Noninvasive Monitoring

Question 1

How do we place a modified V5 Lead?

Answer 1

Modified V5 lead (MCL): used to detect anterior and lateral wall ischemia if only using 3 lead electrodes

• Place right arm lead in right midclavicular line
• Left arm lead in 5th intercostal space next to left nipple
• Left leg lead on left iliac crest
• Monitor in Lead 1

Question 2

other sites of pulse oximetry

Answer 2

penis.

Question 4

What can measuring Nitrogen tell us?

Answer 4

Highest amount of Nitrogen is in room air

if you have a high Nitrogen amount in a patient it is indicative of

Pulmonary Embolus

Question 5

Best site to monitor for extubation?

Answer 5

ADDUCTOR POLLICIS

Question 6

What does a Curare cleft signify?

Answer 6

The patient is starting to breathe again.

Question 7

When do you have fade?

When don’t you have fade?

Answer 7

You have fade on non-depolarizing

You DO NOT HAVE FADE IN SUX

Question 8

What two leads do you monitor in the OR?

Answer 8

LEADS II AND V5

Question 9

What can cause this?

Answer 9

Rebreathing CO2

• Faulty expiratory valve - DR. MASSIES CHOICE
• Inadequate inspiratory flow
• Insufficient expiratory time
• Malfunction of CO2 absorber system

Question 10

Best site to monitor for intubation?

Answer 10

FACIAL

Question 11

Tetanus: stimulus delivered at _____ Hz

for ___ seconds

Answer 11

Tetanus: stimulus delivered at 50-100 Hz

for 5 seconds

we want to see sustained 5 seconds

Question 12

What muscle is resistant to sux? what muscles are sensitive to it?

Answer 12

Diaphragm - resistant

Laryngeal muscles -sensitive

Question 13

What effect would Methemoglobin have on pulse oximetry?

Answer 13

the same absorption at both the red and infrared wavelengths, creating a 1:1 ratio

• The resulting 1:1 ratio corresponds to a saturation reading of 85% (algorithmically)
• So methemoglobinemia c_auses a falsely low SpO2 when saturation is actually greater than 85% and a falsely high SpO2 when saturation is actually lower than 85%_

Question 14

The only quantitative monitoring technique we use (neuromuscular)

can much residual NMB can this detect?

Answer 14

Acceleromyography (AMG): monitor measures muscle acceleration via piezoelectric sensor; piezoelectric crystal generates voltage when put into motion due to muscle contraction

• can detect 97% of residual NMB

Question 15

What can cause this waveform?

Answer 15

• Baseline elevated
• Abnormal descending limb of capnogram
• Allows patient to rebreathe exhaled gas

Question 16

the gold standard of endotracheal tube placement and verification

Answer 16

CAPNOGRAPHY

- CONTINUOUS MONITORING OF ALVEOLAR VENTILATION –

Question 17

Patterns of electrical stimulation

A single twitch delivers how many Hz? how long will it last?

how many seconds?

how many pulses?

Answer 17

• Single twitch: single pulse delivered every second to every 10 seconds at 0.1- 1.0 Hz, lasting 0.1-0.2 seconds

Question 18

What does the line from C to D represent on the capnography waveform?

Answer 18

- end airways that are releasing the last bits of carbon dioxide.

Question 19

What happens in Phase I?

Answer 19

Phase 1: inspiration from points E to A, during which CO2 level remains zero

Question 20

With nondepolarizing muscle relaxants:

• Loss of 4th twitch represents ___% block
• Loss of 3rd twitch = ___% block
• Loss of 2nd twitch = ___% block
• Loss of 1st twitch = ___% block

Answer 20

Loss of fourth twitch = 75 % block

Loss of 3rd twitch = 80% block

Loss of 2nd twitch = 90% block

Loss of 1st twitch = 100% block

Question 21

Shows the best approximation of alveolar CO2 (end of expiration beginning of inspiration)

Answer 21

POINT D

Question 22

What is the wavelength of Oxyhemoglobin (HbO2)

Answer 22

940-990 nm

wavelength

Question 23

What light does Deoxyhemoglobin absorb?

what is the wavelength?

Answer 23

Deoxyhemoglobin absorbs more red light at 660 nm

wavelength

Question 24

What is the formula for functional saturation?

Answer 24

Question 25

What does **Lead II recognize and detect?**

Answer 25

**Lead II** **recognizes P waves easily and detects** **dysrhythmias**

Question 26

What is this waveform?

Answer 26

**SUDDEN DROP IN EtCO2** --you are in the goose-- ***--gradual drop is usually obstruction--***

Question 27

limits the degree of desaturation that can be tolerated

Answer 27

**Oxyhemoglobin dissociation curve:** limits the degree of desaturation that can be tolerated ## Footnote * Between **90-100%** saturation, PaO2 will be **\>60** torr * **Below 90%** saturation, curve becomes steeper and **small drops in saturation** correspond to **large drops in PaO2** – Narrow range of safety

Question 28

What is a **restrictive disease?**

Answer 28

Neuromuscular diseases [inspiration] longer [I] time Pulmonary Fibrosis **Obesity** **Pregnancy**

Question 29

**Mandatory AANA/ASA standard monitor** to aid in detecting hypoxemia

Answer 29

**Pulse Oximetry**

Question 30

**Possible causes of Irregular plateau or baseline** - displacement of the tracheal tube into the upper airway or larynx or lower pharynx with intermittent ventilation of the stomach and lungs or from pressure on the chest which causes small volumes of gas to move in and out of the lungs.

