Basic2 Flashcards
Contraindications for CSE
patient refusal, sepsis, hypovolemia, coagulopathy or therapeutic anticoagulation, elevated ICP, infection at site
dose for caudal in infants
CSF volume per percentage of body weight is greater in infants than adults. Need a comparatively larger doses per kg of LA
Caudal in infants
heart rate is preserved better due to poorly developed parasympathetic activity
-infants rely more on diaphragmatic contribution due to more compliant ribs and loss of intercostal muscles with high spinal
epidural test dose
3 ml of lidocaine 1.5% with epinephrine 1:200000
- lidocaine tests for intrathecal placement: detectable sensory block 1-2 minutes with motor 3-4 minutes
- Intravascular: lidocaine will cause dozziness, tinnitus, circumoral paraethesia, metallic tase and blurred vision
- Epinephrine will cause sudden tachycardia (>10bpm) and HTN (>20mm Hg change), some will report palpitations and headache
TNS (transient neurologic syndrome)
possible that pregnancy can decrease incidence
epidural test dose during contractions
need to perform test dose between contractions to not be confused about increases in HR and HTN
- also concern for decreased uterine blood flow with epinephrine
High spinal
1) sudden and profound BP drop :vasodilation from sympathetic nerves
2) hypotension can cause nausea and vomitting
3) Accessory muscles of respiration are blocked decreasing TV
4) cardiac accelerator fibers are block; severe bradycardia
5) diphragm can be blocked
6) if spreads to brain unconciousness is assured
complications of neuraxial
- high spinal or intravascular injection
- infection: from superficial skin to life threatening epidural abscess
- epidural hematoma: pressure applied to spinal cord or nerve root resulting in ischemia and possible irreversible nerve damage
- arachoiditis (rare) due to inappropriate drug causing inflammation: various neurologic deficits such as paraplegia, quadriplegia, hydrocephalus, syringomyelia
post dural puncture headache
- reduction of the buoying effect of CSF on brain, causes traction and stretching of the meninges as the patient assumes the upright position
- improved with recumbency
- tx: fluids, caffeine, NSAIDs, narcotics and or epidural blood patch
Heparin MOA
binds to antithrombin with high affinity and subsequently inactivate thrombin (IIa), factor Xa, and factor IXa
Warfarin MOA
interferes with Vit K dependent clotting factors ( II, VII, IX, X)
Fondaparinux
inhibits factor Xa
Risk factors for awareness
C section, Cardiac surgery, emergent surgery, trauma, RSI, TIVA, difficult intubations, history of substance abuse, ASA 4 or 5, history of awareness
Auditory Evoked Potential Monitor
electrical responses of the brainstem, auditory radiation and auditory cortex to auditory sound stimuli (clicks)
- analyze the AEP wave form (latency and amplitude) to generate an AEP index that correlates to anesthetic concentration and level of consciousness.
Flexible fiberoptic intubation
nasal or oral
- pt selection (psychological preperation), anxiolytic, anti-sialagogue
- numbing
awake nasal intubation requires which additional nerve blocks
greater and lesser palatine and anterior ethmoid nerve
- plus the glossalpharyngeal and superior laryngeal nerve
- afrin or phenylephrine should be used to minimize bleeding risk
absolute indications for one-lung ventilation
- massive bleeding in one lung
- infection in one lung
- bonchopleural/bronchocutaneous fistula
- lung bullae
- alveolar lavage
- minimally invasive cardiothoracic surgery
lung with upper lobe coming of on average 1.5 cm from carina
right
Bronchial BLockers
- ideal if only single lumen is achievable
- more susceptible to displacement
- not optimal lung deflation
- difficult to place
- dislodge
- difficult to suction secretions
Lighted stylet
- blind approach; watcht he pretracheal glow as you advance
- as you advance a localized glow indicated a tracheal intubation vs a diffuse indicate esophageal
- contraindications too much skin to properly see the light (obesity), skin pigmentation issues, airway tumors/infections/trauma/foreign bodies (blind approach)
pediatric ETT size
ID= (age/4)+4
size of ETT
millimeter of internal diameter
cuffed tube
> 6 years old
Evaporative fluid losses
minimal surgery (laproscopic) 0-2 ml/kg
moderate (open chole) 2-4 ml/kg
severe (open bowel) 4-8ml/kg
Corneal abrasions
GA induces lagophthalmos (lid not closing all the way) and inhibits Bells phenomenon (eyeball turns up whilst sleeping- protective measures)
Post op vision loss
Most common after spinal fusion or cardiac surgery or long steep T-burg cases
-male sex, obesity, diabetes, use of wilson fram, EBL >2L, case >4-6 hours, BP 40% lower than baseline for >30 minutes
Ischemic optic nerve neuropathy
