7/5 ACE 2013 10B

4. Aldrete vs PADSS (Post anesthesia discharge scoring system)
Aldrete - Consciousness, BP, SPO2, Respiration, Activity (>9)
PADSS - N/V, pain, bleeding, activity, circulation, voiding? (>9)

7. Compazine or prochlorperazine is a dopamine blocker like metoclompramide
Phenergan or promethazine is a histamine blocker with dopamine antagonist effects

41. Even though neuraxial to high thoracic does not affect C3-5 of the phrenic nerve, it does affect expiratory effort. Thus, expect that tidal volume, RR, MV does not change. However, expiratory reserve volume, peak expiratory flow, and vital capacity are decreased.

45: Respiratory factors in pregnancy: lower FRC from uterus. Progesterone has opposite effects than opioids in terms of CO2 response and ventilatory drive so women breath deeper.  Progesterone is also a bronchodilator so dead space increases by 45%.

46: Foot drop after partuition is often 2/2 lumbosacral stretching from lithotomy position. Injury of the lateral femoral cutaneous nerve results in meralgia paresthetica and presents with sensory deficits in the anterolateral thigh. Obturator injury means no adduction of leg and decreased sensation to medial side of leg.

54: Umbilical arterial blood goes from fetal->mother so it reflects fetal respiration. Average values
PaO2 20-30, PaCO2 50-55, pH 7.2-7.3, bicarb 22-25. pH below 7.0 and base deficit of 12 should be considered definitive evidence of intrapartum asphyxia.
fetal scalp blood pH of more than 7.25 is normal, <7.2 means emergent c-section.

55. Stable monomorphic regular VT can be treated with adenosine now!

67. Laryngoscopy w/ intubation requries higher MAC than surgical incision

Extubation criteria
RR <35
Vital capacity > 10ml/kg
NIF > -20
Tidal Volume > 5ml/kg
MV < 10L/,min
Thoracic compliance > 25ml/cmH20

Diaphragm is the most resistant to paralyzation, reason unclear.
Orbicularis oculi approximates pharyngeal muscle blockade
Distal extremities (adductor pollicis) /abd muscles recovered the slowest from blockade

7/6 ACE 2011 8B x

9. Delayed clamping of umbilical cord in preterm babies decreases risk of intraventicular hemorrhage.  Sequelae IVH can result in life-long neurological deficits, specifically cerebral palsy, developmental delay, and seizures. PVH-IVH is diagnosed primarily through the use of brain imaging studies, usually cranial ultrasonography. Two major factors that contribute to the development of PVH-IVH are loss of cerebral autoregulation and abrupt alterations in cerebral blood flow and pressure. Incidence of PVH-IVH in infants of very low birth weight (< 1500 g) or infants of less than 35 weeks' gestation has been reported to be as high as 50%. most hemorrhages occur when the neonate is younger than 72 hours, with 50% of hemorrhages occurring on the first day of life. Presents with A sudden unexplained drop in hematocrit levels, Possible physical findings related to anemia (eg, pallor, poor perfusion) or hemorrhagic shock, A sudden and significant deterioration associated with anemia, metabolic acidosis, glucose instability, respiratory acidosis, apnea, hypotonia, and stupor is present. Treatment include Correction of anemia, acidosis, and hypotension, as well as ventilatory support, might be required in those neonates who present with acute deterioration. Serial lumbar puncture, although once used to prevent progressive hydrocephalus, is not indicated. Because most patients with hydrocephalus following PVH-IVH demonstrate spontaneous resolution within weeks of onset, surgical intervention is usually unnecessary. Ventriculoperitoneal and ventriculosubgaleal shunting remain the definitive treatments for posthemorrhagic hydrocephalus requiring surgical intervention.

12. Signs of bladder perf after TURB: hypotension, bradycardia, dilution of plasma from irrigation, restlessness, diaphoresis, hiccups. Spinal should be T9-10 as below may be uncomfortable and above may mask signs.

13. Newborn HR is 120. 1 month gold HR is 160. By 12 months, BP should be 90/60

Leukocyte reduction reduces alloimmunization, CMV infections, platelet transfusion refractoriness, nonhemolytic febrile reduction.


23. CO2 absorbers problems
Compound A - sevoflurane degrades in CO2 absorber (not liver) with baralyme rather than soda lime, low flow rather than high flow, higher temperature and fresher absorbent. Not shown to have clinical affect in humans.

