ICU Flashcards
hypoxia
decreased O2 delivery to TISSUE
hypoxemia
decreased arterial oxygen tension
MC causes of dypsena
obstructive dz PNA ischemia psychogenic CHF
LIFE threatening cause of dypsnea
upper airway obstruction PE tension PTX Fat emboli muscle neurogenic (MG, GB, botulism)
mild respiratory distress
sentences
22 RR
NML consciousness
moderate respiratory
23-28 RR
3-5 word sentences
severe respiratory distress
> 28 RR
0-1 words
AMS/Fatigue
mechanism of hypoxia
decreased O2 saturation
decreased cardiac output
decreased hemoglobin
mechanisms of hypoxemia
R to L shunt hypoventilation decreased diffusion low O2 intake VQ mismatch
R to L shunt
blood skipping pulmonary circuit oxygenation before going to tissue
WILL NOT IMPROVE WITH OXYGENATION
body response to hypoxemia
increased minute ventilation
sympathetic response (Increased HR, CO)
pulmonary vasoconstriction
diagnosis of hypoxemia
ABG PaO2 < 60
hypercapnia
caused by HYPOVENTILATION
PaCO2 > 45
etiologies of hypercapnia
- decreased respiratory drive
- decreased tidal volumes
- rapid shallow breathing
Alveolar volume =
Tidal Volume - Dead space
alveolar hypoventilation via:
decreased respiration
decreased tidal volume
increased dead space
DDX of hHypercapnia
decreased central respiratory drive (brainstem lesion, opioids/sedatives, tetanus)
thoracic cage disorder
neuromuscular impairment (organophosphate)
COPD
actue hypercapnia s/ s
raises ICP = vasodilation
HA, dyspnea, confusion
peropejra; ams cpmkimctova; ju[ere,oa
chronic hypercapnia ABG
this state is actually tolerated, pts adjust
Bicarb >28
PCO2 >45
Normal pH
diagnosis of hypercapnia
ABG
Chronic: large bicarb compensation (kidney)
Acute: mild elevation in bicarb bc kidney can’t keep up
tx hypercapnia
increased minute ventilation via BiPap/CPAP
central cyanosis
tongue + mucous membranes
inadequate pulmonary oxygen or abnormal HgB
via hypoxemia, VQ mismatch, RL shunt, HgB abnormalities
peripheral cyanosis
extremities and digits
vasoconstriction/diminished peripheral flow
via decreased CO, cold extremities, shock
dx and tx cyanosis
ABG
supplemental oxygen
criteria for diagnosing ARDS
- new bilateral infiltrates
- respiratory failure not explained by HF/volume
- impaired oxygenation
pathogenesis ARDS
interstitial and alveolar pulmonary edema , alveolar collapse, hypoxemia
respiratory failure
abnormalities of oxygenation or ventilation
pulmonary and non pulmonary
s/s of respiratory failure
hypoxia and hypercapnia
high decree of suspicion + ABGs
indications for mechanical vent
- hypoxemia
- upper airway obstruction
- impaired airway protection
- inability to clear secretion
- respiratory acidosis
- progressive fatigue, tachympna AMS’
- Apnea
modes of mechanical vent
- controlled mechanical vent (VC/PC)
- SIMV
- Pressure support
- T piece
tidal volume based on
IDEAL body weight (5-7 L/kg)
respiratory failure and mechanical vent
Lung protective ventilation (lower tidal volume)
postivie pressure ventilation
decreased diastolic filling and increases output during systole
REDUCES ventricular filling therefore preload and afaterload changes
assisted control
volume and flow rate OR pressure and I:e ratio
PEEP
ventilation setting
keeps small airway open to reduce damage to alveolar
peak airway pressures should be less than
35
CMV
continuously pumps air in despite patient effort
not common
assist control MOA
vent delivers MINIMUM number of supported breathes
pt breath triggers fully assisted vent reacts but machine will breath if pt doesn’t
SIMV
combined ventilation with spontaneous breathing
limits breath when pt is exhaling but delivered minimum number
completely turns off it pf breathes
airway devices steps
pressure control/bipap (awake, can trigger breath) - NO SET RATE
SIMV v (assisted, coincides with inspiratory)
AC (pt trigger or machine trigger, BREATHES for pt)
general supportive care ventilation
decreased potassium
decreased phosphate
sedatives/hypnotics
analgesics
mechanical vent complications
atelectasis.overextension barotrauma volutrauma respiratory alkolosis HoTN VAP
