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Clinical Reference Deck > PoA1 > Flashcards

PoA1 Flashcards

1
Q

Where does hypobaric solutions gravitate toward?

A

C3 (phrenic nerve) and L3, the high points when a patient is supine

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2
Q

What arteries supply the cord? Where do they originate

A

Anterior Spinal Artery (from vertebral artery 75%), 2 Posterior Spinal Arteries (25%), and segmental spinal arteries

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3
Q

Dura Mater origin and endpoint

A

Foramen magnum and to the end of Dural Sac S2

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4
Q

CSF Factors

A

150ml total
decreased CSF amount means increased LA spread and to use a lower amount
Common causes are low weight increased abdominal pressure

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5
Q

Thumb Dermatome

A

C6

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6
Q

Spinal Considerations: Lidocaine

A

It’s pretty short acting, used for outpatient

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7
Q

Which spinal is goated for duration

A

Bupivacaine (0.75% in 0.5% dextrose)

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8
Q

Morphine Neuraxial Adjunct key points

A

Water soluble hydrophilic and will lead to delayed respiratory depression from slow spread in CSF

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9
Q

Opioid Neuraxial side effect and prevention

A

Pruritus use <300 mcg morphine, 50-75mcg it’s absent, give 4mg zofran or Nubain prophylactically

Respiratory Depression lipophilics will occur sooner (Fent and Sufent) later with hydrophilic agents (morphine)
They DO NOT prolong block, only enhance density

And urinary retention

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10
Q

Alpha 2 Agonist Neuraxial Effect

A

Intensifies and Prolongs the block and analgesia (Dex, Clonidine)

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11
Q

Differential Blockade

A

nerve fibers withing a nerve means we see a progression of block onset

B sympathetic fibers, then C & A delta fibers (i.e. slow pain,touch and temp are blocked second),

B-Sympathetic, then C and A delta (pain, temp, touch), followed by A Gamma (Motor tone/NOT SENSORY) then A Beta (touch, pressure) then A Alpha (motor and proprioception) Recovery is inverse so B Sympathetic fibers are blocked longest

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12
Q

LA Drug/Controlable Factors affecting (Spinal) block height

A

Dose (increase dose, increase duration), baracity, site of injection, patient position

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13
Q

LA Patient/Non Controlable Factors affecting Spinal block height

A

CSF volume, age, baracity, increased intra-abdominal pressure (fluffy or pregnant)
Greater Cephalad spread with greater age(greater neural nerve sensitivity), baracity(?) and less CSF

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13
Q

Bezold-Jarisch Reflex

A

Protects LV when active, leads to bradycardia and hypotension
BJR is treated by Zofran as it’s mediated by 5HT3 receptors in vagus nerve

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14
Q

Respiratory Response to Neuraxial

A

If high thoracic (T4) block, loss of Abdominal Muscle contribution in forced expiration-limits ability for active exhalation

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15
Q

Thermo response to Neuraxial

A

shivering-Meperidine and Precedex and clonidine will treat it

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16
Q

LAST/Failed Block get out of jail free card

A

1.5ml/kg 20% intralipid bolus for LAST, followed by 0.25ml/kg/min gtt

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17
Q

Most probable LA anaphylaxis cause

A

PABA in Ester LA

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18
Q

Block height for C-Section

A

T4

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19
Q

Block for Knee Tourniquet

A

T10

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20
Q

Needle Insertion Layer Path

A

Skin, subQ fat, supraspinous, interspinous, ligamentum flavum, dura mater, subdural space, arachnoid mater, subarachnoid space

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21
Q

What spinal approach for metal rods or scoliosis

A

Paramedian-10-15 angle difference from midline

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22
Q

“Total or High” Spinal

A

Unexpected cephalic spread of LA to high cervical/cranial nerves

caused by excessive dosing (and why you should check dermatomes frequently) or Rapid LA injection

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23
Q

Postdural Punction Headache

A

Failure of dura puncture site to heal
Headache is when pt is upright

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24
Q

PDPH Treatment

A

2-3 days after Headache when upright

Supine bedrest, NSAIDs, Fent, Caffeine/Methylxanthine (vasoconstriction), blood patch ~48 hours post onset

More likely with an Epidural as the gauge required is larger

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25
Q

Cauda Equina Syndrome

A

L2-S5 coccygeal nerves are affected by LA procedure

**2/2 High dose 5% lido, Microcatheter use-causes lido to pool in cauda equina, and Small Whiticare 25/26 needle **

**IF DISC COMPRESSION, LAMINECTOMY IS NEEDED IN UNDER 6 HOURS

symptoms range from back pain, saddle anesthesia, to ED, GU/GI dysfunction

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26
Q

Auditory/Facial/Ocular Effects

A

Horner’s syndrome- ptosis, miosis, anhydrosis

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27
Q

Epidural Pregger Concern

A

Baston’s plexus is engorged in the Lateral epidural space

Dont inject into them, blood upon CSE entry means youre too lateral

**Be a Chad and inject inert fluid to open the epidural space prior to catheter insertion

Blood in the catheter is also seen with multiple attempts, stiffer catheters or trauma to the epidural vein

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28
Q

Why is 3% Chloroprocaine the fastest onset with a pK of 9?

A

High 3% concentration leads to quicker onset, whats used in surgical anesthesia

very short-duration is 45min and is an ester

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29
Q

What is the order of LA route onset greatest to least?

A

IV, tracheal, intercostal, caudal, paracervical, epidural, brachial, sciatic, subQ

I Told Immediately Chelsea Please Eat Big Scallop Subs

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30
Q

Epidural Dosing per segment

A

1-2mL per segment
give 5mls at a time to avoid High Spinal

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31
Q

Neuraxial Alkanlinization

A

Speeds up onset, bicarb (1mEq/10ml) decreases [H+]/Increases nonionized drug

increases diffusion of drug AND speed of block onset

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32
Q

Epidural Procedure Unique steps

A

Loss of Resistance with the air or saline
Test dose with 3mL of 1.5% Lido + (1:200,000) Epi to see if IT or IV

uses 45mg Lido and 15mcg Epi

If HR jumps 20% or patient has metalic taste in mouth O O F
If dense motor block within 5 minutes occurs-you did a spinal essentially whomp whomp

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33
Q

Positive Test Dose Signs

A

Tinnitus, circumoral numbness, metallic taste

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33
Q
A
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34
Q

Why are esters metabolized quickly

A

Plasma Cholinesterases are how they are metabolized

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35
Q
A
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36
Q

Patients allergic to Tetracaine, Benzocaine, and cocaine have cross reactivity to?

A

PABA, and other Esters

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37
Q

ANAA monitoring frequency standards

A

BP, HR, and RR are q5 min
pulse ox is continous/mandatory, most do q3 min

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37
Q

What is the SpO2 if PaO2 is 40mmHg

A

75%
at 60 mmHg it’s 90
at 27 mmHg its 50

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38
Q

How is SaO2 estimated in pulse oximetry

A

Pulsatility of Arterial Blood

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38
Q

Carboxyhemoglobin Pulse Ox Concern? What is the % COHb in smokers?

