B4-054 Respiratory Failure Flashcards
indications for mechanical ventilation:
respiratory failure
4
- hypoxia
- hypercarbia
- perioperative
- metabolic
indications for mechanical ventilation:
upper airway obstruction
3
- anaphylaxis
- angioedema
- trauma
indications for mechanical ventilation: airway protection
3
- decreased GCS
- cardiac arrest
- prevention of aspiration
type 1 respiratory failure
hypoxemia
type 2 respiratory failure
hypercarbia
type 3 respiratory failure
perioperative
type 4 respiratory failure
metabolic
occurs with alveolar flooding and subsequent VQ mismatch and intrapulmonary shunt physiology
type 1 hypoxia
pulmonary edema, lung injury, pneumonia or hemorrhage can cause what type of respiratory failure?
type 1 hypoxia
low inspired oxygen
VQ mismatch
shunt
diffusion limitation
cause
type 1- hypoxia
in the case of a shunt, will supplying supplemental oxygen improve ventilation?
no
- impaired CNS drive to breathe
- impaired neuromuscular strength
- impaired resistance
cause
type 2 hypercarbia
lab findings pH < 7.2 and PaCO2 >45 or significantly elevated from baseline
type 2 hypercarbia
- atelecstasis
- decreased airway protection
- airway injury
- procedural need
causes for
type 3 perioperative
hypoperfusion of respiratory muscles
can cause
type 4 metabolic
what should you do if your patient is hypoxic?
- sit up
- oxygenate
- stimulate
- history
- labs/imaging
- call for help
flow 1-6L
FiO2 24-45%
nasal cannula
flow 1-7 L
FiO2 30-55%
reservoir nasal cannula
flow 10-60 LPM
FiO2 21-100%
heated high flow cannula
he also called this comfort care
flow 6-10 LPM
FiO2 35-50%
simple face mask
flow 2-15 LPM
FiO2 24-60%
venturi mask
flow 10-15 LPM
FiO2 -80%
non rebreather
induction agents
4
- propofol
- ketamine
- etomidate
- benzodiazepines
blunting of airway reflexes
2
- lidocaine
- opiods
neuromuscular blockage
depolarizing vs nondepolarizing
GABA receptor agonist
3
- propofol
- benzos
- etomidate
- most common agent used before surgery
- used to maintain general anesthesia before surgery
propofol
NMDA receptor antagonist
ketamine
- decreases pain with injection of propofol and etomidate
- causes tinnitus, perioral tingling
lidocaine
- typically IV fentanyl
- causes respiratory depression
opioids
succinylcholine is a
depolarizing agent
mimics acetylcholine and produces sustained depolarization of the post junctional membrane
succinylcholine
rocuronium, vecuronium, cisatracurium are
non depolarizing agents
most common trigger for perioperative anaphylactic events
non depolarizing agents
reversal agent for rocuronium/vecuronium
suggamadex
MH trigger
succinylcholine
history red flags for intubation
- OSA
- neck radiation
- difficulty controlling secretions
physical exam finding red flags for intubation
- BMI > 30
- neck circumference > 40
- edentulous
- small mouth
- limited neck mobility
- thyromental distance < 6
- beard
purpose of preoxygenation
breathing 100% oxygen can replace nitrogen and increase the amount of oxygen lungs can hold
proper positioning for intubation
- 35 degrees of cervical flexion
- elevation of the head on firm cushion
- rapid anesthesia induction, short DOA
- may cause respiratory depression and decreased BP
propofol
- causes hallucination, vivid dreams
- sympathomimetic
ketamine
an intrapulmonary problem associated with an A-a gradient
type 1 hypoxemia
- ventilatory problem
- the integrity of the alveolar capillary unit is normal
- A-a gradient normal
type 2 hypercarbia
normal A-a gradient
(Age + 10)/4
acute hypercapnea is always accompanied by
respiratory acidosis
PaCO2> 45 mmHg
hypercapnea
hypercapnic respiratory failure is typically caused by two things
decreased minute ventilation
increased dead space
alveolar gas exchange is inversely related to
PaCO2
a change of 10 in CO2 causes a pH change of
0.08
If alveolar ventilation is reduced by half, PaCO2 will
double
usually due to alveolar hypoventilation
respiratory acidosis
usually due to alveolar hyperventilation
respiratory alkalosis
due to:
* increased production of acids
* increased loss of bicarb
* decreased renal excretion of acids
metabolic acidosis
due to:
* intracellular shift of H+ ions
* GI H+ loss
* excessive renal loss of H+
metabolic alkalosis
- causes inhibition of 11B hydroxylase resulting in short term adrenal insufficiency
- low cortisol, hyponatremia, hyperkalema, fatigue, weakness, hypotension
etomidate
- typically given during intubation and mechanical ventilation to blunt reflexes
- can also be given for pain control and sedation
fentanyl
- commonly used to provide rapid muscle relaxation during rapid sequence induction
- causes depolarization of neuromuscular junction leading to paralysis
succ
- most significant side effect is MH
- rapid elevation of temperature, muscle rigidity, metabolic acidosis, and CV instability
succ
potential side effect is pseudocholinesterase deficiency causing prolonged paralysis
succ
- commonly used for induction and sedation that acts on GABA
- short acting, rapid anesthesia, quick recovery
propofol
potential side effect causing metabolic acidosis, rhabdomyolysis, hyperkalemia, cardiac dysfunctio, renal failure
propofol infusion syndrome
normally respiratory muscles consume 5% of total CO, but in shock, up to […] of the CO can be redirected to respiratory muscles
40%
mechanical ventilation may be required just to let CO distribute properl
acute respiratory acidosis, pH should be about
7.24
acute metabolic acidosis, PCO2 should be
low
metabolic alkalosis, pH should be […] and HCO3 should be […]
pH > 7.4
HCO3 > 24
with chronic respiratory alkalosis, pH should be […] and HCO3 should be […]
pH: near normal
HCO3: low
alveolar ventilation increases as RR
increases
alveolar ventilation increases as tidal volume
increases
alveolar ventilation increases as dead space
decreases
opioid overdoses cause what type of respiratory failure?
hypercapnic
respiratory acidosis
