Anesthesia Curriculum

Question 1

Normal lung volumes (TLC, TV, VC, FRC)

Answer 1

Question 2

Normal lung volumes (RV, ERV, IRV, FVC)

Answer 2

Question 3

Effects of general anesthesia on the FRC

Answer 3

Question 4

Hgb dissociation curve

Answer 4

Question 5

Five etiologies of hypoxemia

Answer 5

Question 6

Mallampati

Answer 6

Question 7

Hyomental distance

Answer 7

• >3 cm is favorable for intubation

Question 8

Thyromental distance

Answer 8

• > 6cm is favorable for intubation

Question 9

Normal head extension

Answer 9

At least 35 degrees

Question 10

Basics of the airway exam: The four M’s

Answer 10

• Mallampati
• Measurements (Hyomental, thyromental)
• Movement (Head extension)
• Malformation (anything obstructive or loose, BMI)

Question 11

Airway emergency

Answer 11

Cannot intubate AND cannot ventilate

In other words, if you cannot intubate but you can bag and mask ventilate, it’s not an airway emergency.

Question 12

Rapid sequence intubation

Answer 12

Induce the patient with an anesthetic and give a muscle relaxant (usually Succinylcholine or Rocuronium) that works fast in order to intubate the patient as soon as possible without mask ventilation

A rapid sequence induction is a good choice for patients that are at increased risk for aspiration (trauma, GERD, pregnant, diabetic gastroparesis, full stomach)

Question 13

When a patient with 100% O2 sat is cyanotic, you always need to consider two things

Answer 13

1. Carbon monoxide
2. Methemoglobinemia

Question 14

Cormack and Lehane classification

Answer 14

• Grade 1 view: all of vocal cords/laryngeal aperature
• Grade II view: arytenoids only
• Grade III view: epiglottis only
• Grade IV view: palate only

Question 15

Levels of anesthesia

Answer 15

Question 16

Minimal Sedation (Anxiolysis)

Answer 16

a drug-induced state during which patients respond normally to verbal commands.

Although cognitive function and physical coordination may be impaired,

airway reflexes, and ventilatory and cardiovascular functions are unaffected.

Question 17

Monitored Anesthesia Care (“MAC”)

Answer 17

• Does not describe the continuum of depth of sedation
• Rather it describes “a specific anesthesia service performed by a qualified anesthesia provider, for a diagnostic or therapeutic procedure.”
• Indication: “the need for deeper levels of analgesia and sedation than can be provided by moderate sedation (including potential conversion to a general or regional anesthetic.”

Question 18

Moderate Sedation/Analgesia (“Conscious Sedation”)

Answer 18

drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation.

No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.

Question 19

Deep Sedation/Analgesia

Answer 19

a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation.

The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.

Question 20

General Anesthesia

Answer 20

a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation.

The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired.

Question 21

The laryngeal mask airway partially protects the larynx from ___, but not ___.

Answer 21

The laryngeal mask airway partially protects the larynx from pharyngeal secretions, but not gastric regurgitation.

Question 22

The earliest evidence of bronchial intubation often is an increase in ___.

Answer 22

The earliest evidence of bronchial intubation often is an increase in peak inspiratory pressure.

Question 23

Ensuring that when you intubate someone you haven’t gone into the esophagus

Answer 23

• direct visualization during intubation
• presence of bilateral breath sounds
• absence of gastric gurgling while ventilating
• analysis of exhaled gas for the presence of CO2
• chest radiography, airway ultrasonography, or use of fiberoptic bronchoscopy

Question 24

Closing capacity

Answer 24

• The maximal lung volume at which airway closure can be detected in the dependent parts of the lungs
• Closing capacity is normally well below FRC, but it rises steadily with age. This increase is probably responsible for the normal age-related decline in arterial O2 tension.

Question 25

FEF25-75 utility in obstruction

Answer 25

Whereas both forced expiratory volume in the first second of exhalation (**FEV1**) and forced vital capacity (**FVC**) are **effort dependent**, forced midexpiratory flow (**FEF25–75%**) is more **effort independent** and may be a **more reliable measure of obstruction.**

Question 26

Effects of the mechanics of anesthesia on the FRC

Answer 26

* Changes in lung mechanics due to general anesthesia occur shortly after induction. * The **supine position** **reduces the FRC by 0.8 to 1.0 L,** * and induction o**f general anesthesia further reduces the FRC by 0.4 to 0.5 L.** * **​Net: reduction by 1.2 to 1.5 L** * FRC reduction is a consequence of alveolar collapse and compression atelectasis due to loss of inspiratory muscle tone, change in chest wall rigidity, and upward shift of the diaphragm.