A

Falsely elevates SpO2
typically over 6%- they desat quickly and youll need to adjust accordingly

Every 1% COHb increases, SpO2 increases 1%

due to COHb absorbing light in the 660nm range as O2Hb does

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39
Q

Pulse Ox Artifact Causes

A

IV dyes (methelyne blue will cause it to drop), Venous pulsatility (clots/transpo of great vessels)

ambient light, low perfusion, nail polish, and other Hb forms will mess it up

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40
Q

Korotkoff Sounds

A

Phase I: the most turbulent/audible (SBP)
Phase II: softer and longer sounds
Phase III: crisper and louder sounds
Phase IV: softer and muffled sounds
Phase V: sounds disappear (DBP)

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41
Q

Artline Waveform Periphery effect

A

Steeper upstroke, higher systolic peak, later dicrotic notch, lower End-Diastolic Pressure

Distal pulse amplification is from impedance

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42
Q

Square wave test

A

no more than two oscililations after fast flush and should get smaller

to look for good resolution- System dynamic response

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43
Q

Overdampening Waveform

A

absent dicrotic notch, lower sBP, narrowed PP with accurate MAP

Less detail

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44
Q

Pressure Waveform Analysis

A

identifies residual preload reserve and fluid status

looks at cyclic artieral BP change from respiratory cycle with PPVenting and Lung voume change

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45
Q

Positive Pressure Ventilation Effects on Pressure

A

Early Inspiratory phase- greater intrathoracic pressure, increased total lung volume - leads to less LV afterload and increased LV preload causing SV, CO, MAP to increase

Decreased venous return, increased PVR- leads to increased RV afterload causing decreased RV SV

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46
Q

Stroke Volume Variation

A

Normal is 10-13%
Computer calculates the stroke volume variation based on patient factors
if greater than 10-13% GIVE FLUID-youll see SVV of 12%

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47
Q

Pulse Pressure Variation

A

Max and min PP over the entire respiratory cycle

Normal is LESS than 13-17%

On the exam, if a patient is 13-17% GIVE THEM FLUID, YOULL SEE 14% PPV ON EXAM, GIVE VOLUME

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48
Q

Side-stream Gas Mixture Analysis

A

Most common, Lag time causes longer rise time

affected by tube diameter, length, sampling rate-bigger diameter, faster interpretation

Gas must be brought to analyzer, most common

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49
Q

Infrared Analysis/Absorption

A

O2 doesnt absorb IR radation (no dipole)

*measures CO2, N2O, H2O, and volatiles based on the asymmetry of molecules absorbing light at different lengths

measures energy absorbed of a IR band as it passes through a gas sample

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50
Q

What facial Nerve reflects laryngeal muscle block?

A

Corrugator Supercilii is goated-reflects laryngeal adductor and abdominal muscles better than the adductor pollicis

Ulnar Nerve is gold standard

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51
Q

Deep Non-depolarizing blockade

A

Absent TOF, post tetanic stim present
Reversed with 4mg/kg Sugammadex

Intense block- no response, 3-6 minutes after intubation dose of ND NMBD, reversal impossible unless 16 mg/kg sugamma

moderate- gradual return of 4 responses of TOF stimulation, neostimine reversal is good and sugammadex is 2mg/kg

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52
Q

Depolarizing Blockade Phase II

A

Presence of post-tetanic facilitation

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53
Q

How many channels does BIS use

A

4, 2 per hemisphere

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54
Q

What nerve picks up heat/warmth

A

Unmyelinated C

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55
Q

Hypothermia Complications

A

Coagulopathy-reversible platlet aggregation

Decreased O2 delivered to tissues
wound healing will take longer

Decreased Drug metabolism-NMB can be prolonged

Gotta be hot to clot

*increases transfusion need by 22%, blood loss by 16%

post thermal discomfort is a thing

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55
Q

What is the order of heat transfer greatest to least

A

Radiation (40%), Convection (30%), Evaporation (10%), Conduction (ask a magic 8 Ball)

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56
Q

Hypocarbia concerns

A

decreases CBF (cerebral vasoconstriction), blunts respiratory drive, decreases PVR, K goes extra to intracellular

ETCO2 of 28 mmHg, below is risky dingo

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57
Q

Bohr Equation

A

measures deadspace to tidal volume

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58
Q

Increased ETCO2 causes

A

is measured at the end of phase 3, largest just before inspriation

Caused by:
increased metabolism(Fever/MH/sepsis/seizures)
Bicarb
Decreased alveolar ventilation-hypoventilation/NM dz/High spinal

Equipment issue-rebreathing, CO2 absorber spent, leak in circuit, or faulty inspiratory/expiratory valve

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59
Q

Decreased ETCO2

A

Hypothermia
Cardiac Arrest
Hypotension
Hemorrhage
PE
HYPERventilation or Pain

Equipment wise- vent disconnect, goose egg intubation, complete airway obstruction(laryngospasm), poor sampling-the breathing rate cant be too fast for the line to grab a sample, ETT cuff leak-room air will dilute the expired sample

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60
Q

ETCO2 Phase 1

A

Respiratory baseline at 0, exhalation of anatomic deadspace/apparatus

1/3 of tidal volume is exhaled
No CO2 should be present unless rebreathing

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61
Q

ETCO2 Phase II Alpha Angle

A

110ish degrees- widened with expiratory airflow obstruction (COPD looks sharkfin, Bronchospasm, kinked ETT)
Causes slanted Phase 2, separates phase 2 and 3

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62
Q

Faulty Inspiratory Valve Effects

A

Widened Beta Angle, decreased slope of inspiratory downstroke (phase 0)
Can cause Rebreathing when not going back to 0 baseline

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63
Q

Cardiac Oscillations

A

More common in Peds, heart proximity to trachea causes this during inspiratory phase

rapid heartrate causes timing of various lung fields to be different

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64
Q

Re-breathing and Soda Lime exhaustion effect

A

CO2 rebreathing/Inspiration and baseline increases
phase 0 doesnt change
This and faulty valve will be on the exam

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65
Q

Curare Cleft

A

NMB is wearing off
Patient is spontaneously breathing during mechanical ventilation

reparalyze or flip off the vent if its the end of the case

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66
Q

Esophageal Intubation capnography

A

Wounded Pride Intensifies
spontaneous waveform then goes away, but if a tubes in it should be regular

if wave form has right ETCO2 peaks and regular rate then falls off, tube fell out or got kinked

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67
Q

What monitoring is continous in OR

A

BP and RR

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68
Q

What is my SpO2 if PaO2 is 40mmHg

A

75%

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69
Q

What causes slanted phase 2 in capnography

A

Faulty equipment, rebreathing

Phase 2 is the expiratory upstroke, CO2 Rich alveolar gas and is steep

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70
Q

What is the sensory portion of Oculocardiac Reflex?

