Mechanical Ventilation Flashcards
ventilation/perfusion (v/q)
air going in and out of lung/ blood circulating to area of lung
V/Q in top areas of lung
higher ratios because there is more ventilation in the upper portions of the lung and less perfusion –> higher oxygenation
V/Q in lower areas of lung
lower ratios because more perfusion but less ventilation (can’t saturate area of perfusion) –> less oxygenation
V/Q mismatch
certain areas of the lung have high v/q ratios and some have low v/q ratios; most common cause of hypoxemia; will respond to 100% O2 and has an increased Aa gradient
possible causes of V/Q mismatch
pneumonia, PE, COPD, asthma, pulmonary HTN, fibrosis
pulmonary shunting
does not respond to 100% O2; increased Aa gradient
O2-Hgb Dissociation curve
relationship b/t PaO2 and % saturation of Hgb
shift of curve to the right
more difficult to pick up at lung but easier to drop off at tissues; causes: decreased pH, increased pCO2, hyperthermia, chronic hypoexemia
shift of curve to the left
easier to pick up at lung but more difficult to drop off at tissues; causes: increased pH, decreased pCO2, hypothermia, banked blood
normal pH
(acd.) 7.35 - 7.45 (alk.)
normal PaO2
80-100%
normal PaCO2
(alk.) 35-45 (acd.)
normal HCO3
(acd.) 22-26 (alk.)
SLOPE for intubation: S
Suction, syringe, stethoscope, sedation, stylet
SLOPE for intubation: L
lubricant, laryngoscope
SLOPE for intubation: O
oxygen
SLOPE for intubation: P
patient positioning, pressure
SLOPE for intubation: E
ETT, end-tidal CO2
cuff pressure
20-25 mmHg; want the cuff inflated enough to prevent aspiration but not too inflated where it could lead to tracheal necrosis; check Q6-8hr
ETT care
verify placement by auscultation, EtCO2 and x-ray, secure the tube, monitor position (cm marking), suction only PRN, monitor for skin breakdown, prevent dislodgement, monitor cuff pressure (q 6-8hr), ambu bag at bedside
ETT suctioning
make sure pt is stable first, no more than 10 seconds, no more than 3 attempts; no difference b/t intermittent and continuous suctioning on closed system like this, nurses will probably continually suction upon withdrawal; no more than 120 mm of suction
ETT complications on insertion
nasal, oral, pharyngeal, or hypopharyngeal trauma, vomiting with aspiration, cardiac arrest
ETT complications while in place
nasal/oral inflammation and ulceration, sinusitis/otitis, larygneal and tracheal injuries, tube obstruction and displacement
oral hygiene importance
very vulnerable to develop VAP, more bacteria in mouth
VENTS: V
View, monitor ABGs, airway, and resp. status
VENTS: E
Elevate HOB 30 degrees, Equipment at bedside (ambu bag and suction)
VENTS: N
Notice GI complications (stress ulcers), Nutritional needs
VENTS: T
Take note of settings and alarms
VENTS: S
Suction tracheal tube, Secretions, Self-protection, Soft wrist restraints
ETT obstruction
bite block, sedation, suction, humidify, replace
ETT displacement
secure, restrain, sedate, support tubing, replace
ETT fistula/stenosis
cuff inflation, monitor cuff pressure, tracheostomy
ETT skin breakdown
loosen tube holder at least q24hr and change sides, inspect skin
ETT related infection
use sterile technique
reasons for mechanical ventilation
acute respiratory distress, surgery, post-surgery, OD, sedation, head trauma
negative pressure ventilators
not seen often, might be on someone with muscular dystrophy; applied externally to pt and decreases the atmospheric pressure surrounding the thorax to initiate inspiration
positive pressure ventilators
uses a mechanical drive mechanism to force air into the pt’s lungs through an ETT or tracheostomy
assist-control mode
all breaths are mandatory, triggered from either the pt or the machine; if pt initiates breath, the full volume set on vent will be given
synchronized intermittent mandatory ventilation (SIMV) mode
set minimum rate and tidal volume, pt able to breathe spontaneously b/t mandatory breaths; the breaths initiated by the patient would be whatever volume they can do - not the set amount from the vent
Spontaneous mode
(CPAP or PSV) all breathing is determined by the patient, there is no “trigger mode” offered by machine
controlled breath
ventilator does all the work, pt does nothing
assisted breath
pt initiates breath and the ventilator takes over
supported breath
pt able to do some or most of the work but the ventilator assists to finish (like pressure support)
pressure control
preset pressure limit, delivered volume variable depends on pt’s compliance
benefits to pressure control
airway pressure limited, and prevents damage to alveoli
cons to pressure control
if resistance rises or compliance falls in the pt’s airway or chest wall, the set pressure limit remains the same, but the delivered tidal volume fails
Pressure regulated volume control (PRVC)
volume and pressure control, delivered over a set time; constant pressure applied throughout inspiration regardless of whether breath is control or assist breath; vent will adjust pressure as needed r/t airway resistance and compliance changes
CPAP
spontaneously breathing pt; gives continuous positive airway pressure to keep alveoli open to maximize oxygenation
BIPAP
2 levels of positive airway pressure; inspiratory pressure (IPAP) would be a higher level and the pt would be given lower pressure during expiration (EPAP)
normal vent rate
12-20
normal tidal volume
5-7ml/kg
normal FiO2
40-100%
normal PEEP
5-10
high pressure alarm causes
anything causing vent to have to work harder to give the set volume; decreased lung compliance, increased secretions, bronchoconstriction, kinked circuit
low pressure alarm causes
something making it easier to give set volume than it should be; disconnection, significant airleak, extubation
minute ventilation
RR x TV
weaning off vent parameters
VC 10-15ml/kg
TV 7-9ml/kg
PaO2 greater than 60 on an FiO2 of less than 40%
extubation
HOB 75 degrees, hyperoxygenate, suction oral cavity, deflate and remove cuff, encourage to cough, suction PRN, monitor closely and encourage vocal rest, monitor ability to cough and swallow
vent recommendation with respiratory acidosis
increase respiratory rate to blow off the excess CO2
complications of mechanical ventilation
infection, positive fluid balance, pt discomfort, and psychosocial
benefits of sedation
decrease anxiety, amnesia, reduce tissue O2 consumption, improve vent synchrony
preventing VAP
hand hygiene, oral care, HOB 30-40 degrees, suction only PRN, cover yankauer cath when not used, adequate ETT cuff pressure, d/c NGT asap, subglottic suctioining prior to repositioning or deflating cuff
when to hold tube feedings
if residual more than 150cc