anterior; central retinal artery and small branches of ciliary artery
posterior: small branches of ophthalmic and central retinal arteries
- both because of ischemia
- increased venous pressure can cause perfusion of optic nerve
Anterior Ischemic optic neuropathy
- infarcts of the watershed perfusion zones between the small branches of the short posterior ciliary arteries
- cardiac surgery, hemorrhagic hypotension, anemia, head and neck surgery, cardiac arrest, hemodyalisis
Posterior Ischemic Optic Neuropathy
- more common
- Prone posterior spinal fusion cases, steep T burg
- decreased O2 delivery to the posterior portion of the optic nerve between the optic nerve and the point of entry to central retinal artery
- more frequent in healthy ASA 1-2
Cortical blindness
after profound hypotension or circulatory arrest
- infarcts in parietal or occipital lobes
- loss of vision but retention of pupillary reactions to light
Retinal artery Occlusion
- pale edematous retina on exam
- emboli or intranasal alpha adrenergic agonist
- stellate ganglion block can help
Venous Air Embolism
- surgery where operational site is higher than heart ( sitting neuro is the most, but thoracotomy, open vessels, cesarean sections -when uterus is out
- depends on volume of air entrapment and rate of accumulation
- 2-5 ml/kg is lethal dose
- large can cause a gas air-lock causing complete R ventricular outflow obstruction
- PFO can cause cerebral air embolisms
symptoms of VAE
cardiovascular pulmonary and neurologic
Cardiovascularly: tachy, ST changes, CO drops, BP drops
Pulmonary: dyspnea, coughing, lightheadedness, CP, decrease ETCO2, SaO2, PaO2 with hypercarbia
-Neuro: stroke with PFO
Monitoring for VAE
- TEE is most sensative
- Precordial doppler: R or L sternal border at 2-4 intercostal space: normal washing machine turbulence changes to erratic high-pitched swishing, progresses to “mill wheel” murmur
- transcranial doppler if PFO
- PA catheter: insensitive
- End tital Nitrogen: most sensative, 30-90 seconds before ETCO2 changes; not useful if nitrous is being used
- ETCOs: change of 2 mm Hg can indicate
- Vigilance
Management of VAE
-tell surgeon
-flood operation site with saline or wax
- optimize position (left lateral decub or t-burg)
-ACLS
-aspiration from catheter is only 6% effective
-optimize myocardial perfusion
- inotropic support
hyperbaric O2 therapy can be beneficial
Intraarteral injections
- leads to cyanosis, gangerene, loss of limb ect.
- signs of accident arterial are pulsatile flow, blood in the IV tubing palpable pulse proximal, signs of ichemia distal to catheter, worse pain than expected
- worse of benzo, barbs or vasoconstrictors.
- leave catheter in to flush out area/confirmation of arterial injection
- anticoagulate
- elevation, warms, massage
- LA can help reduce vasoconstriction
- stellate ganglion block or regional
- papaverine can induce smooth muscle relaxation
N2O cylinders
- Reads 745 PSI till 80% gone
- roughly 250L left when pressure begins to fall
- full tank hold roughly 1590L of N2O
first stage
allows preferential use of the pipeline oxygen when the higher pressure in this system is sensed. The oxygen cylinder tanks enter at a lower pressure
lowest pka for opioids
alfentanil
infared spectometer
- measures CO2
- Cannot measure O2
- End-tidal CO2 (ETCO2) is measured by infrared spectrophotometry where a wavelength of infrared light is passed through a gas sample and the amount of energy detected is inversely proportional to the gas partial pressure
most effective PONV med for children
Zofran
aprepitant is close but requires long onset time
AV nodal blockade due to stenosis
PDA
drugs that reduce ketamine emergence delerium
Benzodiazepines, propofol, and barbiturates
Cytochrome P450
Cytochrome p450 is a heme protein that utilizes molecular oxygen to oxidize organic compounds
pRBCs over time
acidemia, decreased 2,3 DPG and increase K
Myocyte action potential
4: resting
0: Na in (jump up)
1: K, CL out (dip down)
2: Ca in K out (plateau)
3: K out (drop down)
“nine Koala cause Kookiness” (sodium in k out ca out k out)
sub-ambient pressure alarm
- alarm is triggered when the pressure in the breathing circuit falls below atmospheric pressure by a pre-determined amount (typically below -10 cm H2O)
- Suction in the trachea
- Patient inhalation against an increased resistance in the circuit
- Patient inhalation against a collapsed reservoir bag
- A malfunctioning active closed scavenging system (excessive vacuum or valve dysfunction)
- A blocked inspiratory limb during exhalation
angiotensin II effect on GFR
Angiotensin II causes efferent glomerular arteriolar vasoconstriction which will maintain or increase glomerular filtration rate (GFR) in states of hypovolemia.
