Intravenous sedation I

Question 1

How to monitor pts under IV sedation?

Answer 1

Respiratory rate
10 – 18 per minute
Depth of breathing
Pattern of breathing
Cyanosis

Advanced - pulse oximetry (mandatory), carbon dioxide monitoring (optional)

Question 2

Pulse oximetry limitations?

Answer 2

Ambient light
Movement - poor attachment
Cold peripheries - vasoconstriction in fingers
Nail varnish - another layer for machine to go through
Measurement lag

Question 3

What is the average level of oxygen detected by pulse oximetry?

Answer 3

red 660nm and infrared 910nm

Gives the oxygen saturation of the blood

Question 4

What is Capnography?

Answer 4

Detects exhaled CO2 in breath 
Usually via nasal prongs
Wavelength displayed on monitor 
Allows confirmation of adequate ventilation and open airway 
Pt has to be breathing through nose

Question 5

Respiratory complications?

Answer 5

Upper airway obstruction

Hypoventilation

Question 6

How does upper airway obstruction occur? What can it lead to?

Answer 6

Sedation leads to a decrease in tone of the muscles of the pharynx
Leads to pharyngeal collapse, tongue falls against back wall of pharynx = blocked airway
Mild cases lead to partial airway obstruction
More severe leads to complete obstruction

Question 7

Signs of airway obstruction?

Answer 7

Snoring
Stridor
Drop in O2 saturations
Loss of CO2 trace
Seesaw respirator

Question 8

Management of airway obstruction?

Answer 8

Supplementary oxygen
Careful titration of sedation
Basic airway opening manoeuvres - jaw lift, chin lift and head lift = tongue moves with the jaw and obstruction is removed
Airway adjuncts

Question 9

How do sedative drugs cause hypoventilation? Effects of hypoventilation?

Answer 9

Sedative drugs sedate the respiratory centre in the brain
Also reduce receptor sensitivity to CO2
Leads to reduced respiratory rate or complete cessation of breathing
CO2 levels can build up = narcosis

Question 10

How to detect hypoventilation?

Answer 10

Monitor respiratory rate

Drop in oxygen saturation

Question 11

How to manage hypoventilation?

Answer 11

Reversal of sedation with flumazenil or naloxone

Assisted ventilation with self-inflating ambubag

Question 12

How to monitor the CV system?

Answer 12

HR from pulse oximeter
Heart rhythm
Conscious level 
Skin colour
Capillary refil - press on forehead for 5 secs and release it (about 2 secs is normal, more than 5 needs help)

Advanced - Non-invasive blood pressure (mandatory), ECG monitoring (optional)

Question 13

Non-invasive blood pressure monitoring?

Answer 13

Automated machines
Cuff around arm/calf
Automatic cycling - every 5 mins

Question 14

Non-invasive blood pressure is affected by?

Answer 14

Movement

Wrong size cuff (if too small will give higher blood pressure)

Question 15

When to do ECG monitoring? Why?

Answer 15

In pts with a history of significant CV disease
Can detect arrhythmias and also signs of cardiac ischaemia and infarction
Usually a 3 lead configuration

Question 16

CV complications?

Answer 16

Hypotension
Cardiac arrhythmias
Cardiac arrest

Question 17

Causes of hypotension?

Answer 17

Vasodilation caused by sedative drugs
Some drugs decrease strength of heart contraction

Dose related

Question 18

When is hypotension more likely to occur?

Answer 18

In the elderly and those with existing cardiovascular disease

Question 19

How to treat hypotension?

Answer 19

Prevention better than cure
Stop administering agent
Place pt head down and with feet elevated
IV fluids may be required

Question 20

Cardiac arrhythmias features?

Answer 20

Multi-factorial aetiology
May be precipitated by adrenaline in LA
More likely in elder and those with CVS disease
Raised blood CO2 levels also increase risk

Question 21

Tx for cardiac arrhythmias?

Answer 21

Call for expert help

ALS standard algorithms

Question 22

How to manage cardiac arrest?

Answer 22

CPR 30:2