Answer 30

**Inadequate Seal Around ET tube** * leaky or deflated endotracheal or tracheostomy cuff * Artificial airway is too small for the patient

Question 31

How many **twitches** does TOF show, **how many second interval** at how much **Hz?**

Answer 31

* Train of four (TOF): **four twitch** stimuli in **2 seconds at 0.5 second intervals at 2 Hz** – --\>\>\>\> Twitches progressively fade when relaxation occurs and vice versa

Question 32

How many ETCO2 waveforms do you need to see to **verify that you are in the trachea?**

Answer 32

**3** good **ETCO2 waveform**

Question 33

A point in time [DURING CASE] when we are looking at our anesthetic EtCO2 when we realize that we have to get it **higher.**

Answer 33

**EMERGENCE** -end of the case- (45-50 --\> resp. drive kick in)

Question 34

What is this? Where is the first place you'll check or what will you think?

Answer 34

Classic progressive obstruction on patients with **COPD, ASTHMA, EMPHYSEMA** 1. Think about patient history (reactive airway?) always go back to differential diagnosis. Reactive airway disease --\> listen to the patient to see if the patient is wheezing [flip off the vent] 2. Patient might be biting? (IA, Propofol, Muscle relaxant --\> if the case is longer]

Question 35

What is the **basis** of pulse **oximetry?**

Answer 35

The **change in light absorption during arterial pulsation** is the basis of pulse oximetry

Question 36

What does **lead V5 view**? what does it **detect?**

Answer 36

## Footnote **Lead V5** views the **anterior** and lateral portions of the **left ventricle** and **detects myocardial ischemia**

Question 37

is this a normal waveform?

Answer 37

**Yes.** A classic pic of some room air being entrained because you have a leak in that tubing.

Question 38

What else could cause **a decrease in the EtCO2** reading **from normal to a sudden low value?**

Answer 38

***_PE_***

Question 39

What is the **formula for MAP?** what does it signify?

Answer 39

Question 40

What **effect would Carboxyhemoglobin (COHb)** have? What is the **patient population** that may have this?

Answer 40

COHb has an **absorption spectrum similar to oxyhemoglobin (940 nm)** so **most pulse oximeters will _overread the SpO2_** in **_smoke inhalation patients --\> falsely high readings_** –Toxicity: cherry-redappearance(latesign!)

Question 41

What is an **_indicator of a good EtCO2 reading?_**

Answer 41

**GOOD _ALVEOLAR PLATEAU_**

Question 42

This is used to **determine the adequacy of neuromuscular blockade intraoperatively** and adequacy of **relaxant reversal postoperatively**

Answer 42

**Peripheral Nerve Stimulation (PNS)** **Neuromuscular monitoring**

Question 43

What type of patient would you change your high CO₂ alarm?

Answer 43

**COPD --\> baseline is higher CO2** **Chronic Sleep Apnea** - patient safety, normalization of deviants -

Question 44

ON PHASE II : What does points **B to C represent?** **capnography**

Answer 44

**B to C** That's when we're beginning to see the patients **_beginning to empty from all their connecting airways, going through their bronchi._** **_And it's getting all the way down to the Alveolar_**

Question 45

On BIS numerical display when do we know general anethesia?

Answer 45

**General anesthesia is within 40 -60**

Question 46

What is the characteristic of a **normal capnogram**

Answer 46

* Rapid increase from B to C * Nearly horizontal plateau between C and D * Rapid decrease from D to E to zero * Zerobaseline(E to A and Ato B)

Question 47

Full onset **NMB is faster** among these muscles?

Answer 47

Full onset of NMB is faster in the: **M**asseter muscle **A**dductor pollicis **M**uscles of the foot Centrally located muscles (diaphragm, facial, rectus abdominis, laryngeal adductors, and orbicularis oculi)

Question 48

Does pulse oximetry need recalibration?

Answer 48

LED’s provide _monochromatic light;_ this means they emit a **constant wavelength throughout life**, so once calibrated, they ***_never need recalibration_***

Question 49

What is the correct size of cuff/bladder size? why is this important? What will be the blood pressure reading if the cuff is too small for an obese patient?

Answer 49

◦ As the site becomes **more periphera**l, the **SBP increases** and **DBP decreases** * Cuff/bladder size influences the pressure measured ◦ Cuff should be **40-50% of the circumference of the limb** with a **length that is 80-100%** of the circumference will provide accurate readings ◦ **Too small cuff** will reflect falsely **higher pressure** and **too large cuff falsely lower pressure** * –Obese patients: if the cuff is too small, the pressures will be falsely elevated