Jensen1 Flashcards
Bodies response to removal of carotid bodies
little change to ventilation at rest, response to hypoxia is lost and there is a 30% reduction in ventilatory response to CO2
chemoreceptors that mediate hyperventilation after carotid and aortic body denervation are located where
medulla oblongata - medullary chemoreceptors
PEEP effects (pulmonary)
prevent alveolar collapse, promote gas exchange, increases FRC, increases lung compliance, decreases intrapulmonary shunt, increases PaO2, increases dead space
PEEP effects (cardiac)
high airway pressure 2/2 to decreased pulmonary compliance can decrease CO - decreases ventricular filling, decreased coronary blood flow
PEEP complications
decreases CO, causes fluid retention (depresses ANF, increases ADH), increases pressure in SVC - can increase ICP, barotrauma
PEEP recommended for? not recommended? no evidence?
recommended for pulmonary edema, not recommended for localized lung disease (over-distends normal lung and redirects blood to diseased area, creating V/Q mismatch), no evidence that it increases incidence of ARDS, beneficial routinely, or decreases mediastinal bleeding
Eaton-Lambert definition
muscular weakness because of decreased release of acetylcholine 2/2 destruction of pre-synaptic voltage gated Ca channels by IgG antibodies
Eaton-:Lambert presentation and associated diseases
bronchial CA (oat cell), SLE, thyroid disease, present with dry mouth, proximal muscle weakness, muscle pain, weakness improves with exercise. more in men, sensitive to all NMBD
Eaton-Lambert treatment
excision of cancer, 4-aminopyridine (immunosuppressant) stimulates release of pre-synaptic acetylcholine, acetylcholinesterase is not effective
Increased mixed venous
left to right shunt, high cardiac output, cyanide poisoning, CO poisoning, methgb, hypothermia (decreased O2 consumption), sepsis, sampling error (permanently wedged PAC)
decreased mixed venous
increased O2 consumption (fever, thyroid storm, MH), decreased O2 delivery (hypoxia, decreased CO, decreased Hgb, abnormal Hgb)
mixed venous normal values
O2 40 mm Hg, CO2 45 mm Hg, 65-75% sat
shivering, mechanism and treatment
when preoptic region of hypothalamus is cooled, increases metabolic heat production up to 600%, increases O2 consumption and CO2 production, hypoxia inhibits shivering response, treatment with meperidine - decreases the shivering threshold
amide locals metabolism dependent on…
liver which is dependent on hepatic blood flow (decreased with NE, propranolol, GA) and extraction capacity (decreased with HF, cirrhosis, hypothermia)
ester locals metabolism dependent on…
pseudocholinesterase - low in renal failure, severe hepatic failure, pregnancy
which anticholinergic crosses BBB
scopolamine and atropine
Cholinergic (parasympathetic) crisis
SLUDEBBP - salivation, sweating, lacrimation, urination, defecation, erection, bradycardia, bronchial constriction, pupillary constriction
anticholinergic crisis - central anticholinergic syndrome
atropine and scopolamine because cross BBB, treatment is physostigmine; symptoms are fever (blocks sweating), blurred vision, photophobia, tachycardia, restlessness, somnolence
Horner’s syndrome
ptosis, miosis, anhidrosis, enophthalmos, flushing of conjunctiva and skin, nasal congestion (engorged blood vessels)
O2 consumption decreases with 1 degree centigrade
10%
oculocardiac reflex pathway
afferent: ciliary ganglion to ophthalmic division of trigeminal nerve (V), through Gasserian ganglion to sensory nucleus of the 4th ventricle, efferent: vagus nerve –> bradycardia, hypotension, PVCs
Phase II block characteristics
fade with twitch and tetanus, TOF <0.7 (T4/T1), post-tetanic potentiation
minimum fresh gas flow
150-500 ml/min for metabolic demands and replace anesthetic gas
advantages/disadvantages of closed circuit
ad: conservation or heat/humidity, economical, low pollution; dis: anesthetic concentration cannot be changed quickly and delivered anesthetic concentration uncertain, uptake of nitrous oxide can decrease O2