14 - Anesthesiology principles & pain management Flashcards by Guy Schachter

What are the 4 categories of drugs used in anesthesiology?

inhalators (maintenance)
hypotonic IV (induction)
analgesia 
muscle relaxation (paralytica)

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The goal of inhalator drug to to provide fast __ which is non __ and clears out quickly.

induction

toxic

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Blood-gas solubility coefficient is a measure of the drug’s __ to the __.

uptake

blood stream

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Less soluble inhalator drugs (__/__) lead to faster __ and __.

N2O/desflurane
induction
clearance

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More soluble drugs inhalator (__) clear more __.

halothane

slowly

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MAC measures the concentration needed to prevent __ due to __ in 50% of patients.

movement

surgical incision

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The higher the MAC, the __ potent the drug is.

less

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Examples for inhalator MAC:
Halothane-
Desflurane-
N2O-

0.75%
6%
104%

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Pungency of an inhalator may lead to __.

respiratory irritant

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Mention 2 low pungency drugs used for induction:

halothane

desflurane

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N2O is used for fast __ when combining with another inhalator.

induction

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What are the advantages of N2O?

minimal effect on respiratory/hemodynamic status

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What are the disadvantages of N2O? 2

Not good for maintenance

increased ventilation pressure/volume

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What are the C/I for N2O? 4

pneumothorax
SBO
auricle surgery
retina surgery

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What is the most common inhalator used for induction?

isoflurane

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Isoflurane is not used for __.

induction

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Isoflurane is better than ___ since it decrease less __, and has __.

halothane
CO
minimal metabolism

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Isoflurane is less sensitive to the __ effect of ___.

arrhythmogenic

catecholamines

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What are the disadvantages of isoflurane? 3

tachycardia (requires monitoring)
increases ICP in high dosage
high pungency

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Sevoflurane is an effective __ inhalator.

induction

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What are the advantages of sevoflurane? 4

low solubility
less pungency
no CV effect

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Which patients are likely to be inducted with sevoflurane? 4

children
bronchospasm
outpatients surgery
mask induction (for difficult airway)

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Desflurane is not used for __.

induction

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What are the advantages for desflurane: 2

fast effect

fast clearance

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What are the disadvantages of desflurane? 3

high potency tachycardia HTN

What are the main hypotonic drugs used for induction? 4

midazolam (dormicum) ketamine etomidate propofol

Dormicum is a __ acting __ with __ T1/2.

fast benzodiazepine short

Midazolam leads to __ and anti __ effect. It does not have __ effect.

amnesia anxiety analgesic

Since dormicum has minimal ___ effect, it is good for __ surgery.

cardiac | heart surgeries

Midazolam can cause __.

hypotension

Ketamine has a strong __ effect.

analgesic

Ketamine does not cause __ decrease, but if there is symptomatic tonus (__), it may lead to __.

hemodynamic hemorrhagic shock hypotension

In patients with maximal symptomatic tonus (__/__ shock) ketamine dosage should be __ by __% of normal dosage.

septic/hemorrhagic decreased 20

Ketamine is the drug of choice for patients with __ since it does not decrease __.

hypovolemia | BP

Ketamine is the drug of choice for patients with __, since it causes __.

asthma | bronchodilation

What are the disadvantages of ketamine? 5

``` increases symptomatic tonus (increased ICP) tachycardia HTN bronchodilation dissociative effect/delirium ```

Ketamine is not recommended for patients with __ disease, as it can cause heart __.

coronary | ischemia

What are the C/I for ketamine? 3

abdominal surgery coronary disease increased ICP

Etomidate is a __ agonist with __ effect and no __ effect.

GABA fast analgesic

What are the indications for etomidate?

trauma hypovolemia (2nd line) coronary disease (GS)

Why etomidate is good for trauma?

has minimal CV effect

What are the disadvantages of etomidate?

local pain myoclonus decreased ICP adrenal inhibitor

Propofol is a __ agonist with __ effect and no __ effect.

GABA fast analgesic

Propofol is a good __ drug.

maintenance

What are the indications for propofol? 3

``` short sedations (endoscopy) asthma (causes bronchodilation) no NV (nausea/vomiting) ```