A

CN V (Trigeminal Nerve)

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71
Q

Common cause of high spinal

A

Too high of a dose
rapid administration
incorrect positioning
misplaced epidural catheter

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72
Q

What is the mechanism of action of LAs

A

Na channel blockade, specifically from inside

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73
Q

What layer of the spinal column is responsible for the “Pop” during spinal/epidural

A

Penetration of the Dura Mater, entering the sub dura layer

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74
Q

Epidural Space Rostral, Caudal, Anterior, Posterior and Lateral borders

A

Rostral/Caudal: Foramen magnum to near S5/Sacrococcygeal ligament
Lateral: Vertbral Pedicles
Anterior: Posterior Longitudinal Ligament
Posterior: Ligamentum Flavum and Vertebral Lamina

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75
Q

Epidural Space Contents

A

Nerves, Fatty tissue, Lymphatics, Blood Vessels
Fatty tissue can absorb and decrease bupivcaine availabilty compared to Fent/Lido/Morphine

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76
Q

Plica Mediana Dorsalis

A

Lateral connective tissue band in the Epidural Space thought to cause epidural catheter placement issues and unilateral blocks

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77
Q

How many Cervical, Thoracic, Lumbar, Sacral, and Coccal nerves are there

A

Cervical 8
Thoracic 12
Lumbar 5
Sacral 5
Coccal 1

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78
Q

Where are Sensory information carried and Motor information carried?

A

Anterior Nerve Roots: Motor and Autonomic information from cord to body

Posterior Nerve Roots: Sensory information from the body to the cord

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79
Q

Umbilicus Dermatome Level

A

T10 Sensory Level

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80
Q

Are there spinal nerves innervating the face for sensory fields?

A

Nope, dat der CN5/Trigeminal nerve with the following branches:
V1-Opthalmic Nerve
V2-Maxillary Nerve
V3-Mandibular Nerve

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81
Q

Spinal/SAB/Intrathecal Block site of action

A

Subarachnoid space of the cord, specifically the myelinated preganglionic fibers of the spinal nerve roots

Also inhibits neural transmission in the superficial layers of the cord

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82
Q

Epidural site of action

A

In the epidural space outside the dura mater diffuses through the dural cuff to reach nerve roots to work

can leak thorugh the intervertebral foramen to the paravertebral space

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83
Q

Factors NOT affecting Spinal/SAB spread

A

Barbotage
Speed of injection
Bevel orientation
Vasoconstriction (e.g. Epi or Phenylephrine)addition
Gender
ALL DO NOT AFFECT SPREAD

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84
Q

EPIDURAL Factors affecting spread and block height

A

Controlable with significant effect:
LA volume
Level of injection
LA Dose
Controllable with less effect:
Local anesthetic concentration
Patient Position (has a significant effect but whatever)
Plica maybehaps

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85
Q

Epidural NON CONTROLABLE factors affecting spread

A

Greater affect: Pregnancy
Older age
Meh effect: Height(Taller may need 2 ml per segement, shorter lesser per)

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86
Q

Epidural factors that DO NOT affect spread

A

Additives (though they do intensify or prolong block)
direction of needle bevel
injection speed

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87
Q

Differential Blockade Zones

A

Sensory level is 2 levels higher than motor
Sympathetic level is 2-6 levels

So a T8 block has T10 motor blocked below and T2-T6 Sympathetic block-will need Phenylephrine/Ephedrine as HR and BP will drop

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88
Q

Bromage Scale

A

PACU Motor Blockade monitoring scale 0-3

0-gucci, born to run

1-slight block cant raise extended leg

2-moderate cant raise leg or move knee, CAN move feet

3-complete motor block cant move legs, knee, or feet

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89
Q

CV Systemic effects of Neuraxials

A

Preload is decreased from sympathetomy and venous pooling

Afterload decreased from partial arterial dilation-SVR decreases 15% in healthy people and 25% in elderly/trash EF patients

Cardiac Output is reduced from SV decreasing from the SVR/Venous Return effects
Intially CO may rise from the vessel dilation then proceeds to fall off a cliff

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90
Q

Reverse Bainbridge Reflex

A

Bradycardia triggered by reduced stretching of RA

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91
Q

Sudden Cardiac Arrest Cause and Incidence

A

Young adults with high parasympathetic unopposed from our acctions, occurs 20-60 minutes after
7:10,000 spinals
1:10,000 epidurals

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92
Q

Which drugs are indicated for hypotension with bradycardia secondary to SAB/Epidural? Hypotension solo?

A

Ephedrine dose, for bradycardia alone a dose phenylephrine/Neo
Wait for your HR to change before cycling the cuff, otherwise it’ll be another cattywampus read

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93
Q

Prevention of Spinal induced Hypotension

A

Vasopressors like Phenylephrine
5-HT3 antagonist Zofran to counter BJR

Fluids we move away from preloading and Co-load with 15mL/kg 700-1Lish. Please dont tank someone with trash EFs by fluid overload. Or kidney injury with colloids and making the blood too viscous

Positioning slight pelvic tilting/Head up to prevent Hyperbaric solutions to tank your pressures further

Atropine for bradycardia alone, however tachycardia in someone with CAD is a bad time

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94
Q

Pulmonary Effects of Neuraxial

A

Minimal Impact, even with T4, only ERV is decreased and by extension Vital Capacity

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95
Q

Pickwickian Syndrome

A

BMI 40-50 when laid flat they panic as ERV and VC are low from baseline
Reassure them and raise the HOB and get Semi Fowler Action going
putting on a nasal cannula will be a dice throw, some will be bothered more by it

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96
Q

Diaphragm Innervation

A

C3, C4, C5

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97
Q

GI Sympathetic innervation

A

T5-L2
Sympathetic afferent-sends visceral pain
Sympathetic efferent-inhibits peristalsis, gastric secretion also causes sphincter contraction, and vasoconstriction

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98
Q

GI Parasympathetic

A

Afferent-sends saitey, distention, nasuea
Efferent-tonic contraction, sphincter relaxation, peristalsis, and secretion

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99
Q

GI Neuraxial Effect

A

Increases Parasympathetic and reduces Sympathetic tone
Increases Peristalsis, 20% incidence of N/V
Reduces post op ileus in abdominal surgery

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100
Q

GU Neuraxial Effects

A

RBF is stable if MAP is maintained
If you block above T10 urinary sphincter tone is relaxed
addition of Neuraxial Opioids decreases detrusor contraction and Increases bladder Capacitance
PACU will probably need a reminder to bladder scan

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101
Q

Neuraxial Metabolic Effect

A

Surgical stimulus elevates catecholeamines, cortisol, and RAAS
can partially suppress or totally block (in lower extremity cases) neuroendocrine response if it’s placed before surgical stimulus

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102
Q

What determines the hydrophilicity of LA?

