Mod V: Anesthesia Machine Flashcards
Anesthesia Machine
T/F: Peds can be effectively anesthetized with a standard adult anesthesia machine and a standard ventilator
True
Anesthesia Machine
Which adjustments can/must be made to the standard anesthesia machine to compensate for smaller airway and smaller lung volumes?
Peds Breathing circuit
Pt’s Ventilation
Anesthesia Machine
Breathing circuit adjustment in peds:
Non-rebreathing circuit system
Mapleson and Bain
Circle breathing system
Semiclosed and closed
Change tubing and reservoir bag
Anesthesia Gas Machine- Breathing circuits
Anesthesia Machine
Ventilation adjustment in peds:
Spontaneous vs. controlled
Volume control vs. Pressure control ventilation
Anesthesia Machine
Must be able to deliver air to control FiO2, why
Retinopathy of prematurity
Anesthesia Machine
Abnormal proliferation of fibrous tissue immediately behind the lens of the eye, leading to blindness. It affected many premature babies in the 1950s, owing to the excessive administration of oxygen.
Retinopathy of prematurity (ROP)
Formaly knowns as retrolental fibroplasia
The risk of Retinopathy of prematurity (ROP) is inversely proportional to birth weight and is a/w neonate oxygen exposure, apnea, blood transfusion, sepsis and fluctuating levels of CO2
Anesthesia Machine
Why do you need to review your Air/O2 blending ratios
So you could dial in the amount of oxygen you want to deeiver and
Prevent complications such as Retinopathy of prematurity (ROP)
Anesthesia Machine
What’s the formula for calculating the ratio of Air/O2 flows when desired FiO2 to deliver is known?
Calculate Air flow = 100 - (desired % 02) = Air (L/min)
Calculate O2 flow = (Desired % 02) – 20 = O2 (L/min)
Ratio of Air/O2 flows = Air (L/min) ÷ 02 (L/min)
Anesthesia Machine
Calculate the flows of both O2 and air if you want to deliver an FiO2 of 28%, aka what’s the Air/O2 blending ratio to deliver 28% FiO2?
100-28 = 72 L/min of Air
28-20 = 8 L/min of O2
72:8 = 9
Air/O2 blending ratio to deliver 28% FiO2 is 9:1
Anesthesia Machine
The Air/O2 blending ratio to deliver 28% FiO2 is 9:1. How can you deliver this ration with less flow (you don’t really want o deliver 9L/min of Air)?
Maintain the same ratio at lower flow rates
Pediatric Breathing Circuits
What are the desired features of the ideal Pediatric Breathing Circuit?
Low dead space
Low resistance
Lightweight/compact
Low compression volume
Easily humidified
Easily scavenged
Economy of low FGF
Suitable for controlled or mechanical ventilation
Pediatric Breathing Circuits
Which Breathing Circuits are actually used in peds?
Standard adult breathing circuit
Pediatric circuit that are lighter and smaller in circumference in order to decrease deadspace
Anesthesia Ventilator
Any adult ventilator may be used in peds with appropriate adjustments made to which ventilation variables?
RR - FGF - VT
I:E ratio
Anesthesia Ventilator
Meticulous attention to settings PRIOR TO initiation of ventilation is essential in order to prevent:
Barotrauma
Anesthesia Ventilator - Pressure vs. Volume Control
What’s the major advantage of Pressure control ventilation?
Prevents overinflation/barotrauma
Pressure limited breath delivered at a set rate
VT determined by preset pressure limit
Pressure control is more forgiving!!!
Anesthesia Ventilator - Pressure vs. Volume Control
What is a potentially negative outcome of ↑ airway pressure with inspiration during Volume control ventilation?
LUNG BAROTRAUMA
Ventilation delivered with constant inspiratory flow to preset VT
VT delivered constant
Anesthesia Ventilator - Ventilator Settings
Which two variables are “limiting variables” during mechanical ventilation?
Pressure Limit vs. Volume Limit Setting
Anesthesia Ventilator - Ventilator Settings
What are adequate initial I:E settings for most children with normal lung compliance?
1:2
Anesthesia Ventilator - Ventilator Settings
What are adequate I:E settings for less compliant lungs?
1:1 or 2:1
Anesthesia Ventilator - Ventilator Settings
What’s the initial RR for newborns?
Rate for newborns
RR: 25 – 30
Anesthesia Ventilator - Ventilator Settings
What’s the initial RR for Children 1-8 years old?
Rate for Children 1-8 years old
RR: 12 – 15
Anesthesia Ventilator - Ventilator Settings
What’s the initial RR for Children older than 8?
Rate for Children older than 8
RR: 8 – 10
Anesthesia Ventilator - Ventilator Settings
What should your initial VT, to PIP be?
VT 10-15 ml/kg/breath, to PIP 20-25 cm H2O
IV Equipment/Set Up
It is safer to establish IV in all anesthetized pediatric pts. What are exceptions to this?