What are the disadvantages of propofol?

``` local pain (we add lidocaine) fast hypotension due to vasodilation ```

Which patients would not be recommended propofol?

hypovolemic | coronary disease

Asthma patients should be inducted with: 2

ketamine | propofol

Renal failure patients should be inducted with: 3

ketamine propofol etomidate

Cardiac patients should be inducted with: 2

midazolam (dormicum) | etomidate

Remember that __ is the only induction drug that increase ICP, while the rest decrease it.

ketamine

What are the advantages of using analgesic drugs? 4

reducing MAC for inhalators mask the tachycardia/HTN caused by ventilation allow easier waking can be used as anesthetic if used in X10-20

What are the disadvantages of using analgesic drugs? 3

hypoventilation hypnosis amnesia

What are the 4 types of analgesic drugs?

fentanyl morphine pethidine tramadol

Fentanyl is a very __ drug with __ effect, lasting for _-_ minutes.

potent fast 20-30

Fentanyl is used as __ analgesic.

maintenance

What is the antidote for fentanyl?

naloxone

Morphine is used more for __ operative pain.

post

What is the antidote for morphine?

naloxone

Morphine starts effecting within __, and last for _-_ hours.

minutes | 3-4

Tramadol has a strong __ effect, and should be administrate in a __ together with _/_. Used mostly for __ pain.

emetic slow drip zofran / pramin postoperative

What are the two groups of muscle relaxing drugs?

``` depolarizing (non-competative) non depolarizing (competitive) ```

__ is a depolarizing drug.

succinylcholine

Succinylcholine is indicated for __ intubation. The effect lasts for _ minutes.

fast | 5

Before using depolarizing drugs, make sure the patient can be ventilated with a __, incase the __ fails.

mask | intubation

Which patients are more difficult to ventilate with a mask? 2

``` obese jaw malformation (micrognathia) ```

What are the disadvantages of succinylcholine?

bradycardia (more in children) hyperkalemia (more in burn/RF/trauma/paraplegia) malignant hyperthermia (more in myopathy/family history/children) muscular pain

What are the two competitive neuromuscular blockers drugs commonly used?

rocuronium | vecuronium

What are the indications for non depolarizing drugs?

easy intubation | maintenance

What are the disadvantages of non depolarizing drugs?

dose adjustment in RF can mask lack of analgesia (paralyzed but feel pain) myopathy and neuropathy

What is the antidote of rocuronium? what should it given with?

neostigmine | atropine

Why do we give atropine together with neostigmine?

to avoid arrhythmia/asystole

If using rocuronium, at the end of the surgery we must give ___ (__).

antidote | neostigmine

What is TOF (train of four)?

quantitative measurement determining the depth of anesthesia and level of neuromuscular paralysis

If there are 4 TOF twitches the level of block is __ and only then it is safe to __.

0 | extubating

``` Describe what percentage of receptors are blocked at each twitch disappearance: loosing the 4th -__% loosing the 3th -__% loosing the 2th -__% loosing the 1th -__% ```

75% 80% 90% 100%

What is the TOF ratio?

the ratio between the intensity of the 4th twitch and the 1st

At what TOF ratio can you safely extubate?

>0.9

What is percentage of oxygen saturation do we ventilate?

30-35%

When should we use arterial line to monitor BP during surgery? 5

* predicted hypotension/extreme changes during surgery * surgeries with hemodynamic effect (hepatic/trauma) * a need for frequent ABG *

Where would you insert an arterial line? 2

radial artery | axillar artery

Which surgeries may have high hemodynamic effect on the patient- requiring arterial line BP monitoring? 6

``` hepatic surgeries (e.g. Whipple) trauma/MOF cardiac morbidity pheochromocytoma carotid surgery difficult external monitoring (obesity/burn) ```

Which patients are most sensitive to temperature loss during surgery? 2

children | burn patients

Which disorders may occur due to hypothermia? 5

``` coagulopathy SSI (surgical site infection) ischemia induced by stress arrhythmia apnea ```

What does end tidal CO2 measure?