A

Tertiary Amine, it is what accepts protons

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103
Q

LA intermediate chain big deal

A

determines drug class and allergic potential cough cough Esters and PABA cough cough

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104
Q

Amide Metabolism

A

P450

105
Q

Local Anesthetic Duration

A

How protein bound to A1-Glycoprotein

106
Q

Factors Affecting Vascular Uptake and Plasma Concentration of LAs

A

Site of injection
Tissue blood flow
Physiochem properties
Metabolism
Vasoconstrictor addition

107
Q

Which baracity of LA is good-er for hips

A

Isobaric, based on positioning and duration it stays put

108
Q

Where do Hyperbaric solutions like to settle when patient is supine?

A

T6 and S2

109
Q

Subarachnoid/Spinal dosing generally?
What would a T10 dose of 0.75% Bupivacaine be?

A

generally: are fixed, onset is 5 minutes, lastes 130-220 minutes
15 mg, of .75% means 7.5mg per ml and so 2 mLs

110
Q

Epidural Dosing Concentrations

A

Very low concentrations-Ropivicaine is 0.1-0.75%, Bupivacaine is 0.0625-0.5% as is Levobupivicaine

111
Q

Epidural Top Up dose

A

50-70% to be given when sensory block segment drops 2 dermatomes

112
Q

Epidural: for a thoracic versus lumbar

A

Lumbar space is dummy thicc so give 2 mls per segment, Thoracic is thinner so 1 will suffice as it’ll spread more

113
Q
A
114
Q

Epidural: Would a “walking epidural” be a lower or higher concentration? Why does it matter

A

lower concentration to achieve sensory block but spare motor

Concentration of LA in epidurals determines density/strength of block

115
Q

Neuraxial Opioid Target

A

Substantia Gelatinosa of the dorsal horn (lamina 2)

Helps curb neurotransmission by decreasing cAMP, Ca2++ and increasing K++

116
Q

Lipophilic Opioid adjuncts

A

Fent/Sufent have a shorter duration in CSF, and less spread

Onset is quicker, but duration is shorter so respiratory depression occurs earlier

117
Q

Intrathecal Dose of Demerol/Meperidine? Epidural dose?

A

Intrathecal: 10 mg

Epidural: 25-50mg
Infusion rate is 10-60mg/hr

118
Q

Intrathecal dose of Morphine? Epidural?

A

Intrathecal: 0.25-0.30 mg

Epidural: 2-5mg

infusion rate is 0.1-1 mg/hr

119
Q

Neuraxial Alpha 2 Adjuncts and dose

A

Clonidine 15-45 mcg
Precedex 3 mcg
Intensifies and prolongs block, can cause bradycardia and hypotension
off label use

120
Q

Neuraxial Vasoconstrictor adjuct dose and mechanism?

A

Epi 0.2-0.3 mg “epi wash”
Phenylephrine 2-5 mg
Profoundly increases tetracaine duration

121
Q

Anticoagulation/Antiplatelet Neuraxial risk

A

Epidural hematoma, cord compression essentially
They’ll get lower extremeity weakness numbness, low back pain, and GI/GU dysfunction
whomp whomp if you DONT surgically decompress via laminectomy in 8 hours

122
Q

Aspirin and Montelukast mechanisms

A

Aspirin stops COX-1
Risky if your stopping it in secondary use patient-means theyve already had a stroke

Montelukast stops 5-LPO and helps asthmatics by curbing LTC4

123
Q

Neuraxial guidelines for aspirin

A

High risk- oof and hold it 4-6 days regardless of 81 or 325mg
Central doesn’t require holding it

124
Q

NSAID Neuraxial precautions

A

For high risk procedures e.g. open aorta peripherial vascular hold for 5 1/2 lives

Central does not require any holding

125
Q

Glycoprotein 2B/3A antagonist rec’s for peripheral anesthesia

A

Hold Tirofiban and Eptifibatide 4-8 hours
Abciximab 24-48

126
Q

Thienopyridine Derivative neuraxial guidlines

A

Clopidogrel 5-7 days
Prasugrel 7-10
Ticlopidine 10 days

127
Q

Unfractionated heparin rec’s

A

Recall it puts factor 2/antithrombin on turbo, and inhibits factors 2 and 10

lower doses <5K units 4-6 hours
Higher doeses ~20k units 12 hours
therapeutic >20K or pregnant patient hold 24 hours
If on it for over 4 days get a platelet count first prior to central neuraxial, hopefully it’s over 100k

128
Q

LMWH (lovenox) heparin

A

Prior to block should be 12 hours since last dose for prophylactic

delay for 24 hours if it’s a bigboi therapeutic dose

Antifactor 10a in old farts/renal patients is a good idea

129
Q

Vitamin K Neuraxial Recs

A

It impaires factors 2, 7, 9, 10

Warfarin Hold for 5 days, make sure INR is gucci (<1.5)

130
Q

Would you give regional/neuraxials after T-PA

A

Of course not. Absolute contraindication

Recall: thrombolytics activate plasminogen which bonk fibrin and break clots down

131
Q

DOAC Rec’s for Neuraxial

A

Eliquis, Bevyxxa (seriously?) Lixiana, Xarleto, Pradaxa all inhibit factor 10a

D/C 72 hours before, look at anti-factor 10a if pressed

132
Q

Herbal Rec’s for Neuraxial

A

behave similar to plasminogen, fine if patient isnt on any other blood thinners

133
Q

Sphenopalatine Ganglion Block (SPG)

A

Soak or “pledge” a swab with LA (1-2% Lido or 0.5% Bupivacaine)
basically jam it in nostril toward the pack of the head, angled inline with the tragus line

Works on the V2 divison of CN5

134
Q

Parethesia

A

Fancy word for pain
After a SAB/Epidural, patient has deficit near area of placement

associated with poor placement during needle advancement in Spinal/Epidural
Less likely with Epidural
More likely with CSE and not being midline

135
Q

“Failed Spinal”

A

No anesthesia- You didnt stick the landing, if spinal is not active in the patient after 15-20 minutes try again

Patchy block- swallow pride and consider TIVA/GETA, repeat incurs neurotoxicity risk

Unilateral Block- adjust position, if that doesnt work TIVA/GETA is the play

136
Q

GOAT antiseptic approach for neuraxial

A

Neuraxial step 1: open kit
Neuraxial step 2: throw iodine in trash
CHG + Alcohol pad
Dont be lazy, grab it ahead of time and wear gown, gloves, hat, the whole kit and kaboodle

137
Q

Transient Neurologic Symptoms

A

Improper positioning stretching nerves, causing temporary myofacial strain/spasms

typical s/s are radicular pain in the back and buttocks, onset within 6-36 hours of surgery. Lasts 1-7 days

Caused (ish) by 5% lido, awkward positions like lithotomy (hip/knee flexion), and outpatient knee

throw NSAIDS at them like candy and trigger point injections

138
Q

Retained Catheter Fragments

A

After epidural, remove introducer and catheter together to avoid shearing

139
Q

Unilateral Epidural Block

A

Catheter was shot too far, exiting the epidural space or is smooshing a nerve

pull cathere back 1-2 cm but ensure 3-5 cm still is in the epidural space

Also reposition patient to side that still isnt blocked i.e. left side down if their left side still is feeling it

