?
chronic hypoxemia (high altitudes, chronic HF)
anemia
hyperthyroidism
carboxyhemoglobin levels and symptoms
0-5% normal <15% often in smokers, truck drivers 15-40% HA, confusion 40-60% LOC, Cheyne-Stokes respirations 50-70% mortality
what is the treatment for carbon monoxide poisoning?
100% FiO2 until sx resolve and carboxyhemoglobin level is <10%
hyperbaric oxygen chamber if available within 30min
what is static compliance?
measurement of elastic properties of LUNG
normal is ~45-50ml/cm H2O
TV/plateau pressure (minus PEEP)
what is dynamic compliance?
measurement of elastic properties of AIRWAYS
normal is ~45-50ml/cm H2O
TV/peak inspiratory pressure (minus PEEP)
patients with pulmonary problems that involve mainly the lungs have a decrease in static compliance but dynamic compliance may also be decreased, why?
lung pressures may transmit up to the airways
i.e. ARDS
how would static and dynamic compliance be in a status asthmaticus patient?
static compliance would be normal
dynamic compliance would be low
what is anion gap?
difference between positive and negative anions
normal 5-15mEq/L
what are some problems associated with an increase in anion gap?
Ketoacidosis Uremia Salicylate intoxication Methanol Alcoholic ketosis Unmeasured osmoles: ethylene glycol, paraldehyde Lactic acidosis: shock, hypoxemia
what are some problems associated with a normal anion gap?
saline infusion (hyperchloremic acidosis)TPN
diarrhea
ammonium chloride
ARF, sometimes chronic
respiratory failure is…
rapidly occurring inability of lungs to maintain adequate oxygenation of the blood with or without impairment of carbon dioxide elimination
ABG - PaO2 of 60mmHg or less, with or without elevation of PaCO2 to 50mmHg or more with pH <7.30
what problems can lead to type 1 hypoxemic respiratory failure?
PNA, ARDS, atelectasis, pulmonary edema, massive PE, interstitial fibrosis, asthma
what problems can lead to type 2 hypercapneic respiratory failure?
CNS depression r/t drugs (opiates, sedatives), increased ICP, COPD (including asthma), flail chest, ALS, Guillian-Barre syndrome, MS, myasthenia graves, SCI
what problems can lead to type 3 combined respiratory failure?
ARDS, asthma, COPD
what are some S/S of acute hypoxemic respiratory failure?
pulmonary - tachypnea, adventitious breath sounds, accessory muscle use
cardiac - tachyarrhythmias (initial), bradyarrhythmias (late), HTN/hypoTN, cyanosis
neuro - anxiety, agitation
what are some S/S of acute hypercapneic respiratory failure?
pulmonary - shallow breathing, bradypnea, BS clear or adventitious
neuro - progressive decreased LOC