the maximum concentration of CO2 in the airway at the end of expiration

Using EtCO2 is the GS for locating where the __ is and as a measurement of the heart __ and __.

tracheal intubation perfusion production

What is the normal EtCO2? _-_ mHg

35-45

Increased EtCO2 (hypoventilation) may suggest increased:

BP metabolic rate hyperthermia (malignant hyperthermia)

Increased EtCO2 (hypoventilation) may suggest decreased:

respiratory rate | tidal volume

Increased EtCO2 (hypoventilation) may also suggest: 2

thyroid storm | sepsis

Decreased EtCO2 (hyperventilation) may suggest increased: 2

respiratory rate | tidal volume

Decreased EtCO2 (hyperventilation) may suggest decreased: 3

BP tidal volume metabolic rate

Decreased EtCO2 (hyperventilation) may also suggest: 3

hypothermia bronchospasm massive PE

How can we get a general sense of intravascular volume and renal perfusion during surgery?

urine catheter

What do we use to evaluate the filling pressure of the right heart after fluid administration?

CVP

Where would a CVP be inserted? where should it be placed?

above diaphragm main veins (subclavian, brachial, jugular veins) entrance of the SVC to the right atrium

What are the possible risks of CVP? 5

``` pneumothorax AV fistula air emboli arrhythmia thrombosis/infection ```

What are the normal CVP levels? _-_ mmHg

2-6

How can you evaluate the filling pressure in the left atrium?

PAC (pulmonary artery catheter)

Where would a PAC be inserted? where should it be placed?

neck veins | pulmonary artery

What else can be evaluated using PAC?

pulmonary pressure | cardiac production

What are the possible risks of PAC? 5

``` arrhythmia (VT...) AV block PE valvular damage bleeding ```

__ is a complete C/I for PAC

LBBB

What are the normal levels of PCWP (Pulmonary wedge pressure) measured by PAC?

8-12 mmHg

ASA classification= __

standards for basic anesthetic monitoring

ASA standard I= anesthetist should be present during __ and follow the __ status based on dynamic changes of the patient.

anesthesia | hemodynamic

ASA standard II- continues monitoring of 4 during all stages of the anesthesia.

ventilation oxygenic circulation temperature

ASA standard II requires __ analyzer, pulse __, monitoring __, signs monitoring every _ minutes, __ measurement and adapting the room accordingly.

``` oxygen oximeter EtCO2 5 temperature ```

Name 5 reasons for instability during surgery:

``` MI PE pneumothorax anaphylaxis malignant hyperthermia ```

How would you manage a patient suffering from MI during surgery?

hemodynamic stable and no perfusion disorder- continue instable patient- cease surgery and evaluate

_% of patients going through hip surgery may suffer from __.

2 | PE

What are the clinical presentation of a perioperative PE? 3

tachycardia hypotension hemodynamic collapse

How do you diagnose perioperative PE?

TEE

How do you treat perioperative unstable PE?

cease the treatment and give cardiac support/thrombolytic/embolectomy

Pneumothorax is a common __ complication. Clinical signs include: 4

laparoscopy desaturation hypercarbia hypotension

How do you manage an unstable perioperative pneumothorax?

cease surgery -> stop inflating the abdomen ->pulmonary tube

What are the common causes for perioperative anaphylaxis? 4

latex relaxants (rocuronium, vecuronium, succinylcholine) Abx blood products

How do you manage an unstable perioperative anaphylaxis? 4

adrenaline H2 blockers Hydrocortisone fluids

Malignant hyperthermia is usually with a __ predisposition (__/__)

genetic Duchenne muscular dystrophy other myopathies

What is the clinical presentation of malignant hyperthermia? 8

``` increase sympathetic activity rapid hyperthermia rigidity metabolic/respiratory acidosis hypotension arrhythmia seizures CPK/myoglobinuria ```

What is the treatment for malignant hyperthermia? 6

``` stop all suspected anesthetic dantrolene cooling sodium bicarbonate (for acidosis) treating hyperkalemia treat arrhythmia ```

When performing preoperative evaluation ask if in the past there was a delayed waking up after anesthesia as a marker for __ deficiency.

pseudocholine esterase

If a patients has a pseudocholine esterase deficiency- avoid ___.

succinylcholine

Mallampati score relates to the distance between the __ and __.

tongue | pharynx

Mallampati class 1: ___

soft palate + uvula + anterior/posterior pillars

Mallampati class 2: ___

soft palate +uvula

Mallampati class 3: ___

soft palate + uvula base

Mallampati class 4: ___

soft palate is invisible

How wide should the mouth opening and thyromental distance be?