140
Q

LAST

A

Common cause is inadvertent injection
usually seen with seizure, if bupivacaine is the causitive agent cardiac arrest is seen first

expect a spectrum of analgesia then circumoral numbness/tinnitus/hypotension and myocardial depression, then seizures, and finally coma/respiratory arrest with mounting plasma concentration

141
Q

LAST systemic Risk/concerns

A

CNS: risk is higher with hypercarbia-higher cerebral perfusion higher LA drug deliver
Hyperkalemia-neurons are more excitable and

metabolic acidosis-lowers seizure threshold and increases brain drug retention via ion trapping

142
Q

What decreases LAST risk

A

Hypocarbia
Hypokalemia
CNS Depressants

143
Q

LAST Treatment

A

Manage airway-100% O2
Treat seizures- benzos please dont crump cardiovascular system and avoid propofol
Modified ACLS- give epi in low dose 1mcg/kg and amio for ventricular issues

Lipid emulsion- 20% lipid 100ml bolus, then 250ml over 15-20 minutes. Repeat if still unstable

144
Q

Arachnoiditis is associated with

A

LA with preservatives, and wipe off surgical prep off (especially if it’s betadine)
Fever is the first sign in 1-3 days
dont be a gilgamesh, make sure LA is farm fresh

145
Q

Why should you have a GETA set up for neuraxial

A

Failed Spinal
High Spinal
LAST
Anaphylaxis
CV collapse
Case exceeds LA duration

Wrong dose, wrong location, or position are the causes

146
Q
A
146
Q

Cutting Needles

A

That there be your Quincke and Pitkin and will likely be associated with PDPH

Pencil point needles drag less shit and the “Pop” is more pronouced

147
Q

Spinal Steps

A

Timeout
Monitors (BP/SpO2)
Positioning (Mad Cat)
ID/Mark SAB interspace
Sterile prep with sponges
Drape
Draw meds with SAB filter
Wipe excess betadine off
localize with 1%
Instert spinal needle
once crossing dura youll hear pop
Withdraw stylet and watch for CSF
Rotate needle 360 (checks if youre in the right spot if CSF flow is weak-advance need a smidge more)
Aspirate CSF with syringe of SAB LA to check for swirl (if it’s hyperbaric)
Inject SAB LA
Lay them flat quickly
BP/HR revaluation
Dermatome assessment
5 minutes to prevent high spinal

148
Q

Common Spinal Problems

A

No flow when you spin the needle 360-advance
No swirl
paresthesia-reposition them
Blood instead of CSF-check it wasnt from the prior insertions
No block-check dates in your kit, it might’ve expired
Parital block

149
Q

Epidural Needles

A

Tuohy-has the most curvature aobut 30 degrees and blunt tip protects SAB space

Crawford is used when catheter placement is difficult or steep angle like thoracic- no curvature

Weiss-has wings, 15 degree curve

150
Q

Epidural Catheter factoids
If your Tuohy has 4 cm outside the patient how much is in the epidural space?

A

Multi-orifice catheter has better distripution
optimal epidural space of the needle is 3-5 cm

the tuohy is the introducer sheath and is 9cm up to the hub, so 9-4cm means 5cm is in the patients epidural space

For documentation of placement you put “10cm” at the skin-5 is in the go zone, and 4 is outside plus the cm window thus 10

151
Q

Lumbar Tattoo and Epidural Concern

A

Perform after 5 months of the tattoo
Try to avoid henna or if your spooked it’s fine to bail
chart the concerns and discussion with patients

152
Q

During epidural how do you find your epidural space

A

with the tuohy needle with the tuohy needle

153
Q

If lumbar epidural started at L4-L5 how many mLs are needed for T10?

A

start at the level and count backwards but not counting L4. So 6 levels, 1-2 mLs per level so 6-12 mLs

and if you rolled with 6, top up dose would be 3 cm (50%)

again test with cold temps like a spoon and aspirate just in case of catheter migration to IV or SAB spaces

154
Q

Lidocaine top up dose time

A

60 min

155
Q

2-Chloroprocaine top up dose time

A

45 min

156
Q

Mepivacaine top up dose time

A

60 minutes

157
Q

Bupivacaine and Ropivacaine

A

120 minutes

158
Q

Epidural Common Mishaps

A

CSF “Wet Tap”-overpenetration into dural space and CSF comes out.
Paresthesia-plica might bonk your advance and
Cant advance or thread catheter- again plica
Aspirate blood- wrong spot, always aspirate slow and give increments

Positive test dose, but dont be a goober and give it during a contraction-that’ll be a false positive

159
Q

CSE

A

Combined spinal epidural
Spinal is done first, but use Tuohy as introducer
So find epidural space, then find dura which shouldnt be too much further for the Pop drop your LA for spinal

Leave the Tuohy in to thread the epidural catheter-retract tuohy a smidge then thread it

160
Q

In preop if you auscultate and hear a random rhythm and EKG shows Afib and the patient doesnt know do you proceed?

A

Nope, Cancelectomy unless you want to throw clots

161
Q

Beer lambert and Pulse ox light absorption

A

Greater solute concentration (more stuff in blood) or greater light path length (vasodilation/more tissue) means more of the stuff in the vein/container is absorbing more light

162
Q

Pulse ox VS Co-oximetry

A

Pulse ox looks at 2 wave lengths,
co-oximetry looks at 4, may be needed with elevated altitudes or COHb

163
Q

deO2Hb absorbs red light or IR more?

A

More red light (660 nm)

164
Q

O2Hb absorbs more IR or Red light?

A

IR light (940nm)

165
Q

Pulse Ox advantages

A

in healthy peeps withing ABG ~2% when over 70%

not affected by volatiles
noninvasion
continous
convenient and can pick up cardiac output

166
Q

Pulse Ox disadvantages

A

Poor function in clamped states
Delayed hypoxic detection
Dysrhythmias throw it off-aflutter etc
different Hbs can throw it off
dyes will block the read, optical interference

167
Q

Pulse ox tips

A

Detection of desaturation is slower peripherally e.g. an endoscope will show it faster

dont put it on index finger, patient could bonk themselves

with epidural blocks toes would be primo

Tongue, cheek, forehead are less affected by vasoconstriction/reflects desatutation

168
Q

MAP formula

A

MAP = DP+1/3(SP-DP)

169
Q

BP Auscultation issue

A

Shock/vasoconstriction states
Severe edema/Atherosclerotic vascular changes
Wrong cuff
Cuff bladder should be 40% of circumference of arm
Bladder should be 80% of length of upper arm, centered over artery
Extremes in habitus

170
Q

Auto Cuff concerns

A

uses oscillometry-MAP maybe falsely low during hypertension, falsely high during hypotension

in ill patients/elders SBP will differ the most than a-line
Healthy folks it’ll be accurate
Atherosclerosis, edema, obesity and chronic HTN will narrow PP
check different arms if not arm surgery
Cuff too large- low BP
Cuff too small- high BP

171
Q

Allens’ Test

A

80% accurate (for 5 second return)

if color return to hand takes over 10 seconds-you have reduced collateral flow

172
Q

Seldinger’s technique

A

Stab with needle
pass guidewire
remove needle
thread catheter

173
Q

A-line tranfixion techinique

A

Same positioning/prep as Seldinger
stab through front and back wall intentionally
needle removed
catheter is withdrawn slowly until pulsatile flow appears and then is advanced
supposedly not associated with higher complication rates

174
Q

A-line optimization

A

auto NS flus 1-3ml/hr to prevent thrombus
zero to atmospheric air
level to aortic root
Maximize waveform- limit stopcocks, tubing length, and non-distensible tubing (stiff)

175
Q

What is happening at a-line waveform phase 2, 3, 4, 5, and 6?