Question 27

Anesthesia and shunt

Answer 27

General anesthesia commonly **increases venous admixture to 5% to 10%,** probably as a result of **atelectasis and airway collapse in dependent areas of the lung.**

Question 28

Direct effects of alveolar CO2 on O2

Answer 28

**Large increases in PaCO2** (\>75 mm Hg) readily **produce hypoxia** (PaO2 \<60 mm Hg) **at room air,** **_but_****, not at high FiO2.**

Question 29

Central chemoreceptors

Answer 29

Central chemoreceptors are thought to lie on the **anterolateral surface of the medulla** and respond primarily to changes in **cerebrospinal fluid [H+].** This mechanism is effective in regulating **PaCO2,** because the blood–brain barrier is permeable to dissolved CO2 but not to bicarbonate ions.

Question 30

Chemoreceptor summary image

Answer 30

Question 31

Effects of anesthesia on CO2 ventilation curve and apneic threshold

Answer 31

With increasing depth of anesthesia, the **slope of the PaCO2/min ventilation curve decreases,** and the **apneic threshold increases.** The mechanism is probably dual: **central depression of the chemoreceptor** and **depression of external intercostal muscle activity.**

Question 32

PaCO2 ventilation curve

Answer 32

Question 33

PaO2 ventilation curve

Answer 33

Question 34

Class and Grade of airway

Answer 34

Question 35

Stable angina as a surgical risk factor

Answer 35

Really not a very significant risk factor. **Stable angina is *_not_* an indication to reschedule a procedure** and consult cardiology. Unstable angina, on the other hand, would be an indication for this.

Question 36

Pros and Cons of patient controlled analgesia

Answer 36

* **Pros** * Peaks and troughs are less severe * Analgesic level better matched to analgesic need * Patient has autonomy * **Cons** * May lead to pruritis, ileus, sedation, respiratory depression * may not cover all major surgical pain, but may provide additive effect

Question 37

Precedex

Answer 37

* **Centrally acting alpha 2 agonist _analgesic_** * Much higher affinity for alpha 2 receptors than clonidine, the other centrally acting alpha 2 agonist * Clonidine also has weak analgesic properties

Question 38

Para-aminophenol

Answer 38

* **COX-3 inhibitor analgesic** * Same mechanism as **acetominophen** * Controversy exists over the exact mechanism, as for tylenol

Question 39

Where different analgesics act

Answer 39

Question 40

Trauma patients are generally not going to be \_\_\_

Answer 40

Trauma patients are generally not going to be **NPO**

Question 41

Good anesthetic choices for asthmatic patients

Answer 41

* **Induction agents** * Propofol * Ketamine * **Analgesics** * Fentanyl * **Gas anesthetics** * Isoflurane * Sevoflurane * **Muscle relaxants** * Succinylcholine * Rocuronium

Question 42

What anesthetics do you want to *avoid* in asthmatic patients?

Answer 42

* **Morphine** (causes histamine release, bronchoconstriction) * **Atracurium** (causes histamine release, bronchoconstriction) * **Desflurane** (causes airway irritation, especially in smokers)

Question 43

Normal ETCO2 curve

Answer 43

Question 44

ETCO2 curve in obstruction

Answer 44

Question 45

Management of asthma attack during anesthesia

Answer 45

1. **Increase bronchodilatory gas anesthetic** (if using) 2. Add **albuterol** inhaler via endotracheal tube 3. If no improvement, administer **lidocaine** 4. If no improvement, administer **epinephrine**

Question 46

Things that may mimic bronchoconstriction during anesthesia

Answer 46

* **Inadequate anesthetic depth** * Mechanical obstruction (patient **biting on tube, tube kinks**) * **Secretions** (may be seen in tube, can suction to remove) * **Pneumothorax** from barotrauma (unlikely, but do not miss)

Question 47

Assist-controlled ventilation vs SIMV

Answer 47

* **Assist-controlled:** * If ventilator senses a patient-initiated breath, it delivers a full tidal volume. Thus, patient controls the ventilatory rate, with a built-in minimum baseline rate * **May worsen air-trapping/breath-stacking/dynamic hyperinflation** in those with obstruction, but allows for **minimal work of breathing**. PEEP may increase intrathoracic pressure and **decrease venous return.** * **SIMV:** * Combination of spontaneous, unsupported breathing with a built-in minimum baseline rate. Leaves a "window" of breathing opportunity for the patient. Does not deliver a set tidal volume upon patient breaths. * **Improves V/Q matching,** but may **produce an excessive work of breathing** and more likely to be **dyssynchronous** than AC

Question 48

Pressure support ventilation

Answer 48

* Similar to pressure-controlled assist-controlled, but different mechanism terminates inspiration: * In AC, inspiration is determined by time. In PS, **inspiration is determined by decreasing gas flow (~25%)** * Patient triggers each breath, but provides decreased work of breathing. WOB can be gradually increased by playing with settings. * No true back-up rate * **Ideal mode for ventilator weaning**