6-8 cm (3-4 fingers)

What are the 4 criteria in Mallampati classification?

class mouth opening thyromental distance neck extension

``` What are the death percentage for each ASA score? 1- 2- 3- 4- 5- 6- ```

``` 1- 0.06-0.08% 2- 0.27%-0.4% 3- 1.8-4.3% 4- 7.8-23% 5- 9.4-51% 6- 100% ```

ASA 1= ___ patient

healthy

ASA 2= mild __ disease w/o __ limitation (eg. __).

systemic functioning balanced HTN/DM

ASA 3= ___ systemic disease with functioning ___ (eg.__).

severe limitation COPD/MI history

ASA 4= Severe __ disease with a __ life threat (eg. __).

systemic constant unstable angina/HF

ASA 5= Expected __ if surgery will not be performed in the next __ hours (e.g. __).

death 24 aortic aneurysm/brain bleeding/MOF

ASA 6= ___ before __.

brain death | organ saving

When assessing a patient cardiovascular status pre-op check if there was a previous __. If the answer is yes- consult a cardiologist, if not- continue.

ACS

MACE (major adverse cardiac events) >__% requires further investigation.

METs (metabolic equivalents) > 10- ___

no further investigations, continue to surgery

METs (metabolic equivalents) 4-10- ___

no further investigations, continue to surgery

METs (metabolic equivalents) <4- ___

further investigation is needed (exertional test/heart mapping)- if not in order -> PCI

If PCI was performed, surgery is done __ days after.

If PCI + BMS was performed, surgery is done __ days after.

If DES was performed, surgery is done __ months after.

6-12

Patients with ICD require an ___ to be present in the OR.

external defibrillator

What does the pulmonary pre-op check involve? 5

``` history physical CXr ABG respiratory function ```

__, __, and __ are not significant respiratory risk factors.

smoking obesity mild asthma

Patients with OSA are in increased risk for prolonged __.

dyspnea

In the case of active COPD/asthma consider to __ the surgery until respiratory __.

postpone | stabilization

Patients going through dialysis should be operated _-_ hours after their last treatment.

18-48

Diabetic patients should __ there pump insulin treatment, keeping them in the __ values.

continue | basal

At the morning of the surgery, DM patients should use a __ dose of __-__ range insulin. Stop other related drugs (__)

decreased medium-long metformin

Pre-op fasting involves __ and __ for _ hours before. _ hours before the surgery, patients should avoid __ completely. Breast milk-__ hours cow mike- __ hours formula- __hours

``` solids clear fluids (water) 2 drinking 2 4 6 ```

Anticoagulation should be __ and bridged with __.

withheld | clexane

COPD patients should be treated with ___ before surgery.

bronchodilators

What is recommended for patients with risk for aspiration before starting the surgery? 2

pramin | PPI (a night before surgery)

Anti anxiety, usually __ can be used. Avoid in __, __ and __.

benzodiazepine | pulmonary disease/OSA/elders

What are the 3 anesthesia techniques?

local regional general

What are the indications for RSI (rapid sequence intubation)? 3

``` full stomach (emergency unfasted surgery) Increased abdominal content (pregnancy/abdominal mass/ascites) delayed gastric emptying (Bowel obstruction/opioid use/DM/pregnancy) ```

When performing RSI: 1) prepare the tools 2) preoxygenate (__) 3) give both __ and __ simultaneously 4) perform __ maneuver 5) __ 6) __

``` 100% oxygen for 3 minutes hypotonic (propofol) + muscle relaxant (rocuronium) Sellick intubate nasogastric tube ```