Propofol guidelines
- bacterial protection for 12 hours after opening (most recommend 6-8 hours, truelearn 12)
- dont mix it with other drugs
Desflurane effects
Desflurane primarily decreases arterial pressure by decreasing afterload. Desflurane increases heart rate, particularly when the concentration is quickly increased, and also causes dose-dependent depression of myocardial function. Cardiac output is maintained and there is no significant effect on left ventricular diastolic function.
LEast stable factor in FFP
VIII and V
- VIII interacts with vWF
Post operative cognitive delay
advancing age, lower educational level, and a history of previous cerebral vascular accident with no residual impairment.
Vapor pressure
- pressure exerted by the vapor when in equilibrium with the solid/liquid
- desflurane > isoflurane > sevoflurane
- Vol = FGF * Pvap / (Pbar - Pvap)
amount of fibrinogen in cry
Cryoprecipitate contains approximately 200 mg/unit of fibrinogen
Lorazepam premedication
Lorazepam premedication does not significantly improve patient satisfaction and can prolong extubation time, particularly in shorter cases
myocardial ischemia
- st elevation is transmural
- ST depression is subendocardial
K sparing diuretics
“The K+ STAys,” for Spironolactone, Triamterene, and Amiloride.
Anticholinergic syndrome
hyperthermia, tachycardia, blurry visions, dry skin, urinary retention
Cholinergic poisoning
Diarrhea, Urination, Miosis, Bradycardia, Bronchospasm, emesis, lacrimation, lethargy, salivation
Bronchospasma pathophysiology
noxious stimuli ->afferent sensory fibers in vagus->neurons in nucleus of the solitary tract->efferent fibers through vagus->bronchial smooth muscles-> released Ach bind to M3 muscarinic receptor->increased C GMP->bronchial smooth muscle contraction
Pharmacological causes of bronchospasm
desflurane B blockers NSAIDS cholinesterase inhibitors (neostrigmine) histamine releasing drugs (atracurium, mivacurium, sodium thiopental, morphine)
Signs of bronchospasm
rapid increase in peak airway pressures
decreased exhaled TV
shark finnig capnograph
Auto peep can occur
Bronchospasm management
increase O2 to 100%
increase anesthetic depth ( sevo and iso can bronchodilate
manual ventilate for tactile knowledge
B2 adrenergic agonists (albuterol)
magnesium can be beneficial for asthmatics
Epinephrine 10 mcg IV
Hypersensativity reactions
1) anaphylactic IgE mediated: anaphylaxis, allergic rhinitis, asthma
2) classic compliment system, IgG and IgM; ABO incompatability, HIT
3) immunce complxes of antigens and antibodies; serum sickness
4) delayed hypersensitivity, proliferaation of cytotixic T lymphocytes; GVH, tuberculin immunity
Anaphylaxis
-cross linking of IgE causes basophils and mast cell degranulation
-release of inflammatory markers; prostaglandins, leukotrienes, histamine and typtase
Signs: hypotnesion, tachy, bronchospasm, edema, hypoxia, rash
Causes of anaphylaxis
- # 1 NDNMB (though evidence of suggamdex is rising)
- B lactam antibiotics (PNC, cephalosporins)
Management of anaphylaxis
- discontinue drug
- 100% O2
- Volume expansion
- Epinephrine 5-10 mcgs (alpha causes vasoconstriction, B bronchodilation, stabalizes mast cells)
- admit to ICU for 24 hours
Laryngospasm
More common in kids and ENT surgery
- muscles are the lateral cricoarytenoids, the thyrorytenoids and cricothyroid
- causes by stimulus on oropharync; tube, secretions, blood
Treatment of laryngospasm
- 100% O2 with CPAP or PEEP
- jaw thrust
- larsons manuever
- deepen anethesia or sux (0.5-2 mg/kg)
Risk factors for aspiration
abdominal /GI surgery, strokes (swallowing dysfunction), diabetes, bowel obstruction, prego, old, GETA
Bad outcomes for aspiration
volume of 0.4 ml/kg and a pH less than 2.5
H2 agonists
bind to histamine receptors on the gastric parietal basal cells that produce gastric production
-ranitidine and famotidine
PPI
- block H+/K+ ATPase on the acidic luminal side of the gastric parietal cells
- -prazole
Antacids
only decreasae current acid in stomach
- use nonparticulate materials
Cricoid pressure
44N
Interscalene Block
- Brachial plexus at the level of roots/trunks
- shoulder and upper arm procedures
- side effects; stellate ganglion, phrenic nerve, recurrent laryngeal nerve, peumothorax
- Horner syndrome with stellate ganlgion ( ptosis myosis and anhidrosis
Supracavicular nerve block
- brachial plexus at level of trunks
- elbow, wrist and hand surgery
- highest incidence of pneumothorax
- can get stellate ganglion, phrenic and RLN
Infraclavicular nerve block
- brachial plexus at level of cords
- wrist and hand