CO is formed with degradation of all volatiles in CO2 absorber. Desflurane > en > iso >> sevo = halothane. More than dry baralyme in higher temp and lower gas flows. Happens mondays.

Fires with sevoflurane more likely with dry baralyme and soda lyme, first case of the day.

25. The statins inhibit p450, which can affect degradation of lidocaine. Also tumescent liposuction is due with SQ injection of very dilute lidocaine (.1%) up to 35-55mg/kg. Peak levels at 8 hrs.

26. Misoprostol associated with high risk of uterine rupture during VBAC



38. SIADH vs cerebral salt wasting:

SIADH
Serum [Na+] (mmol/L): 128
Serum Osmolality (mOsm): 270
Urine [Na+] (mmol/L): 40
Central Venous Pressure (mm Hg): 12

CSW (volume contraction)
Serum [Na+] (mmol/L): 128
Serum Osmolality (mOsm): 270
Urine [Na+] (mmol/L): 40
Central Venous Pressure (mm Hg): 4

44. Neonates have high chest wall compliance so they have increased work of breathing to push and pull their chest wall.

51. 2,3-DPG is decreased in preserved blood products

52. Refeeding syndrome causes hypokalemia, hypophos, hypoglycemia, hypomagnesemia

55. femoral nerve block vs PCA for knee arthroplasty - reduces morphine consumption, reduces pain scores with activity but not at rest. Does not reduce urinary retention.

63. Superficial cervical block for entarterectomy is better in all ways to deep cervical block except higher chance of Horner syndrome.

64. After aspiration, suction intubate and then bronch

76. Insulin requirements in pregnancy decrease in first trimester and increase in 2nd and 3rd. Mother experience great decrease in requirements after giving birth. Diabetics have bigger babies, more premature babies, more birth defects. Neonates are at risk for hypoglycemia.

Myotonic dystrophy causes muscle rigidity with succinylcholine. In advanced cases, it can cause hyperkalemia.


80. Burn victims have increased metabolic demand, third spacing, vascular permeability throughout their body and low output renal failure from prerenal. However they have decrease CO! Also keep body temp at 38.5!

81. Parkland formula is 4ml*kg*%burned.

82. LSD: include elevated temperature, hypertension, tachycardia, mydriasis, agitation, anxiety, increased production of saliva, hyperreflexia, hyperglycemia, and increased wakefulness.

85. Pulm HTN: Prevent and aggressively treat hypotension, Phenylephrine, vasopressin, and norepinephrine are recommended to treat hypotension, Maintain adequate preload and cardiac contractility, Prevent hypoxia, hypercapnia, acidosis.

continue drug therapy directed at decreasing PAP: prostacyclin (epoprostenol, treprostinil, iloprost), endothelin receptor antagonists (bosentan), phosphodiesterase-5 (sildenafil). Give CCB in pts response to vasodilators. Consider nitric oxide.

88. Acute Liver Failure mortality major cause is cerebral edema and increase in ICP. Pt do not have time to develop varices, hepatopulnonary syndrome. Tylenol causes metabolic acidosis. Possible renal failure and ARDS.

89. During the reperfusion phase of liver transplant, ICP can have fatal elevations. Dysrhythmias and hypotension can lead to cardiac arrest. Pulm HTN may worsen.

90. Inhalers: need to increase albuterol dose when intubated because it ahdheres to tracheal tubes. LMA decreases airway resistance than tracheal intubation. Propofol with metabisulfite causes increase in airway resistance than calcium edetate.

95. Airway laser/fire. All plastic tubes including red rubber and silicone are flammable. PVC is most, silicone is least. Cuff needs to be filled with water and double cuffed and metal tubes are better. Jet venitlation is most effective way to prevent airway fire as it avoids tracheal tube which is flmmable material. Risks of jet ventilation: barotrauma, pneumothorax, subcutaneous emphysema, and gastric distention.

7/3 ACE 2008 5A bx

If you can ventilate but cannot intubate a pregnant woman who is going for emergent c-section and the fetal VS are bad, then just continue mask ventilation while maintaining cricoid pressure. Do not do nasal intubation as pregnant women have friable nasal mucosa and may bleed. LMA or combitube is tempting but may cause aspiration in this event.

Mallampati score increases with pregnant and correlates with difficulty of intubation in pregnant women.

Ketorolac is relative contraindication to asthma.