Local anesthesia mechanism is based on __ channel blockage in the neuro fibers

In local anesthesia, the lower the pKa, the __ the effect is, the more hydrophobic the __ potent, the better it can bind to protein the __ the effect lasts for.

faster more longer

What are the two groups of local anesthesia? 2

``` aminoamide (lidocaine) amino ester (chloroprocaine) ```

What are the neurotoxic signs of local anesthesia? 6

``` mouth tingling tinnitus visual impairment disorientation slurred speech seizures (treat with diazepam/thiopental if it doesn't pass) ```

What other clinical signs can be seen in local anesthesia toxicity? 2

arrhythmia (QRS prolongation) | metallic taste

How can you prevent local anesthesia toxicity? 2

pull before push | add epinephrine

The further away the regional anesthesia is from a __ blood vessel, the __ the absorption and __ effect.

large slower longer

What late complication can be caused by regional anesthesia? 5

``` headache back pain urinary retention neurological complications SSI/meningitis ```

What are the C/I for regional anesthesia? 5

local infection at the site coagulation disorder/active anticoagulant sepsis/bacteremia hypovolemic shock advanced neurological disease/elevated ICP

What are the indications for spinal anesthesia? 4

urologic surgery abdominal surgery anus surgery lower limb surgery

Spinal anesthesia effect is __, more __, and leads to less __ pain than epidural anesthesia.

faster efficient back

Spinal anesthesia block both __ and __ sensation under the level of the block.

motor | sensor

What are the advantages of spinal anesthesia? 3

preventing airway/general anesthesia complications the patients is awake (good for TURP surgery) less delirium in elders

What are the disadvantages of spinal anesthesia? 7

post-dural headache (more in young, women, large needle) hypotension/bradycardia neuropathy back pain urine retention epidural hematoma respiratory depression/arrhythmia if spreads cephalic

What are the indication for epidural anesthesia?

abdominal surgery chest surgery lower limb surgery

In epidural anesthesia the needle is inserted into the __ space between the ligamentum __ and the __ matter.

epidural flavum dura

What are the advantages of epidural anesthesia? 4

better respiratory functions better pain control less pneumonia (same mortality) less ileus

What are the disadvantages of epidural anesthesia? 3

``` epidural/spinal hematoma epidural abscess (requires MRI) ```

What are the risk factors for epidural hematoma? 2

coagulation disorder/anticoagulation | prophylactic clexane post surgery

What are the clinical presentations of spinal hematoma?

back pain motor/sensory disorder of the lower limbs urinating/defecation disorder

Stop clexane __ hours before epidural catheter insertion. Avoid clexane _ hours after the insertion.

24 | 6

Stop clexane __ hours after epidural catheter clexane removal. Resume clexane __ after removal.

12 | 2

In the first 24 hours post-op the patient should regain time/place orientation. In case of delirium/tough awakening - treat with __.

Haldol

What are the criteria for extubating? 3

``` independent breathing (4-6 cc/kg TV or 30>RR>7 ) awake/responsive/protective reflexes/TOF ratio>0.9 no hypothermia/acidosis/electrolyte disorder ```

In case of post anesthetic laryngospasm treat with: positive pressure oxygen (__) -> ___ ___

CPAP succinylcholine ventilation

In case of post anesthetic vocal cord edema treat with: __-> inhalator and IV ___ + inhalator __

oxygen steroids epinephrine

PONV=__

post operative nausea & vomiting

PONV is caused by central damage to the __. Treatment includes __ (careful from long QT) and if administrated with __ + __ can cause bradyarrhythmia.

brainstem Droperidol Ondansetron Metoclopramide

Using __ for maintenance reduces the frequency of PONV.

propofol

30 minutes post op the desired body temp should be > __.

hypothermia increases the risk for:

MI in CAD patients (due to shivers->oxygen demand) drug metabolism coagulation disorders (death triad) SSI

Chronic pain lasts > __ beyond the expected healing time from surgery.

a month

Chronic pain is describes as: 3

burning stinging shock like

What are the risk factors for chronic pain? 5

* surgery type (neck/mastectomy/thoracotomy/hernia/amputation) * SSI * nerve pain during the surgery * DM * tumor involvement (nerve entrapment)