A

Phase 1 is AFTER the R wave on EKG and dicrotic notch signifies

176
Q

A-line waveform closer to heart vs periphery

A

further away, arterial upstroke is steeper, systolic peak higher, dicrotic notch is later and end-diastolic pressure lower

impedance and harmonic resonance along the vascular tree is why

177
Q

A-line waveform formation

A

Fundamental wave+ Harmonic wave
6-10 harmonics are required via fourier analysis

178
Q

A-line Underdamping

A

Waveform looks very artifact heavy
multiple notches

179
Q

A-line overdampening

A

Looks like a small hill
systolic decreased
absent dicrotic notch
False narrowed PP
accurate MAP

180
Q

Aging changes with Pressures

A

less distensible/Atherosclerosis contribute to widened pulse pressure

waveform looks jagged/sharper

181
Q

A-line complications

A

distal ischemia/pseudo aneurysm
hemorrage
arterial embolus
local infection
peripheral neuropathy from trauma/etc

182
Q

Postive Pressure Ventilation effects on pressure during exhalation

A

opposite of inhalation
decreased RV stroke volume leads to reduced LV filling, reduced LV SV, and reduced systemic arterial pressure

183
Q

Systolic Pressure Variation

A

in mechanically vented patients normal is 7-10 mmHg

basically the swing up of 2-4 mmHg and down 5-6 mmHg, more likely in sickies

Increased SPV = give fluid/early sign of hypovolemia- means preload reserve is bupkis
so called “pressure swing”

184
Q

What to PPV, SPV and SVV rely on for calculation

A

Mechancial ventilation of 8-10ml/kg
PEEP of over 5 mmHg
Regular rate and rhythm
normal intra-abdominal pressure
CLOSED CHEST

185
Q

Frank Starling

A

Preload response curve

186
Q

Expired gas sampling sites

A

Y-piece of mask circuit arm
jammed on a facemask
taped to a patient
it varies

187
Q

Total Response time for gas analysis

A

Transit time- lag for gas to reach analyzer
Rise time- time taken by the analyzer to react to the change in gas concentration
side-stream responses- dependent on sampl

188
Q

Mainstream and Side-stream gas sample shared issue

A

watervapor will condense in tubing/sampling site and will throw it off

same with vomiting/secretions

189
Q

Mainstream sampling cons

A

More points for disconnects
blood/secretions will disable it

Rise time is faster, no time delay as it’s in the circuit

190
Q

Side-stream sampling issues

A

Takes Longer
Kink in tubing will throw it off
water vapor
failure of sampling pump-wont have a read at all
leaks in line - common at the screw in attachment points and with reuse
Slow response time

191
Q

Dalton’s Law

A

summative of the parital pressures
e.g. Room air PP is 160mmHg
160 mmHg/760mmHg) x 100% = 21 volumes %

192
Q

Mass Spec vs Raman Spec

A

Mass we use all the time, concentration of gas versus mass/charge ratio to tell you what percent the gas mixture is of sevo/N20 etc.
Can calculate 8 separate gasses

Raman-argon laser blasts the shit of a gas sample to form protons, photon scatter is measured in a spectrum to identify gas and its concentration
NOT USED

193
Q

IR analysis concept

A

gas has unique IR band absorption
IR light is beamed through a sample, then continues past in a narrow-band filter (simlar to a toy stereoscope) and the light detected = concentration

Less light detected = higher concentration

194
Q

Water vapor calculation in gas sampling

A

Side stream analyzers report ambient temperatures (ATPD) and DRY pressures

Analyzers really should sample at body temp and pressure saturated values (BTPS)
whatever just subtract 47mmHg from a sample to calculate partial pressure

E.g. O2 at 30% PP? = (760-47)(0.3)= 214 mmHg

195
Q

Fuel/Galvanic Cell battery

A

O2 wont be analyzed because its used to measure current as O2 diffuses across the battery membrane

current is proportional to partial pressure of O2 in fuel cell

Short life span, slow response time-monitor O2 in inspiratory limb

196
Q

Paramagnetic

A

detects sample line pressure changes from attraction of O2 and its mag field changes

signal change correlates with O2 concentration

used in most side-stream sampling
Rapid interpretation- breath by breath
*changes in ETCO2 can be faster than

197
Q

Oxygen monitoring

A

Most important

Calibrate for high and low concentrations

sample from Inspiratory limb, indicates if your air mixture is enough in your mix
**tells you when denitrogenation is complete and ETO2 is 90% and above

198
Q

Low O2 alarm causes

A

Pipeline crossover (OR hoses are swapped like N20 with O2)
Tanks on the back are filled wrong
Failure of the proportioning system e.g. N2O

199
Q

High O2

A

dont give 100% to premies and homies on bleomycin

200
Q

Airway pressure monitoring

A

look at the gauge/monitor, keeps you keyed in about ventilation, kinks, ETT occlusions or issues in the scavenging system

mechanical pressure gauges are always on and highly reliable-no recording

electronic gauges are integrated in the circuit
circuit disconnects will be the most common offender

201
Q

Pressure alarms

A

Mostly for circuit disconnect/leaks

doesnt pick up on partial leaks, low pressure limit should be just below normal peak airway pressure

70% of disconnects occur at Y piece

202
Q

Sub atmosphereic pressure alarm

A

measures/alerts circuit pressure for reverse flow of gas
negative pressures are super spooky- flash pulmonary edema, atelectasis can occur

can stem from suction scavenging malfuction
PATIENT BREATHING AGAINST BLOCKED CIRCUIT LIKE LARYNGOSPASM
whack fresh gas flow
suction to NGT/OGT in wrong spot
CO2 absorber is too moist

203
Q

High pressure alarms

A

activate if pressure exceeds a limit
useful in pediatrics
usually caused by eh compliance lungs, coughing/straining kinked ETT, endobronchial intubation

204
Q

What do continued pressure alarms mean for you

A

10 cm H20 over 15 seconds
Fresh gas continues to enter circuit but cant exit

APL valve is whack, scavenging system is occuluded, or you activated the O2 flush are usually why
PEEP malfunction also contributes

205
Q

Types of nerve monitoring

A

Electronic and magnetic
Magnetic sucks because its heavy, bulky, no TOF function and hard to illicit upramaximal effect (all or none stimulation pattern)
how many nerves activated determines muscle response