Allergies in OR: 1. NMS, 2. Latex, 3. Abx

Corneal abrasion is NOT treated w/ patching. There is little to no evidence for abx or mydriatic drugs. There is great evidence for treatment of pain with NSAIDS.

7/1/14 - ACE questions 2008 5A bx

Helium has low density, which does 2 things. One, it lowers the reynold's number is more air travels laminar instead of turbulent. Two, it increases turbulent flow but doesn't work in the small airways where laminar flow predominates. It also decreases the work of breathing.

APGAR - appearance, pulse, grimace, activity, respiration

Myotonic dystrophy - muscles still contract after NMB and regional technique. Exaggerated responses to sux. Causes AV conduction problems.

Cerebral vasospasm after SAH - most common 1 week after SAH not 3 days. More likely with severity of SAH. Nimodipine not nifedipine is drug of choice. HHH therapy should be started after cerebral vasospasm occurs.

Apnea in neonates
   Risk factors: decreased postconceptional age, decreased gestational age, hx of apnea, presence of anemia
   Management: regional, avoiding opioids, longer term monitoring
   Postop management: stimulate the baby, metylxanthine (caffieine, theophylline), CPAP, correction of underlying metabolic diorders, PPV
   Avoid: Prostaglandin E1 which is used in ductal-dependent CHD but is associated with development of apnea

Herbal Medication
Garlic, ginseng, and ginkgo biloba inhibits platets (3G)
Ginseng also associated with hypoglycemia
St. John's wort is a MAOI, p450 inducer, decrease cyclosporin levels
Kava, Valerian are both GABA agonists and potentiate sedative medication


Antibiotic prophylaxis for
- prosthetic valve, prior IE, heart transplant w/ valvulopathy, partially fixed CHD
- for dental procedures, bronch biopsies, infected skin or tissue
- not for colonoscopy, bronch w/o biopsy, vaginal delivery, hysterectomy.
give ampicillin or ancef not gent or vanc

One lung ventilation

Open pneumothorax

• Awake
• Paradoxical respirations and mediastinal shift as air enters the pleural cavity
• Anesthetized
• PP ventilation reverses the above 2 effects

Lateral decubitus

• Awake
• Ventilation is matched to perfusion because the lower hemidiaphragm is more efficient in contraction + lower lung is more compliant
• 
• Anesthetized
• VQ mismatch as the reduction in FRC moves lower lung lower down the compliance curve
• 

One-lung ventilation

• Intrapulmonary shunt is decreased by HPV
• HPV is inhibited by abnormal PA pressures, abnormal venous pO2, hypocapnia, PNA, drugs: vasodilators, beta blockers, PDE-I, CCB, volatiles
• 
  

Neuro

• CP is not a risk for hyperkalemia after succinylcholine because acetylcholine receptors are not upregulated due to contractures
• For pts with MS, spinal anesthesia has been linked weakly to flareups so use epidural. 
• Lithium potentiates sux and non-depolarizing relaxants
• Pacemakers and epilepsy not contraindications to ECT
• 
  

• Sux and ALS - hyperkalemia 2/2 lower motor neuron involvement
• Sux and Duchenne's - high likelihood of MH and hyperkalemia
• Sux and Guillain-Barre syndrome - hyperkalemia
• Sux and Myotonic dystrophy - contractures making it hard to mask/ventilate
• Sux and Myasthenia Gravis - resistance
• Sux and Lambert Eaton - increased sensitivity
• Sux and MS - contraindicated if pt paretic

• In myotonic dystrophy, 4 concerns.
• contractures so no succinylcholine, neostigmine, and shivering (hypothermia)
• sensitivity to anesthetics, especially respiratory depressants
• aspiration risk
• possible MH

• Hypokalemic periodic paralysis vs Hyperkalemic
• Hypokalemic: Treat with diamox or spironolactone, avoiding carbs (insulin release), hyperventilation, alkalosis
• Hyperkalemic: treat with furosemide, carbs, calcium

http://www.aana.com/newsandjournal/Documents/p297-302.pdf

Comparing etomidate vs propofol vs thiopental for neuroprotection

Summary:
All three decrease ICP indirectly by decreasing CBF, which is directly decreased by reduction in CMRO2.

However, only etomidate exhibits properties where CBF and CMRO2 are decoupled. That is, etomidate decreased CMRO2 after CBF already reached a minimum. This may be good and bad depending on the goal. For example, inducing coma for poststroke may be bad with etomidate because increased BF with decreased metabolism means more oxygen lying around to develop free oxygen radicals.

