PPV Flashcards
what is cerebral perfusion pressure
CPP = amount of blood perfusing brain
what two values equal CPP
mean arterial blood pressure - intercranial pressure = CPP
what does PPV do to ICP
increases
what does PPV do to MAP
decreases
what is normal cpp
88
to treat ptx with CPP what can you do
medically induced hyperventilation
when is medically induced hyperventilation good for
in emergencys like seizures and coughing
where should you keep MAP at
30 cmH2O or less
increased airway pressure increases what 4 things
increased MAP, intrapleural pressure, intrapulmonary pressure, intrathoracic pressure
what factors affect MAP
mode of ventilation, level of positive pressure, duration of insp & exp, nature of waveforms, level of PEEP, lung/thorax mechanism
VILI
ventilatory induced lung injury
VALA
ventilator associated lung injury
in normal lungs what amount of pressure is transmitted to the thoracic cavity
50%
how much deadspace is increased just bc pt is on a vent
40%-60%
what types of traumas can occur in the lungs from PPV
barotrauma/volutrauma
how often does barotrauma/volutrauma occur
5-15%
what is shearing
one portion inflates faster than others
tearing
overdistension
where should you keep PIP
less than 60
what things can happen as a result of barotrauma
pneumothorax, pneumomediastinum, pneumoperitoneum, etc
biotrauma
causes excessive stretching of alveolar cells
what does biotrauma cause
forms edema, releases inflammatory mediators and chemical mediators
vent factors that increase risk of barotrauma
large VT, high peak/mean pressure, high PEEP, long insp times, high FIO2, infections, aspiration
patient factors that increase risk of barotrauma
decrease compliance, increase resistance, pre-existing bullous DX, surfactant deficiency, host immunity, ARDS
what does auto peep increase
WOB and pulmonary vascular resistance
air trapping has what length of time constant
long length
in a pressure volume loop what does a flat top indicate
overdistending lung
how do you fix a flat pressure volume loop
decrease pressure or volume
T/F pressure in upper airway may not reflect alveoli pressure
t
how many ventilator pts develop lung infections
15-40%
where should you keep the head of bed
less than 30
commonly isolated pathogens - gram negative
pseudomonas, klebsiella, E-coli, influenzae
gram positive
staphlyococcus aureus, streptococcus pneumoniae
what does high concentrations of oxygen produce
oxygen free radicals
what detoxifies radicals
superoxide dismutase
what produces superoxide dismutase
type II cells
what does oxygen toxicity cause
decrease in: tracheal mucus flow, macrophage, VC, surfactant production, compliance, diffusion capacity, pul cap blood flow, cap injury, endothelial cell damage, absorption atelectasis
hemodynamic considerations increase
increased intrathoracic pressure, systemic blood volume
hemodynamic considerations decrease
pul blood flow, venous return, right vent stroke volume, pul arterial pressure, filing pressure, left vent stroke volume
how much blood do the kidneys recieve
25% of bodys circulating blood
what do volume receptors do
found within left atrium, sensing decreased volume,, which then signals increase in ADH, to stop urine output
what do baroreceptor stimulation cause
carotid bodies in aortic arch decreases CMO
what does low PAO2 effect on kidneys
decrease in urinary flow/function
what level of co2 has a big effect on kidneys
65
what level of o2 effects kidneys
below 40
what does plasma renin activity do
activates cascade to retain sodium and ater
where does blood flow redistribute in the kidneys
outer cortex decreases while inner cortex (juxtamedullary region) increases
what does blood flow redistribution lead to
more sodium, urine, and creatine being absorbed
what indications renal failure
oliguria <180 ml in 8 hours
increase BUN and creatinine
what is normal BUN (blood urea nitrogen)
10-20 mg/Dl
what is normal creatinine levels
0.7-1.5 mg/dl
diet changes bun or creatinine
bun
perfusion changes bun or creatinine
creatinine
what can decrease portal vein flow to the liver
drop in CMO and diaphragm moving into abdomen
indicators of liver dysfunction
prothrombin time >4 seconds
bilirubin level >50mg/L
albumin level <20g/L
what causes mucosal edema
blood being pushed out from the organs
in terms of ab considerations what can happen to bowel and stomach
swelling of bowels and stomach and bowel obstruction
what can make swelling in abdomen worse
peep
how many patients get ulcers caused by what
20% and stress
what type of diet can lead to higher co2
high carb diets
t/f vent slows wound healing
true
t/f copd pts have high caloric needs
true
what does induced hyperventilation do to the hemoglobin curve
shifts to the left causing less o2 to tissues and can cause hypoxia
how does induced hyperventilation interfere with cerebral tissue metabolism
reducing atp stores and 2,3 DPG levels