Question 49

Indications for spontaneous breathing trial

Answer 49

* Improvement in factors that led to ventilator dependence in the first place * Assessment of oxygenation: * PaO2/FiO2 ≥ 150 mmHg * PEEP ≤ 8 cm H2O * FiO2 ≤ 0.5 * pH ≥ 7.25 * Hemodynamic stability (low dose vasopressors ok) * Spontaneous respirations

Question 50

Criteria for a successful SBT

Answer 50

* **30-120 minute duration** * **None of the following met/exceeded:** * RR \> 35 breaths/minute * HR \> 140 or a sustained ↑ of 20% from baseline * SBP \> 180 mmHg or DBP \> 90 mmHg * ↑ anxiety * ↑ diaphoresis

Question 51

WHEANS NOT mnemonic for difficult to wean patients

Answer 51

* **W**heezing * **H**eart disease * **E**lectrolyte problem * **A**nxiety, **a**spiration, **a**lkalosis * **N**euromuscular weakness * **S**epsis * **N**utritional deficit * **O**besity * **T**hyroid disease

Question 52

CPAP vs BIPAP

Answer 52

* **CPAP** * continuous stream of pressure throughout respiratory cycle, stents the airway open, portable * **BIPAP** * increased pressure on inspiration, less on expiration, better tolerated than CPAP but requires constant supervision of pressures

Question 53

Why is aortic stenosis such a big deal in anesthesia?

Answer 53

Three reasons: 1. The coronaries are on the other side of the aortic valve, so their **arterial pressure is already reduced** by the addition of a large resistor 2. Anesthetics will lower the arterial blood pressure, resulting in an even **lower arterial pressure** 3. PEEP from ventilation **increases venous pressure** * The net effect of all of the above is **significantly reduced coronary perfusion pressure**

Question 54

Effects of benzodiazepines on hemodynamics

Answer 54

Really no significant effects. They are decent at facilitating induction in patients with cardiovascular issues

Question 55

Effects of opioids on hemodynamics

Answer 55

* Decrease SNS activity, decreasing SVR and HR

Question 56

Effects of paralytics on hemodynamics

Answer 56

* **Pancuronium:** increases HR, BP and CO due to a possible vagoly:c and sympathomime:c effect * **Atracurium:** causes histamine release, resulting in vasodilation and drop in SVR and BP * **Vecuronium:** May cause tachycardia * **Rocuronium and succinylcholine** have negligible effects.

Question 57

Effects of induction agents on hemodynamics

Answer 57

* Generally all decrease SVR and preload, with the exception of Etomidate

Question 58

Effects of inhaled anesthetic gases on hemodynamics

Answer 58

* Most **decrease SVR** and **increase HR** * The exception is **halothane**, which **decreases CO** via direct myocardial effects

Question 59

We don't cancel surgery for stable angina, but we do for symptomatic \_\_\_

Answer 59

We don't cancel surgery for stable angina, but we do for **symptomatic aortic stenosis**

Question 60

Management of aortic stenosis intraoperatively (if you have to do surgery on someone with significant aortic stenosis)

Answer 60

Question 61

Effects of left ventricular hypertrophy on the atrial kick

Answer 61

**Makes the atrial kick more imporant:** It's **relative contribution to preload** increases from **10% to 30-40%.** So, atrial fibrillation in someone with LVH *really* drops the blood pressure, since it is both uncoordinated and you lose the preload contribution.

Question 62

LV and RV perfusion

Answer 62

The LV is only performed during diastole, while the RV is performed continuously (due to relative pressures)

Question 63

Components of an ABP tracing

Answer 63

Question 64

\_\_\_\_ have the added benefit of protec:ng the myocardium from ischemia and reperfusion injury and decreasing MI size.

Answer 64

**Volatile anesthetics** have the added benefit of protec:ng the myocardium from ischemia and reperfusion injury and decreasing MI size.

Question 65

Clonidine for opioid withdrawal

Answer 65

Question 66

Methadone for OUD

Answer 66

Question 67

Buprenorphine for OUD

Answer 67

Question 68

Long term antagonism with naloxone . . .

Answer 68

. . . **increases sensitivity to opioids** Since it is blocking endogenous receptors -- it makes neurons upregulate them. So, you really want to **avoid opioids in patients taking chronic naloxone.**

Question 69

In someone with a poor gag reflex who has poor ventilation, why can't you bag and mask to ventilate?

Answer 69

To prevent aspiration

Question 70

Severe sinus bradycardia and AV block after insufflation for laporoscopy

Answer 70

Sometimes observed due to activation of the peritoneal stretch receptors Anesthesia must monitor the patient very carefully for this vagal response during insufflation

Question 71

Respiratory Alkalosis of Pain

Answer 71

Untreated pain *alone* can produce a substantial respiratory alkalosis If you see a respiratory alkalosis and hyperventilation without a good etiology (such as in the context of a reasonable pO2 greater than 80)