Chapter 16 - Critical Care II Flashcards
Diagnosis for significant organ failure of lung?
need for meghanical fentilation
PaO2/FiO2 ratio <300 for 24 hours
Diagnosis for significant organ failure of cardiovascular?
need for pressors to maintain adequate tissue perfusion
Or
Cardiac Index <2.5
Diagnosis for significant organ failure of kidney?
creatinine >2x baseline on 2 consecutive days
OR
dialysis
Diagnosis for significant organ failure of Liver?
bilirubin >3 on 2 consevutive days or PT>1.5 control
Diagnosis for significant organ failure of CNS?
glasgow coma scale <10 without sedation
Diagnosis for significant organ failure of coagulation?
platelets <100
need for factor replacement
Diagnosis for significant organ failure of host defenses?
WBC <1000
OR
invasive infection including bacteremia
aspiration of what causes injury?
pH,2.5 and volume >0.4cc/kg causes incrased damage
what is Mendelson’s Syndrome?
chemical pneumonitis from aspiration of gastric secretions
most common site is posterior portion of RUL and superior portion of RLL
What is atelectasis?
bronchial obstruction and respiratory failure main causes
most common cause of fever in first 48h
fever tachycardia
increased in pts with COPD, upper abdominal surgery
tx with incentive spirometer
What can throw off pulse ox?
nail polish dark skin low-flow states ambient light anemia vital dyes
What causes pulmonary vasodilation?
bradykinin
PGE1
prostacyclin
NO
What causes pulmonary vasoconstriction?
histamine serotonin TXA2 epinephrine norepinephrine Hypoxia acidosis
how do you alkalosis via lungs?
pulmonary vasodilator
how do you treat acidosis via lungs?
pulmonary vasoconstrictor
what drugs cause pulmonary shunting?
Nipride
nitroglycerin
nifedipine
What is the most common cause of postoperative renal failure?
hypotension
What percentage of nephrons need to be damaged before you have renal dysfunction?
70%
What is FeNa?
urine NA/urine CR X plasma Na/urine Cr
what are the findings in prerenal acute renal failure?
FeNa 20
urine osmolality >500mOsm
otherwise consider renal cause
What do do with oliguria?
1st- make sure patient is volume loaded
2nd- try diuretic trial
3rd dialysis if needed
What are the indications for dialysis?
fluid overload increasing K metabolic acidosis uremic encephalopathic uremic coagulopathy poisoning
What is the benefit of CVVH?
slower
good for ill patients who cannot tolerate volume shifts
Hct increases by 5-8 for each liter taken off
What are the advantages of intermittent hemodialysis?
lower risk of systemic bleeding
facilitates transport for other interventions
more suitable for severe hyper K
lower cost
What are the disadvantages of intermittent dialysis?
availability of dialysis staff more difficult hemodynamic control inadequate frequency fluid control nutrition issues not good for increased ICP no removal of cytokines complement activation
what are the benefits of continuous renal replacement therapy?
better hemodynamic stability fewer cardiac arrhythmias improved nutritional support better pulmonary gas exchange better fluid control
disadvantages of continuous renal replacement therapy?
vascular access problems higher risk of systemic bleeding long term immobilization more filter problems cost
What causes release of renin?
decreased pressure sensed by juxtaglomerular apperatus
increased NA sensed by macula densa
beta adrenergic stimulation
hyperkalemia
What does renin cause?
converts angiotensinogen (from liver) to angiotensin I ACE converts angiotensin I to II Adrenal cortex releases aldosterone in response to angiotensin II
Where does aldosterone act?
distal convoluted tubule.
Reabsorbs more water by increased Na/K
ATPase on membrane- potassium secreted
What are other effects of angiotensin II?
vasoconstricts increases HR contractility permeability glycogenolysis gluconeogenesis inhibits renin
What is atrial natriuretic peptide?
released from atrial wall with dilation
inhibits Na and water resorption in the collecting ducts
vasodilator
What is ADH
vasopressin. released by posterior pituitary gland when osmolality is high
- acts on collecting ducts
- vasoconstrictor
What part of kidney controls GFR?
efferent limb
How are NSAID’s nephrotoxic?
inhibit prostaglandin synthesis resulting in renal arteriole vasoconstriction
How are aminoglycosides nephrotoxic?
direct tubular injury and later renal vasoconstriction
How is myoglobin nephrotoxic?
direct tubular injury
tx by alkalinizing urine
How is contrast dye nephrotoxic?
direct tubular injury
premedicate with fluid, N-acetylcysteine
What precludes dx of brain death?
uremia temp <70/40 desaturation with apnea test phenobarbitol/pentobarbitol metabolic derangements
What must you have for brain death?
must exist for 6-12 hours unresponsive to pain absent caloric oculovestibular reflex absent oculocephalic reflex \+ apnea test no corneal reflex/gag reflex fixed/dilated pupils EEG- electrical silence or MRA **Can still have deep tendon reflexes
What is the apnea test?
disconnect from ventilation
CO2>60 or increase >20 is positive
if arterial pressure drops to <60 or desaturates, test terminated
How is carbon monoxide dangerous?
falsely increase O2 sat reading on pulse ox
binds hemoglobin directly
can usually correct with 100% O2on ventilator
Abdnormal carboxyhemoglobin is >10%, >20% in smokers
What else can cause methemoglobinemia other then CO?
nitrites
tx with methylene blue
What is the order of clinical illness polyneuropathy?
motor>sensory
occurs with sepsis, can lead to failure to wean from vent
What does xanthine oxidase do? where is it from?
in endothelial cells, forms toxic oxyten radicals with reperfusion
also involved in metabolism of purines and breakdown to uric acid
DKA sx?
nausea, vomiting, thirst, polyuria
abdominal pain, increased glucose, increased ketones, decreased Na, increased K
tx w bicarb for pH>7.25
EtOH withdrawal?
HTN tachycardia delirium seizures Tx: thiamine, folate, Mg, K, B12, ativan
ICU psychosis?
generally occurs after third post op day, preceded by lucid interval
need to rule out metabolic and organic causes