206
Q

What muscle is last to be knocked out and quickest to recover from paralytics

A

Diaphragm baby

207
Q

Single twitch

A

single twich 1 Hz (each second) to 0.1 (each 10 seconds)

need a reference before NMBD

208
Q

TOF

A

4 supramax stimuli every 0.5 seconds
TOFR is last response to 1st
Partial ND block- TOFR decreases/fades and is inverse to degree of block
e.g. immediately after NMBD expect 0 twitches, 20 minutes later the fade

209
Q

Partial Depolarizing block

A

No fade, ratio is 1:1
IF FADE IS PRESENT WITH DEPOLARIZING BLOCKADE YOU HAVE PHASE 2

210
Q

Double burst

A

2 short bursts of 50Hz
3.3 mode is 3 impulses in each of the 2 bursts
3.2 first burst hast 3, 2nd burst has 2

essentially compares the first twitch with the fade of the second twitch

211
Q

Tetanic stimulation

A

50 Hz for 5 seconds, zaps the shit out of the patient

Non-depolarizing agents- one strong sustained contraction with fade after stimulation

painful and again less clinical utility

212
Q

Tetanic stimulation with Depolarizing NMBD

A

Depolarizer agent- strong sustained contraction without fade
if fade is present in depolarizing block-Phase 2 has occured
think pseudocholinesterase patients or sux readmission

213
Q

Post-tetanic Stimulation

A

Composite stim- 50hz for 5 seconds, then after a 3 second pause 10-15 single zaps at 1 Hz.

depends on blockade
frequency/duration of tetanic stim
frequency of single twitch stimulation

for deep surgical blockade, done every 6 seconds

214
Q

Depolarizing Blockade

A

Phase 1- no fade or tetanic stimulation, post tetanic also absent
All 4 responses are reduced but equal and then disappear at the same time
normal plasma cholinesterase

Phase 2- fade present in TOF and tetanic stim- post tetanic stimulation faciculation present also
resembles non-depolarizing blockade
abnormal plasma cholinesterase activity

215
Q

Peripheral Nerve stimulation caveats

A

Keep them warm-cold nerves dont respond as well
attach old school probes before induction and turn on after unconsciousness
Moderate blockade is fine at 1-2 responses to TOF, tell surgeon womp womp

Reverse at 4/4 TOF otherwise delayed recovery and will have issues

Check for head lift 5 seconds, leg lift for 5 seconds, hand grip for 5 seconds, or max inspiratory pressures

216
Q

EEG stuff

A

looks at excitatory and inhibitory PS potentials
electrodes correlate with surface area over cortical regions **uses at least 16 channels

identifies: awake, zonked, seizure activity, stages of sleep, coma
hypoxemia or ischemia as well

Amplitude-size/voltage of signal
Frequency-number of hits/oscillations over 0-voltage line
Time-duration of sample signal

217
Q

EEG OR uses

A

used to ID cerebral cortex ischemia
correlates anesthetic CRMO2 reduction
can be used to correctly gauge hypnotic state and if anesthetics need to be dialed back
can predict outcome after brain insult

218
Q

EEG waves

A

Beta- over 13 Hz- awake and alert

219
Q

EEG Alpha wave

A

8-13 Hz- eyes closed
So 10Hz on the exam, put anesthesia/asleep
ideally where you want your patients-alpha land

220
Q

EEG Theta and Delta

A

Theta 4-7hz
Delta less than 4 hz
they be depressed

slower frequency and lower amplitude

221
Q

BIS/Processed EEG

A

Compresses 4 channels into one wave form, 2 channels per hemisphere
both hemispheres are necessary to check if both sides are good, or if one is rekt from carotid clamping

has artifact with the EEG signal so chart why if you ditched it

222
Q

BIS

A

0- flat line
100- awake
60-40 should be GA land, no response to verbal stimulus or likelihood recall
again not bulletproof compared to endtidal agent monitoring- if youre giving 2.2% sevo and they have 2.2% on Fe they zonked zonked

223
Q

Sensory-Evoked Responses

A

Most common evoked potentials used

CNS zaps intraop in spine/neuro cases to assess nerve anatomy integrity- looks at the cortical, subcortical, and periphery

described in latency-time to response after the zap
amplitude-size/voltage of recorded zap to baseline

224
Q

SSEPs

A

Monitor peripheral motor and sensory nerve stimulation and sensorimotor cortex response

Mostly will use short latency SSEPs as anesthesia will prevent the longer ones

Induction, neurological age, or different electrode locations can alter the SSEP waves

225
Q

BAEP

A

Brainstem Auditory Evoked Potentials
foam earplug inserts send a click in the ear to the auditory cortex, and the brainstem response is recorded

226
Q

VEP

A

Visual Evoked potential
weird light goggles send a flash stimulating retina and response is recorded

again SSEP will be the most common

227
Q

Motor-Evoked Potentials

A

Monitors signaling over the motor tracts, spinal columns, peripheral nerves, and innervated muscle for boo boos

Transcranial motor-evoke potentials are the most common MEP
looks at the stimuli along motor tract via transcranial zaps overlying the motor cortex

228
Q

Electromyography

A

monitors cranial and peripheral motor response to zaps to alert early detection of surgical damage and assess nerve function

looks at cranial or peripheral nerves at risk during surgery

229
Q

Temperature monitoring

A

Primary thermocontrol-hypothalamus
Unmyelinated C fibers - heat and warmth receptors
Alpha and delta fibers - cold receptors

Response is dictated by:
Threshold-is the temp low/high enough to get a response
Gain- how intense is the stimulus
Response-does the temp force sweating, vasodilation/constriction, or shivering

Anesthesia, age, menstral shit, drugs, ETOH, and circadian will alter it

230
Q

GA hypothermia

A

initally 0.5 to 1.5 C from anesthesia induced vasodilation, further heat loss from body heat reduction that occurs over 30min

**next slow linear reduction at 0.3 C per hour, GA reduces metabolic rate by 20-30% as heat loss exceeds production 1-2 hours after anesthesia

3rd is plateau steady state, heat loss and production are the same, vasoconstriction prevents core heat loss but periphery still has heat bleed

231
Q

Neuraxial Hypothermia

A

Patients wont complain of feeling cold-epidural will block the C fibers

Heat loss may not reach plateau phase as peripheral vasoconstriction threshold is altered/doesnt occur

Neuraxials decrease thresholds that trigger peripheral vasoconstriction and shivering-central thermoregulation is off

Autonomic thermoregulation defenses impaired so techincally sweating, vasodilation, shivering, and vasoconstriction are impaired

232
Q

Radiation

A

heat loss to environment- 40% of patient heat loss
Body surface area exposed to environment and babies have a high BSA/body mass ratio making them vulnerable

233
Q

Convection

A

Loss of heat to air immediately surrounding the body approximately 30%
clothes/draping decreases loss, increased in rooms with laminar flow