Very short, noninvasive procedures
(However, have set up & ready)
IV Equipment/Set Up
What the recommended IV catheter size for neonates?
24 ga
IV Equipment/Set Up
What the recommended IV catheter size for 1-5 y/o?
22 ga
IV Equipment/Set Up
What the recommended IV catheter size for >5 y/o?
20 ga
IV Equipment/Set Up
What’s a benefit of using Micro drip infusion set (60gtt/ml) with volume limiting device (burette)?
May be pre-filled with desired volume to be administered
This prevents accidental overhydration of pt, especially very small infants
IV Equipment/Set Up
What air safety devices would you use in those with known congenital heart defects?
All air bubbles purged Air filters
IV Equipment/Set Up
Why is important to terminate IV lines with T-connector especially in < 1y/o?
Allows direct injection of drug with minimal deadspace
Allows to give medication at the closet port possible that prevents unecessarily administration of additional IV fluid
This matters a lot in a neonate that could only tolerate a 25 mL infusion for the whole case for example
IV Equipment/Set Up
What’s a benefit of uing 3-way multiple-stopcock manifolds in procedures where blood or colloid may be necessary?
Allows mainline to continue infusing maintenance,
except during administration of blood or colloids
Warming Devices
Warming Devices are important because Hypothermia is common and could lead to:
Acidosis
Myocardial irritability
Bradycardia
Apnea
Prolonged Drug Effects (NMBD)
Warming Devices
What are the different mechanisms of heat loss?
Radiant
Conductive
Convective
Evaporative
Warming Devices
The type of heat loss whereby heat is transferred from one object to another that are not in contact with the body is also known as:
Radiant heat loss
Warming Devices
What’s the major determinant of the rate of radiant heat loss?
Temperature gradient btw child & near objects
Warming Devices
Heat loss through contact is also known as:
Conductive heat loss
Occurs through Bed, scales
Warming Devices
Heat loss from body to cooler air is also known as:
Convective heat loss
Warming Devices
Heat loss through vaporization of liquid from the body cavities & respiratory tract is also known as:
Evaporative heat loss
Could be Sensible(sweat) or Insensible (water thru skin)
Warming Devices
Which techniques or devices can be used in the OR to prevent hypothermia?
OR temp
Warm to 80-90˚ F before child arrives in OR
Radiant Warmers
During prep, induction, after drapes removed
Servomechanism temperature control (avoid skin burn)
Monitor skin (not core temp)
Max skin temp: 39˚ C
3 feet away
Warming Blankets (circulating water mattress)
Effective if < 10 kg
Fluid temp should not exceed 39˚
Avoid direct contact skin with mattress
Forced air warmers
Most effective
Combination of convection with warm air + plastic that reduces evaporative loss
Costly
Heat-moisture exchangers (HME)
Increase resistance to breathing
Clog with humidity over time
Heated humidifiers
May overheat
Wrapping
Reduces radiant and convective heat loss
“Space” blankets with reflective aluminized Mylar layers very effective
Covering head ↓ heat loss by 70%
Warming Devices
What should the OR temp be before the child arrives in OR?
Warmed to 80-90˚ F
Warming Devices
When and how should Radiant Warmers be used?
During prep, induction, after drapes removed
Servomechanism temperature control (avoid skin burn)
Monitor skin (not core temp)
Max skin temp: 39˚ C
Keep 3 feet away!!!
Warming Devices
Which temp should be monitored with radiant warmers use?
Skin temp (not core)
Warming Devices
What feature of Radiant warmers avoids skin burn?
Servomechanism temperature control
Warming Devices
What’s the maximun skin temp acceptable when using radiant warmers?
39˚ C
Warming Devices
At what distance should radiant warmers be placed away from the pt?
3 feet away
Warming Devices
Warming Blankets (circulating water mattress) are effective for pts weighing how much?
< 10 kg
Warming Devices
Warming Blankets (circulating water mattress), fluid temp should not exceed which temperature?
39˚ C
Warming Devices
T/F: When using warming Blankets (circulating water mattress), direct contact of skin with mattress must be avoided
True
Warming Devices
Which warming device utilizes a combination of convection with warm air + plastic that reduces evaporative loss, is considered the most effective warming device, and is however costly?
Forced air warmers
Warming Devices
Most effectie warming device:
Forced air warmers
Warming Devices
Disadvantages of Heat-moisture exchangers (HME)
Increase resistance to breathing
Clog with humidity over time
Warming Devices
Disadvantage of Heated humidifiers:
May overheat
Warming Devices
The warming technique that uses “Space” blankets with reflective aluminized Mylar layers an is very effective at reducing radiant and convective heat loss is also known as:
Wrapping
Warming Devices
Covering head with wrapping ↓ heat loss by what percentage?
70%