Propofol seems to have anti-oxidant effects as in test animals, infarct size was smaller initially and animals had possibly better motor skills at day 21.

Brian waves/burst suppression/isoelectric
At sedative doses or at doses associated with excitation or disinhibition ("stage 2" anesthesia), median EEG frequency increases because alpha waves (7-13 Hz) typical of the awake state change to beta waves (13-30 Hz). As the depth of hypnosis increases, there is a decrease in frequency and an increase in amplitude (power) of the EEG waves. Surgical anesthesia is associated with an EEG characterized by a predominance of delta waves (0.5-3.5 Hz). Increasing the dose of thiopental further leads to burst suppression (characterized by alternating periods of delta waves and electrical inactivity) and, finally, a completely isoelectric ("flat-line") EEG.

IV Induction Agents

Thiopental: 4-7mg/kg, GABAa receptor positive allosteric  modulator (increase length that channels opens compared to benzos which increases frequency, aka efficiacy vs potency)

Special Properties:
- in subhypnotic dose, thiopental can be hyperalgesic (lowering pain threshold), can cause disinhibition and excitation

- acute tolerance: Early studies showed plasma thiopental concentration at awakening is proportional to the intubating dose rather than depth of anesthesia. The higher the induction dose, the higher the plasma levels at awakening. This was found to be not true in further studies and accounted for by studies that peripheral venous plasma thiopental concentrations poorly reflect brain (i.e., jugular venous) thiopental concentrations.
http://web.squ.edu.om/med-Lib/MED_CD/E_CDs/anesthesia/site/content/v02/020221r00.htm

- pH 10-11, long shelf life but precipitates NMBs, which come in acidic solutions

- Pain on arterial infection. DON'T DO IT because it extensive edema, gangrene, limb loss, and even death.

#Neuro
- See neuroprotection article. Basically thiopental is equal to etomidate and propofol.

#Resp
- decreases resp drive and airway reflexes. Airway responsiveness increases and this increased coughing and largynospasm more than other IV induction agents. Increases histamine circulation which can be bad for asthmatic.

#CV: unlike propofol, thiopental does not block sympathetic response and pts are more likely to become tachycardic with thiopental than propofol on inductoio

#Heme
- absolute contraindication in porphyrias. Thiopental induces CYP450 and delta-aminolevulinic acid (ALA) synthase, which builds up in pts with porphyria (downstream mutation). ALA is neurotoxic.

Propofol

Egg allergies to yolk (Lecithin) precludes its use.
Clearance is mostly hepatic but also extrahepatic, lungs play a role


#Neuro:
also acts on GABAa receptors. Also decreases CMRO2, CBP, ICP but may decrease CPP as propofol decreased MAP more than thiopental. (CPP=MAP-ICP). Does not produce hyperalgesia in sedative doses like thiopental. Has some amnestic qualities in sedative doses as well. Antiemetic effect as well.

#Resp:
Decreases vent drive, profound in COPD pts. Incidence of wheezing is lower with propofol than etomidate of barbituates.

#CV:
Profound hypotension from decreased preload (lower SVR), decreased afterload (cardiodepressant), and decrease baroreceptors and sympahtetic reflexes. More than thiopental

Fospropofol is a prodrug that is metabolized by alkaline phsophatase to form propofol, phosphate, and formaldehyde. Supposed to cause less pain in IV, less hyperlipidemia, and less risk of bacterial infection.

Etomidate
0.2-0.5mg/kg

- activates GABAa receptors and also some possible disinhibiting of extrapyramidal system causing myoclonus 40% of the time.
- dissolved in propylene glycol, which causes pain on injection

Ketamine
1-2mg/kg

#Neuro
- dissociates thalamus from limbic cortex causing dissociative anaesthesia
- elevates ICP, CMRO2, CBP but new research shows this may not be true when combined with benzos

#Resp:
Ketamine in USA is a bronchodilator and sialagogue. However, the S enantiomer found in Europe is the more potent version of ketamine and does not bronchodilate. Does not depress vent drive much

#CV
- cardiodepressant but potent stimulator of the sympathetic system. Increases HR, BP, and myocardial demand. Bad for CAD but may be good for shock.
- spinals or sympathectomies unmask the cardiodepression