234
Q

Evaporation

A

latent heat of vaporization of water from open body cavities, resportory tracts-8-10%
sweating is the main pathway, in ex-laps saline soaked gauze averts it
excessive sweating under GA should set off your spidey senses-check a sugar probably hypoglycemic

235
Q

Conduction

A

heat loss from direct body tissue contact with cold fluids/materials, is negligible
e.g. contact between skin and OR table, IV compartment and cold iv infusion during MH event

236
Q

Hypothermia Benefits

A

Protects against cerebral ischemia
Reduces metabolism 8% per degree celsius
MH theorhetically will be harder to trigger
useful in NSGY with expected ischemia
Improves cardiac arrest recovery

237
Q

Peri-Op temp management

A

airway heating/humidification in circuit more seen in peds

warm IV fluids and blood-prevents cooling

Skin warming- keep room temp higher in liver xplants, trauma, peds
Insulation as well with blankets, slows loss by 30%

Hot water mattress-more effective and safe on top of patient

Forced air warming-more common and prevent loss from radiation, e.g. bair hugger using convection

238
Q

Temp monitoring sites

A

P.A. is the gold standard but eh were getting away from it- correlates with tympanic, distal esophageal, and nasopharyngeal temps

Tympanic temps-approximates hypothalamustemp, but can perf it

Nasopharyngl reflects brain temp but is prone to errors, nose bleeds

Esophagus-safe, accessible, accurate place in lower third/fourth of esophagus

239
Q

OR Temperature generally

A

70F or 21C for peds
65F or 18C

240
Q

Capnography big picture

A

Tells us about ventilation, metabolism, and CV
what goes in must come out
to a lesser extent can tell us pulm blood flow, aerobic metabolism, ETT/LMA placement, breathing circuit integrity and CO

If ETCO2 drops off randomly-check the circuit and swap it out and it should return
compressions are on point if ETCO2 returns

241
Q

Hypercarbia effects

A

Respiratory Acidosis
Increase in CBF-ICP risk in neuro patients-back off on opioids
Pulmonary Vascular Resistance
K shifts from intracellular to intravascular

242
Q

Bohr Equation

A

Calculates physiological dead space to tidal volume

243
Q

Dead space

A

Mouth to just before gas exchange regions of lungs
150ish ccs for this class

244
Q

Anatomic deadspace

A

conducting zones of airway-nose, trachea, bronchi

245
Q

Physiologic deadspace

A

airway deadspace+alveolar dead space

Alveolar dead space- physio deadspace not exchanging gas in the alveolar space

246
Q

Causes of Alveolar Deadspace (V/Q mismatch)

A

Hypovolemia
Pulm HTN
PE
Ventilation of nonvascular airspace
precapilary obstruction pulm vessels
Obstruction of pulmonary circulation from outside forces
Alveolar distention

247
Q

Capnometry

A

Measurement and quantification of inhaled or exhaled CO2 as measured by capnometer

248
Q

Capnography

A

method of CO2 measurement and graphic display of time, breath to breath
outside of CXR best way to confirm intubation
we want three accurate, strong wave forms

249
Q

Time capnography

A

Pressure vs Time plot-most common representation
CO2 concentrations are recorded as inspired or end tidal

Highspeed-shows detail of each breath shows nice detail of each one
Slowspeed-shows trend looks all squiggly
strips look opposite of what youd think

250
Q

ETCO2 measurement location

A

at the end of phase 3
usually just prior to inspiration, is the largest value but can vary manufacturer to manufacturer

will be asked “is it end of expiration” on exam-yes it is

251
Q

Arterial/ETCO2 difference

A

5 mmHg, so ETCO2 of 35 means arterial ETCO2 is 40mmHg

V/Q mismatch increases the difference of PaCO2 and PACO2-PE or Endobronchial intubation

COPD, bronchospasm, and neonate breathing can make it worse

Capnograph can have an issue and will tell you to recalibrate if slow response time to breathing pattern, or sample catheter has a leak

252
Q

Noninvasive McGuyver ETCO2 method

A

jam the sample line in a face mask and tape the side vents, or Nasal cannulas will have it in the cannula

253
Q

Clinical measurement of ETCO2

A

IR light absorption-greater CO2 in sample, less IR light reaches detector

Chemical indicators turn pH paper yellow if CO2 is present-sensitive to low CO2 but ETT needs second verification as it could be in the esophagus

254
Q

ETCO2 monitor requirements

A

CO2 Read must be withing 12% of actual value
manufactures has to disclose if ethanol, acetone, or halogenated requirements

Must have a high CO2 alarm for inhaled and exhaled CO2
Must have a low exhaled CO2 alarm

255
Q

Time Capnogram Interpretation

A

interpreting CO2 values, approximate blood CO2 levels, Pulmonary Blood Flow, and Alveolar Ventilation can be inferred by capnogram

DDx of loss of exhaled CO2- Goose egg intubation, accidental extubation, sample line disconnect, apnea, bronchospasm or cardiac arrest

Inspiratory - phase 0 the down slope
Expiratory- phase 1, 2, and 3

256
Q

ETCO2 Phase 3

A

plateau phase, representative of CO2 in alveolus, indicator of ventilation heterogeneity, slight increaseing slope-not all alveoli close at the same time otherwise it wouldnt have a slope

257
Q

ETCO2 Phase 4

A

phase4isphase0phase4isphase0

inspiration of fresh gas is washing out remaining CO2, downstroke returns to baseline

258
Q

Occasional Phase 4

A

sharp upstroke in PCO2 at the very end of Phase 3, resulting from closure of lung units with lower PCO2 causing a little upstroke at the end of the ETCO2 waveform

Commonly seen in pregnant/obese patients-decreased FRC and LC
also denoted as Phase 4’

259
Q

Beta angle

A

separates Phase 3 and Phase 0
90 degreesish, can widen with **malfunctioning inspiratory uni valves, rebreathing, or guppy breathing(high RR, low TV)

260
Q

Normal Capnograph

A
261
Q

Inadequate ETT Cuff seal

A

Beta angle falls off as room air is being entrained around tube and Phase 3 is cut short

262
Q

Sample Line Leak

A

Note the read capping at 20mmHg
it’s half normal as the line is probably broken and room air is diluting the expired sample
the end jump is not phase 4 prime it’s not at 40mmHg nor an FRC/LC issue from being fat

263
Q

Hyperventilation wave form

A

Light anesthesia, Metabolic acidosis is leading to higher RR

264
Q

Hypoventilation capnography

A

ETCO2 is climbing
MH, Sepsis, fever, narcotics, hyperthyroidism, hypoventilation

265
Q

Airway obstruction capnograph

A

sharkfin, alpha angle is gone
phase 2 and 3 have merged

266
Q

Vent overbreathing

A

Patient is intiating breaths between mechanical breaths-if its a large wave they dont need support just dial in narcotics to 12-20 RR

with smaller patient breaths/wave theyre weak you could flip the vent off and close the APL valve a bit and depress the bag to support the tidal volume goal or reparalyze them/blast them fent

Clinical Reference Deck (4 decks)

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